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TMessagesProj/jni/voip/webrtc/base/sync_socket.h

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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 BASE_SYNC_SOCKET_H_
+#define BASE_SYNC_SOCKET_H_
+
+// A socket abstraction used for sending and receiving plain
+// data.  Because the receiving is blocking, they can be used to perform
+// rudimentary cross-process synchronization with low latency.
+
+#include <stddef.h>
+
+#include "base/base_export.h"
+#include "base/compiler_specific.h"
+#include "base/files/platform_file.h"
+#include "base/macros.h"
+#include "base/synchronization/waitable_event.h"
+#include "base/time/time.h"
+#include "build/build_config.h"
+
+#if defined(OS_WIN)
+#include <windows.h>
+#endif
+#include <sys/types.h>
+
+#if defined(OS_POSIX) || defined(OS_FUCHSIA)
+#include "base/file_descriptor_posix.h"
+#endif
+
+namespace base {
+
+class BASE_EXPORT SyncSocket {
+ public:
+  using Handle = PlatformFile;
+  using ScopedHandle = ScopedPlatformFile;
+  static const Handle kInvalidHandle;
+
+  SyncSocket();
+
+  // Creates a SyncSocket from a Handle.
+  explicit SyncSocket(Handle handle);
+  explicit SyncSocket(ScopedHandle handle);
+  virtual ~SyncSocket();
+
+  // Initializes and connects a pair of sockets.
+  // |socket_a| and |socket_b| must not hold a valid handle.  Upon successful
+  // return, the sockets will both be valid and connected.
+  static bool CreatePair(SyncSocket* socket_a, SyncSocket* socket_b);
+
+  // Closes the SyncSocket.
+  virtual void Close();
+
+  // Sends the message to the remote peer of the SyncSocket.
+  // Note it is not safe to send messages from the same socket handle by
+  // multiple threads simultaneously.
+  // buffer is a pointer to the data to send.
+  // length is the length of the data to send (must be non-zero).
+  // Returns the number of bytes sent, or 0 upon failure.
+  virtual size_t Send(const void* buffer, size_t length);
+
+  // Receives a message from an SyncSocket.
+  // buffer is a pointer to the buffer to receive data.
+  // length is the number of bytes of data to receive (must be non-zero).
+  // Returns the number of bytes received, or 0 upon failure.
+  virtual size_t Receive(void* buffer, size_t length);
+
+  // Same as Receive() but only blocks for data until |timeout| has elapsed or
+  // |buffer| |length| is exhausted.  Currently only timeouts less than one
+  // second are allowed.  Return the amount of data read.
+  virtual size_t ReceiveWithTimeout(void* buffer,
+                                    size_t length,
+                                    TimeDelta timeout);
+
+  // Returns the number of bytes available. If non-zero, Receive() will not
+  // not block when called.
+  virtual size_t Peek();
+
+  // Returns true if the Handle is valid, and false if it is not.
+  bool IsValid() const;
+
+  // Extracts the contained handle.  Used for transferring between
+  // processes.
+  Handle handle() const;
+
+  // Extracts and takes ownership of the contained handle.
+  Handle Release();
+  ScopedHandle Take();
+
+ protected:
+  ScopedHandle handle_;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(SyncSocket);
+};
+
+// Derives from SyncSocket and adds support for shutting down the socket from
+// another thread while a blocking Receive or Send is being done from the
+// thread that owns the socket.
+class BASE_EXPORT CancelableSyncSocket : public SyncSocket {
+ public:
+  CancelableSyncSocket();
+  explicit CancelableSyncSocket(Handle handle);
+  explicit CancelableSyncSocket(ScopedHandle handle);
+  ~CancelableSyncSocket() override = default;
+
+  // Initializes a pair of cancelable sockets.  See documentation for
+  // SyncSocket::CreatePair for more details.
+  static bool CreatePair(CancelableSyncSocket* socket_a,
+                         CancelableSyncSocket* socket_b);
+
+  // A way to shut down a socket even if another thread is currently performing
+  // a blocking Receive or Send.
+  bool Shutdown();
+
+#if defined(OS_WIN)
+  // Since the Linux and Mac implementations actually use a socket, shutting
+  // them down from another thread is pretty simple - we can just call
+  // shutdown().  However, the Windows implementation relies on named pipes
+  // and there isn't a way to cancel a blocking synchronous Read that is
+  // supported on <Vista. So, for Windows only, we override these
+  // SyncSocket methods in order to support shutting down the 'socket'.
+  void Close() override;
+  size_t Receive(void* buffer, size_t length) override;
+  size_t ReceiveWithTimeout(void* buffer,
+                            size_t length,
+                            TimeDelta timeout) override;
+#endif
+
+  // Send() is overridden to catch cases where the remote end is not responding
+  // and we fill the local socket buffer. When the buffer is full, this
+  // implementation of Send() will not block indefinitely as
+  // SyncSocket::Send will, but instead return 0, as no bytes could be sent.
+  // Note that the socket will not be closed in this case.
+  size_t Send(const void* buffer, size_t length) override;
+
+ private:
+#if defined(OS_WIN)
+  WaitableEvent shutdown_event_;
+  WaitableEvent file_operation_;
+#endif
+  DISALLOW_COPY_AND_ASSIGN(CancelableSyncSocket);
+};
+
+}  // namespace base
+
+#endif  // BASE_SYNC_SOCKET_H_