Merge branch 'master' into libuv-0.10-headless-display

Conflicts:
	common/curl_request.cpp
	common/glfw_view.cpp
	common/glfw_view.hpp
	include/mbgl/platform/request.hpp
	ios/mapbox-gl-cocoa
	setup-libraries.sh
	src/map/map.cpp
	src/platform/request.cpp
	test/fixtures/fixture_request.cpp

42 files changed, 2518 insertions, 308 deletions

diff --git a/src/map/map.cpp b/src/map/map.cpp
index ad8749ff08..9034c6d5ac 100644
--- a/src/map/map.cpp
+++ b/src/map/map.cpp
@@ -19,11 +19,10 @@
 #include <mbgl/style/style_bucket.hpp>
 #include <mbgl/util/texturepool.hpp>
 #include <mbgl/geometry/sprite_atlas.hpp>
-#include <mbgl/util/filesource.hpp>
+#include <mbgl/storage/file_source.hpp>
 #include <mbgl/platform/log.hpp>
 
 #include <algorithm>
-#include <memory>
 #include <iostream>
 
 #define _USE_MATH_DEFINES
@@ -34,12 +33,15 @@ using namespace mbgl;
 Map::Map(View& view)
     : loop(std::make_shared<uv::loop>()),
       thread(std::make_unique<uv::thread>()),
+      async_terminate(new uv_async_t()),
+      async_render(new uv_async_t()),
+      async_cleanup(new uv_async_t()),
       view(view),
+#ifndef NDEBUG
+      main_thread(uv_thread_self()),
+#endif
       transform(view),
-      fileSource(std::make_shared<FileSource>()),
-      style(std::make_shared<Style>()),
       glyphAtlas(std::make_shared<GlyphAtlas>(1024, 1024)),
-      glyphStore(std::make_shared<GlyphStore>(fileSource)),
       spriteAtlas(std::make_shared<SpriteAtlas>(512, 512)),
       texturepool(std::make_shared<Texturepool>()),
       painter(*this) {
@@ -53,49 +55,93 @@ Map::Map(View& view)
 }
 
 Map::~Map() {
-    // Clear the style first before the rest of the constructor deletes members of this object.
-    // This is required because members of the style reference the Map object in their destructors.
-    style.reset();
-
     if (async) {
         stop();
     }
+
+    // Explicitly reset all pointers.
+    texturepool.reset();
+    sprite.reset();
+    spriteAtlas.reset();
+    glyphStore.reset();
+    glyphAtlas.reset();
+    style.reset();
+    fileSource.reset();
+    workers.reset();
+
+    uv_run(**loop, UV_RUN_DEFAULT);
+}
+
+uv::worker &Map::getWorker() {
+    if (!workers) {
+        workers = std::make_unique<uv::worker>(**loop, 4, "Tile Worker");
+    }
+    return *workers;
 }
 
 void Map::start() {
+    assert(uv_thread_self() == main_thread);
+    assert(!async);
+
     // When starting map rendering in another thread, we perform async/continuously
     // updated rendering. Only in these cases, we attach the async handlers.
     async = true;
 
+    // Reset the flag.
+    is_stopped = false;
+
     // Setup async notifications
-    async_terminate = new uv_async_t();
-    uv_async_init(**loop, async_terminate, terminate);
-    async_terminate->data = **loop;
+    uv_async_init(**loop, async_terminate.get(), terminate);
+    async_terminate->data = this;
 
-    async_render = new uv_async_t();
-    uv_async_init(**loop, async_render, render);
+    uv_async_init(**loop, async_render.get(), render);
     async_render->data = this;
 
-    async_cleanup = new uv_async_t();
-    uv_async_init(**loop, async_cleanup, cleanup);
+    uv_async_init(**loop, async_cleanup.get(), cleanup);
     async_cleanup->data = this;
 
     uv_thread_create(*thread, [](void *arg) {
         Map *map = static_cast<Map *>(arg);
+#ifndef NDEBUG
+        map->map_thread = uv_thread_self();
+#endif
+#ifdef __APPLE__
+        pthread_setname_np("Map");
+#endif
         map->run();
+#ifndef NDEBUG
+        map->map_thread = -1;
+#endif
+
+        // Make sure that the stop() function knows when to stop invoking the callback function.
+        map->is_stopped = true;
+        map->view.notify();
     }, this);
 }
 
-void Map::stop() {
-    if (async_terminate != nullptr) {
-        uv_async_send(async_terminate);
+void Map::stop(stop_callback cb, void *data) {
+    assert(uv_thread_self() == main_thread);
+    assert(main_thread != map_thread);
+    assert(async);
+
+    uv_async_send(async_terminate.get());
+
+    if (cb) {
+        // Wait until the render thread stopped. We are using this construct instead of plainly
+        // relying on the thread_join because the system might need to run things in the current
+        // thread that is required for the render thread to terminate correctly. This is for example
+        // the case with Cocoa's NSURLRequest. Otherwise, we will eventually deadlock because this
+        // thread (== main thread) is blocked. The callback function should use an efficient waiting
+        // function to avoid a busy waiting loop.
+        while (!is_stopped) {
+            cb(data);
+        }
     }
 
+    // If a callback function was provided, this should return immediately because the thread has
+    // already finished executing.
     uv_thread_join(*thread);
 
-    // Run the event loop once to make sure our async delete handlers are called.
-    uv_run(**loop, UV_RUN_ONCE);
-
     async = false;
 }
 
@@ -104,22 +150,35 @@ void Map::delete_async(uv_handle_t *handle, int status) {
 }
 
 void Map::run() {
+#ifndef NDEBUG
+    if (!async) {
+        map_thread = main_thread;
+    }
+#endif
+    assert(uv_thread_self() == map_thread);
+
     setup();
     prepare();
     uv_run(**loop, UV_RUN_DEFAULT);
 
+    // Run the event loop once more to make sure our async delete handlers are called.
+    uv_run(**loop, UV_RUN_ONCE);
+
     // If the map rendering wasn't started asynchronously, we perform one render
     // *after* all events have been processed.
     if (!async) {
         render();
+#ifndef NDEBUG
+        map_thread = -1;
+#endif
     }
 }
 
 void Map::rerender() {
     // We only send render events if we want to continuously update the map
     // (== async rendering).
-    if (async && async_render != nullptr) {
-        uv_async_send(async_render);
+    if (async) {
+        uv_async_send(async_render.get());
     }
 }
 
@@ -139,7 +198,7 @@ void Map::swapped() {
 
 void Map::cleanup() {
     if (async_cleanup != nullptr) {
-        uv_async_send(async_cleanup);
+        uv_async_send(async_cleanup.get());
     }
 }
 
@@ -153,9 +212,20 @@ void Map::terminate() {
     painter.terminate();
 }
 
+void Map::setReachability(bool reachable) {
+    // Note: This function may be called from *any* thread.
+    if (reachable) {
+        if (fileSource) {
+            fileSource->prepare([&]() {
+                fileSource->retryAllPending();
+            });
+        }
+    }
+}
+
 void Map::render(uv_async_t *async, int status) {
     Map *map = static_cast<Map *>(async->data);
-
+    assert(uv_thread_self() == map->map_thread);
 
     if (map->state.hasSize()) {
         if (map->is_rendered.test_and_set() == false) {
@@ -175,44 +245,48 @@ void Map::render(uv_async_t *async, int status) {
 
 void Map::terminate(uv_async_t *async, int status) {
     // Closes all open handles on the loop. This means that the loop will automatically terminate.
-    uv_loop_t *loop = static_cast<uv_loop_t *>(async->data);
-    uv_walk(loop, [](uv_handle_t *handle, void */*arg*/) {
-        if (!uv_is_closing(handle)) {
-            uv_close(handle, NULL);
-        }
-    }, NULL);
+    Map *map = static_cast<Map *>(async->data);
+    assert(uv_thread_self() == map->map_thread);
+
+    // Remove all of these to make sure they are destructed in the correct thread.
+    map->glyphStore.reset();
+    map->fileSource.reset();
+    map->style.reset();
+    map->workers.reset();
+    map->activeSources.clear();
+
+    uv_close((uv_handle_t *)map->async_cleanup.get(), nullptr);
+    uv_close((uv_handle_t *)map->async_render.get(), nullptr);
+    uv_close((uv_handle_t *)map->async_terminate.get(), nullptr);
 }
 
 #pragma mark - Setup
 
 void Map::setup() {
+    assert(uv_thread_self() == map_thread);
     view.make_active();
     painter.setup();
     view.make_inactive();
 }
 
 void Map::setStyleURL(const std::string &url) {
-    fileSource->load(ResourceType::JSON, url, [&](platform::Response *res) {
-        if (res->code == 200) {
-            // Calculate the base
-            const size_t pos = url.rfind('/');
-            std::string base = "";
-            if (pos != std::string::npos) {
-                base = url.substr(0, pos + 1);
-            }
-
-            this->setStyleJSON(res->body, base);
-        } else {
-            Log::Error(Event::Setup, "loading style failed: %d (%s)", res->code, res->error_message.c_str());
-        }
-    }, loop);
+    // TODO: Make threadsafe.
+    styleURL = url;
 }
 
 
 void Map::setStyleJSON(std::string newStyleJSON, const std::string &base) {
+    // TODO: Make threadsafe.
     styleJSON.swap(newStyleJSON);
     sprite.reset();
+    if (!style) {
+        style = std::make_shared<Style>();
+    }
     style->loadJSON((const uint8_t *)styleJSON.c_str());
+    if (!fileSource) {
+        fileSource = std::make_shared<FileSource>(**loop, platform::defaultCacheDatabase());
+        glyphStore = std::make_shared<GlyphStore>(fileSource);
+    }
     fileSource->setBase(base);
     glyphStore->setURL(util::mapbox::normalizeGlyphsURL(style->glyph_url, getAccessToken()));
     update();
@@ -223,6 +297,7 @@ std::string Map::getStyleJSON() const {
 }
 
 void Map::setAccessToken(std::string access_token) {
+    // TODO: Make threadsafe.
     accessToken.swap(access_token);
 }
 
@@ -230,7 +305,7 @@ std::string Map::getAccessToken() const {
     return accessToken;
 }
 
-std::shared_ptr<Sprite> Map::getSprite() {
+util::ptr<Sprite> Map::getSprite() {
     const float pixelRatio = state.getPixelRatio();
     const std::string &sprite_url = style->getSpriteURL();
     if (!sprite || sprite->pixelRatio != pixelRatio) {
@@ -460,8 +535,10 @@ void Map::setDefaultTransitionDuration(uint64_t duration_milliseconds) {
 }
 
 void Map::updateSources() {
+    assert(uv_thread_self() == map_thread);
+
     // First, disable all existing sources.
-    for (const std::shared_ptr<StyleSource> &source : activeSources) {
+    for (const util::ptr<StyleSource> &source : activeSources) {
         source->enabled = false;
     }
 
@@ -469,7 +546,7 @@ void Map::updateSources() {
     updateSources(style->layers);
 
     // Then, construct or destroy the actual source object, depending on enabled state.
-    for (const std::shared_ptr<StyleSource> &style_source : activeSources) {
+    for (const util::ptr<StyleSource> &style_source : activeSources) {
         if (style_source->enabled) {
             if (!style_source->source) {
                 style_source->source = std::make_shared<Source>(style_source->info);
@@ -481,20 +558,20 @@ void Map::updateSources() {
     }
 
     // Finally, remove all sources that are disabled.
-    util::erase_if(activeSources, [](std::shared_ptr<StyleSource> source){
+    util::erase_if(activeSources, [](util::ptr<StyleSource> source){
         return !source->enabled;
     });
 }
 
-const std::set<std::shared_ptr<StyleSource>> Map::getActiveSources() const {
+const std::set<util::ptr<StyleSource>> Map::getActiveSources() const {
     return activeSources;
 }
 
-void Map::updateSources(const std::shared_ptr<StyleLayerGroup> &group) {
+void Map::updateSources(const util::ptr<StyleLayerGroup> &group) {
     if (!group) {
         return;
     }
-    for (const std::shared_ptr<StyleLayer> &layer : group->layers) {
+    for (const util::ptr<StyleLayer> &layer : group->layers) {
         if (!layer) continue;
         if (layer->bucket) {
             if (layer->bucket->style_source) {
@@ -507,7 +584,7 @@ void Map::updateSources(const std::shared_ptr<StyleLayerGroup> &group) {
 }
 
 void Map::updateTiles() {
-    for (const std::shared_ptr<StyleSource> &source : getActiveSources()) {
+    for (const util::ptr<StyleSource> &source : getActiveSources()) {
         source->source->update(*this);
     }
 }
@@ -515,13 +592,37 @@ void Map::updateTiles() {
 void Map::updateRenderState() {
     // Update all clipping IDs.
     ClipIDGenerator generator;
-    for (const std::shared_ptr<StyleSource> &source : getActiveSources()) {
+    for (const util::ptr<StyleSource> &source : getActiveSources()) {
         generator.update(source->source->getLoadedTiles());
         source->source->updateMatrices(painter.projMatrix, state);
     }
 }
 
 void Map::prepare() {
+    if (!fileSource) {
+        fileSource = std::make_shared<FileSource>(**loop, platform::defaultCacheDatabase());
+        glyphStore = std::make_shared<GlyphStore>(fileSource);
+    }
+
+    if (!style) {
+        style = std::make_shared<Style>();
+
+        fileSource->request(ResourceType::JSON, styleURL)->onload([&](const Response &res) {
+            if (res.code == 200) {
+                // Calculate the base
+                const size_t pos = styleURL.rfind('/');
+                std::string base = "";
+                if (pos != std::string::npos) {
+                    base = styleURL.substr(0, pos + 1);
+                }
+
+                setStyleJSON(res.data, base);
+            } else {
+                Log::Error(Event::Setup, "loading style failed: %ld (%s)", res.code, res.message.c_str());
+            }
+        });
+    }
+
     // Update transform transitions.
     animationTime = util::now();
     if (transform.needsTransition()) {
@@ -568,7 +669,7 @@ void Map::render() {
     // This guarantees that we have at least one function per tile called.
     // When only rendering layers via the stylesheet, it's possible that we don't
     // ever visit a tile during rendering.
-    for (const std::shared_ptr<StyleSource> &source : getActiveSources()) {
+    for (const util::ptr<StyleSource> &source : getActiveSources()) {
         source->source->finishRender(painter);
     }
 
@@ -582,7 +683,7 @@ void Map::render() {
     view.make_inactive();
 }
 
-void Map::renderLayers(std::shared_ptr<StyleLayerGroup> group) {
+void Map::renderLayers(util::ptr<StyleLayerGroup> group) {
     if (!group) {
         // Make sure that we actually do have a layer group.
         return;
@@ -625,7 +726,7 @@ void Map::renderLayers(std::shared_ptr<StyleLayerGroup> group) {
     }
 }
 
-void Map::renderLayer(std::shared_ptr<StyleLayer> layer_desc, RenderPass pass, const Tile::ID* id, const mat4* matrix) {
+void Map::renderLayer(util::ptr<StyleLayer> layer_desc, RenderPass pass, const Tile::ID* id, const mat4* matrix) {
     if (layer_desc->type == StyleLayerType::Background) {
         // This layer defines a background color/image.
 
diff --git a/src/map/raster_tile_data.cpp b/src/map/raster_tile_data.cpp
index 182a614393..e7725b7abd 100644
--- a/src/map/raster_tile_data.cpp
+++ b/src/map/raster_tile_data.cpp
@@ -5,7 +5,7 @@
 using namespace mbgl;
 
 
-RasterTileData::RasterTileData(Tile::ID id, Map &map, const SourceInfo &source)
+RasterTileData::RasterTileData(Tile::ID id, Map &map, const util::ptr<SourceInfo> &source)
     : TileData(id, map, source),
     bucket(map.getTexturepool(), properties) {
 }
@@ -25,10 +25,10 @@ void RasterTileData::parse() {
     }
 }
 
-void RasterTileData::render(Painter &painter, std::shared_ptr<StyleLayer> layer_desc, const mat4 &matrix) {
+void RasterTileData::render(Painter &painter, util::ptr<StyleLayer> layer_desc, const mat4 &matrix) {
     bucket.render(painter, layer_desc, id, matrix);
 }
 
-bool RasterTileData::hasData(std::shared_ptr<StyleLayer> /*layer_desc*/) const {
+bool RasterTileData::hasData(util::ptr<StyleLayer> /*layer_desc*/) const {
     return bucket.hasData();
 }
diff --git a/src/map/source.cpp b/src/map/source.cpp
index 083e931b7a..36f1a71c84 100644
--- a/src/map/source.cpp
+++ b/src/map/source.cpp
@@ -6,7 +6,7 @@
 #include <mbgl/util/raster.hpp>
 #include <mbgl/util/string.hpp>
 #include <mbgl/util/texturepool.hpp>
-#include <mbgl/util/filesource.hpp>
+#include <mbgl/storage/file_source.hpp>
 #include <mbgl/util/vec.hpp>
 #include <mbgl/util/math.hpp>
 #include <mbgl/util/std.hpp>
@@ -20,7 +20,7 @@
 
 namespace mbgl {
 
-Source::Source(SourceInfo& info)
+Source::Source(const util::ptr<SourceInfo>& info)
     : info(info)
 {
 }
@@ -29,32 +29,33 @@ Source::Source(SourceInfo& info)
 // The reason this isn't part of the constructor is that calling shared_from_this() in
 // the constructor fails.
 void Source::load(Map& map) {
-    if (info.url.empty()) {
+    if (info->url.empty()) {
         loaded = true;
         return;
     }
 
