Dart: Simplifies the handle watcher. Various cleanups and bugfixes.

mojo/public/dart/src/data_pipe.dart

 // 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.
 
 part of core;
 
 
 class _MojoDataPipeNatives {
   static List MojoCreateDataPipe(
       int element_bytes, int capacity_bytes, int flags)
@@ skipping 16 matching lines @@
 
   static int MojoEndReadData(int handle, int bytes_read)
       native "MojoDataPipe_EndReadData";
 }
 
 
 class MojoDataPipeProducer {
   static const int FLAG_NONE = 0;
   static const int FLAG_ALL_OR_NONE = 1 << 0;
 
-  RawMojoHandle handle;
+  MojoHandle handle;
   MojoResult status;
   final int element_bytes;
 
   MojoDataPipeProducer(this.handle,
                        this.status,
                        this.element_bytes);
 
   int write(ByteData data, [int num_bytes = -1, int flags = 0]) {
     if (handle == null) {
       status = MojoResult.INVALID_ARGUMENT;
@@ skipping 41 matching lines @@
     return status;
   }
 }
 
 
 class MojoDataPipeConsumer {
   static const int FLAG_NONE = 0;
   static const int FLAG_ALL_OR_NONE = 1 << 0;
   static const int FLAG_MAY_DISCARD = 1 << 1;
   static const int FLAG_QUERY = 1 << 2;
+  static const int FLAG_PEEK = 1 << 3;
 
-  RawMojoHandle handle;
+  MojoHandle handle;
   MojoResult status;
   final int element_bytes;
 
-  MojoDataPipeConsumer(this.handle,
-                       this.status,
-                       this.element_bytes);
+  MojoDataPipeConsumer(
+      this.handle, [this.status = MojoResult.OK, this.element_bytes = 1]);
 
   int read(ByteData data, [int num_bytes = -1, int flags = 0]) {
     if (handle == null) {
       status = MojoResult.INVALID_ARGUMENT;
       return status;
     }
 
     int data_num_bytes = (num_bytes == -1) ? data.lengthInBytes : num_bytes;
     List result = _MojoDataPipeNatives.MojoReadData(
         handle.h, data, data_num_bytes, flags);
     if (result == null) {
       status = MojoResult.INVALID_ARGUMENT;
       return status;
     }
     assert((result is List) && (result.length == 2));
     status = new MojoResult(result[0]);
     return result[1];
   }
 
-  ByteData beginRead(int buffer_bytes, [int flags = 0]) {
+  ByteData beginRead([int buffer_bytes = 0, int flags = 0]) {
     if (handle == null) {
       status = MojoResult.INVALID_ARGUMENT;
       return null;
     }
 
     List result = _MojoDataPipeNatives.MojoBeginReadData(
         handle.h, buffer_bytes, flags);
     if (result == null) {
       status = MojoResult.INVALID_ARGUMENT;
       return null;
     }
 
     assert((result is List) && (result.length == 2));
     status = new MojoResult(result[0]);
     return result[1];
   }
 
   MojoResult endRead(int bytes_read) {
     if (handle == null) {
       status = MojoResult.INVALID_ARGUMENT;
       return status;
     }
     int result = _MojoDataPipeNatives.MojoEndReadData(handle.h, bytes_read);
     status = new MojoResult(result);
     return status;
   }
+
+  int query() => read(null, 0, FLAG_QUERY);
 }
 
 
 class MojoDataPipe {
   static const int FLAG_NONE = 0;
   static const int FLAG_MAY_DISCARD = 1 << 0;
   static const int DEFAULT_ELEMENT_SIZE = 1;
   static const int DEFAULT_CAPACITY = 0;
 
   MojoDataPipeProducer producer;
   MojoDataPipeConsumer consumer;
   MojoResult status;
 
   MojoDataPipe._internal() {
     producer = null;
     consumer = null;
     status = MojoResult.OK;
   }
 
   factory MojoDataPipe([int element_bytes = DEFAULT_ELEMENT_SIZE,
                         int capacity_bytes = DEFAULT_CAPACITY,
                         int flags = FLAG_NONE]) {
     List result = _MojoDataPipeNatives.MojoCreateDataPipe(
         element_bytes, capacity_bytes, flags);
     if (result == null) {
       return null;
     }
     assert((result is List) && (result.length == 3));
-    RawMojoHandle producer_handle = new RawMojoHandle(result[1]);
-    RawMojoHandle consumer_handle = new RawMojoHandle(result[2]);
+    MojoHandle producer_handle = new MojoHandle(result[1]);
+    MojoHandle consumer_handle = new MojoHandle(result[2]);
     MojoDataPipe pipe = new MojoDataPipe._internal();
     pipe.producer = new MojoDataPipeProducer(
         producer_handle, new MojoResult(result[0]), element_bytes);
     pipe.consumer = new MojoDataPipeConsumer(
         consumer_handle, new MojoResult(result[0]), element_bytes);
     pipe.status = new MojoResult(result[0]);
     return pipe;
   }
 }