michael@0: // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
michael@0: // Use of this source code is governed by a BSD-style license that can be
michael@0: // found in the LICENSE file.
michael@0: 
michael@0: #ifndef CHROME_COMMON_IPC_SYNC_MESSAGE_H__
michael@0: #define CHROME_COMMON_IPC_SYNC_MESSAGE_H__
michael@0: 
michael@0: #if defined(OS_WIN)
michael@0: #include <windows.h>
michael@0: #endif
michael@0: #include <string>
michael@0: #include "base/basictypes.h"
michael@0: #include "chrome/common/ipc_message.h"
michael@0: 
michael@0: namespace base {
michael@0: class WaitableEvent;
michael@0: }
michael@0: 
michael@0: namespace IPC {
michael@0: 
michael@0: class MessageReplyDeserializer;
michael@0: 
michael@0: class SyncMessage : public Message {
michael@0:  public:
michael@0:   SyncMessage(int32_t routing_id, uint16_t type, PriorityValue priority,
michael@0:               MessageReplyDeserializer* deserializer);
michael@0: 
michael@0:   // Call this to get a deserializer for the output parameters.
michael@0:   // Note that this can only be called once, and the caller is responsible
michael@0:   // for deleting the deserializer when they're done.
michael@0:   MessageReplyDeserializer* GetReplyDeserializer();
michael@0: 
michael@0:   // If this message can cause the receiver to block while waiting for user
michael@0:   // input (i.e. by calling MessageBox), then the caller needs to pump window
michael@0:   // messages and dispatch asynchronous messages while waiting for the reply.
michael@0:   // If this event is passed in, then window messages will start being pumped
michael@0:   // when it's set.  Note that this behavior will continue even if the event is
michael@0:   // later reset.  The event must be valid until after the Send call returns.
michael@0:   void set_pump_messages_event(base::WaitableEvent* event) {
michael@0:     pump_messages_event_ = event;
michael@0:     if (event) {
michael@0:       header()->flags |= PUMPING_MSGS_BIT;
michael@0:     } else {
michael@0:       header()->flags &= ~PUMPING_MSGS_BIT;
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   // Call this if you always want to pump messages.  You can call this method
michael@0:   // or set_pump_messages_event but not both.
michael@0:   void EnableMessagePumping();
michael@0: 
michael@0:   base::WaitableEvent* pump_messages_event() const {
michael@0:     return pump_messages_event_;
michael@0:   }
michael@0: 
michael@0:   // Returns true if the message is a reply to the given request id.
michael@0:   static bool IsMessageReplyTo(const Message& msg, int request_id);
michael@0: 
michael@0:   // Given a reply message, returns an iterator to the beginning of the data
michael@0:   // (i.e. skips over the synchronous specific data).
michael@0:   static void* GetDataIterator(const Message* msg);
michael@0: 
michael@0:   // Given a synchronous message (or its reply), returns its id.
michael@0:   static int GetMessageId(const Message& msg);
michael@0: 
michael@0:   // Generates a reply message to the given message.
michael@0:   static Message* GenerateReply(const Message* msg);
michael@0: 
michael@0:  private:
michael@0:   struct SyncHeader {
michael@0:     // unique ID (unique per sender)
michael@0:     int message_id;
michael@0:   };
michael@0: 
michael@0:   static bool ReadSyncHeader(const Message& msg, SyncHeader* header);
michael@0:   static bool WriteSyncHeader(Message* msg, const SyncHeader& header);
michael@0: 
michael@0:   MessageReplyDeserializer* deserializer_;
michael@0:   base::WaitableEvent* pump_messages_event_;
michael@0: 
michael@0:   static uint32_t next_id_;  // for generation of unique ids
michael@0: };
michael@0: 
michael@0: // Used to deserialize parameters from a reply to a synchronous message
michael@0: class MessageReplyDeserializer {
michael@0:  public:
michael@0:   bool SerializeOutputParameters(const Message& msg);
michael@0:   virtual ~MessageReplyDeserializer() {}
michael@0:  private:
michael@0:   // Derived classes need to implement this, using the given iterator (which
michael@0:   // is skipped past the header for synchronous messages).
michael@0:   virtual bool SerializeOutputParameters(const Message& msg, void* iter) = 0;
michael@0: };
michael@0: 
michael@0: }  // namespace IPC
michael@0: 
michael@0: #endif  // CHROME_COMMON_IPC_SYNC_MESSAGE_H__