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1 // Copyright (c) 2006-2008 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. | |
4 | |
5 #ifndef CHROME_COMMON_IPC_SYNC_MESSAGE_H__ | |
6 #define CHROME_COMMON_IPC_SYNC_MESSAGE_H__ | |
7 | |
8 #if defined(OS_WIN) | |
9 #include <windows.h> | |
10 #endif | |
11 #include <string> | |
12 #include "base/basictypes.h" | |
13 #include "chrome/common/ipc_message.h" | |
14 | |
15 namespace base { | |
16 class WaitableEvent; | |
17 } | |
18 | |
19 namespace IPC { | |
20 | |
21 class MessageReplyDeserializer; | |
22 | |
23 class SyncMessage : public Message { | |
24 public: | |
25 SyncMessage(int32 routing_id, uint16 type, PriorityValue priority, | |
26 MessageReplyDeserializer* deserializer); | |
27 | |
28 // Call this to get a deserializer for the output parameters. | |
29 // Note that this can only be called once, and the caller is responsible | |
30 // for deleting the deserializer when they're done. | |
31 MessageReplyDeserializer* GetReplyDeserializer(); | |
32 | |
33 // If this message can cause the receiver to block while waiting for user | |
34 // input (i.e. by calling MessageBox), then the caller needs to pump window | |
35 // messages and dispatch asynchronous messages while waiting for the reply. | |
36 // If this event is passed in, then window messages will start being pumped | |
37 // when it's set. Note that this behavior will continue even if the event is | |
38 // later reset. The event must be valid until after the Send call returns. | |
39 void set_pump_messages_event(base::WaitableEvent* event) { | |
40 pump_messages_event_ = event; | |
41 if (event) { | |
42 header()->flags |= PUMPING_MSGS_BIT; | |
43 } else { | |
44 header()->flags &= ~PUMPING_MSGS_BIT; | |
45 } | |
46 } | |
47 | |
48 // Call this if you always want to pump messages. You can call this method | |
49 // or set_pump_messages_event but not both. | |
50 void EnableMessagePumping(); | |
51 | |
52 base::WaitableEvent* pump_messages_event() const { | |
53 return pump_messages_event_; | |
54 } | |
55 | |
56 // Returns true if the message is a reply to the given request id. | |
57 static bool IsMessageReplyTo(const Message& msg, int request_id); | |
58 | |
59 // Given a reply message, returns an iterator to the beginning of the data | |
60 // (i.e. skips over the synchronous specific data). | |
61 static void* GetDataIterator(const Message* msg); | |
62 | |
63 // Given a synchronous message (or its reply), returns its id. | |
64 static int GetMessageId(const Message& msg); | |
65 | |
66 // Generates a reply message to the given message. | |
67 static Message* GenerateReply(const Message* msg); | |
68 | |
69 private: | |
70 struct SyncHeader { | |
71 // unique ID (unique per sender) | |
72 int message_id; | |
73 }; | |
74 | |
75 static bool ReadSyncHeader(const Message& msg, SyncHeader* header); | |
76 static bool WriteSyncHeader(Message* msg, const SyncHeader& header); | |
77 | |
78 MessageReplyDeserializer* deserializer_; | |
79 base::WaitableEvent* pump_messages_event_; | |
80 | |
81 static uint32 next_id_; // for generation of unique ids | |
82 }; | |
83 | |
84 // Used to deserialize parameters from a reply to a synchronous message | |
85 class MessageReplyDeserializer { | |
86 public: | |
87 bool SerializeOutputParameters(const Message& msg); | |
88 private: | |
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; | |
92 }; | |
93 | |
94 } // namespace IPC | |
95 | |
96 #endif // CHROME_COMMON_IPC_SYNC_MESSAGE_H__ | |
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