[core] Refactor TileJSON parsing for offline

3 files changed, 49 insertions, 22 deletions

diff --git a/src/mbgl/map/source.cpp b/src/mbgl/map/source.cpp
index 65b9de7abb..b142a8471f 100644
--- a/src/mbgl/map/source.cpp
+++ b/src/mbgl/map/source.cpp
@@ -13,7 +13,6 @@
 #include <mbgl/util/math.hpp>
 #include <mbgl/util/box.hpp>
 #include <mbgl/util/tile_coordinate.hpp>
-#include <mbgl/util/mapbox.hpp>
 #include <mbgl/storage/file_source.hpp>
 #include <mbgl/style/style_layer.hpp>
 #include <mbgl/style/style_update_parameters.hpp>
@@ -22,7 +21,6 @@
 #include <mbgl/util/token.hpp>
 #include <mbgl/util/string.hpp>
 #include <mbgl/util/tile_cover.hpp>
-#include <mbgl/util/url.hpp>
 
 #include <mbgl/map/vector_tile_data.hpp>
 #include <mbgl/map/raster_tile_data.hpp>
@@ -102,29 +100,19 @@ void Source::load() {
             return;
         }
 
-        rapidjson::GenericDocument<rapidjson::UTF8<>, rapidjson::CrtAllocator> d;
-        d.Parse<0>(res.data->c_str());
-
-        if (d.HasParseError()) {
-            std::stringstream message;
-            message << d.GetErrorOffset() << " - " << rapidjson::GetParseError_En(d.GetParseError());
-            observer->onSourceError(*this, std::make_exception_ptr(std::runtime_error(message.str())));
-            return;
-        }
-
         bool reloadTiles = false;
+
         if (type == SourceType::Vector || type == SourceType::Raster) {
+            std::unique_ptr<SourceInfo> newInfo;
+
             // Create a new copy of the SourceInfo object that holds the base values we've parsed
             // from the stylesheet. Then merge in the values parsed from the TileJSON we retrieved
             // via the URL.
-            auto newInfo = StyleParser::parseTileJSON(d);
-
-            // TODO: Remove this hack by delivering proper URLs in the TileJSON to begin with.
-            if (type == SourceType::Raster && util::mapbox::isMapboxURL(url)) {
-                // We need to insert {ratio} into raster source URLs that are loaded from mapbox://
-                // TileJSONs.
-                std::transform(newInfo->tiles.begin(), newInfo->tiles.end(), newInfo->tiles.begin(),
-                               util::mapbox::normalizeRasterTileURL);
+            try {
+                newInfo = StyleParser::parseTileJSON(*res.data, url);
+            } catch (...) {
+                observer->onSourceError(*this, std::current_exception());
+                return;
             }
 
             // Check whether previous information specifies different tile
@@ -149,6 +137,17 @@ void Source::load() {
             info = std::move(newInfo);
         } else if (type == SourceType::GeoJSON) {
             info = std::make_unique<SourceInfo>();
+
+            rapidjson::GenericDocument<rapidjson::UTF8<>, rapidjson::CrtAllocator> d;
+            d.Parse<0>(res.data->c_str());
+
+            if (d.HasParseError()) {
+                std::stringstream message;
+                message << d.GetErrorOffset() << " - " << rapidjson::GetParseError_En(d.GetParseError());
+                observer->onSourceError(*this, std::make_exception_ptr(std::runtime_error(message.str())));
+                return;
+            }
+
             geojsonvt = StyleParser::parseGeoJSON(d);
             reloadTiles = true;
         }
diff --git a/src/mbgl/style/style_parser.cpp b/src/mbgl/style/style_parser.cpp
index aca4e647d2..1b088bd38f 100644
--- a/src/mbgl/style/style_parser.cpp
+++ b/src/mbgl/style/style_parser.cpp
@@ -11,10 +11,13 @@
 #include <mapbox/geojsonvt.hpp>
 #include <mapbox/geojsonvt/convert.hpp>
 
+#include <mbgl/util/mapbox.hpp>
+
 #include <rapidjson/document.h>
 #include <rapidjson/error/en.h>
 
 #include <algorithm>
+#include <sstream>
 
 namespace mbgl {
 
@@ -101,7 +104,7 @@ StyleParser::~StyleParser() = default;
 
 void StyleParser::parse(const std::string& json) {
     rapidjson::GenericDocument<rapidjson::UTF8<>, rapidjson::CrtAllocator> document;
-    document.Parse<0>((const char *const)json.c_str());
+    document.Parse<0>(json.c_str());
 
     if (document.HasParseError()) {
         Log::Error(Event::ParseStyle, "Error parsing style JSON at %i: %s", document.GetErrorOffset(), rapidjson::GetParseError_En(document.GetParseError()));
@@ -252,6 +255,29 @@ std::unique_ptr<mapbox::geojsonvt::GeoJSONVT> StyleParser::parseGeoJSON(const JS
     }
 }
 
+std::unique_ptr<SourceInfo> StyleParser::parseTileJSON(const std::string& json, const std::string& sourceURL) {
+    rapidjson::GenericDocument<rapidjson::UTF8<>, rapidjson::CrtAllocator> document;
+    document.Parse<0>(json.c_str());
+
+    if (document.HasParseError()) {
+        std::stringstream message;
+        message << document.GetErrorOffset() << " - " << rapidjson::GetParseError_En(document.GetParseError());
+        throw std::runtime_error(message.str());
+    }
+
+    std::unique_ptr<SourceInfo> result = StyleParser::parseTileJSON(document);
+
+    // TODO: Remove this hack by delivering proper URLs in the TileJSON to begin with.
+    if (util::mapbox::isMapboxURL(sourceURL)) {
+        std::transform(result->tiles.begin(),
+                       result->tiles.end(),
+                       result->tiles.begin(),
+                       util::mapbox::normalizeRasterTileURL);
+    }
+
+    return result;
+}
+
 std::unique_ptr<SourceInfo> StyleParser::parseTileJSON(const JSValue& value) {
     auto info = std::make_unique<SourceInfo>();
     parseTileJSONMember(value, info->tiles, "tiles");
diff --git a/src/mbgl/style/style_parser.hpp b/src/mbgl/style/style_parser.hpp
index 58c4d736f2..3a0d0fb6b4 100644
--- a/src/mbgl/style/style_parser.hpp
+++ b/src/mbgl/style/style_parser.hpp
@@ -28,9 +28,11 @@ public:
     std::vector<std::unique_ptr<Source>> sources;
     std::vector<std::unique_ptr<StyleLayer>> layers;
 
-    static std::unique_ptr<mapbox::geojsonvt::GeoJSONVT> parseGeoJSON(const JSValue&);
+    static std::unique_ptr<SourceInfo> parseTileJSON(const std::string& json, const std::string& sourceURL);
     static std::unique_ptr<SourceInfo> parseTileJSON(const JSValue&);
 
+    static std::unique_ptr<mapbox::geojsonvt::GeoJSONVT> parseGeoJSON(const JSValue&);
+
 private:
     void parseSources(const JSValue&);
     void parseLayers(const JSValue&);