Error reporting on File in dart:io

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 "bin/thread.h"
 
@@ skipping 54 matching lines @@
       DartUtils::GetStringValue(Dart_GetNativeArgument(args, 0));
   int mode = DartUtils::GetIntegerValue(Dart_GetNativeArgument(args, 1));
   File::DartFileOpenMode dart_file_mode =
       static_cast<File::DartFileOpenMode>(mode);
   File::FileOpenMode file_mode = File::DartModeToFileMode(dart_file_mode);
   // Check that the file exists before opening it only for
   // reading. This is to prevent the opening of directories as
   // files. Directories can be opened for reading using the posix
   // 'open' call.
   File* file = NULL;
-  if (((file_mode & File::kWrite) != 0) || File::Exists(filename)) {
-    file = File::Open(filename, file_mode);
+  OSError os_error;
+  file = File::Open(filename, file_mode, &os_error);
+  if (file == NULL) {
+    Dart_Handle os_error_handle = Dart_GetNativeArgument(args, 2);
+    DartUtils::SetIntegerInstanceField(
+        os_error_handle, "errorCode", os_error.errno_);
+    DartUtils::SetStringInstanceField(
+        os_error_handle, "message", os_error.strerror_);
   }
   Dart_SetReturnValue(args, Dart_NewInteger(reinterpret_cast<intptr_t>(file)));
   Dart_ExitScope();
 }
 
 
 void FUNCTION_NAME(File_Exists)(Dart_NativeArguments args) {
   Dart_EnterScope();
   const char* filename =
       DartUtils::GetStringValue(Dart_GetNativeArgument(args, 0));
@@ skipping 319 matching lines @@
 
 static CObject* FileCreateRequest(const CObjectArray& request) {
   if (request.Length() == 2 && request[1]->IsString()) {
     CObjectString filename(request[1]);
     bool result = File::Create(filename.CString());
     return CObject::Bool(result);
   }
   return CObject::False();
 }
 
+static CObject* MakeOsError(OSError os_error) {
+  CObject* error_message =
+      new CObjectString(CObject::NewString(os_error.strerror_));
+  CObjectArray* result = new CObjectArray(CObject::NewArray(2));
+  result->SetAt(0, new CObjectInt32(CObject::NewInt32(os_error.errno_)));
+  result->SetAt(1, error_message);
+  return result;
+}
 
 static CObject* FileOpenRequest(const CObjectArray& request) {
   File* file = NULL;
+  OSError os_error;
   if (request.Length() == 3 &&
       request[1]->IsString() &&
       request[2]->IsInt32()) {
     CObjectString filename(request[1]);
     CObjectInt32 mode(request[2]);
     File::DartFileOpenMode dart_file_mode =
         static_cast<File::DartFileOpenMode>(mode.Value());
     File::FileOpenMode file_mode = File::DartModeToFileMode(dart_file_mode);
-    if (((file_mode & File::kWrite) != 0) || File::Exists(filename.CString())) {
-      file = File::Open(filename.CString(), file_mode);
-    }
+    file = File::Open(filename.CString(), file_mode, &os_error);
   }
-  return new CObjectIntptr(
-      CObject::NewIntptr(reinterpret_cast<intptr_t>(file)));
+  if (file != NULL) {
+    return new CObjectIntptr(
+        CObject::NewIntptr(reinterpret_cast<intptr_t>(file)));
+  } else {
+    return MakeOsError(os_error);
+  }
 }
 
 
 static CObject* FileDeleteRequest(const CObjectArray& request) {
   if (request.Length() == 2 && request[1]->IsString()) {
     CObjectString filename(request[1]);
     bool result = File::Delete(filename.CString());
     return CObject::Bool(result);
   }
   return CObject::False();
@@ skipping 316 matching lines @@
   Dart_EnterScope();
   Dart_SetReturnValue(args, Dart_Null());
   Dart_Port service_port = File::GetServicePort();
   if (service_port != kIllegalPort) {
     // Return a send port for the service port.
     Dart_Handle send_port = Dart_NewSendPort(service_port);
     Dart_SetReturnValue(args, send_port);
   }
   Dart_ExitScope();
 }