[dart:io] Namespaces for file IO

runtime/bin/namespace_macos.cc

+// Copyright (c) 2017, 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(HOST_OS_MACOS)
+
+#include "bin/namespace.h"
+
+#include <errno.h>
+#include <fcntl.h>
+
+#include "bin/fdutils.h"
+#include "platform/signal_blocker.h"
+
+namespace dart {
+namespace bin {
+
+Namespace* Namespace::Create(const char* path) {
+  UNIMPLEMENTED();
+  return NULL;
+}
+
+Namespace::~Namespace() {
+  if (namespc_ != kNone) {
+    VOID_TEMP_FAILURE_RETRY(close(namespc_));
+  }
+}
+
+intptr_t Namespace::Default() {
+  return kNone;
+}
+
+const char* Namespace::GetCurrent(Namespace* namespc) {
+  char buffer[PATH_MAX];
+  if (getcwd(buffer, PATH_MAX) == NULL) {
+    return NULL;
+  }
+  return DartUtils::ScopedCopyCString(buffer);
+}
+
+bool Namespace::SetCurrent(Namespace* namespc, const char* path) {
+  int result = NO_RETRY_EXPECTED(chdir(path));
+  return (result == 0);
+}
+
+bool Namespace::ResolvePath(Namespace* namespc, const char* path,
+                            intptr_t* dirfd, const char** resolved_path) {
+  UNIMPLEMENTED();
+  return false;
+}
+
+NamespaceScope::NamespaceScope(Namespace* namespc, const char* path) {
+  UNIMPLEMENTED();
+}
+
+NamespaceScope::~NamespaceScope() {
+  UNIMPLEMENTED();
+}
+
+}  // namespace bin
+}  // namespace dart
+
+#endif  // defined(HOST_OS_MACOS)