Add echo and line modes to Stdin.

runtime/bin/stdin_macos.cc

Index: runtime/bin/stdin_macos.cc
diff --git a/runtime/bin/stdin_macos.cc b/runtime/bin/stdin_macos.cc
new file mode 100644
index 0000000000000000000000000000000000000000..cb37a8b78ce12485360e697a5668435fb9591827
--- /dev/null
+++ b/runtime/bin/stdin_macos.cc
@@ -0,0 +1,52 @@
+// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+#include "platform/globals.h"
+#if defined(TARGET_OS_MACOS)
+
+#include <termios.h>  // NOLINT
+
+#include "bin/stdin.h"
+
+
+namespace dart {
+namespace bin {
+
+int Stdin::ReadByte() {
+  int c = getchar();
+  if (c == EOF) {
+    c = -1;
+  }
+  return c;
+}
+
+
+void Stdin::SetEchoMode(bool enabled) {
+  struct termios term;
+  tcgetattr(fileno(stdin), &term);
+  if (enabled) {
+    term.c_lflag |= ECHO|ECHONL;
+  } else {
+    term.c_lflag &= ~(ECHO|ECHONL);
+  }
+  tcsetattr(fileno(stdin), TCSANOW, &term);
+}
+
+
+void Stdin::SetLineMode(bool enabled) {
+  struct termios term;
+  tcgetattr(fileno(stdin), &term);
+  if (enabled) {
+    term.c_lflag |= ICANON;
+  } else {
+    term.c_lflag &= ~(ICANON);
+  }
+  tcsetattr(fileno(stdin), TCSANOW, &term);
+}
+
+}  // namespace bin
+}  // namespace dart
+
+#endif  // defined(TARGET_OS_MACOS)
+