Disk cache: Keep a map of all open entries....

net/disk_cache/backend_impl.h

 // Copyright (c) 2006-2008 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_BACKEND_IMPL_H_
 #define NET_DISK_CACHE_BACKEND_IMPL_H_
 
+#include "base/hash_tables.h"
 #include "base/timer.h"
 #include "net/disk_cache/block_files.h"
 #include "net/disk_cache/disk_cache.h"
 #include "net/disk_cache/eviction.h"
 #include "net/disk_cache/rankings.h"
 #include "net/disk_cache/stats.h"
 #include "net/disk_cache/trace.h"
 
 namespace disk_cache {
 
@@ skipping 72 matching lines @@
   // method checks it and takes the appropriate action.
   void RecoveredEntry(CacheRankingsBlock* rankings);
 
   // Permanently deletes an entry, but still keeps track of it.
   void InternalDoomEntry(EntryImpl* entry);
 
   // Removes all references to this entry.
   void RemoveEntry(EntryImpl* entry);
 
   // This method must be called whenever an entry is released for the last time.
-  void CacheEntryDestroyed();
+  // |address| is the cache address of the entry.
+  void CacheEntryDestroyed(Addr address);
+
+  // Returns true if the data stored by the provided |rankings| points to an
+  // open entry, false otherwise.
+  bool IsOpen(CacheRankingsBlock* rankings) const;
 
   // Returns the id being used on this run of the cache.
-  int32 GetCurrentEntryId();
+  int32 GetCurrentEntryId() const;
 
   // Returns the maximum size for a file to reside on the cache.
   int MaxFileSize() const;
 
   // A user data block is being created, extended or truncated.
   void ModifyStorageSize(int32 old_size, int32 new_size);
 
   // Logs requests that are denied due to being too big.
   void TooMuchStorageRequested(int32 size);
 
@@ skipping 46 matching lines @@
   void ClearRefCountForTest();
 
   // Peforms a simple self-check, and returns the number of dirty items
   // or an error code (negative value).
   int SelfCheck();
 
   // Same bahavior as OpenNextEntry but walks the list from back to front.
   bool OpenPrevEntry(void** iter, Entry** prev_entry);
 
  private:
+  typedef base::hash_map<CacheAddr, EntryImpl*> EntriesMap;
+
   // Creates a new backing file for the cache index.
   bool CreateBackingStore(disk_cache::File* file);
   bool InitBackingStore(bool* file_created);
   void AdjustMaxCacheSize(int table_len);
 
   // Deletes the cache and starts again.
   void RestartCache();
   void PrepareForRestart();
 
   // Creates a new entry object and checks to see if it is dirty. Returns zero
@@ skipping 52 matching lines @@
   bool CheckEntry(EntryImpl* cache_entry);
 
   scoped_refptr<MappedFile> index_;  // The main cache index.
   std::wstring path_;  // Path to the folder used as backing storage.
   Index* data_;  // Pointer to the index data.
   BlockFiles block_files_;  // Set of files used to store all data.
   Rankings rankings_;  // Rankings to be able to trim the cache.
   uint32 mask_;  // Binary mask to map a hash to the hash table.
   int32 max_size_;  // Maximum data size for this instance.
   Eviction eviction_;  // Handler of the eviction algorithm.
+  EntriesMap open_entries_;  // Map of open entries.
   int num_refs_;  // Number of referenced cache entries.
   int max_refs_;  // Max number of referenced cache entries.
   int num_pending_io_;  // Number of pending IO operations.
   net::CacheType cache_type_;
   int uma_report_;  // Controls transmision of UMA data.
   uint32 user_flags_;  // Flags set by the user.
   bool init_;  // controls the initialization of the system.
   bool restarted_;
   bool unit_test_;
   bool read_only_;  // Prevents updates of the rankings data (used by tools).
   bool disabled_;
   bool new_eviction_;  // What eviction algorithm should be used.
   bool first_timer_;  // True if the timer has not been called.
 
   Stats stats_;  // Usage statistcs.
   base::RepeatingTimer<BackendImpl> timer_;  // Usage timer.
   scoped_refptr<TraceObject> trace_object_;  // Inits internal tracing.
 
   DISALLOW_EVIL_CONSTRUCTORS(BackendImpl);
 };
 
 // Returns the prefered max cache size given the available disk space.
 int PreferedCacheSize(int64 available);
 
 }  // namespace disk_cache
 
 #endif  // NET_DISK_CACHE_BACKEND_IMPL_H_