Wrap large IndexedDB values into Blobs before writing to LevelDB.

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
  *     notice, this list of conditions and the following disclaimer in the
  *     documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef IDBTransaction_h
 #define IDBTransaction_h
 
+#include <memory>
+
 #include "core/dom/ContextLifecycleObserver.h"
 #include "core/dom/DOMStringList.h"
 #include "core/events/EventListener.h"
 #include "modules/EventModules.h"
 #include "modules/EventTargetModules.h"
 #include "modules/ModulesExport.h"
 #include "modules/indexeddb/IDBMetadata.h"
 #include "modules/indexeddb/IndexedDB.h"
 #include "platform/bindings/ActiveScriptWrappable.h"
 #include "platform/heap/Handle.h"
+#include "platform/wtf/Deque.h"
 #include "platform/wtf/HashSet.h"
 #include "platform/wtf/Vector.h"
 #include "public/platform/modules/indexeddb/WebIDBDatabase.h"
 #include "public/platform/modules/indexeddb/WebIDBTypes.h"
 
 namespace blink {
 
 class DOMException;
 class ExecutionContext;
 class ExceptionState;
 class IDBDatabase;
 class IDBIndex;
 class IDBObjectStore;
 class IDBOpenDBRequest;
 class IDBRequest;
+class IDBRequestQueueItem;
 class ScriptState;
 
 class MODULES_EXPORT IDBTransaction final
     : public EventTargetWithInlineData,
       public ActiveScriptWrappable<IDBTransaction>,
       public ContextLifecycleObserver {
   USING_GARBAGE_COLLECTED_MIXIN(IDBTransaction);
   DEFINE_WRAPPERTYPEINFO();
 
  public:
@@ skipping 34 matching lines @@
   const String& mode() const;
   DOMStringList* objectStoreNames() const;
   IDBDatabase* db() const { return database_.Get(); }
   DOMException* error() const { return error_; }
   IDBObjectStore* objectStore(const String& name, ExceptionState&);
   void abort(ExceptionState&);
 
   void RegisterRequest(IDBRequest*);
   void UnregisterRequest(IDBRequest*);
 
+  // True if this transaction has at least one request whose result is being
+  // post-processed.
+  //
+  // While this is true, new results must be queued using QueueResult().

[jsbell, 2017/05/15 23:37:38]

nit: EnqueueResult

[pwnall, 2017/05/19 18:27:35]

Done.

+  inline bool HasQueuedResults() const { return !result_queue_.empty(); }
+  void EnqueueResult(std::unique_ptr<IDBRequestQueueItem> result);
+  // Called when a result's post-processing has completed.
+  void OnResultReady();
+
   // The methods below are called right before the changes are applied to the
   // database's metadata. We use this unusual sequencing because some of the
   // methods below need to access the metadata values before the change, and
   // following the same lifecycle for all methods makes the code easier to
   // reason about.
   void ObjectStoreCreated(const String& name, IDBObjectStore*);
   void ObjectStoreDeleted(const int64_t object_store_id, const String& name);
   void ObjectStoreRenamed(const String& old_name, const String& new_name);
   // Called when deleting an index whose IDBIndex had been created.
   void IndexDeleted(IDBIndex*);
@@ skipping 87 matching lines @@
   // because object stores cannot be renamed in non-versionchange
   // transactions.
   const HashSet<String> scope_;
 
   State state_ = kActive;
   bool has_pending_activity_ = true;
   Member<DOMException> error_;
 
   HeapListHashSet<Member<IDBRequest>> request_list_;
 
+  // The IDBRequest results whose events have not fired yet.

[jsbell, 2017/05/15 23:37:38]

nit: enqueued, not fired

[pwnall, 2017/05/19 18:27:35]

Done.

+  //
+  // When a result requires post-processing, such as large value unwrapping, all
+  // the results that arrive during the post-processing phase are queued up.
+  // This guarantees that result events are fired in the order in which the
+  // requests were performed, as prescribed by the IndexedDB specification.
+  Deque<std::unique_ptr<IDBRequestQueueItem>> result_queue_;
+
 #if DCHECK_IS_ON()
   bool finish_called_ = 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.
   //
@@ skipping 31 matching lines @@
   // This does not include a snapshot of the database's object store / index
   // metadata.
   //
   // Only valid for versionchange transactions.
   IDBDatabaseMetadata old_database_metadata_;
 };
 
 }  // namespace blink
 
 #endif  // IDBTransaction_h