[dart:io] Namespaces for file IO

runtime/bin/file.cc

 // 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 "bin/file.h"
 
 #include "bin/builtin.h"
 #include "bin/dartutils.h"
 #include "bin/embedded_dart_io.h"
 #include "bin/io_buffer.h"
+#include "bin/namespace.h"
 #include "bin/utils.h"
 #include "include/dart_api.h"
 #include "include/dart_tools_api.h"
 #include "platform/globals.h"
 
 namespace dart {
 namespace bin {
 
 static const int kFileNativeFieldIndex = 0;
 
 // The file pointer has been passed into Dart as an intptr_t and it is safe
 // to pull it out of Dart as a 64-bit integer, cast it to an intptr_t and
 // from there to a File pointer.
 static File* GetFile(Dart_NativeArguments args) {
   File* file;
   Dart_Handle dart_this = ThrowIfError(Dart_GetNativeArgument(args, 0));
   ASSERT(Dart_IsInstance(dart_this));
-  ThrowIfError(Dart_GetNativeInstanceField(dart_this, kFileNativeFieldIndex,
-                                           reinterpret_cast<intptr_t*>(&file)));
+  Dart_Handle result = Dart_GetNativeInstanceField(dart_this, kFileNativeFieldIndex,
+                                           reinterpret_cast<intptr_t*>(&file));
+  ASSERT(!Dart_IsError(result));
   return file;
 }
 
 static void SetFile(Dart_Handle dart_this, intptr_t file_pointer) {
   Dart_Handle result = Dart_SetNativeInstanceField(
       dart_this, kFileNativeFieldIndex, file_pointer);
   if (Dart_IsError(result)) {
     Log::PrintErr("SetNativeInstanceField in SetFile() failed\n");
     Dart_PropagateError(result);
   }
@@ skipping 23 matching lines @@
   intptr_t file_pointer =
       DartUtils::GetIntptrValue(Dart_GetNativeArgument(args, 1));
   File* file = reinterpret_cast<File*>(file_pointer);
   Dart_WeakPersistentHandle handle = Dart_NewWeakPersistentHandle(
       dart_this, reinterpret_cast<void*>(file), sizeof(*file), ReleaseFile);
   file->SetWeakHandle(handle);
   SetFile(dart_this, file_pointer);
 }
 
 void FUNCTION_NAME(File_Open)(Dart_NativeArguments args) {
+  Namespace* namespc = Namespace::GetNamespace(args, 0);
   const char* filename =
-      DartUtils::GetStringValue(Dart_GetNativeArgument(args, 0));
-  int64_t mode = DartUtils::GetIntegerValue(Dart_GetNativeArgument(args, 1));
+      DartUtils::GetStringValue(Dart_GetNativeArgument(args, 1));
+  int64_t mode = DartUtils::GetIntegerValue(Dart_GetNativeArgument(args, 2));
   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 = File::Open(filename, file_mode);
+  File* file = File::Open(namespc, filename, file_mode);
   if (file != NULL) {
     Dart_SetReturnValue(args,
                         Dart_NewInteger(reinterpret_cast<intptr_t>(file)));
   } else {
     Dart_SetReturnValue(args, DartUtils::NewDartOSError());
   }
 }
 
 void FUNCTION_NAME(File_Exists)(Dart_NativeArguments args) {
+  Namespace* namespc = Namespace::GetNamespace(args, 0);
   const char* filename =
-      DartUtils::GetStringValue(Dart_GetNativeArgument(args, 0));
-  bool exists = File::Exists(filename);
+      DartUtils::GetStringValue(Dart_GetNativeArgument(args, 1));
+  bool exists = File::Exists(namespc, filename);
   Dart_SetReturnValue(args, Dart_NewBoolean(exists));
 }
 
 void FUNCTION_NAME(File_Close)(Dart_NativeArguments args) {
   File* file = GetFile(args);
   ASSERT(file != NULL);
   file->Close();
   file->DeleteWeakHandle(Dart_CurrentIsolate());
   file->Release();
 
@@ skipping 199 matching lines @@
   ASSERT(file != NULL);
   int64_t return_value = file->Length();
   if (return_value >= 0) {
     Dart_SetReturnValue(args, Dart_NewInteger(return_value));
   } else {
     Dart_SetReturnValue(args, DartUtils::NewDartOSError());
   }
 }
 
 void FUNCTION_NAME(File_LengthFromPath)(Dart_NativeArguments args) {
-  const char* path = DartUtils::GetStringValue(Dart_GetNativeArgument(args, 0));
-  int64_t return_value = File::LengthFromPath(path);
+  Namespace* namespc = Namespace::GetNamespace(args, 0);
+  const char* path = DartUtils::GetStringValue(Dart_GetNativeArgument(args, 1));
+  int64_t return_value = File::LengthFromPath(namespc, path);
   if (return_value >= 0) {
     Dart_SetReturnValue(args, Dart_NewInteger(return_value));
   } else {
     Dart_SetReturnValue(args, DartUtils::NewDartOSError());
   }
 }
 
 void FUNCTION_NAME(File_LastModified)(Dart_NativeArguments args) {
-  const char* name = DartUtils::GetStringValue(Dart_GetNativeArgument(args, 0));
-  int64_t return_value = File::LastModified(name);
+  Namespace* namespc = Namespace::GetNamespace(args, 0);
+  const char* name = DartUtils::GetStringValue(Dart_GetNativeArgument(args, 1));
+  int64_t return_value = File::LastModified(namespc, name);
   if (return_value >= 0) {
     Dart_SetReturnValue(args,
                         Dart_NewInteger(return_value * kMillisecondsPerSecond));
   } else {
     Dart_SetReturnValue(args, DartUtils::NewDartOSError());
   }
 }
 
 void FUNCTION_NAME(File_SetLastModified)(Dart_NativeArguments args) {
-  const char* name = DartUtils::GetStringValue(Dart_GetNativeArgument(args, 0));
+  Namespace* namespc = Namespace::GetNamespace(args, 0);
+  const char* name = DartUtils::GetStringValue(Dart_GetNativeArgument(args, 1));
   int64_t millis;
-  if (!DartUtils::GetInt64Value(Dart_GetNativeArgument(args, 1), &millis)) {
+  if (!DartUtils::GetInt64Value(Dart_GetNativeArgument(args, 2), &millis)) {
     Dart_ThrowException(DartUtils::NewDartArgumentError(
         "The second argument must be a 64-bit int."));
   }
-  if (!File::SetLastModified(name, millis)) {
+  if (!File::SetLastModified(namespc, name, millis)) {
     Dart_SetReturnValue(args, DartUtils::NewDartOSError());
   }
 }
 
 void FUNCTION_NAME(File_LastAccessed)(Dart_NativeArguments args) {
-  const char* name = DartUtils::GetStringValue(Dart_GetNativeArgument(args, 0));
-  int64_t return_value = File::LastAccessed(name);
+  Namespace* namespc = Namespace::GetNamespace(args, 0);
+  const char* name = DartUtils::GetStringValue(Dart_GetNativeArgument(args, 1));
+  int64_t return_value = File::LastAccessed(namespc, name);
   if (return_value >= 0) {
     Dart_SetReturnValue(args,
                         Dart_NewInteger(return_value * kMillisecondsPerSecond));
   } else {
     Dart_SetReturnValue(args, DartUtils::NewDartOSError());
   }
 }
 
 void FUNCTION_NAME(File_SetLastAccessed)(Dart_NativeArguments args) {
-  const char* name = DartUtils::GetStringValue(Dart_GetNativeArgument(args, 0));
+  Namespace* namespc = Namespace::GetNamespace(args, 0);
+  const char* name = DartUtils::GetStringValue(Dart_GetNativeArgument(args, 1));
   int64_t millis;
-  if (!DartUtils::GetInt64Value(Dart_GetNativeArgument(args, 1), &millis)) {
+  if (!DartUtils::GetInt64Value(Dart_GetNativeArgument(args, 2), &millis)) {
     Dart_ThrowException(DartUtils::NewDartArgumentError(
         "The second argument must be a 64-bit int."));
   }
-  if (!File::SetLastAccessed(name, millis)) {
+  if (!File::SetLastAccessed(namespc, name, millis)) {
     Dart_SetReturnValue(args, DartUtils::NewDartOSError());
   }
 }
 
