Hidehiko Abe | b268b43 | 2018-04-24 01:37:19 +0900 | [diff] [blame] | 1 | // Copyright (c) 2012 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 IPC_IPC_SYNC_MESSAGE_H_ |
| 6 | #define IPC_IPC_SYNC_MESSAGE_H_ |
| 7 | |
| 8 | #include <stdint.h> |
| 9 | |
| 10 | #if defined(OS_WIN) |
| 11 | #include <windows.h> |
| 12 | #endif |
| 13 | |
| 14 | #include <memory> |
| 15 | #include <string> |
| 16 | |
| 17 | #include "build/build_config.h" |
| 18 | #include "ipc/ipc_message.h" |
| 19 | |
| 20 | namespace base { |
| 21 | class WaitableEvent; |
| 22 | } |
| 23 | |
| 24 | namespace IPC { |
| 25 | |
| 26 | class MessageReplyDeserializer; |
| 27 | |
| 28 | class IPC_EXPORT SyncMessage : public Message { |
| 29 | public: |
| 30 | SyncMessage(int32_t routing_id, |
| 31 | uint32_t type, |
| 32 | PriorityValue priority, |
| 33 | MessageReplyDeserializer* deserializer); |
| 34 | ~SyncMessage() override; |
| 35 | |
| 36 | // Call this to get a deserializer for the output parameters. |
| 37 | // Note that this can only be called once, and the caller is responsible |
| 38 | // for deleting the deserializer when they're done. |
| 39 | MessageReplyDeserializer* GetReplyDeserializer(); |
| 40 | |
| 41 | // If this message can cause the receiver to block while waiting for user |
| 42 | // input (i.e. by calling MessageBox), then the caller needs to pump window |
| 43 | // messages and dispatch asynchronous messages while waiting for the reply. |
| 44 | // This call enables message pumping behavior while waiting for a reply to |
| 45 | // this message. |
| 46 | void EnableMessagePumping() { |
| 47 | header()->flags |= PUMPING_MSGS_BIT; |
| 48 | } |
| 49 | |
| 50 | // Indicates whether window messages should be pumped while waiting for a |
| 51 | // reply to this message. |
| 52 | bool ShouldPumpMessages() const { |
| 53 | return (header()->flags & PUMPING_MSGS_BIT) != 0; |
| 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 base::PickleIterator 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 | std::unique_ptr<MessageReplyDeserializer> deserializer_; |
| 79 | }; |
| 80 | |
| 81 | // Used to deserialize parameters from a reply to a synchronous message |
| 82 | class IPC_EXPORT MessageReplyDeserializer { |
| 83 | public: |
| 84 | virtual ~MessageReplyDeserializer() {} |
| 85 | bool SerializeOutputParameters(const Message& msg); |
| 86 | private: |
| 87 | // Derived classes need to implement this, using the given iterator (which |
| 88 | // is skipped past the header for synchronous messages). |
| 89 | virtual bool SerializeOutputParameters(const Message& msg, |
| 90 | base::PickleIterator iter) = 0; |
| 91 | }; |
| 92 | |
| 93 | // When sending a synchronous message, this structure contains an object |
| 94 | // that knows how to deserialize the response. |
| 95 | struct PendingSyncMsg { |
| 96 | PendingSyncMsg(int id, MessageReplyDeserializer* d, base::WaitableEvent* e) |
| 97 | : id(id), deserializer(d), done_event(e), send_result(false) {} |
| 98 | |
| 99 | int id; |
| 100 | MessageReplyDeserializer* deserializer; |
| 101 | base::WaitableEvent* done_event; |
| 102 | bool send_result; |
| 103 | }; |
| 104 | |
| 105 | } // namespace IPC |
| 106 | |
| 107 | #endif // IPC_IPC_SYNC_MESSAGE_H_ |