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+// Copyright (c) 2011 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_
+#pragma once
+
+#if defined(OS_WIN)
+#include <windows.h>
+#endif
+#include <string>
+#include "base/basictypes.h"
+#include "ipc/ipc_message.h"
+
+namespace base {
+class WaitableEvent;
+}
+
+namespace IPC {
+
+class MessageReplyDeserializer;
+
+class IPC_EXPORT SyncMessage : public Message {
+ public:
+ SyncMessage(int32 routing_id, uint32 type, PriorityValue priority,
+ MessageReplyDeserializer* deserializer);
+
+ // Call this to get a deserializer for the output parameters.
+ // Note that this can only be called once, and the caller is responsible
+ // for deleting the deserializer when they're done.
+ MessageReplyDeserializer* GetReplyDeserializer();
+
+ // If this message can cause the receiver to block while waiting for user
+ // input (i.e. by calling MessageBox), then the caller needs to pump window
+ // messages and dispatch asynchronous messages while waiting for the reply.
+ // If this event is passed in, then window messages will start being pumped
+ // when it's set. Note that this behavior will continue even if the event is
+ // later reset. The event must be valid until after the Send call returns.
+ void set_pump_messages_event(base::WaitableEvent* event) {
+ pump_messages_event_ = event;
+ if (event) {
+ header()->flags |= PUMPING_MSGS_BIT;
+ } else {
+ header()->flags &= ~PUMPING_MSGS_BIT;
+ }
+ }
+
+ // Call this if you always want to pump messages. You can call this method
+ // or set_pump_messages_event but not both.
+ void EnableMessagePumping();
+
+ base::WaitableEvent* pump_messages_event() const {
+ return pump_messages_event_;
+ }
+
+ // Returns true if the message is a reply to the given request id.
+ static bool IsMessageReplyTo(const Message& msg, int request_id);
+
+ // Given a reply message, returns an iterator to the beginning of the data
+ // (i.e. skips over the synchronous specific data).
+ static void* GetDataIterator(const Message* msg);
+
+ // Given a synchronous message (or its reply), returns its id.
+ static int GetMessageId(const Message& msg);
+
+ // Generates a reply message to the given message.
+ static Message* GenerateReply(const Message* msg);
+
+ private:
+ 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_;
+};
+
+// Used to deserialize parameters from a reply to a synchronous message
+class IPC_EXPORT 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_