Disk cache: Add a hash to the entry's internal data.

net/disk_cache/backend_impl.cc

Index: net/disk_cache/backend_impl.cc
===================================================================
--- net/disk_cache/backend_impl.cc	(revision 110637)
+++ net/disk_cache/backend_impl.cc	(working copy)
@@ -819,8 +819,8 @@
   open_entries_[entry_address.value()] = cache_entry;
 
   // Save the entry.
-  block_files_.GetFile(entry_address)->Store(cache_entry->entry());
-  block_files_.GetFile(node_address)->Store(cache_entry->rankings());
+  cache_entry->entry()->Store();
+  cache_entry->rankings()->Store();

[gavinp, 2011/11/29 15:47:42]

Nice.

   IncreaseNumEntries();
   entry_count_++;
 
@@ -1643,9 +1643,6 @@
   if (!cache_entry->LoadNodeAddress())
     return ERR_READ_FAILURE;
 
-  // Prevent overwriting the dirty flag on the destructor.
-  cache_entry->SetDirtyFlag(GetCurrentEntryId());
-
   if (!rankings_.SanityCheck(cache_entry->rankings(), false)) {
     STRESS_NOTREACHED();
     cache_entry->SetDirtyFlag(0);
@@ -1665,6 +1662,9 @@
     cache_entry->FixForDelete();
   }
 
+  // Prevent overwriting the dirty flag on the destructor.
+  cache_entry->SetDirtyFlag(GetCurrentEntryId());

[gavinp, 2011/11/29 15:47:42]

Why is this moving beyond the two sanity-check blocks?

[rvargas (doing something else), 2011/11/29 19:08:56]

Because this is reading Rankings; we want the first access to read the hash and
verify it. On the other hand, all code paths end up calling SetDirtyFlag (even
if a future refactor decides to return after one of the sanity checks)

+
   if (cache_entry->dirty()) {
     Trace("Dirty entry 0x%p 0x%x", reinterpret_cast<void*>(cache_entry.get()),
           address.value());
@@ -2219,8 +2219,7 @@
     }
   }
 
-  RankingsNode* rankings = cache_entry->rankings()->Data();
-  return ok && !rankings->dummy;
+  return ok && cache_entry->rankings()->VerifyHash();
 }
 
 int BackendImpl::MaxBuffersSize() {