<?xml version="1.0"?>

<!-- ***** 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 this file as it was released on March 28, 2001.
   -
   - The Initial Developer of the Original Code is
   - Peter Annema.
   - Portions created by the Initial Developer are Copyright (C) 2001
   - the Initial Developer. All Rights Reserved.
   -
   - Contributor(s):
   -   Peter Annema <disttsc@bart.nl> (Original Author of <browser>)
   -   Peter Parente <parente@cs.unc.edu>
   -   Christopher Thomas <cst@yecc.com>
   -   Michael Ventnor <m.ventnor@gmail.com>
   -   Arpad Borsos <arpad.borsos@googlemail.com>
   -
   - 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 ***** -->

<!DOCTYPE bindings [
  <!ENTITY % findBarDTD SYSTEM "chrome://global/locale/findbar.dtd" >
  %findBarDTD;
]>

<bindings id="browserBindings"
          xmlns="http://www.mozilla.org/xbl"
          xmlns:xul="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">

  <binding id="browser" extends="xul:browser">
    <content clickthrough="never">
      <children/>
    </content>
    <implementation type="application/javascript" implements="nsIAccessibleProvider, nsIObserver, nsIDOMEventListener">
      <property name="accessibleType" readonly="true">
        <getter>
          <![CDATA[
            return Components.interfaces.nsIAccessibleProvider.OuterDoc;
          ]]>
        </getter>
      </property>

      <property name="autoscrollEnabled">
        <getter>
          <![CDATA[
            if (this.getAttribute("autoscroll") == "false")
              return false;
            
            var enabled = true;
            try {
              enabled = this.mPrefs.getBoolPref("general.autoScroll");
            }
            catch(ex) {
            }
            
            return enabled;
          ]]>
        </getter>
      </property>

      <property name="canGoBack"
                onget="return this.webNavigation.canGoBack;"
                readonly="true"/>

      <property name="canGoForward"
                onget="return this.webNavigation.canGoForward;"
                readonly="true"/>

      <method name="goBack">
        <body>
          <![CDATA[
            var webNavigation = this.webNavigation;
            if (webNavigation.canGoBack) {
              try {
                this.userTypedClear++;
                webNavigation.goBack();
              } finally {
                if (this.userTypedClear)
                  this.userTypedClear--;
              }
            }
          ]]>
        </body>
      </method>

      <method name="goForward">
        <body>
          <![CDATA[
            var webNavigation = this.webNavigation;
            if (webNavigation.canGoForward) {
              try {
                this.userTypedClear++;
                webNavigation.goForward();
              } finally {
                if (this.userTypedClear)
                  this.userTypedClear--;
              }
            }
          ]]>
        </body>
      </method>

      <method name="reload">
        <body>
          <![CDATA[
            const nsIWebNavigation = Components.interfaces.nsIWebNavigation;
            const flags = nsIWebNavigation.LOAD_FLAGS_NONE;
            this.reloadWithFlags(flags);
          ]]>
        </body>
      </method>

      <method name="reloadWithFlags">
        <parameter name="aFlags"/>
        <body>
          <![CDATA[
            this.webNavigation.reload(aFlags);
          ]]>
        </body>
      </method>

      <method name="stop">
        <body>
          <![CDATA[
            const nsIWebNavigation = Components.interfaces.nsIWebNavigation;
            const flags = nsIWebNavigation.STOP_ALL;
            this.webNavigation.stop(flags);
          ]]>
        </body>
      </method>

      <!-- throws exception for unknown schemes -->
      <method name="loadURI">
        <parameter name="aURI"/>
        <parameter name="aReferrerURI"/>
        <parameter name="aCharset"/>
        <body>
          <![CDATA[
            const nsIWebNavigation = Components.interfaces.nsIWebNavigation;
            const flags = nsIWebNavigation.LOAD_FLAGS_NONE;
            this.loadURIWithFlags(aURI, flags, aReferrerURI, aCharset);
          ]]>
        </body>
      </method>

      <!-- throws exception for unknown schemes -->
      <method name="loadURIWithFlags">
        <parameter name="aURI"/>
        <parameter name="aFlags"/>
        <parameter name="aReferrerURI"/>
        <parameter name="aCharset"/>
        <parameter name="aPostData"/>
        <body>
          <![CDATA[
            if (!aURI)
              aURI = "about:blank";

            if (aCharset) {
              try { 
                this.documentCharsetInfo.parentCharset = this.mAtomService.getAtom(aCharset);
              }
              catch (e) {
              }
            }

            if (!(aFlags & this.webNavigation.LOAD_FLAGS_FROM_EXTERNAL))
              this.userTypedClear++;

            try {
              this.webNavigation.loadURI(aURI, aFlags, aReferrerURI, aPostData, null);
            } finally {
              if (this.userTypedClear)
                this.userTypedClear--;
            }
          ]]>
        </body>
      </method>

      <method name="goHome">
        <body>
          <![CDATA[
            try {
              this.loadURI(this.homePage);
            }
            catch (e) {
            }
          ]]>
        </body>
      </method>

