gecko/dom/base/nsIJSEventListener.h
Olli Pettay 0d3a371bfe Bug 916685, no need to store empty event handlers, r=bz
--HG--
extra : rebase_source : 4a1b7e5e177744438f6bb59d58b0e2f6e2fe3b5c
2013-09-26 23:01:19 +03:00

298 lines
7.4 KiB
C++

/* -*- Mode: C++; tab-width: 2; 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 nsIJSEventListener_h__
#define nsIJSEventListener_h__
#include "nsIScriptContext.h"
#include "xpcpublic.h"
#include "nsIDOMEventListener.h"
#include "nsIAtom.h"
#include "mozilla/MemoryReporting.h"
#include "mozilla/dom/EventHandlerBinding.h"
#define NS_IJSEVENTLISTENER_IID \
{ 0x92f9212b, 0xa6aa, 0x4867, \
{ 0x93, 0x8a, 0x56, 0xbe, 0x17, 0x67, 0x4f, 0xd4 } }
class nsEventHandler
{
public:
typedef mozilla::dom::EventHandlerNonNull EventHandlerNonNull;
typedef mozilla::dom::BeforeUnloadEventHandlerNonNull
BeforeUnloadEventHandlerNonNull;
typedef mozilla::dom::OnErrorEventHandlerNonNull OnErrorEventHandlerNonNull;
typedef mozilla::dom::CallbackFunction CallbackFunction;
enum HandlerType {
eUnset = 0,
eNormal = 0x1,
eOnError = 0x2,
eOnBeforeUnload = 0x3,
eTypeBits = 0x3
};
nsEventHandler() :
mBits(0)
{}
nsEventHandler(EventHandlerNonNull* aHandler)
{
Assign(aHandler, eNormal);
}
nsEventHandler(OnErrorEventHandlerNonNull* aHandler)
{
Assign(aHandler, eOnError);
}
nsEventHandler(BeforeUnloadEventHandlerNonNull* aHandler)
{
Assign(aHandler, eOnBeforeUnload);
}
nsEventHandler(const nsEventHandler& aOther)
{
if (aOther.HasEventHandler()) {
// Have to make sure we take our own ref
Assign(aOther.Ptr(), aOther.Type());
} else {
mBits = 0;
}
}
~nsEventHandler()
{
ReleaseHandler();
}
HandlerType Type() const {
return HandlerType(mBits & eTypeBits);
}
bool HasEventHandler() const
{
return !!Ptr();
}
void SetHandler(const nsEventHandler& aHandler)
{
if (aHandler.HasEventHandler()) {
ReleaseHandler();
Assign(aHandler.Ptr(), aHandler.Type());
} else {
ForgetHandler();
}
}
EventHandlerNonNull* EventHandler() const
{
MOZ_ASSERT(Type() == eNormal && Ptr());
return reinterpret_cast<EventHandlerNonNull*>(Ptr());
}
void SetHandler(EventHandlerNonNull* aHandler)
{
ReleaseHandler();
Assign(aHandler, eNormal);
}
BeforeUnloadEventHandlerNonNull* BeforeUnloadEventHandler() const
{
MOZ_ASSERT(Type() == eOnBeforeUnload);
return reinterpret_cast<BeforeUnloadEventHandlerNonNull*>(Ptr());
}
void SetHandler(BeforeUnloadEventHandlerNonNull* aHandler)
{
ReleaseHandler();
Assign(aHandler, eOnBeforeUnload);
}
OnErrorEventHandlerNonNull* OnErrorEventHandler() const
{
MOZ_ASSERT(Type() == eOnError);
return reinterpret_cast<OnErrorEventHandlerNonNull*>(Ptr());
}
void SetHandler(OnErrorEventHandlerNonNull* aHandler)
{
ReleaseHandler();
Assign(aHandler, eOnError);
}
CallbackFunction* Ptr() const
{
// Have to cast eTypeBits so we don't have to worry about
// promotion issues after the bitflip.
