Allow data pipe producer/consumer handles to be transferred during two-phase operations.

mojo/public/c/system/message_pipe.h

 // Copyright 2014 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.
 
 // This file contains types/constants and functions specific to message pipes.
 //
 // Note: This header should be compilable as C.
 
 #ifndef MOJO_PUBLIC_C_SYSTEM_MESSAGE_PIPE_H_
 #define MOJO_PUBLIC_C_SYSTEM_MESSAGE_PIPE_H_
@@ skipping 71 matching lines @@
 
 // |MojoWriteMessage()|: Writes a message to the message pipe endpoint given by
 // |message_pipe_handle| (which must have the |MOJO_HANDLE_RIGHT_WRITE| right),
 // with message data specified by |bytes| of size |num_bytes| and attached
 // handles specified by |handles| of count |num_handles|, and options specified
 // by |flags|. If there is no message data, |bytes| may be null, in which case
 // |num_bytes| must be zero. If there are no attached handles, |handles| may be
 // null, in which case |num_handles| must be zero.
 //
 // If handles are attached, on success the handles will no longer be valid (the
-// receiver will receive equivalent, but logically different, handles). Handles
-// to be sent should not be in simultaneous use (e.g., on another thread). On
-// failure, any handles to be attached will remain valid.
+// receiver will receive equivalent, but logically different, handles) and any
+// ongoing two-phase operations (e.g., for data pipes) on them will be aborted.
+// Handles to be sent should not be in simultaneous use (e.g., on another
+// thread). On failure, any handles to be attached will remain valid (and
+// two-phase operations will not be aborted).
 //
 // Returns:
 //   |MOJO_RESULT_OK| on success (i.e., the message was enqueued).
 //   |MOJO_RESULT_INVALID_ARGUMENT| if some argument was invalid (e.g., if
 //       |message_pipe_handle| is not a valid handle, or some of the
 //       requirements above are not satisfied).
 //   |MOJO_RESULT_PERMISSION_DENIED| if |message_pipe_handle| does not have the
 //       |MOJO_HANDLE_RIGHT_WRITE| right or if one of the handles to be sent
 //       does not have the |MOJO_HANDLE_RIGHT_TRANSFER| right.
 //   |MOJO_RESULT_RESOURCE_EXHAUSTED| if some system limit has been reached, or
@@ skipping 68 matching lines @@
     MojoHandle message_pipe_handle,       // In.
     void* MOJO_RESTRICT bytes,            // Optional out.
     uint32_t* MOJO_RESTRICT num_bytes,    // Optional in/out.
     MojoHandle* MOJO_RESTRICT handles,    // Optional out.
     uint32_t* MOJO_RESTRICT num_handles,  // Optional in/out.
     MojoReadMessageFlags flags);          // In.
 
 MOJO_END_EXTERN_C
 
 #endif  // MOJO_PUBLIC_C_SYSTEM_MESSAGE_PIPE_H_