 void FUNCTION_NAME(File_Flush)(Dart_NativeArguments args) {
   File* file = GetFile(args);
   ASSERT(file != NULL);
   if (file->Flush()) {
     Dart_SetReturnValue(args, Dart_True());
   } else {
@@ skipping 18 matching lines @@
         Dart_SetReturnValue(args, DartUtils::NewDartOSError());
       }
       return;
     }
   }
   OSError os_error(-1, "Invalid argument", OSError::kUnknown);
   Dart_SetReturnValue(args, DartUtils::NewDartOSError(&os_error));
 }
 
 void FUNCTION_NAME(File_Create)(Dart_NativeArguments args) {
-  const char* str = DartUtils::GetStringValue(Dart_GetNativeArgument(args, 0));
-  bool result = File::Create(str);
+  Namespace* namespc = Namespace::GetNamespace(args, 0);
+  const char* str = DartUtils::GetStringValue(Dart_GetNativeArgument(args, 1));
+  bool result = File::Create(namespc, str);
   if (result) {
     Dart_SetReturnValue(args, Dart_NewBoolean(result));
   } else {
     Dart_SetReturnValue(args, DartUtils::NewDartOSError());
   }
 }
 
 void FUNCTION_NAME(File_CreateLink)(Dart_NativeArguments args) {
-  if (Dart_IsString(Dart_GetNativeArgument(args, 0)) &&
-      Dart_IsString(Dart_GetNativeArgument(args, 1))) {
+  Namespace* namespc = Namespace::GetNamespace(args, 0);
+  if (Dart_IsString(Dart_GetNativeArgument(args, 1)) &&
+      Dart_IsString(Dart_GetNativeArgument(args, 2))) {
     const char* name =
-        DartUtils::GetStringValue(Dart_GetNativeArgument(args, 0));
+        DartUtils::GetStringValue(Dart_GetNativeArgument(args, 1));
     const char* target =
-        DartUtils::GetStringValue(Dart_GetNativeArgument(args, 1));
-    if (!File::CreateLink(name, target)) {
+        DartUtils::GetStringValue(Dart_GetNativeArgument(args, 2));
+    if (!File::CreateLink(namespc, name, target)) {
       Dart_SetReturnValue(args, DartUtils::NewDartOSError());
     }
   } else {
     Dart_Handle err =
         DartUtils::NewDartArgumentError("Non-string argument to Link.create");
     Dart_SetReturnValue(args, err);
   }
 }
 
 void FUNCTION_NAME(File_LinkTarget)(Dart_NativeArguments args) {
-  if (Dart_IsString(Dart_GetNativeArgument(args, 0))) {
+  Namespace* namespc = Namespace::GetNamespace(args, 0);
+  if (Dart_IsString(Dart_GetNativeArgument(args, 1))) {
     const char* name =
-        DartUtils::GetStringValue(Dart_GetNativeArgument(args, 0));
-    const char* target = File::LinkTarget(name);
+        DartUtils::GetStringValue(Dart_GetNativeArgument(args, 1));
+    const char* target = File::LinkTarget(namespc, name);
     if (target == NULL) {
       Dart_SetReturnValue(args, DartUtils::NewDartOSError());
     } else {
       Dart_SetReturnValue(args, DartUtils::NewString(target));
     }
   } else {
     Dart_Handle err =
         DartUtils::NewDartArgumentError("Non-string argument to Link.target");
     Dart_SetReturnValue(args, err);
   }
 }
 
 void FUNCTION_NAME(File_Delete)(Dart_NativeArguments args) {
-  const char* str = DartUtils::GetStringValue(Dart_GetNativeArgument(args, 0));
-  bool result = File::Delete(str);
+  Namespace* namespc = Namespace::GetNamespace(args, 0);
+  const char* str = DartUtils::GetStringValue(Dart_GetNativeArgument(args, 1));
+  bool result = File::Delete(namespc, str);
   if (result) {
     Dart_SetReturnValue(args, Dart_NewBoolean(result));
   } else {
     Dart_SetReturnValue(args, DartUtils::NewDartOSError());
   }
 }
 
 void FUNCTION_NAME(File_DeleteLink)(Dart_NativeArguments args) {
-  const char* str = DartUtils::GetStringValue(Dart_GetNativeArgument(args, 0));
-  bool result = File::DeleteLink(str);
+  Namespace* namespc = Namespace::GetNamespace(args, 0);
+  const char* str = DartUtils::GetStringValue(Dart_GetNativeArgument(args, 1));
+  bool result = File::DeleteLink(namespc, str);
   if (result) {
     Dart_SetReturnValue(args, Dart_NewBoolean(result));
   } else {
     Dart_SetReturnValue(args, DartUtils::NewDartOSError());
   }
 }
 
 void FUNCTION_NAME(File_Rename)(Dart_NativeArguments args) {
+  Namespace* namespc = Namespace::GetNamespace(args, 0);
   const char* old_path =
-      DartUtils::GetStringValue(Dart_GetNativeArgument(args, 0));
+      DartUtils::GetStringValue(Dart_GetNativeArgument(args, 1));
   const char* new_path =
-      DartUtils::GetStringValue(Dart_GetNativeArgument(args, 1));
-  bool result = File::Rename(old_path, new_path);
+      DartUtils::GetStringValue(Dart_GetNativeArgument(args, 2));
+  bool result = File::Rename(namespc, old_path, new_path);
   if (result) {
     Dart_SetReturnValue(args, Dart_NewBoolean(result));
   } else {
     Dart_SetReturnValue(args, DartUtils::NewDartOSError());
   }
 }
 
 void FUNCTION_NAME(File_RenameLink)(Dart_NativeArguments args) {
+  Namespace* namespc = Namespace::GetNamespace(args, 0);
   const char* old_path =
-      DartUtils::GetStringValue(Dart_GetNativeArgument(args, 0));
+      DartUtils::GetStringValue(Dart_GetNativeArgument(args, 1));
   const char* new_path =
-      DartUtils::GetStringValue(Dart_GetNativeArgument(args, 1));
-  bool result = File::RenameLink(old_path, new_path);
+      DartUtils::GetStringValue(Dart_GetNativeArgument(args, 2));
+  bool result = File::RenameLink(namespc, old_path, new_path);
   if (result) {
     Dart_SetReturnValue(args, Dart_NewBoolean(result));
   } else {
     Dart_SetReturnValue(args, DartUtils::NewDartOSError());
   }
 }
 
 void FUNCTION_NAME(File_Copy)(Dart_NativeArguments args) {
+  Namespace* namespc = Namespace::GetNamespace(args, 0);
   const char* old_path =
-      DartUtils::GetStringValue(Dart_GetNativeArgument(args, 0));
+      DartUtils::GetStringValue(Dart_GetNativeArgument(args, 1));
   const char* new_path =
-      DartUtils::GetStringValue(Dart_GetNativeArgument(args, 1));
-  bool result = File::Copy(old_path, new_path);
+      DartUtils::GetStringValue(Dart_GetNativeArgument(args, 2));
+  bool result = File::Copy(namespc, old_path, new_path);
   if (result) {
     Dart_SetReturnValue(args, Dart_NewBoolean(result));
   } else {
     Dart_SetReturnValue(args, DartUtils::NewDartOSError());
   }
 }
 
 void FUNCTION_NAME(File_ResolveSymbolicLinks)(Dart_NativeArguments args) {
-  const char* str = DartUtils::GetStringValue(Dart_GetNativeArgument(args, 0));
-  const char* path = File::GetCanonicalPath(str);
+  Namespace* namespc = Namespace::GetNamespace(args, 0);
+  const char* str = DartUtils::GetStringValue(Dart_GetNativeArgument(args, 1));
+  const char* path = File::GetCanonicalPath(namespc, str);
   if (path != NULL) {
     Dart_SetReturnValue(args, DartUtils::NewString(path));
   } else {
     Dart_SetReturnValue(args, DartUtils::NewDartOSError());
   }
 }
 
 void FUNCTION_NAME(File_OpenStdio)(Dart_NativeArguments args) {
   int64_t fd = DartUtils::GetIntegerValue(Dart_GetNativeArgument(args, 0));
   ASSERT((fd == STDIN_FILENO) || (fd == STDOUT_FILENO) ||
          (fd == STDERR_FILENO));
   File* file = File::OpenStdio(static_cast<int>(fd));
   Dart_SetReturnValue(args, Dart_NewInteger(reinterpret_cast<intptr_t>(file)));
 }
 
