Disk cache: Re-initialize stats counters if they are zero on-disk.

net/disk_cache/blockfile/stats.cc

 // Copyright (c) 2011 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/stats.h"
 
 #include "base/format_macros.h"
 #include "base/logging.h"
 #include "base/metrics/bucket_ranges.h"
 #include "base/metrics/histogram.h"
@@ skipping 89 matching lines @@
 
 bool Stats::Init(void* data, int num_bytes, Addr address) {
   OnDiskStats local_stats;
   OnDiskStats* stats = &local_stats;
   if (!num_bytes) {
     memset(stats, 0, sizeof(local_stats));
     local_stats.signature = kDiskSignature;
     local_stats.size = sizeof(local_stats);
   } else if (num_bytes >= static_cast<int>(sizeof(*stats))) {
     stats = reinterpret_cast<OnDiskStats*>(data);
-    if (!VerifyStats(stats))
-      return false;
+    if (!VerifyStats(stats)) {
+      memset(&local_stats, 0, sizeof(local_stats));
+      if (memcmp(stats, &local_stats, sizeof(local_stats))) {
+        return false;
+      } else {
+        // The storage is empty which means that SerializeStats() was never
+        // called on the last run. Just re-initialize everything.
+        local_stats.signature = kDiskSignature;
+        local_stats.size = sizeof(local_stats);
+        stats = &local_stats;
+      }
+    }
   } else {
     return false;
   }
 
   storage_addr_ = address;
 
   memcpy(data_sizes_, stats->data_sizes, sizeof(data_sizes_));
   memcpy(counters_, stats->counters, sizeof(counters_));
 
   // Clean up old value.
@@ skipping 188 matching lines @@
 int Stats::GetRatio(Counters hit, Counters miss) const {
   int64 ratio = GetCounter(hit) * 100;
   if (!ratio)
     return 0;
 
   ratio /= (GetCounter(hit) + GetCounter(miss));
   return static_cast<int>(ratio);
 }
 
 }  // namespace disk_cache