Pepper quota support

webkit/plugins/ppapi/quota_file_io.h

+// Copyright (c) 2011 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.
+
+#ifndef WEBKIT_PLUGINS_PPAPI_QUOTA_FILE_IO_H_
+#define WEBKIT_PLUGINS_PPAPI_QUOTA_FILE_IO_H_
+
+#include <deque>
+
+#include "base/file_util_proxy.h"
+#include "base/memory/scoped_callback_factory.h"
+#include "base/platform_file.h"
+#include "googleurl/src/gurl.h"
+#include "ppapi/c/pp_file_info.h"
+#include "webkit/quota/quota_types.h"
+
+namespace webkit {
+namespace ppapi {
+
+class PluginInstance;
+
+// This class is created per PPB_FileIO_Impl instance and provides
+// write operations for quota-managed files (i.e. files of
+// PP_FILESYSTEMTYPE_LOCAL{PERSISTENT,TEMPORARY}).
+class QuotaFileIO {
+ public:
+  typedef base::FileUtilProxy::WriteCallback WriteCallback;
+  typedef base::FileUtilProxy::StatusCallback StatusCallback;
+
+  QuotaFileIO(PluginInstance* instance,
+              base::PlatformFile file,
+              const GURL& path_url,
+              PP_FileSystemType type);
+  ~QuotaFileIO();
+
+  bool Write(int64_t offset,

[yzshen1, 2011/07/27 18:26:08]

1) Please comment that if returns false the callback won't be run.
2) It seems the all pending callbacks won't be run when this object is deleted,
right? Please also comment that.
3) If you want to keep the promise that all WriteCallbacks will be run in the
same order as calls to QuotaFileIO::Write, please also comment it.

[kinuko, 2011/07/28 14:11:00]

Done.

+             const char* buffer,
+             int32_t bytes_to_write,
+             WriteCallback* callback);
+  bool SetLength(int64_t length, StatusCallback* callback);
+  bool WillWrite(int64_t offset,
+                 int32_t bytes_to_write,
+                 WriteCallback* callback);
+  bool WillSetLength(int64_t length, StatusCallback* callback);
+
+ private:
+  class PendingOperationBase;
+  class WriteOperation;
+  class SetLengthOperation;
+
+  bool CheckIfExceedsQuota(int64_t new_file_size) const;
+  void WillUpdate();
+  void DidWrite(WriteOperation* op, int64_t written_offset_end);
+  void DidSetLength(base::PlatformFileError error, int64_t new_file_size);
+
+  bool RegisterOperationForQuotaChecks(PendingOperationBase* op);
+  void DidQueryInfoForQuota(base::PlatformFileError error_code,
+                            const base::PlatformFileInfo& file_info);
+  void DidQueryAvailableSpace(int64_t avail_space);
+  void DidQueryForQuotaCheck();
+
+  // The plugin instance that owns this (via PPB_FileIO_Impl).
+  PluginInstance* instance_;
+
+  // The file information associated to this instance.
+  base::PlatformFile file_;
+  GURL file_url_;
+  quota::StorageType storage_type_;
+
+  // Operations waiting for a quota check to finish.
+  std::deque<PendingOperationBase*> pending_operations_;

[yzshen1, 2011/07/27 18:26:08]

All you use are *queue* operations. Why to change it to deque?

[kinuko, 2011/07/28 14:11:00]

I wanted to use methods like size(), begin() and end() which are not supported
by std:queue.  Also in the new code I use iterator which queue doesn't support
either.

[yzshen1, 2011/07/28 17:40:52]

Okay. :)

On 2011/07/28 14:11:00, kinuko wrote:

+
+  // Operations queued to dispatch the callbacks.
+  std::deque<PendingOperationBase*> pending_callbacks_;

[yzshen1, 2011/07/27 18:26:08]

It seems to me that you don't need two queues:
you always keep them in |pending_operations_|, and only when
inflight_operations_ == 0, you run all callbacks in order and remove all entries
in that queue.

Am I missing anything?

[kinuko, 2011/07/28 14:11:00]

That looks true.  Removed.

+
+  // Valid only while there're pending quota checks.
+  int64_t cached_file_size_;
+  int64_t cached_available_space_;
+
+  // Quota-related queries and errors occured during inflight quota checks.
+  int outstanding_quota_queries_;
+  int outstanding_errors_;
+
+  // For parallel writes bookkeeping.
+  int64_t max_written_offset_;
+  int inflight_operations_;
+
+  base::ScopedCallbackFactory<QuotaFileIO> callback_factory_;
+  DISALLOW_COPY_AND_ASSIGN(QuotaFileIO);
+};
+
+}  // namespace ppapi
+}  // namespace webkit
+
+#endif  // WEBKIT_PLUGINS_PPAPI_QUOTA_FILE_IO_H_