      <property name="homePage">
        <getter>
          <![CDATA[
            var uri;

            if (this.hasAttribute("homepage"))
              uri = this.getAttribute("homepage");
            else
              uri = "http://www.mozilla.org/"; // widget pride

            return uri;
          ]]>
        </getter>
        <setter>
          <![CDATA[
            this.setAttribute("homepage", val);
            return val;
          ]]>
        </setter>
      </property>

      <method name="gotoIndex">
        <parameter name="aIndex"/>
        <body>
          <![CDATA[
            try {
              this.userTypedClear++;
              this.webNavigation.gotoIndex(aIndex);
            } finally {
              if (this.userTypedClear)
                this.userTypedClear--;
            }
          ]]>
        </body>
      </method>

      <property name="currentURI"
                onget="return this.webNavigation.currentURI;"
                readonly="true"/>

      <property name="preferences"
                onget="return Components.classes['@mozilla.org/preferences-service;1'].getService(Components.interfaces.nsIPrefService);"
                readonly="true"/>

      <field name="_docShell">null</field>

      <property name="docShell"
                onget="return this._docShell || (this._docShell = this.boxObject.QueryInterface(Components.interfaces.nsIContainerBoxObject).docShell);"
                readonly="true"/>

      <property name="docShellIsActive">
        <getter>
          <![CDATA[
            return this.docShell && this.docShell.isActive;
          ]]>
        </getter>
        <setter>
          <![CDATA[
            if (this.docShell)
              return this.docShell.isActive = val;
            return false;
          ]]>
        </setter>
      </property>

      <property name="isRemoteBrowser"
                onget="return (this.getAttribute('remote') == 'true');"
                readonly="true"/>

      <property name="messageManager"
                onget="return this.QueryInterface(Components.interfaces.nsIFrameLoaderOwner).frameLoader.messageManager;"
                readonly="true"/>

      <field name="_webNavigation">null</field>

      <field name="_remoteWebNavigation"><![CDATA[
        ({
          LOAD_FLAGS_MASK: 65535,
          LOAD_FLAGS_NONE: 0,
          LOAD_FLAGS_IS_REFRESH: 16,
          LOAD_FLAGS_IS_LINK: 32,
          LOAD_FLAGS_BYPASS_HISTORY: 64,
          LOAD_FLAGS_REPLACE_HISTORY: 128,
          LOAD_FLAGS_BYPASS_CACHE: 256,
          LOAD_FLAGS_BYPASS_PROXY: 512,
          LOAD_FLAGS_CHARSET_CHANGE: 1024,
          LOAD_FLAGS_STOP_CONTENT: 2048,
          LOAD_FLAGS_FROM_EXTERNAL: 4096,
          LOAD_FLAGS_ALLOW_THIRD_PARTY_FIXUP: 8192,
          LOAD_FLAGS_FIRST_LOAD: 16384,
          LOAD_FLAGS_ALLOW_POPUPS: 32768,
          LOAD_FLAGS_BYPASS_CLASSIFIER: 65536,
          LOAD_FLAGS_FORCE_ALLOW_COOKIES: 131072,

          STOP_NETWORK: 1,
          STOP_CONTENT: 2,
          STOP_ALL: 3,

          canGoBack: false,
          canGoForward: false,
          goBack: function() { this._sendMessage("WebNavigation:GoBack", {}); },
          goForward: function() { this._sendMessage("WebNavigation:GoForward", {}); },
          gotoIndex: function(aIndex) { this._sendMessage("WebNavigation:GotoIndex", {index: aIndex}); },
          loadURI: function(aURI, aLoadFlags, aReferrer, aPostData, aHeaders) {
            this._browser.userTypedValue = aURI;
            this._browser._contentTitle = "";
            this._sendMessage("WebNavigation:LoadURI", {uri: aURI, flags: aLoadFlags});
          },
          reload: function(aReloadFlags) { this._sendMessage("WebNavigation:Reload", {flags: aReloadFlags}); },
          stop: function(aStopFlags) { this._sendMessage("WebNavigation:Stop", {flags: aStopFlags}); },
          get document() { Components.utils.reportError("contentDocument is not available"); return null; },
          get currentURI() {
            if (!this._currentURI)
               this._currentURI = Components.classes["@mozilla.org/network/io-service;1"].getService(Components.interfaces.nsIIOService).newURI("about:blank", null, null);

            return this._currentURI;
          },
          set currentURI(aURI) { this.loadURI(aURI.spec, null, null, null); },
          referringURI: null,
          get sessionHistory() { return null; },
          set sessionHistory(aValue) { },

          _currentURI: null,
          _browser: this,
          _sendMessage: function(aMessage, aData) {
            try {
              this._browser.messageManager.sendAsyncMessage(aMessage, aData);
            }
            catch (e) {
              Components.utils.reportError(e);
            }
         },

         QueryInterface: function(aIID) {
           if (aIID.equals(Components.interfaces.nsIWebNavigation) || aIID.equals(Components.interfaces.nsISupports))
             return this;
           throw Components.results.NS_NOINTERFACE;
         }
        })
      ]]></field>

      <property name="webNavigation"
                readonly="true">
        <getter>
        <![CDATA[
          if (!this._webNavigation)
            this._webNavigation = this.isRemoteBrowser ? this._remoteWebNavigation : this.docShell.QueryInterface(Components.interfaces.nsIWebNavigation);
          return this._webNavigation;
        ]]>
        </getter>
      </property>

