Wholesale move sky/engine/tonic to tonic

tonic/dart_library_loader.cc

Index: tonic/dart_library_loader.cc
diff --git a/tonic/dart_library_loader.cc b/tonic/dart_library_loader.cc
new file mode 100644
index 0000000000000000000000000000000000000000..a6492ad8835ba97c85850bc94b0d58c6e51a0924
--- /dev/null
+++ b/tonic/dart_library_loader.cc
@@ -0,0 +1,305 @@
+// 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_loader.h"
+
+#include "base/callback.h"
+#include "base/trace_event/trace_event.h"
+#include "mojo/common/data_pipe_drainer.h"
+#include "tonic/dart_api_scope.h"
+#include "tonic/dart_converter.h"
+#include "tonic/dart_dependency_catcher.h"
+#include "tonic/dart_error.h"
+#include "tonic/dart_isolate_scope.h"
+#include "tonic/dart_library_provider.h"
+#include "tonic/dart_state.h"
+
+using mojo::common::DataPipeDrainer;
+
+namespace blink {
+
+namespace {
+
+// 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();
+}
+
+}
+
+// A DartLibraryLoader::Job represents a network load. It fetches data from the
+// network and buffers the data in std::vector. To cancel the job, delete this
+// object.
+class DartLibraryLoader::Job : public DartDependency,
+                               public DataPipeDrainer::Client {
+ public:
+  Job(DartLibraryLoader* loader, const std::string& name)
+      : loader_(loader), name_(name), weak_factory_(this) {
+    loader->library_provider()->GetLibraryAsStream(
+        name, base::Bind(&Job::OnStreamAvailable, weak_factory_.GetWeakPtr()));
+  }
+
+  const std::string& name() const { return name_; }
+
+ protected:
+  DartLibraryLoader* loader_;
+  // TODO(abarth): Should we be using SharedBuffer to buffer the data?
+  std::vector<uint8_t> buffer_;
+
+ private:
+  void OnStreamAvailable(mojo::ScopedDataPipeConsumerHandle pipe) {
+    if (!pipe.is_valid()) {
+      loader_->DidFailJob(this);
+      return;
+    }
+    drainer_ = adoptPtr(new DataPipeDrainer(this, pipe.Pass()));
+  }
+
+  // DataPipeDrainer::Client
+  void OnDataAvailable(const void* data, size_t num_bytes) override {
+    const uint8_t* bytes = static_cast<const uint8_t*>(data);
+    buffer_.insert(buffer_.end(), bytes, bytes + num_bytes);
+  }
+  // Subclasses must implement OnDataComplete.
+
+  std::string name_;
+  OwnPtr<DataPipeDrainer> drainer_;
+
+  base::WeakPtrFactory<Job> weak_factory_;
+};
+
+class DartLibraryLoader::ImportJob : public Job {
+ public:
+  ImportJob(DartLibraryLoader* loader, const std::string& name) : Job(loader, name) {
+    TRACE_EVENT_ASYNC_BEGIN1("sky", "DartLibraryLoader::ImportJob", this, "url",
+                             name);
+  }
+
+ private:
+  // DataPipeDrainer::Client
+  void OnDataComplete() override {
+    TRACE_EVENT_ASYNC_END0("sky", "DartLibraryLoader::ImportJob", this);
+    loader_->DidCompleteImportJob(this, buffer_);
+  }
+};
+
+class DartLibraryLoader::SourceJob : public Job {
+ public:
+  SourceJob(DartLibraryLoader* loader, const std::string& name, Dart_Handle library)
+      : Job(loader, name), library_(loader->dart_state(), library) {
+    TRACE_EVENT_ASYNC_BEGIN1("sky", "DartLibraryLoader::SourceJob", this, "url",
+                             name);
+  }
+
+  Dart_PersistentHandle library() const { return library_.value(); }
+
+ private:
+  // DataPipeDrainer::Client
+  void OnDataComplete() override {
+    TRACE_EVENT_ASYNC_END0("sky", "DartLibraryLoader::SourceJob", this);
+    loader_->DidCompleteSourceJob(this, buffer_);
+  }
+
+  DartPersistentValue library_;
+};
+
+// A DependencyWatcher represents a request to watch for when a given set of
+// dependencies (either libraries or parts of libraries) have finished loading.