-    std::string url = util::mapbox::normalizeSourceURL(info.url, map.getAccessToken());
-    std::shared_ptr<Source> source = shared_from_this();
+    std::string url = util::mapbox::normalizeSourceURL(info->url, map.getAccessToken());
+    util::ptr<Source> source = shared_from_this();
 
-    map.getFileSource()->load(ResourceType::JSON, url, [source, &map](platform::Response *res) {
-        if (res->code != 200) {
+    map.getFileSource()->request(ResourceType::JSON, url)->onload([source, &map](const Response &res) {
+        if (res.code != 200) {
             Log::Warning(Event::General, "failed to load source TileJSON");
             return;
         }
 
         rapidjson::Document d;
-        d.Parse<0>(res->body.c_str());
+        d.Parse<0>(res.data.c_str());
 
         if (d.HasParseError()) {
             Log::Warning(Event::General, "invalid source TileJSON");
             return;
         }
 
-        source->info.parseTileJSONProperties(d);
+        source->info->parseTileJSONProperties(d);
         source->loaded = true;
 
         map.update();
+
     });
 }
 
@@ -98,7 +99,7 @@ void Source::drawClippingMasks(Painter &painter) {
     }
 }
 
-void Source::render(Painter &painter, std::shared_ptr<StyleLayer> layer_desc) {
+void Source::render(Painter &painter, util::ptr<StyleLayer> layer_desc) {
     gl::group group(std::string("layer: ") + layer_desc->id);
     for (const std::pair<const Tile::ID, std::unique_ptr<Tile>> &pair : tiles) {
         Tile &tile = *pair.second;
@@ -108,7 +109,7 @@ void Source::render(Painter &painter, std::shared_ptr<StyleLayer> layer_desc) {
     }
 }
 
-void Source::render(Painter &painter, std::shared_ptr<StyleLayer> layer_desc, const Tile::ID &id, const mat4 &matrix) {
+void Source::render(Painter &painter, util::ptr<StyleLayer> layer_desc, const Tile::ID &id, const mat4 &matrix) {
     auto it = tiles.find(id);
     if (it != tiles.end() && it->second->data && it->second->data->state == TileData::State::parsed) {
         painter.renderTileLayer(*it->second, layer_desc, matrix);
@@ -183,9 +184,9 @@ TileData::State Source::addTile(Map &map, const Tile::ID& id) {
 
     if (!new_tile.data) {
         // If we don't find working tile data, we're just going to load it.
-        if (info.type == SourceType::Vector) {
+        if (info->type == SourceType::Vector) {
             new_tile.data = std::make_shared<VectorTileData>(normalized_id, map, info);
-        } else if (info.type == SourceType::Raster) {
+        } else if (info->type == SourceType::Raster) {
             new_tile.data = std::make_shared<RasterTileData>(normalized_id, map, info);
         } else {
             throw std::runtime_error("source type not implemented");
@@ -199,7 +200,7 @@ TileData::State Source::addTile(Map &map, const Tile::ID& id) {
 }
 
 double Source::getZoom(const TransformState& state) const {
-    double offset = std::log(util::tileSize / info.tile_size) / std::log(2);
+    double offset = std::log(util::tileSize / info->tile_size) / std::log(2);
     offset += (state.getPixelRatio() > 1.0 ? 1 :0);
     return state.getZoom() + offset;
 }
@@ -211,8 +212,8 @@ int32_t Source::coveringZoomLevel(const TransformState& state) const {
 std::forward_list<Tile::ID> Source::coveringTiles(const TransformState& state) const {
     int32_t z = coveringZoomLevel(state);
 
-    if (z < info.min_zoom) return {{}};
-    if (z > info.max_zoom) z = info.max_zoom;
+    if (z < info->min_zoom) return {{}};
+    if (z > info->max_zoom) z = info->max_zoom;
 
     // Map four viewport corners to pixel coordinates
     box points = state.cornersToBox(z);
@@ -285,8 +286,8 @@ bool Source::updateTiles(Map &map) {
     std::forward_list<Tile::ID> required = coveringTiles(map.getState());
 
     // Determine the overzooming/underzooming amounts.
-    int32_t minCoveringZoom = util::clamp<int32_t>(zoom - 10, info.min_zoom, info.max_zoom);
-    int32_t maxCoveringZoom = util::clamp<int32_t>(zoom + 1,  info.min_zoom, info.max_zoom);
+    int32_t minCoveringZoom = util::clamp<int32_t>(zoom - 10, info->min_zoom, info->max_zoom);
+    int32_t maxCoveringZoom = util::clamp<int32_t>(zoom + 1,  info->min_zoom, info->max_zoom);
 
     // Retain is a list of tiles that we shouldn't delete, even if they are not
     // the most ideal tile for the current viewport. This may include tiles like
@@ -333,7 +334,7 @@ bool Source::updateTiles(Map &map) {
 
     // Remove all the expired pointers from the set.
     util::erase_if(tile_data, [&retain_data](std::pair<const Tile::ID, std::weak_ptr<TileData>> &pair) {
-        const std::shared_ptr<TileData> tile = pair.second.lock();
+        const util::ptr<TileData> tile = pair.second.lock();
         if (!tile) {
             return true;
         }
diff --git a/src/map/sprite.cpp b/src/map/sprite.cpp
index af9413a0e3..c069ece45a 100644
--- a/src/map/sprite.cpp
+++ b/src/map/sprite.cpp
@@ -5,7 +5,7 @@
 
 #include <string>
 #include <mbgl/platform/platform.hpp>
-#include <mbgl/util/filesource.hpp>
+#include <mbgl/storage/file_source.hpp>
 #include <mbgl/util/uv_detail.hpp>
 #include <mbgl/util/std.hpp>
 
@@ -22,8 +22,8 @@ SpritePosition::SpritePosition(uint16_t x, uint16_t y, uint16_t width, uint16_t
       sdf(sdf) {
 }
 
-std::shared_ptr<Sprite> Sprite::Create(const std::string& base_url, float pixelRatio, const std::shared_ptr<FileSource> &fileSource) {
-    std::shared_ptr<Sprite> sprite(std::make_shared<Sprite>(Key(), base_url, pixelRatio));
+util::ptr<Sprite> Sprite::Create(const std::string& base_url, float pixelRatio, const util::ptr<FileSource> &fileSource) {
+    util::ptr<Sprite> sprite(std::make_shared<Sprite>(Key(), base_url, pixelRatio));
     sprite->load(fileSource);
     return sprite;
 }
@@ -51,7 +51,7 @@ Sprite::operator bool() const {
 // Note: This is a separate function that must be called exactly once after creation
 // The reason this isn't part of the constructor is that calling shared_from_this() in
 // the constructor fails.
-void Sprite::load(const std::shared_ptr<FileSource> &fileSource) {
+void Sprite::load(const util::ptr<FileSource> &fileSource) {
     if (!valid) {
         // Treat a non-existent sprite as a successfully loaded empty sprite.
         loadedImage = true;
@@ -60,30 +60,30 @@ void Sprite::load(const std::shared_ptr<FileSource> &fileSource) {
         return;
     }
 
-    std::shared_ptr<Sprite> sprite = shared_from_this();
+    util::ptr<Sprite> sprite = shared_from_this();
 
-    fileSource->load(ResourceType::JSON, jsonURL, [sprite](platform::Response *res) {
-        if (res->code == 200) {
-            sprite->body.swap(res->body);
+    fileSource->request(ResourceType::JSON, jsonURL)->onload([sprite](const Response &res) {
+        if (res.code == 200) {
+            sprite->body = res.data;
             sprite->parseJSON();
             sprite->complete();
         } else {
-            Log::Warning(Event::Sprite, "Failed to load sprite info: Error %d: %s", res->code, res->error_message.c_str());
+            Log::Warning(Event::Sprite, "Failed to load sprite info: Error %d: %s", res.code, res.message.c_str());
             if (!sprite->future.valid()) {
-                sprite->promise.set_exception(std::make_exception_ptr(std::runtime_error(res->error_message)));
+                sprite->promise.set_exception(std::make_exception_ptr(std::runtime_error(res.message)));
             }
         }
     });
 
-    fileSource->load(ResourceType::Image, spriteURL, [sprite](platform::Response *res) {
-        if (res->code == 200) {
-            sprite->image.swap(res->body);
+    fileSource->request(ResourceType::Image, spriteURL)->onload([sprite](const Response &res) {
+        if (res.code == 200) {
+            sprite->image = res.data;
             sprite->parseImage();
             sprite->complete();
         } else {
-            Log::Warning(Event::Sprite, "Failed to load sprite image: Error %d: %s", res->code, res->error_message.c_str());
+            Log::Warning(Event::Sprite, "Failed to load sprite image: Error %d: %s", res.code, res.message.c_str());
             if (!sprite->future.valid()) {
-                sprite->promise.set_exception(std::make_exception_ptr(std::runtime_error(res->error_message)));
+                sprite->promise.set_exception(std::make_exception_ptr(std::runtime_error(res.message)));
             }
         }
     });
diff --git a/src/map/tile_data.cpp b/src/map/tile_data.cpp
index 57afb8dadb..44e3826bf5 100644
--- a/src/map/tile_data.cpp
+++ b/src/map/tile_data.cpp
@@ -4,12 +4,12 @@
 
 #include <mbgl/util/token.hpp>
 #include <mbgl/util/string.hpp>
-#include <mbgl/util/filesource.hpp>
+#include <mbgl/storage/file_source.hpp>
 #include <mbgl/util/uv_detail.hpp>
 
 using namespace mbgl;
 
-TileData::TileData(Tile::ID id, Map &map, const SourceInfo &source)
+TileData::TileData(Tile::ID id, Map &map, const util::ptr<SourceInfo> &source)
     : id(id),
       state(State::initial),
       map(map),
@@ -29,10 +29,10 @@ const std::string TileData::toString() const {
 }
 
 void TileData::request() {
-    if (source.tiles.empty())
+    if (source->tiles.empty())
         return;
 
-    std::string url = source.tiles[(id.x + id.y) % source.tiles.size()];
+    std::string url = source->tiles[(id.x + id.y) % source->tiles.size()];
     url = util::replaceTokens(url, [&](const std::string &token) -> std::string {
         if (token == "z") return std::to_string(id.z);
         if (token == "x") return std::to_string(id.x);
@@ -45,21 +45,28 @@ void TileData::request() {
 
     // Note: Somehow this feels slower than the change to request_http()
     std::weak_ptr<TileData> weak_tile = shared_from_this();
-    map.getFileSource()->load(ResourceType::Tile, url, [weak_tile, url](platform::Response *res) {
-        std::shared_ptr<TileData> tile = weak_tile.lock();
+    req = map.getFileSource()->request(ResourceType::Tile, url);
+    req->onload([weak_tile, url](const Response &res) {
+        util::ptr<TileData> tile = weak_tile.lock();
         if (!tile || tile->state == State::obsolete) {
             // noop. Tile is obsolete and we're now just waiting for the refcount
             // to drop to zero for destruction.
-        } else if (res->code == 200) {
+            return;
+        }
+
+        // Clear the request object.
+        tile->req.reset();
+
+        if (res.code == 200) {
             tile->state = State::loaded;
 
-            tile->data.swap(res->body);
+            tile->data = res.data;
 
             // Schedule tile parsing in another thread
             tile->reparse();
         } else {
 #if defined(DEBUG)
-            fprintf(stderr, "[%s] tile loading failed: %d, %s\n", url.c_str(), res->code, res->error_message.c_str());
+            fprintf(stderr, "[%s] tile loading failed: %ld, %s\n", url.c_str(), res.code, res.message.c_str());
 #endif
         }
     });
@@ -68,7 +75,7 @@ void TileData::request() {
 void TileData::cancel() {
     if (state != State::obsolete) {
         state = State::obsolete;
-        platform::cancel_request_http(req.lock());
+        req.reset();
     }
 }
 
@@ -79,12 +86,12 @@ void TileData::reparse() {
 
     // We're creating a new work request. The work request deletes itself after it executed
     // the after work handler
-    new uv::work<std::shared_ptr<TileData>>(
-        map.getLoop(),
-        [](std::shared_ptr<TileData> &tile) {
+    new uv::work<util::ptr<TileData>>(
+        map.getWorker(),
+        [](util::ptr<TileData> &tile) {
             tile->parse();
         },
-        [](std::shared_ptr<TileData> &tile) {
+        [](util::ptr<TileData> &tile) {
             tile->afterParse();
             tile->map.update();
         },
diff --git a/src/map/tile_parser.cpp b/src/map/tile_parser.cpp
index 6923c1a422..3dc5cb9cef 100644
--- a/src/map/tile_parser.cpp
+++ b/src/map/tile_parser.cpp
@@ -38,19 +38,26 @@ namespace mbgl {
 TileParser::~TileParser() = default;
 
 TileParser::TileParser(const std::string &data, VectorTileData &tile,
-                       const std::shared_ptr<const Style> &style,
-                       const std::shared_ptr<GlyphAtlas> &glyphAtlas,
-                       const std::shared_ptr<GlyphStore> &glyphStore,
-                       const std::shared_ptr<SpriteAtlas> &spriteAtlas,
-                       const std::shared_ptr<Sprite> &sprite)
+                       const util::ptr<const Style> &style_,
+                       const util::ptr<GlyphAtlas> &glyphAtlas_,
+                       const util::ptr<GlyphStore> &glyphStore_,
+                       const util::ptr<SpriteAtlas> &spriteAtlas_,
+                       const util::ptr<Sprite> &sprite_)
     : vector_data(pbf((const uint8_t *)data.data(), data.size())),
       tile(tile),
-      style(style),
-      glyphAtlas(glyphAtlas),
-      glyphStore(glyphStore),
-      spriteAtlas(spriteAtlas),
-      sprite(sprite),
-      collision(std::make_unique<Collision>(tile.id.z, 4096, tile.source.tile_size, tile.depth)) {
+      style(style_),
+      glyphAtlas(glyphAtlas_),
+      glyphStore(glyphStore_),
+      spriteAtlas(spriteAtlas_),
+      sprite(sprite_),
+      collision(std::make_unique<Collision>(tile.id.z, 4096, tile.source->tile_size, tile.depth)) {
+    assert(&tile != nullptr);
+    assert(style);
+    assert(glyphAtlas);
+    assert(glyphStore);
+    assert(spriteAtlas);
+    assert(sprite);
+    assert(collision);
 }
 
 void TileParser::parse() {
@@ -59,12 +66,12 @@ void TileParser::parse() {
 
 bool TileParser::obsolete() const { return tile.state == TileData::State::obsolete; }
 
-void TileParser::parseStyleLayers(std::shared_ptr<StyleLayerGroup> group) {
+void TileParser::parseStyleLayers(util::ptr<StyleLayerGroup> group) {
     if (!group) {
         return;
     }
 
-    for (const std::shared_ptr<StyleLayer> &layer_desc : group->layers) {
+    for (const util::ptr<StyleLayer> &layer_desc : group->layers) {
         // Cancel early when parsing.
         if (obsolete()) {
             return;
@@ -96,14 +103,14 @@ void TileParser::parseStyleLayers(std::shared_ptr<StyleLayerGroup> group) {
     }
 }
 
-std::unique_ptr<Bucket> TileParser::createBucket(std::shared_ptr<StyleBucket> bucket_desc) {
+std::unique_ptr<Bucket> TileParser::createBucket(util::ptr<StyleBucket> bucket_desc) {
     if (!bucket_desc) {
         fprintf(stderr, "missing bucket desc\n");
         return nullptr;
     }
 
     // Skip this bucket if we are to not render this
-    if (tile.id.z < std::floor(bucket_desc->min_zoom) && std::floor(bucket_desc->min_zoom) < tile.source.max_zoom) return nullptr;
+    if (tile.id.z < std::floor(bucket_desc->min_zoom) && std::floor(bucket_desc->min_zoom) < tile.source->max_zoom) return nullptr;
     if (tile.id.z >= std::ceil(bucket_desc->max_zoom)) return nullptr;
 
     auto layer_it = vector_data.layers.find(bucket_desc->source_layer);
@@ -157,7 +164,7 @@ std::unique_ptr<Bucket> TileParser::createFillBucket(const VectorTileLayer& laye
     return obsolete() ? nullptr : std::move(bucket);
 }
 
-std::unique_ptr<Bucket> TileParser::createRasterBucket(const std::shared_ptr<Texturepool> &texturepool, const StyleBucketRaster &raster) {
+std::unique_ptr<Bucket> TileParser::createRasterBucket(const util::ptr<Texturepool> &texturepool, const StyleBucketRaster &raster) {
     std::unique_ptr<RasterBucket> bucket = std::make_unique<RasterBucket>(texturepool, raster);
     return obsolete() ? nullptr : std::move(bucket);
 }
diff --git a/src/map/transform.cpp b/src/map/transform.cpp
index 6c5e70cc2f..baa615b94a 100644
--- a/src/map/transform.cpp
+++ b/src/map/transform.cpp
@@ -466,7 +466,7 @@ bool Transform::needsTransition() const {
 void Transform::updateTransitions(const timestamp now) {
     uv::writelock lock(mtx);
 
-    transitions.remove_if([now](const std::shared_ptr<util::transition> &transition) {
+    transitions.remove_if([now](const util::ptr<util::transition> &transition) {
         return transition->update(now) == util::transition::complete;
     });
 }
diff --git a/src/map/vector_tile_data.cpp b/src/map/vector_tile_data.cpp
index 1f74cab1d7..48b46059a5 100644
--- a/src/map/vector_tile_data.cpp
+++ b/src/map/vector_tile_data.cpp
@@ -8,13 +8,13 @@
 
 using namespace mbgl;
 
