IDBObserver: Lifetime Management: Adding Observer

third_party/WebKit/public/platform/modules/indexeddb/WebIDBDatabase.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 12 matching lines @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef WebIDBDatabase_h
 #define WebIDBDatabase_h
 
 #include "public/platform/WebBlobInfo.h"
 #include "public/platform/WebCommon.h"
 #include "public/platform/modules/indexeddb/WebIDBCursor.h"
 #include "public/platform/modules/indexeddb/WebIDBMetadata.h"
+#include "public/platform/modules/indexeddb/WebIDBObserver.h"
 #include "public/platform/modules/indexeddb/WebIDBTypes.h"
 
 namespace blink {
 
 class WebData;
 class WebIDBCallbacks;
 class WebIDBDatabaseCallbacks;
 class WebIDBKey;
 class WebIDBKeyPath;
 class WebIDBKeyRange;
+class WebIDBObserver;
 
 class WebIDBDatabase {
 public:
     virtual ~WebIDBDatabase() { }
 
     virtual void createObjectStore(long long transactionId, long long objectStoreId, const WebString& name, const WebIDBKeyPath&, bool autoIncrement) = 0;
     virtual void deleteObjectStore(long long transactionId, long long objectStoreId) = 0;
     virtual void createTransaction(long long id, WebIDBDatabaseCallbacks*, const WebVector<long long>& scope, WebIDBTransactionMode) = 0;
     virtual void close() = 0;
     virtual void versionChangeIgnored() = 0;
 
     virtual void abort(long long transactionId) = 0;
     virtual void commit(long long transactionId) = 0;
 
     virtual void createIndex(long long transactionId, long long objectStoreId, long long indexId, const WebString& name, const WebIDBKeyPath&, bool unique, bool multiEntry) = 0;
     virtual void deleteIndex(long long transactionId, long long objectStoreId, long long indexId) = 0;
 
     static const long long minimumIndexId = 30;
 
     typedef WebVector<WebIDBKey> WebIndexKeys;
 
+    virtual void observe(std::unique_ptr<WebIDBObserver>, long long transactionId) = 0;

[Marijn Kruisselbrink, 2016/06/24 00:48:09]

I think it's this API that doesn't make sense to me. WebIDBObserver is kind of
already it's own smart pointer (being nothing more than a wrapper around a
pointer to an IDBObserver). As such passing them as std::unique_ptr to
observer/unobserve doesn't make sense, you should probably just pass them by
const WebIDBObserver& and add copy and/or move constructors and assignment
operators to WebIDBObserver.

+    virtual void unobserve(std::unique_ptr<WebIDBObserver>) = 0;
     virtual void get(long long transactionId, long long objectStoreId, long long indexId, const WebIDBKeyRange&, bool keyOnly, WebIDBCallbacks*) = 0;
     virtual void getAll(long long transactionId, long long objectStoreId, long long indexId, const WebIDBKeyRange&, long long maxCount, bool keyOnly, WebIDBCallbacks*) = 0;
     virtual void put(long long transactionId, long long objectStoreId, const WebData& value, const WebVector<WebBlobInfo>&, const WebIDBKey&, WebIDBPutMode, WebIDBCallbacks*, const WebVector<long long>& indexIds, const WebVector<WebIndexKeys>&) = 0;
     virtual void setIndexKeys(long long transactionId, long long objectStoreId, const WebIDBKey&, const WebVector<long long>& indexIds, const WebVector<WebIndexKeys>&) = 0;
     virtual void setIndexesReady(long long transactionId, long long objectStoreId, const WebVector<long long>& indexIds) = 0;
     virtual void openCursor(long long transactionId, long long objectStoreId, long long indexId, const WebIDBKeyRange&, WebIDBCursorDirection, bool keyOnly, WebIDBTaskType, WebIDBCallbacks*) = 0;
     virtual void count(long long transactionId, long long objectStoreId, long long indexId, const WebIDBKeyRange&, WebIDBCallbacks*) = 0;
     virtual void deleteRange(long long transactionId, long long objectStoreId, const WebIDBKeyRange&, WebIDBCallbacks*) = 0;
     virtual void clear(long long transactionId, long long objectStoreId, WebIDBCallbacks*) = 0;
     virtual void ackReceivedBlobs(const WebVector<WebString>& uuids) = 0;
 
 protected:
     WebIDBDatabase() { }
 };
 
 } // namespace blink
 
 #endif // WebIDBDatabase_h