Implement content::WebSocketBlobSender

content/browser/renderer_host/websocket_blob_sender.h

+// 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_RENDERER_HOST_WEBSOCKET_BLOB_SENDER_H_
+#define CONTENT_BROWSER_RENDERER_HOST_WEBSOCKET_BLOB_SENDER_H_
+
+#include <stdint.h>
+#include <string>
+#include <vector>
+
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "content/common/content_export.h"
+#include "net/base/completion_callback.h"
+#include "net/websockets/websocket_event_interface.h"
+
+namespace base {
+class SingleThreadTaskRunner;
+}
+
+namespace net {
+class IOBuffer;
+}
+
+namespace storage {
+class BlobReader;
+class BlobStorageContext;
+class FileSystemContext;
+}
+
+namespace content {
+
+class WebSocketHost;
+
+class CONTENT_EXPORT WebSocketBlobSender {
+ public:
+  // An abstraction of the WebSocketChannel this object will send frames to.
+  class Channel {
+   public:
+    using ChannelState = net::WebSocketEventInterface::ChannelState;
+
+    Channel() {}
+    virtual ~Channel() {}
+
+    // The currently available quota for sending. It must not decrease without
+    // SendFrame() being called.
+    virtual int GetSendQuota() const = 0;
+
+    // Send a binary frame. |fin| is true for the final frame of the message.
+    // |data| is the contents of the frame. data.size() must be less than
+    // GetSendQuota(). If this call returns CHANNEL_DELETED, WebSocketBlobSender
+    // will assume that it has been deleted and return without calling any
+    // callbacks or accessing any other member data.
+    virtual ChannelState SendFrame(bool fin, const std::vector<char>& data) = 0;

[dcheng, 2016/01/20 08:30:06]

bool is_final_frame would be more descriptive.

[Adam Rice, 2016/01/20 17:11:20]

The names were originally based on the terminology in the spec (RFC 6455). At
this layer of abstraction it doesn't matter whether you're familiar with the
spec or not, but then I'd have to figure out where to draw the line where we
start caring about the spec terminology. I'm not sure where that would be.

+
+   private:
+    DISALLOW_COPY_AND_ASSIGN(Channel);
+  };
+
+  explicit WebSocketBlobSender(scoped_ptr<Channel> channel);
+  ~WebSocketBlobSender();
+
+  // Checks that the blob identified by |uuid| exists, has the size
+  // |expected_size| and then starts sending it via |channel_|. Returns
+  // ERR_IO_PENDING to indicate that |callback| will be called later with the
+  // result. net::OK indicates synchronous success. Any other net error code
+  // indicates synchronous failure. This method may result in the destruction of
+  // the channel, in which case |*channel_state| will be set to CHANNEL_DELETED.
+  int Start(const std::string& uuid,
+            uint64_t expected_size,
+            storage::BlobStorageContext* context,
+            storage::FileSystemContext* file_system_context,
+            base::SingleThreadTaskRunner* file_task_runner,
+            net::WebSocketEventInterface::ChannelState* channel_state,
+            const net::CompletionCallback& callback);
+
+  // Sends more data if the object was waiting for quota and the new value of
+  // GetSendQuota() is large enough.
+  void OnNewSendQuota();
+
+  uint64_t expected_size() const { return expected_size_; }
+
+  // ActualSize() should only be called after completion: ie. Start() returned a
+  // value other than ERR_IO_PENDING or |callback_| has been called.
+  uint64_t ActualSize() const;
+
+ private:
+  // State proceeds through STATE_READ_SIZE and STATE_READ_SIZE_COMPLETE, then
+  // loops STATE_WAIT_FOR_QUOTA -> STATE_WAIT_FOR_QUOTA_COMPLETE -> STATE_READ
+  // -> STATE_READ_COMPLETE -> STATE_WAIT_FOR_QUOTA until the Blob is completely
+  // sent.
+  enum State {

[dcheng, 2016/01/20 08:30:06]

enum class? Then the members can just be named NONE, READ_SIZE, etc.

[Adam Rice, 2016/01/20 17:11:20]

Done.

+    STATE_NONE,
+    STATE_READ_SIZE,
+    STATE_READ_SIZE_COMPLETE,
+    STATE_WAIT_FOR_QUOTA,
+    STATE_WAIT_FOR_QUOTA_COMPLETE,
+    STATE_READ,
+    STATE_READ_COMPLETE,
+  };
+
+  void OnIOComplete(int rv);
+  void OnSizeCalculated(int rv);
+  // |channel_state| should point to CHANNEL_ALIVE when called. If it is
+  // CHANNEL_DELETED on return, the object has been deleted.
+  int DoLoop(int result, Channel::ChannelState* channel_state);
+  void DoLoopAsync(int result);
+  int DoReadSize();
+  int DoReadSizeComplete(int result);
+  int DoWaitForQuota();
+  int DoWaitForQuotaComplete();
+  int DoRead();
+  int DoReadComplete(int result, Channel::ChannelState* channel_state);
+
+  State next_state_ = STATE_NONE;
+  uint64_t expected_size_ = 0;
+  uint64_t bytes_left_ = 0;
+  net::CompletionCallback callback_;
+  scoped_refptr<net::IOBuffer> buffer_;
+  scoped_ptr<storage::BlobReader> reader_;
+  const scoped_ptr<Channel> channel_;
+
+  DISALLOW_COPY_AND_ASSIGN(WebSocketBlobSender);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_RENDERER_HOST_WEBSOCKET_BLOB_SENDER_H_