-VectorTileData::VectorTileData(Tile::ID id, Map &map, const SourceInfo &source)
+VectorTileData::VectorTileData(Tile::ID id, Map &map, const util::ptr<SourceInfo> &source)
     : TileData(id, map, source),
-      depth(id.z >= source.max_zoom ? map.getMaxZoom() - id.z : 1) {
+      depth(id.z >= source->max_zoom ? map.getMaxZoom() - id.z : 1) {
 }
 
 VectorTileData::~VectorTileData() {
-    std::shared_ptr<GlyphAtlas> glyphAtlas = map.getGlyphAtlas();
+    util::ptr<GlyphAtlas> glyphAtlas = map.getGlyphAtlas();
     if (glyphAtlas) {
         glyphAtlas->removeGlyphs(id.to_uint64());
     }
@@ -52,7 +52,7 @@ void VectorTileData::afterParse() {
     parser.reset();
 }
 
-void VectorTileData::render(Painter &painter, std::shared_ptr<StyleLayer> layer_desc, const mat4 &matrix) {
+void VectorTileData::render(Painter &painter, util::ptr<StyleLayer> layer_desc, const mat4 &matrix) {
     if (state == State::parsed && layer_desc->bucket) {
         auto databucket_it = buckets.find(layer_desc->bucket->name);
         if (databucket_it != buckets.end()) {
@@ -62,7 +62,7 @@ void VectorTileData::render(Painter &painter, std::shared_ptr<StyleLayer> layer_
     }
 }
 
-bool VectorTileData::hasData(std::shared_ptr<StyleLayer> layer_desc) const {
+bool VectorTileData::hasData(util::ptr<StyleLayer> layer_desc) const {
     if (state == State::parsed && layer_desc->bucket) {
         auto databucket_it = buckets.find(layer_desc->bucket->name);
         if (databucket_it != buckets.end()) {
diff --git a/src/platform/request.cpp b/src/platform/request.cpp
deleted file mode 100644
index 82e80b9a7c..0000000000
--- a/src/platform/request.cpp
+++ /dev/null
@@ -1,54 +0,0 @@
-#include <mbgl/platform/request.hpp>
-#include <mbgl/platform/platform.hpp>
-#include <mbgl/util/std.hpp>
-#include <mbgl/util/uv_detail.hpp>
-
-using namespace mbgl::platform;
-
-Request::Request(const std::string &url,
-                 std::function<void(Response *)> callback,
-                 std::shared_ptr<uv::loop> loop)
-    : url(url),
-      res(std::make_unique<Response>(callback)),
-      cancelled(false),
-      loop(loop) {
-    if (loop) {
-        // Add a check handle without a callback to keep the default loop running.
-        // We don't have a real handler attached to the default loop right from the
-        // beginning, because we're using asynchronous messaging to perform the actual
-        // request in the request thread. Only after the request is complete, we
-        // create an actual work request that is attached to the default loop.
-        async = new uv_async_t();
-        async->data = new std::unique_ptr<Response>();
-        uv_async_init(**loop, async, &complete);
-    }
-}
-
-Request::~Request() {
-}
-
-void Request::complete() {
-    if (loop) {
-        // We're scheduling the response callback to be invoked in the event loop.
-        // Since the Request object will be deleted before the callback is invoked,
-        // we move over the Response object to be owned by the async handle.
-        ((std::unique_ptr<Response> *)async->data)->swap(res);
-        uv_async_send(async);
-    } else {
-        // We're calling the response callback immediately. We're currently on an
-        // arbitrary thread, but that's okay.
-        res->callback(res.get());
-    }
-}
-
-void Request::complete(uv_async_t *async, int status) {
-    Response *res = static_cast<std::unique_ptr<Response> *>(async->data)->get();
-
-    res->callback(res);
-
-    // We need to remove our async handle again to allow the main event loop to exit.
-    uv_close((uv_handle_t *)async, [](uv_handle_t *handle) {
-        delete static_cast<std::unique_ptr<Response> *>(handle->data);
-        delete (uv_async_t *)handle;
-    });
-}
diff --git a/src/renderer/debug_bucket.cpp b/src/renderer/debug_bucket.cpp
index a3ac329f49..699c1c1db9 100644
--- a/src/renderer/debug_bucket.cpp
+++ b/src/renderer/debug_bucket.cpp
@@ -14,7 +14,7 @@ DebugBucket::DebugBucket(DebugFontBuffer& fontBuffer)
     : fontBuffer(fontBuffer) {
 }
 
-void DebugBucket::render(Painter& painter, std::shared_ptr<StyleLayer> /*layer_desc*/, const Tile::ID& /*id*/, const mat4 &matrix) {
+void DebugBucket::render(Painter& painter, util::ptr<StyleLayer> /*layer_desc*/, const Tile::ID& /*id*/, const mat4 &matrix) {
     painter.renderDebugText(*this, matrix);
 }
 
diff --git a/src/renderer/fill_bucket.cpp b/src/renderer/fill_bucket.cpp
index 875cc279b9..5358cae0b2 100644
--- a/src/renderer/fill_bucket.cpp
+++ b/src/renderer/fill_bucket.cpp
@@ -204,7 +204,7 @@ void FillBucket::tessellate() {
     lineGroup.vertex_length += total_vertex_count;
 }
 
-void FillBucket::render(Painter& painter, std::shared_ptr<StyleLayer> layer_desc, const Tile::ID& id, const mat4 &matrix) {
+void FillBucket::render(Painter& painter, util::ptr<StyleLayer> layer_desc, const Tile::ID& id, const mat4 &matrix) {
     painter.renderFill(*this, layer_desc, id, matrix);
 }
 
diff --git a/src/renderer/line_bucket.cpp b/src/renderer/line_bucket.cpp
index 2e89a7c35d..3ef7411be6 100644
--- a/src/renderer/line_bucket.cpp
+++ b/src/renderer/line_bucket.cpp
@@ -341,7 +341,7 @@ void LineBucket::addGeometry(const std::vector<Coordinate>& vertices) {
     }
 }
 
-void LineBucket::render(Painter& painter, std::shared_ptr<StyleLayer> layer_desc, const Tile::ID& id, const mat4 &matrix) {
+void LineBucket::render(Painter& painter, util::ptr<StyleLayer> layer_desc, const Tile::ID& id, const mat4 &matrix) {
     painter.renderLine(*this, layer_desc, id, matrix);
 }
 
diff --git a/src/renderer/painter.cpp b/src/renderer/painter.cpp
index 0d01fd1662..8988112585 100644
--- a/src/renderer/painter.cpp
+++ b/src/renderer/painter.cpp
@@ -197,7 +197,7 @@ void Painter::prepareTile(const Tile& tile) {
     glStencilFunc(GL_EQUAL, ref, mask);
 }
 
-void Painter::renderTileLayer(const Tile& tile, std::shared_ptr<StyleLayer> layer_desc, const mat4 &matrix) {
+void Painter::renderTileLayer(const Tile& tile, util::ptr<StyleLayer> layer_desc, const mat4 &matrix) {
     assert(tile.data);
     if (tile.data->hasData(layer_desc) || layer_desc->type == StyleLayerType::Raster) {
         gl::group group(util::sprintf<32>("render %d/%d/%d\n", tile.id.z, tile.id.y, tile.id.z));
@@ -206,7 +206,7 @@ void Painter::renderTileLayer(const Tile& tile, std::shared_ptr<StyleLayer> laye
     }
 }
 
-void Painter::renderBackground(std::shared_ptr<StyleLayer> layer_desc) {
+void Painter::renderBackground(util::ptr<StyleLayer> layer_desc) {
     const BackgroundProperties& properties = layer_desc->getProperties<BackgroundProperties>();
 
     Color color = properties.color;
diff --git a/src/renderer/painter_clipping.cpp b/src/renderer/painter_clipping.cpp
index 45b14a2f78..dc625ded4e 100644
--- a/src/renderer/painter_clipping.cpp
+++ b/src/renderer/painter_clipping.cpp
@@ -6,7 +6,7 @@
 
 using namespace mbgl;
 
-void Painter::drawClippingMasks(const std::set<std::shared_ptr<StyleSource>> &sources) {
+void Painter::drawClippingMasks(const std::set<util::ptr<StyleSource>> &sources) {
     gl::group group("clipping masks");
 
     useProgram(plainShader->program);
@@ -17,7 +17,7 @@ void Painter::drawClippingMasks(const std::set<std::shared_ptr<StyleSource>> &so
 
     coveringPlainArray.bind(*plainShader, tileStencilBuffer, BUFFER_OFFSET(0));
 
-    for (const std::shared_ptr<StyleSource> &source : sources) {
+    for (const util::ptr<StyleSource> &source : sources) {
         source->source->drawClippingMasks(*this);
     }
 
diff --git a/src/renderer/painter_fill.cpp b/src/renderer/painter_fill.cpp
index 6d56b9077e..6c17ab037a 100644
--- a/src/renderer/painter_fill.cpp
+++ b/src/renderer/painter_fill.cpp
@@ -10,7 +10,7 @@
 
 using namespace mbgl;
 
-void Painter::renderFill(FillBucket& bucket, std::shared_ptr<StyleLayer> layer_desc, const Tile::ID& id, const mat4 &matrix) {
+void Painter::renderFill(FillBucket& bucket, util::ptr<StyleLayer> layer_desc, const Tile::ID& id, const mat4 &matrix) {
     // Abort early.
     if (!bucket.hasData()) return;
 
diff --git a/src/renderer/painter_line.cpp b/src/renderer/painter_line.cpp
index 161abcd6ff..cd973b46d6 100644
--- a/src/renderer/painter_line.cpp
+++ b/src/renderer/painter_line.cpp
@@ -8,7 +8,7 @@
 
 using namespace mbgl;
 
-void Painter::renderLine(LineBucket& bucket, std::shared_ptr<StyleLayer> layer_desc, const Tile::ID& id, const mat4 &matrix) {
+void Painter::renderLine(LineBucket& bucket, util::ptr<StyleLayer> layer_desc, const Tile::ID& id, const mat4 &matrix) {
     // Abort early.
     if (pass == RenderPass::Opaque) return;
     if (!bucket.hasData()) return;
@@ -62,7 +62,7 @@ void Painter::renderLine(LineBucket& bucket, std::shared_ptr<StyleLayer> layer_d
         bucket.drawPoints(*linejoinShader);
     }
 
-    const std::shared_ptr<Sprite> &sprite = map.getSprite();
+    const util::ptr<Sprite> &sprite = map.getSprite();
     if (properties.image.size() && sprite) {
         SpriteAtlasPosition imagePos = map.getSpriteAtlas()->getPosition(properties.image, *sprite);
 
diff --git a/src/renderer/painter_raster.cpp b/src/renderer/painter_raster.cpp
index 7f7afc3e84..c362042e55 100644
--- a/src/renderer/painter_raster.cpp
+++ b/src/renderer/painter_raster.cpp
@@ -9,7 +9,7 @@
 
 using namespace mbgl;
 
-void Painter::renderRaster(RasterBucket& bucket, std::shared_ptr<StyleLayer> layer_desc, const Tile::ID& id, const mat4 &matrix) {
+void Painter::renderRaster(RasterBucket& bucket, util::ptr<StyleLayer> layer_desc, const Tile::ID& id, const mat4 &matrix) {
     if (pass != RenderPass::Translucent) return;
 
     const RasterProperties &properties = layer_desc->getProperties<RasterProperties>();
@@ -34,7 +34,7 @@ void Painter::renderRaster(RasterBucket& bucket, std::shared_ptr<StyleLayer> lay
             // call updateTiles to get parsed data for sublayers
             map.updateTiles();
 
-            for (const std::shared_ptr<StyleLayer> &layer : layer_desc->layers->layers) {
+            for (const util::ptr<StyleLayer> &layer : layer_desc->layers->layers) {
                 setOpaque();
                 map.renderLayer(layer, RenderPass::Opaque, &id, &preMatrix);
                 setTranslucent();
diff --git a/src/renderer/painter_symbol.cpp b/src/renderer/painter_symbol.cpp
index 4fce66217f..415dead70e 100644
--- a/src/renderer/painter_symbol.cpp
+++ b/src/renderer/painter_symbol.cpp
@@ -112,7 +112,7 @@ void Painter::renderSDF(SymbolBucket &bucket,
     }
 }
 
-void Painter::renderSymbol(SymbolBucket &bucket, std::shared_ptr<StyleLayer> layer_desc, const Tile::ID &id, const mat4 &matrix) {
+void Painter::renderSymbol(SymbolBucket &bucket, util::ptr<StyleLayer> layer_desc, const Tile::ID &id, const mat4 &matrix) {
     // Abort early.
     if (pass == RenderPass::Opaque) {
         return;
diff --git a/src/renderer/raster_bucket.cpp b/src/renderer/raster_bucket.cpp
index 492eea980d..fc5e3dd3c8 100644
--- a/src/renderer/raster_bucket.cpp
+++ b/src/renderer/raster_bucket.cpp
@@ -3,13 +3,13 @@
 
 using namespace mbgl;
 
-RasterBucket::RasterBucket(const std::shared_ptr<Texturepool> &texturepool, const StyleBucketRaster& properties)
+RasterBucket::RasterBucket(const util::ptr<Texturepool> &texturepool, const StyleBucketRaster& properties)
 : properties(properties),
   texture(properties),
   raster(texturepool) {
 }
 
-void RasterBucket::render(Painter &painter, std::shared_ptr<StyleLayer> layer_desc, const Tile::ID &id, const mat4 &matrix) {
+void RasterBucket::render(Painter &painter, util::ptr<StyleLayer> layer_desc, const Tile::ID &id, const mat4 &matrix) {
     painter.renderRaster(*this, layer_desc, id, matrix);
 }
 
diff --git a/src/renderer/symbol_bucket.cpp b/src/renderer/symbol_bucket.cpp
index 374ea2dc26..3a4b017ef3 100644
--- a/src/renderer/symbol_bucket.cpp
+++ b/src/renderer/symbol_bucket.cpp
@@ -22,7 +22,7 @@ namespace mbgl {
 SymbolBucket::SymbolBucket(const StyleBucketSymbol &properties, Collision &collision)
     : properties(properties), collision(collision) {}
 
