content/events/src/nsDOMDragEvent.cpp

   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 the Mozilla Corporation.
  18  * Portions created by the Initial Developer are Copyright (C) 2008
  19  * the Initial Developer. All Rights Reserved.
  20  *
  21  * Contributor(s):
  22  *   Neil Deakin <enndeakin@gmail.com>
  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 #include "nsDOMDragEvent.h"
  39 #include "nsIServiceManager.h"
  40 #include "nsGUIEvent.h"
  41 #include "nsContentUtils.h"
  42 #include "nsIEventStateManager.h"
  43 #include "nsDOMDataTransfer.h"
  44 #include "nsIDragService.h"
  45
  46 nsDOMDragEvent::nsDOMDragEvent(nsPresContext* aPresContext,
  47                                nsInputEvent* aEvent)
  48   : nsDOMMouseEvent(aPresContext, aEvent ? aEvent :
  49                     new nsDragEvent(PR_FALSE, 0, nsnull))
  50 {
  51   if (aEvent) {
  52     mEventIsInternal = PR_FALSE;
  53   }
  54   else {
  55     mEventIsInternal = PR_TRUE;
  56     mEvent->time = PR_Now();
  57     mEvent->refPoint.x = mEvent->refPoint.y = 0;
  58   }
  59 }
  60
  61 nsDOMDragEvent::~nsDOMDragEvent()
  62 {
  63   if (mEventIsInternal) {
  64     if (mEvent->eventStructType == NS_DRAG_EVENT)
  65       delete static_cast<nsDragEvent*>(mEvent);
  66     mEvent = nsnull;
  67   }
  68 }
  69
  70 NS_IMPL_ADDREF_INHERITED(nsDOMDragEvent, nsDOMMouseEvent)
  71 NS_IMPL_RELEASE_INHERITED(nsDOMDragEvent, nsDOMMouseEvent)
  72
  73 NS_INTERFACE_MAP_BEGIN(nsDOMDragEvent)
  74   NS_INTERFACE_MAP_ENTRY(nsIDOMDragEvent)
  75   NS_INTERFACE_MAP_ENTRY_CONTENT_CLASSINFO(DragEvent)
  76 NS_INTERFACE_MAP_END_INHERITING(nsDOMMouseEvent)
  77
  78 NS_IMETHODIMP
  79 nsDOMDragEvent::InitDragEvent(const nsAString & aType,
  80                               PRBool aCanBubble, PRBool aCancelable,
  81                               nsIDOMAbstractView* aView, PRInt32 aDetail,
  82                               PRInt32 aScreenX, PRInt32 aScreenY,
  83                               PRInt32 aClientX, PRInt32 aClientY,
  84                               PRBool aCtrlKey, PRBool aAltKey, PRBool aShiftKey,
  85                               PRBool aMetaKey, PRUint16 aButton,
  86                               nsIDOMEventTarget *aRelatedTarget,
  87                               nsIDOMDataTransfer* aDataTransfer)
  88 {
  89   nsresult rv = nsDOMMouseEvent::InitMouseEvent(aType, aCanBubble, aCancelable,
  90                   aView, aDetail, aScreenX, aScreenY, aClientX, aClientY,
  91                   aCtrlKey, aAltKey, aShiftKey, aMetaKey, aButton,
  92                   aRelatedTarget);
  93   NS_ENSURE_SUCCESS(rv, rv);
  94
  95   if (mEventIsInternal && mEvent) {
  96     nsDragEvent* dragEvent = static_cast<nsDragEvent*>(mEvent);
  97     dragEvent->dataTransfer = aDataTransfer;
  98   }
  99
 100   return NS_OK;
 101 }
 102
 103 NS_IMETHODIMP
 104 nsDOMDragEvent::InitDragEventNS(const nsAString & aNamespaceURIArg,
 105                                 const nsAString & aType,
 106                                 PRBool aCanBubble, PRBool aCancelable,
 107                                 nsIDOMAbstractView* aView, PRInt32 aDetail,
 108                                 PRInt32 aScreenX, PRInt32 aScreenY,
 109                                 PRInt32 aClientX, PRInt32 aClientY,
 110                                 PRBool aCtrlKey, PRBool aAltKey, PRBool aShiftKey,
 111                                 PRBool aMetaKey, PRUint16 aButton,
 112                                 nsIDOMEventTarget *aRelatedTarget,
 113                                 nsIDOMDataTransfer* aDataTransfer)
 114 {
 115   return NS_ERROR_NOT_IMPLEMENTED;
 116 }
 117
 118 NS_IMETHODIMP
 119 nsDOMDragEvent::GetDataTransfer(nsIDOMDataTransfer** aDataTransfer)
 120 {
 121   *aDataTransfer = nsnull;
 122
 123   if (!mEvent || mEvent->eventStructType != NS_DRAG_EVENT) {
 124     NS_WARNING("Tried to get dataTransfer from non-drag event!");
 125     return NS_OK;
 126   }
 127
 128   // the dataTransfer field of the event caches the DataTransfer associated
 129   // with the drag. It is initialized when an attempt is made to retrieve it
 130   // rather that when the event is created to avoid duplicating the data when
 131   // no listener ever uses it.
