Enable HTTP loading in Mojo dart content handler

tonic/dart_library_provider_network.cc

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "tonic/dart_library_provider_network.h"
+
+#include "base/bind.h"
+#include "base/strings/string_util.h"
+#include "tonic/dart_converter.h"
+#include "url/gurl.h"
+
+namespace tonic {
+namespace {
+
+mojo::URLLoaderPtr Fetch(mojo::NetworkService* network_service,
+                         const std::string& url,
+                         base::Callback<void(mojo::URLResponsePtr)> callback) {
+  mojo::URLLoaderPtr loader;
+  network_service->CreateURLLoader(GetProxy(&loader));
+
+  mojo::URLRequestPtr request = mojo::URLRequest::New();
+  request->url = url;
+  request->auto_follow_redirects = true;
+  loader->Start(request.Pass(), callback);
+
+  return loader.Pass();
+}
+
+// Helper to erase a T* from a container of std::unique_ptr<T>s.
+template<typename T, typename C>
+void EraseUniquePtr(C& container, T* item) {
+  std::unique_ptr<T> key = std::unique_ptr<T>(item);
+  container.erase(key);
+  key.release();
+}
+
+}  // namespace
+
+class DartLibraryProviderNetwork::Job {
+ public:
+  Job(DartLibraryProviderNetwork* provider,
+      const std::string& name,
+      DataPipeConsumerCallback callback)
+      : provider_(provider), callback_(callback), weak_factory_(this) {
+    url_loader_ =
+        Fetch(provider_->network_service(), name,
+              base::Bind(&Job::OnReceivedResponse, weak_factory_.GetWeakPtr()));
+  }
+
+ private:
+  void OnReceivedResponse(mojo::URLResponsePtr response) {
+    mojo::ScopedDataPipeConsumerHandle data;
+    if (response->status_code == 200)
+      data = response->body.Pass();
+    callback_.Run(data.Pass());
+    EraseUniquePtr(provider_->jobs_, this);
+    // We're deleted now.
+  }
+
+  DartLibraryProviderNetwork* provider_;
+  DataPipeConsumerCallback callback_;
+  mojo::URLLoaderPtr url_loader_;
+
+  base::WeakPtrFactory<Job> weak_factory_;
+};
+
+DartLibraryProviderNetwork::DartLibraryProviderNetwork(
+    mojo::NetworkService* network_service)
+    : network_service_(network_service) {
+}
+
+DartLibraryProviderNetwork::~DartLibraryProviderNetwork() {
+}
+
+void DartLibraryProviderNetwork::GetLibraryAsStream(
+    const std::string& name,
+    DataPipeConsumerCallback callback) {
+  jobs_.insert(std::unique_ptr<Job>(new Job(this, name, callback)));
+}
+
+Dart_Handle DartLibraryProviderNetwork::CanonicalizeURL(Dart_Handle library,
+                                                        Dart_Handle url) {
+  std::string string = StdStringFromDart(url);
+  if (StartsWithASCII(string, "dart:", true))
+    return url;
+  // TODO(abarth): The package root should be configurable.
+  if (StartsWithASCII(string, "package:", true))
+    ReplaceFirstSubstringAfterOffset(&string, 0, "package:", "/packages/");
+  GURL library_url(StdStringFromDart(Dart_LibraryUrl(library)));
+  GURL resolved_url = library_url.Resolve(string);
+  return StdStringToDart(resolved_url.spec());
+}
+
+}  // namespace tonic