Make Isolated file system writable only if it is configured so

webkit/fileapi/isolated_mount_point_provider.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "webkit/fileapi/isolated_mount_point_provider.h"
 
 #include <string>
 
 #include "base/bind.h"
 #include "base/file_path.h"
 #include "base/logging.h"
 #include "base/message_loop_proxy.h"
 #include "base/sequenced_task_runner.h"
 #include "googleurl/src/gurl.h"
 #include "webkit/blob/local_file_stream_reader.h"
 #include "webkit/fileapi/file_system_callback_dispatcher.h"
 #include "webkit/fileapi/file_system_context.h"
 #include "webkit/fileapi/file_system_file_stream_reader.h"
 #include "webkit/fileapi/file_system_operation.h"
 #include "webkit/fileapi/file_system_types.h"
 #include "webkit/fileapi/file_system_util.h"
 #include "webkit/fileapi/isolated_context.h"
 #include "webkit/fileapi/isolated_file_util.h"
 #include "webkit/fileapi/local_file_stream_writer.h"
 #include "webkit/fileapi/native_file_util.h"
 
 namespace fileapi {
 
+namespace {
+
+IsolatedContext* isolated_context() {
+  return IsolatedContext::GetInstance();
+}
+
+FilePath GetPathFromURL(const GURL& url, bool for_writing) {
+  GURL origin_url;
+  FileSystemType file_system_type = kFileSystemTypeUnknown;
+  FilePath virtual_path;
+  if (!CrackFileSystemURL(url, &origin_url, &file_system_type, &virtual_path))
+    return FilePath();
+  std::string fsid;
+  FilePath path;
+  if (!isolated_context()->CrackIsolatedPath(virtual_path, &fsid, NULL, &path))
+    return FilePath();
+  if (for_writing && !isolated_context()->IsWritable(fsid))
+    return FilePath();
+  return path;
+}
+
+}  // namespace
+
 IsolatedMountPointProvider::IsolatedMountPointProvider()
     : isolated_file_util_(new IsolatedFileUtil()) {
 }
 
 IsolatedMountPointProvider::~IsolatedMountPointProvider() {
 }
 
 void IsolatedMountPointProvider::ValidateFileSystemRoot(
     const GURL& origin_url,
     FileSystemType type,
@@ skipping 61 matching lines @@
     const FilePath& virtual_path,
     FileSystemContext* context) const {
   return new FileSystemOperation(context);
 }
 
 webkit_blob::FileStreamReader*
 IsolatedMountPointProvider::CreateFileStreamReader(
     const GURL& url,
     int64 offset,
     FileSystemContext* context) const {
-  FilePath path = GetPathFromURL(url);
+  FilePath path = GetPathFromURL(url, false);
   return path.empty() ? NULL : new webkit_blob::LocalFileStreamReader(
       context->file_task_runner(), path, offset, base::Time());
 }
 
 FileStreamWriter* IsolatedMountPointProvider::CreateFileStreamWriter(
     const GURL& url,
     int64 offset,
     FileSystemContext* context) const {
-  FilePath path = GetPathFromURL(url);
+  FilePath path = GetPathFromURL(url, true);
   return path.empty() ? NULL : new LocalFileStreamWriter(path, offset);
 }
 
 FileSystemQuotaUtil* IsolatedMountPointProvider::GetQuotaUtil() {
   // No quota support.
   return NULL;
 }
 
-IsolatedContext* IsolatedMountPointProvider::isolated_context() const {
-  return IsolatedContext::GetInstance();
-}
-
-FilePath IsolatedMountPointProvider::GetPathFromURL(const GURL& url) const {
-  GURL origin_url;
-  FileSystemType file_system_type = kFileSystemTypeUnknown;
-  FilePath virtual_path;
-  if (!CrackFileSystemURL(url, &origin_url, &file_system_type, &virtual_path))
-    return FilePath();
-  std::string fsid;
-  FilePath path;
-  if (!isolated_context()->CrackIsolatedPath(virtual_path, &fsid, NULL, &path))
-    return FilePath();
-  return path;
-}
-
 }  // namespace fileapi