Align IndexedDB metadata rollback on transaction abort to spec.

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

Index: third_party/WebKit/Source/modules/indexeddb/IDBObjectStore.h
diff --git a/third_party/WebKit/Source/modules/indexeddb/IDBObjectStore.h b/third_party/WebKit/Source/modules/indexeddb/IDBObjectStore.h
index 0bc4ab1ca37fb3cead3e7efe1a0b934ef014b85e..cd5e55e7db0c8575058c10b717e6e2b4d1177cb4 100644
--- a/third_party/WebKit/Source/modules/indexeddb/IDBObjectStore.h
+++ b/third_party/WebKit/Source/modules/indexeddb/IDBObjectStore.h
@@ -39,7 +39,6 @@
 #include "public/platform/modules/indexeddb/WebIDBCursor.h"
 #include "public/platform/modules/indexeddb/WebIDBDatabase.h"
 #include "public/platform/modules/indexeddb/WebIDBTypes.h"
-#include "wtf/PassRefPtr.h"
 #include "wtf/RefPtr.h"
 #include "wtf/text/WTFString.h"
 
@@ -52,14 +51,14 @@ class ExceptionState;
 class IDBObjectStore final : public GarbageCollectedFinalized<IDBObjectStore>, public ScriptWrappable {
     DEFINE_WRAPPERTYPEINFO();
 public:
-    static IDBObjectStore* create(const IDBObjectStoreMetadata& metadata, IDBTransaction* transaction)
+    static IDBObjectStore* create(RefPtr<IDBObjectStoreMetadata> metadata, IDBTransaction* transaction)
     {
-        return new IDBObjectStore(metadata, transaction);
+        return new IDBObjectStore(std::move(metadata), transaction);
     }
     ~IDBObjectStore() { }
     DECLARE_TRACE();
 
-    const IDBObjectStoreMetadata& metadata() const { return m_metadata; }
+    const IDBObjectStoreMetadata& metadata() const { return *m_metadata; }
     const IDBKeyPath& idbKeyPath() const { return metadata().keyPath; }
 
     // Implement the IDBObjectStore IDL
@@ -101,33 +100,57 @@ public:
 
     void markDeleted();
     bool isDeleted() const { return m_deleted; }
-    void abort();
-    void transactionFinished();
 
-    void setMetadata(const IDBObjectStoreMetadata& metadata) { m_metadata = metadata; }
+    // Clears the cache used to implement the index() method.
+    //
+    // This should be called when the store's transaction clears its reference
+    // to this IDBObjectStore instance, so the store can clear its references to
+    // IDBIndex instances. This way, Oilpan can garbage-collect the instances
+    // that are not referenced in JavaScript.
+    //
+    // For most stores, the condition above is met when the transaction
+    /// finishes. The exception is stores that are created and deleted in the

[jsbell, 2016/09/26 22:23:40]

Nit: extra /

[pwnall, 2016/09/27 00:12:19]

Done.

+    // same transaction. Those stores will remain marked for deletion even if
+    // the transaction aborts, so the transaction can forget about them (and
+    // clear their index caches) right when they are deleted.
+    void clearIndexCache();
+
+    // Sets the object store's metadata to a previous version.
+    //
+    // The reverting process includes reverting the metadata for the IDBIndex
+    // instances that are still tracked by the store. It does not revert the
+    // IDBIndex metadata for indexes that were deleted in this transaction.
+    //
+    // Used when a versionchange transaction is aborted.
+    void revertMetadata(RefPtr<IDBObjectStoreMetadata> previousMetadata);
+    // This relies on the changes made by revertMetadata().
+    void revertDeletedIndexMetadata(IDBIndex& deletedIndex);
 
     // Used by IDBIndex::setName:
     bool containsIndex(const String& name) const
     {
         return findIndexId(name) != IDBIndexMetadata::InvalidId;
     }
-    void indexRenamed(int64_t indexId, const String& newName);
+    void renameIndex(int64_t indexId, const String& newName);
 
     WebIDBDatabase* backendDB() const;
 
 private:
-    IDBObjectStore(const IDBObjectStoreMetadata&, IDBTransaction*);
+    IDBObjectStore(RefPtr<IDBObjectStoreMetadata>, IDBTransaction*);
 
     IDBIndex* createIndex(ScriptState*, const String& name, const IDBKeyPath&, const IDBIndexParameters&, ExceptionState&);
     IDBRequest* put(ScriptState*, WebIDBPutMode, IDBAny* source, const ScriptValue&, const ScriptValue& key, ExceptionState&);
 
     int64_t findIndexId(const String& name) const;
 
-    IDBObjectStoreMetadata m_metadata;
+    // The IDBObjectStoreMetadata is shared with the object store map in the
+    // database's metadata.
+    RefPtr<IDBObjectStoreMetadata> m_metadata;
     Member<IDBTransaction> m_transaction;
     bool m_deleted = false;
 
     // Caches the IDBIndex instances returned by the index() method.
+    //
     // The spec requires that an object store's index() returns the same
     // IDBIndex instance for a specific index, so this cache is necessary
     // for correctness.
@@ -137,9 +160,9 @@ private:
     using IDBIndexMap = HeapHashMap<String, Member<IDBIndex>>;
     IDBIndexMap m_indexMap;
 
-    // Used to mark indexes created in an aborted upgrade transaction as
-    // deleted.
-    HeapHashSet<Member<IDBIndex>> m_createdIndexes;
+#if DCHECK_IS_ON()
+    bool m_clearIndexCacheCalled = false;
+#endif // DCHECK_IS_ON()
 };
 
 } // namespace blink