      <field name="_webBrowserFind">null</field>

      <property name="webBrowserFind"
                readonly="true">
        <getter>
        <![CDATA[
          if (!this._webBrowserFind)
            this._webBrowserFind = this.docShell.QueryInterface(Components.interfaces.nsIInterfaceRequestor).getInterface(Components.interfaces.nsIWebBrowserFind);
          return this._webBrowserFind;
        ]]>
        </getter>
      </property>

      <method name="getTabBrowser">
        <body>
          <![CDATA[
            var tabBrowser = this.parentNode;
            while (tabBrowser && tabBrowser.localName != "tabbrowser")
              tabBrowser = tabBrowser.parentNode;
            return tabBrowser;
          ]]>
        </body>
      </method>

      <field name="_fastFind">null</field>
      <property name="fastFind"
                readonly="true">
        <getter>
        <![CDATA[
          if (!this._fastFind) {
            if (!("@mozilla.org/typeaheadfind;1" in Components.classes))
              return null;

            var tabBrowser = this.getTabBrowser();
            if (tabBrowser)
              return this._fastFind = tabBrowser.fastFind;

            if (!this.docShell)
              return null;

            this._fastFind = Components.classes["@mozilla.org/typeaheadfind;1"]
                                       .createInstance(Components.interfaces.nsITypeAheadFind);                                
            this._fastFind.init(this.docShell);
          }
          return this._fastFind;
        ]]>
        </getter>
      </property>
      
      <property name="webProgress"
                readonly="true"
                onget="return this.docShell.QueryInterface(Components.interfaces.nsIInterfaceRequestor).getInterface(Components.interfaces.nsIWebProgress);"/>

      <field name="_contentWindow">null</field>

      <property name="contentWindow"
                readonly="true"
                onget="return this._contentWindow || (this._contentWindow = this.docShell.QueryInterface(Components.interfaces.nsIInterfaceRequestor).getInterface(Components.interfaces.nsIDOMWindow));"/>

      <property name="sessionHistory"
                onget="return this.webNavigation.sessionHistory;"
                readonly="true"/>

      <property name="markupDocumentViewer"
                onget="return this.docShell.contentViewer.QueryInterface(Components.interfaces.nsIMarkupDocumentViewer);"
                readonly="true"/>

      <property name="contentViewerEdit"
                onget="return this.docShell.contentViewer.QueryInterface(Components.interfaces.nsIContentViewerEdit);"
                readonly="true"/>

      <property name="contentViewerFile"
                onget="return this.docShell.contentViewer.QueryInterface(Components.interfaces.nsIContentViewerFile);"
                readonly="true"/>

      <property name="documentCharsetInfo"
                onget="return this.docShell.documentCharsetInfo;"
                readonly="true"/>

      <property name="contentDocument"
                onget="return this.webNavigation.document;"
                readonly="true"/>

      <property name="contentTitle"
                onget="return this.contentDocument.title;"
                readonly="true"/>

      <property name="contentPrincipal"
                onget="return this.contentDocument.nodePrincipal;"
                readonly="true"/>

      <property name="showWindowResizer"
                onset="if (val) this.setAttribute('showresizer', 'true');
                       else this.removeAttribute('showresizer');
                       return val;"
                onget="return this.getAttribute('showresizer') == 'true';"/>

      <field name="mPrefs" readonly="true">
        Components.classes['@mozilla.org/preferences-service;1']
                  .getService(Components.interfaces.nsIPrefService)
                  .getBranch(null);
      </field>

      <field name="mAtomService" readonly="true">
        Components.classes['@mozilla.org/atom-service;1']
                  .getService(Components.interfaces.nsIAtomService);
      </field>

      <field name="_mStrBundle">null</field>

      <property name="mStrBundle">
        <getter>
        <![CDATA[
          if (!this._mStrBundle) {
            // need to create string bundle manually instead of using <xul:stringbundle/>
            // see bug 63370 for details
            this._mStrBundle = Components.classes["@mozilla.org/intl/stringbundle;1"]
                                         .getService(Components.interfaces.nsIStringBundleService)
                                         .createBundle("chrome://global/locale/browser.properties");
          }
          return this._mStrBundle;
        ]]></getter>
      </property>

      <method name="addProgressListener">
        <parameter name="aListener"/>
        <body>
          <![CDATA[
            this.webProgress.addProgressListener(aListener, Components.interfaces.nsIWebProgress.NOTIFY_ALL);
          ]]>
        </body>
      </method>

      <method name="removeProgressListener">
        <parameter name="aListener"/>
        <body>
          <![CDATA[
            this.webProgress.removeProgressListener(aListener);
         ]]>
        </body>
      </method>

      <method name="attachFormFill">
        <body>
          <![CDATA[
          if (!this.mFormFillAttached && this.hasAttribute("autocompletepopup")) {
            // hoop up the form fill autocomplete controller
            var controller = Components.classes["@mozilla.org/satchel/form-fill-controller;1"].
                               getService(Components.interfaces.nsIFormFillController);

            var popup = document.getElementById(this.getAttribute("autocompletepopup"));
            if (popup) {
              controller.attachToBrowser(this.docShell, popup.QueryInterface(Components.interfaces.nsIAutoCompletePopup));
              this.mFormFillAttached = true;
            }
          }
          ]]>
        </body>
      </method>

