1 files changed, 107 insertions, 0 deletions
diff --git a/net/disk_cache/storage_block.h b/net/disk_cache/storage_block.h
new file mode 100644
index 0000000..7c100fd
--- /dev/null
+++ b/net/disk_cache/storage_block.h
@@ -0,0 +1,107 @@
+// 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_STORAGE_BLOCK_H__
+#define NET_DISK_CACHE_STORAGE_BLOCK_H__
+
+#include "net/disk_cache/addr.h"
+#include "net/disk_cache/mapped_file.h"
+
+namespace disk_cache {
+
+class EntryImpl;
+
+// This class encapsulates common behavior of a single "block" of data that is
+// stored on a block-file. It implements the FileBlock interface, so it can be
+// serialized directly to the backing file.
+// This object provides a memory buffer for the related data, and it can be used
+// to actually share that memory with another instance of the class.
+//
+// The following example shows how to share storage with another object:
+//    StorageBlock<TypeA> a(file, address);
+//    StorageBlock<TypeB> b(file, address);
+//    a.Load();
+//    DoSomething(a.Data());
+//    b.SetData(a.Data());
+//    ModifySomething(b.Data());
+//    // Data modified on the previous call will be saved by b's destructor.
+//    b.set_modified();
+template<typename T>
+class StorageBlock : public FileBlock {
+ public:
+  StorageBlock(MappedFile* file, Addr address);
+  virtual ~StorageBlock();
+
+  // FileBlock interface.
+  virtual void* buffer() const;
+  virtual size_t size() const;
+  virtual DWORD offset() const;
+
+  // Allows the overide of dummy values passed on the constructor.
+  bool LazyInit(MappedFile* file, Addr address);
+
+  // Sets the internal storage to share the momory provided by other instance.
+  void SetData(T* other);
+
+  // Sets the object to lazily save the in-memory data on destruction.
+  void set_modified();
+
+  // Gets a pointer to the internal storage (allocates storage if needed).
+  T* Data();
+
+  // Returns true if there is data associated with this object.
+  bool HasData() const;
+
+  const Addr address() const;
+
+  // Loads and store the data.
+  bool Load();
+  bool Store();
+
+ private:
+  void AllocateData();
+
+  T* data_;
+  MappedFile* file_;
+  Addr address_;
+  bool modified_;
+  bool own_data_;  // Is data_ owned by this object or shared with someone else.
+  bool extended_;  // Used to store an entry of more than one block.
+
+  DISALLOW_EVIL_CONSTRUCTORS(StorageBlock);
+};
+
+typedef StorageBlock<EntryStore> CacheEntryBlock;
+typedef StorageBlock<RankingsNode> CacheRankingsBlock;
+
+}  // namespace disk_cache
+
+#endif  // NET_DISK_CACHE_STORAGE_BLOCK_H__