gecko-dev/dom/cache/QuotaClient.h

63 строки
2.3 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef mozilla_dom_cache_QuotaClient_h
#define mozilla_dom_cache_QuotaClient_h
#include "mozilla/Attributes.h"
#include "mozilla/dom/cache/Types.h"
#include "mozilla/dom/quota/Client.h"
namespace mozilla {
namespace dom {
namespace cache {
already_AddRefed<quota::Client>
CreateQuotaClient();
/**
* The following functions are used to access the directory padding file. The
* directory padding file lives in DOM Cache base directory
* (e.g. foo.com/cache/.padding). It is used to keep the current overall padding
* size for an origin, so that the QuotaManager doesn't need to access the
* database when getting quota clients' usage.
*
* For the directory padding file, it's only accessed on Quota IO thread
* (for getting current usage) and Cache IO threads (for tracking padding size
* change). Besides, the padding file is protected by a mutex lock held by
* CacheQuotaClient.
*
* Each padding file should only take 8 bytes (int64_t) to record the overall
* padding size. Besides, we use the temporary padding file to indicate if the
* previous action is completed successfully. If the temporary file exists, it
* represents that the previous action is failed and the content of padding file
* cannot be trusted, and we need to restore the padding file from the database.
*/
/**
* Note: The aCommitHook argument will be invoked while a lock is held. Callers
* should be careful not to pass a hook that might lock on something else and
* trigger a deadlock.
*/
template<typename Callable>
nsresult
MaybeUpdatePaddingFile(nsIFile* aBaseDir,
mozIStorageConnection* aConn,
const int64_t aIncreaseSize,
const int64_t aDecreaseSize,
Callable aCommitHook);
nsresult
RestorePaddingFile(nsIFile* aBaseDir, mozIStorageConnection* aConn);
nsresult
WipePaddingFile(const QuotaInfo& aQuotaInfo, nsIFile* aBaseDir);
} // namespace cache
} // namespace dom
} // namespace mozilla
#endif // mozilla_dom_cache_QuotaClient_h