      <method name="detachFormFill">
        <body>
          <![CDATA[
          if (this.mFormFillAttached) {
            // hoop up the form fill autocomplete controller
            var controller = Components.classes["@mozilla.org/satchel/form-fill-controller;1"].
                               getService(Components.interfaces.nsIFormFillController);
            controller.detachFromBrowser(this.docShell);
            
            this.mFormFillAttached = false;
          }
          ]]>
        </body>
      </method>
      
      <method name="findChildShell">
        <parameter name="aDocShell"/>
        <parameter name="aSoughtURI"/>
        <body>
          <![CDATA[
            if (aDocShell.QueryInterface(Components.interfaces.nsIWebNavigation)
                         .currentURI.spec == aSoughtURI.spec)
              return aDocShell;
            var node = aDocShell.QueryInterface(
                                   Components.interfaces.nsIDocShellTreeNode);
            for (var i = 0; i < node.childCount; ++i) {
              var docShell = node.getChildAt(i);
              docShell = this.findChildShell(docShell, aSoughtURI);
              if (docShell)
                return docShell;
            }
            return null;
          ]]>
        </body>
      </method>

      <method name="onPageShow">
        <parameter name="aEvent"/>
        <body>
          <![CDATA[
            this.attachFormFill();
            if (this.pageReport) {
              var i = 0;
              while (i < this.pageReport.length) {
                // Filter out irrelevant reports.
                if (this.pageReport[i].requestingWindow &&
                    (this.pageReport[i].requestingWindow.document ==
                     this.pageReport[i].requestingDocument))
                  i++;
                else
                  this.pageReport.splice(i, 1);
              }
              if (this.pageReport.length == 0) {
                this.pageReport = null;
                this.updatePageReport();
              }
            }
         ]]>
        </body>
      </method>

      <method name="onPageHide">
        <parameter name="aEvent"/>
        <body>
          <![CDATA[
            if (this.pageReport) {
              this.pageReport = null;
              this.updatePageReport();
            }
            // Delete the feeds cache if we're hiding the topmost page
            // (as opposed to one of its iframes).
            if (this.feeds && aEvent.target == this.contentDocument)
              this.feeds = null;
            if (!this.docShell || !this.fastFind)
              return;
            var tabBrowser = this.getTabBrowser();
            if (!tabBrowser || tabBrowser.mCurrentBrowser == this)
              this.fastFind.setDocShell(this.docShell);

            
            if (this._scrollable) {
              var doc =
                this._scrollable.ownerDocument || this._scrollable.document;
              if (doc == aEvent.target) {
                this._autoScrollPopup.hidePopup();
              }
            }
         ]]>
        </body>
      </method>

      <method name="updatePageReport">
        <body>
          <![CDATA[
            var event = document.createEvent("Events");
            event.initEvent("DOMUpdatePageReport", true, true);
            this.dispatchEvent(event);
          ]]>
        </body>
      </method>

      <method name="onPopupBlocked">
        <parameter name="evt"/>
        <body>
          <![CDATA[
            if (!this.pageReport) {
              this.pageReport = new Array();
            }

            var obj = { requestingWindow: evt.requestingWindow,
                        // Record the current document in the requesting window
                        // before it can change.
                        requestingDocument: evt.requestingWindow.document,
                        popupWindowURI: evt.popupWindowURI,
                        popupWindowFeatures: evt.popupWindowFeatures,
                        popupWindowName: evt.popupWindowName };

            this.pageReport.push(obj);
            this.pageReport.reported = false;
            this.updatePageReport();
          ]]> 
        </body>
      </method>

      <field name="pageReport">null</field>

      <property name="securityUI">
        <getter>
          <![CDATA[
            if (!this.docShell.securityUI) {
              const SECUREBROWSERUI_CONTRACTID = "@mozilla.org/secure_browser_ui;1";
              if (!this.hasAttribute("disablesecurity") &&
                  SECUREBROWSERUI_CONTRACTID in Components.classes) {
                var securityUI = Components.classes[SECUREBROWSERUI_CONTRACTID]
                                           .createInstance(Components.interfaces.nsISecureBrowserUI);
                securityUI.init(this.contentWindow);
              }
            }
            
            return this.docShell.securityUI;
          ]]>
        </getter>
        <setter>
          <![CDATA[
            this.docShell.securityUI = val;
          ]]>
        </setter>
      </property>

      <!--
        This field tracks the location bar state. The value that the user typed
        in to the location bar may not be changed while this field is zero.
        However invoking a load will temporarily increase this field to allow
        the location bar to be updated to the new URL.

        Case 1: Anchor scroll
          The user appends the anchor to the URL. This sets the location bar
          into typed state, and disables changes to the location bar. The user
          then requests the scroll. loadURIWithFlags temporarily increases the
          flag by 1 so that the anchor scroll's location change resets the
          location bar state.

        Case 2: Interrupted load
          The user types in and submits the URL. This triggers an asynchronous
          network load which increases the flag by 2. (The temporary increase
          from loadURIWithFlags is not noticeable in this case.) When the load
          is interrupted the flag returns to zero, and the location bar stays
          in typed state.

