Fix race condition for non-open/create operations happening after a doom.

net/disk_cache/backend_unittest.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 "base/basictypes.h"
 #include "base/file_util.h"
 #include "base/metrics/field_trial.h"
 #include "base/port.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
@@ skipping 2664 matching lines @@
   ASSERT_EQ(net::OK, CreateEntry("fourth", &entry2));
 
   ASSERT_EQ(4, cache_->GetEntryCount());
   EXPECT_EQ(net::OK, DoomAllEntries());
   ASSERT_EQ(0, cache_->GetEntryCount());
 
   // We should stop posting tasks at some point (if we post any).
   base::MessageLoop::current()->RunUntilIdle();
 
   disk_cache::Entry *entry3, *entry4;
+  entry1->Close();

[gavinp, 2013/08/26 20:36:50]

Why this?

[Philippe, 2013/08/27 11:33:30]

Good question. I needed this (and the change below) to make the CreateEntry
assertion below (line 2687) pass. Since the entry wasn't closed before the
CreateEntry(), the entry was still active which made CreateEntry() fail. Doom()
is poorly specified in the API but to me it shouldn't (even partly) replace a
Close(). What do you think?

[gavinp, 2013/08/27 15:48:02]

I think this breaks the API; it's legal and should succeed to CreateEntry()
while an entry with the same key is open and doomed.

[Philippe, 2013/08/27 16:11:21]

Ok, thanks I will address that then :)

   EXPECT_NE(net::OK, OpenEntry("third", &entry3));
   ASSERT_EQ(net::OK, CreateEntry("third", &entry3));
+  entry2->Close();
   ASSERT_EQ(net::OK, CreateEntry("fourth", &entry4));
 
   EXPECT_EQ(net::OK, DoomAllEntries());
   ASSERT_EQ(0, cache_->GetEntryCount());
 
-  entry1->Close();
-  entry2->Close();
   entry3->Doom();  // The entry should be already doomed, but this must work.
   entry3->Close();
   entry4->Close();
 
   // Now try with all references released.
   ASSERT_EQ(net::OK, CreateEntry("third", &entry1));
   ASSERT_EQ(net::OK, CreateEntry("fourth", &entry2));
   entry1->Close();
   entry2->Close();
 
@@ skipping 702 matching lines @@
   void* iter = NULL;
   size_t count = 0;
   ASSERT_TRUE(EnumerateAndMatchKeys(-1, &iter, &keys_to_match, &count));
   cache_->EndEnumeration(&iter);
 
   EXPECT_EQ(key_pool.size(), count);
   EXPECT_TRUE(keys_to_match.empty());
 }
 
 #endif  // !defined(OS_WIN)