 void FUNCTION_NAME(File_GetStdioHandleType)(Dart_NativeArguments args) {
   int64_t fd = DartUtils::GetIntegerValue(Dart_GetNativeArgument(args, 0));
   ASSERT((fd == STDIN_FILENO) || (fd == STDOUT_FILENO) ||
          (fd == STDERR_FILENO));
   File::StdioHandleType type = File::GetStdioHandleType(static_cast<int>(fd));
   Dart_SetReturnValue(args, Dart_NewInteger(type));
 }
 
 void FUNCTION_NAME(File_GetType)(Dart_NativeArguments args) {
-  if (Dart_IsString(Dart_GetNativeArgument(args, 0)) &&
-      Dart_IsBoolean(Dart_GetNativeArgument(args, 1))) {
+  Namespace* namespc = Namespace::GetNamespace(args, 0);
+  if (Dart_IsString(Dart_GetNativeArgument(args, 1)) &&
+      Dart_IsBoolean(Dart_GetNativeArgument(args, 2))) {
     const char* str =
-        DartUtils::GetStringValue(Dart_GetNativeArgument(args, 0));
+        DartUtils::GetStringValue(Dart_GetNativeArgument(args, 1));
     bool follow_links =
-        DartUtils::GetBooleanValue(Dart_GetNativeArgument(args, 1));
-    File::Type type = File::GetType(str, follow_links);
+        DartUtils::GetBooleanValue(Dart_GetNativeArgument(args, 2));
+    File::Type type = File::GetType(namespc, str, follow_links);
     Dart_SetReturnValue(args, Dart_NewInteger(static_cast<int>(type)));
   } else {
     Dart_Handle err = DartUtils::NewDartArgumentError(
         "Non-string argument to FileSystemEntity.type");
     Dart_SetReturnValue(args, err);
   }
 }
 
 void FUNCTION_NAME(File_Stat)(Dart_NativeArguments args) {
-  if (Dart_IsString(Dart_GetNativeArgument(args, 0))) {
+  Namespace* namespc = Namespace::GetNamespace(args, 0);
+  if (Dart_IsString(Dart_GetNativeArgument(args, 1))) {
     const char* path =
-        DartUtils::GetStringValue(Dart_GetNativeArgument(args, 0));
+        DartUtils::GetStringValue(Dart_GetNativeArgument(args, 1));
 
     int64_t stat_data[File::kStatSize];
-    File::Stat(path, stat_data);
+    File::Stat(namespc, path, stat_data);
     if (stat_data[File::kType] == File::kDoesNotExist) {
       Dart_SetReturnValue(args, DartUtils::NewDartOSError());
     } else {
       Dart_Handle returned_data =
           Dart_NewTypedData(Dart_TypedData_kInt64, File::kStatSize);
       if (Dart_IsError(returned_data)) {
         Dart_PropagateError(returned_data);
       }
       Dart_TypedData_Type data_type_unused;
       void* data_location;
@@ skipping 12 matching lines @@
       Dart_SetReturnValue(args, returned_data);
     }
   } else {
     Dart_Handle err = DartUtils::NewDartArgumentError(
         "Non-string argument to FileSystemEntity.stat");
     Dart_SetReturnValue(args, err);
   }
 }
 
 void FUNCTION_NAME(File_AreIdentical)(Dart_NativeArguments args) {
-  if (Dart_IsString(Dart_GetNativeArgument(args, 0)) &&
-      Dart_IsString(Dart_GetNativeArgument(args, 1))) {
+  Namespace* namespc = Namespace::GetNamespace(args, 0);
+  if (Dart_IsString(Dart_GetNativeArgument(args, 1)) &&
+      Dart_IsString(Dart_GetNativeArgument(args, 2))) {
     const char* path_1 =
-        DartUtils::GetStringValue(Dart_GetNativeArgument(args, 0));
+        DartUtils::GetStringValue(Dart_GetNativeArgument(args, 1));
     const char* path_2 =
-        DartUtils::GetStringValue(Dart_GetNativeArgument(args, 1));
-    File::Identical result = File::AreIdentical(path_1, path_2);
+        DartUtils::GetStringValue(Dart_GetNativeArgument(args, 2));
+    File::Identical result = File::AreIdentical(namespc, path_1, path_2);
     if (result == File::kError) {
       Dart_SetReturnValue(args, DartUtils::NewDartOSError());
     } else {
       Dart_SetReturnValue(args, Dart_NewBoolean(result == File::kIdentical));
     }
   } else {
     Dart_Handle err = DartUtils::NewDartArgumentError(
         "Non-string argument to FileSystemEntity.identical");
     Dart_SetReturnValue(args, err);
   }
 }
 
 static int64_t CObjectInt32OrInt64ToInt64(CObject* cobject) {
   ASSERT(cobject->IsInt32OrInt64());
   int64_t result;
   if (cobject->IsInt32()) {
     CObjectInt32 value(cobject);
     result = value.Value();
   } else {
     CObjectInt64 value(cobject);
     result = value.Value();
   }
   return result;
 }
 
-File* CObjectToFilePointer(CObject* cobject) {
+static File* CObjectToFilePointer(CObject* cobject) {
   CObjectIntptr value(cobject);
   return reinterpret_cast<File*>(value.Value());
 }
 
+static Namespace* CObjectToNamespacePointer(CObject* cobject) {
+  CObjectIntptr value(cobject);
+  return reinterpret_cast<Namespace*>(value.Value());
+}
+
 CObject* File::ExistsRequest(const CObjectArray& request) {
-  if ((request.Length() == 1) && request[0]->IsString()) {
-    CObjectString filename(request[0]);
-    bool result = File::Exists(filename.CString());
-    return CObject::Bool(result);
-  }
-  return CObject::IllegalArgumentError();
+  if ((request.Length() < 1) || !request[0]->IsIntptr()) {
+    return CObject::IllegalArgumentError();
+  }
+  Namespace* namespc = CObjectToNamespacePointer(request[0]);
+  RefCntReleaseScope<Namespace> rs(namespc);
+  if ((request.Length() != 2) || !request[1]->IsString()) {
+    return CObject::IllegalArgumentError();
+  }
+  CObjectString filename(request[1]);
+  return CObject::Bool(File::Exists(namespc, filename.CString()));
 }
 
 CObject* File::CreateRequest(const CObjectArray& request) {
-  if ((request.Length() == 1) && request[0]->IsString()) {
-    CObjectString filename(request[0]);
-    bool result = File::Create(filename.CString());
-    if (result) {
-      return CObject::True();
-    } else {
-      return CObject::NewOSError();
-    }
-  }
-  return CObject::IllegalArgumentError();
+  if ((request.Length() < 1) || !request[0]->IsIntptr()) {
+    return CObject::IllegalArgumentError();
+  }
+  Namespace* namespc = CObjectToNamespacePointer(request[0]);
+  RefCntReleaseScope<Namespace> rs(namespc);
+  if ((request.Length() != 2) || !request[1]->IsString()) {
+    return CObject::IllegalArgumentError();
+  }
+  CObjectString filename(request[1]);
+  return File::Create(namespc, filename.CString()) ? CObject::True()
+                                                   : CObject::NewOSError();
 }
 
 CObject* File::OpenRequest(const CObjectArray& request) {
-  File* file = NULL;
-  if ((request.Length() == 2) && request[0]->IsString() &&
-      request[1]->IsInt32()) {
-    CObjectString filename(request[0]);
-    CObjectInt32 mode(request[1]);
-    File::DartFileOpenMode dart_file_mode =
-        static_cast<File::DartFileOpenMode>(mode.Value());
-    File::FileOpenMode file_mode = File::DartModeToFileMode(dart_file_mode);
-    file = File::Open(filename.CString(), file_mode);
-    if (file != NULL) {
-      return new CObjectIntptr(
-          CObject::NewIntptr(reinterpret_cast<intptr_t>(file)));
-    } else {
-      return CObject::NewOSError();
-    }
-  }
-  return CObject::IllegalArgumentError();
+  if ((request.Length() < 1) || !request[0]->IsIntptr()) {
+    return CObject::IllegalArgumentError();
+  }
+  Namespace* namespc = CObjectToNamespacePointer(request[0]);
+  RefCntReleaseScope<Namespace> rs(namespc);
+  if ((request.Length() != 3) ||
+      !request[1]->IsString() ||
+      !request[2]->IsInt32()) {
+    return CObject::IllegalArgumentError();
+  }
+  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);
+  File* file = File::Open(namespc, filename.CString(), file_mode);
+  if (file == NULL) {
+    return CObject::NewOSError();
+  }
+  return new CObjectIntptr(
+      CObject::NewIntptr(reinterpret_cast<intptr_t>(file)));
 }
 
