Add a simple prototype "terminal" example.

sky/examples/terminal/terminal_file_impl.dart

Index: sky/examples/terminal/terminal_file_impl.dart
diff --git a/sky/examples/terminal/terminal_file_impl.dart b/sky/examples/terminal/terminal_file_impl.dart
new file mode 100644
index 0000000000000000000000000000000000000000..34b48c84fc3c79be71da1f006bb1a1c04e1ce379
--- /dev/null
+++ b/sky/examples/terminal/terminal_file_impl.dart
@@ -0,0 +1,124 @@
+// Copyright 2015 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.
+
+import 'dart:async';
+import 'dart:core';
+import 'mojo:core';
+import 'package:services/files/file.mojom.dart' as files;
+import 'package:services/files/types.mojom.dart' as files;
+
+import 'terminal_display.dart';
+
+// This implements a |mojo.files.File| that acts like a (pseudo)terminal. Bytes
+// written to the |File| will be read by this implementation and passed on to
+// the (Dart) |TerminalDisplay| (using |putChar()|). A read from the |File| will
+// be completed if/when |TerminalDisplay| makes a byte available (via
+// |getChar()|).
+// TODO(vtl): This implementation is very incomplete.
+class TerminalFileImpl implements files.File {
+  final files.FileStub stub;
+  final TerminalDisplay _display;
+
+  TerminalFileImpl(this._display) : stub = new files.FileStub.unbound() {
+    stub.impl = this;
+  }
+
+  // |files.File| implementation:
+
+  @override
+  Future close(Function responseFactory) async {
+    // TODO(vtl): We should probably do more than just say OK.
+    return responseFactory(files.Error_OK);
+  }
+
+  @override
+  Future read(int numBytesToRead, int offset, int whence,
+      Function responseFactory) async {
+    if (numBytesToRead < 0) {
+      return responseFactory(files.Error_INVALID_ARGUMENT, null);
+    }
+
+    // TODO(vtl): Error if |offset|/|whence| not appropriate.
+
+    if (numBytesToRead == 0) {
+      return responseFactory(files.Error_OK, []);
+    }
+
+    return responseFactory(files.Error_OK, [await _display.getChar()]);
+  }
+
+  @override
+  Future write(List<int> bytesToWrite, int offset, int whence,
+      Function responseFactory) async {
+    // TODO(vtl): Error if |offset|/|whence| not appropriate.
+
+    for (var c in bytesToWrite) {
+      _display.putChar(c);
+    }
+    return responseFactory(files.Error_OK, bytesToWrite.length);
+  }
+
+  @override
+  Future readToStream(MojoDataPipeProducer source, int offset, int whence,
+      int numBytesToRead, Function responseFactory) async {
+    // TODO(vtl)
+    return responseFactory(files.Error_UNIMPLEMENTED);
+  }
+
+  @override
+  Future writeFromStream(MojoDataPipeConsumer sink, int offset, int whence,
+      Function responseFactory) async {
+    // TODO(vtl)
+    return responseFactory(files.Error_UNIMPLEMENTED);
+  }
+
+  @override
+  Future tell(Function responseFactory) async {
+    // TODO(vtl)
+    return responseFactory(files.Error_UNIMPLEMENTED, 0);
+  }
+
+  @override
+  Future seek(int offset, int whence, Function responseFactory) async {
+    // TODO(vtl)
+    return responseFactory(files.Error_UNIMPLEMENTED, 0);
+  }
+
+  @override
+  Future stat(Function responseFactory) async {
+    // TODO(vtl)
+    return responseFactory(files.Error_UNIMPLEMENTED, null);
+  }
+
+  @override
+  Future truncate(int size, Function responseFactory) async {
+    // TODO(vtl)
+    return responseFactory(files.Error_UNIMPLEMENTED);
+  }
+
+  @override
+  Future touch(files.TimespecOrNow atime, files.TimespecOrNow mtime,
+      Function responseFactory) async {
+    // TODO(vtl)
+    return responseFactory(files.Error_UNIMPLEMENTED);
+  }
+
+  @override
+  Future dup(Object file, Function responseFactory) async {
+    // TODO(vtl)
+    return responseFactory(files.Error_UNIMPLEMENTED);
+  }
+
+  @override
+  Future reopen(Object file, int openFlags, Function responseFactory) async {
+    // TODO(vtl)
+    return responseFactory(files.Error_UNIMPLEMENTED);
+  }
+
+  @override
+  Future asBuffer(Function responseFactory) async {
+    // TODO(vtl)
+    return responseFactory(files.Error_UNIMPLEMENTED, null);
+  }
+}