Bindings: Manage multiple DOMWrapperWorlds for worklets

third_party/WebKit/Source/bindings/core/v8/DOMWrapperWorld.h

 /*
  * Copyright (C) 2009 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 43 matching lines @@
   // Per-thread global identifiers for DOMWrapperWorld.
   enum WorldId {
     InvalidWorldId = -1,
     MainWorldId = 0,
 
     // Embedder isolated worlds can use IDs in [1, 1<<29).
     EmbedderWorldIdLimit = (1 << 29),
     DocumentXMLTreeViewerWorldId,
     IsolatedWorldIdLimit,
 
-    // TODO(nhiroki): Dynamically allocate a world id for the following worlds
-    // instead of a fixed value (https://crbug.com/697622).
-    GarbageCollectorWorldId,
-    RegExpWorldId,
-    TestingWorldId,
-    WorkerWorldId,
+    // Other worlds can use IDs after IsolatedWorldIdLimit. Don't manually pick
+    // up an ID from this range. generateWorldIdForType() picks it up on behalf
+    // of you.
   };
 
   enum class WorldType {
     Main,
     Isolated,
     GarbageCollector,
     RegExp,
     Testing,
     Worker,
   };
@@ skipping 60 matching lines @@
   void registerDOMObjectHolder(v8::Isolate*, T*, v8::Local<v8::Value>);
 
  private:
   DOMWrapperWorld(v8::Isolate*, WorldType, int worldId);
 
   static void weakCallbackForDOMObjectHolder(
       const v8::WeakCallbackInfo<DOMObjectHolderBase>&);
   void registerDOMObjectHolderInternal(std::unique_ptr<DOMObjectHolderBase>);
   void unregisterDOMObjectHolder(DOMObjectHolderBase*);
 
   static unsigned s_numberOfNonMainWorldsInMainThread;

[peria, 2017/03/14 09:52:46]

optional: Can this static variable be replaced with isolatedWorldMap().size() +
worldMap().size() if its performance is acceptable and it is accessed only in
the main thread?

[nhiroki, 2017/03/14 10:58:28]

It'd be feasible. I'll work on it in a follow-up CL that merges
isolatedWorldMap() into worldMap().

 
-  // Returns an identifier for a given world type. This must not call for
+  // Returns an identifier for a given world type. This must not be called for
   // WorldType::IsolatedWorld because an identifier for the world is given from
   // out of DOMWrapperWorld.
-  static int getWorldIdForType(WorldType);
+  static int generateWorldIdForType(WorldType);
 
   const WorldType m_worldType;
   const int m_worldId;
   std::unique_ptr<DOMDataStore> m_domDataStore;
   HashSet<std::unique_ptr<DOMObjectHolderBase>> m_domObjectHolders;
 };
 
 }  // namespace blink
 
 #endif  // DOMWrapperWorld_h