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 = ["FormData"];
michael@0: 
michael@0: const Cu = Components.utils;
michael@0: const Ci = Components.interfaces;
michael@0: 
michael@0: Cu.import("resource://gre/modules/Timer.jsm");
michael@0: Cu.import("resource://gre/modules/XPathGenerator.jsm");
michael@0: 
michael@0: /**
michael@0:  * Returns whether the given URL very likely has input
michael@0:  * fields that contain serialized session store data.
michael@0:  */
michael@0: function isRestorationPage(url) {
michael@0:   return url == "about:sessionrestore" || url == "about:welcomeback";
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * Returns whether the given form |data| object contains nested restoration
michael@0:  * data for a page like about:sessionrestore or about:welcomeback.
michael@0:  */
michael@0: function hasRestorationData(data) {
michael@0:   if (isRestorationPage(data.url) && data.id) {
michael@0:     return typeof(data.id.sessionData) == "object";
michael@0:   }
michael@0: 
michael@0:   return false;
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * Returns the given document's current URI and strips
michael@0:  * off the URI's anchor part, if any.
michael@0:  */
michael@0: function getDocumentURI(doc) {
michael@0:   return doc.documentURI.replace(/#.*$/, "");
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * The public API exported by this module that allows to collect
michael@0:  * and restore form data for a document and its subframes.
michael@0:  */
michael@0: this.FormData = Object.freeze({
michael@0:   collect: function (frame) {
michael@0:     return FormDataInternal.collect(frame);
michael@0:   },
michael@0: 
michael@0:   restore: function (frame, data) {
michael@0:     FormDataInternal.restore(frame, data);
michael@0:   },
michael@0: 
michael@0:   restoreTree: function (root, data) {
michael@0:     FormDataInternal.restoreTree(root, data);
michael@0:   }
michael@0: });
michael@0: 
michael@0: /**
michael@0:  * This module's internal API.
michael@0:  */
michael@0: let FormDataInternal = {
michael@0:   /**
michael@0:    * Collect form data for a given |frame| *not* including any subframes.
michael@0:    *
michael@0:    * The returned object may have an "id", "xpath", or "innerHTML" key or a
michael@0:    * combination of those three. Form data stored under "id" is for input
michael@0:    * fields with id attributes. Data stored under "xpath" is used for input
michael@0:    * fields that don't have a unique id and need to be queried using XPath.
michael@0:    * The "innerHTML" key is used for editable documents (designMode=on).
michael@0:    *
michael@0:    * Example:
michael@0:    *   {
michael@0:    *     id: {input1: "value1", input3: "value3"},
michael@0:    *     xpath: {
michael@0:    *       "/xhtml:html/xhtml:body/xhtml:input[@name='input2']" : "value2",
michael@0:    *       "/xhtml:html/xhtml:body/xhtml:input[@name='input4']" : "value4"
michael@0:    *     }
michael@0:    *   }
michael@0:    *
michael@0:    * @param  doc
michael@0:    *         DOMDocument instance to obtain form data for.
michael@0:    * @return object
michael@0:    *         Form data encoded in an object.
michael@0:    */
michael@0:   collect: function ({document: doc}) {
michael@0:     let formNodes = doc.evaluate(
michael@0:       XPathGenerator.restorableFormNodes,
michael@0:       doc,
michael@0:       XPathGenerator.resolveNS,
michael@0:       Ci.nsIDOMXPathResult.UNORDERED_NODE_ITERATOR_TYPE, null
michael@0:     );
michael@0: 
michael@0:     let node;
michael@0:     let ret = {};
michael@0: 
michael@0:     // Limit the number of XPath expressions for performance reasons. See
michael@0:     // bug 477564.
michael@0:     const MAX_TRAVERSED_XPATHS = 100;
michael@0:     let generatedCount = 0;
michael@0: 
michael@0:     while (node = formNodes.iterateNext()) {
michael@0:       let hasDefaultValue = true;
michael@0:       let value;
michael@0: 
michael@0:       // Only generate a limited number of XPath expressions for perf reasons
michael@0:       // (cf. bug 477564)
michael@0:       if (!node.id && generatedCount > MAX_TRAVERSED_XPATHS) {
michael@0:         continue;
michael@0:       }
michael@0: 
michael@0:       if (node instanceof Ci.nsIDOMHTMLInputElement ||
michael@0:           node instanceof Ci.nsIDOMHTMLTextAreaElement ||
michael@0:           node instanceof Ci.nsIDOMXULTextBoxElement) {
michael@0:         switch (node.type) {
michael@0:           case "checkbox":
michael@0:           case "radio":
michael@0:             value = node.checked;
michael@0:             hasDefaultValue = value == node.defaultChecked;
michael@0:             break;
michael@0:           case "file":
michael@0:             value = { type: "file", fileList: node.mozGetFileNameArray() };
michael@0:             hasDefaultValue = !value.fileList.length;
michael@0:             break;
michael@0:           default: // text, textarea
michael@0:             value = node.value;
michael@0:             hasDefaultValue = value == node.defaultValue;
michael@0:             break;
michael@0:         }
michael@0:       } else if (!node.multiple) {
michael@0:         // <select>s without the multiple attribute are hard to determine the
michael@0:         // default value, so assume we don't have the default.
