LCOV - code coverage report
Current view: directory - objdir/dist/include - nsEventDispatcher.h (source / functions) Found Hit Coverage
Test: app.info Lines: 22 21 95.5 %
Date: 2012-06-02 Functions: 8 7 87.5 %

       1                 : /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
       2                 : /* ***** BEGIN LICENSE BLOCK *****
       3                 :  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
       4                 :  *
       5                 :  * The contents of this file are subject to the Mozilla Public License Version
       6                 :  * 1.1 (the "License"); you may not use this file except in compliance with
       7                 :  * the License. You may obtain a copy of the License at
       8                 :  * http://www.mozilla.org/MPL/
       9                 :  *
      10                 :  * Software distributed under the License is distributed on an "AS IS" basis,
      11                 :  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
      12                 :  * for the specific language governing rights and limitations under the
      13                 :  * License.
      14                 :  *
      15                 :  * The Original Code is mozilla.org code.
      16                 :  *
      17                 :  * The Initial Developer of the Original Code is
      18                 :  * Olli Pettay (Olli.Pettay@helsinki.fi)
      19                 :  * Portions created by the Initial Developer are Copyright (C) 2006
      20                 :  * the Initial Developer. All Rights Reserved.
      21                 :  *
      22                 :  * Contributor(s):
      23                 :  *
      24                 :  * Alternatively, the contents of this file may be used under the terms of
      25                 :  * either of the GNU General Public License Version 2 or later (the "GPL"),
      26                 :  * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
      27                 :  * in which case the provisions of the GPL or the LGPL are applicable instead
      28                 :  * of those above. If you wish to allow use of your version of this file only
      29                 :  * under the terms of either the GPL or the LGPL, and not to allow others to
      30                 :  * use your version of this file under the terms of the MPL, indicate your
      31                 :  * decision by deleting the provisions above and replace them with the notice
      32                 :  * and other provisions required by the GPL or the LGPL. If you do not delete
      33                 :  * the provisions above, a recipient may use your version of this file under
      34                 :  * the terms of any one of the MPL, the GPL or the LGPL.
      35                 :  *
      36                 :  * ***** END LICENSE BLOCK ***** */
      37                 : 
      38                 : #ifdef MOZILLA_INTERNAL_API
      39                 : #ifndef nsEventDispatcher_h___
      40                 : #define nsEventDispatcher_h___
      41                 : 
      42                 : #include "nsCOMPtr.h"
      43                 : #include "nsEvent.h"
      44                 : 
      45                 : class nsIContent;
      46                 : class nsIDocument;
      47                 : class nsPresContext;
      48                 : class nsIDOMEvent;
      49                 : class nsIScriptGlobalObject;
      50                 : class nsIDOMEventTarget;
      51                 : class nsEventTargetChainItem;
      52                 : template<class E> class nsCOMArray;
      53                 : 
      54                 : /**
      55                 :  * About event dispatching:
      56                 :  * When either nsEventDispatcher::Dispatch or
      57                 :  * nsEventDispatcher::DispatchDOMEvent is called an event target chain is
      58                 :  * created. nsEventDispatcher creates the chain by calling PreHandleEvent 
      59                 :  * on each event target and the creation continues until either the mCanHandle
      60                 :  * member of the nsEventChainPreVisitor object is false or the mParentTarget
      61                 :  * does not point to a new target. The event target chain is created in the
      62                 :  * heap.
      63                 :  *
      64                 :  * If the event needs retargeting, mEventTargetAtParent must be set in
      65                 :  * PreHandleEvent.
      66                 :  *
      67                 :  * The capture, target and bubble phases of the event dispatch are handled
      68                 :  * by iterating through the event target chain. Iteration happens twice,
      69                 :  * first for the default event group and then for the system event group.
      70                 :  * While dispatching the event for the system event group PostHandleEvent
      71                 :  * is called right after calling event listener for the current event target.
      72                 :  */
      73                 : 
      74           32762 : class nsEventChainVisitor {
      75                 : public:
      76           32762 :   nsEventChainVisitor(nsPresContext* aPresContext,
      77                 :                       nsEvent* aEvent,
      78                 :                       nsIDOMEvent* aDOMEvent,
      79                 :                       nsEventStatus aEventStatus = nsEventStatus_eIgnore)
      80                 :   : mPresContext(aPresContext), mEvent(aEvent), mDOMEvent(aDOMEvent),
      81           32762 :     mEventStatus(aEventStatus), mItemFlags(0)
      82           32762 :   {}
      83                 : 
      84                 :   /**
      85                 :    * The prescontext, possibly nsnull.
