Dart: Avoid MojoResult and MojoHandleSignals constructors.

mojo/dart/packages/mojo/lib/src/message_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 MojoMessagePipeReadResult {
-  final MojoResult status;
+  final int status;
   final int bytesRead;
   final int handlesRead;
 
   MojoMessagePipeReadResult(this.status, this.bytesRead, this.handlesRead);
   MojoMessagePipeReadResult.fromList(List<int> resultList)
-      : this(new MojoResult(resultList[0]), resultList[1], resultList[2]);
+      : this(resultList[0], resultList[1], resultList[2]);
 
   String toString() {
     return "MojoMessagePipeReadResult("
-        "status: $status, bytesRead: $bytesRead, handlesRead: $handlesRead)";
+        "status: ${MojoResult.string(status)}, bytesRead: $bytesRead, "
+        "handlesRead: $handlesRead)";
   }
 }
 
 class MojoMessagePipeQueryAndReadState {
   static final List _result = new List(5);
 
   List<MojoHandle> _handles;
 
-  MojoResult get status => new MojoResult(_result[0]);
+  int get status => _result[0];
   ByteData get data => _result[1];
   List<MojoHandle> get handles => _handles;
   int get dataLength => _result[3];
   int get handlesLength => _result[4];
 
   MojoMessagePipeQueryAndReadState();
 
   void queryAndRead(int handle, int flags) {
     MojoMessagePipeNatives.MojoQueryAndReadMessage(handle, flags, _result);
 
     if (handlesLength == 0) {
       _handles = null;
     } else {
       _handles = new List(handlesLength);
       for (int i = 0; i < handlesLength; i++) {
         _handles[i] = new MojoHandle(_result[2][i]);
       }
     }
   }
 
   String toString() {
     return "MojoMessagePipeQueryAndReadState("
-        "status: $status, dataLength: $dataLength, "
+        "status: ${MojoResult.string(status)}, dataLength: $dataLength, "
         "handlesLength: $handlesLength)";
   }
 }
 
 class MojoMessagePipeEndpoint {
   static const int WRITE_FLAG_NONE = 0;
   static const int READ_FLAG_NONE = 0;
   static const int READ_FLAG_MAY_DISCARD = 1 << 0;
 
   static final _queryAndReadState = new MojoMessagePipeQueryAndReadState();
 
   MojoHandle handle;
-  MojoResult status;
+  int status;
 
   MojoMessagePipeEndpoint(this.handle);
 
-  MojoResult write(ByteData data,
+  bool get ok => status == MojoResult.kOk;
+
+  int write(ByteData data,
       [int numBytes = -1, List<MojoHandle> handles = null, int flags = 0]) {
     if (handle == null) {
-      status = MojoResult.INVALID_ARGUMENT;
+      status = MojoResult.kInvalidArgument;
       return status;
     }
 
     int dataLengthInBytes = (data == null) ? 0 : data.lengthInBytes;
 
     // If numBytes has the default value, use the full length of the data.
     int dataNumBytes = (numBytes == -1) ? dataLengthInBytes : numBytes;
     if (dataNumBytes > dataLengthInBytes) {
-      status = MojoResult.INVALID_ARGUMENT;
+      status = MojoResult.kInvalidArgument;
       return status;
     }
 
     // handles may be null, otherwise convert to ints.
     List<int> mojoHandles =
         (handles != null) ? handles.map((h) => h.h).toList() : null;
 
     // Do the call.
-    int result = MojoMessagePipeNatives.MojoWriteMessage(
+    status = MojoMessagePipeNatives.MojoWriteMessage(
         handle.h, data, dataNumBytes, mojoHandles, flags);
-
-    status = new MojoResult(result);
     return status;
   }
 
   MojoMessagePipeReadResult read(ByteData data,
       [int numBytes = -1, List<MojoHandle> handles = null, int flags = 0]) {
     if (handle == null) {
-      status = MojoResult.INVALID_ARGUMENT;
+      status = MojoResult.kInvalidArgument;
       return null;
     }
 
     // If numBytes has the default value, use the full length of the data.
     int dataNumBytes;
     if (data == null) {
       dataNumBytes = 0;
     } else {
       dataNumBytes = (numBytes == -1) ? data.lengthInBytes : numBytes;
       if (dataNumBytes > data.lengthInBytes) {
-        status = MojoResult.INVALID_ARGUMENT;
+        status = MojoResult.kInvalidArgument;
         return null;
       }
     }
 
     // handles may be null, otherwise make an int list for the handles.
     List<int> mojoHandles;
     if (handles == null) {
       mojoHandles = null;
     } else {
       mojoHandles = new List<int>(handles.length);
     }
 
     // Do the call.
     List result = MojoMessagePipeNatives.MojoReadMessage(
         handle.h, data, dataNumBytes, mojoHandles, flags);
 
     if (result == null) {
-      status = MojoResult.INVALID_ARGUMENT;
+      status = MojoResult.kInvalidArgument;
       return null;
     }
 
     assert((result is List) && (result.length == 3));
     var readResult = new MojoMessagePipeReadResult.fromList(result);
 
     // Copy out the handles that were read.
     if (handles != null) {
       for (var i = 0; i < readResult.handlesRead; i++) {
         handles[i] = new MojoHandle(mojoHandles[i]);
       }
     }
 
     status = readResult.status;
     return readResult;
   }
 
   MojoMessagePipeReadResult query() => read(null);
 
   bool setDescription(String description) =>
       MojoHandleNatives.setDescription(handle.h, description);
 
   /// Warning: The object returned by this function, and the buffers inside of
   /// it are only valid until the next call to this function by the same
   /// isolate.
   MojoMessagePipeQueryAndReadState queryAndRead([int flags = 0]) {
     if (handle == null) {
-      status = MojoResult.INVALID_ARGUMENT;
+      status = MojoResult.kInvalidArgument;
       return null;
     }
 
     _queryAndReadState.queryAndRead(handle.h, flags);
     status = _queryAndReadState.status;
     return _queryAndReadState;
   }
 
   void close() {
     handle.close();
     handle = null;
   }
 
-  String toString() =>
-      "MojoMessagePipeEndpoint(handle: $handle, status: $status)";
+  String toString() => "MojoMessagePipeEndpoint(handle: $handle, "
+      "status: ${MojoResult.string(status)})";
 }
 
 class MojoMessagePipe {
   static const int FLAG_NONE = 0;
 
   List<MojoMessagePipeEndpoint> endpoints;
-  MojoResult status;
+  int status;
 
-  MojoMessagePipe._() {
-    endpoints = null;
-    status = MojoResult.OK;
-  }
+  MojoMessagePipe._() : status = MojoResult.kOk;
 
   factory MojoMessagePipe([int flags = FLAG_NONE]) {
     List result = MojoMessagePipeNatives.MojoCreateMessagePipe(flags);
     if (result == null) {
       return null;
     }
     assert((result is List) && (result.length == 3));
 
     MojoHandle end1 = new MojoHandle(result[1]);
     MojoHandle end2 = new MojoHandle(result[2]);
     MojoMessagePipe pipe = new MojoMessagePipe._();
     pipe.endpoints = new List(2);
     pipe.endpoints[0] = new MojoMessagePipeEndpoint(end1);
     pipe.endpoints[1] = new MojoMessagePipeEndpoint(end2);
-    pipe.status = new MojoResult(result[0]);
+    pipe.status = result[0];
     return pipe;
   }
 }