IndexedDB: Prevent store/index deletion from racing ahead of use

content/browser/indexed_db/indexed_db_database.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 CONTENT_BROWSER_INDEXED_DB_INDEXED_DB_DATABASE_H_
 #define CONTENT_BROWSER_INDEXED_DB_INDEXED_DB_DATABASE_H_
 
 #include <list>
 #include <map>
 #include <string>
@@ skipping 157 matching lines @@
   // Number of open calls that are blocked on other connections.
   size_t PendingOpenCount() const;
   // Number of pending upgrades (0 or 1). Also included in ConnectionCount().
   size_t PendingUpgradeCount() const;
   // Number of running upgrades (0 or 1). Also included in ConnectionCount().
   size_t RunningUpgradeCount() const;
   // Number of pending deletes, blocked on other connections.
   size_t PendingDeleteCount() const;
 
   // Asynchronous tasks scheduled within transactions:
-  void CreateObjectStoreOperation(
-      const IndexedDBObjectStoreMetadata& object_store_metadata,
-      IndexedDBTransaction* transaction);
   void CreateObjectStoreAbortOperation(int64 object_store_id,
                                        IndexedDBTransaction* transaction);
   void DeleteObjectStoreOperation(
-      const IndexedDBObjectStoreMetadata& object_store_metadata,
+      int64 object_store_id,

[jsbell, 2014/05/19 22:07:08]

Metadata should be snapshotted asynchronously, so ID is sufficient here.

c/o a race found by running transaction-basics.html a 2500 times; would DCHECK
fail about 0.5% of the time. The failure case was 
deleteIndex/deleteObjectStore/abort - the abort would first restore the
objectStore but with metadata including the index, and second restoring the
index - *boom*.

       IndexedDBTransaction* transaction);
   void DeleteObjectStoreAbortOperation(
       const IndexedDBObjectStoreMetadata& object_store_metadata,
       IndexedDBTransaction* transaction);
   void VersionChangeOperation(int64 version,
                               scoped_refptr<IndexedDBCallbacks> callbacks,
                               scoped_ptr<IndexedDBConnection> connection,
                               IndexedDBTransaction* transaction);
   void VersionChangeAbortOperation(const base::string16& previous_version,
                                    int64 previous_int_version,
                                    IndexedDBTransaction* transaction);
-  void CreateIndexOperation(int64 object_store_id,
-                            const IndexedDBIndexMetadata& index_metadata,
-                            IndexedDBTransaction* transaction);
   void DeleteIndexOperation(int64 object_store_id,
-                            const IndexedDBIndexMetadata& index_metadata,
+                            int64 index_id,

[jsbell, 2014/05/19 22:07:08]

Metadata should be snapshotted asynchronously, so ID is sufficient here.

                             IndexedDBTransaction* transaction);
   void CreateIndexAbortOperation(int64 object_store_id,
                                  int64 index_id,
                                  IndexedDBTransaction* transaction);
   void DeleteIndexAbortOperation(int64 object_store_id,
                                  const IndexedDBIndexMetadata& index_metadata,
                                  IndexedDBTransaction* transaction);
   void GetOperation(int64 object_store_id,
                     int64 index_id,
                     scoped_ptr<IndexedDBKeyRange> key_range,
@@ skipping 83 matching lines @@
   typedef std::list<PendingDeleteCall*> PendingDeleteCallList;
   PendingDeleteCallList pending_delete_calls_;
 
   typedef list_set<IndexedDBConnection*> ConnectionSet;
   ConnectionSet connections_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_INDEXED_DB_INDEXED_DB_DATABASE_H_