Disk cache: Add support for having a sparse entry block that...

net/disk_cache/rankings.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.
 
 #ifndef NET_DISK_CACHE_RANKINGS_H_
 #define NET_DISK_CACHE_RANKINGS_H_
 
 #include <list>
@@ skipping 77 matching lines @@
     Rankings* rankings_;
     DISALLOW_EVIL_CONSTRUCTORS(ScopedRankingsBlock);
   };
 
   // If we have multiple lists, we have to iterate through all at the same time.
   // This structure keeps track of where we are on the iteration.
   struct Iterator {
     List list;                     // Which entry was returned to the user.
     CacheRankingsBlock* nodes[3];  // Nodes on the first three lists.
     Rankings* my_rankings;
-    Iterator(Rankings* rankings) {
+    explicit Iterator(Rankings* rankings) {
       memset(this, 0, sizeof(Iterator));
       my_rankings = rankings;
     }
     ~Iterator() {
       for (int i = 0; i < 3; i++)
         ScopedRankingsBlock(my_rankings, nodes[i]);
     }
   };
 
   Rankings() : init_(false) {}
@@ skipping 61 matching lines @@
   // Returns true if addr is the head or tail of any list.
   bool IsHead(CacheAddr addr);
   bool IsTail(CacheAddr addr);
 
   // Controls tracking of nodes used for enumerations.
   void TrackRankingsBlock(CacheRankingsBlock* node, bool start_tracking);
 
   // Updates the iterators whenever node is being changed.
   void UpdateIterators(CacheRankingsBlock* node);
 
+  // Verifies that no iterator gets invalidated by changing a node.
+  void NotAnIterator(CacheRankingsBlock* node);
+
   // Keeps track of the number of entries on a list.
   void IncrementCounter(List list);
   void DecrementCounter(List list);
 
   bool init_;
   bool count_lists_;
   Addr heads_[LAST_ELEMENT];
   Addr tails_[LAST_ELEMENT];
   BackendImpl* backend_;
   LruData* control_data_;  // Data related to the LRU lists.
   IteratorList iterators_;
 
   DISALLOW_COPY_AND_ASSIGN(Rankings);
 };
 
 }  // namespace disk_cache
 
 #endif  // NET_DISK_CACHE_RANKINGS_H_