 CObject* File::DeleteRequest(const CObjectArray& request) {
-  if ((request.Length() == 1) && request[0]->IsString()) {
-    CObjectString filename(request[0]);
-    bool result = File::Delete(filename.CString());
-    if (result) {
-      return CObject::True();
-    } else {
-      return CObject::NewOSError();
-    }
-  }
-  return CObject::False();
+  if ((request.Length() < 1) || !request[0]->IsIntptr()) {
+    return CObject::False();
+  }
+  Namespace* namespc = CObjectToNamespacePointer(request[0]);
+  RefCntReleaseScope<Namespace> rs(namespc);
+  if ((request.Length() != 2) || !request[1]->IsString()) {
+    return CObject::False();
+  }
+  CObjectString filename(request[1]);
+  return File::Delete(namespc, filename.CString()) ? CObject::True()
+                                                   : CObject::NewOSError();
 }
 
 CObject* File::RenameRequest(const CObjectArray& request) {
-  if ((request.Length() == 2) && request[0]->IsString() &&
-      request[1]->IsString()) {
-    CObjectString old_path(request[0]);
-    CObjectString new_path(request[1]);
-    bool completed = File::Rename(old_path.CString(), new_path.CString());
-    if (completed) {
-      return CObject::True();
-    }
-    return CObject::NewOSError();
-  }
-  return CObject::IllegalArgumentError();
+  if ((request.Length() < 1) || !request[0]->IsIntptr()) {
+    return CObject::IllegalArgumentError();
+  }
+  Namespace* namespc = CObjectToNamespacePointer(request[0]);
+  RefCntReleaseScope<Namespace> rs(namespc);
+  if ((request.Length() != 3) ||
+      !request[1]->IsString() ||
+      !request[2]->IsString()) {
+    return CObject::IllegalArgumentError();
+  }
+  CObjectString old_path(request[1]);
+  CObjectString new_path(request[2]);
+  return File::Rename(namespc, old_path.CString(), new_path.CString())
+         ? CObject::True()
+         : CObject::NewOSError();
 }
 
 CObject* File::CopyRequest(const CObjectArray& request) {
-  if ((request.Length() == 2) && request[0]->IsString() &&
-      request[1]->IsString()) {
-    CObjectString old_path(request[0]);
-    CObjectString new_path(request[1]);
-    bool completed = File::Copy(old_path.CString(), new_path.CString());
-    if (completed) {
-      return CObject::True();
-    }
-    return CObject::NewOSError();
-  }
-  return CObject::IllegalArgumentError();
+  if ((request.Length() < 1) || !request[0]->IsIntptr()) {
+    return CObject::IllegalArgumentError();
+  }
+  Namespace* namespc = CObjectToNamespacePointer(request[0]);
+  RefCntReleaseScope<Namespace> rs(namespc);
+  if ((request.Length() != 3) ||
+      !request[1]->IsString() ||
+      !request[2]->IsString()) {
+    return CObject::IllegalArgumentError();
+  }
+  CObjectString old_path(request[1]);
+  CObjectString new_path(request[2]);
+  return File::Copy(namespc, old_path.CString(), new_path.CString())
+         ? CObject::True()
+         : CObject::NewOSError();
 }
 
 CObject* File::ResolveSymbolicLinksRequest(const CObjectArray& request) {
-  if ((request.Length() == 1) && request[0]->IsString()) {
-    CObjectString filename(request[0]);
-    const char* result = File::GetCanonicalPath(filename.CString());
-    if (result != NULL) {
-      CObject* path = new CObjectString(CObject::NewString(result));
-      return path;
-    } else {
-      return CObject::NewOSError();
-    }
-  }
-  return CObject::IllegalArgumentError();
+  if ((request.Length() < 1) || !request[0]->IsIntptr()) {
+    return CObject::IllegalArgumentError();
+  }
+  Namespace* namespc = CObjectToNamespacePointer(request[0]);
+  RefCntReleaseScope<Namespace> rs(namespc);
+  if ((request.Length() != 2) || !request[1]->IsString()) {
+    return CObject::IllegalArgumentError();
+  }
+  CObjectString filename(request[1]);
+  const char* result = File::GetCanonicalPath(namespc, filename.CString());
+  if (result == NULL) {
+    return CObject::NewOSError();
+  }
+  return new CObjectString(CObject::NewString(result));
 }
 
 CObject* File::CloseRequest(const CObjectArray& request) {
-  intptr_t return_value = -1;
-  if ((request.Length() == 1) && request[0]->IsIntptr()) {
-    File* file = CObjectToFilePointer(request[0]);
-    RefCntReleaseScope<File> rs(file);
-    return_value = 0;
-    // We have retained a reference to the file here. Therefore the file's
-    // destructor can't be running. Since no further requests are dispatched by
-    // the Dart code after an async close call, this Close() can't be racing
-    // with any other call on the file. We don't do an extra Release(), and we
-    // don't delete the weak persistent handle. The file is closed here, but the
-    // memory will be cleaned up when the finalizer runs.
-    ASSERT(!file->IsClosed());
-    file->Close();
+  if ((request.Length() != 1) || !request[0]->IsIntptr()) {
+    return new CObjectIntptr(CObject::NewIntptr(-1));
+  }
+  File* file = CObjectToFilePointer(request[0]);
+  RefCntReleaseScope<File> rs(file);
+  // We have retained a reference to the file here. Therefore the file's
+  // destructor can't be running. Since no further requests are dispatched by
+  // the Dart code after an async close call, this Close() can't be racing
+  // with any other call on the file. We don't do an extra Release(), and we
+  // don't delete the weak persistent handle. The file is closed here, but the
+  // memory will be cleaned up when the finalizer runs.
+  ASSERT(!file->IsClosed());
+  file->Close();
+  return new CObjectIntptr(CObject::NewIntptr(0));
+}
+
+CObject* File::PositionRequest(const CObjectArray& request) {
+  if ((request.Length() != 1) || !request[0]->IsIntptr()) {
+    return CObject::IllegalArgumentError();
+  }
+  File* file = CObjectToFilePointer(request[0]);
+  RefCntReleaseScope<File> rs(file);
+  if (file->IsClosed()) {
+    return CObject::FileClosedError();
+  }
+  const intptr_t return_value = file->Position();
+  if (return_value < 0) {
+    return CObject::NewOSError();
   }
   return new CObjectIntptr(CObject::NewIntptr(return_value));
 }
 
-CObject* File::PositionRequest(const CObjectArray& request) {
-  if ((request.Length() == 1) && request[0]->IsIntptr()) {
-    File* file = CObjectToFilePointer(request[0]);
-    RefCntReleaseScope<File> rs(file);
-    if (!file->IsClosed()) {
-      intptr_t return_value = file->Position();
-      if (return_value >= 0) {
-        return new CObjectIntptr(CObject::NewIntptr(return_value));
-      } else {
-        return CObject::NewOSError();
-      }
-    } else {
-      return CObject::FileClosedError();
-    }
-  }
-  return CObject::IllegalArgumentError();
-}
-
 CObject* File::SetPositionRequest(const CObjectArray& request) {
-  if ((request.Length() >= 1) && request[0]->IsIntptr()) {
-    File* file = CObjectToFilePointer(request[0]);
-    RefCntReleaseScope<File> rs(file);
-    if ((request.Length() == 2) && request[1]->IsInt32OrInt64()) {
-      if (!file->IsClosed()) {
-        int64_t position = CObjectInt32OrInt64ToInt64(request[1]);
-        if (file->SetPosition(position)) {
-          return CObject::True();
-        } else {
-          return CObject::NewOSError();
-        }
-      } else {
-        return CObject::FileClosedError();
-      }
-    } else {
-      return CObject::IllegalArgumentError();
-    }
-  }
-  return CObject::IllegalArgumentError();
+  if ((request.Length() < 1) || !request[0]->IsIntptr()) {
+    return CObject::IllegalArgumentError();
+  }
+  File* file = CObjectToFilePointer(request[0]);
+  RefCntReleaseScope<File> rs(file);
+  if ((request.Length() != 2) || !request[1]->IsInt32OrInt64()) {
+    return CObject::IllegalArgumentError();
+  }
+  if (file->IsClosed()) {
+    return CObject::FileClosedError();
+  }
+  const int64_t position = CObjectInt32OrInt64ToInt64(request[1]);
+  return file->SetPosition(position) ? CObject::True() : CObject::NewOSError();
 }
 
