Add net to the repository.

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@14 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 178 insertions, 0 deletions

diff --git a/net/disk_cache/rankings.h b/net/disk_cache/rankings.h
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+// Copyright 2008, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//    * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//    * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//    * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// 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>
+
+#include "net/disk_cache/addr.h"
+#include "net/disk_cache/mapped_file.h"
+#include "net/disk_cache/storage_block.h"
+
+namespace disk_cache {
+
+class BackendImpl;
+
+// Type of crashes generated for the unit tests.
+enum RankCrashes {
+  NO_CRASH = 0,
+  INSERT_EMPTY_1,
+  INSERT_EMPTY_2,
+  INSERT_EMPTY_3,
+  INSERT_ONE_1,
+  INSERT_ONE_2,
+  INSERT_ONE_3,
+  INSERT_LOAD_1,
+  INSERT_LOAD_2,
+  REMOVE_ONE_1,
+  REMOVE_ONE_2,
+  REMOVE_ONE_3,
+  REMOVE_ONE_4,
+  REMOVE_HEAD_1,
+  REMOVE_HEAD_2,
+  REMOVE_HEAD_3,
+  REMOVE_HEAD_4,
+  REMOVE_TAIL_1,
+  REMOVE_TAIL_2,
+  REMOVE_TAIL_3,
+  REMOVE_LOAD_1,
+  REMOVE_LOAD_2,
+  REMOVE_LOAD_3,
+  MAX_CRASH
+};
+
+// This class handles the ranking information for the cache.
+class Rankings {
+ public:
+  // This class provides a specialized version of scoped_ptr, that calls
+  // Rankings whenever a CacheRankingsBlock is deleted, to keep track of cache
+  // iterators that may go stale.
+  class ScopedRankingsBlock : public scoped_ptr<CacheRankingsBlock> {
+   public:
+    explicit ScopedRankingsBlock(Rankings* rankings) : rankings_(rankings) {}
+    ScopedRankingsBlock(Rankings* rankings, CacheRankingsBlock* node)
+        : rankings_(rankings), scoped_ptr<CacheRankingsBlock>(node) {}
+
+    ~ScopedRankingsBlock() {
+      rankings_->FreeRankingsBlock(get());
+    }
+
+    // scoped_ptr::reset will delete the object.
+    void reset(CacheRankingsBlock* p = NULL) {
+      if (p != get())
+        rankings_->FreeRankingsBlock(get());
+      scoped_ptr::reset(p);
+    }
+
+   private:
+    Rankings* rankings_;
+    DISALLOW_EVIL_CONSTRUCTORS(ScopedRankingsBlock);
+  };
+
+  Rankings()
+      : init_(false), head_(0), tail_(0) {}
+  ~Rankings() {}
+
+  bool Init(BackendImpl* backend);
+
+  // Restores original state, leaving the object ready for initialization.
+  void Reset();
+
+  // Inserts a given entry at the head of the queue.
+  void Insert(CacheRankingsBlock* node, bool modified);
+
+  // Removes a given entry from the LRU list.
+  void Remove(CacheRankingsBlock* node);
+
+  // Moves a given entry to the head.
+  void UpdateRank(CacheRankingsBlock* node, bool modified);
+
+  // Iterates through the list.
+  CacheRankingsBlock* GetNext(CacheRankingsBlock* node);
+  CacheRankingsBlock* GetPrev(CacheRankingsBlock* node);
+  void FreeRankingsBlock(CacheRankingsBlock* node);
+
+  // Peforms a simple self-check of the list, and returns the number of items
+  // or an error code (negative value).
+  int SelfCheck();
+
+  // Returns false if the entry is clearly invalid. from_list is true if the
+  // node comes from the LRU list.
+  bool SanityCheck(CacheRankingsBlock* node, bool from_list);
+
+ private:
+  typedef std::pair<CacheAddr, CacheRankingsBlock*> IteratorPair;
+  typedef std::list<IteratorPair> IteratorList;
+
+  Addr ReadHead();
+  Addr ReadTail();
+  void WriteHead();
+  void WriteTail();
+
+  // Gets the rankings information for a given rankings node.
+  bool GetRanking(CacheRankingsBlock* rankings);
+
+  // Finishes a list modification after a crash.
+  void CompleteTransaction();
+  void FinishInsert(CacheRankingsBlock* rankings);
+  void RevertRemove(CacheRankingsBlock* rankings);
+
+  // Returns false if this entry will not be recognized as dirty (called during
+  // selfcheck).
+  bool CheckEntry(CacheRankingsBlock* rankings);
+
+  // Returns false if node is not properly linked.
+  bool CheckLinks(CacheRankingsBlock* node, CacheRankingsBlock* prev,
+                  CacheRankingsBlock* next);
+
+  // Checks the links between two consecutive nodes.
+  bool CheckSingleLink(CacheRankingsBlock* prev, CacheRankingsBlock* next);
+
+  // 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);
+
+  bool init_;
+  Addr head_;
+  Addr tail_;
+  BlockFileHeader* header_;  // Header of the block-file used to store rankings.
+  BackendImpl* backend_;
+  IteratorList iterators_;
+
+  DISALLOW_EVIL_CONSTRUCTORS(Rankings);
+};
+
+}  // namespace disk_cache
+
+#endif  // NET_DISK_CACHE_RANKINGS_H__