Allow synchronous messages to be sent from threads other than the main thread...

ipc/ipc_sync_message.h

-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Copyright (c) 2010 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 IPC_IPC_SYNC_MESSAGE_H_
 #define IPC_IPC_SYNC_MESSAGE_H_
 
 #if defined(OS_WIN)
 #include <windows.h>
 #endif
 #include <string>
@@ skipping 58 matching lines @@
   struct SyncHeader {
     // unique ID (unique per sender)
     int message_id;
   };
 
   static bool ReadSyncHeader(const Message& msg, SyncHeader* header);
   static bool WriteSyncHeader(Message* msg, const SyncHeader& header);
 
   MessageReplyDeserializer* deserializer_;
   base::WaitableEvent* pump_messages_event_;
-
-  static uint32 next_id_;  // for generation of unique ids
 };
 
 // Used to deserialize parameters from a reply to a synchronous message
 class MessageReplyDeserializer {
  public:
   virtual ~MessageReplyDeserializer() {}
   bool SerializeOutputParameters(const Message& msg);
  private:
   // Derived classes need to implement this, using the given iterator (which
   // is skipped past the header for synchronous messages).
   virtual bool SerializeOutputParameters(const Message& msg, void* iter) = 0;
 };
 
+// When sending a synchronous message, this structure contains an object
+// that knows how to deserialize the response.
+struct PendingSyncMsg {
+  PendingSyncMsg(int id,
+                 MessageReplyDeserializer* d,
+                 base::WaitableEvent* e)
+      : id(id), deserializer(d), done_event(e), send_result(false) { }
+  int id;
+  MessageReplyDeserializer* deserializer;
+  base::WaitableEvent* done_event;
+  bool send_result;
+};
+
 }  // namespace IPC
 
 #endif  // IPC_IPC_SYNC_MESSAGE_H_