+// When the dependencies are satisfied (including transitive dependencies), then
+// the |callback| will be invoked.
+class DartLibraryLoader::DependencyWatcher {
+ public:
+  DependencyWatcher(const std::unordered_set<DartDependency*>& dependencies,
+                    const base::Closure& callback)
+      : dependencies_(dependencies), callback_(callback) {
+    DCHECK(!dependencies_.empty());
+  }
+
+  bool DidResolveDependency(
+      DartDependency* resolved_dependency,
+      const std::unordered_set<DartDependency*>& new_dependencies) {
+    const auto& it = dependencies_.find(resolved_dependency);
+    if (it == dependencies_.end())
+      return false;
+    dependencies_.erase(it);
+    for (const auto& dependency : new_dependencies)
+      dependencies_.insert(dependency);
+    return dependencies_.empty();
+  }
+
+  const base::Closure& callback() const { return callback_; }
+
+ private:
+  std::unordered_set<DartDependency*> dependencies_;
+  base::Closure callback_;
+};
+
+// A WatcherSignaler is responsible for signaling DependencyWatchers when their
+// dependencies resolve and for calling the DependencyWatcher's callback. We use
+// a separate object of this task because we want to carefully manage when we
+// call the callbacks, which can call into us again reentrantly.
+//
+// WatcherSignaler is designed to be placed on the stack as a RAII. After its
+// destructor runs, we might have executed aribitrary script.
+class DartLibraryLoader::WatcherSignaler {
+ public:
+  WatcherSignaler(DartLibraryLoader& loader,
+                  DartDependency* resolved_dependency)
+      : loader_(loader),
+        catcher_(adoptPtr(new DartDependencyCatcher(loader))),
+        resolved_dependency_(resolved_dependency) {}
+
+  ~WatcherSignaler() {
+    std::vector<DependencyWatcher*> completed_watchers;
+    for (const auto& watcher : loader_.dependency_watchers_) {
+      if (watcher->DidResolveDependency(resolved_dependency_,
+                                        catcher_->dependencies()))
+        completed_watchers.push_back(watcher.get());
+    }
+
+    // Notice that we remove the dependency catcher and extract all the
+    // callbacks before running any of them. We don't want to be re-entered
+    // below the callbacks and end up in an inconsistent state.
+    catcher_.clear();
+    std::vector<base::Closure> callbacks;
+    for (const auto& watcher : completed_watchers) {
+      callbacks.push_back(watcher->callback());
+      EraseUniquePtr(loader_.dependency_watchers_, watcher);
+    }
+
+    // Finally, run all the callbacks while touching only data on the stack.
+    for (const auto& callback : callbacks)
+      callback.Run();
+  }
+
+ private:
+  DartLibraryLoader& loader_;
+  OwnPtr<DartDependencyCatcher> catcher_;
+  DartDependency* resolved_dependency_;
+};
+
+DartLibraryLoader::DartLibraryLoader(DartState* dart_state)
+    : dart_state_(dart_state),
+      library_provider_(nullptr),
+      dependency_catcher_(nullptr) {
+}
+
+DartLibraryLoader::~DartLibraryLoader() {
+}
+
+Dart_Handle DartLibraryLoader::HandleLibraryTag(Dart_LibraryTag tag,
+                                                Dart_Handle library,
+                                                Dart_Handle url) {
+  DCHECK(Dart_IsLibrary(library));
+  DCHECK(Dart_IsString(url));
+  if (tag == Dart_kCanonicalizeUrl)
+    return DartState::Current()->library_loader().CanonicalizeURL(library, url);
+  if (tag == Dart_kImportTag) {
+    return DartState::Current()->library_loader().Import(library, url);
+  }
+  if (tag == Dart_kSourceTag) {
+    return DartState::Current()->library_loader().Source(library, url);
+  }
+  DCHECK(false);
+  return Dart_NewApiError("Unknown library tag.");
+}
+
+void DartLibraryLoader::WaitForDependencies(
+    const std::unordered_set<DartDependency*>& dependencies,
+    const base::Closure& callback) {
+  if (dependencies.empty())
+    return callback.Run();
+  dependency_watchers_.insert(
+      std::unique_ptr<DependencyWatcher>(
+          new DependencyWatcher(dependencies, callback)));
+}
+
+void DartLibraryLoader::LoadLibrary(const std::string& name) {
+  const auto& result = pending_libraries_.insert(std::make_pair(name, nullptr));
+  if (result.second) {
+    // New entry.