-void SymbolBucket::render(Painter &painter, std::shared_ptr<StyleLayer> layer_desc,
+void SymbolBucket::render(Painter &painter, util::ptr<StyleLayer> layer_desc,
                           const Tile::ID &id, const mat4 &matrix) {
     painter.renderSymbol(*this, layer_desc, id, matrix);
 }
diff --git a/src/storage/base_request.cpp b/src/storage/base_request.cpp
new file mode 100644
index 0000000000..e87679ae1b
--- /dev/null
+++ b/src/storage/base_request.cpp
@@ -0,0 +1,86 @@
+#include <mbgl/storage/base_request.hpp>
+#include <mbgl/storage/response.hpp>
+#include <mbgl/storage/request.hpp>
+
+#include <uv.h>
+
+#include <cassert>
+
+namespace mbgl {
+
+template <typename T, typename ...Args>
+void invoke(const std::forward_list<std::unique_ptr<Callback>> &list, Args&& ...args) {
+    for (const std::unique_ptr<Callback> &callback : list) {
+        assert(callback);
+        if (callback->is<T>()) {
+            callback->get<T>()(::std::forward<Args>(args)...);
+        }
+    }
+}
+
+BaseRequest::BaseRequest(const std::string &path_) : thread_id(uv_thread_self()), path(path_) {
+}
+
+// A base request can only be "canceled" by destroying the object. In that case, we'll have to
+// notify all cancel callbacks.
+BaseRequest::~BaseRequest() {
+    assert(thread_id == uv_thread_self());
+    notify();
+}
+
+void BaseRequest::retryImmediately() {
+    // no-op. override in child class.
+}
+
+void BaseRequest::notify() {
+    assert(thread_id == uv_thread_self());
+
+    // The parameter exists solely so that any calls to ->remove()
+    // are not going to cause deallocation of this object while this call is in progress.
+    util::ptr<BaseRequest> retain = self;
+
+    // Swap the lists so that it's safe for callbacks to call ->cancel()
+    // on the request object, which would modify the list.
+    const std::forward_list<std::unique_ptr<Callback>> list = std::move(callbacks);
+    callbacks.clear();
+
+    if (response) {
+        invoke<CompletedCallback>(list, *response);
+    } else {
+        invoke<AbortedCallback>(list);
+    }
+
+    self.reset();
+}
+
+Callback *BaseRequest::add(Callback &&callback, const util::ptr<BaseRequest> &request) {
+    assert(thread_id == uv_thread_self());
+    assert(this == request.get());
+
+    if (response) {
+        // We already have a response. Notify right away.
+        if (callback.is<CompletedCallback>()) {
+            callback.get<CompletedCallback>()(*response);
+        } else {
+            // We already know that this request was successful. The AbortedCallback will be discarded
+            // here since it would never be called.
+        }
+        return nullptr;
+    } else {
+        self = request;
+        callbacks.push_front(std::unique_ptr<Callback>(new Callback(std::move(callback))));
+        return callbacks.front().get();
+    }
+}
+
+void BaseRequest::remove(Callback *callback) {
+    assert(thread_id == uv_thread_self());
+    callbacks.remove_if([=](const std::unique_ptr<Callback> &cb) {
+        return cb.get() == callback;
+    });
+    if (callbacks.empty()) {
+        self.reset();
+    }
+}
+
+}
diff --git a/src/storage/file_request.cpp b/src/storage/file_request.cpp
new file mode 100644
index 0000000000..33398d5ef1
--- /dev/null
+++ b/src/storage/file_request.cpp
@@ -0,0 +1,37 @@
+#include <mbgl/storage/file_request.hpp>
+#include <mbgl/storage/file_request_baton.hpp>
+#include <mbgl/storage/response.hpp>
+
+#include <uv.h>
+
+#include <cassert>
+
+#include <unistd.h>
+
+namespace mbgl {
+
+FileRequest::FileRequest(const std::string &path_, uv_loop_t *loop)
+    : BaseRequest(path_), ptr(new FileRequestBaton(this, path, loop)) {
+}
+
+void FileRequest::cancel() {
+    assert(thread_id == uv_thread_self());
+
+    if (ptr) {
+        ptr->cancel();
+
+        // When deleting a FileRequest object with a uv_fs_* call is in progress, we are making sure
+        // that the callback doesn't accidentally reference this object again.
+        ptr->request = nullptr;
+        ptr = nullptr;
+    }
+
+    notify();
+}
+
+FileRequest::~FileRequest() {
+    assert(thread_id == uv_thread_self());
+    cancel();
+}
+
+}
diff --git a/src/storage/file_request_baton.cpp b/src/storage/file_request_baton.cpp
new file mode 100644
index 0000000000..127c78f3e5
--- /dev/null
+++ b/src/storage/file_request_baton.cpp
@@ -0,0 +1,142 @@
+#include <mbgl/storage/file_request_baton.hpp>
+#include <mbgl/storage/file_request.hpp>
+#include <mbgl/storage/response.hpp>
+
+namespace mbgl {
+
+FileRequestBaton::FileRequestBaton(FileRequest *request_, const std::string &path, uv_loop_t *loop)
+    : thread_id(uv_thread_self()), request(request_) {
+    req.data = this;
+    uv_fs_open(loop, &req, path.c_str(), O_RDONLY, S_IRUSR, file_opened);
+}
+
+FileRequestBaton::~FileRequestBaton() {
+}
+
+void FileRequestBaton::cancel() {
+    canceled = true;
+
+    // uv_cancel fails frequently when the request has already been started.
+    // In that case, we have to let it complete and check the canceled bool
+    // instead.
+    uv_cancel((uv_req_t *)&req);
+}
+
+void FileRequestBaton::notify_error(uv_fs_t *req) {
+    FileRequestBaton *ptr = (FileRequestBaton *)req->data;
+    assert(ptr->thread_id == uv_thread_self());
+
+    if (ptr->request && req->result < 0 && !ptr->canceled && req->result != UV_ECANCELED) {
+        ptr->request->response = std::unique_ptr<Response>(new Response);
+        ptr->request->response->code = req->result == UV_ENOENT ? 404 : 500;
+        ptr->request->response->message = uv_strerror(int(req->result));
+        ptr->request->notify();
+    }
+}
+
+void FileRequestBaton::file_opened(uv_fs_t *req) {
+    FileRequestBaton *ptr = (FileRequestBaton *)req->data;
+    assert(ptr->thread_id == uv_thread_self());
+
+    if (req->result < 0) {
+        // Opening failed or was canceled. There isn't much left we can do.
+        notify_error(req);
+        cleanup(req);
+    } else {
+        const uv_file fd = uv_file(req->result);
+
+        // We're going to reuse this handle, so we need to cleanup first.
+        uv_fs_req_cleanup(req);
+
+        if (ptr->canceled || !ptr->request) {
+            // Either the FileRequest object has been destructed, or the
+            // request was canceled.
+            uv_fs_close(req->loop, req, fd, file_closed);
+        } else {
+            ptr->fd = fd;
+            uv_fs_fstat(req->loop, req, fd, file_stated);
+        }
+    }
+}
+
+void FileRequestBaton::file_stated(uv_fs_t *req) {
+    FileRequestBaton *ptr = (FileRequestBaton *)req->data;
+    assert(ptr->thread_id == uv_thread_self());
+
+    if (req->result < 0 || ptr->canceled || !ptr->request) {
+        // Stating failed or was canceled. We already have an open file handle
+        // though, which we'll have to close.
+        notify_error(req);
+
+        uv_fs_req_cleanup(req);
+        uv_fs_close(req->loop, req, ptr->fd, file_closed);
+    } else {
+        if (static_cast<const uv_stat_t *>(req->ptr)->st_size > std::numeric_limits<int>::max()) {
+            // File is too large for us to open this way because uv_buf's only support unsigned
+            // ints as maximum size.
+            if (ptr->request) {
+                ptr->request->response = std::unique_ptr<Response>(new Response);
+                ptr->request->response->code = UV_EFBIG;
+                ptr->request->response->message = uv_strerror(UV_EFBIG);
+                ptr->request->notify();
+            }
+
+            uv_fs_req_cleanup(req);
+            uv_fs_close(req->loop, req, ptr->fd, file_closed);
+        } else {
+            const unsigned int size =
+                (unsigned int)(static_cast<const uv_stat_t *>(req->ptr)->st_size);
+            ptr->body.resize(size);
+            ptr->buffer = uv_buf_init(const_cast<char *>(ptr->body.data()), size);
+            uv_fs_req_cleanup(req);
+            uv_fs_read(req->loop, req, ptr->fd, &ptr->buffer, 1, 0, file_read);
+        }
+    }
+}
+
+void FileRequestBaton::file_read(uv_fs_t *req) {
+    FileRequestBaton *ptr = (FileRequestBaton *)req->data;
+    assert(ptr->thread_id == uv_thread_self());
+
+    if (req->result < 0 || ptr->canceled || !ptr->request) {
+        // Stating failed or was canceled. We already have an open file handle
+        // though, which we'll have to close.
+        notify_error(req);
+    } else {
+        // File was successfully read.
+        if (ptr->request) {
+            ptr->request->response = std::unique_ptr<Response>(new Response);
+            ptr->request->response->code = 200;
+            ptr->request->response->data = std::move(ptr->body);
+            ptr->request->notify();
+        }
+    }
+
+    uv_fs_req_cleanup(req);
+    uv_fs_close(req->loop, req, ptr->fd, file_closed);
+}
+
+void FileRequestBaton::file_closed(uv_fs_t *req) {
+    FileRequestBaton *ptr = (FileRequestBaton *)req->data;
+    assert(ptr->thread_id == uv_thread_self());
+
+    if (req->result < 0) {
+        // Closing the file failed. But there isn't anything we can do.
+    }
+
+    cleanup(req);
+}
+
+void FileRequestBaton::cleanup(uv_fs_t *req) {
+    FileRequestBaton *ptr = (FileRequestBaton *)req->data;
+    assert(ptr->thread_id == uv_thread_self());
+
+    if (ptr->request) {
+        ptr->request->ptr = nullptr;
+    }
+
+    uv_fs_req_cleanup(req);
+    delete ptr;
+}
+
+}
diff --git a/src/storage/file_source.cpp b/src/storage/file_source.cpp
new file mode 100644
index 0000000000..12d924416c
--- /dev/null
+++ b/src/storage/file_source.cpp
@@ -0,0 +1,105 @@
+#include <mbgl/storage/file_source.hpp>
+#include <mbgl/storage/file_request.hpp>
+#include <mbgl/storage/http_request.hpp>
+#include <mbgl/storage/sqlite_store.hpp>
+#include <mbgl/util/uv-messenger.h>
+
+#include <uv.h>
+
+namespace mbgl {
+
+FileSource::FileSource(uv_loop_t *loop_, const std::string &path)
+    : thread_id(uv_thread_self()),
+      store(!path.empty() ? util::ptr<SQLiteStore>(new SQLiteStore(loop_, path)) : nullptr),
+      loop(loop_),
+      queue(new uv_messenger_t) {
+
+    uv_messenger_init(loop, queue, [](void *ptr) {
+        std::unique_ptr<std::function<void()>> fn { reinterpret_cast<std::function<void()> *>(ptr) };
+        (*fn)();
+    });
+    uv_unref((uv_handle_t *)&queue->async);
+}
+
+FileSource::~FileSource() {
+    assert(thread_id == uv_thread_self());
+    uv_messenger_stop(queue);
+    // NOTE: We don't need to delete the messenger since it will be deleted by the
+    // uv_messenger_stop() function.
+
+    util::ptr<BaseRequest> request;
+
+    // Send a cancel() message to all requests that we are still holding.
+    for (const std::pair<std::string, std::weak_ptr<BaseRequest>> &pair : pending) {
+        if ((request = pair.second.lock())) {
+            request->cancel();
+        }
+    }
+}
+
+void FileSource::setBase(const std::string &value) {
+    assert(thread_id == uv_thread_self());
+    base = value;
+}
+
+const std::string &FileSource::getBase() const {
+    assert(thread_id == uv_thread_self());
+    return base;
+}
+
+std::unique_ptr<Request> FileSource::request(ResourceType type, const std::string &url) {
+    assert(thread_id == uv_thread_self());
+
+    // Make URL absolute.
+    const std::string absoluteURL = [&]() -> std::string {
+        const size_t separator = url.find("://");
+        if (separator == std::string::npos) {
+            // Relative URL.
+            return base + url;
+        } else {
+            return url;
+        }
+    }();
+
+    util::ptr<BaseRequest> request;
+
+    // First, try to find an existing Request object.
+    auto it = pending.find(absoluteURL);
+    if (it != pending.end()) {
+        request = it->second.lock();
+    }
+
+    if (!request) {
+        if (absoluteURL.substr(0, 7) == "file://") {
+            request = std::make_shared<FileRequest>(absoluteURL.substr(7), loop);
+        } else {
+            request = std::make_shared<HTTPRequest>(type, absoluteURL, loop, store);
+        }
+
+        pending.emplace(absoluteURL, request);
+    }
+
+    return std::unique_ptr<Request>(new Request(request));
+}
+
+void FileSource::prepare(std::function<void()> fn) {
+    if (thread_id == uv_thread_self()) {
+        fn();
+    } else {
+        uv_messenger_send(queue, new std::function<void()>(std::move(fn)));
+    }
+}
+
+void FileSource::retryAllPending() {
+    assert(thread_id == uv_thread_self());
+
+    util::ptr<BaseRequest> request;
+    for (const std::pair<std::string, std::weak_ptr<BaseRequest>> &pair : pending) {
+        if ((request = pair.second.lock())) {
+            request->retryImmediately();
+        }
+    }
+
+}
+
+}
\ No newline at end of file
diff --git a/src/storage/http_request.cpp b/src/storage/http_request.cpp
new file mode 100644
index 0000000000..1b799d4895
--- /dev/null
+++ b/src/storage/http_request.cpp
@@ -0,0 +1,270 @@
+#include <mbgl/storage/http_request.hpp>
+#include <mbgl/storage/sqlite_store.hpp>
+#include <mbgl/storage/http_request_baton.hpp>
+
+#include <uv.h>
+
+#include <cassert>
+#include <chrono>
+
+namespace mbgl {
+
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdisabled-macro-expansion"
+#pragma clang diagnostic ignored "-Wexit-time-destructors"
+#pragma clang diagnostic ignored "-Wglobal-constructors"
+
+struct CacheRequestBaton {
+    HTTPRequest *request = nullptr;
+    std::string path;
+    util::ptr<SQLiteStore> store;
+};
+
+HTTPRequest::HTTPRequest(ResourceType type_, const std::string &path, uv_loop_t *loop_, util::ptr<SQLiteStore> store_)
+    : BaseRequest(path), thread_id(uv_thread_self()), loop(loop_), store(store_), type(type_) {
+    if (store) {
+        startCacheRequest();
+    } else {
+        startHTTPRequest(nullptr);
+    }
+}
+
+void HTTPRequest::startCacheRequest() {
+    assert(uv_thread_self() == thread_id);
+
+    cache_baton = new CacheRequestBaton;
+    cache_baton->request = this;
+    cache_baton->path = path;
+    cache_baton->store = store;
+    store->get(path, [](std::unique_ptr<Response> &&response, void *ptr) {
+        // Wrap in a unique_ptr, so it'll always get auto-destructed.
+        std::unique_ptr<CacheRequestBaton> baton((CacheRequestBaton *)ptr);
+        if (baton->request) {
+            baton->request->cache_baton = nullptr;
+            baton->request->handleCacheResponse(std::move(response));
+        }
+    }, cache_baton);
+}
+
+void HTTPRequest::handleCacheResponse(std::unique_ptr<Response> &&res) {
+    assert(uv_thread_self() == thread_id);
+
+    if (res) {
+        // This entry was stored in the cache. Now determine if we need to revalidate.
+        const int64_t now = std::chrono::duration_cast<std::chrono::seconds>(
+                                std::chrono::system_clock::now().time_since_epoch()).count();
+        if (res->expires > now) {
+            response = std::move(res);
+            notify();
+            // Note: after calling notify(), the request object may cease to exist.
+            // This HTTPRequest is completed.
+            return;
+        } else {
+            // TODO: notify with preliminary results.
+        }
+    }
+
+    startHTTPRequest(std::move(res));
+}
+
+void HTTPRequest::startHTTPRequest(std::unique_ptr<Response> &&res) {
+    assert(uv_thread_self() == thread_id);
+    assert(!http_baton);
+
+    http_baton = std::make_shared<HTTPRequestBaton>(path);
+    http_baton->request = this;
+    http_baton->async = new uv_async_t;
+    http_baton->response = std::move(res);
+    http_baton->async->data = new util::ptr<HTTPRequestBaton>(http_baton);
+
+    uv_async_init(loop, http_baton->async, [](uv_async_t *async) {
+        util::ptr<HTTPRequestBaton> &http_baton = *(util::ptr<HTTPRequestBaton> *)async->data;
+
+        if (http_baton->request) {
+            HTTPRequest *request = http_baton->request;
+            request->http_baton.reset();
+            http_baton->request = nullptr;
+            request->handleHTTPResponse(http_baton->type, std::move(http_baton->response));
+        }
+
+        delete (util::ptr<HTTPRequestBaton> *)async->data;
+        uv_close((uv_handle_t *)async, [](uv_handle_t *handle) {
+            uv_async_t *async = (uv_async_t *)handle;
+            delete async;
+        });
+    });
+    attempts++;
+    HTTPRequestBaton::start(http_baton);
+}
+
+
+
+void HTTPRequest::handleHTTPResponse(HTTPResponseType responseType, std::unique_ptr<Response> &&res) {
+    assert(uv_thread_self() == thread_id);
+    assert(!http_baton);
+    assert(!response);
+
+    switch (responseType) {
+        // This error was caused by a temporary error and it is likely that it will be resolved
+        // immediately. We are going to try again right away. This is like the TemporaryError,
+        // except that we will not perform exponential back-off.
+        case HTTPResponseType::SingularError:
+            if (attempts >= 4) {
+                // Report as error after 4 attempts.
+                response = std::move(res);
+                notify();
+            } else if (attempts >= 2) {
+                // Switch to the back-off algorithm after the second failure.
+                retryHTTPRequest(std::move(res), (1 << attempts) * 1000);
+                return;
+            } else {
+                startHTTPRequest(std::move(res));
+            }
+            break;
+
+        // This error might be resolved by waiting some time (e.g. server issues).
+        // We are going to do an exponential back-off and will try again in a few seconds.
+        case HTTPResponseType::TemporaryError:
+            if (attempts >= 4) {
+                // Report error back after it failed completely.
+                response = std::move(res);
+                notify();
+            } else {
+                retryHTTPRequest(std::move(res), (1 << attempts) * 1000);
+            }
+            break;
+
+        // This error might be resolved once the network reachability status changes.
+        // We are going to watch the network status for changes and will retry as soon as the
+        // operating system notifies us of a network status change.
+        case HTTPResponseType::ConnectionError:
+
+            if (attempts >= 4) {
+                // Report error back after it failed completely.
+                response = std::move(res);
+                notify();
+            } else {
+                // By default, we will retry every 60 seconds.
+                retryHTTPRequest(std::move(res), 60000);
+            }
+            break;
+
+        // The request was canceled programatically.
+        case HTTPResponseType::Canceled:
+            response.reset();
+            notify();
+            break;
+
+        // This error probably won't be resolved by retrying anytime soon. We are giving up.
+        case HTTPResponseType::PermanentError:
+            response = std::move(res);
+            notify();
+            break;
+
+        // The request returned data successfully. We retrieved and decoded the data successfully.
+        case HTTPResponseType::Successful:
+            if (store) {
+                store->put(path, type, *res);
+            }
+            response = std::move(res);
+            notify();
+            break;
+
+        // The request confirmed that the data wasn't changed. We already have the data.
+        case HTTPResponseType::NotModified:
+            if (store) {
+                store->updateExpiration(path, res->expires);
+            }
+            response = std::move(res);
+            notify();
+            break;
+
+        default:
+            assert(!"Response wasn't set");
+            break;
+    }
+}
+
+using RetryBaton = std::pair<HTTPRequest *, std::unique_ptr<Response>>;
+
+void HTTPRequest::retryHTTPRequest(std::unique_ptr<Response> &&res, uint64_t timeout) {
+    assert(uv_thread_self() == thread_id);
+    assert(!backoff_timer);
+    backoff_timer = new uv_timer_t();
+    uv_timer_init(loop, backoff_timer);
+    backoff_timer->data = new RetryBaton(this, std::move(res));
+    uv_timer_start(backoff_timer, [](uv_timer_t *timer) {
+        std::unique_ptr<RetryBaton> pair { static_cast<RetryBaton *>(timer->data) };
+        pair->first->startHTTPRequest(std::move(pair->second));
+        pair->first->backoff_timer = nullptr;
+        uv_timer_stop(timer);
+        uv_close((uv_handle_t *)timer, [](uv_handle_t *handle) { delete (uv_timer_t *)handle; });
+    }, timeout, 0);
+}
+
+void HTTPRequest::removeHTTPBaton() {
+    assert(uv_thread_self() == thread_id);
+    if (http_baton) {
+        http_baton->request = nullptr;
+        HTTPRequestBaton::stop(http_baton);
+        http_baton.reset();
+    }
+}
+
+void HTTPRequest::removeCacheBaton() {
+    assert(uv_thread_self() == thread_id);
+    if (cache_baton) {
+        // Make sre that this object doesn't accidentally get accessed when it is destructed before
+        // the callback returned. They are being run in the same thread, so just setting it to
+        // null is sufficient.
+        // Note: We don't manually delete the CacheRequestBaton since it'll be deleted by the
+        // callback.
+        cache_baton->request = nullptr;
+        cache_baton = nullptr;
+    }
+}
+
+void HTTPRequest::removeBackoffTimer() {
+    assert(uv_thread_self() == thread_id);
+    if (backoff_timer) {
+        delete static_cast<RetryBaton *>(backoff_timer->data);
+        uv_timer_stop(backoff_timer);
+        uv_close((uv_handle_t *)backoff_timer, [](uv_handle_t *handle) { delete (uv_timer_t *)handle; });
+        backoff_timer = nullptr;
+    }
+}
+
+void HTTPRequest::retryImmediately() {
+    assert(uv_thread_self() == thread_id);
+    if (!cache_baton && !http_baton) {
+        if (backoff_timer) {
+            // Retry immediately.
+            uv_timer_stop(backoff_timer);
+            std::unique_ptr<RetryBaton> pair { static_cast<RetryBaton *>(backoff_timer->data) };
+            assert(pair->first == this);
+            startHTTPRequest(std::move(pair->second));
+            uv_close((uv_handle_t *)backoff_timer, [](uv_handle_t *handle) { delete (uv_timer_t *)handle; });
+            backoff_timer = nullptr;
+        } else {
+            assert(!"We should always have a backoff_timer when there are no batons");
+        }
+    }
+}
+
+void HTTPRequest::cancel() {
+    assert(uv_thread_self() == thread_id);
+    removeCacheBaton();
+    removeHTTPBaton();
+    removeBackoffTimer();
+    notify();
+}
+
+
+HTTPRequest::~HTTPRequest() {
+    assert(uv_thread_self() == thread_id);
+    cancel();
+}
+
+#pragma clang diagnostic pop
+
+}
diff --git a/src/storage/http_request_baton.cpp b/src/storage/http_request_baton.cpp
new file mode 100644
index 0000000000..02edae748f
--- /dev/null
+++ b/src/storage/http_request_baton.cpp
@@ -0,0 +1,12 @@
+#include <mbgl/storage/http_request_baton.hpp>
+#include <uv.h>
+
+namespace mbgl {
+
+HTTPRequestBaton::HTTPRequestBaton(const std::string &path_) : thread_id(uv_thread_self()), path(path_) {
+}
+
+HTTPRequestBaton::~HTTPRequestBaton() {
+}
+
+}
diff --git a/src/storage/request.cpp b/src/storage/request.cpp
new file mode 100644
index 0000000000..42bf87a849
--- /dev/null
+++ b/src/storage/request.cpp
@@ -0,0 +1,49 @@
+#include <mbgl/storage/request.hpp>
+#include <mbgl/storage/base_request.hpp>
+
+#include <uv.h>
+
+#include <cassert>
+
+namespace mbgl {
+
+Request::Request(const util::ptr<BaseRequest> &base_)
+    : thread_id(uv_thread_self()), base(base_) {
+}
+
+Request::~Request() {
+    assert(thread_id == uv_thread_self());
+}
+
+void Request::onload(CompletedCallback cb) {
+    assert(thread_id == uv_thread_self());
+    if (base) {
+        Callback *callback = base->add(std::move(cb), base);
+        if (callback) {
+            callbacks.push_front(callback);
+        }
+    }
+}
+
+void Request::oncancel(AbortedCallback cb) {
+    assert(thread_id == uv_thread_self());
+    if (base) {
+        Callback *callback = base->add(std::move(cb), base);
+        if (callback) {
+            callbacks.push_front(callback);
+        }
+    }
+}
+
+void Request::cancel() {
+    assert(thread_id == uv_thread_self());
+    if (base) {
+        for (Callback *callback : callbacks) {
+            base->remove(callback);
+        }
+        base.reset();
+    }
+    callbacks.clear();
+}
+
+}
diff --git a/src/storage/response.cpp b/src/storage/response.cpp
new file mode 100644
index 0000000000..cdaf33e4e4
--- /dev/null
+++ b/src/storage/response.cpp
@@ -0,0 +1,22 @@
+#include <mbgl/storage/response.hpp>
+
+#include <chrono>
+
+namespace mbgl {
+
+int64_t Response::parseCacheControl(const char *value) {
+    if (value) {
+        uint64_t seconds = 0;
+        // TODO: cache-control may contain other information as well:
+        // http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.9
+        if (std::sscanf(value, "max-age=%llu", &seconds) == 1) {
+            return std::chrono::duration_cast<std::chrono::seconds>(
+                       std::chrono::system_clock::now().time_since_epoch()).count() +
+                   seconds;
+        }
+    }
+
+    return -1;
+}
+
+}
diff --git a/src/storage/sqlite_store.cpp b/src/storage/sqlite_store.cpp
new file mode 100644
index 0000000000..763100f411
--- /dev/null
+++ b/src/storage/sqlite_store.cpp
@@ -0,0 +1,227 @@
+#include <mbgl/storage/sqlite_store.hpp>
+#include <mbgl/util/compression.hpp>
+#include <mbgl/util/sqlite3.hpp>
+
+#include <mbgl/util/uv-worker.h>
+
+#include <cassert>
+
+using namespace mapbox::sqlite;
+
+std::string removeAccessTokenFromURL(const std::string &url) {
+    const size_t token_start = url.find("access_token=");
+    // Ensure that token exists, isn't at the front and is preceded by either & or ?.
+    if (token_start == std::string::npos || token_start == 0 || !(url[token_start - 1] == '&' || url[token_start - 1] == '?')) {
+        return url;
+    }
+
+    const size_t token_end = url.find_first_of('&', token_start);
+    if (token_end == std::string::npos) {
+        // The token is the last query argument. We slice away the "&access_token=..." part
+        return url.substr(0, token_start - 1);
+    } else {
+        // We slice away the "access_token=...&" part.
+        return url.substr(0, token_start) + url.substr(token_end + 1);
+    }
+}
+
+std::string convertMapboxDomainsToProtocol(const std::string &url) {
+    const size_t protocol_separator = url.find("://");
+    if (protocol_separator == std::string::npos) {
+        return url;
+    }
+
+    const std::string protocol = url.substr(0, protocol_separator);
+    if (!(protocol == "http" || protocol == "https")) {
+        return url;
+    }
+
+    const size_t domain_begin = protocol_separator + 3;
+    const size_t path_separator = url.find("/", domain_begin);
+    if (path_separator == std::string::npos) {
+        return url;
+    }
+
+    const std::string domain = url.substr(domain_begin, path_separator - domain_begin);
+    if (domain.find(".tiles.mapbox.com") != std::string::npos) {
+        return "mapbox://" + url.substr(path_separator + 1);
+    } else {
+        return url;
+    }
+}
+
+std::string unifyMapboxURLs(const std::string &url) {
+    return removeAccessTokenFromURL(convertMapboxDomainsToProtocol(url));
+}
+
+namespace mbgl {
+
+SQLiteStore::SQLiteStore(uv_loop_t *loop, const std::string &path)
+    : thread_id(uv_thread_self()),
+      db(std::make_shared<Database>(path.c_str(), ReadWrite | Create)) {
+    createSchema();
+    worker = new uv_worker_t;
+    uv_worker_init(worker, loop, 1, "SQLite");
+}
+
+SQLiteStore::~SQLiteStore() {
+    // Nothing to do. This function needs to be here because we're forward-declaring
+    // Database, so we need the actual definition here to be able to properly destruct it.
+    if (worker) {
+        uv_worker_close(worker, [](uv_worker_t *worker) {
+            delete worker;
+        });
+    }
+}
+
+void SQLiteStore::createSchema() {
+    if (!db || !*db) {
+        return;
+    }
+
+    db->exec("CREATE TABLE IF NOT EXISTS `http_cache` ("
+             "    `url` TEXT PRIMARY KEY NOT NULL,"
+             "    `code` INTEGER NOT NULL,"
+             "    `type` INTEGER NOT NULL,"
+             "    `modified` INTEGER,"
+             "    `etag` TEXT,"
+             "    `expires` INTEGER,"
+             "    `data` BLOB,"
+             "    `compressed` INTEGER NOT NULL DEFAULT 0"
+             ");"
+             "CREATE INDEX IF NOT EXISTS `http_cache_type_idx` ON `http_cache` (`type`);");
+}
+
+struct GetBaton {
+    util::ptr<Database> db;
+    std::string path;
+    ResourceType type;
+    void *ptr = nullptr;
+    SQLiteStore::GetCallback callback = nullptr;
+    std::unique_ptr<Response> response;
+};
+
+void SQLiteStore::get(const std::string &path, GetCallback callback, void *ptr) {
+    assert(uv_thread_self() == thread_id);
+    if (!db || !*db) {
+        if (callback) {
+            callback(nullptr, ptr);
+        }
+        return;
+    }
+
+    GetBaton *get_baton = new GetBaton;
+    get_baton->db = db;
+    get_baton->path = path;
+    get_baton->ptr = ptr;
+    get_baton->callback = callback;
+
+    uv_worker_send(worker, get_baton, [](void *data) {
+        GetBaton *baton = (GetBaton *)data;
+        const std::string url = unifyMapboxURLs(baton->path);
+        //                                                    0       1         2
+        Statement stmt = baton->db->prepare("SELECT `code`, `type`, `modified`, "
+        //     3         4        5           6
+            "`etag`, `expires`, `data`, `compressed` FROM `http_cache` WHERE `url` = ?");
+
+        stmt.bind(1, url.c_str());
+        if (stmt.run()) {
+            // There is data.
+            baton->response = std::unique_ptr<Response>(new Response);
+
+            baton->response->code = stmt.get<int>(0);
+            baton->type = ResourceType(stmt.get<int>(1));
+            baton->response->modified = stmt.get<int64_t>(2);
+            baton->response->etag = stmt.get<std::string>(3);
+            baton->response->expires = stmt.get<int64_t>(4);
+            baton->response->data = stmt.get<std::string>(5);
+            if (stmt.get<int>(6)) { // == compressed
+                baton->response->data = util::decompress(baton->response->data);
+            }
+        } else {
+            // There is no data.
+            // This is a noop.
+        }
+    }, [](void *data) {
+        std::unique_ptr<GetBaton> baton { (GetBaton *)data };
+        if (baton->callback) {
+            baton->callback(std::move(baton->response), baton->ptr);
+        }
+    });
+}
+
+
+struct PutBaton {
+    util::ptr<Database> db;
+    std::string path;
+    ResourceType type;
+    Response response;
+};
+
+void SQLiteStore::put(const std::string &path, ResourceType type, const Response &response) {
+    assert(uv_thread_self() == thread_id);
+    if (!db) return;
+
+    PutBaton *put_baton = new PutBaton;
+    put_baton->db = db;
+    put_baton->path = path;
+    put_baton->type = type;
+    put_baton->response = response;
+
+    uv_worker_send(worker, put_baton, [](void *data) {
+        PutBaton *baton = (PutBaton *)data;
+        const std::string url = unifyMapboxURLs(baton->path);
+        Statement stmt = baton->db->prepare("REPLACE INTO `http_cache` ("
+        //     1      2       3         4         5         6        7          8
+            "`url`, `code`, `type`, `modified`, `etag`, `expires`, `data`, `compressed`"
+            ") VALUES(?, ?, ?, ?, ?, ?, ?, ?)");
+        stmt.bind(1, url.c_str());
+        stmt.bind(2, int(baton->response.code));
+        stmt.bind(3, int(baton->type));
+        stmt.bind(4, baton->response.modified);
+        stmt.bind(5, baton->response.etag.c_str());
+        stmt.bind(6, baton->response.expires);
+
+        if (baton->type == ResourceType::Image) {
+            stmt.bind(7, baton->response.data, false); // do not retain the string internally.
+            stmt.bind(8, false);
+        } else {
+            stmt.bind(7, util::compress(baton->response.data), true); // retain the string internally.
+            stmt.bind(8, true);
+        }
+
+        stmt.run();
+    }, [](void *data) {
+        delete (PutBaton *)data;
+    });
+}
+
+struct ExpirationBaton {
+    util::ptr<Database> db;
+    std::string path;
+    int64_t expires;
+};
+
+void SQLiteStore::updateExpiration(const std::string &path, int64_t expires) {
+    assert(uv_thread_self() == thread_id);
+    if (!db || !*db) return;
+
+    ExpirationBaton *expiration_baton = new ExpirationBaton;
+    expiration_baton->db = db;
+    expiration_baton->path = path;
+    expiration_baton->expires = expires;
+
+    uv_worker_send(worker, expiration_baton, [](void *data) {
+        ExpirationBaton *baton = (ExpirationBaton *)data;
+        const std::string url = unifyMapboxURLs(baton->path);
+        Statement stmt = //                                 1               2
+            baton->db->prepare("UPDATE `http_cache` SET `expires` = ? WHERE `url` = ?");
+        stmt.bind<int64_t>(1, baton->expires);
+        stmt.bind(2, url.c_str());
+        stmt.run();
+    }, [](void *data) {
+        delete (ExpirationBaton *)data;
+    });
+}
+
+}
diff --git a/src/style/style_layer_group.cpp b/src/style/style_layer_group.cpp
index c7e4360d21..a731aebdcb 100644
--- a/src/style/style_layer_group.cpp
+++ b/src/style/style_layer_group.cpp
@@ -5,7 +5,7 @@ namespace mbgl {
 