      86                 :    */
      87                 :   nsPresContext* const  mPresContext;
      88                 : 
      89                 :   /**
      90                 :    * The nsEvent which is being dispatched. Never nsnull.
      91                 :    */
      92                 :   nsEvent* const        mEvent;
      93                 : 
      94                 :   /**
      95                 :    * The DOM Event assiciated with the mEvent. Possibly nsnull if a DOM Event
      96                 :    * is not (yet) created.
      97                 :    */
      98                 :   nsIDOMEvent*          mDOMEvent;
      99                 : 
     100                 :   /**
     101                 :    * The status of the event.
     102                 :    * @see nsEventStatus.h
     103                 :    */
     104                 :   nsEventStatus         mEventStatus;
     105                 : 
     106                 :   /**
     107                 :    * Bits for items in the event target chain.
     108                 :    * Set in PreHandleEvent() and used in PostHandleEvent().
     109                 :    *
     110                 :    * @note These bits are different for each item in the event target chain.
     111                 :    *       It is up to the Pre/PostHandleEvent implementation to decide how to
     112                 :    *       use these bits.
     113                 :    *
     114                 :    * @note Using PRUint16 because that is used also in nsEventTargetChainItem.
     115                 :    */
     116                 :   PRUint16              mItemFlags;
     117                 : 
     118                 :   /**
     119                 :    * Data for items in the event target chain.
     120                 :    * Set in PreHandleEvent() and used in PostHandleEvent().
     121                 :    *
     122                 :    * @note This data is different for each item in the event target chain.
     123                 :    *       It is up to the Pre/PostHandleEvent implementation to decide how to
     124                 :    *       use this.
     125                 :    */
     126                 :   nsCOMPtr<nsISupports> mItemData;
     127                 : };
     128                 : 
     129           16381 : class nsEventChainPreVisitor : public nsEventChainVisitor {
     130                 : public:
     131           16381 :   nsEventChainPreVisitor(nsPresContext* aPresContext,
     132                 :                          nsEvent* aEvent,
     133                 :                          nsIDOMEvent* aDOMEvent,
     134                 :                          nsEventStatus aEventStatus,
     135                 :                          bool aIsInAnon)
     136                 :   : nsEventChainVisitor(aPresContext, aEvent, aDOMEvent, aEventStatus),
     137                 :     mCanHandle(true), mForceContentDispatch(false),
     138                 :     mRelatedTargetIsInAnon(false), mOriginalTargetIsInAnon(aIsInAnon),
     139                 :     mWantsWillHandleEvent(false), mMayHaveListenerManager(true),
     140           16381 :     mParentTarget(nsnull), mEventTargetAtParent(nsnull) {}
     141                 : 
     142           25419 :   void Reset() {
     143           25419 :     mItemFlags = 0;
     144           25419 :     mItemData = nsnull;
     145           25419 :     mCanHandle = true;
     146           25419 :     mForceContentDispatch = false;
     147           25419 :     mWantsWillHandleEvent = false;
     148           25419 :     mMayHaveListenerManager = true;
     149           25419 :     mParentTarget = nsnull;
     150           25419 :     mEventTargetAtParent = nsnull;
     151           25419 :   }
     152                 : 
     153                 :   /**
     154                 :    * Member that must be set in PreHandleEvent by event targets. If set to false,
     155                 :    * indicates that this event target will not be handling the event and
     156                 :    * construction of the event target chain is complete. The target that sets
     157                 :    * mCanHandle to false is NOT included in the event target chain.
     158                 :    */
     159                 :   bool                  mCanHandle;
     160                 : 
     161                 :   /**
     162                 :    * If mForceContentDispatch is set to true,
     163                 :    * content dispatching is not disabled for this event target.
     164                 :    * FIXME! This is here for backward compatibility. Bug 329119
     165                 :    */
     166                 :   bool                  mForceContentDispatch;
     167                 : 
     168                 :   /**
     169                 :    * true if it is known that related target is or is a descendant of an
     170                 :    * element which is anonymous for events.
     171                 :    */
     172                 :   bool                  mRelatedTargetIsInAnon;
     173                 : 
     174                 :   /**
     175                 :    * true if the original target of the event is inside anonymous content.
     176                 :    * This is set before calling PreHandleEvent on event targets.
     177                 :    */
     178                 :   bool                  mOriginalTargetIsInAnon;
     179                 : 
     180                 :   /**
     181                 :    * Whether or not nsIDOMEventTarget::WillHandleEvent will be
     182                 :    * called. Default is false;
     183                 :    */
     184                 :   bool                  mWantsWillHandleEvent;
     185                 : 
     186                 :   /**
     187                 :    * If it is known that the current target doesn't have a listener manager
     188                 :    * when PreHandleEvent is called, set this to false.
