// 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. #include "ipc/ipc_sync_message.h" #include #include "base/atomic_sequence_num.h" #include "base/check.h" #include "base/notreached.h" #include "build/build_config.h" namespace { base::AtomicSequenceNumber g_next_id; } // namespace namespace IPC { #define kSyncMessageHeaderSize 4 SyncMessage::SyncMessage(int32_t routing_id, uint32_t type, PriorityValue priority, MessageReplyDeserializer* deserializer) : Message(routing_id, type, priority), deserializer_(deserializer) { set_sync(); set_unblock(true); // Add synchronous message data before the message payload. SyncHeader header; header.message_id = g_next_id.GetNext(); WriteSyncHeader(this, header); } SyncMessage::~SyncMessage() = default; MessageReplyDeserializer* SyncMessage::GetReplyDeserializer() { DCHECK(deserializer_.get()); return deserializer_.release(); } bool SyncMessage::IsMessageReplyTo(const Message& msg, int request_id) { if (!msg.is_reply()) return false; return GetMessageId(msg) == request_id; } base::PickleIterator SyncMessage::GetDataIterator(const Message* msg) { base::PickleIterator iter(*msg); if (!iter.SkipBytes(kSyncMessageHeaderSize)) return base::PickleIterator(); else return iter; } int SyncMessage::GetMessageId(const Message& msg) { if (!msg.is_sync() && !msg.is_reply()) return 0; SyncHeader header; if (!ReadSyncHeader(msg, &header)) return 0; return header.message_id; } Message* SyncMessage::GenerateReply(const Message* msg) { DCHECK(msg->is_sync()); Message* reply = new Message(msg->routing_id(), IPC_REPLY_ID, msg->priority()); reply->set_reply(); SyncHeader header; // use the same message id, but this time reply bit is set header.message_id = GetMessageId(*msg); WriteSyncHeader(reply, header); return reply; } bool SyncMessage::ReadSyncHeader(const Message& msg, SyncHeader* header) { DCHECK(msg.is_sync() || msg.is_reply()); base::PickleIterator iter(msg); bool result = iter.ReadInt(&header->message_id); if (!result) { NOTREACHED(); return false; } return true; } bool SyncMessage::WriteSyncHeader(Message* msg, const SyncHeader& header) { DCHECK(msg->is_sync() || msg->is_reply()); DCHECK(msg->payload_size() == 0); msg->WriteInt(header.message_id); // Note: if you add anything here, you need to update kSyncMessageHeaderSize. DCHECK(kSyncMessageHeaderSize == msg->payload_size()); return true; } bool MessageReplyDeserializer::SerializeOutputParameters(const Message& msg) { return SerializeOutputParameters(msg, SyncMessage::GetDataIterator(&msg)); } } // namespace IPC