return reinterpret_cast<CallbackFunction*>(mBits & ~uintptr_t(eTypeBits));
}
void ForgetHandler()
{
ReleaseHandler();
mBits = 0;
}
bool operator==(const nsEventHandler& aOther) const
{
return
Ptr() && aOther.Ptr() &&
Ptr()->CallbackPreserveColor() == aOther.Ptr()->CallbackPreserveColor();
}
private:
void operator=(const nsEventHandler&) 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 this interface is now used to store script objects for all
// script languages, so is no longer JS specific)
//
// Note, mTarget is a raw pointer and the owner of the nsIJSEventListener object
// is expected to call Disconnect()!
class nsIJSEventListener : public nsIDOMEventListener
{
public:
NS_DECLARE_STATIC_IID_ACCESSOR(NS_IJSEVENTLISTENER_IID)
nsIJSEventListener(nsIScriptContext* aContext, JSObject* aScopeObject,
nsISupports *aTarget, nsIAtom* aType,
const nsEventHandler& aHandler)
: mContext(aContext), mScopeObject(aScopeObject), mEventName(aType),
mHandler(aHandler)
{
nsCOMPtr<nsISupports> base = do_QueryInterface(aTarget);
mTarget = base.get();
}
// Can return null if we already have a handler.
nsIScriptContext *GetEventContext() const
{
return mContext;
}
nsISupports *GetEventTarget() const
{
return mTarget;
}
void Disconnect()
{
mTarget = nullptr;
}
// Can return null if we already have a handler.
JSObject* GetEventScope() const
{
if (!mScopeObject) {
return nullptr;
}
JS::ExposeObjectToActiveJS(mScopeObject);
return mScopeObject;
}
const nsEventHandler& GetHandler() const
{
return mHandler;
}
void ForgetHandler()
{
mHandler.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 nsEventHandler& aHandler, nsIScriptContext* aContext,
JS::Handle<JSObject*> aScopeObject)
{
mHandler.SetHandler(aHandler);
mContext = aContext;
UpdateScopeObject(aScopeObject);
}
void SetHandler(mozilla::dom::EventHandlerNonNull* aHandler)
{
mHandler.SetHandler(aHandler);
}
void SetHandler(mozilla::dom::BeforeUnloadEventHandlerNonNull* aHandler)
{
mHandler.SetHandler(aHandler);
}
void SetHandler(mozilla::dom::OnErrorEventHandlerNonNull* aHandler)
{
mHandler.SetHandler(aHandler);
}
virtual size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
{
return 0;
// Measurement of the following members may be added later if DMD finds it
// is worthwhile:
// - mContext
// - mTarget
//
// The following members are not measured:
// - mScopeObject: because they're measured by the JS memory
// reporters
// - mHandler: may be shared with others
// - mEventName: shared with others
}
virtual size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
{
return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
}
protected:
virtual ~nsIJSEventListener()
{
NS_ASSERTION(!mTarget, "Should have called Disconnect()!");
}
// Update our mScopeObject; we have to make sure we properly handle
// the hold/drop stuff, so have to do it in nsJSEventListener.
virtual void UpdateScopeObject(JS::Handle<JSObject*> aScopeObject) = 0;
nsCOMPtr<nsIScriptContext> mContext;
JS::Heap<JSObject*> mScopeObject;
nsISupports* mTarget;
nsCOMPtr<nsIAtom> mEventName;
nsEventHandler mHandler;
};
NS_DEFINE_STATIC_IID_ACCESSOR(nsIJSEventListener, NS_IJSEVENTLISTENER_IID)
/* factory function. aHandler must already be bound to aTarget.
aContext is allowed to be null if aHandler is already set up.
*/
nsresult NS_NewJSEventListener(nsIScriptContext *aContext,
JSObject* aScopeObject, nsISupports* aTarget,
nsIAtom* aType, const nsEventHandler& aHandler,
nsIJSEventListener **aReturn);
#endif // nsIJSEventListener_h__