 void StyleLayerGroup::setClasses(const std::vector<std::string> &class_names, timestamp now,
                                  const PropertyTransition &defaultTransition) {
-    for (const std::shared_ptr<StyleLayer> &layer : layers) {
+    for (const util::ptr<StyleLayer> &layer : layers) {
         if (layer) {
             layer->setClasses(class_names, now, defaultTransition);
         }
@@ -13,7 +13,7 @@ void StyleLayerGroup::setClasses(const std::vector<std::string> &class_names, ti
 }
 
 void StyleLayerGroup::updateProperties(float z, timestamp t) {
-    for (const std::shared_ptr<StyleLayer> &layer: layers) {
+    for (const util::ptr<StyleLayer> &layer: layers) {
         if (layer) {
             layer->updateProperties(z, t);
         }
@@ -21,7 +21,7 @@ void StyleLayerGroup::updateProperties(float z, timestamp t) {
 }
 
 bool StyleLayerGroup::hasTransitions() const {
-    for (const std::shared_ptr<const StyleLayer> &layer: layers) {
+    for (const util::ptr<const StyleLayer> &layer: layers) {
         if (layer) {
             if (layer->hasTransitions()) {
                 return true;
diff --git a/src/style/style_parser.cpp b/src/style/style_parser.cpp
index ad7694d9a9..2a64ab38f8 100644
--- a/src/style/style_parser.cpp
+++ b/src/style/style_parser.cpp
@@ -176,12 +176,12 @@ void StyleParser::parseSources(JSVal value) {
         rapidjson::Value::ConstMemberIterator itr = value.MemberBegin();
         for (; itr != value.MemberEnd(); ++itr) {
             std::string name { itr->name.GetString(), itr->name.GetStringLength() };
-            SourceInfo info;
+            util::ptr<SourceInfo> info = std::make_shared<SourceInfo>();
 
-            parseRenderProperty<SourceTypeClass>(itr->value, info.type, "type");
-            parseRenderProperty(itr->value, info.url, "url");
-            parseRenderProperty(itr->value, info.tile_size, "tileSize");
-            info.parseTileJSONProperties(itr->value);
+            parseRenderProperty<SourceTypeClass>(itr->value, info->type, "type");
+            parseRenderProperty(itr->value, info->url, "url");
+            parseRenderProperty(itr->value, info->tile_size, "tileSize");
+            info->parseTileJSONProperties(itr->value);
 
             sources.emplace(std::move(name), std::make_shared<StyleSource>(info));
         }
@@ -451,7 +451,7 @@ std::unique_ptr<StyleLayerGroup> StyleParser::createLayers(JSVal value) {
     if (value.IsArray()) {
         std::unique_ptr<StyleLayerGroup> group = std::make_unique<StyleLayerGroup>();
         for (rapidjson::SizeType i = 0; i < value.Size(); ++i) {
-            std::shared_ptr<StyleLayer> layer = createLayer(value[i]);
+            util::ptr<StyleLayer> layer = createLayer(value[i]);
             if (layer) {
                 group->layers.emplace_back(layer);
             }
@@ -463,7 +463,7 @@ std::unique_ptr<StyleLayerGroup> StyleParser::createLayers(JSVal value) {
     }
 }
 
