Disk cache: Reference CL for the implementation of file format version 3.

net/disk_cache/v3/eviction_v3.h

+// 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.
+
+#ifndef NET_DISK_CACHE_V3_EVICTION_V3_H_
+#define NET_DISK_CACHE_V3_EVICTION_V3_H_
+
+#include "base/basictypes.h"
+#include "base/memory/weak_ptr.h"
+#include "net/base/completion_callback.h"
+#include "net/disk_cache/v3/disk_format_v3.h"
+#include "net/disk_cache/v3/index_table.h"
+
+namespace disk_cache {
+
+class BackendImplV3;
+class EntryImplV3;
+
+// This class implements the eviction algorithm for the cache and it is tightly
+// integrated with BackendImpl.
+class EvictionV3 {
+ public:
+  EvictionV3();
+  ~EvictionV3();
+
+  void Init(BackendImplV3* backend);
+  void Stop();
+
+  // Deletes entries from the cache until the current size is below the limit.
+  // If empty is true, the whole cache will be trimmed, regardless of being in
+  // use.
+  void TrimCache();
+  int TrimAllCache(const net::CompletionCallback& callback);
+
+  // Notifications of interesting events for a given entry.
+  void OnOpenEntry(EntryImplV3* entry);
+  void OnCreateEntry(EntryImplV3* entry);
+  void OnResurrectEntry(EntryImplV3* entry);
+  void OnEvictEntryComplete();
+
+  // Testing interface.
+  void SetTestMode();
+  void TrimDeletedList(bool empty);
+
+ private:
+  void PostDelayedTrim();
+  void DelayedTrim();
+  bool ShouldTrim();
+  bool ShouldTrimDeleted();
+  int EvictEntry(uint32 hash, Addr address);
+
+  // Returns false when done trimming the cache.
+  bool TrimCacheImpl();
+  void TrimDeleted(bool empty);
+
+  bool EvictionV3::CellIsOldEnough(const IndexIterator& iterator,
+                                   int multiplier);
+  EntryGroup SelectListByLength();
+  void ReportListStats(int time1, int time2, int time3);
+
+  BackendImplV3* backend_;
+  IndexTable* index_;
+  IndexHeaderV3* header_;
+  int max_size_;
+  int trim_delays_;
+  int index_size_;
+  bool lru_;
+  bool first_trim_;
+  bool trimming_;
+  bool delay_trim_;
+  bool init_;
+  bool test_mode_;
+  bool empty_;
+  base::WeakPtrFactory<EvictionV3> ptr_factory_;
+  IndexIterator no_use_cells_;
+  IndexIterator low_use_cells_;
+  IndexIterator high_use_cells_;
+  IndexIterator* cells_to_evict_;
+  net::CompletionCallback callback_;
+
+  DISALLOW_COPY_AND_ASSIGN(EvictionV3);
+};
+
+}  // namespace disk_cache
+
+#endif  // NET_DISK_CACHE_V3_EVICTION_V3_H_