Pepper: Ensure FileIO host cleans up before FileSystem host destructs.

ppapi/proxy/file_io_resource.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 "ppapi/proxy/file_io_resource.h"
 
 #include "base/bind.h"
 #include "base/task_runner_util.h"
 #include "ipc/ipc_message.h"
 #include "ppapi/c/pp_errors.h"
 #include "ppapi/proxy/ppapi_messages.h"
 #include "ppapi/shared_impl/array_writer.h"
 #include "ppapi/shared_impl/file_ref_create_info.h"
 #include "ppapi/shared_impl/file_system_util.h"
 #include "ppapi/shared_impl/file_type_conversion.h"
 #include "ppapi/shared_impl/ppapi_globals.h"
 #include "ppapi/shared_impl/proxy_lock.h"
 #include "ppapi/shared_impl/resource_tracker.h"
 #include "ppapi/thunk/enter.h"
 #include "ppapi/thunk/ppb_file_ref_api.h"
+#include "ppapi/thunk/ppb_file_system_api.h"
 
 using ppapi::thunk::EnterResourceNoLock;
 using ppapi::thunk::PPB_FileIO_API;
 using ppapi::thunk::PPB_FileRef_API;
+using ppapi::thunk::PPB_FileSystem_API;
 
 namespace {
 
 // We must allocate a buffer sized according to the request of the plugin. To
 // reduce the chance of out-of-memory errors, we cap the read and write size to
 // 32MB. This is OK since the API specifies that it may perform a partial read
 // or write.
 static const int32_t kMaxReadWriteSize = 32 * 1024 * 1024;  // 32MB
 
 // An adapter to let Read() share the same implementation with ReadToArray().
@@ skipping 52 matching lines @@
 FileIOResource::~FileIOResource() {
 }
 
 PPB_FileIO_API* FileIOResource::AsPPB_FileIO_API() {
   return this;
 }
 
 int32_t FileIOResource::Open(PP_Resource file_ref,
                              int32_t open_flags,
                              scoped_refptr<TrackedCallback> callback) {
-  EnterResourceNoLock<PPB_FileRef_API> enter(file_ref, true);
-  if (enter.failed())
+  EnterResourceNoLock<PPB_FileRef_API> enter_file_ref(file_ref, true);
+  if (enter_file_ref.failed())
     return PP_ERROR_BADRESOURCE;
 
-  PPB_FileRef_API* file_ref_api = enter.object();
+  PPB_FileRef_API* file_ref_api = enter_file_ref.object();
   const FileRefCreateInfo& create_info = file_ref_api->GetCreateInfo();
   if (!FileSystemTypeIsValid(create_info.file_system_type)) {
     NOTREACHED();
     return PP_ERROR_FAILED;
   }
-
   int32_t rv = state_manager_.CheckOperationState(
       FileIOStateManager::OPERATION_EXCLUSIVE, false);
   if (rv != PP_OK)
     return rv;
 
   file_system_type_ = create_info.file_system_type;
-  // Keep the FileSystem host alive by taking a reference to its resource. The
-  // FileIO host uses the FileSystem host for running tasks.
-  file_system_resource_ = create_info.file_system_plugin_resource;
+
+  if (create_info.file_system_plugin_resource) {
+    EnterResourceNoLock<PPB_FileSystem_API> enter_file_system(
+        create_info.file_system_plugin_resource, true);
+    if (enter_file_system.failed())
+      return PP_ERROR_FAILED;
+    // Take a reference on the FileSystem resource. The FileIO host uses the
+    // FileSystem host for running tasks and checking quota.
+    file_system_resource_ = enter_file_system.resource();
+  }
 
   // Take a reference on the FileRef resource while we're opening the file; we
   // don't want the plugin destroying it during the Open operation.
-  file_ref_ = enter.resource();
+  file_ref_ = enter_file_ref.resource();
 
   Call<PpapiPluginMsg_FileIO_OpenReply>(BROWSER,
       PpapiHostMsg_FileIO_Open(
           file_ref,
           open_flags),
       base::Bind(&FileIOResource::OnPluginMsgOpenFileComplete, this,
                  callback));
 
   state_manager_.SetPendingOperation(FileIOStateManager::OPERATION_EXCLUSIVE);
   return PP_OK_COMPLETIONPENDING;
@@ skipping 326 matching lines @@
   *output_handle = IPC::PlatformFileForTransitToPlatformFile(transit_file);
 
   // End this operation now, so the user's callback can execute another FileIO
   // operation, assuming there are no other pending operations.
   state_manager_.SetOperationFinished();
   callback->Run(result);
 }
 
 }  // namespace proxy
 }  // namespace ppapi