SyncSocket Transit Descriptor - refactoring

base/sync_socket.h

 // 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 "base/basictypes.h"
 #if defined(OS_WIN)
 #include <windows.h>
 #endif
 #include <sys/types.h>
 
 #include "base/base_export.h"
 #include "base/compiler_specific.h"
+#include "base/process/process_handle.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/time/time.h"
 
+#if defined(OS_POSIX)
+#include "base/file_descriptor_posix.h"
+#endif
+
 namespace base {
 
 class BASE_EXPORT SyncSocket {
  public:
 #if defined(OS_WIN)
   typedef HANDLE Handle;
+  typedef Handle TransitDescriptor;
 #else
   typedef int Handle;
+  typedef FileDescriptor TransitDescriptor;
 #endif
   static const Handle kInvalidHandle;
 
   SyncSocket();
 
   // Creates a SyncSocket from a Handle.  Used in transport.
   explicit SyncSocket(Handle handle) : handle_(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);
 
+  // Returns |Handle| wrapped in a |TransitDescriptor|.
+  static Handle UnwrapHandle(const TransitDescriptor& descriptor);
+
+  // Prepares a |TransitDescriptor| which wraps |Handle| used for transit.
+  // This is used to prepare the underlying shared resource before passing back
+  // the handle to be used by the peer process.
+  bool PrepareTransitDescriptor(ProcessHandle peer_process_handle,
+                                TransitDescriptor* descriptor);
+
   // Closes the SyncSocket.  Returns true on success, false on failure.
   virtual 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.
   virtual size_t Send(const void* buffer, size_t length);
@@ skipping 77 matching lines @@
 
 #if defined(OS_WIN) && !defined(COMPONENT_BUILD)
 // TODO(cpu): remove this once chrome is split in two dlls.
 __declspec(selectany)
     const SyncSocket::Handle SyncSocket::kInvalidHandle = INVALID_HANDLE_VALUE;
 #endif
 
 }  // namespace base
 
 #endif  // BASE_SYNC_SOCKET_H_