EDK: Add implementation of data pipe consumer read threshold stuff.

mojo/edk/system/data_pipe_consumer_dispatcher.cc

Index: 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 a32e05e1e3c383d55d6e8a88ade7d5205d6b81f3..5d10c77264990f2eaa5fe5ac1ad4275091153ac4 100644
--- a/mojo/edk/system/data_pipe_consumer_dispatcher.cc
+++ b/mojo/edk/system/data_pipe_consumer_dispatcher.cc
@@ -9,6 +9,7 @@
 #include "base/logging.h"
 #include "mojo/edk/system/data_pipe.h"
 #include "mojo/edk/system/memory.h"
+#include "mojo/edk/system/options_validation.h"
 
 using mojo::platform::ScopedPlatformHandle;
 using mojo::util::MutexLocker;
@@ -74,6 +75,46 @@ DataPipeConsumerDispatcher::CreateEquivalentDispatcherAndCloseImplNoLock() {
   return dispatcher;
 }
 
+MojoResult DataPipeConsumerDispatcher::SetDataPipeConsumerOptionsImplNoLock(
+    UserPointer<const MojoDataPipeConsumerOptions> options) {
+  mutex().AssertHeld();
+
+  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;
+
+  return data_pipe_->ConsumerSetOptions(
+      reader.options().read_threshold_num_bytes);
+}
+
+MojoResult DataPipeConsumerDispatcher::GetDataPipeConsumerOptionsImplNoLock(
+    UserPointer<MojoDataPipeConsumerOptions> options,
+    uint32_t options_num_bytes) {
+  mutex().AssertHeld();
+
+  // Note: If/when |MojoDataPipeConsumerOptions| is extended beyond its initial
+  // definition, more work will be necessary. (See the definition of
+  // |MojoGetDataPipeConsumerOptions()| in mojo/public/c/system/data_pipe.h.)
+  static_assert(sizeof(MojoDataPipeConsumerOptions) == 8u,
+                "MojoDataPipeConsumerOptions has been extended!");
+
+  if (options_num_bytes < sizeof(MojoDataPipeConsumerOptions))
+    return MOJO_RESULT_INVALID_ARGUMENT;
+
+  uint32_t read_threshold_num_bytes = 0;
+  data_pipe_->ConsumerGetOptions(&read_threshold_num_bytes);
+  MojoDataPipeConsumerOptions model_options = {
+      sizeof(MojoDataPipeConsumerOptions),  // |struct_size|.
+      read_threshold_num_bytes,             // |read_threshold_num_bytes|.
+  };
+  options.Put(model_options);
+  return MOJO_RESULT_OK;
+}
+
 MojoResult DataPipeConsumerDispatcher::ReadDataImplNoLock(
     UserPointer<void> elements,
     UserPointer<uint32_t> num_bytes,