        Case 3: New load
          This works like case 2, but as the load is not interrupted the
          location changes while the flag is still 2 thus resetting the
          location bar state.

        Case 4: Corrected load
          This is a combination of case 2 and case 3, except that the original
          load is interrupted by the new load. Normally cancelling and starting
          a new load would reset the flag to 0 and then increase it to 2 again.
          However both actions occur as a consequence of the loadURIWithFlags
          invocation, which adds its temporary increase in to the mix. Since
          the new URL would have been typed in the flag would have been reset
          before loadURIWithFlags incremented it. The interruption resets the
          flag to 0 and increases it to 2. Although loadURIWithFlags will
          decrement the flag it remains at 1 thus allowing the location bar
          state to be reset when the new load changes the location.
          This case also applies when loading into a new browser, as this
          interrupts the default load of about:blank.
      -->
      <field name="userTypedClear">
        1
      </field>

      <field name="_userTypedValue">
        null
      </field>

      <property name="userTypedValue"
                onget="return this._userTypedValue;"
                onset="this.userTypedClear = 0; return this._userTypedValue = val;"/>

      <field name="mFormFillAttached">
        false
      </field>
      
      <field name="isShowingMessage">
        false
      </field>

      <field name="droppedLinkHandler">
        null
      </field>

      <field name="mIconURL">null</field>

      <!-- This is managed by the tabbrowser -->
      <field name="lastURI">null</field>

      <field name="mDestroyed">false</field>

      <constructor>
        <![CDATA[
          try {
            if (!this.hasAttribute("disablehistory")) {
              var os = Components.classes["@mozilla.org/observer-service;1"]
                                 .getService(Components.interfaces.nsIObserverService);
              os.addObserver(this, "browser:purge-session-history", false);
              // wire up session history
              this.webNavigation.sessionHistory = 
                      Components.classes["@mozilla.org/browser/shistory;1"]
                                .createInstance(Components.interfaces.nsISHistory);
              // enable global history
              if (this.docShell)
                this.docShell.QueryInterface(Components.interfaces.nsIDocShellHistory).useGlobalHistory = true;
            }
          }
          catch (e) {
            Components.utils.reportError(e);
          }
          try {
            var securityUI = this.securityUI;
          }
          catch (e) {
          }

          // Listen for first load for lazy attachment to form fill controller
          this.addEventListener("pageshow", this.onPageShow, true);
          this.addEventListener("pagehide", this.onPageHide, true);
          this.addEventListener("DOMPopupBlocked", this.onPopupBlocked, true);
        ]]>
      </constructor>
      
      <destructor>
        <![CDATA[
          this.destroy();
        ]]>
      </destructor>

      <!-- This is necessary because the destructor doesn't always get called when
           we are removed from a tabbrowser. This will be explicitly called by tabbrowser -->
      <method name="destroy">
        <body>
          <![CDATA[
          if (this.mDestroyed)
            return;
          this.mDestroyed = true;

          if (!this.hasAttribute("disablehistory")) {
            var os = Components.classes["@mozilla.org/observer-service;1"]
                               .getService(Components.interfaces.nsIObserverService);
            try {
              os.removeObserver(this, "browser:purge-session-history");
            } catch (ex) {
              // It's not clear why this sometimes throws an exception.
            }
          }

          this.detachFormFill();
          
          this._fastFind = null;
          this._webBrowserFind = null;
          
          // The feeds cache can keep the document inside this browser alive.
          this.feeds = null;

          this.lastURI = null;

          this.removeEventListener("pageshow", this.onPageShow, true);
          this.removeEventListener("pagehide", this.onPageHide, true);
          this.removeEventListener("DOMPopupBlocked", this.onPopupBlocked, true);

          if (this._autoScrollNeedsCleanup) {
            // we polluted the global scope, so clean it up
            this._autoScrollPopup.parentNode.removeChild(this._autoScrollPopup);
          }
          ]]>
        </body>
      </method>
      
      <method name="observe">
        <parameter name="aSubject"/>
        <parameter name="aTopic"/>
        <parameter name="aState"/>
        <body>
          <![CDATA[
            if (aTopic != "browser:purge-session-history" || !this.sessionHistory)
              return;
              
            // place the entry at current index at the end of the history list, so it won't get removed
            if (this.sessionHistory.index < this.sessionHistory.count - 1) {
              var indexEntry = this.sessionHistory.getEntryAtIndex(this.sessionHistory.index, false);
              this.sessionHistory.QueryInterface(Components.interfaces.nsISHistoryInternal);
              indexEntry.QueryInterface(Components.interfaces.nsISHEntry);
              this.sessionHistory.addEntry(indexEntry, true);
            }
            
            var purge = this.sessionHistory.count;
            if (this.currentURI != "about:blank")
              --purge; // Don't remove the page the user's staring at from shistory
            
            if (purge > 0)
              this.sessionHistory.PurgeHistory(purge);
          ]]>
        </body>
      </method>

      <field name="_AUTOSCROLL_SNAP">10</field>
      <field name="_scrollable">null</field>
      <field name="_startX">null</field>
      <field name="_startY">null</field>
      <field name="_screenX">null</field>
      <field name="_screenY">null</field>
      <field name="_lastFrame">null</field>
      <field name="_autoScrollPopup">null</field>
      <field name="_autoScrollNeedsCleanup">false</field>