 CObject* File::TruncateRequest(const CObjectArray& request) {
-  if ((request.Length() >= 1) && request[0]->IsIntptr()) {
-    File* file = CObjectToFilePointer(request[0]);
-    RefCntReleaseScope<File> rs(file);
-    if ((request.Length() == 2) && request[1]->IsInt32OrInt64()) {
-      if (!file->IsClosed()) {
-        int64_t length = CObjectInt32OrInt64ToInt64(request[1]);
-        if (file->Truncate(length)) {
-          return CObject::True();
-        } else {
-          return CObject::NewOSError();
-        }
-      } else {
-        return CObject::FileClosedError();
-      }
-    } else {
-      return CObject::IllegalArgumentError();
-    }
-  }
-  return CObject::IllegalArgumentError();
+  if ((request.Length() < 1) || !request[0]->IsIntptr()) {
+    return CObject::IllegalArgumentError();
+  }
+  File* file = CObjectToFilePointer(request[0]);
+  RefCntReleaseScope<File> rs(file);
+  if ((request.Length() != 2) || !request[1]->IsInt32OrInt64()) {
+    return CObject::IllegalArgumentError();
+  }
+  if (file->IsClosed()) {
+    return CObject::FileClosedError();
+  }
+  const int64_t length = CObjectInt32OrInt64ToInt64(request[1]);
+  if (file->Truncate(length)) {
+    return CObject::True();
+  }
+  return CObject::NewOSError();
 }
 
 CObject* File::LengthRequest(const CObjectArray& request) {
-  if ((request.Length() == 1) && request[0]->IsIntptr()) {
-    File* file = CObjectToFilePointer(request[0]);
-    RefCntReleaseScope<File> rs(file);
-    if (!file->IsClosed()) {
-      int64_t return_value = file->Length();
-      if (return_value >= 0) {
-        return new CObjectInt64(CObject::NewInt64(return_value));
-      } else {
-        return CObject::NewOSError();
-      }
-    } else {
-      return CObject::FileClosedError();
-    }
-  }
-  return CObject::IllegalArgumentError();
+  if ((request.Length() != 1) || !request[0]->IsIntptr()) {
+    return CObject::IllegalArgumentError();
+  }
+  File* file = CObjectToFilePointer(request[0]);
+  RefCntReleaseScope<File> rs(file);
+  if (file->IsClosed()) {
+    return CObject::FileClosedError();
+  }
+  const int64_t return_value = file->Length();
+  if (return_value < 0) {
+    return CObject::NewOSError();
+  }
+  return new CObjectInt64(CObject::NewInt64(return_value));
 }
 
 CObject* File::LengthFromPathRequest(const CObjectArray& request) {
-  if ((request.Length() == 1) && request[0]->IsString()) {
-    CObjectString filepath(request[0]);
-    int64_t return_value = File::LengthFromPath(filepath.CString());
-    if (return_value >= 0) {
-      return new CObjectInt64(CObject::NewInt64(return_value));
-    } else {
-      return CObject::NewOSError();
-    }
-  }
-  return CObject::IllegalArgumentError();
+  if ((request.Length() < 1) || !request[0]->IsIntptr()) {
+    return CObject::IllegalArgumentError();
+  }
+  Namespace* namespc = CObjectToNamespacePointer(request[0]);
+  RefCntReleaseScope<Namespace> rs(namespc);
+  if ((request.Length() != 2) || !request[1]->IsString()) {
+    return CObject::IllegalArgumentError();
+  }
+  CObjectString filepath(request[1]);
+  const int64_t return_value = File::LengthFromPath(
+      namespc, filepath.CString());
+  if (return_value < 0) {
+    return CObject::NewOSError();
+  }
+  return new CObjectInt64(CObject::NewInt64(return_value));
 }
 
 CObject* File::LastAccessedRequest(const CObjectArray& request) {
-  if ((request.Length() == 1) && request[0]->IsString()) {
-    CObjectString filepath(request[0]);
-    int64_t return_value = File::LastAccessed(filepath.CString());
-    if (return_value >= 0) {
-      return new CObjectIntptr(
-          CObject::NewInt64(return_value * kMillisecondsPerSecond));
-    } else {
-      return CObject::NewOSError();
-    }
-  }
-  return CObject::IllegalArgumentError();
+  if ((request.Length() < 1) || !request[0]->IsIntptr()) {
+    return CObject::IllegalArgumentError();
+  }
+  Namespace* namespc = CObjectToNamespacePointer(request[0]);
+  RefCntReleaseScope<Namespace> rs(namespc);
+  if ((request.Length() != 2) || !request[1]->IsString()) {
+    return CObject::IllegalArgumentError();
+  }
+  CObjectString filepath(request[1]);
+  const int64_t return_value = File::LastAccessed(namespc, filepath.CString());
+  if (return_value < 0) {
+    return CObject::NewOSError();
+  }
+  return new CObjectIntptr(
+      CObject::NewInt64(return_value * kMillisecondsPerSecond));
 }
 
 CObject* File::SetLastAccessedRequest(const CObjectArray& request) {
-  if ((request.Length() == 2) && request[0]->IsString() &&
-      request[1]->IsInt32OrInt64()) {
-    CObjectString filepath(request[0]);
-    const int64_t millis = CObjectInt32OrInt64ToInt64(request[1]);
-    if (File::SetLastAccessed(filepath.CString(), millis)) {
-      return CObject::Null();
-    } else {
-      return CObject::NewOSError();
-    }
-  }
-  return CObject::IllegalArgumentError();
+  if ((request.Length() < 1) || !request[0]->IsIntptr()) {
+    return CObject::IllegalArgumentError();
+  }
+  Namespace* namespc = CObjectToNamespacePointer(request[0]);
+  RefCntReleaseScope<Namespace> rs(namespc);
+  if ((request.Length() != 3) ||
+      !request[1]->IsString() ||
+      !request[2]->IsInt32OrInt64()) {
+    return CObject::IllegalArgumentError();
+  }
+  CObjectString filepath(request[1]);
+  const int64_t millis = CObjectInt32OrInt64ToInt64(request[2]);
+  return File::SetLastAccessed(namespc, filepath.CString(), millis)
+         ? CObject::Null()
+         : CObject::NewOSError();
 }
 
 CObject* File::LastModifiedRequest(const CObjectArray& request) {
-  if ((request.Length() == 1) && request[0]->IsString()) {
-    CObjectString filepath(request[0]);
-    int64_t return_value = File::LastModified(filepath.CString());
-    if (return_value >= 0) {
-      return new CObjectIntptr(
-          CObject::NewInt64(return_value * kMillisecondsPerSecond));
-    } else {
-      return CObject::NewOSError();
-    }
-  }
-  return CObject::IllegalArgumentError();
+  if ((request.Length() < 1) || !request[0]->IsIntptr()) {
+    return CObject::IllegalArgumentError();
+  }
+  Namespace* namespc = CObjectToNamespacePointer(request[0]);
+  RefCntReleaseScope<Namespace> rs(namespc);
+  if ((request.Length() != 2) || !request[1]->IsString()) {
+    return CObject::IllegalArgumentError();
+  }
+  CObjectString filepath(request[1]);
+  const int64_t return_value = File::LastModified(namespc, filepath.CString());
+  if (return_value < 0) {
+    return CObject::NewOSError();
+  }
+  return new CObjectIntptr(
+      CObject::NewInt64(return_value * kMillisecondsPerSecond));
 }
 
 CObject* File::SetLastModifiedRequest(const CObjectArray& request) {
-  if ((request.Length() == 2) && request[0]->IsString() &&
-      request[1]->IsInt32OrInt64()) {
-    CObjectString filepath(request[0]);
-    const int64_t millis = CObjectInt32OrInt64ToInt64(request[1]);
-    if (File::SetLastModified(filepath.CString(), millis)) {
-      return CObject::Null();
-    } else {
-      return CObject::NewOSError();
-    }
-  }
-  return CObject::IllegalArgumentError();
+  if ((request.Length() < 1) || !request[0]->IsIntptr()) {
+    return CObject::IllegalArgumentError();
+  }
+  Namespace* namespc = CObjectToNamespacePointer(request[0]);
+  RefCntReleaseScope<Namespace> rs(namespc);
+  if ((request.Length() != 3) ||
+      !request[1]->IsString() ||
+      !request[2]->IsInt32OrInt64()) {
+    return CObject::IllegalArgumentError();
+  }
+  CObjectString filepath(request[1]);
+  const int64_t millis = CObjectInt32OrInt64ToInt64(request[2]);
+  return File::SetLastModified(namespc, filepath.CString(), millis)
+         ? CObject::Null()
+         : CObject::NewOSError();
 }
 