michael@0:         hasDefaultValue = false;
michael@0:         value = { selectedIndex: node.selectedIndex, value: node.value };
michael@0:       } else {
michael@0:         // <select>s with the multiple attribute are easier to determine the
michael@0:         // default value since each <option> has a defaultSelected property
michael@0:         let options = Array.map(node.options, opt => {
michael@0:           hasDefaultValue = hasDefaultValue && (opt.selected == opt.defaultSelected);
michael@0:           return opt.selected ? opt.value : -1;
michael@0:         });
michael@0:         value = options.filter(ix => ix > -1);
michael@0:       }
michael@0: 
michael@0:       // In order to reduce XPath generation (which is slow), we only save data
michael@0:       // for form fields that have been changed. (cf. bug 537289)
michael@0:       if (hasDefaultValue) {
michael@0:         continue;
michael@0:       }
michael@0: 
michael@0:       if (node.id) {
michael@0:         ret.id = ret.id || {};
michael@0:         ret.id[node.id] = value;
michael@0:       } else {
michael@0:         generatedCount++;
michael@0:         ret.xpath = ret.xpath || {};
michael@0:         ret.xpath[XPathGenerator.generate(node)] = value;
michael@0:       }
michael@0:     }
michael@0: 
michael@0:     // designMode is undefined e.g. for XUL documents (as about:config)
michael@0:     if ((doc.designMode || "") == "on" && doc.body) {
michael@0:       ret.innerHTML = doc.body.innerHTML;
michael@0:     }
michael@0: 
michael@0:     // Return |null| if no form data has been found.
michael@0:     if (Object.keys(ret).length === 0) {
michael@0:       return null;
michael@0:     }
michael@0: 
michael@0:     // Store the frame's current URL with its form data so that we can compare
michael@0:     // it when restoring data to not inject form data into the wrong document.
michael@0:     ret.url = getDocumentURI(doc);
michael@0: 
michael@0:     // We want to avoid saving data for about:sessionrestore as a string.
michael@0:     // Since it's stored in the form as stringified JSON, stringifying further
michael@0:     // causes an explosion of escape characters. cf. bug 467409
michael@0:     if (isRestorationPage(ret.url)) {
michael@0:       ret.id.sessionData = JSON.parse(ret.id.sessionData);
michael@0:     }
michael@0: 
michael@0:     return ret;
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Restores form |data| for the given frame. The data is expected to be in
michael@0:    * the same format that FormData.collect() returns.
michael@0:    *
michael@0:    * @param frame (DOMWindow)
michael@0:    *        The frame to restore form data to.
michael@0:    * @param data (object)
michael@0:    *        An object holding form data.
michael@0:    */
michael@0:   restore: function ({document: doc}, data) {
michael@0:     // Don't restore any data for the given frame if the URL
michael@0:     // stored in the form data doesn't match its current URL.
michael@0:     if (!data.url || data.url != getDocumentURI(doc)) {
michael@0:       return;
michael@0:     }
michael@0: 
michael@0:     // For about:{sessionrestore,welcomeback} we saved the field as JSON to
michael@0:     // avoid nested instances causing humongous sessionstore.js files.
michael@0:     // cf. bug 467409
michael@0:     if (hasRestorationData(data)) {
michael@0:       data.id.sessionData = JSON.stringify(data.id.sessionData);
michael@0:     }
michael@0: 
michael@0:     if ("id" in data) {
michael@0:       let retrieveNode = id => doc.getElementById(id);
michael@0:       this.restoreManyInputValues(data.id, retrieveNode);
michael@0:     }
michael@0: 
michael@0:     if ("xpath" in data) {
michael@0:       let retrieveNode = xpath => XPathGenerator.resolve(doc, xpath);
michael@0:       this.restoreManyInputValues(data.xpath, retrieveNode);
michael@0:     }
michael@0: 
michael@0:     if ("innerHTML" in data) {
michael@0:       // We know that the URL matches data.url right now, but the user
michael@0:       // may navigate away before the setTimeout handler runs. We do
michael@0:       // a simple comparison against savedURL to check for that.
michael@0:       let savedURL = doc.documentURI;
michael@0: 
michael@0:       setTimeout(() => {
michael@0:         if (doc.body && doc.designMode == "on" && doc.documentURI == savedURL) {
michael@0:           doc.body.innerHTML = data.innerHTML;
michael@0:         }
michael@0:       });
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Iterates the given form data, retrieving nodes for all the keys and
michael@0:    * restores their appropriate values.
michael@0:    *
michael@0:    * @param data (object)
michael@0:    *        A subset of the form data as collected by FormData.collect(). This
michael@0:    *        is either data stored under "id" or under "xpath".