      <method name="stopScroll">
        <body>
          <![CDATA[
            if (this._scrollable) {
              this._scrollable = null;
              window.removeEventListener("mousemove", this, true);
              window.removeEventListener("mousedown", this, true);
              window.removeEventListener("mouseup", this, true);
              window.removeEventListener("contextmenu", this, true);
              window.removeEventListener("keydown", this, true);
              window.removeEventListener("keypress", this, true);
              window.removeEventListener("keyup", this, true);
              window.removeEventListener("MozBeforePaint", this, true);
            }
         ]]>
       </body>
     </method>

      <method name="_createAutoScrollPopup">
        <body>
          <![CDATA[
            const XUL_NS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
            var popup = document.createElementNS(XUL_NS, "panel");
            popup.className = "autoscroller";
            return popup;
          ]]>
        </body>
      </method>
     
      <method name="startScroll">
        <parameter name="event"/>
        <body>
          <![CDATA[
            if (!this._autoScrollPopup) {
              if (this.hasAttribute("autoscrollpopup")) {
                // our creator provided a popup to share
                this._autoScrollPopup = document.getElementById(this.getAttribute("autoscrollpopup"));
              }
              else {
                // we weren't provided a popup; we have to use the global scope
                this._autoScrollPopup = this._createAutoScrollPopup();
                document.documentElement.appendChild(this._autoScrollPopup);
                this._autoScrollNeedsCleanup = true;
              }
            }

            this._autoScrollPopup.addEventListener("popuphidden", this, true);

            // we need these attributes so themers don't need to create per-platform packages
            if (screen.colorDepth > 8) { // need high color for transparency
              // Exclude second-rate platforms
              this._autoScrollPopup.setAttribute("transparent", !/BeOS|OS\/2/.test(navigator.appVersion));
              // Enable translucency on Windows and Mac
              this._autoScrollPopup.setAttribute("translucent", /Win|Mac/.test(navigator.platform));
            }

            // this is a list of overflow property values that allow scrolling
            const scrollingAllowed = ['scroll', 'auto'];

            // go upward in the DOM and find any parent element that has a overflow
            // area and can therefore be scrolled
            for (this._scrollable = event.originalTarget; this._scrollable;
                 this._scrollable = this._scrollable.parentNode) {
              // do not use overflow based autoscroll for <html> Elements
              // or non-html elements such as svg or Document nodes
              // also make sure to skip select elements that are not multiline
              if (!(this._scrollable instanceof HTMLElement) ||
                  (this._scrollable instanceof HTMLHtmlElement) ||
                  ((this._scrollable instanceof HTMLSelectElement) && !this._scrollable.multiple)) {
                continue;
              }

              var overflowx = this._scrollable.ownerDocument.defaultView
                                  .getComputedStyle(this._scrollable, '')
                                  .getPropertyValue('overflow-x');
              var overflowy = this._scrollable.ownerDocument.defaultView
                                  .getComputedStyle(this._scrollable, '')
                                  .getPropertyValue('overflow-y');
              // we already discarded non-multiline selects so allow vertical
              // scroll for multiline ones directly without checking for a
              // overflow property
              var scrollVert = this._scrollable.clientHeight > 0 &&
                               this._scrollable.scrollHeight > this._scrollable.clientHeight &&
                               (this._scrollable instanceof HTMLSelectElement ||
                                scrollingAllowed.indexOf(overflowy) >= 0);

              // do not allow horizontal scrolling for select elements, it leads
              // to visual artifacts and is not the expected behavior anyway
              if (!(this._scrollable instanceof HTMLSelectElement) &&
                  this._scrollable.clientWidth > 0 &&
                  this._scrollable.scrollWidth > this._scrollable.clientWidth &&
                  scrollingAllowed.indexOf(overflowx) >= 0) {
                this._autoScrollPopup.setAttribute("scrolldir", scrollVert ? "NSEW" : "EW");
                break;
              }
              else if (scrollVert) {
                this._autoScrollPopup.setAttribute("scrolldir", "NS");
                break;
              }
            }

            if (!this._scrollable) {
              this._scrollable = event.originalTarget.ownerDocument.defaultView;
              if (this._scrollable.scrollMaxX > 0) {
                this._autoScrollPopup.setAttribute("scrolldir", this._scrollable.scrollMaxY > 0 ? "NSEW" : "EW");
              }
              else if (this._scrollable.scrollMaxY > 0) {
                this._autoScrollPopup.setAttribute("scrolldir", "NS");
              }
              else {
                this._scrollable = null; // abort scrolling
                return;
              }
            }

            this._autoScrollPopup.showPopup(document.documentElement,
                                            event.screenX,
                                            event.screenY,
                                            "popup", null, null);
            this._ignoreMouseEvents = true;
            this._startX = event.screenX;
            this._startY = event.screenY;
            this._screenX = event.screenX;
            this._screenY = event.screenY;
            this._scrollErrorX = 0;
            this._scrollErrorY = 0;
            this._lastFrame = window.mozAnimationStartTime;

            window.addEventListener("mousemove", this, true);
            window.addEventListener("mousedown", this, true);
            window.addEventListener("mouseup", this, true);
            window.addEventListener("contextmenu", this, true);
            window.addEventListener("keydown", this, true);
            window.addEventListener("keypress", this, true);
            window.addEventListener("keyup", this, true);
            window.addEventListener("MozBeforePaint", this, true);

            window.mozRequestAnimationFrame();
         ]]>
       </body>
     </method>

     <method name="_roundToZero">
       <parameter name="num"/>
       <body>
         <![CDATA[
            if (num > 0)
              return Math.floor(num);
            return Math.ceil(num);
         ]]>
       </body>
     </method>

