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// Copyright (c) 2012 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_
#include <stdint.h>
#if defined(OS_WIN)
#include "base/win/windows_types.h"
#endif
#include <memory>
#include <string>
#include "build/build_config.h"
#include "ipc/ipc_message.h"
#include "ipc/ipc_message_support_export.h"
namespace base {
class WaitableEvent;
}
namespace IPC {
class MessageReplyDeserializer;
class IPC_MESSAGE_SUPPORT_EXPORT SyncMessage : public Message {
public:
SyncMessage(int32_t routing_id,
uint32_t type,
PriorityValue priority,
MessageReplyDeserializer* deserializer);
~SyncMessage() override;
// 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.
// This call enables message pumping behavior while waiting for a reply to
// this message.
void EnableMessagePumping() {
header()->flags |= PUMPING_MSGS_BIT;
}
// Indicates whether window messages should be pumped while waiting for a
// reply to this message.
bool ShouldPumpMessages() const {
return (header()->flags & PUMPING_MSGS_BIT) != 0;
}
// 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 base::PickleIterator 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);
std::unique_ptr<MessageReplyDeserializer> deserializer_;
};
// Used to deserialize parameters from a reply to a synchronous message
class IPC_MESSAGE_SUPPORT_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,
base::PickleIterator 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_
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