Align IndexedDB metadata rollback on transaction abort to spec.

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

 /*
  * Copyright (C) 2012 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 15 matching lines @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef IDBMetadata_h
 #define IDBMetadata_h
 
 #include "modules/indexeddb/IDBKeyPath.h"
 #include "public/platform/modules/indexeddb/WebIDBMetadata.h"
 #include "wtf/Allocator.h"
 #include "wtf/HashMap.h"
+#include "wtf/RefCounted.h"
+#include "wtf/RefPtr.h"
 #include "wtf/text/StringHash.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
 
-struct IDBIndexMetadata {
-    DISALLOW_NEW_EXCEPT_PLACEMENT_NEW();
-    IDBIndexMetadata() { }
-    IDBIndexMetadata(const String& name, int64_t id, const IDBKeyPath& keyPath, bool unique, bool multiEntry)
-        : name(name)
-        , id(id)
-        , keyPath(keyPath)
-        , unique(unique)
-        , multiEntry(multiEntry) { }
+// The lifecycle of the IndexedDB metadata objects defined below is managed by
+// reference counting (RefPtr). We don't have to worry about cycles because
+// these objects form a tree with the hierarch shown below.
+//     IDBDatabaseMetadata -> IDBObjectStoreMetadata -> IDBIndexMetadata
+
+class IDBIndexMetadata : public RefCounted<IDBIndexMetadata> {
+    USING_FAST_MALLOC(IDBIndexMetadata);
+
+public:
+    IDBIndexMetadata();
+    IDBIndexMetadata(const String& name, int64_t id, const IDBKeyPath&, bool unique, bool multiEntry);
+
     String name;
     int64_t id;
     IDBKeyPath keyPath;
     bool unique;
     bool multiEntry;
 
     static constexpr int64_t InvalidId = -1;
 };
 
-struct IDBObjectStoreMetadata {
-    DISALLOW_NEW_EXCEPT_PLACEMENT_NEW();
-    IDBObjectStoreMetadata() { }
-    IDBObjectStoreMetadata(const String& name, int64_t id, const IDBKeyPath& keyPath, bool autoIncrement, int64_t maxIndexId)
-        : name(name)
-        , id(id)
-        , keyPath(keyPath)
-        , autoIncrement(autoIncrement)
-        , maxIndexId(maxIndexId)
-    {
-    }
+class IDBObjectStoreMetadata : public RefCounted<IDBObjectStoreMetadata> {
+    USING_FAST_MALLOC(IDBObjectStoreMetadata);
+
+public:
+    IDBObjectStoreMetadata();
+    IDBObjectStoreMetadata(const String& name, int64_t id, const IDBKeyPath&, bool autoIncrement, int64_t maxIndexId);
+
+    // Creates a deep copy of the object metadata, which includes copies of index metadata items.
+    RefPtr<IDBObjectStoreMetadata> createCopy() const;
+
     String name;
     int64_t id;
     IDBKeyPath keyPath;
     bool autoIncrement;
     int64_t maxIndexId;
 
     static constexpr int64_t InvalidId = -1;
 
-    typedef HashMap<int64_t, IDBIndexMetadata> IndexMap;
+    using IndexMap = HashMap<int64_t, RefPtr<IDBIndexMetadata>>;
     IndexMap indexes;
 };
 
-struct IDBDatabaseMetadata {
+struct MODULES_EXPORT IDBDatabaseMetadata {
     DISALLOW_NEW();
+
+public:
     // FIXME: These can probably be collapsed into 0.
     enum {
         NoVersion = -1,
         DefaultVersion = 0
     };
 
-    typedef HashMap<int64_t, IDBObjectStoreMetadata> ObjectStoreMap;
-
-    IDBDatabaseMetadata()
-        : version(NoVersion)
-    {
-    }
-
-    IDBDatabaseMetadata(const String& name, int64_t id, int64_t version, int64_t maxObjectStoreId)
-        : name(name)
-        , id(id)
-        , version(version)
-        , maxObjectStoreId(maxObjectStoreId)
-    {
-    }
+    IDBDatabaseMetadata();
+    IDBDatabaseMetadata(const String& name, int64_t id, int64_t version, int64_t maxObjectStoreId);
 
     explicit IDBDatabaseMetadata(const WebIDBMetadata&);
 
     String name;
     int64_t id;
     int64_t version;
     int64_t maxObjectStoreId;
 
+    using ObjectStoreMap = HashMap<int64_t, RefPtr<IDBObjectStoreMetadata>>;

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

Nit: Per style guide (google, not overridden by chromium or blink),
usings/typedefs go at the start of a public (etc) section of the definition.

https://google.github.io/styleguide/cppguide.html#Declaration_Order

May want to re-order in the above classes too.

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

Done.

I also moved "using" in IDBObjectStore.h and IDBTransaction.h

     ObjectStoreMap objectStores;
 };
 
 } // namespace blink
 
 #endif // IDBMetadata_h