The Tor Browser: dom/events/JSEventHandler.h@97036ab72558 (annotated)

dom/events/JSEventHandler.h@97036ab72558 (annotated)

dom/events/JSEventHandler.h

Tue, 06 Jan 2015 21:39:09 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Tue, 06 Jan 2015 21:39:09 +0100
branch: TOR_BUG_9701
changeset 8: 97036ab72558
permissions: -rw-r--r--

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #ifndef mozilla_JSEventHandler_h_
 #define mozilla_JSEventHandler_h_
 #include "mozilla/Attributes.h"
 #include "mozilla/MemoryReporting.h"
 #include "mozilla/dom/EventHandlerBinding.h"
 #include "nsCOMPtr.h"
 #include "nsCycleCollectionParticipant.h"
 #include "nsIAtom.h"
 #include "nsIDOMKeyEvent.h"
 #include "nsIDOMEventListener.h"
 #include "nsIScriptContext.h"
 namespace mozilla {
 class TypedEventHandler
 {
 public:
   enum HandlerType
   {
     eUnset = 0,
     eNormal = 0x1,
     eOnError = 0x2,
     eOnBeforeUnload = 0x3,
     eTypeBits = 0x3
   };
   TypedEventHandler()
     : mBits(0)
   {
   }
   TypedEventHandler(dom::EventHandlerNonNull* aHandler)
   {
     Assign(aHandler, eNormal);
   }
   TypedEventHandler(dom::OnErrorEventHandlerNonNull* aHandler)
   {
     Assign(aHandler, eOnError);
   }
   TypedEventHandler(dom::OnBeforeUnloadEventHandlerNonNull* aHandler)
   {
     Assign(aHandler, eOnBeforeUnload);
   }
   TypedEventHandler(const TypedEventHandler& aOther)
   {
     if (aOther.HasEventHandler()) {
       // Have to make sure we take our own ref
       Assign(aOther.Ptr(), aOther.Type());
     } else {
       mBits = 0;
     }
   }
   ~TypedEventHandler()
   {
     ReleaseHandler();
   }
   HandlerType Type() const
   {
     return HandlerType(mBits & eTypeBits);
   }
   bool HasEventHandler() const
   {
     return !!Ptr();
   }
   void SetHandler(const TypedEventHandler& aHandler)
   {
     if (aHandler.HasEventHandler()) {
       ReleaseHandler();
       Assign(aHandler.Ptr(), aHandler.Type());
     } else {
       ForgetHandler();
     }
   }
   dom::EventHandlerNonNull* NormalEventHandler() const
   {
     MOZ_ASSERT(Type() == eNormal && Ptr());
     return reinterpret_cast<dom::EventHandlerNonNull*>(Ptr());
   }
   void SetHandler(dom::EventHandlerNonNull* aHandler)
   {
     ReleaseHandler();
     Assign(aHandler, eNormal);
   }
   dom::OnBeforeUnloadEventHandlerNonNull* OnBeforeUnloadEventHandler() const
   {
     MOZ_ASSERT(Type() == eOnBeforeUnload);
     return reinterpret_cast<dom::OnBeforeUnloadEventHandlerNonNull*>(Ptr());
   }
   void SetHandler(dom::OnBeforeUnloadEventHandlerNonNull* aHandler)
   {
     ReleaseHandler();
     Assign(aHandler, eOnBeforeUnload);
   }
   dom::OnErrorEventHandlerNonNull* OnErrorEventHandler() const
   {
     MOZ_ASSERT(Type() == eOnError);
     return reinterpret_cast<dom::OnErrorEventHandlerNonNull*>(Ptr());
   }
   void SetHandler(dom::OnErrorEventHandlerNonNull* aHandler)
   {
     ReleaseHandler();
     Assign(aHandler, eOnError);
   }
   dom::CallbackFunction* Ptr() const
   {
     // Have to cast eTypeBits so we don't have to worry about
     // promotion issues after the bitflip.
     return reinterpret_cast<dom::CallbackFunction*>(mBits &
                                                       ~uintptr_t(eTypeBits));
   }
   void ForgetHandler()
   {
     ReleaseHandler();
     mBits = 0;
   }
   bool operator==(const TypedEventHandler& aOther) const
   {
     return
       Ptr() && aOther.Ptr() &&
