Count exact cache size for time ranges

components/browsing_data/content/conditional_cache_counting_helper.cc

 // Copyright 2016 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 "components/browsing_data/content/conditional_cache_counting_helper.h"
 
 #include "base/callback.h"
 #include "base/single_thread_task_runner.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "content/public/browser/browser_thread.h"
@@ skipping 18 matching lines @@
 }
 
 ConditionalCacheCountingHelper::ConditionalCacheCountingHelper(
     base::Time begin_time,
     base::Time end_time,
     net::URLRequestContextGetter* main_context_getter,
     net::URLRequestContextGetter* media_context_getter)
     : calculation_result_(0),
       begin_time_(begin_time),
       end_time_(end_time),
+      is_cancelled_(false),
       is_finished_(false),
       main_context_getter_(main_context_getter),
       media_context_getter_(media_context_getter),
       next_cache_state_(CacheState::NONE),
       cache_(nullptr),
       iterator_(nullptr),
+      current_entry_(nullptr),
       weak_ptr_factory_(this) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 }
 
 ConditionalCacheCountingHelper::~ConditionalCacheCountingHelper() {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 }
 
 base::WeakPtr<ConditionalCacheCountingHelper>
 ConditionalCacheCountingHelper::CountAndDestroySelfWhenFinished(
     const CacheCountCallback& result_callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   DCHECK(!result_callback.is_null());
   result_callback_ = result_callback;
   calculation_result_ = 0;
 
   BrowserThread::PostTask(
       BrowserThread::IO, FROM_HERE,
       base::Bind(&ConditionalCacheCountingHelper::CountHttpCacheOnIOThread,
                  base::Unretained(this)));
   return weak_ptr_factory_.GetWeakPtr();
 }
 
+void ConditionalCacheCountingHelper::CancelCounting() {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  DCHECK(!is_finished_);
+  is_cancelled_ = true;
+}
+
 bool ConditionalCacheCountingHelper::IsFinished() {
   return is_finished_;
 }
 
 void ConditionalCacheCountingHelper::Finished() {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   DCHECK(!is_finished_);
   is_finished_ = true;
   result_callback_.Run(calculation_result_);
   base::ThreadTaskRunnerHandle::Get()->DeleteSoon(FROM_HERE, this);
@@ skipping 56 matching lines @@
                                 ? CacheState::CREATE_MEDIA
                                 : CacheState::DONE;
 
         // |cache_| can be null if it cannot be initialized.
         if (cache_) {
           if (begin_time_.is_null() && end_time_.is_max()) {
             rv = cache_->CalculateSizeOfAllEntries(
                 base::Bind(&ConditionalCacheCountingHelper::DoCountCache,
                            base::Unretained(this)));
           } else {
-            // TODO(dullweber): Readd code for counting with timeout.
             // TODO(dullweber): Implement faster counting for SimpleBackendImpl.
-            rv = cache_->CalculateSizeOfAllEntries(
-                base::Bind(&ConditionalCacheCountingHelper::DoCountCache,
-                           base::Unretained(this)));
+            rv = CountEntries(cache_);
           }
           cache_ = NULL;
         }
         break;
       }
       case CacheState::DONE: {
         cache_ = NULL;
         next_cache_state_ = CacheState::NONE;
         // Notify the UI thread that we are done.
         BrowserThread::PostTask(
             BrowserThread::UI, FROM_HERE,
             base::Bind(&ConditionalCacheCountingHelper::Finished,
                        base::Unretained(this)));
         return;
       }
       case CacheState::NONE: {
         NOTREACHED() << "bad state";
         return;
       }
     }
   }
 }
 
+int ConditionalCacheCountingHelper::CountEntries(disk_cache::Backend* backend) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
+  iterator_ = backend->CreateIterator();
+  current_entry_ = nullptr;
+  IterateOverEntries(net::OK);
+  return net::ERR_IO_PENDING;
+}
+
+void ConditionalCacheCountingHelper::IterateOverEntries(int error) {
+  while (error != net::ERR_IO_PENDING) {
+    if (is_cancelled_) {
+      if (current_entry_)
+        current_entry_->Close();
+      iterator_.reset();
+      DoCountCache(net::ERR_ABORTED);
+      return;
+    }
+    if (error == net::ERR_FAILED) {
+      // The iteration finished successfully or we can no longer iterate
+      // (e.g. the cache was destroyed). We cannot distinguish between the two,
+      // but we know that there is nothing more that we can do, so we return to
+      // the main calculation loop.
+      iterator_.reset();
+      DoCountCache(net::OK);
+      return;
+    }
+
+    if (current_entry_) {
+      if (current_entry_->GetLastUsed() >= begin_time_ &&
+          current_entry_->GetLastUsed() < end_time_) {
+        calculation_result_ += current_entry_->GetEntrySize();
+      }
+      current_entry_->Close();
+    }
+
+    error = iterator_->OpenNextEntry(
+        &current_entry_,
+        base::Bind(&ConditionalCacheCountingHelper::IterateOverEntries,
+                   base::Unretained(this)));
+  }
+}
+
 }  // namespace browsing_data