| // 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. |
| |
| // See net/disk_cache/disk_cache.h for the public interface of the cache. |
| |
| #ifndef NET_DISK_CACHE_MEMORY_MEM_BACKEND_IMPL_H_ |
| #define NET_DISK_CACHE_MEMORY_MEM_BACKEND_IMPL_H_ |
| |
| #include <stdint.h> |
| |
| #include <string> |
| #include <unordered_map> |
| |
| #include "base/callback_forward.h" |
| #include "base/compiler_specific.h" |
| #include "base/containers/linked_list.h" |
| #include "base/macros.h" |
| #include "base/memory/memory_pressure_listener.h" |
| #include "base/memory/weak_ptr.h" |
| #include "base/strings/string_split.h" |
| #include "base/time/time.h" |
| #include "net/base/net_export.h" |
| #include "net/disk_cache/disk_cache.h" |
| #include "net/disk_cache/memory/mem_entry_impl.h" |
| |
| namespace net { |
| class NetLog; |
| } // namespace net |
| |
| namespace disk_cache { |
| |
| // This class implements the Backend interface. An object of this class handles |
| // the operations of the cache without writing to disk. |
| class NET_EXPORT_PRIVATE MemBackendImpl final : public Backend { |
| public: |
| explicit MemBackendImpl(net::NetLog* net_log); |
| ~MemBackendImpl() override; |
| |
| // Returns an instance of a Backend implemented only in memory. The returned |
| // object should be deleted when not needed anymore. max_bytes is the maximum |
| // size the cache can grow to. If zero is passed in as max_bytes, the cache |
| // will determine the value to use based on the available memory. The returned |
| // pointer can be NULL if a fatal error is found. |
| static std::unique_ptr<MemBackendImpl> CreateBackend(int64_t max_bytes, |
| net::NetLog* net_log); |
| |
| // Performs general initialization for this current instance of the cache. |
| bool Init(); |
| |
| // Sets the maximum size for the total amount of data stored by this instance. |
| bool SetMaxSize(int64_t max_bytes); |
| |
| // Returns the maximum size for a file to reside on the cache. |
| int64_t MaxFileSize() const override; |
| |
| // These next methods (before the implementation of the Backend interface) are |
| // called by MemEntryImpl to update the state of the backend during the entry |
| // lifecycle. |
| |
| // Signals that new entry has been created, and should be placed in |
| // |lru_list_| so that it is eligable for eviction. |
| void OnEntryInserted(MemEntryImpl* entry); |
| |
| // Signals that an entry has been updated, and thus should be moved to the end |
| // of |lru_list_|. |
| void OnEntryUpdated(MemEntryImpl* entry); |
| |
| // Signals that an entry has been doomed, and so it should be removed from the |
| // list of active entries as appropriate, as well as removed from the |
| // |lru_list_|. |
| void OnEntryDoomed(MemEntryImpl* entry); |
| |
| // Adjust the current size of this backend by |delta|. This is used to |
| // determine if eviction is necessary and when eviction is finished. |
| void ModifyStorageSize(int32_t delta); |
| |
| // Returns true if the cache's size is greater than the maximum allowed |
| // size. |
| bool HasExceededStorageSize() const; |
| |
| // Sets a callback to be posted after we are destroyed. Should be called at |
| // most once. |
| void SetPostCleanupCallback(base::OnceClosure cb); |
| |
| // Backend interface. |
| int32_t GetEntryCount() const override; |
| EntryResult OpenOrCreateEntry(const std::string& key, |
| net::RequestPriority request_priority, |
| EntryResultCallback callback) override; |
| EntryResult OpenEntry(const std::string& key, |
| net::RequestPriority request_priority, |
| EntryResultCallback callback) override; |
| EntryResult CreateEntry(const std::string& key, |
| net::RequestPriority request_priority, |
| EntryResultCallback callback) override; |
| net::Error DoomEntry(const std::string& key, |
| net::RequestPriority priority, |
| CompletionOnceCallback callback) override; |
| net::Error DoomAllEntries(CompletionOnceCallback callback) override; |
| net::Error DoomEntriesBetween(base::Time initial_time, |
| base::Time end_time, |
| CompletionOnceCallback callback) override; |
| net::Error DoomEntriesSince(base::Time initial_time, |
| CompletionOnceCallback callback) override; |
| int64_t CalculateSizeOfAllEntries( |
| Int64CompletionOnceCallback callback) override; |
| int64_t CalculateSizeOfEntriesBetween( |
| base::Time initial_time, |
| base::Time end_time, |
| Int64CompletionOnceCallback callback) override; |
| std::unique_ptr<Iterator> CreateIterator() override; |
| void GetStats(base::StringPairs* stats) override {} |
| void OnExternalCacheHit(const std::string& key) override; |
| size_t DumpMemoryStats( |
| base::trace_event::ProcessMemoryDump* pmd, |
| const std::string& parent_absolute_name) const override; |
| |
| private: |
| class MemIterator; |
| friend class MemIterator; |
| |
| using EntryMap = std::unordered_map<std::string, MemEntryImpl*>; |
| |
| // Deletes entries from the cache until the current size is below the limit. |
| void EvictIfNeeded(); |
| |
| // Deletes entries until the current size is below |goal|. |
| void EvictTill(int target_size); |
| |
| // Called when we get low on memory. |
| void OnMemoryPressure( |
| base::MemoryPressureListener::MemoryPressureLevel memory_pressure_level); |
| |
| EntryMap entries_; |
| |
| // Stored in increasing order of last use time, from least recently used to |
| // most recently used. |
| base::LinkedList<MemEntryImpl> lru_list_; |
| |
| int32_t max_size_; // Maximum data size for this instance. |
| int32_t current_size_; |
| |
| net::NetLog* net_log_; |
| base::OnceClosure post_cleanup_callback_; |
| |
| base::MemoryPressureListener memory_pressure_listener_; |
| |
| base::WeakPtrFactory<MemBackendImpl> weak_factory_{this}; |
| |
| DISALLOW_COPY_AND_ASSIGN(MemBackendImpl); |
| }; |
| |
| } // namespace disk_cache |
| |
| #endif // NET_DISK_CACHE_MEMORY_MEM_BACKEND_IMPL_H_ |