Calculate the size of all cache entries between two points in time.

net/disk_cache/disk_cache.h

 // Copyright (c) 2012 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://dev.chromium.org/developers/design-documents/network-stack/disk-cache
 
 #ifndef NET_DISK_CACHE_DISK_CACHE_H_
 #define NET_DISK_CACHE_DISK_CACHE_H_
 
 #include <stdint.h>
 
 #include <memory>
 #include <string>
 #include <vector>
 
 #include "base/memory/ref_counted.h"
 #include "base/strings/string_split.h"
 #include "base/time/time.h"
 #include "net/base/cache_type.h"
 #include "net/base/completion_callback.h"
+#include "net/base/net_errors.h"
 #include "net/base/net_export.h"
 
 namespace base {
 class FilePath;
 class SingleThreadTaskRunner;
 }
 
 namespace net {
 class IOBuffer;
 class NetLog;
@@ skipping 110 matching lines @@
   // Marks all entries accessed since |initial_time| for deletion. The return
   // value is a net error code. If this method returns ERR_IO_PENDING, the
   // |callback| will be invoked when the operation completes.
   // Entries with |initial_time| <= access time are deleted.
   virtual int DoomEntriesSince(base::Time initial_time,
                                const CompletionCallback& callback) = 0;
 
   // Calculate the total size of the cache. The return value is the size in
   // bytes or a net error code. If this method returns ERR_IO_PENDING,
   // the |callback| will be invoked when the operation completes.
-  virtual int CalculateSizeOfAllEntries(
-      const CompletionCallback& callback) = 0;
+  virtual int CalculateSizeOfAllEntries(const CompletionCallback& callback) = 0;
+
+  // Calculate the size of all cache entries accessed between |initial_time| and
+  // |end_time|.
+  // The return value is the size in bytes or a net error code. The default
+  // implementation returns ERR_NOT_IMPLEMENTED and should only be overwritten
+  // if there is an efficient way for the backend to determine the size for a
+  // subset of the cache without reading the whole cache from disk.
+  // If this method returns ERR_IO_PENDING, the |callback| will be invoked when
+  // the operation completes.
+  virtual int CalculateSizeOfEntriesBetween(base::Time initial_time,
+                                            base::Time end_time,
+                                            const CompletionCallback& callback);
 
   // Returns an iterator which will enumerate all entries of the cache in an
   // undefined order.
   virtual std::unique_ptr<Iterator> CreateIterator() = 0;
 
   // Return a list of cache statistics.
   virtual void GetStats(base::StringPairs* stats) = 0;
 
   // Called whenever an external cache in the system reuses the resource
   // referred to by |key|.
@@ skipping 167 matching lines @@
     entry->Close();
   }
 };
 
 // Automatically closes an entry when it goes out of scope.
 typedef std::unique_ptr<Entry, EntryDeleter> ScopedEntryPtr;
 
 }  // namespace disk_cache
 
 #endif  // NET_DISK_CACHE_DISK_CACHE_H_