This adds the first version of SyncSocket to base, along with a trivial unittest.

SyncSocket provides a blocking send/receive that can be used for synchronization.

Review URL: http://codereview.chromium.org/418004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@32927 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 66 insertions, 0 deletions

diff --git a/base/sync_socket.h b/base/sync_socket.h
new file mode 100644
index 0000000..ad181ff
--- /dev/null
+++ b/base/sync_socket.h
@@ -0,0 +1,66 @@
+// Copyright (c) 2009 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 they are blocking, they can be used to perform
+// rudimentary cross-process synchronization with low latency.
+
+#include "base/basictypes.h"
+#if defined(OS_WIN)
+#include <windows.h>
+#endif
+#include <sys/types.h>
+
+namespace base {
+
+class SyncSocket {
+ public:
+#if defined(OS_WIN)
+  typedef HANDLE Handle;
+#else
+  typedef int Handle;
+#endif
+
+  // Creates a SyncSocket from a Handle.  Used in transport.
+  explicit SyncSocket(Handle handle) : handle_(handle) { }
+  ~SyncSocket() { Close(); }
+
+  // Creates an unnamed pair of connected sockets.
+  // pair is a pointer to an array of two SyncSockets in which connected socket
+  // descriptors are returned.  Returns true on success, false on failure.
+  static bool CreatePair(SyncSocket* pair[2]);
+
+  // Closes the SyncSocket.  Returns true on success, false on failure.
+  bool 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.
+  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.
+  size_t Receive(void* buffer, size_t length);
+
+  // Extracts the contained handle.  Used for transferring between
+  // processes.
+  Handle handle() const { return handle_; }
+
+ private:
+  Handle handle_;
+
+  DISALLOW_COPY_AND_ASSIGN(SyncSocket);
+};
+
+}  // namespace base
+
+#endif  // BASE_SYNC_SOCKET_H_