Implement websocket throttling.

net/socket_stream/socket_stream_throttle.h

+// Copyright (c) 2009 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 NET_SOCKET_STREAM_SOCKET_STREAM_THROTTLE_H_
+#define NET_SOCKET_STREAM_SOCKET_STREAM_THROTTLE_H_
+
+#include <string>
+
+#include "base/basictypes.h"
+#include "net/base/completion_callback.h"
+#include "net/base/net_errors.h"
+
+namespace net {
+
+class SocketStream;
+
+// Abstract interface to throttle SocketStream per URL scheme.
+// Each URL scheme (protocol) could define own SocketStreamThrottle.
+// These methods will be called on IO thread.
+class SocketStreamThrottle {
+ public:
+  // Called when |socket| is about to open connection.
+  // Returns net::OK if the connection can open now.
+  // Returns net::ERR_IO_PENDING if the connection should wait.  In this case,
+  // |callback| will be called when it's ready to open connection.
+  virtual int OnStartOpenConnection(SocketStream* socket,
+                                    CompletionCallback* callback) {
+    // No throttle by default.
+    return OK;
+  }
+
+  // Called when |socket| read |len| bytes of |data|.
+  // May wake up another waiting socket.
+  // Returns net::OK if |socket| can continue to run.
+  // Returns net::ERR_IO_PENDING if |socket| should suspend to run.  In this
+  // case, |callback| will be called when it's ready to resume running.
+  virtual int OnRead(SocketStream* socket, const char* data, int len,
+                     CompletionCallback* callback) {
+    // No throttle by default.
+    return OK;
+  }
+
+  // Called when |socket| wrote |len| bytes of |data|.
+  // May wake up another waiting socket.
+  // Returns net::OK if |socket| can continue to run.
+  // Returns net::ERR_IO_PENDING if |socket| should suspend to run.  In this
+  // case, |callback| will be called when it's ready to resume running.
+  virtual int OnWrite(SocketStream* socket, const char* data, int len,
+                      CompletionCallback* callback) {
+    // No throttle by default.
+    return OK;
+  }
+
+  // Called when |socket| is closed.
+  // May wake up another waiting socket.
+  virtual void OnClose(SocketStream* socket) {}
+
+  // Gets SocketStreamThrottle for URL |scheme|.
+  // Doesn't pass ownership of the SocketStreamThrottle.
+  static SocketStreamThrottle* GetSocketStreamThrottleForScheme(
+      const std::string& scheme);
+
+  // Registers |throttle| for URL |scheme|.
+  // Doesn't take ownership of |throttle|.  Typically |throttle| is
+  // singleton instance.
+  static void RegisterSocketStreamThrottle(
+      const std::string& scheme,
+      SocketStreamThrottle* throttle);
+
+ protected:
+  SocketStreamThrottle() {}
+  virtual ~SocketStreamThrottle() {}
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(SocketStreamThrottle);
+};
+
+}  // namespace net
+
+#endif  // NET_SOCKET_STREAM_SOCKET_STREAM_THROTTLE_H_