 CObject* File::FlushRequest(const CObjectArray& request) {
-  if ((request.Length() == 1) && request[0]->IsIntptr()) {
-    File* file = CObjectToFilePointer(request[0]);
-    RefCntReleaseScope<File> rs(file);
-    if (!file->IsClosed()) {
-      if (file->Flush()) {
-        return CObject::True();
-      } else {
-        return CObject::NewOSError();
-      }
-    } else {
-      return CObject::FileClosedError();
-    }
-  }
-  return CObject::IllegalArgumentError();
+  if ((request.Length() < 1) || !request[0]->IsIntptr()) {
+    return CObject::IllegalArgumentError();
+  }
+  File* file = CObjectToFilePointer(request[0]);
+  RefCntReleaseScope<File> rs(file);
+  if (file->IsClosed()) {
+    return CObject::FileClosedError();
+  }
+  return file->Flush() ? CObject::True() : CObject::NewOSError();
 }
 
 CObject* File::ReadByteRequest(const CObjectArray& request) {
-  if ((request.Length() == 1) && request[0]->IsIntptr()) {
-    File* file = CObjectToFilePointer(request[0]);
-    RefCntReleaseScope<File> rs(file);
-    if (!file->IsClosed()) {
-      uint8_t buffer;
-      int64_t bytes_read = file->Read(reinterpret_cast<void*>(&buffer), 1);
-      if (bytes_read > 0) {
-        return new CObjectIntptr(CObject::NewIntptr(buffer));
-      } else if (bytes_read == 0) {
-        return new CObjectIntptr(CObject::NewIntptr(-1));
-      } else {
-        return CObject::NewOSError();
-      }
-    } else {
-      return CObject::FileClosedError();
-    }
-  }
-  return CObject::IllegalArgumentError();
+  if ((request.Length() < 1) || !request[0]->IsIntptr()) {
+    return CObject::IllegalArgumentError();
+  }
+  File* file = CObjectToFilePointer(request[0]);
+  RefCntReleaseScope<File> rs(file);
+  if (file->IsClosed()) {
+    return CObject::FileClosedError();
+  }
+  uint8_t buffer;
+  const int64_t bytes_read = file->Read(
+      reinterpret_cast<void*>(&buffer), 1);
+  if (bytes_read < 0) {
+    return CObject::NewOSError();
+  }
+  if (bytes_read == 0) {
+    return new CObjectIntptr(CObject::NewIntptr(-1));
+  }
+  return new CObjectIntptr(CObject::NewIntptr(buffer));
 }
 
 CObject* File::WriteByteRequest(const CObjectArray& request) {
-  if ((request.Length() >= 1) && request[0]->IsIntptr()) {
-    File* file = CObjectToFilePointer(request[0]);
-    RefCntReleaseScope<File> rs(file);
-    if ((request.Length() == 2) && request[1]->IsInt32OrInt64()) {
-      if (!file->IsClosed()) {
-        int64_t byte = CObjectInt32OrInt64ToInt64(request[1]);
-        uint8_t buffer = static_cast<uint8_t>(byte & 0xff);
-        bool success = file->WriteFully(reinterpret_cast<void*>(&buffer), 1);
-        if (success) {
-          return new CObjectInt64(CObject::NewInt64(1));
-        } else {
-          return CObject::NewOSError();
-        }
-      } else {
-        return CObject::FileClosedError();
-      }
-    } else {
-      return CObject::IllegalArgumentError();
-    }
-  }
-  return CObject::IllegalArgumentError();
+  if ((request.Length() < 1) || !request[0]->IsIntptr()) {
+    return CObject::IllegalArgumentError();
+  }
+  File* file = CObjectToFilePointer(request[0]);
+  RefCntReleaseScope<File> rs(file);
+  if ((request.Length() != 2) || !request[1]->IsInt32OrInt64()) {
+    return CObject::IllegalArgumentError();
+  }
+  if (file->IsClosed()) {
+    return CObject::FileClosedError();
+  }
+  const int64_t byte = CObjectInt32OrInt64ToInt64(request[1]);
+  uint8_t buffer = static_cast<uint8_t>(byte & 0xff);
+  return file->WriteFully(reinterpret_cast<void*>(&buffer), 1)
+         ? new CObjectInt64(CObject::NewInt64(1))
+         : CObject::NewOSError();
 }
 
 CObject* File::ReadRequest(const CObjectArray& request) {
-  if ((request.Length() >= 1) && request[0]->IsIntptr()) {
-    File* file = CObjectToFilePointer(request[0]);
-    RefCntReleaseScope<File> rs(file);
-    if ((request.Length() == 2) && request[1]->IsInt32OrInt64()) {
-      if (!file->IsClosed()) {
-        int64_t length = CObjectInt32OrInt64ToInt64(request[1]);
-        Dart_CObject* io_buffer = CObject::NewIOBuffer(length);
-        ASSERT(io_buffer != NULL);
-        uint8_t* data = io_buffer->value.as_external_typed_data.data;
-        int64_t bytes_read = file->Read(data, length);
-        if (bytes_read >= 0) {
-          CObjectExternalUint8Array* external_array =
-              new CObjectExternalUint8Array(io_buffer);
-          external_array->SetLength(bytes_read);
-          CObjectArray* result = new CObjectArray(CObject::NewArray(2));
-          result->SetAt(0, new CObjectIntptr(CObject::NewInt32(0)));
-          result->SetAt(1, external_array);
-          return result;
-        } else {
-          CObject::FreeIOBufferData(io_buffer);
-          return CObject::NewOSError();
-        }
-      } else {
-        return CObject::FileClosedError();
-      }
-    } else {
-      return CObject::IllegalArgumentError();
-    }
-  }
-  return CObject::IllegalArgumentError();
+  if ((request.Length() < 1) || !request[0]->IsIntptr()) {
+    return CObject::IllegalArgumentError();
+  }
+  File* file = CObjectToFilePointer(request[0]);
+  RefCntReleaseScope<File> rs(file);
+  if ((request.Length() != 2) || !request[1]->IsInt32OrInt64()) {
+    return CObject::IllegalArgumentError();
+  }
+  if (file->IsClosed()) {
+    return CObject::FileClosedError();
+  }
+  const int64_t length = CObjectInt32OrInt64ToInt64(request[1]);
+  Dart_CObject* io_buffer = CObject::NewIOBuffer(length);
+  ASSERT(io_buffer != NULL);
+  uint8_t* data = io_buffer->value.as_external_typed_data.data;
+  const int64_t bytes_read = file->Read(data, length);
+  if (bytes_read < 0) {
+    CObject::FreeIOBufferData(io_buffer);
+    return CObject::NewOSError();
+  }
+  CObjectExternalUint8Array* external_array =
+      new CObjectExternalUint8Array(io_buffer);
+  external_array->SetLength(bytes_read);
+  CObjectArray* result = new CObjectArray(CObject::NewArray(2));
+  result->SetAt(0, new CObjectIntptr(CObject::NewInt32(0)));
+  result->SetAt(1, external_array);
+  return result;
 }
 
