// Copyright (c) 2012 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "ipc/ipc_sync_message.h"
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#include <stdint.h>
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#include "base/atomic_sequence_num.h"
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#include "base/logging.h"
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#include "build/build_config.h"
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namespace {
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base::AtomicSequenceNumber g_next_id;
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} // namespace
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namespace IPC {
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#define kSyncMessageHeaderSize 4
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SyncMessage::SyncMessage(int32_t routing_id,
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uint32_t type,
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PriorityValue priority,
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MessageReplyDeserializer* deserializer)
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: Message(routing_id, type, priority),
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deserializer_(deserializer) {
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set_sync();
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set_unblock(true);
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// Add synchronous message data before the message payload.
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SyncHeader header;
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header.message_id = g_next_id.GetNext();
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WriteSyncHeader(this, header);
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}
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SyncMessage::~SyncMessage() = default;
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MessageReplyDeserializer* SyncMessage::GetReplyDeserializer() {
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DCHECK(deserializer_.get());
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return deserializer_.release();
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}
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bool SyncMessage::IsMessageReplyTo(const Message& msg, int request_id) {
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if (!msg.is_reply())
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return false;
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return GetMessageId(msg) == request_id;
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}
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base::PickleIterator SyncMessage::GetDataIterator(const Message* msg) {
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base::PickleIterator iter(*msg);
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if (!iter.SkipBytes(kSyncMessageHeaderSize))
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return base::PickleIterator();
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else
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return iter;
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}
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int SyncMessage::GetMessageId(const Message& msg) {
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if (!msg.is_sync() && !msg.is_reply())
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return 0;
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SyncHeader header;
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if (!ReadSyncHeader(msg, &header))
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return 0;
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return header.message_id;
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}
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Message* SyncMessage::GenerateReply(const Message* msg) {
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DCHECK(msg->is_sync());
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Message* reply = new Message(msg->routing_id(), IPC_REPLY_ID,
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msg->priority());
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reply->set_reply();
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SyncHeader header;
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// use the same message id, but this time reply bit is set
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header.message_id = GetMessageId(*msg);
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WriteSyncHeader(reply, header);
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return reply;
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}
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bool SyncMessage::ReadSyncHeader(const Message& msg, SyncHeader* header) {
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DCHECK(msg.is_sync() || msg.is_reply());
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base::PickleIterator iter(msg);
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bool result = iter.ReadInt(&header->message_id);
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if (!result) {
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NOTREACHED();
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return false;
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}
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return true;
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}
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bool SyncMessage::WriteSyncHeader(Message* msg, const SyncHeader& header) {
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DCHECK(msg->is_sync() || msg->is_reply());
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DCHECK(msg->payload_size() == 0);
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msg->WriteInt(header.message_id);
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// Note: if you add anything here, you need to update kSyncMessageHeaderSize.
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DCHECK(kSyncMessageHeaderSize == msg->payload_size());
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return true;
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}
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bool MessageReplyDeserializer::SerializeOutputParameters(const Message& msg) {
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return SerializeOutputParameters(msg, SyncMessage::GetDataIterator(&msg));
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}
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} // namespace IPC
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