Fixing bug 245809. Implement event.returnValue (IE:ism) for beforeunload events as the mechansim for passing data back to the browser from a beforeunload handler that was registerd with addEventListener(). r=bzbarsky@mit.edu, sr=peterv@propagandism.org

content/events/public/nsIPrivateDOMEvent.h

@@ -83,5 +83,7 @@ nsresult
 NS_NewDOMPopupBlockedEvent(nsIDOMEvent** aResult, nsPresContext* aPresContext, struct nsPopupBlockedEvent* aEvent);
 nsresult
 NS_NewDOMTextEvent(nsIDOMEvent** aResult, nsPresContext* aPresContext, struct nsTextEvent* aEvent);
+nsresult
+NS_NewDOMBeforeUnloadEvent(nsIDOMEvent** aResult, nsPresContext* aPresContext, struct nsBeforePageUnloadEvent* aEvent);
 
 #endif // nsIPrivateDOMEvent_h__

content/events/src/Makefile.in

@@ -73,6 +73,7 @@ CPPSRCS		= \
 		nsDOMMouseEvent.cpp \
 		nsDOMMutationEvent.cpp \
 		nsDOMPopupBlockedEvent.cpp \
+		nsDOMBeforeUnloadEvent.cpp \
 		nsPrivateTextRange.cpp \
 		nsDOMEventGroup.cpp \
 		nsXMLEventsManager.cpp \

content/events/src/nsDOMBeforeUnloadEvent.cpp

@@ -0,0 +1,97 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is mozilla.org code.
+ *
+ * The Initial Developer of the Original Code is
+ * The Mozilla Foundation.
+ * Portions created by the Initial Developer are Copyright (C) 2005
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *   Johnny Stenback <jst@mozilla.org> (original author)
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either the GNU General Public License Version 2 or later (the "GPL"), or
+ * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+#include "nsDOMBeforeUnloadEvent.h"
+#include "nsContentUtils.h"
+
+nsDOMBeforeUnloadEvent::nsDOMBeforeUnloadEvent(nsPresContext* aPresContext,
+                                               nsBeforePageUnloadEvent* aEvent)
+  : nsDOMEvent(aPresContext, aEvent ? aEvent : new nsBeforePageUnloadEvent(NS_BEFORE_PAGE_UNLOAD))
+{
+  NS_ASSERTION(mEvent->eventStructType == NS_BEFORE_PAGE_UNLOAD_EVENT,
+               "event type mismatch");
+
+  if (aEvent) {
+    mEventIsInternal = PR_FALSE;
+  }
+  else {
+    mEventIsInternal = PR_TRUE;
+    mEvent->time = PR_Now();
+  }
+}
+
+nsDOMBeforeUnloadEvent::~nsDOMBeforeUnloadEvent() 
+{
+}
+
+NS_IMPL_ADDREF_INHERITED(nsDOMBeforeUnloadEvent, nsDOMEvent)
+NS_IMPL_RELEASE_INHERITED(nsDOMBeforeUnloadEvent, nsDOMEvent)
+
+NS_INTERFACE_MAP_BEGIN(nsDOMBeforeUnloadEvent)
+  NS_INTERFACE_MAP_ENTRY(nsIDOMBeforeUnloadEvent)
+  NS_INTERFACE_MAP_ENTRY_CONTENT_CLASSINFO(BeforeUnloadEvent)
+NS_INTERFACE_MAP_END_INHERITING(nsDOMEvent)
+
+NS_IMETHODIMP
+nsDOMBeforeUnloadEvent::SetReturnValue(const nsAString& aReturnValue)
+{
+  ((nsBeforePageUnloadEvent *)mEvent)->text = aReturnValue;
+
+  return NS_OK;  // Don't throw an exception
+}
+
+NS_IMETHODIMP
+nsDOMBeforeUnloadEvent::GetReturnValue(nsAString& aReturnValue)
+{
+  aReturnValue = ((nsBeforePageUnloadEvent *)mEvent)->text;
+
+  return NS_OK;  // Don't throw an exception
+}
+
+nsresult NS_NewDOMBeforeUnloadEvent(nsIDOMEvent** aInstancePtrResult,
+                                    nsPresContext* aPresContext,
+                                    nsBeforePageUnloadEvent *aEvent) 
+{
+  nsDOMBeforeUnloadEvent* it =
+    new nsDOMBeforeUnloadEvent(aPresContext, aEvent);
+  if (!it) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  return CallQueryInterface(it, aInstancePtrResult);
+}