 CObject* File::ReadIntoRequest(const CObjectArray& request) {
-  if ((request.Length() >= 1) && request[0]->IsIntptr()) {
-    File* file = CObjectToFilePointer(request[0]);
-    RefCntReleaseScope<File> rs(file);
-    if ((request.Length() == 2) && request[1]->IsInt32OrInt64()) {
-      if (!file->IsClosed()) {
-        int64_t length = CObjectInt32OrInt64ToInt64(request[1]);
-        Dart_CObject* io_buffer = CObject::NewIOBuffer(length);
-        ASSERT(io_buffer != NULL);
-        uint8_t* data = io_buffer->value.as_external_typed_data.data;
-        int64_t bytes_read = file->Read(data, length);
-        if (bytes_read >= 0) {
-          CObjectExternalUint8Array* external_array =
-              new CObjectExternalUint8Array(io_buffer);
-          external_array->SetLength(bytes_read);
-          CObjectArray* result = new CObjectArray(CObject::NewArray(3));
-          result->SetAt(0, new CObjectIntptr(CObject::NewInt32(0)));
-          result->SetAt(1, new CObjectInt64(CObject::NewInt64(bytes_read)));
-          result->SetAt(2, external_array);
-          return result;
-        } else {
-          CObject::FreeIOBufferData(io_buffer);
-          return CObject::NewOSError();
-        }
-      } else {
-        return CObject::FileClosedError();
-      }
-    } else {
-      return CObject::IllegalArgumentError();
-    }
-  }
-  return CObject::IllegalArgumentError();
+  if ((request.Length() < 1) || !request[0]->IsIntptr()) {
+    return CObject::IllegalArgumentError();
+  }
+  File* file = CObjectToFilePointer(request[0]);
+  RefCntReleaseScope<File> rs(file);
+  if ((request.Length() != 2) || !request[1]->IsInt32OrInt64()) {
+    return CObject::IllegalArgumentError();
+  }
+  if (file->IsClosed()) {
+    return CObject::FileClosedError();
+  }
+  const int64_t length = CObjectInt32OrInt64ToInt64(request[1]);
+  Dart_CObject* io_buffer = CObject::NewIOBuffer(length);
+  ASSERT(io_buffer != NULL);
+  uint8_t* data = io_buffer->value.as_external_typed_data.data;
+  const int64_t bytes_read = file->Read(data, length);
+  if (bytes_read < 0) {
+    CObject::FreeIOBufferData(io_buffer);
+    return CObject::NewOSError();
+  }
+  CObjectExternalUint8Array* external_array =
+      new CObjectExternalUint8Array(io_buffer);
+  external_array->SetLength(bytes_read);
+  CObjectArray* result = new CObjectArray(CObject::NewArray(3));
+  result->SetAt(0, new CObjectIntptr(CObject::NewInt32(0)));
+  result->SetAt(1, new CObjectInt64(CObject::NewInt64(bytes_read)));
+  result->SetAt(2, external_array);
+  return result;
 }
 
 static int SizeInBytes(Dart_TypedData_Type type) {
   switch (type) {
     case Dart_TypedData_kInt8:
     case Dart_TypedData_kUint8:
     case Dart_TypedData_kUint8Clamped:
       return 1;
     case Dart_TypedData_kInt16:
     case Dart_TypedData_kUint16:
       return 2;
     case Dart_TypedData_kInt32:
     case Dart_TypedData_kUint32:
     case Dart_TypedData_kFloat32:
       return 4;
     case Dart_TypedData_kInt64:
     case Dart_TypedData_kUint64:
     case Dart_TypedData_kFloat64:
       return 8;
     default:
       break;
   }
   UNREACHABLE();
   return -1;
 }
 
 CObject* File::WriteFromRequest(const CObjectArray& request) {
-  if ((request.Length() >= 1) && request[0]->IsIntptr()) {
-    File* file = CObjectToFilePointer(request[0]);
-    RefCntReleaseScope<File> rs(file);
-    if ((request.Length() == 4) &&
-        (request[1]->IsTypedData() || request[1]->IsArray()) &&
-        request[2]->IsInt32OrInt64() && request[3]->IsInt32OrInt64()) {
-      if (!file->IsClosed()) {
-        int64_t start = CObjectInt32OrInt64ToInt64(request[2]);
-        int64_t end = CObjectInt32OrInt64ToInt64(request[3]);
-        int64_t length = end - start;
-        uint8_t* buffer_start;
-        if (request[1]->IsTypedData()) {
-          CObjectTypedData typed_data(request[1]);
-          start = start * SizeInBytes(typed_data.Type());
-          length = length * SizeInBytes(typed_data.Type());
-          buffer_start = typed_data.Buffer() + start;
-        } else {
-          CObjectArray array(request[1]);
-          buffer_start = Dart_ScopeAllocate(length);
-          for (int i = 0; i < length; i++) {
-            if (array[i + start]->IsInt32OrInt64()) {
-              int64_t value = CObjectInt32OrInt64ToInt64(array[i + start]);
-              buffer_start[i] = static_cast<uint8_t>(value & 0xFF);
-            } else {
-              // Unsupported type.
-              return CObject::IllegalArgumentError();
-            }
-          }
-          start = 0;
-        }
-        bool success =
-            file->WriteFully(reinterpret_cast<void*>(buffer_start), length);
-        if (success) {
-          return new CObjectInt64(CObject::NewInt64(length));
-        } else {
-          return CObject::NewOSError();
-        }
+  if ((request.Length() < 1) || !request[0]->IsIntptr()) {
+    return CObject::IllegalArgumentError();
+  }
+  File* file = CObjectToFilePointer(request[0]);
+  RefCntReleaseScope<File> rs(file);
+  if ((request.Length() != 4) ||
+      (!request[1]->IsTypedData() && !request[1]->IsArray()) ||
+      !request[2]->IsInt32OrInt64() || !request[3]->IsInt32OrInt64()) {
+    return CObject::IllegalArgumentError();
+  }
+  if (file->IsClosed()) {
+    return CObject::FileClosedError();
+  }
+  int64_t start = CObjectInt32OrInt64ToInt64(request[2]);
+  int64_t end = CObjectInt32OrInt64ToInt64(request[3]);
+  int64_t length = end - start;
+  uint8_t* buffer_start;
+  if (request[1]->IsTypedData()) {
+    CObjectTypedData typed_data(request[1]);
+    start = start * SizeInBytes(typed_data.Type());
+    length = length * SizeInBytes(typed_data.Type());
+    buffer_start = typed_data.Buffer() + start;
+  } else {
+    CObjectArray array(request[1]);
+    buffer_start = Dart_ScopeAllocate(length);
+    for (int i = 0; i < length; i++) {
+      if (array[i + start]->IsInt32OrInt64()) {
+        int64_t value = CObjectInt32OrInt64ToInt64(array[i + start]);
+        buffer_start[i] = static_cast<uint8_t>(value & 0xFF);
       } else {
-        return CObject::FileClosedError();
+        // Unsupported type.
+        return CObject::IllegalArgumentError();
       }
-    } else {
-      return CObject::IllegalArgumentError();
     }
+    start = 0;
   }
-  return CObject::IllegalArgumentError();
+  return file->WriteFully(reinterpret_cast<void*>(buffer_start), length)
+         ? new CObjectInt64(CObject::NewInt64(length))
+         : CObject::NewOSError();
 }
 
 CObject* File::CreateLinkRequest(const CObjectArray& request) {
-  if ((request.Length() != 2) || !request[0]->IsString() ||
-      !request[1]->IsString()) {
+  if ((request.Length() != 3) || !request[0]->IsIntptr()) {
     return CObject::IllegalArgumentError();
   }
-  CObjectString link_name(request[0]);
-  CObjectString target_name(request[1]);
-  if (File::CreateLink(link_name.CString(), target_name.CString())) {
-    return CObject::True();
-  } else {
-    return CObject::NewOSError();
+  Namespace* namespc = CObjectToNamespacePointer(request[0]);
+  RefCntReleaseScope<Namespace> rs(namespc);
+  if (!request[1]->IsString() || !request[2]->IsString()) {
+    return CObject::IllegalArgumentError();
   }
+  CObjectString link_name(request[1]);
+  CObjectString target_name(request[2]);
+  return File::CreateLink(namespc, link_name.CString(), target_name.CString())
+         ? CObject::True()
+         : CObject::NewOSError();
 }
 
 CObject* File::DeleteLinkRequest(const CObjectArray& request) {
-  if ((request.Length() == 1) && request[0]->IsString()) {
-    CObjectString link_path(request[0]);
-    bool result = File::DeleteLink(link_path.CString());
-    if (result) {
-      return CObject::True();
-    } else {
-      return CObject::NewOSError();
-    }
+  if ((request.Length() != 2) || !request[0]->IsIntptr()) {
+    return CObject::IllegalArgumentError();
   }
-  return CObject::IllegalArgumentError();
+  Namespace* namespc = CObjectToNamespacePointer(request[0]);
+  RefCntReleaseScope<Namespace> rs(namespc);
+  if (!request[1]->IsString()) {
+    return CObject::IllegalArgumentError();
+  }
+  CObjectString link_path(request[1]);
+  return File::DeleteLink(namespc, link_path.CString()) ? CObject::True()
+                                                        : CObject::NewOSError();
 }
 