-std::shared_ptr<StyleLayer> StyleParser::createLayer(JSVal value) {
+util::ptr<StyleLayer> StyleParser::createLayer(JSVal value) {
     if (value.IsObject()) {
         if (!value.HasMember("id")) {
             Log::Warning(Event::ParseStyle, "layer must have an id");
@@ -487,7 +487,7 @@ std::shared_ptr<StyleLayer> StyleParser::createLayer(JSVal value) {
         std::map<ClassID, ClassProperties> styles;
         parseStyles(value, styles);
 
-        std::shared_ptr<StyleLayer> layer = std::make_shared<StyleLayer>(
+        util::ptr<StyleLayer> layer = std::make_shared<StyleLayer>(
             layer_id, std::move(styles));
 
         if (value.HasMember("layers")) {
@@ -495,7 +495,7 @@ std::shared_ptr<StyleLayer> StyleParser::createLayer(JSVal value) {
         }
 
         // Store the layer ID so we can reference it later.
-        layers.emplace(layer_id, std::pair<JSVal, std::shared_ptr<StyleLayer>> { value, layer });
+        layers.emplace(layer_id, std::pair<JSVal, util::ptr<StyleLayer>> { value, layer });
 
         return layer;
     } else {
@@ -505,14 +505,14 @@ std::shared_ptr<StyleLayer> StyleParser::createLayer(JSVal value) {
 }
 
 void StyleParser::parseLayers() {
-    for (std::pair<const std::string, std::pair<JSVal, std::shared_ptr<StyleLayer>>> &pair : layers) {
+    for (std::pair<const std::string, std::pair<JSVal, util::ptr<StyleLayer>>> &pair : layers) {
         parseLayer(pair.second);
     }
 }
 
-void StyleParser::parseLayer(std::pair<JSVal, std::shared_ptr<StyleLayer>> &pair) {
+void StyleParser::parseLayer(std::pair<JSVal, util::ptr<StyleLayer>> &pair) {
     JSVal value = pair.first;
-    std::shared_ptr<StyleLayer> &layer = pair.second;
+    util::ptr<StyleLayer> &layer = pair.second;
 
     if (value.HasMember("type")) {
         JSVal type = value["type"];
@@ -642,7 +642,7 @@ void StyleParser::parseStyle(JSVal value, ClassProperties &klass) {
     parseOptionalProperty<Function<Color>>("background-color", Key::BackgroundColor, klass, value);
 }
 
-void StyleParser::parseReference(JSVal value, std::shared_ptr<StyleLayer> &layer) {
+void StyleParser::parseReference(JSVal value, util::ptr<StyleLayer> &layer) {
     if (!value.IsString()) {
         Log::Warning(Event::ParseStyle, "layer ref of '%s' must be a string", layer->id.c_str());
         return;
@@ -661,7 +661,7 @@ void StyleParser::parseReference(JSVal value, std::shared_ptr<StyleLayer> &layer
     stack.pop_front();
 
 
-    std::shared_ptr<StyleLayer> reference = it->second.second;
+    util::ptr<StyleLayer> reference = it->second.second;
 
     layer->type = reference->type;
 
@@ -676,7 +676,7 @@ void StyleParser::parseReference(JSVal value, std::shared_ptr<StyleLayer> &layer
 
 #pragma mark - Parse Bucket
 
-void StyleParser::parseBucket(JSVal value, std::shared_ptr<StyleLayer> &layer) {
+void StyleParser::parseBucket(JSVal value, util::ptr<StyleLayer> &layer) {
     layer->bucket = std::make_shared<StyleBucket>(layer->type);
 
     // We name the buckets according to the layer that defined it.
@@ -822,7 +822,7 @@ std::vector<Value> StyleParser::parseValues(JSVal value) {
     return values;
 }
 
-void StyleParser::parseRender(JSVal value, std::shared_ptr<StyleLayer> &layer) {
+void StyleParser::parseRender(JSVal value, util::ptr<StyleLayer> &layer) {
     if (!value.IsObject()) {
         Log::Warning(Event::ParseStyle, "render property of layer '%s' must be an object", layer->id.c_str());
         return;
diff --git a/src/text/glyph.cpp b/src/text/glyph.cpp
index 7dea7246d7..f02c710db2 100644
--- a/src/text/glyph.cpp
+++ b/src/text/glyph.cpp
@@ -3,9 +3,6 @@
 namespace mbgl {
 
 // Note: this only works for the BMP
-// Note: we could use a binary lookup table to get averaged constant time lookups, however,
-// most of our lookups are going to be within the first 3 ranges listed here, so this is
-// likely faster.
 GlyphRange getGlyphRange(char32_t glyph) {
     unsigned start = (glyph/256) * 256;
     unsigned end = (start + 255);
diff --git a/src/text/glyph_store.cpp b/src/text/glyph_store.cpp
index 783710d929..1723bd3d94 100644
--- a/src/text/glyph_store.cpp
+++ b/src/text/glyph_store.cpp
@@ -8,7 +8,7 @@
 #include <mbgl/util/constants.hpp>
 #include <mbgl/util/token.hpp>
 #include <mbgl/util/math.hpp>
-#include <mbgl/util/filesource.hpp>
+#include <mbgl/storage/file_source.hpp>
 #include <mbgl/platform/platform.hpp>
 #include <mbgl/util/uv_detail.hpp>
 #include <algorithm>
@@ -137,7 +137,7 @@ void FontStack::lineWrap(Shaping &shaping, const float lineHeight, const float m
     align(shaping, justify, horizontalAlign, verticalAlign, maxLineLength, lineHeight, line);
 }
 
-GlyphPBF::GlyphPBF(const std::string &glyphURL, const std::string &fontStack, GlyphRange glyphRange, const std::shared_ptr<FileSource> &fileSource)
+GlyphPBF::GlyphPBF(const std::string &glyphURL, const std::string &fontStack, GlyphRange glyphRange, const util::ptr<FileSource> &fileSource)
     : future(promise.get_future().share())
 {
     // Load the glyph set URL
@@ -147,23 +147,26 @@ GlyphPBF::GlyphPBF(const std::string &glyphURL, const std::string &fontStack, Gl
         return "";
     });
 
-#if defined(DEBUG)
-    fprintf(stderr, "%s\n", url.c_str());
-#endif
-
-    fileSource->load(ResourceType::Glyphs, url, [&](platform::Response *res) {
-        if (res->code != 200) {
-            // Something went wrong with loading the glyph pbf. Pass on the error to the future listeners.
-            const std::string msg = util::sprintf<255>("[ERROR] failed to load glyphs (%d): %s\n", res->code, res->error_message.c_str());
-            promise.set_exception(std::make_exception_ptr(std::runtime_error(msg)));
-        } else {
-            // Transfer the data to the GlyphSet and signal its availability.
-            // Once it is available, the caller will need to call parse() to actually
-            // parse the data we received. We are not doing this here since this callback is being
-            // called from another (unknown) thread.
-            data.swap(res->body);
-            promise.set_value(*this);
-        }
+    // The prepare call jumps back to the main thread.
+    fileSource->prepare([&, url, fileSource] {
+        auto request = fileSource->request(ResourceType::Glyphs, url);
+        request->onload([&, url](const Response &res) {
+            if (res.code != 200) {
+                // Something went wrong with loading the glyph pbf. Pass on the error to the future listeners.
+                const std::string msg = util::sprintf<255>("[ERROR] failed to load glyphs (%d): %s\n", res.code, res.message.c_str());
+                promise.set_exception(std::make_exception_ptr(std::runtime_error(msg)));
+            } else {
+                // Transfer the data to the GlyphSet and signal its availability.
+                // Once it is available, the caller will need to call parse() to actually
+                // parse the data we received. We are not doing this here since this callback is being
+                // called from another (unknown) thread.
+                data = res.data;
+                promise.set_value(*this);
+            }
+        });
+        request->oncancel([&]() {
+            promise.set_exception(std::make_exception_ptr(std::runtime_error("Loading glyphs was canceled")));
+        });
     });
 }
 
@@ -225,7 +228,7 @@ void GlyphPBF::parse(FontStack &stack) {
     data.clear();
 }
 
-GlyphStore::GlyphStore(const std::shared_ptr<FileSource> &fileSource) : fileSource(fileSource) {}
+GlyphStore::GlyphStore(const util::ptr<FileSource> &fileSource) : fileSource(fileSource) {}
 
