Initial work on Dart bindings for Mojo.

mojo/public/dart/system/lib/src/buffer.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 _MojoSharedBufferNatives {
+  static List Create(int num_bytes, int flags)
+      native "MojoSharedBuffer_Create";
+
+  static List Duplicate(int buffer_handle, int flags)
+      native "MojoSharedBuffer_Duplicate";
+
+  static List Map(int buffer_handle, int offset, int num_bytes, int flags)
+      native "MojoSharedBuffer_Map";
+
+  static int Unmap(ByteData buffer)
+      native "MojoSharedBuffer_Unmap";
+}
+
+
+class MojoSharedBuffer {
+  static final int CREATE_FLAG_NONE = 0;
+  static final int DUPLICATE_FLAG_NONE = 0;
+  static final int MAP_FLAG_NONE = 0;
+
+  RawMojoHandle handle;
+  int status;
+  ByteData mapping;
+
+  MojoSharedBuffer._internal() {
+    handle = null;
+    status = MojoResult.OK;
+    mapping = null;
+  }
+
+  factory MojoSharedBuffer.create(int num_bytes, [int flags = 0]) {
+    List result = _MojoSharedBufferNatives.Create(num_bytes, flags);
+    if (result == null) {
+      return null;
+    }
+    assert((result is List) && (result.length == 2));
+    if (!MojoResult.isOk(result[0])) {
+      return null;
+    }
+
+    MojoSharedBuffer buf = new MojoSharedBuffer._internal();
+    buf.status = result[0];
+    buf.handle = new RawMojoHandle(result[1]);
+    buf.mapping = null;
+    return buf;
+  }
+
+  factory MojoSharedBuffer.duplicate(
+      MojoSharedBuffer msb, [int flags = 0]) {
+    List result = _MojoSharedBufferNatives.Duplicate(msb.handle.h, flags);
+    if (result == null) {
+      return null;
+    }
+    assert((result is List) && (result.length == 2));
+    if (!MojoResult.isOk(result[0])) {
+      return null;
+    }
+
+    MojoSharedBuffer dupe = new MojoSharedBuffer._internal();
+    dupe.status = result[0];
+    dupe.handle = new RawMojoHandle(result[1]);
+    dupe.mapping = msb.mapping;
+    return dupe;
+  }
+
+  int close() {
+    int r = handle.close();
+    status = r;
+    mapping = null;
+    return r;
+  }
+
+  int map(int offset, int num_bytes, [int flags = 0]) {
+    List result = _MojoSharedBufferNatives.Map(
+        handle.h, offset, num_bytes, flags);
+    if (result == null) {
+      status = MojoResult.INVALID_ARGUMENT;
+      return status;
+    }
+    assert((result is List) && (result.length == 2));
+    status = result[0];
+    mapping = result[1];
+    return status;
+  }
+
+  int unmap() {
+    int r = _MojoSharedBufferNatives.Unmap(mapping);
+    status = r;
+    mapping = null;
+    return r;
+  }
+}