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- // Copyright (c) 2017 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 NET_DISK_CACHE_BACKEND_CLEANUP_TRACKER_H_
- #define NET_DISK_CACHE_BACKEND_CLEANUP_TRACKER_H_
- #include <utility>
- #include <vector>
- #include "base/callback.h"
- #include "base/files/file_path.h"
- #include "base/memory/ref_counted.h"
- #include "base/sequence_checker.h"
- #include "net/base/net_export.h"
- namespace base {
- class SequencedTaskRunner;
- } // namespace base
- namespace disk_cache {
- // Internal helper used to sequence cleanup and reuse of cache directories.
- // One of these is created before each backend, and is kept alive till both
- // the backend is destroyed and all of its work is done by its refcount,
- // which keeps track of outstanding work. That refcount is expected to only be
- // updated from the I/O thread or its equivalent.
- class NET_EXPORT_PRIVATE BackendCleanupTracker
- : public base::RefCounted<BackendCleanupTracker> {
- public:
- // Either returns a fresh cleanup tracker for |path| if none exists, or
- // will eventually post |retry_closure| to the calling thread,
- // and return null.
- static scoped_refptr<BackendCleanupTracker> TryCreate(
- const base::FilePath& path,
- base::OnceClosure retry_closure);
- BackendCleanupTracker(const BackendCleanupTracker&) = delete;
- BackendCleanupTracker& operator=(const BackendCleanupTracker&) = delete;
- // Register a callback to be posted after all the work of associated
- // context is complete (which will result in destruction of this context).
- // Should only be called by owner, on its I/O-thread-like execution context,
- // and will in turn eventually post |cb| there.
- void AddPostCleanupCallback(base::OnceClosure cb);
- private:
- friend class base::RefCounted<BackendCleanupTracker>;
- explicit BackendCleanupTracker(const base::FilePath& path);
- ~BackendCleanupTracker();
- void AddPostCleanupCallbackImpl(base::OnceClosure cb);
- base::FilePath path_;
- // Since it's possible that a different thread may want to create a
- // cache for a reused path, we keep track of runners contexts of
- // post-cleanup callbacks.
- std::vector<
- std::pair<scoped_refptr<base::SequencedTaskRunner>, base::OnceClosure>>
- post_cleanup_cbs_;
- // We expect only TryMakeContext to be multithreaded, everything
- // else should be sequenced.
- SEQUENCE_CHECKER(seq_checker_);
- };
- } // namespace disk_cache
- #endif // NET_DISK_CACHE_BACKEND_CLEANUP_TRACKER_H_
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