     <method name="_accelerate">
       <parameter name="curr"/>
       <parameter name="start"/>
       <body>
         <![CDATA[
            const speed = 12;
            var val = (curr - start) / speed;

            if (val > 1)
              return val * Math.sqrt(val) - 1;
            if (val < -1)
              return val * Math.sqrt(-val) + 1;
            return 0;
         ]]>
       </body>
     </method>

     <method name="autoScrollLoop">
       <parameter name="timestamp"/>
       <body>
         <![CDATA[
           // avoid long jumps when the browser hangs for more than
           // |maxTimeDelta| ms
           const maxTimeDelta = 100;
           var timeDelta = Math.min(maxTimeDelta, timestamp - this._lastFrame);
           // we used to scroll |_accelerate()| pixels every 20ms (50fps)
           var timeCompensation = timeDelta / 20;
           this._lastFrame = timestamp;

           var actualScrollX = 0;
           var actualScrollY = 0;
           // don't bother scrolling vertically when the scrolldir is only horizontal
           // and the other way around
           var scrolldir = this._autoScrollPopup.getAttribute("scrolldir");
           if (scrolldir != 'EW') {
             var y = this._accelerate(this._screenY, this._startY) * timeCompensation;
             var desiredScrollY = this._scrollErrorY + y;
             actualScrollY = this._roundToZero(desiredScrollY);
             this._scrollErrorY = (desiredScrollY - actualScrollY);
           }
           if (scrolldir != 'NS') {
             var x = this._accelerate(this._screenX, this._startX) * timeCompensation;
             var desiredScrollX = this._scrollErrorX + x;
             actualScrollX = this._roundToZero(desiredScrollX);
             this._scrollErrorX = (desiredScrollX - actualScrollX);
           }

           if (this._scrollable instanceof Window)
             this._scrollable.scrollBy(actualScrollX, actualScrollY);
           else { // an element with overflow
             this._scrollable.scrollLeft += actualScrollX;
             this._scrollable.scrollTop += actualScrollY;
           }
           window.mozRequestAnimationFrame();
         ]]>
       </body>
     </method>
     <method name="isAutoscrollBlocker">
       <parameter name="node"/>
       <body>
         <![CDATA[
           var mmPaste = false;
           var mmScrollbarPosition = false;

           try {
             mmPaste = this.mPrefs.getBoolPref("middlemouse.paste");
           }
           catch (ex) {
           }

           try {
             mmScrollbarPosition = this.mPrefs.getBoolPref("middlemouse.scrollbarPosition");
           }
           catch (ex) {
           }

           while (node) {
             if ((node instanceof HTMLAnchorElement || node instanceof HTMLAreaElement) && node.hasAttribute("href"))
               return true;

             if (mmPaste && (node instanceof HTMLInputElement || node instanceof HTMLTextAreaElement))
               return true;

             if (node instanceof XULElement && mmScrollbarPosition
                 && (node.localName == "scrollbar" || node.localName == "scrollcorner"))
               return true;

             node = node.parentNode;
           }
           return false;
         ]]>
       </body>
     </method>

      <method name="handleEvent">
        <parameter name="aEvent"/>
        <body>
        <![CDATA[
          if (this._scrollable) {
            switch(aEvent.type) {
              case "MozBeforePaint":
                this.autoScrollLoop(aEvent.timeStamp);
                break;
              case "mousemove": {
                this._screenX = aEvent.screenX;
                this._screenY = aEvent.screenY;

                var x = this._screenX - this._startX;
                var y = this._screenY - this._startY;
        
                if ((x > this._AUTOSCROLL_SNAP || x < -this._AUTOSCROLL_SNAP) ||
                    (y > this._AUTOSCROLL_SNAP || y < -this._AUTOSCROLL_SNAP))
                  this._ignoreMouseEvents = false;
                break;
              }
              case "mouseup":
              case "mousedown":
              case "contextmenu": {
                if (!this._ignoreMouseEvents)
                  this._autoScrollPopup.hidePopup();
                this._ignoreMouseEvents = false;
                break;
              }
              case "popuphidden": {
                this._autoScrollPopup.removeEventListener("popuphidden", this, true);
                this.stopScroll();
                break;
              }
              case "keypress": {
                if (aEvent.keyCode == aEvent.DOM_VK_ESCAPE) {
                  // the escape key will be processed by
                  // nsXULPopupManager::KeyPress and the panel will be closed.
                  // So, nothing to do here.
                  break;
                }
                // don't break here. we need to eat keypress events.
              }
              case "keydown":
              case "keyup": {
                // All keyevents should be eaten here during autoscrolling.
                aEvent.stopPropagation();
                aEvent.preventDefault();
                break;
              }
            }
          }
        ]]>
        </body>
      </method>

