Avoid fragmenting the heap too much while reconstructing the index.

net/disk_cache/simple/simple_util.h

 // Copyright (c) 2013 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.
 
 #ifndef NET_DISK_CACHE_SIMPLE_SIMPLE_UTIL_H_
 #define NET_DISK_CACHE_SIMPLE_SIMPLE_UTIL_H_
 
 #include <string>
 
 #include "base/basictypes.h"
+#include "base/strings/string_piece.h"
 #include "net/base/net_export.h"
 
 namespace base {
 class FilePath;
 class Time;
 }
 
 namespace disk_cache {
 
 namespace simple_util {
 
 NET_EXPORT_PRIVATE std::string ConvertEntryHashKeyToHexString(uint64 hash_key);
 
 // |key| is the regular cache key, such as an URL.
 // Returns the Hex ascii representation of the uint64 hash_key.
 NET_EXPORT_PRIVATE std::string GetEntryHashKeyAsHexString(
     const std::string& key);
 
 // |key| is the regular HTTP Cache key, which is a URL.
 // Returns the hash of the key as uint64.
 NET_EXPORT_PRIVATE uint64 GetEntryHashKey(const std::string& key);
 
 // Parses the |hash_key| string into a uint64 buffer.
 // |hash_key| string must be of the form: FFFFFFFFFFFFFFFF .
 NET_EXPORT_PRIVATE bool GetEntryHashKeyFromHexString(
-    const std::string& hash_key,
+    const base::StringPiece& hash_key,
     uint64* hash_key_out);
 
 // Given a |key| for a (potential) entry in the simple backend and the |index|
 // of a stream on that entry, returns the filename in which that stream would be
 // stored.
 NET_EXPORT_PRIVATE std::string GetFilenameFromKeyAndIndex(
     const std::string& key,
     int index);
 
 // Same as |GetFilenameFromKeyAndIndex| above, but using a hex string.
@@ skipping 17 matching lines @@
 
 // Fills |out_time| with the time the file last modified time.
 // TODO(gavinp): Remove this function.
 NET_EXPORT_PRIVATE bool GetMTime(const base::FilePath& path,
                                  base::Time* out_mtime);
 }  // namespace simple_backend
 
 }  // namespace disk_cache
 
 #endif  // NET_DISK_CACHE_SIMPLE_SIMPLE_UTIL_H_