michael@0:    * @param retrieve (function)
michael@0:    *        The function used to retrieve the input field belonging to a key
michael@0:    *        in the given |data| object.
michael@0:    */
michael@0:   restoreManyInputValues: function (data, retrieve) {
michael@0:     for (let key of Object.keys(data)) {
michael@0:       let input = retrieve(key);
michael@0:       if (input) {
michael@0:         this.restoreSingleInputValue(input, data[key]);
michael@0:       }
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Restores a given form value to a given DOMNode and takes care of firing
michael@0:    * the appropriate DOM event should the input's value change.
michael@0:    *
michael@0:    * @param  aNode
michael@0:    *         DOMNode to set form value on.
michael@0:    * @param  aValue
michael@0:    *         Value to set form element to.
michael@0:    */
michael@0:   restoreSingleInputValue: function (aNode, aValue) {
michael@0:     let eventType;
michael@0: 
michael@0:     if (typeof aValue == "string" && aNode.type != "file") {
michael@0:       // Don't dispatch an input event if there is no change.
michael@0:       if (aNode.value == aValue) {
michael@0:         return;
michael@0:       }
michael@0: 
michael@0:       aNode.value = aValue;
michael@0:       eventType = "input";
michael@0:     } else if (typeof aValue == "boolean") {
michael@0:       // Don't dispatch a change event for no change.
michael@0:       if (aNode.checked == aValue) {
michael@0:         return;
michael@0:       }
michael@0: 
michael@0:       aNode.checked = aValue;
michael@0:       eventType = "change";
michael@0:     } else if (aValue && aValue.selectedIndex >= 0 && aValue.value) {
michael@0:       // Don't dispatch a change event for no change
michael@0:       if (aNode.options[aNode.selectedIndex].value == aValue.value) {
michael@0:         return;
michael@0:       }
michael@0: 
michael@0:       // find first option with matching aValue if possible
michael@0:       for (let i = 0; i < aNode.options.length; i++) {
michael@0:         if (aNode.options[i].value == aValue.value) {
michael@0:           aNode.selectedIndex = i;
michael@0:           eventType = "change";
michael@0:           break;
michael@0:         }
michael@0:       }
michael@0:     } else if (aValue && aValue.fileList && aValue.type == "file" &&
michael@0:       aNode.type == "file") {
michael@0:       aNode.mozSetFileNameArray(aValue.fileList, aValue.fileList.length);
michael@0:       eventType = "input";
michael@0:     } else if (Array.isArray(aValue) && aNode.options) {
michael@0:       Array.forEach(aNode.options, function(opt, index) {
michael@0:         // don't worry about malformed options with same values
michael@0:         opt.selected = aValue.indexOf(opt.value) > -1;
michael@0: 
michael@0:         // Only fire the event here if this wasn't selected by default
michael@0:         if (!opt.defaultSelected) {
michael@0:           eventType = "change";
michael@0:         }
michael@0:       });
michael@0:     }
michael@0: 
michael@0:     // Fire events for this node if applicable
michael@0:     if (eventType) {
michael@0:       let doc = aNode.ownerDocument;
michael@0:       let event = doc.createEvent("UIEvents");
michael@0:       event.initUIEvent(eventType, true, true, doc.defaultView, 0);
michael@0:       aNode.dispatchEvent(event);
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Restores form data for the current frame hierarchy starting at |root|
michael@0:    * using the given form |data|.
michael@0:    *
michael@0:    * If the given |root| frame's hierarchy doesn't match that of the given
michael@0:    * |data| object we will silently discard data for unreachable frames. For
michael@0:    * security reasons we will never restore form data to the wrong frames as
michael@0:    * we bail out silently if the stored URL doesn't match the frame's current
michael@0:    * URL.
michael@0:    *
michael@0:    * @param root (DOMWindow)
michael@0:    * @param data (object)
michael@0:    *        {
michael@0:    *          formdata: {id: {input1: "value1"}},
michael@0:    *          children: [
michael@0:    *            {formdata: {id: {input2: "value2"}}},
michael@0:    *            null,
michael@0:    *            {formdata: {xpath: { ... }}, children: [ ... ]}
michael@0:    *          ]
michael@0:    *        }
michael@0:    */
michael@0:   restoreTree: function (root, data) {
michael@0:     // Don't restore any data for the root frame and its subframes if there
michael@0:     // is a URL stored in the form data and it doesn't match its current URL.
michael@0:     if (data.url && data.url != getDocumentURI(root.document)) {
michael@0:       return;
michael@0:     }
michael@0: 
michael@0:     if (data.url) {
michael@0:       this.restore(root, data);
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:     for (let index of Object.keys(data.children)) {
michael@0:       if (index < frames.length) {
michael@0:         this.restoreTree(frames[index], data.children[index]);
michael@0:       }
michael@0:     }
michael@0:   }
michael@0: };