Initial import of the Chrome Frame codebase. Integration in chrome.gyp coming...

chrome_frame/sync_msg_reply_dispatcher.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 CHROME_FRAME_SYNC_MSG_REPLY_DISPATCHER_H_
+#define CHROME_FRAME_SYNC_MSG_REPLY_DISPATCHER_H_
+
+#include <deque>
+
+#include "base/lock.h"
+#include "ipc/ipc_channel_proxy.h"
+
+// Base class used to allow synchronous IPC messages to be sent and
+// received in an asynchronous manner. To use this class add it as a filter to
+// your IPC channel using ChannelProxy::AddFilter(). From then on, before
+// sending a synchronous message, call SyncMessageReplyDispatcher::Push() with
+// a callback and a key. This class will then handle the message response and
+// will call the callback when it is received.
+//
+// This class is intended to be extended by classes implementing
+// HandleMessageType with delegation for the messages they expect to receive in
+// cases where you care about the return values of synchronous messages.
+//
+// Sample usage pattern:
+//
+// // Add handling for desired message types.
+// class SyncMessageReplyDispatcherImpl : public SyncMessageReplyDispatcher {
+//   virtual bool HandleMessageType(const IPC::Message& msg,
+//                                  const MessageSent& origin) {
+//    switch (origin.type) {
+//      case AutomationMsg_CreateExternalTab::ID:
+//        InvokeCallback<Tuple3<HWND, HWND, int> >(msg, origin);
+//        break;
+//     [HANDLING FOR OTHER EXPECTED MESSAGE TYPES]
+//   }
+// }
+//
+// // Add the filter
+// IPC::SyncChannel channel_;
+// channel_.AddFilter(new SyncMessageReplyDispatcherImpl());
+//
+// sync_->Push(msg, NewCallback(this, CallbackMethod, this);
+// channel_->ChannelProxy::Send(msg);
+//
+class SyncMessageReplyDispatcher : public IPC::ChannelProxy::MessageFilter {
+ public:
+  SyncMessageReplyDispatcher() {}
+  void Push(IPC::SyncMessage* msg, void* callback, void* key);
+  void Cancel(void* key);
+
+ protected:
+  struct MessageSent {
+    MessageSent() {}
+    MessageSent(int id, uint16 type, void* callback, void* key)
+      : id(id), callback(callback), type(type), key(key) {}
+    int id;
+    void* callback;
+    void* key;
+    uint16 type;
+  };
+
+  typedef std::deque<MessageSent> PendingSyncMessageQueue;
+
+  bool Pop(const IPC::Message& msg, MessageSent* t);
+  virtual bool OnMessageReceived(const IPC::Message& msg);
+
+  // Child classes must implement a handler for the message types they are
+  // interested in handling responses for. If you don't care about the replies
+  // to any of the sync messages you are handling, then you don't have to
+  // implement this.
+  virtual bool HandleMessageType(const IPC::Message& msg,
+                                 const MessageSent& origin);
+
+  template <typename T>
+  void InvokeCallback(const IPC::Message& msg, const MessageSent& origin) {
+    // Ensure we delete the callback
+    scoped_ptr<CallbackRunner<T> > c(
+        reinterpret_cast<CallbackRunner<T>*>(origin.callback));
+    if (origin.key == NULL) {  // Canceled
+      return;
+    }
+
+    T tmp;  // Acts as "initializer" for output parameters.
+    IPC::ParamDeserializer<T> deserializer(tmp);
+    if (deserializer.MessageReplyDeserializer::SerializeOutputParameters(msg)) {
+      c->RunWithParams(deserializer.out_);
+    } else {
+      // TODO(stoyan): How to handle errors?
+    }
+  }
+
+  PendingSyncMessageQueue message_queue_;
+  Lock message_queue_lock_;
+};
+
+#endif  // CHROME_FRAME_SYNC_MSG_REPLY_DISPATCHER_H_