michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0: * License, v. 2.0. If a copy of the MPL was not distributed with this file,
michael@0: * You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: "use strict";
michael@0: 
michael@0: this.EXPORTED_SYMBOLS = ["PageStyle"];
michael@0: 
michael@0: const Ci = Components.interfaces;
michael@0: 
michael@0: /**
michael@0:  * The external API exported by this module.
michael@0:  */
michael@0: this.PageStyle = Object.freeze({
michael@0:   collect: function (docShell, frameTree) {
michael@0:     return PageStyleInternal.collect(docShell, frameTree);
michael@0:   },
michael@0: 
michael@0:   restore: function (docShell, frameList, pageStyle) {
michael@0:     PageStyleInternal.restore(docShell, frameList, pageStyle);
michael@0:   },
michael@0: 
michael@0:   restoreTree: function (docShell, data) {
michael@0:     PageStyleInternal.restoreTree(docShell, data);
michael@0:   }
michael@0: });
michael@0: 
michael@0: // Signifies that author style level is disabled for the page.
michael@0: const NO_STYLE = "_nostyle";
michael@0: 
michael@0: let PageStyleInternal = {
michael@0:   /**
michael@0:    * Collects the selected style sheet sets for all reachable frames.
michael@0:    */
michael@0:   collect: function (docShell, frameTree) {
michael@0:     let result = frameTree.map(({document: doc}) => {
michael@0:       let style;
michael@0: 
michael@0:       if (doc) {
michael@0:         // http://dev.w3.org/csswg/cssom/#persisting-the-selected-css-style-sheet-set
michael@0:         style = doc.selectedStyleSheetSet || doc.lastStyleSheetSet;
michael@0:       }
michael@0: 
michael@0:       return style ? {pageStyle: style} : null;
michael@0:     });
michael@0: 
michael@0:     let markupDocumentViewer =
michael@0:       docShell.contentViewer.QueryInterface(Ci.nsIMarkupDocumentViewer);
michael@0: 
michael@0:     if (markupDocumentViewer.authorStyleDisabled) {
michael@0:       result = result || {};
michael@0:       result.disabled = true;
michael@0:     }
michael@0: 
michael@0:     return result && Object.keys(result).length ? result : null;
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Restore the selected style sheet of all the frames in frameList
michael@0:    * to match |pageStyle|.
michael@0:    * @param docShell the root docshell of all the frames
michael@0:    * @param frameList a list of [frame, data] pairs, where frame is a
michael@0:    * DOM window and data is the session restore data associated with
michael@0:    * it.
michael@0:    * @param pageStyle the title of the style sheet to apply
michael@0:    */
michael@0:   restore: function (docShell, frameList, pageStyle) {
michael@0:     let disabled = pageStyle == NO_STYLE;
michael@0: 
michael@0:     let markupDocumentViewer =
michael@0:       docShell.contentViewer.QueryInterface(Ci.nsIMarkupDocumentViewer);
michael@0:     markupDocumentViewer.authorStyleDisabled = disabled;
michael@0: 
michael@0:     for (let [frame, data] of frameList) {
michael@0:       Array.forEach(frame.document.styleSheets, function(aSS) {
michael@0:         aSS.disabled = aSS.title && aSS.title != pageStyle;
michael@0:       });
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Restores pageStyle data for the current frame hierarchy starting at the
michael@0:    * |docShell's| current DOMWindow using the given pageStyle |data|.
michael@0:    *
michael@0:    * Warning: If the current frame hierarchy doesn't match that of the given
michael@0:    * |data| object we will silently discard data for unreachable frames. We may
michael@0:    * as well assign page styles to the wrong frames if some were reordered or
michael@0:    * removed.
michael@0:    *
michael@0:    * @param docShell (nsIDocShell)
michael@0:    * @param data (object)
michael@0:    *        {
michael@0:    *          disabled: true, // when true, author styles will be disabled
michael@0:    *          pageStyle: "Dusk",
michael@0:    *          children: [
michael@0:    *            null,
michael@0:    *            {pageStyle: "Mozilla", children: [ ... ]}
michael@0:    *          ]
michael@0:    *        }
michael@0:    */
michael@0:   restoreTree: function (docShell, data) {
michael@0:     let disabled = data.disabled || false;
michael@0:     let markupDocumentViewer =
michael@0:       docShell.contentViewer.QueryInterface(Ci.nsIMarkupDocumentViewer);
michael@0:     markupDocumentViewer.authorStyleDisabled = disabled;
michael@0: 
michael@0:     function restoreFrame(root, data) {
michael@0:       if (data.hasOwnProperty("pageStyle")) {
michael@0:         root.document.selectedStyleSheetSet = data.pageStyle;
michael@0:       }
michael@0: 
michael@0:       if (!data.hasOwnProperty("children")) {
michael@0:         return;
michael@0:       }
michael@0: 
michael@0:       let frames = root.frames;
michael@0:       data.children.forEach((child, index) => {
michael@0:         if (child && index < frames.length) {
michael@0:           restoreFrame(frames[index], child);
michael@0:         }
michael@0:       });
michael@0:     }
michael@0: 
michael@0:     let ifreq = docShell.QueryInterface(Ci.nsIInterfaceRequestor);
michael@0:     restoreFrame(ifreq.getInterface(Ci.nsIDOMWindow), data);
michael@0:   }
michael@0: };