Make Python not support "all or none" for two-phase data pipe read/write.

mojo/public/python/mojo_system.pyx

 # 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.
 
 # distutils language = c++
 
 cimport c_core
 cimport c_export  # needed so the init function gets exported
 cimport c_thunks
 
@@ skipping 473 matching lines @@
     cdef uint32_t input_buffer_length = buffer_as_buffer.len
     cdef c_core.MojoResult res = c_core.MojoWriteData(self._mojo_handle,
                                                       buffer_as_buffer.buf,
                                                       &input_buffer_length,
                                                       flags)
     if res == c_core.MOJO_RESULT_OK:
       return (res, input_buffer_length)
     return (res, None)
 
   def BeginWriteData(self,
-                       min_size=None,
-                       flags=WRITE_DATA_FLAG_NONE):
+                     flags=WRITE_DATA_FLAG_NONE):
     """
     Begins a two-phase write to the data pipe producer.
 
     This method can only be used on a producer handle obtained from
     |DataPipe()|.
 
     This method returns a tuple (code, two_phase_buffer).
     - If code is RESULT_OK, two_phase_buffer is a writable
       DataPipeTwoPhaseBuffer
     - Otherwise, two_phase_buffer is None.
 
     See mojo/public/c/system/data_pipe.h
     """
     cdef void* out_buffer
     cdef uint32_t out_size = 0
-    if min_size:
-      flags |= c_core.MOJO_WRITE_DATA_FLAG_ALL_OR_NONE
-      out_size = min_size
     cdef c_core.MojoResult res = c_core.MojoBeginWriteData(self._mojo_handle,
                                                            &out_buffer,
                                                            &out_size,
                                                            flags)
     if res != c_core.MOJO_RESULT_OK:
       return (res, None)
     cdef _NativeMemoryView view_buffer = _NativeMemoryView(self)
     view_buffer.Wrap(out_buffer, out_size, read_only=False)
     return (res, DataPipeTwoPhaseBuffer(self, memoryview(view_buffer), False))
 
@@ skipping 34 matching lines @@
     See mojo/public/c/system/data_pipe.h
     """
     cdef uint32_t num_bytes = 0
     cdef c_core.MojoResult res = c_core.MojoReadData(
         self._mojo_handle,
         NULL,
         &num_bytes,
         flags|c_core.MOJO_READ_DATA_FLAG_QUERY)
     return (res, num_bytes)
 
-  def BeginReadData(self, min_size=None, flags=READ_DATA_FLAG_NONE):
+  def BeginReadData(self, flags=READ_DATA_FLAG_NONE):
     """
     Begins a two-phase read to the data pipe consumer.
 
     This method can only be used on a consumer handle obtained from
     |DataPipe()|.
 
     This method returns a tuple (code, two_phase_buffer).
     - If code is RESULT_OK, two_phase_buffer is a readable
       DataPipeTwoPhaseBuffer
     - Otherwise, two_phase_buffer is None.
 
     See mojo/public/c/system/data_pipe.h
     """
     cdef const void* out_buffer
     cdef uint32_t out_size = 0
-    if min_size:
-      flags |= c_core.MOJO_READ_DATA_FLAG_ALL_OR_NONE
-      out_size = min_size
     cdef c_core.MojoResult res = c_core.MojoBeginReadData(self._mojo_handle,
                                                           &out_buffer,
                                                           &out_size,
                                                           flags)
     if res != c_core.MOJO_RESULT_OK:
       return (res, None)
     cdef _NativeMemoryView view_buffer = _NativeMemoryView(self)
     view_buffer.Wrap(out_buffer, out_size, read_only=True)
     return (res, DataPipeTwoPhaseBuffer(self, memoryview(view_buffer), True))
 
@@ skipping 197 matching lines @@
     return self.__run_loop.PostDelayedTask(runnable, delay)
 
   @staticmethod
   def Current():
     if hasattr(_RUN_LOOPS, 'loop'):
       return _RUN_LOOPS.loop()
     return None
 
 
 _ASYNC_WAITER = mojo_system_impl.AsyncWaiter()