// 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 #include #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 { 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 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; 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, 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_