+    std::unique_ptr<Job> job = std::unique_ptr<Job>(new ImportJob(this, name));
+    result.first->second = job.get();
+    jobs_.insert(std::move(job));
+  }
+  if (dependency_catcher_)
+    dependency_catcher_->AddDependency(result.first->second);
+}
+
+Dart_Handle DartLibraryLoader::Import(Dart_Handle library, Dart_Handle url) {
+  LoadLibrary(StdStringFromDart(url));
+  return Dart_True();
+}
+
+Dart_Handle DartLibraryLoader::Source(Dart_Handle library, Dart_Handle url) {
+  std::unique_ptr<Job> job = std::unique_ptr<Job>(
+      new SourceJob(this, StdStringFromDart(url), library));
+  if (dependency_catcher_)
+    dependency_catcher_->AddDependency(job.get());
+  jobs_.insert(std::move(job));
+  return Dart_True();
+}
+
+Dart_Handle DartLibraryLoader::CanonicalizeURL(Dart_Handle library,
+                                               Dart_Handle url) {
+  return library_provider_->CanonicalizeURL(library, url);
+}
+
+void DartLibraryLoader::DidCompleteImportJob(
+    ImportJob* job,
+    const std::vector<uint8_t>& buffer) {
+  DartIsolateScope scope(dart_state_->isolate());
+  DartApiScope api_scope;
+
+  WatcherSignaler watcher_signaler(*this, job);
+
+  Dart_Handle result = Dart_LoadLibrary(
+      StdStringToDart(job->name()),
+      Dart_NewStringFromUTF8(buffer.data(), buffer.size()), 0, 0);
+  if (Dart_IsError(result)) {
+    LOG(ERROR) << "Error Loading " << job->name() << " "
+        << Dart_GetError(result);
+  }
+
+  pending_libraries_.erase(job->name());
+  EraseUniquePtr<Job>(jobs_, job);
+}
+
+void DartLibraryLoader::DidCompleteSourceJob(
+    SourceJob* job,
+    const std::vector<uint8_t>& buffer) {
+  DartIsolateScope scope(dart_state_->isolate());
+  DartApiScope api_scope;
+
+  WatcherSignaler watcher_signaler(*this, job);
+
+  Dart_Handle result = Dart_LoadSource(
+      Dart_HandleFromPersistent(job->library()),
+      StdStringToDart(job->name()),
+      Dart_NewStringFromUTF8(buffer.data(), buffer.size()), 0, 0);
+
+  if (Dart_IsError(result)) {
+    LOG(ERROR) << "Error Loading " << job->name() << " "
+        << Dart_GetError(result);
+  }
+
+  EraseUniquePtr<Job>(jobs_, job);
+}
+
+void DartLibraryLoader::DidFailJob(Job* job) {
+  DartIsolateScope scope(dart_state_->isolate());
+  DartApiScope api_scope;
+
+  WatcherSignaler watcher_signaler(*this, job);
+
+  LOG(ERROR) << "Library Load failed: " << job->name();
+  // TODO(eseidel): Call Dart_LibraryHandleError in the SourceJob case?
+
+  EraseUniquePtr<Job>(jobs_, job);
+}
+
+}  // namespace blink