EDK: Add implementation of data pipe producer write threshold stuff.

mojo/edk/system/data_pipe.h

 // 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.
 
 #ifndef MOJO_EDK_SYSTEM_DATA_PIPE_H_
 #define MOJO_EDK_SYSTEM_DATA_PIPE_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 87 matching lines @@
   // failure (in which case |*data_pipe| may or may not be set to null).
   static bool ConsumerDeserialize(Channel* channel,
                                   const void* source,
                                   size_t size,
                                   util::RefPtr<DataPipe>* data_pipe);
 
   // These are called by the producer dispatcher to implement its methods of
   // corresponding names.
   void ProducerCancelAllAwakables();
   void ProducerClose();
+  MojoResult ProducerSetOptions(uint32_t write_threshold_num_bytes);
+  void ProducerGetOptions(uint32_t* write_threshold_num_bytes);
   MojoResult ProducerWriteData(UserPointer<const void> elements,
                                UserPointer<uint32_t> num_bytes,
                                bool all_or_none);
   MojoResult ProducerBeginWriteData(UserPointer<void*> buffer,
                                     UserPointer<uint32_t> buffer_num_bytes);
   MojoResult ProducerEndWriteData(uint32_t num_bytes_written);
   HandleSignalsState ProducerGetHandleSignalsState();
   MojoResult ProducerAddAwakable(Awakable* awakable,
                                  MojoHandleSignals signals,
                                  uint32_t context,
@@ skipping 72 matching lines @@
 
   // Must be called under |mutex_|.
   bool producer_open_no_lock() const MOJO_SHARED_LOCKS_REQUIRED(mutex_) {
     mutex_.AssertHeld();
     return producer_open_;
   }
   bool consumer_open_no_lock() const MOJO_SHARED_LOCKS_REQUIRED(mutex_) {
     mutex_.AssertHeld();
     return consumer_open_;
   }
+  // Note that this returns the "real" write threshold (never zero).
+  size_t producer_write_threshold_num_bytes_no_lock() const
+      MOJO_SHARED_LOCKS_REQUIRED(mutex_) {
+    mutex_.AssertHeld();
+    return (producer_write_threshold_num_bytes_ > 0u)
+               ? producer_write_threshold_num_bytes_
+               : element_num_bytes_;
+  }
   // Note that this returns the "real" read threshold (never zero).
   size_t consumer_read_threshold_num_bytes_no_lock() const
       MOJO_SHARED_LOCKS_REQUIRED(mutex_) {
     mutex_.AssertHeld();
     return (consumer_read_threshold_num_bytes_ > 0u)
                ? consumer_read_threshold_num_bytes_
                : element_num_bytes_;
   }
   uint32_t producer_two_phase_max_num_bytes_written_no_lock() const
       MOJO_SHARED_LOCKS_REQUIRED(mutex_) {
@@ skipping 65 matching lines @@
   }
 
   const uint32_t element_num_bytes_;
   const uint32_t capacity_num_bytes_;
 
   mutable util::Mutex mutex_;
   // *Known* state of producer or consumer.
   bool producer_open_ MOJO_GUARDED_BY(mutex_);
   bool consumer_open_ MOJO_GUARDED_BY(mutex_);
   // This may be zero (in which case it "means" |element_num_bytes_|).
+  uint32_t producer_write_threshold_num_bytes_ MOJO_GUARDED_BY(mutex_);
+  // This may be zero (in which case it "means" |element_num_bytes_|).
   uint32_t consumer_read_threshold_num_bytes_ MOJO_GUARDED_BY(mutex_);
   // Non-null only if the producer or consumer, respectively, is local.
   std::unique_ptr<AwakableList> producer_awakable_list_ MOJO_GUARDED_BY(mutex_);
   std::unique_ptr<AwakableList> consumer_awakable_list_ MOJO_GUARDED_BY(mutex_);
   // These are nonzero if and only if a two-phase write/read is in progress.
   uint32_t producer_two_phase_max_num_bytes_written_ MOJO_GUARDED_BY(mutex_);
   uint32_t consumer_two_phase_max_num_bytes_read_ MOJO_GUARDED_BY(mutex_);
   std::unique_ptr<DataPipeImpl> impl_ MOJO_GUARDED_BY(mutex_);
 
   MOJO_DISALLOW_COPY_AND_ASSIGN(DataPipe);
 };
 
 }  // namespace system
 }  // namespace mojo
 
 #endif  // MOJO_EDK_SYSTEM_DATA_PIPE_H_