content/events/src/nsDOMBeforeUnloadEvent.h

@@ -0,0 +1,62 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is mozilla.org code.
+ *
+ * The Initial Developer of the Original Code is
+ * The Mozilla Foundation.
+ * Portions created by the Initial Developer are Copyright (C) 2005
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *   Johnny Stenback <jst@mozilla.org> (original author)
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either the GNU General Public License Version 2 or later (the "GPL"), or
+ * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+#ifndef nsDOMBeforeUnloadEvent_h__
+#define nsDOMBeforeUnloadEvent_h__
+
+#include "nsIDOMBeforeUnloadEvent.h"
+#include "nsDOMEvent.h"
+
+class nsDOMBeforeUnloadEvent : public nsIDOMBeforeUnloadEvent,
+                               public nsDOMEvent
+{
+public:
+  nsDOMBeforeUnloadEvent(nsPresContext* aPresContext,
+                         nsBeforePageUnloadEvent* aEvent);
+  virtual ~nsDOMBeforeUnloadEvent();
+
+  NS_DECL_ISUPPORTS_INHERITED
+
+  // Forward to nsDOMEvent
+  NS_FORWARD_TO_NSDOMEVENT
+
+  // nsIDOMBeforeUnloadEvent Interface
+  NS_DECL_NSIDOMBEFOREUNLOADEVENT
+};
+
+#endif // nsDOMBeforeUnloadEvent_h__

content/events/src/nsEventListenerManager.cpp

@@ -1689,6 +1689,11 @@ nsEventListenerManager::CreateEvent(nsPresContext* aPresContext,
     case NS_TEXT_EVENT:
       return NS_NewDOMTextEvent(aDOMEvent, aPresContext,
                                 NS_STATIC_CAST(nsTextEvent*,aEvent));
+    case NS_BEFORE_PAGE_UNLOAD_EVENT:
+      return
+        NS_NewDOMBeforeUnloadEvent(aDOMEvent, aPresContext,
+                                   NS_STATIC_CAST(nsBeforePageUnloadEvent*,
+                                                  aEvent));
     }
 
     // For all other types of events, create a vanilla event object.

dom/public/idl/events/Makefile.in

@@ -65,6 +65,7 @@ XPIDLSRCS =					\
 	nsIDOMMutationEvent.idl			\
 	nsIDOMNSUIEvent.idl			\
 	nsIDOMPopupBlockedEvent.idl		\
+	nsIDOMBeforeUnloadEvent.idl		\
 	$(NULL)
 
 include $(topsrcdir)/config/rules.mk

dom/public/idl/events/nsIDOMBeforeUnloadEvent.idl

@@ -0,0 +1,59 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is mozilla.org code.
+ *
+ * The Initial Developer of the Original Code is
+ * The Mozilla Foundation.
+ * Portions created by the Initial Developer are Copyright (C) 2005
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *   Johnny Stenback <jst@mozilla.org> (original author)
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either the GNU General Public License Version 2 or later (the "GPL"), or
+ * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+#include "nsIDOMEvent.idl"
+
+/**
+ * The nsIDOMBeforeUnloadEvent interface is the interface for events
+ * sent to handlers of the "beforeunload" event. This event is
+ * non-standard. Interface derived from Microsoft IE's event
+ * implementation.
+ *
+ * http://msdn.microsoft.com/library/default.asp?url=/workshop/author/dhtml/reference/events.asp
+ *
+ */
+
+[scriptable, uuid(da19e9dc-dea2-4a1d-a958-9be375c9799c)]
+interface nsIDOMBeforeUnloadEvent : nsIDOMEvent
+{
+  /**
+   * Attribute used to pass back a return value from a beforeunload
+   * handler
+   */
+           attribute DOMString          returnValue;
+};

