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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_CHANNEL_NACL_H_
- #define IPC_IPC_CHANNEL_NACL_H_
- #include <memory>
- #include <string>
- #include "base/containers/circular_deque.h"
- #include "base/memory/weak_ptr.h"
- #include "base/process/process.h"
- #include "base/threading/simple_thread.h"
- #include "ipc/ipc_channel.h"
- #include "ipc/ipc_channel_reader.h"
- namespace IPC {
- class MessageAttachment;
- // Contains the results from one call to imc_recvmsg (data and file
- // descriptors).
- struct MessageContents;
- // Similar to the ChannelPosix but for Native Client code.
- // This is somewhat different because sendmsg/recvmsg here do not follow POSIX
- // semantics. Instead, they are implemented by a custom embedding of
- // NaClDescCustom. See NaClIPCAdapter for the trusted-side implementation.
- //
- // We don't need to worry about complicated set up and READWRITE mode for
- // sharing handles. We also currently do not support passing file descriptors or
- // named pipes, and we use background threads to emulate signaling when we can
- // read or write without blocking.
- class ChannelNacl : public Channel,
- public internal::ChannelReader {
- public:
- ChannelNacl() = delete;
- // Mirror methods of Channel, see ipc_channel.h for description.
- ChannelNacl(const IPC::ChannelHandle& channel_handle,
- Mode mode,
- Listener* listener);
- ChannelNacl(const ChannelNacl&) = delete;
- ChannelNacl& operator=(const ChannelNacl&) = delete;
- ~ChannelNacl() override;
- // Channel implementation.
- bool Connect() override;
- void Close() override;
- bool Send(Message* message) override;
- // Posted to the main thread by ReaderThreadRunner.
- void DidRecvMsg(std::unique_ptr<MessageContents> contents);
- void ReadDidFail();
- private:
- class ReaderThreadRunner;
- bool CreatePipe(const IPC::ChannelHandle& channel_handle);
- bool ProcessOutgoingMessages();
- void CallOnChannelConnected();
- // ChannelReader implementation.
- ReadState ReadData(char* buffer,
- int buffer_len,
- int* bytes_read) override;
- bool ShouldDispatchInputMessage(Message* msg) override;
- bool GetAttachments(Message* msg) override;
- bool DidEmptyInputBuffers() override;
- void HandleInternalMessage(const Message& msg) override;
- Mode mode_;
- bool waiting_connect_;
- // The pipe used for communication.
- int pipe_;
- // We use a thread for reading, so that we can simply block on reading and
- // post the received data back to the main thread to be properly interleaved
- // with other tasks in the MessagePump.
- //
- // imc_recvmsg supports non-blocking reads, but there's no easy way to be
- // informed when a write or read can be done without blocking (this is handled
- // by libevent in Posix).
- std::unique_ptr<ReaderThreadRunner> reader_thread_runner_;
- std::unique_ptr<base::DelegateSimpleThread> reader_thread_;
- // IPC::ChannelReader expects to be able to call ReadData on us to
- // synchronously read data waiting in the pipe's buffer without blocking.
- // Since we can't do that (see 1 and 2 above), the reader thread does blocking
- // reads and posts the data over to the main thread in MessageContents. Each
- // MessageContents object is the result of one call to "imc_recvmsg".
- // DidRecvMsg breaks the MessageContents out in to the data and the file
- // descriptors, and puts them on these two queues.
- // TODO(dmichael): There's probably a more efficient way to emulate this with
- // a circular buffer or something, so we don't have to do so
- // many heap allocations. But it maybe isn't worth
- // the trouble given that we probably want to implement 1 and
- // 2 above in NaCl eventually.
- // When ReadData is called, it pulls the bytes out of this queue in order.
- base::circular_deque<std::unique_ptr<std::vector<char>>> read_queue_;
- // Queue of file descriptor attachments extracted from imc_recvmsg messages.
- std::vector<scoped_refptr<MessageAttachment>> input_attachments_;
- // This queue is used when a message is sent prior to Connect having been
- // called. Normally after we're connected, the queue is empty.
- base::circular_deque<std::unique_ptr<Message>> output_queue_;
- base::WeakPtrFactory<ChannelNacl> weak_ptr_factory_;
- };
- } // namespace IPC
- #endif // IPC_IPC_CHANNEL_NACL_H_
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