Make synchronous methods on disk_cache::SimpleEntryImpl() reentrant.

net/disk_cache/simple/simple_entry_impl.h

 // Copyright (c) 2013 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.
 
 #ifndef NET_DISK_CACHE_SIMPLE_SIMPLE_ENTRY_IMPL_H_
 #define NET_DISK_CACHE_SIMPLE_SIMPLE_ENTRY_IMPL_H_
 
 #include <string>
 
+#include "base/file_path.h"
 #include "base/memory/weak_ptr.h"
 #include "base/threading/thread_checker.h"
 #include "net/disk_cache/disk_cache.h"
+#include "net/disk_cache/simple/simple_disk_format.h"
 
 namespace net {
 class IOBuffer;
 }
 
 namespace disk_cache {
 
 class SimpleSynchronousEntry;
 
 // SimpleEntryImpl is the IO thread interface to an entry in the very simple
@@ skipping 65 matching lines @@
       int result);
 
   // Called after a SimpleSynchronousEntry has completed an asynchronous IO
   // operation, such as ReadData() or WriteData(). Calls |completion_callback|.
   static void EntryOperationComplete(
       const CompletionCallback& completion_callback,
       base::WeakPtr<SimpleEntryImpl> entry,
       SimpleSynchronousEntry* sync_entry,
       int result);
 
+  // Called on construction and also after the completion of asynchronous IO to
+  // initialize the IO thread copies of data returned by synchronous accessor
+  // functions. Copies data from |synchronous_entry_| into |this|, so that
+  // values can be returned during our next IO operation.
+  void SetSynchronousData();

[rvargas (doing something else), 2013/02/13 03:10:36]

I would suggest a different name because it's starting to get confusing what
Synchronous means (as in synchronous_entry_ refers to stuff that happens on a
background thread while here  it means stuff that happens on the IO thread).

SetLocalData()?
UpdateLocalData()?

+
   base::ThreadChecker thread_checker_;
   base::WeakPtrFactory<SimpleEntryImpl> weak_ptr_factory_;
-  std::string key_;
+
+  // |path_| and |key_| are copied from the synchronous entry on construction,
+  // and never updated as they are const.
+  const base::FilePath path_;
+  const std::string key_;
+
+  // |last_used_|, |last_modified_| and |data_size_| are copied from the
+  // synchronous entry at the completion of each item of asynchronous IO.
+  base::Time last_used_;
+  base::Time last_modified_;
+  int32 data_size_[kSimpleEntryFileCount];
 
   // The |synchronous_entry_| is the worker thread object that performs IO on
   // entries.
   SimpleSynchronousEntry* synchronous_entry_;
 
   // Set to true when a worker operation is posted on the |synchronous_entry_|,
   // and false after. Used to insure thread safety by not allowing multiple
   // threads to access the |synchronous_entry_| simultaniously.
   bool synchronous_entry_in_use_by_worker_;
 
   bool has_been_doomed_;
 };
 
 }  // namespace disk_cache
 
 #endif  // NET_DISK_CACHE_SIMPLE_SIMPLE_ENTRY_IMPL_H_