commit 833e71a438e83bd654b9e71af1676a2be93459fc
author Viet-Trung Luu <viettrungluu@chromium.org> Tue Apr 05 14:17:48 2016 -0700
committer Viet-Trung Luu <viettrungluu@chromium.org> Tue Apr 05 14:17:48 2016 -0700
tree a0aba3d8b456dd1f5b6b3d229c327983bbd4e7d7
parent 15c6fa026b23a71407f4597132e60a5a73f8dd25

Let MojoSetDataPipeConsumerOptions() take null options.

The header defining it says that doing so means reset back to the
default options. I forgot about this when implementing it. Oops. :-/

R=vardhan@google.com
BUG=#442

Review URL: https://codereview.chromium.org/1865663002 .

mojo/edk/system/core_unittest.cc

diff --git a/mojo/edk/system/core_unittest.cc b/mojo/edk/system/core_unittest.cc
index 0fdd5ac..bb8967a 100644
--- a/mojo/edk/system/core_unittest.cc
+++ b/mojo/edk/system/core_unittest.cc
@@ -1250,11 +1250,9 @@
   EXPECT_EQ(kCoptsSize, copts.struct_size);
   EXPECT_EQ(16u, copts.read_threshold_num_bytes);
 
-  // Default read threshold.
-  copts.struct_size = kCoptsSize;
-  copts.read_threshold_num_bytes = 0;
+  // Can also set to default by passing null.
   EXPECT_EQ(MOJO_RESULT_OK,
-            core()->SetDataPipeConsumerOptions(ch, MakeUserPointer(&copts)));
+            core()->SetDataPipeConsumerOptions(ch, NullUserPointer()));
   copts = MojoDataPipeConsumerOptions();
   EXPECT_EQ(MOJO_RESULT_OK, core()->GetDataPipeConsumerOptions(
                                 ch, MakeUserPointer(&copts), kCoptsSize));

mojo/edk/system/data_pipe_consumer_dispatcher.cc

diff --git a/mojo/edk/system/data_pipe_consumer_dispatcher.cc b/mojo/edk/system/data_pipe_consumer_dispatcher.cc
index 5d10c77..2b3aed0 100644
--- a/mojo/edk/system/data_pipe_consumer_dispatcher.cc
+++ b/mojo/edk/system/data_pipe_consumer_dispatcher.cc
@@ -79,16 +79,21 @@
     UserPointer<const MojoDataPipeConsumerOptions> options) {
   mutex().AssertHeld();
 
-  UserOptionsReader<MojoDataPipeConsumerOptions> reader(options);
-  if (!reader.is_valid())
-    return MOJO_RESULT_INVALID_ARGUMENT;
+  // The default of 0 means 1 element (however big that is).
+  uint32_t read_threshold_num_bytes = 0;
+  if (!options.IsNull()) {
+    UserOptionsReader<MojoDataPipeConsumerOptions> reader(options);
+    if (!reader.is_valid())
+      return MOJO_RESULT_INVALID_ARGUMENT;
 
-  if (!OPTIONS_STRUCT_HAS_MEMBER(MojoDataPipeConsumerOptions,
-                                 read_threshold_num_bytes, reader))
-    return MOJO_RESULT_OK;
+    if (!OPTIONS_STRUCT_HAS_MEMBER(MojoDataPipeConsumerOptions,
+                                   read_threshold_num_bytes, reader))
+      return MOJO_RESULT_OK;
 
-  return data_pipe_->ConsumerSetOptions(
-      reader.options().read_threshold_num_bytes);
+    read_threshold_num_bytes = reader.options().read_threshold_num_bytes;
+  }
+
+  return data_pipe_->ConsumerSetOptions(read_threshold_num_bytes);
 }
 
 MojoResult DataPipeConsumerDispatcher::GetDataPipeConsumerOptionsImplNoLock(