Mojo: DataPipe: Test "all or nothing" mode.

mojo/system/local_data_pipe.cc

 // Copyright 2013 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.
 
 // TODO(vtl): I currently potentially overflow in doing index calculations.
 // E.g., |start_index_| and |current_num_bytes_| fit into a |uint32_t|, but
 // their sum may not. This is bad and poses a security risk. (We're currently
 // saved by the limit on capacity -- the maximum size of the buffer, checked in
 // |DataPipe::ValidateOptions()|, is currently sufficiently small.
 
@@ skipping 252 matching lines @@
 }
 
 MojoResult LocalDataPipe::ConsumerBeginReadDataImplNoLock(
     const void** buffer,
     uint32_t* buffer_num_bytes,
     bool all_or_none) {
   size_t max_num_bytes_to_read = GetMaxNumBytesToReadNoLock();
   if (all_or_none && *buffer_num_bytes > max_num_bytes_to_read) {
     // Don't return "should wait" since you can't wait for a specified amount of
     // data.
-    return MOJO_RESULT_OUT_OF_RANGE;
+    return producer_open_no_lock() ? MOJO_RESULT_OUT_OF_RANGE :
+                                     MOJO_RESULT_FAILED_PRECONDITION;
   }
 
   // Don't go into a two-phase read if there's no data.
   if (max_num_bytes_to_read == 0) {
     return producer_open_no_lock() ? MOJO_RESULT_SHOULD_WAIT :
                                      MOJO_RESULT_FAILED_PRECONDITION;
   }
 
   *buffer = buffer_.get() + start_index_;
   *buffer_num_bytes = static_cast<uint32_t>(max_num_bytes_to_read);
@@ skipping 70 matching lines @@
 }
 
 size_t LocalDataPipe::GetMaxNumBytesToReadNoLock() {
   if (start_index_ + current_num_bytes_ > capacity_num_bytes())
     return capacity_num_bytes() - start_index_;
   return current_num_bytes_;
 }
 
 }  // namespace system
 }  // namespace mojo