      <method name="swapDocShells">
        <parameter name="aOtherBrowser"/>
        <body>
        <![CDATA[
          // We need to swap fields that are tied to our docshell or related to
          // the loaded page
          // Fields which are built as a result of notifactions (pageshow/hide,
          // DOMLinkAdded/Removed, onStateChange) should not be swapped here,
          // because these notifications are dispatched again once the docshells
          // are swapped.
          var fieldsToSwap = [ "_docShell", "_webBrowserFind", "_contentWindow", "_webNavigation"];

          var ourTabBrowser = this.getTabBrowser();

          // _fastFind is tied to the docshell if we don't have a tabbrowser
          if ((ourTabBrowser != null) !=
              (aOtherBrowser.getTabBrowser() != null))
            throw "Unable to perform swap on <browsers> if one is in a <tabbrowser> and one is not";

          if (!ourTabBrowser)
            fieldsToSwap.push("_fastFind");

          var ourFieldValues = {};
          var otherFieldValues = {};
          for each (var field in fieldsToSwap) {
            ourFieldValues[field] = this[field];
            otherFieldValues[field] = aOtherBrowser[field];
          }
          this.QueryInterface(Components.interfaces.nsIFrameLoaderOwner)
              .swapFrameLoaders(aOtherBrowser);
          for each (var field in fieldsToSwap) {
            this[field] = otherFieldValues[field];
            aOtherBrowser[field] = ourFieldValues[field];
          }
        ]]>
        </body>
      </method>
    </implementation>

    <handlers>
      <handler event="keypress" keycode="VK_F7" group="system">
        <![CDATA[
          if (event.getPreventDefault() || !event.isTrusted)
            return;

          var isEnabled = this.mPrefs.getBoolPref("accessibility.browsewithcaret_shortcut.enabled");
          if (!isEnabled)
            return;

          // Toggle browse with caret mode
          var browseWithCaretOn = false;
          var warn = true;

          try {
            warn = this.mPrefs.getBoolPref("accessibility.warn_on_browsewithcaret");
          } catch (ex) {
          }

          try {
            browseWithCaretOn = this.mPrefs.getBoolPref("accessibility.browsewithcaret");
          } catch (ex) {
          }
          if (warn && !browseWithCaretOn) {
            var checkValue = {value:false};
            promptService = Components.classes["@mozilla.org/embedcomp/prompt-service;1"].getService(Components.interfaces.nsIPromptService);

            var buttonPressed = promptService.confirmEx(window, 
              this.mStrBundle.GetStringFromName('browsewithcaret.checkWindowTitle'), 
              this.mStrBundle.GetStringFromName('browsewithcaret.checkLabel'),
              promptService.STD_YES_NO_BUTTONS,
              null, null, null, this.mStrBundle.GetStringFromName('browsewithcaret.checkMsg'),
              checkValue);
            if (buttonPressed != 0)
              return;
            if (checkValue.value) {
              try {
                this.mPrefs.setBoolPref("accessibility.warn_on_browsewithcaret", false);
              }
              catch (ex) {
              }
            }
          }

          // Toggle the pref
          try {
            this.mPrefs.setBoolPref("accessibility.browsewithcaret",!browseWithCaretOn);
          } catch (ex) {
          }
        ]]>
      </handler>
      <handler event="mousedown" phase="capturing">
        <![CDATA[
          if (!this._scrollable && event.button == 1) {
            if (!this.autoscrollEnabled ||
                this.isAutoscrollBlocker(event.originalTarget))
              return;

            this.startScroll(event);
          }
        ]]>
      </handler>
      <handler event="dragover" group="system">
      <![CDATA[
        if (!this.droppedLinkHandler || event.getPreventDefault())
          return;

        // For drags that appear to be internal text (for example, tab drags),
        // set the dropEffect to 'none'. This prevents the drop even if some
        // other listener cancelled the event.
        var types = event.dataTransfer.types;
        if (types.contains("text/x-moz-text-internal") && !types.contains("text/plain")) {
          event.dataTransfer.dropEffect = "none";
          event.stopPropagation();
          event.preventDefault();
        }

        let linkHandler = Components.classes["@mozilla.org/content/dropped-link-handler;1"].
                            getService(Components.interfaces.nsIDroppedLinkHandler);
        if (linkHandler.canDropLink(event, false))
          event.preventDefault();
      ]]>
      </handler>
      <handler event="drop" group="system">
      <![CDATA[
        if (!this.droppedLinkHandler || event.getPreventDefault())
          return;

        let name = { };
        let linkHandler = Components.classes["@mozilla.org/content/dropped-link-handler;1"].
                            getService(Components.interfaces.nsIDroppedLinkHandler);
        try {
          var uri = linkHandler.dropLink(event, name);
        } catch (ex) {
          return;
        }

        // don't allow dropping javascript or data urls
        if (/^\s*(javascript|data):/.test(uri))
          return;

        if (uri) {
          this.droppedLinkHandler(event, uri, name.value);
        }
      ]]>
      </handler>
    </handlers>

  </binding>

</bindings>
