diff -r 000000000000 -r 6474c204b198 netwerk/cache/nsDiskCacheBlockFile.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/netwerk/cache/nsDiskCacheBlockFile.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,69 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* vim: set sw=4 ts=8 et tw=80 : */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef _nsDiskCacheBlockFile_h_
+#define _nsDiskCacheBlockFile_h_
+
+#include "mozilla/MemoryReporting.h"
+#include "nsIFile.h"
+#include "nsDiskCache.h"
+
+/******************************************************************************
+ *  nsDiskCacheBlockFile
+ *
+ *  The structure of a cache block file is a 4096 bytes bit map, followed by
+ *  some number of blocks of mBlockSize.  The creator of a
+ *  nsDiskCacheBlockFile object must provide the block size for a given file.
+ *
+ *****************************************************************************/
+class nsDiskCacheBlockFile {
+public:
+    nsDiskCacheBlockFile()
+           : mFD(nullptr)
+           , mBitMap(nullptr)
+           , mBlockSize(0)
+           , mBitMapWords(0)
+           , mFileSize(0)
+           , mBitMapDirty(false)
+            {}
+    ~nsDiskCacheBlockFile() { (void) Close(true); }
+    
+    nsresult  Open( nsIFile *  blockFile, uint32_t  blockSize,
+                    uint32_t  bitMapSize, nsDiskCache::CorruptCacheInfo *  corruptInfo);
+    nsresult  Close(bool flush);
+
+    /*
+     * Trim
+     * Truncates the block file to the end of the last allocated block.
+     */
+    nsresult  Trim() { return nsDiskCache::Truncate(mFD, CalcBlockFileSize()); }
+    nsresult  DeallocateBlocks( int32_t  startBlock, int32_t  numBlocks);
+    nsresult  WriteBlocks( void * buffer, uint32_t size, int32_t  numBlocks, 
+                           int32_t * startBlock);
+    nsresult  ReadBlocks( void * buffer, int32_t  startBlock, int32_t  numBlocks, 
+                          int32_t * bytesRead);
+
+    size_t   SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf);
+
+private:
+    nsresult  FlushBitMap();
+    int32_t   AllocateBlocks( int32_t  numBlocks);
+    nsresult  VerifyAllocation( int32_t startBlock, int32_t numBLocks);
+    uint32_t  CalcBlockFileSize();
+    bool   Write(int32_t offset, const void *buf, int32_t amount);
+
+/**
+ *  Data members
+ */
+    PRFileDesc *                mFD;
+    uint32_t *                  mBitMap;      // XXX future: array of bit map blocks
+    uint32_t                    mBlockSize;
+    uint32_t                    mBitMapWords;
+    int32_t                     mFileSize;
+    bool                        mBitMapDirty;
+};
+
+#endif // _nsDiskCacheBlockFile_h_