 void GlyphStore::setURL(const std::string &url) {
     glyphURL = url;
diff --git a/src/util/compression.cpp b/src/util/compression.cpp
new file mode 100644
index 0000000000..de4e09764c
--- /dev/null
+++ b/src/util/compression.cpp
@@ -0,0 +1,81 @@
+#include <mbgl/util/compression.hpp>
+
+#include <zlib.h>
+
+#include <cstring>
+#include <stdexcept>
+
+namespace mbgl {
+namespace util {
+
+std::string compress(const std::string &raw) {
+    z_stream deflate_stream;
+    memset(&deflate_stream, 0, sizeof(deflate_stream));
+
+    // TODO: reuse z_streams
+    if (deflateInit(&deflate_stream, Z_DEFAULT_COMPRESSION) != Z_OK) {
+        throw std::runtime_error("failed to initialize deflate");
+    }
+
+    deflate_stream.next_in = (Bytef *)raw.data();
+    deflate_stream.avail_in = raw.size();
+
+    std::string result;
+    char out[16384];
+
+    int code;
+    do {
+        deflate_stream.next_out = reinterpret_cast<Bytef *>(out);
+        deflate_stream.avail_out = sizeof(out);
+        code = deflate(&deflate_stream, Z_FINISH);
+        if (result.size() < deflate_stream.total_out) {
+            // append the block to the output string
+            result.append(out, deflate_stream.total_out - result.size());
+        }
+    } while (code == Z_OK);
+
+    deflateEnd(&deflate_stream);
+
+    if (code != Z_STREAM_END) {
+        throw std::runtime_error(deflate_stream.msg);
+    }
+
+    return result;
+}
+
+std::string decompress(const std::string &raw) {
+    z_stream inflate_stream;
+    memset(&inflate_stream, 0, sizeof(inflate_stream));
+
+    // TODO: reuse z_streams
+    if (inflateInit(&inflate_stream) != Z_OK) {
+        throw std::runtime_error("failed to initialize inflate");
+    }
+
+    inflate_stream.next_in = (Bytef *)raw.data();
+    inflate_stream.avail_in = raw.size();
+
+    std::string result;
+    char out[15384];
+
+    int code;
+    do {
+        inflate_stream.next_out = reinterpret_cast<Bytef *>(out);
+        inflate_stream.avail_out = sizeof(out);
+        code = inflate(&inflate_stream, 0);
+        // result.append(out, sizeof(out) - inflate_stream.avail_out);
+        if (result.size() < inflate_stream.total_out) {
+            result.append(out, inflate_stream.total_out - result.size());
+        }
+    } while (code == Z_OK);
+
+    inflateEnd(&inflate_stream);
+
+    if (code != Z_STREAM_END) {
+        throw std::runtime_error(inflate_stream.msg);
+    }
+
+    return result;
+}
+}
+}
diff --git a/src/util/filesource.cpp b/src/util/filesource.cpp
deleted file mode 100644
index 503d4dfb1d..0000000000
--- a/src/util/filesource.cpp
+++ /dev/null
@@ -1,58 +0,0 @@
-#include <mbgl/util/filesource.hpp>
-#include <mbgl/platform/platform.hpp>
-
-#include <fstream>
-#include <sstream>
-
-namespace mbgl {
-
-FileSource::FileSource() {}
-
-
-void FileSource::setBase(const std::string &value) {
-    base = value;
-}
-
-const std::string &FileSource::getBase() const {
-    return base;
-}
-
-void FileSource::load(ResourceType /*type*/, const std::string &url, std::function<void(platform::Response *)> callback, const std::shared_ptr<uv::loop> loop) {
-    // convert relative URLs to absolute URLs
-
-    const std::string absoluteURL = [&]() -> std::string {
-        const size_t separator = url.find("://");
-        if (separator == std::string::npos) {
-            // Relative URL.
-            return base + url;
-        } else {
-            return url;
-        }
-    }();
-
-    const size_t separator = absoluteURL.find("://");
-    const std::string protocol = separator != std::string::npos ? absoluteURL.substr(0, separator) : "";
-
-    if (protocol == "file") {
-        // load from disk
-        const std::string path = absoluteURL.substr(separator + 3);
-        std::ifstream file(path);
-
-        platform::Response response(callback);
-        if (!file.good()) {
-            response.error_message = "file not found (" + path + ")";
-        } else {
-            std::stringstream data;
-            data << file.rdbuf();
-            response.code = 200;
-            response.body = data.str();
-        }
-
-        callback(&response);
-    } else {
-        // load from the internet
-        platform::request_http(absoluteURL, callback, loop);
-    }
-}
-
-}
\ No newline at end of file
diff --git a/src/util/parsedate.c b/src/util/parsedate.c
new file mode 100644
index 0000000000..123c5c4e5f
--- /dev/null
+++ b/src/util/parsedate.c
@@ -0,0 +1,689 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2014, Daniel Stenberg, <daniel@haxx.se>, et al.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at http://curl.haxx.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ***************************************************************************/
+/*
+  A brief summary of the date string formats this parser groks:
+
+  RFC 2616 3.3.1
+
+  Sun, 06 Nov 1994 08:49:37 GMT  ; RFC 822, updated by RFC 1123
+  Sunday, 06-Nov-94 08:49:37 GMT ; RFC 850, obsoleted by RFC 1036
+  Sun Nov  6 08:49:37 1994       ; ANSI C's asctime() format
+
+  we support dates without week day name:
+
+  06 Nov 1994 08:49:37 GMT
+  06-Nov-94 08:49:37 GMT
+  Nov  6 08:49:37 1994
+
+  without the time zone:
+
+  06 Nov 1994 08:49:37
+  06-Nov-94 08:49:37
+
+  weird order:
+
+  1994 Nov 6 08:49:37  (GNU date fails)
+  GMT 08:49:37 06-Nov-94 Sunday
+  94 6 Nov 08:49:37    (GNU date fails)
+
+  time left out:
+
+  1994 Nov 6
+  06-Nov-94
+  Sun Nov 6 94
+
+  unusual separators:
+
+  1994.Nov.6
+  Sun/Nov/6/94/GMT
+
+  commonly used time zone names:
+
+  Sun, 06 Nov 1994 08:49:37 CET
+  06 Nov 1994 08:49:37 EST
+
+  time zones specified using RFC822 style:
+
+  Sun, 12 Sep 2004 15:05:58 -0700
+  Sat, 11 Sep 2004 21:32:11 +0200
+
+  compact numerical date strings:
+
+  20040912 15:05:58 -0700
+  20040911 +0200
+
+*/
+
+#include <mbgl/util/parsedate.h>
+
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <limits.h>
+#include <stdbool.h>
+#include <errno.h>
+#include <string.h>
+#include <ctype.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+
+#define ERRNO         (errno)
+#define SET_ERRNO(x)  (errno = (x))
+
+
+/* Portable, consistent toupper (remember EBCDIC). Do not use toupper() because
+   its behavior is altered by the current locale. */
+char raw_toupper(char in)
+{
+  switch (in) {
+  case 'a':
+    return 'A';
+  case 'b':
+    return 'B';
+  case 'c':
+    return 'C';
+  case 'd':
+    return 'D';
+  case 'e':
+    return 'E';
+  case 'f':
+    return 'F';
+  case 'g':
+    return 'G';
+  case 'h':
+    return 'H';
+  case 'i':
+    return 'I';
+  case 'j':
+    return 'J';
+  case 'k':
+    return 'K';
+  case 'l':
+    return 'L';
+  case 'm':
+    return 'M';
+  case 'n':
+    return 'N';
+  case 'o':
+    return 'O';
+  case 'p':
+    return 'P';
+  case 'q':
+    return 'Q';
+  case 'r':
+    return 'R';
+  case 's':
+    return 'S';
+  case 't':
+    return 'T';
+  case 'u':
+    return 'U';
+  case 'v':
+    return 'V';
+  case 'w':
+    return 'W';
+  case 'x':
+    return 'X';
+  case 'y':
+    return 'Y';
+  case 'z':
+    return 'Z';
+  }
+  return in;
+}
+
+/*
+ * raw_equal() is for doing "raw" case insensitive strings. This is meant
+ * to be locale independent and only compare strings we know are safe for
+ * this.  See http://daniel.haxx.se/blog/2008/10/15/strcasecmp-in-turkish/ for
+ * some further explanation to why this function is necessary.
+ *
+ * The function is capable of comparing a-z case insensitively even for
+ * non-ascii.
+ */
+
+int raw_equal(const char *first, const char *second)
+{
+  while(*first && *second) {
+    if(raw_toupper(*first) != raw_toupper(*second))
+      /* get out of the loop as soon as they don't match */
+      break;
+    first++;
+    second++;
+  }
+  /* we do the comparison here (possibly again), just to make sure that if the
+     loop above is skipped because one of the strings reached zero, we must not
+     return this as a successful match */
+  return (raw_toupper(*first) == raw_toupper(*second));
+}
+
+#define ISSPACE(x)  (isspace((int)  ((unsigned char)x)))
+#define ISDIGIT(x)  (isdigit((int)  ((unsigned char)x)))
+#define ISALNUM(x)  (isalnum((int)  ((unsigned char)x)))
+#define ISALPHA(x)  (isalpha((int)  ((unsigned char)x)))
+
+
+/*
+ * Redefine TRUE and FALSE too, to catch current use. With this
+ * change, 'bool found = 1' will give a warning on MIPSPro, but
+ * 'bool found = TRUE' will not. Change tested on IRIX/MIPSPro,
+ * AIX 5.1/Xlc, Tru64 5.1/cc, w/make test too.
+ */
+
+#ifndef TRUE
+#define TRUE true
+#endif
+#ifndef FALSE
+#define FALSE false
+#endif
+
+
+
+/*
+** signed long to signed int
+*/
+
+int clamp_to_int(long slnum)
+{
+  return slnum > INT_MAX ? INT_MAX : slnum < INT_MIN ? INT_MIN : slnum;
+}
+
+
+const char * const wkday[] =
+{"Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"};
+static const char * const weekday[] =
+{ "Monday", "Tuesday", "Wednesday", "Thursday",
+  "Friday", "Saturday", "Sunday" };
+const char * const month[]=
+{ "Jan", "Feb", "Mar", "Apr", "May", "Jun",
+  "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" };
+
+struct tzinfo {
+  char name[5];
+  int offset; /* +/- in minutes */
+};
+
+/*
+ * parsedate()
+ *
+ * Returns:
+ *
+ * PARSEDATE_OK     - a fine conversion
+ * PARSEDATE_FAIL   - failed to convert
+ * PARSEDATE_LATER  - time overflow at the far end of time_t
+ * PARSEDATE_SOONER - time underflow at the low end of time_t
+ */
+
+static int parsedate(const char *date, time_t *output);
+
+#define PARSEDATE_OK     0
+#define PARSEDATE_FAIL   -1
+#define PARSEDATE_LATER  1
+#define PARSEDATE_SOONER 2
+
+/* Here's a bunch of frequently used time zone names. These were supported
+   by the old getdate parser. */
+#define tDAYZONE -60       /* offset for daylight savings time */
+static const struct tzinfo tz[]= {
+  {"GMT", 0},              /* Greenwich Mean */
+  {"UTC", 0},              /* Universal (Coordinated) */
+  {"WET", 0},              /* Western European */
+  {"BST", 0 tDAYZONE},     /* British Summer */
+  {"WAT", 60},             /* West Africa */
+  {"AST", 240},            /* Atlantic Standard */
+  {"ADT", 240 tDAYZONE},   /* Atlantic Daylight */
+  {"EST", 300},            /* Eastern Standard */
+  {"EDT", 300 tDAYZONE},   /* Eastern Daylight */
+  {"CST", 360},            /* Central Standard */
+  {"CDT", 360 tDAYZONE},   /* Central Daylight */
+  {"MST", 420},            /* Mountain Standard */
+  {"MDT", 420 tDAYZONE},   /* Mountain Daylight */
+  {"PST", 480},            /* Pacific Standard */
+  {"PDT", 480 tDAYZONE},   /* Pacific Daylight */
+  {"YST", 540},            /* Yukon Standard */
+  {"YDT", 540 tDAYZONE},   /* Yukon Daylight */
+  {"HST", 600},            /* Hawaii Standard */
+  {"HDT", 600 tDAYZONE},   /* Hawaii Daylight */
+  {"CAT", 600},            /* Central Alaska */
+  {"AHST", 600},           /* Alaska-Hawaii Standard */
+  {"NT",  660},            /* Nome */
+  {"IDLW", 720},           /* International Date Line West */
+  {"CET", -60},            /* Central European */
+  {"MET", -60},            /* Middle European */
+  {"MEWT", -60},           /* Middle European Winter */
+  {"MEST", -60 tDAYZONE},  /* Middle European Summer */
+  {"CEST", -60 tDAYZONE},  /* Central European Summer */
+  {"MESZ", -60 tDAYZONE},  /* Middle European Summer */
+  {"FWT", -60},            /* French Winter */
+  {"FST", -60 tDAYZONE},   /* French Summer */
+  {"EET", -120},           /* Eastern Europe, USSR Zone 1 */
+  {"WAST", -420},          /* West Australian Standard */
+  {"WADT", -420 tDAYZONE}, /* West Australian Daylight */
+  {"CCT", -480},           /* China Coast, USSR Zone 7 */
+  {"JST", -540},           /* Japan Standard, USSR Zone 8 */
+  {"EAST", -600},          /* Eastern Australian Standard */
+  {"EADT", -600 tDAYZONE}, /* Eastern Australian Daylight */
+  {"GST", -600},           /* Guam Standard, USSR Zone 9 */
+  {"NZT", -720},           /* New Zealand */
+  {"NZST", -720},          /* New Zealand Standard */
+  {"NZDT", -720 tDAYZONE}, /* New Zealand Daylight */
+  {"IDLE", -720},          /* International Date Line East */
+  /* Next up: Military timezone names. RFC822 allowed these, but (as noted in
+     RFC 1123) had their signs wrong. Here we use the correct signs to match
+     actual military usage.
+   */
+  {"A",  +1 * 60},         /* Alpha */
+  {"B",  +2 * 60},         /* Bravo */
+  {"C",  +3 * 60},         /* Charlie */
+  {"D",  +4 * 60},         /* Delta */
+  {"E",  +5 * 60},         /* Echo */
+  {"F",  +6 * 60},         /* Foxtrot */
+  {"G",  +7 * 60},         /* Golf */
+  {"H",  +8 * 60},         /* Hotel */
+  {"I",  +9 * 60},         /* India */
+  /* "J", Juliet is not used as a timezone, to indicate the observer's local
+     time */
+  {"K", +10 * 60},         /* Kilo */
+  {"L", +11 * 60},         /* Lima */
+  {"M", +12 * 60},         /* Mike */
+  {"N",  -1 * 60},         /* November */
+  {"O",  -2 * 60},         /* Oscar */
+  {"P",  -3 * 60},         /* Papa */
+  {"Q",  -4 * 60},         /* Quebec */
+  {"R",  -5 * 60},         /* Romeo */
+  {"S",  -6 * 60},         /* Sierra */
+  {"T",  -7 * 60},         /* Tango */
+  {"U",  -8 * 60},         /* Uniform */
+  {"V",  -9 * 60},         /* Victor */
+  {"W", -10 * 60},         /* Whiskey */
+  {"X", -11 * 60},         /* X-ray */
+  {"Y", -12 * 60},         /* Yankee */
+  {"Z", 0},                /* Zulu, zero meridian, a.k.a. UTC */
+};
+
+/* returns:
+   -1 no day
+   0 monday - 6 sunday
+*/
+
+static int checkday(const char *check, size_t len)
+{
+  int i;
+  const char * const *what;
+  bool found= FALSE;
+  if(len > 3)
+    what = &weekday[0];
+  else
+    what = &wkday[0];
+  for(i=0; i<7; i++) {
+    if(raw_equal(check, what[0])) {
+      found=TRUE;
+      break;
+    }
+    what++;
+  }
+  return found?i:-1;
+}
+
+static int checkmonth(const char *check)
+{
+  int i;
+  const char * const *what;
+  bool found= FALSE;
+
+  what = &month[0];
+  for(i=0; i<12; i++) {
+    if(raw_equal(check, what[0])) {
+      found=TRUE;
+      break;
+    }
+    what++;
+  }
+  return found?i:-1; /* return the offset or -1, no real offset is -1 */
+}
+
+/* return the time zone offset between GMT and the input one, in number
+   of seconds or -1 if the timezone wasn't found/legal */
+
+static int checktz(const char *check)
+{
+  unsigned int i;
+  const struct tzinfo *what;
+  bool found= FALSE;
+
+  what = tz;
+  for(i=0; i< sizeof(tz)/sizeof(tz[0]); i++) {
+    if(raw_equal(check, what->name)) {
+      found=TRUE;
+      break;
+    }
+    what++;
+  }
+  return found?what->offset*60:-1;
+}
+
+static void skip(const char **date)
+{
+  /* skip everything that aren't letters or digits */
+  while(**date && !ISALNUM(**date))
+    (*date)++;
+}
+
+enum assume {
+  DATE_MDAY,
+  DATE_YEAR,
+  DATE_TIME
+};
+
+/* this is a clone of 'struct tm' but with all fields we don't need or use
+   cut out */
+struct my_tm {
+  int tm_sec;
+  int tm_min;
+  int tm_hour;
+  int tm_mday;
+  int tm_mon;
+  int tm_year;
+};
+
+/* struct tm to time since epoch in GMT time zone.
+ * This is similar to the standard mktime function but for GMT only, and
+ * doesn't suffer from the various bugs and portability problems that
+ * some systems' implementations have.
+ */
+static time_t my_timegm(struct my_tm *tm)
+{
+  static const int month_days_cumulative [12] =
+    { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
+  int month, year, leap_days;
+
+  if(tm->tm_year < 70)
+    /* we don't support years before 1970 as they will cause this function
+       to return a negative value */
+    return -1;
+
+  year = tm->tm_year + 1900;
+  month = tm->tm_mon;
+  if(month < 0) {
+    year += (11 - month) / 12;
+    month = 11 - (11 - month) % 12;
+  }
+  else if(month >= 12) {
+    year -= month / 12;
+    month = month % 12;
+  }
+
+  leap_days = year - (tm->tm_mon <= 1);
+  leap_days = ((leap_days / 4) - (leap_days / 100) + (leap_days / 400)
+               - (1969 / 4) + (1969 / 100) - (1969 / 400));
+
+  return ((((time_t) (year - 1970) * 365
+            + leap_days + month_days_cumulative [month] + tm->tm_mday - 1) * 24
+           + tm->tm_hour) * 60 + tm->tm_min) * 60 + tm->tm_sec;
+}
+
+/*
+ * parsedate()
+ *
+ * Returns:
+ *
+ * PARSEDATE_OK     - a fine conversion
+ * PARSEDATE_FAIL   - failed to convert
+ * PARSEDATE_LATER  - time overflow at the far end of time_t
+ * PARSEDATE_SOONER - time underflow at the low end of time_t
+ */
+
+static int parsedate(const char *date, time_t *output)
+{
+  time_t t = 0;
+  int wdaynum=-1;  /* day of the week number, 0-6 (mon-sun) */
+  int monnum=-1;   /* month of the year number, 0-11 */
+  int mdaynum=-1; /* day of month, 1 - 31 */
+  int hournum=-1;
+  int minnum=-1;
+  int secnum=-1;
+  int yearnum=-1;
+  int tzoff=-1;
+  struct my_tm tm;
+  enum assume dignext = DATE_MDAY;
+  const char *indate = date; /* save the original pointer */
+  int part = 0; /* max 6 parts */
+
+  while(*date && (part < 6)) {
+    bool found=FALSE;
+
+    skip(&date);
+
+    if(ISALPHA(*date)) {
+      /* a name coming up */
+      char buf[32]="";
+      size_t len;
+      if(sscanf(date, "%31[ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+                          "abcdefghijklmnopqrstuvwxyz]", buf))
+        len = strlen(buf);
+      else
+        len = 0;
+
+      if(wdaynum == -1) {
+        wdaynum = checkday(buf, len);
+        if(wdaynum != -1)
+          found = TRUE;
+      }
+      if(!found && (monnum == -1)) {
+        monnum = checkmonth(buf);
+        if(monnum != -1)
+          found = TRUE;
+      }
+
+      if(!found && (tzoff == -1)) {
+        /* this just must be a time zone string */
+        tzoff = checktz(buf);
+        if(tzoff != -1)
+          found = TRUE;
+      }
+
+      if(!found)
+        return PARSEDATE_FAIL; /* bad string */
+
+      date += len;
+    }
+    else if(ISDIGIT(*date)) {
+      /* a digit */
+      int val;
+      char *end;
+      if((secnum == -1) &&
+         (3 == sscanf(date, "%02d:%02d:%02d", &hournum, &minnum, &secnum))) {
+        /* time stamp! */
+        date += 8;
+      }
+      else if((secnum == -1) &&
+              (2 == sscanf(date, "%02d:%02d", &hournum, &minnum))) {
+        /* time stamp without seconds */
+        date += 5;
+        secnum = 0;
+      }
+      else {
+        long lval;
+        int error;
+        int old_errno;
+
+        old_errno = ERRNO;
+        SET_ERRNO(0);
+        lval = strtol(date, &end, 10);
+        error = ERRNO;
+        if(error != old_errno)
+          SET_ERRNO(old_errno);
+
+        if(error)
+          return PARSEDATE_FAIL;
+
+#if LONG_MAX != INT_MAX
+        if((lval > (long)INT_MAX) || (lval < (long)INT_MIN))
+          return PARSEDATE_FAIL;
+#endif
+
+        val = clamp_to_int(lval);
+
+        if((tzoff == -1) &&
+           ((end - date) == 4) &&
+           (val <= 1400) &&
+           (indate< date) &&
+           ((date[-1] == '+' || date[-1] == '-'))) {
+          /* four digits and a value less than or equal to 1400 (to take into
+             account all sorts of funny time zone diffs) and it is preceded
+             with a plus or minus. This is a time zone indication.  1400 is
+             picked since +1300 is frequently used and +1400 is mentioned as
+             an edge number in the document "ISO C 200X Proposal: Timezone
+             Functions" at http://david.tribble.com/text/c0xtimezone.html If
+             anyone has a more authoritative source for the exact maximum time
+             zone offsets, please speak up! */
+          found = TRUE;
+          tzoff = (val/100 * 60 + val%100)*60;
+
+          /* the + and - prefix indicates the local time compared to GMT,
+             this we need ther reversed math to get what we want */
+          tzoff = date[-1]=='+'?-tzoff:tzoff;
+        }
+
+        if(((end - date) == 8) &&
+           (yearnum == -1) &&
+           (monnum == -1) &&
+           (mdaynum == -1)) {
+          /* 8 digits, no year, month or day yet. This is YYYYMMDD */
+          found = TRUE;
+          yearnum = val/10000;
+          monnum = (val%10000)/100-1; /* month is 0 - 11 */
+          mdaynum = val%100;
+        }
+
+        if(!found && (dignext == DATE_MDAY) && (mdaynum == -1)) {
+          if((val > 0) && (val<32)) {
+            mdaynum = val;
+            found = TRUE;
+          }
+          dignext = DATE_YEAR;
+        }
+
+        if(!found && (dignext == DATE_YEAR) && (yearnum == -1)) {
+          yearnum = val;
+          found = TRUE;
+          if(yearnum < 1900) {
+            if(yearnum > 70)
+              yearnum += 1900;
+            else
+              yearnum += 2000;
+          }
+          if(mdaynum == -1)
+            dignext = DATE_MDAY;
+        }
+
+        if(!found)
+          return PARSEDATE_FAIL;
+
+        date = end;
+      }
+    }
+
+    part++;
+  }
+
+  if(-1 == secnum)
+    secnum = minnum = hournum = 0; /* no time, make it zero */
+
+  if((-1 == mdaynum) ||
+     (-1 == monnum) ||
+     (-1 == yearnum))
+    /* lacks vital info, fail */
+    return PARSEDATE_FAIL;
+
+#if SIZEOF_TIME_T < 5
+  /* 32 bit time_t can only hold dates to the beginning of 2038 */
+  if(yearnum > 2037) {
+    *output = 0x7fffffff;
+    return PARSEDATE_LATER;
+  }
+#endif
+
+  if(yearnum < 1970) {
+    *output = 0;
+    return PARSEDATE_SOONER;
+  }
+
+  if((mdaynum > 31) || (monnum > 11) ||
+     (hournum > 23) || (minnum > 59) || (secnum > 60))
+    return PARSEDATE_FAIL; /* clearly an illegal date */
+
+  tm.tm_sec = secnum;
+  tm.tm_min = minnum;
+  tm.tm_hour = hournum;
+  tm.tm_mday = mdaynum;
+  tm.tm_mon = monnum;
+  tm.tm_year = yearnum - 1900;
+
+  /* my_timegm() returns a time_t. time_t is often 32 bits, even on many
+     architectures that feature 64 bit 'long'.
+
+     Some systems have 64 bit time_t and deal with years beyond 2038. However,
+     even on some of the systems with 64 bit time_t mktime() returns -1 for
+     dates beyond 03:14:07 UTC, January 19, 2038. (Such as AIX 5100-06)
+  */
+  t = my_timegm(&tm);
+
+  /* time zone adjust (cast t to int to compare to negative one) */
+  if(-1 != (int)t) {
+
+    /* Add the time zone diff between local time zone and GMT. */
+    long delta = (long)(tzoff!=-1?tzoff:0);
+
+    if((delta>0) && (t > LONG_MAX  - delta))
+      return -1; /* time_t overflow */
+
+    t += delta;
+  }
+
+  *output = t;
+
+  return PARSEDATE_OK;
+}
+
+time_t parse_date(const char *p)
+{
+  time_t parsed;
+  int rc = parsedate(p, &parsed);
+
+  switch(rc) {
+  case PARSEDATE_OK:
+  case PARSEDATE_LATER:
+  case PARSEDATE_SOONER:
+    return parsed;
+  }
+  /* everything else is fail */
+  return -1;
+}
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/src/util/raster.cpp b/src/util/raster.cpp
index 9a71573d01..7b52c51037 100644
--- a/src/util/raster.cpp
+++ b/src/util/raster.cpp
@@ -1,20 +1,19 @@
-#include <mbgl/util/raster.hpp>
-
-#include <memory>
-#include <cassert>
-#include <cstring>
-
 #include <mbgl/platform/platform.hpp>
 #include <mbgl/platform/gl.hpp>
+
+#include <mbgl/util/raster.hpp>
 #include <mbgl/util/time.hpp>
 #include <mbgl/util/uv_detail.hpp>
 #include <mbgl/util/std.hpp>
 
