Minor IndexedDB refactorings.

third_party/WebKit/Source/modules/indexeddb/IDBTransaction.h

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 30 matching lines @@
 #include "public/platform/modules/indexeddb/WebIDBTypes.h"
 #include "wtf/HashSet.h"
 
 namespace blink {
 
 class DOMException;
 class ExceptionState;
 class IDBDatabase;
 class IDBObjectStore;
 class IDBOpenDBRequest;
-struct IDBObjectStoreMetadata;
 
 class MODULES_EXPORT IDBTransaction final
     : public EventTargetWithInlineData
     , public ActiveScriptWrappable
     , public ActiveDOMObject {
     USING_GARBAGE_COLLECTED_MIXIN(IDBTransaction);
     DEFINE_WRAPPERTYPEINFO();
 public:
-    static IDBTransaction* create(ScriptState*, int64_t, const HashSet<String>& objectStoreNames, WebIDBTransactionMode, IDBDatabase*);
-    static IDBTransaction* create(ScriptState*, int64_t, IDBDatabase*, IDBOpenDBRequest*, const IDBDatabaseMetadata& previousMetadata);
+    static IDBTransaction* createNonVersionChange(ScriptState*, int64_t, const HashSet<String>& objectStoreNames, WebIDBTransactionMode, IDBDatabase*);
+    static IDBTransaction* createVersionChange(ScriptState*, int64_t, IDBDatabase*, IDBOpenDBRequest*, const IDBDatabaseMetadata& oldMetadata);
     ~IDBTransaction() override;
     DECLARE_VIRTUAL_TRACE();
 
     static WebIDBTransactionMode stringToMode(const String&);
 
     // When the connection is closed backend will be 0.
     WebIDBDatabase* backendDB() const;
 
     int64_t id() const { return m_id; }
     bool isActive() const { return m_state == Active; }
@@ skipping 37 matching lines @@
 
 protected:
     // EventTarget
     DispatchEventResult dispatchEventInternal(Event*) override;
 
 private:
     IDBTransaction(ScriptState*, int64_t, const HashSet<String>&, WebIDBTransactionMode, IDBDatabase*, IDBOpenDBRequest*, const IDBDatabaseMetadata&);
 
     void enqueueEvent(Event*);
 
+    // Called when a transaction is aborted.
+    void abortOutstandingRequests();
+    void revertDatabaseMetadata();
+
+    // Called when a transaction is completed (committed or aborted).
+    void finish();

[cmumford, 2016/09/19 23:26:48]

If the transaction has already finished then this function should be named
"finished" to avoid confusion.

[pwnall, 2016/09/20 09:11:15]

Done.

+
     enum State {
         Inactive, // Created or started, but not in an event callback
         Active, // Created or started, in creation scope or an event callback
         Finishing, // In the process of aborting or completing.
         Finished, // No more events will fire and no new requests may be filed.
     };
 
     const int64_t m_id;
     Member<IDBDatabase> m_database;
-    const HashSet<String> m_objectStoreNames;
+    const HashSet<String> m_scope;

[cmumford, 2016/09/19 23:26:48]

You may want to add a comment above m_scope.

[pwnall, 2016/09/20 09:11:15]

Done.
Thank you! That's a very good point!

     Member<IDBOpenDBRequest> m_openDBRequest;
     const WebIDBTransactionMode m_mode;
     State m_state = Active;
     bool m_hasPendingActivity = true;
     bool m_contextStopped = false;
     Member<DOMException> m_error;
 
     HeapListHashSet<Member<IDBRequest>> m_requestList;
 
-    typedef HeapHashMap<String, Member<IDBObjectStore>> IDBObjectStoreMap;
+#if DCHECK_IS_ON()
+    bool m_finishCalled = false;
+#endif // DCHECK_IS_ON()
+
+    // Caches the IDBObjectStore instances returned by the objectStore() method.
+    //
+    // The spec requires that a transaction's objectStore() returns the same
+    // IDBObjectStore instance for a specific store, so this cache is necessary
+    // for correctness.
+    //
+    // objectStore() throws for completed/aborted transactions, so this is not
+    // used after a transaction is finished, and can be cleared.
+    using IDBObjectStoreMap = HeapHashMap<String, Member<IDBObjectStore>>;
     IDBObjectStoreMap m_objectStoreMap;
 
     // Used to mark stores created in an aborted upgrade transaction as
     // deleted.
     HeapHashSet<Member<IDBObjectStore>> m_createdObjectStores;
 
     // Used to notify object stores (which are no longer in m_objectStoreMap)
     // when the transaction is finished.
     HeapHashSet<Member<IDBObjectStore>> m_deletedObjectStores;
 
     // Holds stores created, deleted, or used during upgrade transactions to
     // reset metadata in case of abort.
     HeapHashMap<Member<IDBObjectStore>, IDBObjectStoreMetadata> m_objectStoreCleanupMap;
-    IDBDatabaseMetadata m_previousMetadata;
+
+    IDBDatabaseMetadata m_oldDatabaseMetadata;
 };
 
 } // namespace blink
 
 #endif // IDBTransaction_h