Use mojo for Chrome Loading, Part 1

content/browser/loader/mojo_async_resource_handler.h

Index: content/browser/loader/mojo_async_resource_handler.h
diff --git a/content/browser/loader/mojo_async_resource_handler.h b/content/browser/loader/mojo_async_resource_handler.h
new file mode 100644
index 0000000000000000000000000000000000000000..82ca56e258815fab1b245e79171a9b6f369cb546
--- /dev/null
+++ b/content/browser/loader/mojo_async_resource_handler.h
@@ -0,0 +1,121 @@
+// Copyright 2016 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.
+
+#ifndef CONTENT_BROWSER_LOADER_MOJO_ASYNC_RESOURCE_HANDLER_H_
+#define CONTENT_BROWSER_LOADER_MOJO_ASYNC_RESOURCE_HANDLER_H_
+
+#include <stdint.h>
+
+#include <memory>
+#include <string>
+
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/timer/timer.h"
+#include "content/browser/loader/resource_handler.h"
+#include "content/common/content_export.h"
+#include "content/common/url_loader.mojom.h"
+#include "mojo/message_pump/handle_watcher.h"
+#include "mojo/public/cpp/bindings/binding.h"
+#include "net/base/io_buffer.h"
+#include "url/gurl.h"
+
+namespace net {
+class URLRequest;
+}
+
+namespace content {
+class ResourceDispatcherHostImpl;
+class ResourceRequestInfoImpl;
+struct ResourceResponse;
+
+// Used to complete an asynchronous resource request in response to resource
+// load events from the resource dispatcher host. This class is used only
+// when LoadingWithMojo runtime enabled flag is enabled.
+//
+// TODO(yhirano): Implement redirects.
+// TODO(yhirano): Implement downloading to file.
+// TODO(yhirano): Add histograms.
+// TODO(yhirano): Set zoom level.
+// TODO(yhirano): Send cached metadata.
+//
+// This class can be inherited only for tests.
+class CONTENT_EXPORT MojoAsyncResourceHandler
+    : public ResourceHandler,
+      public NON_EXPORTED_BASE(mojom::URLLoader) {
+ public:
+  MojoAsyncResourceHandler(
+      net::URLRequest* request,
+      ResourceDispatcherHostImpl* rdh,
+      mojo::InterfaceRequest<mojom::URLLoader> mojo_request,
+      mojom::URLLoaderClientPtr url_loader_client);
+  ~MojoAsyncResourceHandler() override;
+
+  // ResourceHandler implementation:
+  bool OnRequestRedirected(const net::RedirectInfo& redirect_info,
+                           ResourceResponse* response,
+                           bool* defer) override;
+  bool OnResponseStarted(ResourceResponse* response, bool* defer) override;
+  bool OnWillStart(const GURL& url, bool* defer) override;
+  bool OnWillRead(scoped_refptr<net::IOBuffer>* buf,
+                  int* buf_size,
+                  int min_size) override;
+  bool OnReadCompleted(int bytes_read, bool* defer) override;
+  void OnResponseCompleted(const net::URLRequestStatus& status,
+                           const std::string& security_info,
+                           bool* defer) override;
+  void OnDataDownloaded(int bytes_downloaded) override;
+
+  // mojom::URLLoader implementation
+  void FollowRedirect() override;
+  void Cancel() override;
+
+  void ResumeForTesting();
+  static void SetAllocationSizeForTesting(size_t size);
+  static constexpr size_t kDefaultAllocationSize = 512 * 1024;
+
+ protected:
+  // These functions can be overriden only for tests.
+  virtual MojoResult BeginWrite(void** data, uint32_t* available);
+  virtual MojoResult EndWrite(uint32_t written);
+
+ private:
+  class SharedWriter;
+  class WriterIOBuffer;
+
+  // This funcion copies data stored in |buffer_| to |shared_writer_| and
+  // resets |buffer_| to a WriterIOBuffer when all bytes are copied. Returns
+  // true when done successfully.
+  bool CopyReadData(bool* defer);
+  // Allocates a WriterIOBuffer and set it to |*buf|. Returns true when done
+  // successfully.
+  bool AllocateBuffer(scoped_refptr<net::IOBufferWithSize>* buf, bool* defer);

[kinuko, 2016/08/03 18:20:07]

nit (optional): these methods are private so it's probably just fine as is but
I'd probably name these
CopyReadData --> CopyReadDataToWriter
AllocateBuffer --> AllocateBufferInWriter or AllocateBufferForWriter

or something like that, but up to you

[yhirano, 2016/08/04 12:50:51]

Done.

+
+  void Resume();
+  void OnDefer();
+  bool CheckForSufficientResource();
+  void OnWritable(MojoResult result);
+
+  ResourceDispatcherHostImpl* rdh_;
+  mojo::Binding<mojom::URLLoader> binding_;
+
+  bool has_checked_for_sufficient_resources_ = false;
+  bool sent_received_response_message_ = false;
+  bool is_using_io_buffer_not_from_writer_ = false;
+  base::TimeTicks response_started_ticks_;
+
+  mojo::common::HandleWatcher handle_watcher_;
+  std::unique_ptr<mojom::URLLoader> url_loader_;
+  mojom::URLLoaderClientPtr url_loader_client_;
+  scoped_refptr<net::IOBufferWithSize> buffer_;
+  size_t buffer_offset_ = 0;
+  size_t buffer_bytes_read_ = 0;
+  scoped_refptr<SharedWriter> shared_writer_;
+
+  DISALLOW_COPY_AND_ASSIGN(MojoAsyncResourceHandler);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_LOADER_MOJO_ASYNC_RESOURCE_HANDLER_H_