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#include <mbgl/storage/default_file_source_impl.hpp>
#include <mbgl/storage/request.hpp>
#include <mbgl/storage/asset_request.hpp>
#include <mbgl/storage/http_request.hpp>
#include <mbgl/storage/response.hpp>
#include <mbgl/platform/platform.hpp>
#include <mbgl/util/uv_detail.hpp>
#include <mbgl/util/chrono.hpp>
#include <mbgl/util/thread.hpp>
#include <mbgl/platform/log.hpp>
#include <mbgl/map/environment.hpp>
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wshadow"
#ifndef __clang__
#pragma GCC diagnostic ignored "-Wunused-local-typedefs"
#endif
#include <boost/algorithm/string.hpp>
#pragma GCC diagnostic pop
#include <algorithm>
#include <cassert>
namespace algo = boost::algorithm;
namespace mbgl {
DefaultFileSource::Impl::Impl(FileCache* cache_, const std::string& root)
: assetRoot(root.empty() ? platform::assetRoot() : root), cache(cache_) {
}
DefaultFileSource::DefaultFileSource(FileCache* cache, const std::string& root)
: thread(util::make_unique<util::Thread<Impl>>("FileSource", cache, root)) {
}
DefaultFileSource::~DefaultFileSource() {
MBGL_VERIFY_THREAD(tid);
}
SharedRequestBase *DefaultFileSource::Impl::find(const Resource &resource) {
// We're using a set of pointers here instead of a map between url and SharedRequestBase because
// we need to find the requests both by pointer and by URL. Given that the number of requests
// is generally very small (typically < 10 at a time), hashing by URL incurs too much overhead
// anyway.
const auto it = pending.find(resource);
if (it != pending.end()) {
return it->second;
}
return nullptr;
}
Request* DefaultFileSource::request(const Resource& resource,
uv_loop_t* l,
const Environment& env,
Callback callback) {
auto req = new Request(resource, l, env, std::move(callback));
// This function can be called from any thread. Make sure we're executing the actual call in the
// file source loop by sending it over the queue.
thread->invoke(&Impl::add, std::move(req), thread->get());
return req;
}
void DefaultFileSource::request(const Resource& resource, const Environment& env, Callback callback) {
request(resource, nullptr, env, std::move(callback));
}
void DefaultFileSource::cancel(Request *req) {
req->cancel();
// This function can be called from any thread. Make sure we're executing the actual call in the
// file source loop by sending it over the queue.
thread->invoke(&Impl::cancel, std::move(req));
}
void DefaultFileSource::abort(const Environment &env) {
thread->invoke(&Impl::abort, std::ref(env));
}
void DefaultFileSource::Impl::add(Request* req, uv_loop_t* loop) {
const Resource &resource = req->resource;
// We're adding a new Request.
SharedRequestBase *sharedRequest = find(resource);
if (!sharedRequest) {
// There is no request for this URL yet. Create a new one and start it.
if (algo::starts_with(resource.url, "asset://")) {
sharedRequest = new AssetRequest(this, resource);
} else {
sharedRequest = new HTTPRequest(this, resource);
}
const bool inserted = pending.emplace(resource, sharedRequest).second;
assert(inserted);
(void (inserted)); // silence unused variable warning on Release builds.
// But first, we're going to start querying the database if it exists.
if (!cache) {
sharedRequest->start(loop);
} else {
// Otherwise, first check the cache for existing data so that we can potentially
// revalidate the information without having to redownload everything.
cache->get(resource, [this, resource, loop](std::unique_ptr<Response> response) {
processResult(resource, std::move(response), loop);
});
}
}
sharedRequest->subscribe(req);
}
void DefaultFileSource::Impl::cancel(Request* req) {
SharedRequestBase *sharedRequest = find(req->resource);
if (sharedRequest) {
// If the number of dependent requests of the SharedRequestBase drops to zero, the
// unsubscribe callback triggers the removal of the SharedRequestBase pointer from the list
// of pending requests and initiates cancelation.
sharedRequest->unsubscribe(req);
} else {
// There is no request for this URL anymore. Likely, the request already completed
// before we got around to process the cancelation request.
}
// Send a message back to the requesting thread and notify it that this request has been
// canceled and is now safe to be deleted.
req->destruct();
}
void DefaultFileSource::Impl::processResult(const Resource& resource, std::shared_ptr<const Response> response, uv_loop_t* loop) {
SharedRequestBase *sharedRequest = find(resource);
if (sharedRequest) {
if (response) {
// 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>(
SystemClock::now().time_since_epoch()).count();
if (response->expires > now) {
// The response is fresh. We're good to notify the caller.
sharedRequest->notify(response, FileCache::Hint::No);
sharedRequest->cancel();
return;
} else {
// The cached response is stale. Now run the real request.
sharedRequest->start(loop, response);
}
} else {
// There is no response. Now run the real request.
sharedRequest->start(loop);
}
} else {
// There is no request for this URL anymore. Likely, the request was canceled
// before we got around to process the cache result.
}
}
// Aborts all requests that are part of the current environment.
void DefaultFileSource::Impl::abort(const Environment& env) {
// Construct a cancellation response.
auto res = util::make_unique<Response>();
res->status = Response::Error;
res->message = "Environment is terminating";
std::shared_ptr<const Response> response = std::move(res);
// Iterate through all pending requests and remove them in case they're abandoned.
util::erase_if(pending, [&](const std::pair<Resource, SharedRequestBase *> &it) -> bool {
// Obtain all pending requests that are in the current environment.
const auto aborted = it.second->removeAllInEnvironment(env);
// Notify all observers.
for (auto req : aborted) {
req->notify(response);
}
// Finally, remove all requests that are now abandoned.
if (it.second->abandoned()) {
it.second->cancel();
return true;
} else {
return false;
}
});
}
void DefaultFileSource::Impl::notify(SharedRequestBase *sharedRequest,
const std::set<Request *> &observers,
std::shared_ptr<const Response> response, FileCache::Hint hint) {
// First, remove the request, since it might be destructed at any point now.
assert(find(sharedRequest->resource) == sharedRequest);
pending.erase(sharedRequest->resource);
if (response) {
if (cache) {
// Store response in database
cache->put(sharedRequest->resource, response, hint);
}
// Notify all observers.
for (auto req : observers) {
req->notify(response);
}
}
}
}
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