       Ptr()->CallbackPreserveColor() == aOther.Ptr()->CallbackPreserveColor();
   }
 private:
   void operator=(const TypedEventHandler&) MOZ_DELETE;
   void ReleaseHandler()
   {
     nsISupports* ptr = Ptr();
     NS_IF_RELEASE(ptr);
   }
   void Assign(nsISupports* aHandler, HandlerType aType)
   {
     MOZ_ASSERT(aHandler, "Must have handler");
     NS_ADDREF(aHandler);
     mBits = uintptr_t(aHandler) | uintptr_t(aType);
   }
   uintptr_t mBits;
 };
 /**
  * Implemented by script event listeners. Used to retrieve the script object
  * corresponding to the event target and the handler itself.
  *
  * Note, mTarget is a raw pointer and the owner of the JSEventHandler object
  * is expected to call Disconnect()!
  */
 #define NS_JSEVENTHANDLER_IID \
 { 0x4f486881, 0x1956, 0x4079, \
   { 0x8c, 0xa0, 0xf3, 0xbd, 0x60, 0x5c, 0xc2, 0x79 } }
 class JSEventHandler : public nsIDOMEventListener
 {
 public:
   NS_DECLARE_STATIC_IID_ACCESSOR(NS_JSEVENTHANDLER_IID)
   JSEventHandler(nsISupports* aTarget, nsIAtom* aType,
                  const TypedEventHandler& aTypedHandler);
   virtual ~JSEventHandler();
   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
   // nsIDOMEventListener interface
   NS_DECL_NSIDOMEVENTLISTENER
   nsISupports* GetEventTarget() const
   {
     return mTarget;
   }
   void Disconnect()
   {
     mTarget = nullptr;
   }
   const TypedEventHandler& GetTypedEventHandler() const
   {
     return mTypedHandler;
   }
   void ForgetHandler()
   {
     mTypedHandler.ForgetHandler();
   }
   nsIAtom* EventName() const
   {
     return mEventName;
   }
   // Set a handler for this event listener.  The handler must already
   // be bound to the right target.
   void SetHandler(const TypedEventHandler& aTypedHandler)
   {
     mTypedHandler.SetHandler(aTypedHandler);
   }
   void SetHandler(dom::EventHandlerNonNull* aHandler)
   {
     mTypedHandler.SetHandler(aHandler);
   }
   void SetHandler(dom::OnBeforeUnloadEventHandlerNonNull* aHandler)
   {
     mTypedHandler.SetHandler(aHandler);
   }
   void SetHandler(dom::OnErrorEventHandlerNonNull* aHandler)
   {
     mTypedHandler.SetHandler(aHandler);
   }
   size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const
   {
     return 0;
     // Measurement of the following members may be added later if DMD finds it
     // is worthwhile:
     // - mTarget
     //
     // The following members are not measured:
     // - mTypedHandler: may be shared with others
     // - mEventName: shared with others
   }
   size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf)
   {
     return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
   }
   NS_DECL_CYCLE_COLLECTION_SKIPPABLE_CLASS(JSEventHandler)
   bool IsBlackForCC();
 protected:
   nsISupports* mTarget;
   nsCOMPtr<nsIAtom> mEventName;
   TypedEventHandler mTypedHandler;
 };
 NS_DEFINE_STATIC_IID_ACCESSOR(JSEventHandler, NS_JSEVENTHANDLER_IID)
 } // namespace mozilla
 /**
  * Factory function.  aHandler must already be bound to aTarget.
  * aContext is allowed to be null if aHandler is already set up.
  */
 nsresult NS_NewJSEventHandler(nsISupports* aTarget,
                               nsIAtom* aType,
                               const mozilla::TypedEventHandler& aTypedHandler,
                               mozilla::JSEventHandler** aReturn);
 #endif // mozilla_JSEventHandler_h_

The Tor Browser / annotate

dom/events/JSEventHandler.h@97036ab72558 (annotated)

dom/events/JSEventHandler.h