 132   nsDragEvent* dragEvent = static_cast<nsDragEvent*>(mEvent);
 133   if (dragEvent->dataTransfer) {
 134     CallQueryInterface(dragEvent->dataTransfer, aDataTransfer);
 135     return NS_OK;
 136   }
 137
 138   // for synthetic events, just use the supplied data transfer object
 139   if (mEventIsInternal) {
 140     NS_IF_ADDREF(*aDataTransfer = dragEvent->dataTransfer);
 141     return NS_OK;
 142   }
 143
 144   // For draggesture and dragstart events, the data transfer object is
 145   // created before the event fires, so it should already be set. For other
 146   // drag events, get the object from the drag session.
 147   NS_ASSERTION(mEvent->message != NS_DRAGDROP_GESTURE &&
 148                mEvent->message != NS_DRAGDROP_START,
 149                "draggesture event created without a dataTransfer");
 150
 151   nsCOMPtr<nsIDragSession> dragSession = nsContentUtils::GetDragSession();
 152   NS_ENSURE_TRUE(dragSession, NS_OK); // no drag in progress
 153
 154   nsCOMPtr<nsIDOMDataTransfer> initialDataTransfer;
 155   dragSession->GetDataTransfer(getter_AddRefs(initialDataTransfer));
 156   if (!initialDataTransfer) {
 157     // A dataTransfer won't exist when a drag was started by some other
 158     // means, for instance calling the drag service directly, or a drag
 159     // from another application. In either case, a new dataTransfer should
 160     // be created that reflects the data. Pass true to the constructor for
 161     // the aIsExternal argument, so that only system access is allowed.
 162     PRUint32 action = 0;
 163     dragSession->GetDragAction(&action);
 164     initialDataTransfer =
 165       new nsDOMDataTransfer(mEvent->message, action);
 166     NS_ENSURE_TRUE(initialDataTransfer, NS_ERROR_OUT_OF_MEMORY);
 167
 168     // now set it in the drag session so we don't need to create it again
 169     dragSession->SetDataTransfer(initialDataTransfer);
 170   }
 171
 172   // each event should use a clone of the original dataTransfer.
 173   nsCOMPtr<nsIDOMNSDataTransfer> initialDataTransferNS =
 174     do_QueryInterface(initialDataTransfer);
 175   NS_ENSURE_TRUE(initialDataTransferNS, NS_ERROR_FAILURE);
 176   initialDataTransferNS->Clone(mEvent->message,
 177                                getter_AddRefs(dragEvent->dataTransfer));
 178   NS_ENSURE_TRUE(dragEvent->dataTransfer, NS_ERROR_OUT_OF_MEMORY);
 179
 180   // for the dragenter and dragover events, initialize the drop effect
 181   // from the drop action, which platform specific widget code sets before
 182   // the event is fired based on the keyboard state.