     189                 :    */
     190                 :   bool                  mMayHaveListenerManager;
     191                 : 
     192                 :   /**
     193                 :    * Parent item in the event target chain.
     194                 :    */
     195                 :   nsIDOMEventTarget*   mParentTarget;
     196                 : 
     197                 :   /**
     198                 :    * If the event needs to be retargeted, this is the event target,
     199                 :    * which should be used when the event is handled at mParentTarget.
     200                 :    */
     201                 :   nsIDOMEventTarget*   mEventTargetAtParent;
     202                 : };
     203                 : 
     204           16381 : class nsEventChainPostVisitor : public nsEventChainVisitor {
     205                 : public:
     206           16381 :   nsEventChainPostVisitor(nsEventChainVisitor& aOther)
     207                 :   : nsEventChainVisitor(aOther.mPresContext, aOther.mEvent, aOther.mDOMEvent,
     208           16381 :                         aOther.mEventStatus)
     209           16381 :   {}
     210                 : };
     211                 : 
     212                 : /**
     213                 :  * If an nsDispatchingCallback object is passed to Dispatch,
     214                 :  * its HandleEvent method is called after handling the default event group,
     215                 :  * before handling the system event group.
     216                 :  * This is used in nsPresShell.
     217                 :  */
     218               0 : class NS_STACK_CLASS nsDispatchingCallback {
     219                 : public:
     220                 :   virtual void HandleEvent(nsEventChainPostVisitor& aVisitor) = 0;
     221                 : };
     222                 : 
     223                 : /**
     224                 :  * The generic class for event dispatching.
     225                 :  * Must not be used outside Gecko!
     226                 :  */
     227                 : class nsEventDispatcher
     228                 : {
     229                 : public:
     230                 :   /**
     231                 :    * aTarget should QI to nsIDOMEventTarget.
     232                 :    * If the target of aEvent is set before calling this method, the target of 
     233                 :    * aEvent is used as the target (unless there is event
     234                 :    * retargeting) and the originalTarget of the DOM Event.
     235                 :    * aTarget is always used as the starting point for constructing the event
     236                 :    * target chain, no matter what the value of aEvent->target is.
     237                 :    * In other words, aEvent->target is only a property of the event and it has
     238                 :    * nothing to do with the construction of the event target chain.
     239                 :    * Neither aTarget nor aEvent is allowed to be nsnull.
     240                 :    *
     241                 :    * If aTargets is non-null, event target chain will be created, but
     242                 :    * event won't be handled. In this case aEvent->message should be
     243                 :    * NS_EVENT_TYPE_NULL.
     244                 :    * @note Use this method when dispatching an nsEvent.
     245                 :    */
     246                 :   static nsresult Dispatch(nsISupports* aTarget,
     247                 :                            nsPresContext* aPresContext,
     248                 :                            nsEvent* aEvent,
     249                 :                            nsIDOMEvent* aDOMEvent = nsnull,
     250                 :                            nsEventStatus* aEventStatus = nsnull,
     251                 :                            nsDispatchingCallback* aCallback = nsnull,
     252                 :                            nsCOMArray<nsIDOMEventTarget>* aTargets = nsnull);
     253                 : 
     254                 :   /**
     255                 :    * Dispatches an event.
     256                 :    * If aDOMEvent is not nsnull, it is used for dispatching
     257                 :    * (aEvent can then be nsnull) and (if aDOMEvent is not |trusted| already),
     258                 :    * the |trusted| flag is set based on the UniversalXPConnect capability.
     259                 :    * Otherwise this works like nsEventDispatcher::Dispatch.
     260                 :    * @note Use this method when dispatching nsIDOMEvent.
     261                 :    */
     262                 :   static nsresult DispatchDOMEvent(nsISupports* aTarget,
     263                 :                                    nsEvent* aEvent, nsIDOMEvent* aDOMEvent,
     264                 :                                    nsPresContext* aPresContext,
     265                 :                                    nsEventStatus* aEventStatus);
     266                 : 
     267                 :   /**
     268                 :    * Creates a DOM Event.
     269                 :    */
     270                 :   static nsresult CreateEvent(nsPresContext* aPresContext,
     271                 :                               nsEvent* aEvent,
     272                 :                               const nsAString& aEventType,
     273                 :                               nsIDOMEvent** aDOMEvent);
     274                 : 
     275                 : };
     276                 : 
     277                 : #endif
     278                 : #endif

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