Implement File.directory() and File.directorySync() to get

runtime/bin/file.cc

 // Copyright (c) 2012, 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 "bin/file.h"
 
 #include "bin/builtin.h"
 #include "bin/dartutils.h"
 
 #include "include/dart_api.h"
@@ skipping 302 matching lines @@
 void FUNCTION_NAME(File_Delete)(Dart_NativeArguments args) {
   Dart_EnterScope();
   const char* str =
       DartUtils::GetStringValue(Dart_GetNativeArgument(args, 0));
   bool result = File::Delete(str);
   Dart_SetReturnValue(args, Dart_NewBoolean(result));
   Dart_ExitScope();
 }
 
 
+void FUNCTION_NAME(File_Directory)(Dart_NativeArguments args) {
+  Dart_EnterScope();
+  const char* str =
+      DartUtils::GetStringValue(Dart_GetNativeArgument(args, 0));
+  char* str_copy = strdup(str);
+  char* path = File::GetContainingDirectory(str_copy);
+  if (path != NULL) {
+    Dart_SetReturnValue(args, Dart_NewString(path));
+  }
+  free(str_copy);
+  free(path);
+  Dart_ExitScope();
+}
+
+
 void FUNCTION_NAME(File_FullPath)(Dart_NativeArguments args) {
   Dart_EnterScope();
   const char* str =
       DartUtils::GetStringValue(Dart_GetNativeArgument(args, 0));
   char* path = File::GetCanonicalPath(str);
   if (path != NULL) {
     Dart_SetReturnValue(args, Dart_NewString(path));
     free(path);
   }
   Dart_ExitScope();
 }
 
 
 void FUNCTION_NAME(File_OpenStdio)(Dart_NativeArguments args) {
   Dart_EnterScope();
   int fd = DartUtils::GetIntegerValue(Dart_GetNativeArgument(args, 0));
   File* file = File::OpenStdio(fd);
   Dart_SetReturnValue(args, Dart_NewInteger(reinterpret_cast<intptr_t>(file)));
   Dart_ExitScope();
 }
 
 
 void FUNCTION_NAME(File_GetStdioHandleType)(Dart_NativeArguments args) {
   Dart_EnterScope();
   int fd = DartUtils::GetIntegerValue(Dart_GetNativeArgument(args, 0));
   File::StdioHandleType type = File::GetStdioHandleType(fd);
   Dart_SetReturnValue(args, Dart_NewInteger(type));
   Dart_ExitScope();
 }