1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 #ifndef IPC_IPC_SYNC_MESSAGE_H_
6 #define IPC_IPC_SYNC_MESSAGE_H_
13 #include "base/basictypes.h"
14 #include "ipc/ipc_message.h"
22 class MessageReplyDeserializer;
24 class IPC_EXPORT SyncMessage : public Message {
26 SyncMessage(int32 routing_id, uint32 type, PriorityValue priority,
27 MessageReplyDeserializer* deserializer);
29 // Call this to get a deserializer for the output parameters.
30 // Note that this can only be called once, and the caller is responsible
31 // for deleting the deserializer when they're done.
32 MessageReplyDeserializer* GetReplyDeserializer();
34 // If this message can cause the receiver to block while waiting for user
35 // input (i.e. by calling MessageBox), then the caller needs to pump window
36 // messages and dispatch asynchronous messages while waiting for the reply.
37 // If this event is passed in, then window messages will start being pumped
38 // when it's set. Note that this behavior will continue even if the event is
39 // later reset. The event must be valid until after the Send call returns.
40 void set_pump_messages_event(base::WaitableEvent* event) {
41 pump_messages_event_ = event;
43 header()->flags |= PUMPING_MSGS_BIT;
45 header()->flags &= ~PUMPING_MSGS_BIT;
49 // Call this if you always want to pump messages. You can call this method
50 // or set_pump_messages_event but not both.
51 void EnableMessagePumping();
53 base::WaitableEvent* pump_messages_event() const {
54 return pump_messages_event_;
57 // Returns true if the message is a reply to the given request id.
58 static bool IsMessageReplyTo(const Message& msg, int request_id);
60 // Given a reply message, returns an iterator to the beginning of the data
61 // (i.e. skips over the synchronous specific data).
62 static void* GetDataIterator(const Message* msg);
64 // Given a synchronous message (or its reply), returns its id.
65 static int GetMessageId(const Message& msg);
67 // Generates a reply message to the given message.
68 static Message* GenerateReply(const Message* msg);
72 // unique ID (unique per sender)
76 static bool ReadSyncHeader(const Message& msg, SyncHeader* header);
77 static bool WriteSyncHeader(Message* msg, const SyncHeader& header);
79 MessageReplyDeserializer* deserializer_;
80 base::WaitableEvent* pump_messages_event_;
83 // Used to deserialize parameters from a reply to a synchronous message
84 class IPC_EXPORT MessageReplyDeserializer {
86 virtual ~MessageReplyDeserializer() {}
87 bool SerializeOutputParameters(const Message& msg);
89 // Derived classes need to implement this, using the given iterator (which
90 // is skipped past the header for synchronous messages).
91 virtual bool SerializeOutputParameters(const Message& msg, void* iter) = 0;
94 // When sending a synchronous message, this structure contains an object
95 // that knows how to deserialize the response.
96 struct PendingSyncMsg {
97 PendingSyncMsg(int id,
98 MessageReplyDeserializer* d,
99 base::WaitableEvent* e)
100 : id(id), deserializer(d), done_event(e), send_result(false) { }
102 MessageReplyDeserializer* deserializer;
103 base::WaitableEvent* done_event;
109 #endif // IPC_IPC_SYNC_MESSAGE_H_