 183   if (mEvent->message == NS_DRAGDROP_ENTER ||
 184       mEvent->message == NS_DRAGDROP_OVER) {
 185     nsCOMPtr<nsIDOMNSDataTransfer> newDataTransfer =
 186       do_QueryInterface(dragEvent->dataTransfer);
 187     NS_ENSURE_TRUE(newDataTransfer, NS_ERROR_FAILURE);
 188
 189     PRUint32 action, effectAllowed;
 190     dragSession->GetDragAction(&action);
 191     newDataTransfer->GetEffectAllowedInt(&effectAllowed);
 192     newDataTransfer->SetDropEffectInt(FilterDropEffect(action, effectAllowed));
 193   }
 194   else if (mEvent->message == NS_DRAGDROP_DROP ||
 195            mEvent->message == NS_DRAGDROP_DRAGDROP ||
 196            mEvent->message == NS_DRAGDROP_END) {
 197     // For the drop and dragend events, set the drop effect based on the
 198     // last value that the dropEffect had. This will have been set in
 199     // nsEventStateManager::PostHandleEvent for the last dragenter or
 200     // dragover event.
 201     nsCOMPtr<nsIDOMNSDataTransfer> newDataTransfer =
 202       do_QueryInterface(dragEvent->dataTransfer);
 203     NS_ENSURE_TRUE(newDataTransfer, NS_ERROR_FAILURE);
 204
 205     PRUint32 dropEffect;
 206     initialDataTransferNS->GetDropEffectInt(&dropEffect);
 207     newDataTransfer->SetDropEffectInt(dropEffect);
 208   }
 209
 210   NS_IF_ADDREF(*aDataTransfer = dragEvent->dataTransfer);
 211   return NS_OK;
 212 }
 213
 214 // static
 215 PRUint32
 216 nsDOMDragEvent::FilterDropEffect(PRUint32 aAction, PRUint32 aEffectAllowed)
 217 {
 218   // It is possible for the drag action to include more than one action, but
 219   // the widget code which sets the action from the keyboard state should only
 220   // be including one. If multiple actions were set, we just consider them in
 221   //  the following order:
 222   //   copy, link, move
 223   if (aAction & nsIDragService::DRAGDROP_ACTION_COPY)
 224     aAction = nsIDragService::DRAGDROP_ACTION_COPY;
 225   else if (aAction & nsIDragService::DRAGDROP_ACTION_LINK)
 226     aAction = nsIDragService::DRAGDROP_ACTION_LINK;
 227   else if (aAction & nsIDragService::DRAGDROP_ACTION_MOVE)
 228     aAction = nsIDragService::DRAGDROP_ACTION_MOVE;
 229
 230   // Filter the action based on the effectAllowed. If the effectAllowed
 231   // doesn't include the action, then that action cannot be done, so adjust
 232   // the action to something that is allowed. For a copy, adjust to move or
 233   // link. For a move, adjust to copy or link. For a link, adjust to move or
 234   // link. Otherwise, use none.
 235   if (aAction & aEffectAllowed ||
 236       aEffectAllowed == nsIDragService::DRAGDROP_ACTION_UNINITIALIZED)
 237     return aAction;
 238   if (aEffectAllowed & nsIDragService::DRAGDROP_ACTION_MOVE)
 239     return nsIDragService::DRAGDROP_ACTION_MOVE;
 240   if (aEffectAllowed & nsIDragService::DRAGDROP_ACTION_COPY)
 241     return nsIDragService::DRAGDROP_ACTION_COPY;
 242   if (aEffectAllowed & nsIDragService::DRAGDROP_ACTION_LINK)
 243     return nsIDragService::DRAGDROP_ACTION_LINK;
 244   return nsIDragService::DRAGDROP_ACTION_NONE;
 245 }
 246
 247 nsresult NS_NewDOMDragEvent(nsIDOMEvent** aInstancePtrResult,
 248                             nsPresContext* aPresContext,
 249                             nsDragEvent *aEvent)
 250 {
 251   nsDOMDragEvent* event = new nsDOMDragEvent(aPresContext, aEvent);
 252   NS_ENSURE_TRUE(event, NS_ERROR_OUT_OF_MEMORY);
 253
 254   return CallQueryInterface(event, aInstancePtrResult);
 255 }