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

net/disk_cache/blockfile/backend_impl.cc

 // 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.
 
 #include "net/disk_cache/blockfile/backend_impl.h"
 
 #include <limits>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 1252 matching lines @@
   background_queue_.DoomEntriesSince(initial_time, callback);
   return net::ERR_IO_PENDING;
 }
 
 int BackendImpl::CalculateSizeOfAllEntries(const CompletionCallback& callback) {
   DCHECK(!callback.is_null());
   background_queue_.CalculateSizeOfAllEntries(callback);
   return net::ERR_IO_PENDING;
 }
 
+int BackendImpl::CalculateSizeOfEntriesBetween(
+    base::Time initial_time,
+    base::Time end_time,
+    const CompletionCallback& callback) {
+  // Calculating the size of a subset of cache entries is not implemented
+  // because it would require to open and read all entries from disk.
+  return net::ERR_NOT_IMPLEMENTED;

[gavinp, 2017/01/12 16:07:35]

Why not move all of these ERR_NOT_IMPLEMENTED versions up into the
disk_cache::Backend directly? Seems more logical than repeating this over and
over again.

+}
+
 class BackendImpl::IteratorImpl : public Backend::Iterator {
  public:
   explicit IteratorImpl(base::WeakPtr<InFlightBackendIO> background_queue)
       : background_queue_(background_queue),
         iterator_(new Rankings::Iterator()) {
   }
 
   ~IteratorImpl() override {
     if (background_queue_)
       background_queue_->EndEnumeration(std::move(iterator_));
@@ skipping 826 matching lines @@
     if (total_memory > kMaxBuffersSize || total_memory <= 0)
       total_memory = kMaxBuffersSize;
 
     done = true;
   }
 
   return static_cast<int>(total_memory);
 }
 
 }  // namespace disk_cache