 #include <png.h>
 
+#include <cassert>
+#include <cstring>
+
 using namespace mbgl;
 
-Raster::Raster(const std::shared_ptr<Texturepool> &texturepool)
+Raster::Raster(const util::ptr<Texturepool> &texturepool)
     : texturepool(texturepool)
 {}
 
diff --git a/src/util/sqlite3.cpp b/src/util/sqlite3.cpp
new file mode 100644
index 0000000000..19e0ce9c79
--- /dev/null
+++ b/src/util/sqlite3.cpp
@@ -0,0 +1,166 @@
+#include <mbgl/util/sqlite3.hpp>
+#include <sqlite3.h>
+
+#include <cassert>
+
+namespace mapbox {
+namespace sqlite {
+
+Database::Database(const std::string &filename, int flags) {
+    const int err = sqlite3_open_v2(filename.c_str(), &db, flags, nullptr);
+    if (err != SQLITE_OK) {
+        Exception ex { err, sqlite3_errmsg(db) };
+        db = nullptr;
+        throw ex;
+    }
+}
+
+Database::Database(Database &&other) {
+    *this = std::move(other);
+}
+
+Database &Database::operator=(Database &&other) {
+    std::swap(db, other.db);
+    return *this;
+}
+
+Database::~Database() {
+    if (db) {
+        const int err = sqlite3_close(db);
+        if (err != SQLITE_OK) {
+            throw Exception { err, sqlite3_errmsg(db) };
+        }
+    }
+}
+
+Database::operator bool() const {
+    return db != nullptr;
+}
+
+void Database::exec(const std::string &sql) {
+    assert(db);
+    char *msg = nullptr;
+    const int err = sqlite3_exec(db, sql.c_str(), nullptr, nullptr, &msg);
+    if (msg) {
+        Exception ex { err, msg };
+        sqlite3_free(msg);
+        throw ex;
+    } else if (err != SQLITE_OK) {
+        throw Exception { err, sqlite3_errmsg(db) };
+    }
+}
+
+Statement Database::prepare(const char *query) {
+    assert(db);
+    return std::move(Statement(db, query));
+}
+
+Statement::Statement(sqlite3 *db, const char *sql) {
+    const int err = sqlite3_prepare_v2(db, sql, -1, &stmt, nullptr);
+    if (err != SQLITE_OK) {
+        stmt = nullptr;
+        throw Exception { err, sqlite3_errmsg(db) };
+    }
+}
+
+#define CHECK_SQLITE_OK(err) \
+    if (err != SQLITE_OK) { \
+        throw Exception { err, sqlite3_errmsg(sqlite3_db_handle(stmt)) }; \
+    }
+
+Statement::Statement(Statement &&other) {
+    *this = std::move(other);
+}
+
+Statement &Statement::operator=(Statement &&other) {
+    std::swap(stmt, other.stmt);
+    return *this;
+}
+
+Statement::~Statement() {
+    if (stmt) {
+        const int err = sqlite3_finalize(stmt);
+        CHECK_SQLITE_OK(err)
+    }
+}
+
+Statement::operator bool() const {
+    return stmt != nullptr;
+}
+
+#define BIND_3(type, value) \
+    assert(stmt); \
+    const int err = sqlite3_bind_##type(stmt, offset, value); \
+    CHECK_SQLITE_OK(err)
+
+#define BIND_5(type, value, length, param) \
+    assert(stmt); \
+    const int err = sqlite3_bind_##type(stmt, offset, value, length, param); \
+    CHECK_SQLITE_OK(err)
+
+template <> void Statement::bind(int offset, int value) {
+    BIND_3(int, value)
+}
+
+template <> void Statement::bind(int offset, int64_t value) {
+    BIND_3(int64, value)
+}
+
+template <> void Statement::bind(int offset, double value) {
+    BIND_3(double, value)
+}
+
+template <> void Statement::bind(int offset, bool value) {
+    BIND_3(int, value)
+}
+
+template <> void Statement::bind(int offset, const char *value) {
+    BIND_5(text, value, -1, nullptr)
+}
+
+void Statement::bind(int offset, const std::string &value, bool retain) {
+    BIND_5(blob, value.data(), int(value.size()), retain ? SQLITE_TRANSIENT : SQLITE_STATIC)
+}
+
+bool Statement::run() {
+    assert(stmt);
+    const int err = sqlite3_step(stmt);
+    if (err == SQLITE_DONE) {
+        return false;
+    } else if (err == SQLITE_ROW) {
+        return true;
+    } else {
+        throw std::runtime_error("failed to run statement");
+    }
+}
+
+template <> int Statement::get(int offset) {
+    assert(stmt);
+    return sqlite3_column_int(stmt, offset);
+}
+
+template <> int64_t Statement::get(int offset) {
+    assert(stmt);
+    return sqlite3_column_int64(stmt, offset);
+}
+
+template <> double Statement::get(int offset) {
+    assert(stmt);
+    return sqlite3_column_double(stmt, offset);
+}
+
+template <> std::string Statement::get(int offset) {
+    assert(stmt);
+    return {
+        reinterpret_cast<const char *>(sqlite3_column_blob(stmt, offset)),
+        size_t(sqlite3_column_bytes(stmt, offset))
+    };
+}
+
+void Statement::reset() {
+    assert(stmt);
+    sqlite3_reset(stmt);
+}
+
+}
+}
diff --git a/src/util/uv-channel.c b/src/util/uv-channel.c
new file mode 100644
index 0000000000..4e3b9fa5ff
--- /dev/null
+++ b/src/util/uv-channel.c
@@ -0,0 +1,69 @@
+#include <mbgl/util/uv-channel.h>
+#include <mbgl/util/queue.h>
+
+#include <stdlib.h>
+
+// Taken from http://navaneeth.github.io/blog/2013/08/02/channels-in-libuv/
+
+typedef struct {
+    void *data;
+    void *active_queue[2];
+} uv__chan_item_t;
+
+int uv_chan_init(uv_chan_t *chan) {
+    int r = uv_mutex_init(&chan->mutex);
+    if (r == -1)
+        return r;
+
+    QUEUE_INIT(&chan->q);
+
+    return uv_cond_init(&chan->cond);
+}
+
+void uv_chan_send(uv_chan_t *chan, void *data) {
+    uv__chan_item_t *item = (uv__chan_item_t *)malloc(sizeof(uv__chan_item_t));
+    item->data = data;
+
+    uv_mutex_lock(&chan->mutex);
+    QUEUE_INSERT_TAIL(&chan->q, &item->active_queue);
+    uv_cond_signal(&chan->cond);
+    uv_mutex_unlock(&chan->mutex);
+}
+
+void *uv_chan_receive(uv_chan_t *chan) {
+    uv__chan_item_t *item;
+    QUEUE *head;
+    void *data = NULL;
+
+    uv_mutex_lock(&chan->mutex);
+    while (QUEUE_EMPTY(&chan->q)) {
+        uv_cond_wait(&chan->cond, &chan->mutex);
+    }
+
+    head = QUEUE_HEAD(&chan->q);
+    item = QUEUE_DATA(head, uv__chan_item_t, active_queue);
+    data = item->data;
+    QUEUE_REMOVE(head);
+    free(item);
+    uv_mutex_unlock(&chan->mutex);
+    return data;
+}
+
+void uv_chan_clear(uv_chan_t *chan) {
+    uv_mutex_lock(&chan->mutex);
+    uv__chan_item_t *item = NULL;
+    QUEUE *head = NULL;
+    while (!QUEUE_EMPTY(&chan->q)) {
+        head = QUEUE_HEAD(&chan->q);
+        item = QUEUE_DATA(head, uv__chan_item_t, active_queue);
+        QUEUE_REMOVE(head);
+        free(item);
+    }
+    uv_mutex_unlock(&chan->mutex);
+}
+
+void uv_chan_destroy(uv_chan_t *chan) {
+    uv_chan_clear(chan);
+    uv_cond_destroy(&chan->cond);
+    uv_mutex_destroy(&chan->mutex);
+}
diff --git a/src/util/uv-messenger.c b/src/util/uv-messenger.c
new file mode 100644
index 0000000000..a25c84dc59
--- /dev/null
+++ b/src/util/uv-messenger.c
@@ -0,0 +1,74 @@
+#include <mbgl/util/uv-messenger.h>
+#include <mbgl/util/queue.h>
+
+#include <stdlib.h>
+
+typedef struct {
+    void *data;
+    void *queue[2];
+} uv__messenger_item_t;
+
+void uv__messenger_callback(uv_async_t *async) {
+    uv_messenger_t *msgr = (uv_messenger_t *)async->data;
+
+    uv__messenger_item_t *item;
+    QUEUE *head;
+
+    while (1) {
+        uv_mutex_lock(&msgr->mutex);
+        if (QUEUE_EMPTY(&msgr->queue)) {
+            uv_mutex_unlock(&msgr->mutex);
+            break;
+        }
+
+        head = QUEUE_HEAD(&msgr->queue);
+        item = QUEUE_DATA(head, uv__messenger_item_t, queue);
+        QUEUE_REMOVE(head);
+        uv_mutex_unlock(&msgr->mutex);
+
+        msgr->callback(item->data);
+
+        free(item);
+    }
+}
+
+int uv_messenger_init(uv_loop_t *loop, uv_messenger_t *msgr, uv_messenger_cb callback) {
+    int ret = uv_mutex_init(&msgr->mutex);
+    if (ret < 0) {
+        return ret;
+    }
+
+    msgr->callback = callback;
+
+    QUEUE_INIT(&msgr->queue);
+
+    msgr->async.data = msgr;
+    return uv_async_init(loop, &msgr->async, uv__messenger_callback);
+}
+
+void uv_messenger_send(uv_messenger_t *msgr, void *data) {
+    uv__messenger_item_t *item = (uv__messenger_item_t *)malloc(sizeof(uv__messenger_item_t));
+    item->data = data;
+
+    uv_mutex_lock(&msgr->mutex);
+    QUEUE_INSERT_TAIL(&msgr->queue, &item->queue);
+    uv_mutex_unlock(&msgr->mutex);
+
+    uv_async_send(&msgr->async);
+}
+
+void uv_messenger_ref(uv_messenger_t *msgr) {
+    uv_ref((uv_handle_t *)&msgr->async);
+}
+
+void uv_messenger_unref(uv_messenger_t *msgr) {
+    uv_unref((uv_handle_t *)&msgr->async);
+}
+
+void uv__messenger_stop_callback(uv_handle_t *handle) {
+    free((uv_messenger_t *)handle->data);
+}
+
+void uv_messenger_stop(uv_messenger_t *msgr) {
+    uv_close((uv_handle_t *)&msgr->async, uv__messenger_stop_callback);
+}
diff --git a/src/util/uv-worker.c b/src/util/uv-worker.c
new file mode 100644
index 0000000000..8b0cc6dda7
--- /dev/null
+++ b/src/util/uv-worker.c
@@ -0,0 +1,166 @@
+#include <mbgl/util/uv-worker.h>
+#include <mbgl/util/uv-messenger.h>
+
+#include <stdio.h>
+#include <assert.h>
+
+typedef struct uv__worker_item_s uv__worker_item_t;
+struct uv__worker_item_s {
+    uv_worker_t *worker;
+    void *data;
+    uv_worker_cb work_cb;
+    uv_worker_after_cb after_work_cb;
+};
+
+typedef struct uv__worker_thread_s uv__worker_thread_t;
+struct uv__worker_thread_s {
+    uv_worker_t *worker;
+    uv_thread_t thread;
+};
+
+void uv__worker_thread_finished(uv__worker_thread_t *worker_thread) {
+    uv_worker_t *worker = worker_thread->worker;
+
+#ifndef NDEBUG
+    assert(uv_thread_self() == worker->thread_id);
+#endif
+
+    // This should at most block very briefly. We are sending the termination
+    // notification as the last thing in the worker thread, so by now the thread
+    // has probably terminated already. If not, the waiting time should be
+    // extremely short.
+    uv_thread_join(&worker_thread->thread);
+
+    assert(worker->count > 0);
+    worker->count--;
+    if (worker->count == 0) {
+        uv_chan_destroy(&worker->chan);
+        uv_messenger_stop(worker->msgr);
+        if (worker->close_cb) {
+            worker->close_cb(worker);
+        }
+    }
+}
+
+void uv__worker_after(void *ptr) {
+    uv__worker_item_t *item = (uv__worker_item_t *)ptr;
+
+    if (item->work_cb) {
+        // We are finishing a regular work request.
+        if (item->after_work_cb) {
+            assert(item->after_work_cb);
+            item->after_work_cb(item->data);
+        }
+        uv_worker_t *worker = item->worker;
+        assert(worker->active_items > 0);
+        if (--worker->active_items == 0) {
+            uv_messenger_unref(worker->msgr);
+        }
+    } else {
+        // This is a worker thread termination.
+        uv__worker_thread_t *worker_thread = (uv__worker_thread_t *)item->data;
+        uv__worker_thread_finished(worker_thread);
+        free(worker_thread);
+    }
+
+    free(item);
+}
+
+void uv__worker_thread_loop(void *ptr) {
+    uv__worker_thread_t *worker_thread = (uv__worker_thread_t *)ptr;
+    uv_worker_t *worker = worker_thread->worker;
+
+#ifdef __APPLE__
+    if (worker->name) {
+        pthread_setname_np(worker->name);
+    }
+#endif
+
+    uv__worker_item_t *item = NULL;
+    while ((item = (uv__worker_item_t *)uv_chan_receive(&worker->chan)) != NULL) {
+        assert(item->work_cb);
+        item->work_cb(item->data);
+
+        // Trigger the after callback in the main thread.
+        uv_messenger_send(worker->msgr, item);
+    }
+
+    // Make sure to close all other workers too.
+    uv_chan_send(&worker->chan, NULL);
+
+    // Create a new worker item that acts as a terminate flag for this thread.
+    item = (uv__worker_item_t *)malloc(sizeof(uv__worker_item_t));
+    item->data = worker_thread;
+    item->work_cb = NULL;
+    item->after_work_cb = NULL;
+    uv_messenger_send(worker->msgr, item);
+}
+
+int uv_worker_init(uv_worker_t *worker, uv_loop_t *loop, int count, const char *name) {
+#ifndef NDEBUG
+    worker->thread_id = uv_thread_self();
+#endif
+    worker->loop = loop;
+    worker->name = name;
+    worker->count = 0;
+    worker->close_cb = NULL;
+    worker->active_items = 0;
+    worker->msgr = (uv_messenger_t *)malloc(sizeof(uv_messenger_t));
+    int ret = uv_messenger_init(loop, worker->msgr, uv__worker_after);
+    if (ret < 0) {
+        free(worker->msgr);
+        return ret;
+    }
+    uv_messenger_unref(worker->msgr);
+    ret = uv_chan_init(&worker->chan);
+    if (ret < 0) return ret;
+
+    // Initialize all worker threads.
+    int i;
+    for (i = 0; i < count; i++) {
+        uv__worker_thread_t *worker_thread = (uv__worker_thread_t *)malloc(sizeof(uv__worker_thread_t));
+        worker_thread->worker = worker;
+        ret = uv_thread_create(&worker_thread->thread, uv__worker_thread_loop, worker_thread);
+        if (ret < 0) return ret;
+        worker->count++;
+    }
+
+    return 0;
+}
+
+void uv_worker_send(uv_worker_t *worker, void *data, uv_worker_cb work_cb,
+                    uv_worker_after_cb after_work_cb) {
+#ifndef NDEBUG
+    assert(uv_thread_self() == worker->thread_id);
+#endif
+
+    // It doesn't make sense to not provide a work callback. On the other hand, the after_work_cb
+    // may be NULL. In that case, there will be no callback called in the current thread and the
+    // worker item will instead be freed in the worker thread.
+    assert(work_cb);
+
+    uv__worker_item_t *item = (uv__worker_item_t *)malloc(sizeof(uv__worker_item_t));
+    item->worker = worker;
+    item->work_cb = work_cb;
+    item->after_work_cb = after_work_cb;
+    item->data = data;
+    uv_chan_send(&worker->chan, item);
+    if (worker->active_items++ == 0) {
+        uv_messenger_ref(worker->msgr);
+    }
+}
+
+void uv_worker_close(uv_worker_t *worker, uv_worker_close_cb close_cb) {
+#ifndef NDEBUG
+    assert(uv_thread_self() == worker->thread_id);
+#endif
+
+    // Prevent double calling.
+    assert(worker->close_cb == NULL);
+
+    worker->close_cb = close_cb;
+    uv_chan_send(&worker->chan, NULL);
+    if (worker->active_items++ == 0) {
+        uv_messenger_ref(worker->msgr);
+    }
+}
diff --git a/src/util/uv.cpp b/src/util/uv.cpp
index 94f074bfa1..6e15ac4537 100644
--- a/src/util/uv.cpp
+++ b/src/util/uv.cpp
@@ -16,4 +16,16 @@ std::string cwd() {
     return dir;
 }
 
+void deleter::operator()(uv_async_t *async) {
+    uv_close((uv_handle_t *)async, [](uv_handle_t *handle) {
+        delete (uv_async_t *)handle;
+    });
+}
+
+void deleter::operator()(uv_timer_t *timer) {
+    uv_close((uv_handle_t *)timer, [](uv_handle_t *handle) {
+        delete (uv_timer_t *)handle;
+    });
+}
+
 }