[IndexedDB] Refactoring to remove ref ptrs and host transaction ids.

content/browser/indexed_db/indexed_db_cursor.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_CURSOR_H_
 #define CONTENT_BROWSER_INDEXED_DB_INDEXED_DB_CURSOR_H_
 
 #include <stdint.h>
 
 #include <memory>
 #include <string>
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
 #include "content/browser/indexed_db/indexed_db_backing_store.h"
 #include "content/browser/indexed_db/indexed_db_database.h"
 #include "content/browser/indexed_db/indexed_db_transaction.h"
 #include "content/common/indexed_db/indexed_db_key_range.h"
 #include "third_party/WebKit/public/platform/modules/indexeddb/WebIDBTypes.h"
 
 namespace content {
 
-class CONTENT_EXPORT IndexedDBCursor
-    : NON_EXPORTED_BASE(public base::RefCounted<IndexedDBCursor>) {
+class CONTENT_EXPORT IndexedDBCursor {
  public:
   IndexedDBCursor(std::unique_ptr<IndexedDBBackingStore::Cursor> cursor,
                   indexed_db::CursorType cursor_type,
                   blink::WebIDBTaskType task_type,
                   IndexedDBTransaction* transaction);
+  ~IndexedDBCursor();
 
   void Advance(uint32_t count, scoped_refptr<IndexedDBCallbacks> callbacks);
   void Continue(std::unique_ptr<IndexedDBKey> key,
                 std::unique_ptr<IndexedDBKey> primary_key,
                 scoped_refptr<IndexedDBCallbacks> callbacks);
   void PrefetchContinue(int number_to_fetch,
                         scoped_refptr<IndexedDBCallbacks> callbacks);
   leveldb::Status PrefetchReset(int used_prefetches, int unused_prefetches);
 
   const IndexedDBKey& key() const { return cursor_->key(); }
   const IndexedDBKey& primary_key() const { return cursor_->primary_key(); }
   IndexedDBValue* Value() const {
     return (cursor_type_ == indexed_db::CURSOR_KEY_ONLY) ? NULL
                                                          : cursor_->value();
   }
+
+  void RemoveCursorFromTransaction();
   void Close();
 
   leveldb::Status CursorIterationOperation(
       std::unique_ptr<IndexedDBKey> key,
       std::unique_ptr<IndexedDBKey> primary_key,
       scoped_refptr<IndexedDBCallbacks> callbacks,
       IndexedDBTransaction* transaction);
   leveldb::Status CursorAdvanceOperation(
       uint32_t count,
       scoped_refptr<IndexedDBCallbacks> callbacks,
       IndexedDBTransaction* transaction);
   leveldb::Status CursorPrefetchIterationOperation(
       int number_to_fetch,
       scoped_refptr<IndexedDBCallbacks> callbacks,
       IndexedDBTransaction* transaction);
 
  private:
-  friend class base::RefCounted<IndexedDBCursor>;
-
-  ~IndexedDBCursor();
-
   blink::WebIDBTaskType task_type_;
   indexed_db::CursorType cursor_type_;
-  const scoped_refptr<IndexedDBTransaction> transaction_;
+
+  // We rely on the transaction calling Close() to clear this.
+  IndexedDBTransaction* transaction_;
 
   // Must be destroyed before transaction_.

[cmumford, 2016/12/01 19:14:51]

Should Close() assert that cursor_ is null?

[dmurph, 2016/12/01 21:12:23]

No, as the IndexedDBTransaction calls it in CloseAllCursors(). So we need it to
reset the cursor in that case.

   std::unique_ptr<IndexedDBBackingStore::Cursor> cursor_;
   // Must be destroyed before transaction_.
   std::unique_ptr<IndexedDBBackingStore::Cursor> saved_cursor_;
 
   bool closed_;
 
+  base::WeakPtrFactory<IndexedDBCursor> ptr_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(IndexedDBCursor);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_INDEXED_DB_INDEXED_DB_CURSOR_H_