Extend the IOBuffer to the disk cache....

net/disk_cache/disk_cache.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.
 
 // Defines the public interface of the disk cache. For more details see
 // http://wiki/Main/ChromeDiskCacheBackend
 
 #ifndef NET_DISK_CACHE_DISK_CACHE_H__
 #define NET_DISK_CACHE_DISK_CACHE_H__
 
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/time.h"
 #include "net/base/completion_callback.h"
 
+namespace net {
+class IOBuffer;
+}
+
 namespace disk_cache {
 
 class Entry;
 class Backend;
 
 // Returns an instance of the Backend. path points to a folder where
 // the cached data will be stored. This cache instance must be the only object
 // that will be reading or writing files to that folder. The returned object
 // should be deleted when not needed anymore. If force is true, and there is
 // a problem with the cache initialization, the files will be deleted and a
@@ skipping 88 matching lines @@
   virtual base::Time GetLastModified() const = 0;
 
   // Returns the size of the cache data with the given index.
   virtual int32 GetDataSize(int index) const = 0;
 
   // Copies cache data into the given buffer of length |buf_len|.  If
   // completion_callback is null, then this call blocks until the read
   // operation is complete.  Otherwise, completion_callback will be
   // called on the current thread once the read completes.  Returns the
   // number of bytes read or a network error code. If a completion callback is
-  // provided then it will be called if this function returns ERR_IO_PENDING.
+  // provided then it will be called if this function returns ERR_IO_PENDING,
+  // and a reference to |buf| will be retained until the callback is called.
   // Note that the callback will be invoked in any case, even after Close has
   // been called; in other words, the caller may close this entry without
   // having to wait for all the callbacks, and still rely on the cleanup
   // performed from the callback code.
-  virtual int ReadData(int index, int offset, char* buf, int buf_len,
+  virtual int ReadData(int index, int offset, net::IOBuffer* buf, int buf_len,
                        net::CompletionCallback* completion_callback) = 0;
 
   // Copies cache data from the given buffer of length |buf_len|.  If
   // completion_callback is null, then this call blocks until the write
   // operation is complete.  Otherwise, completion_callback will be
   // called on the current thread once the write completes.  Returns the
   // number of bytes written or a network error code. If a completion callback
-  // is provided then it will be called if this function returns ERR_IO_PENDING.
+  // is provided then it will be called if this function returns ERR_IO_PENDING,
+  // and a reference to |buf| will be retained until the callback is called.
   // Note that the callback will be invoked in any case, even after Close has
   // been called; in other words, the caller may close this entry without
   // having to wait for all the callbacks, and still rely on the cleanup
   // performed from the callback code.
   // If truncate is true, this call will truncate the stored data at the end of
   // what we are writing here.
-  virtual int WriteData(int index, int offset, const char* buf, int buf_len,
+  virtual int WriteData(int index, int offset, net::IOBuffer* buf, int buf_len,
                         net::CompletionCallback* completion_callback,
                         bool truncate) = 0;
 
  protected:
   virtual ~Entry() {}
 };
 
 }  // namespace disk_cache
 
 #endif  // NET_DISK_CACHE_DISK_CACHE_H__