 CObject* File::RenameLinkRequest(const CObjectArray& request) {
-  if ((request.Length() == 2) && request[0]->IsString() &&
-      request[1]->IsString()) {
-    CObjectString old_path(request[0]);
-    CObjectString new_path(request[1]);
-    bool completed = File::RenameLink(old_path.CString(), new_path.CString());
-    if (completed) {
-      return CObject::True();
-    }
-    return CObject::NewOSError();
+  if ((request.Length() != 3) || !request[0]->IsIntptr()) {
+    return CObject::IllegalArgumentError();
   }
-  return CObject::IllegalArgumentError();
+  Namespace* namespc = CObjectToNamespacePointer(request[0]);
+  RefCntReleaseScope<Namespace> rs(namespc);
+  if (!request[1]->IsString() || !request[2]->IsString()) {
+    return CObject::IllegalArgumentError();
+  }
+  CObjectString old_path(request[1]);
+  CObjectString new_path(request[2]);
+  return File::RenameLink(namespc, old_path.CString(), new_path.CString())
+         ? CObject::True()
+         : CObject::NewOSError();
 }
 
 CObject* File::LinkTargetRequest(const CObjectArray& request) {
-  if ((request.Length() == 1) && request[0]->IsString()) {
-    CObjectString link_path(request[0]);
-    const char* target = File::LinkTarget(link_path.CString());
-    if (target != NULL) {
-      CObject* result = new CObjectString(CObject::NewString(target));
-      return result;
-    } else {
-      return CObject::NewOSError();
-    }
+  if ((request.Length() != 2) || !request[0]->IsIntptr()) {
+    return CObject::IllegalArgumentError();
   }
-  return CObject::IllegalArgumentError();
+  Namespace* namespc = CObjectToNamespacePointer(request[0]);
+  RefCntReleaseScope<Namespace> rs(namespc);
+  if (!request[1]->IsString()) {
+    return CObject::IllegalArgumentError();
+  }
+  CObjectString link_path(request[1]);
+  const char* target = File::LinkTarget(namespc, link_path.CString());
+  if (target == NULL) {
+    return CObject::NewOSError();
+  }
+  return new CObjectString(CObject::NewString(target));
 }
 
 CObject* File::TypeRequest(const CObjectArray& request) {
-  if ((request.Length() == 2) && request[0]->IsString() &&
-      request[1]->IsBool()) {
-    CObjectString path(request[0]);
-    CObjectBool follow_links(request[1]);
-    File::Type type = File::GetType(path.CString(), follow_links.Value());
-    return new CObjectInt32(CObject::NewInt32(type));
+  if ((request.Length() != 3) || !request[0]->IsIntptr()) {
+    return CObject::IllegalArgumentError();
   }
-  return CObject::IllegalArgumentError();
+  Namespace* namespc = CObjectToNamespacePointer(request[0]);
+  RefCntReleaseScope<Namespace> rs(namespc);
+  if (!request[1]->IsString() || !request[2]->IsBool()) {
+    return CObject::IllegalArgumentError();
+  }
+  CObjectString path(request[1]);
+  CObjectBool follow_links(request[2]);
+  File::Type type = File::GetType(
+      namespc, path.CString(), follow_links.Value());
+  return new CObjectInt32(CObject::NewInt32(type));
 }
 
 CObject* File::IdenticalRequest(const CObjectArray& request) {
-  if ((request.Length() == 2) && request[0]->IsString() &&
-      request[1]->IsString()) {
-    CObjectString path1(request[0]);
-    CObjectString path2(request[1]);
-    File::Identical result =
-        File::AreIdentical(path1.CString(), path2.CString());
-    if (result == File::kError) {
-      return CObject::NewOSError();
-    } else if (result == File::kIdentical) {
-      return CObject::True();
-    } else {
-      return CObject::False();
-    }
+  if ((request.Length() != 3) || !request[0]->IsIntptr()) {
+    return CObject::IllegalArgumentError();
   }
-  return CObject::IllegalArgumentError();
+  Namespace* namespc = CObjectToNamespacePointer(request[0]);
+  RefCntReleaseScope<Namespace> rs(namespc);
+  if (!request[1]->IsString() || !request[2]->IsString()) {
+    return CObject::IllegalArgumentError();
+  }
+  CObjectString path1(request[1]);
+  CObjectString path2(request[2]);
+  File::Identical result = File::AreIdentical(
+      namespc, path1.CString(), path2.CString());
+  if (result == File::kError) {
+    return CObject::NewOSError();
+  }
+  return (result == File::kIdentical) ? CObject::True() : CObject::False();
 }
 
 CObject* File::StatRequest(const CObjectArray& request) {
-  if ((request.Length() == 1) && request[0]->IsString()) {
-    int64_t data[File::kStatSize];
-    CObjectString path(request[0]);
-    File::Stat(path.CString(), data);
-    if (data[File::kType] == File::kDoesNotExist) {
-      return CObject::NewOSError();
-    }
-    CObjectArray* result = new CObjectArray(CObject::NewArray(File::kStatSize));
-    for (int i = 0; i < File::kStatSize; ++i) {
-      result->SetAt(i, new CObjectInt64(CObject::NewInt64(data[i])));
-    }
-    CObjectArray* wrapper = new CObjectArray(CObject::NewArray(2));
-    wrapper->SetAt(0, new CObjectInt32(CObject::NewInt32(CObject::kSuccess)));
-    wrapper->SetAt(1, result);
-    return wrapper;
+  if ((request.Length() < 1) || !request[0]->IsIntptr()) {
+    return CObject::IllegalArgumentError();
   }
-  return CObject::IllegalArgumentError();
+  Namespace* namespc = CObjectToNamespacePointer(request[0]);
+  RefCntReleaseScope<Namespace> rs(namespc);
+  if ((request.Length() != 2) || !request[1]->IsString()) {
+    return CObject::IllegalArgumentError();
+  }
+  int64_t data[File::kStatSize];
+  CObjectString path(request[1]);
+  File::Stat(namespc, path.CString(), data);
+  if (data[File::kType] == File::kDoesNotExist) {
+    return CObject::NewOSError();
+  }
+  CObjectArray* result = new CObjectArray(CObject::NewArray(File::kStatSize));
+  for (int i = 0; i < File::kStatSize; ++i) {
+    result->SetAt(i, new CObjectInt64(CObject::NewInt64(data[i])));
+  }
+  CObjectArray* wrapper = new CObjectArray(CObject::NewArray(2));
+  wrapper->SetAt(0, new CObjectInt32(CObject::NewInt32(CObject::kSuccess)));
+  wrapper->SetAt(1, result);
+  return wrapper;
 }
 
 CObject* File::LockRequest(const CObjectArray& request) {
-  if ((request.Length() >= 1) && request[0]->IsIntptr()) {
-    File* file = CObjectToFilePointer(request[0]);
-    RefCntReleaseScope<File> rs(file);
-    if ((request.Length() == 4) && request[1]->IsInt32OrInt64() &&
-        request[2]->IsInt32OrInt64() && request[3]->IsInt32OrInt64()) {
-      if (!file->IsClosed()) {
-        int64_t lock = CObjectInt32OrInt64ToInt64(request[1]);
-        int64_t start = CObjectInt32OrInt64ToInt64(request[2]);
-        int64_t end = CObjectInt32OrInt64ToInt64(request[3]);
-        if (file->Lock(static_cast<File::LockType>(lock), start, end)) {
-          return CObject::True();
-        } else {
-          return CObject::NewOSError();
-        }
-      } else {
-        return CObject::FileClosedError();
-      }
-    } else {
-      return CObject::IllegalArgumentError();
-    }
+  if ((request.Length() < 1) || !request[0]->IsIntptr()) {
+    return CObject::IllegalArgumentError();
   }
-  return CObject::IllegalArgumentError();
+  File* file = CObjectToFilePointer(request[0]);
+  RefCntReleaseScope<File> rs(file);
+  if ((request.Length() != 4) || !request[1]->IsInt32OrInt64() ||
+      !request[2]->IsInt32OrInt64() || !request[3]->IsInt32OrInt64()) {
+    return CObject::IllegalArgumentError();
+  }
+  if (file->IsClosed()) {
+    return CObject::FileClosedError();
+  }
+  const int64_t lock = CObjectInt32OrInt64ToInt64(request[1]);
+  const int64_t start = CObjectInt32OrInt64ToInt64(request[2]);
+  const int64_t end = CObjectInt32OrInt64ToInt64(request[3]);
+  return file->Lock(static_cast<File::LockType>(lock), start, end)
+        ? CObject::True()
+        : CObject::NewOSError();
 }
 
 }  // namespace bin
 }  // namespace dart