Line data    Source code

       1             : /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
       2             : /* vim: set ts=8 sts=2 et sw=2 tw=80: */
       3             : /* This Source Code Form is subject to the terms of the Mozilla Public
       4             :  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
       5             :  * You can obtain one at http://mozilla.org/MPL/2.0/. */
       6             : 
       7             : /**
       8             :  * A simplere nsIGlobalObject implementation that can be used to set up a new
       9             :  * global without anything interesting in it other than the JS builtins.  This
      10             :  * is safe to use on both mainthread and worker threads.
      11             :  */
      12             : 
      13             : #ifndef mozilla_dom_SimpleGlobalObject_h__
      14             : #define mozilla_dom_SimpleGlobalObject_h__
      15             : 
      16             : #include "nsIGlobalObject.h"
      17             : #include "nsWrapperCache.h"
      18             : #include "js/TypeDecls.h"
      19             : #include "nsISupportsImpl.h"
      20             : #include "nsCycleCollectionParticipant.h"
      21             : 
      22             : namespace mozilla {
      23             : namespace dom {
      24             : 
      25             : class SimpleGlobalObject : public nsIGlobalObject,
      26             :                            public nsWrapperCache
      27             : {
      28             : public:
      29             :   enum class GlobalType {
      30             :     BindingDetail, // Should only be used by DOM bindings code.
      31             :     WorkerDebuggerSandbox,
      32             :     NotSimpleGlobal // Sentinel to be used by BasicGlobalType.
      33             :   };
      34             : 
      35             :   // Create a new JS global object that can be used to do some work.  This
      36             :   // global will NOT have any DOM APIs exposed in it, will not be visible to the
      37             :   // debugger, and will not have a useful concept of principals, so don't try to
      38             :   // use it with any DOM objects.  Apart from that, running code with
      39             :   // side-effects is safe in this global.  Importantly, when you are first
      40             :   // handed this global it's guaranteed to have pristine built-ins.  The
      41             :   // corresponding nsIGlobalObject* for this global object will be a
      42             :   // SimpleGlobalObject of the type provided; JS_GetPrivate on the returned
      43             :   // JSObject* will return the SimpleGlobalObject*.
      44             :   //
      45             :   // If the provided prototype value is undefined, it is ignored.  If it's an
      46             :   // object or null, it's set as the prototype of the created global.  If it's
      47             :   // anything else, this function returns null.
      48             :   //
      49             :   // Note that creating new globals is not cheap and should not be done
      50             :   // gratuitously.  Please think carefully before you use this function.
      51             :   static JSObject* Create(GlobalType globalType,
      52             :                           JS::Handle<JS::Value> proto =
      53             :                             JS::UndefinedHandleValue);
      54             : 
      55             :   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
      56           8 :   NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS_AMBIGUOUS(SimpleGlobalObject,
      57             :                                                          nsIGlobalObject)
      58             : 
      59             :   // Gets the GlobalType of this SimpleGlobalObject.
      60           0 :   GlobalType Type() const
      61             :   {
      62           0 :     return mType;
      63             :   }
      64             : 
      65             :   // Gets the GlobalType of the SimpleGlobalObject for the given JSObject*, if
      66             :   // the given JSObject* is the global corresponding to a SimpleGlobalObject.
      67             :   // Oherwise, returns GlobalType::NotSimpleGlobal.
      68             :   static GlobalType SimpleGlobalType(JSObject* obj);
      69             : 
      70           3 :   virtual JSObject *GetGlobalJSObject() override
      71             :   {
      72           3 :     return GetWrapper();
      73             :   }
      74             : 
      75           0 :   virtual JSObject* WrapObject(JSContext* cx,
      76             :                                JS::Handle<JSObject*> aGivenProto) override
      77             :   {
      78           0 :     MOZ_CRASH("SimpleGlobalObject doesn't use DOM bindings!");
      79             :   }
      80             : 
      81             : private:
      82           1 :   SimpleGlobalObject(JSObject *global, GlobalType type)
      83           1 :     : mType(type)
      84             :   {
      85           1 :     SetWrapper(global);
      86           1 :   }
      87             : 
      88           0 :   virtual ~SimpleGlobalObject()
      89           0 :   {
      90           0 :     MOZ_ASSERT(!GetWrapperMaybeDead());
      91           0 :   }
      92             : 
      93             :   const GlobalType mType;
      94             : };
      95             : 
      96             : } // namespace dom
      97             : } // namespace mozilla
      98             : 
      99             : #endif /* mozilla_dom_SimpleGlobalObject_h__ */