dom/public/nsIDOMClassInfo.h

@@ -242,6 +242,8 @@ enum nsDOMClassInfoID {
 
   eDOMClassInfo_CSSMozDocumentRule_id,
 
+  eDOMClassInfo_BeforeUnloadEvent_id,
+
 #ifdef MOZ_SVG
   // The SVG document
   eDOMClassInfo_SVGDocument_id,

dom/src/base/nsDOMClassInfo.cpp

@@ -202,6 +202,7 @@
 #include "nsIDOMKeyEvent.h"
 #include "nsIDOMMouseEvent.h"
 #include "nsIDOMPopupBlockedEvent.h"
+#include "nsIDOMBeforeUnloadEvent.h"
 #include "nsIDOMMutationEvent.h"
 #include "nsIDOMNSDocumentStyle.h"
 #include "nsIDOMDocumentRange.h"
@@ -824,6 +825,9 @@ static nsDOMClassInfoData sClassInfoData[] = {
   NS_DEFINE_CLASSINFO_DATA(CSSMozDocumentRule, nsDOMGenericSH,
                            DOM_DEFAULT_SCRIPTABLE_FLAGS)
 
+  NS_DEFINE_CLASSINFO_DATA(BeforeUnloadEvent, nsDOMGenericSH,
+                           DOM_DEFAULT_SCRIPTABLE_FLAGS)
+
 #ifdef MOZ_SVG
   // SVG document
   NS_DEFINE_CLASSINFO_DATA(SVGDocument, nsDocumentSH,
@@ -2308,6 +2312,11 @@ nsDOMClassInfo::Init()
     DOM_CLASSINFO_MAP_ENTRY(nsIDOMCSSMozDocumentRule)
   DOM_CLASSINFO_MAP_END
 
+  DOM_CLASSINFO_MAP_BEGIN(BeforeUnloadEvent, nsIDOMBeforeUnloadEvent)
+    DOM_CLASSINFO_MAP_ENTRY(nsIDOMBeforeUnloadEvent)
+    DOM_CLASSINFO_EVENT_MAP_ENTRIES
+  DOM_CLASSINFO_MAP_END
+
 #ifdef MOZ_SVG
 #define DOM_CLASSINFO_SVG_ELEMENT_MAP_ENTRIES \
     DOM_CLASSINFO_MAP_ENTRY(nsIDOMSVGElement) \

dom/src/events/nsJSEventListener.cpp

@@ -194,12 +194,15 @@ nsJSEventListener::HandleEvent(nsIDOMEvent* aEvent)
       if (!JSVAL_IS_VOID(rval)) {
         aEvent->PreventDefault();
 
-        if (JSVAL_IS_STRING(rval)) {
+        // Set the text in the beforeUnload event as long as it wasn't
+        // already set (through event.returnValue, which takes
+        // precedence over a value returned from a JS function in IE)
+        if (JSVAL_IS_STRING(rval) && beforeUnload->text.IsEmpty()) {
           beforeUnload->text = nsDependentJSString(JSVAL_TO_STRING(rval));
         }
       }
     } else if (JSVAL_IS_BOOLEAN(rval)) {
-      // if the handler returned false and its sense is not reversed,
+      // If the handler returned false and its sense is not reversed,
       // or the handler returned true and its sense is reversed from
       // the usual (false means cancel), then prevent default.
 

layout/base/nsDocumentViewer.cpp

@@ -1078,7 +1078,8 @@ DocumentViewerImpl::PermitUnload(PRBool *aPermitUnload)
     mInPermitUnload = PR_FALSE;
   }
 
-  if (NS_SUCCEEDED(rv) && event.flags & NS_EVENT_FLAG_NO_DEFAULT) {
+  if (NS_SUCCEEDED(rv) && (event.flags & NS_EVENT_FLAG_NO_DEFAULT ||
+                           !event.text.IsEmpty())) {
     // Ask the user if it's ok to unload the current page
 
     nsCOMPtr<nsIPrompt> prompt(do_GetInterface(mContainer));