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| -rw-r--r-- | toolkit/modules/FormLikeFactory.sys.mjs | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/toolkit/modules/FormLikeFactory.sys.mjs b/toolkit/modules/FormLikeFactory.sys.mjs new file mode 100644 index 0000000000..9c175241aa --- /dev/null +++ b/toolkit/modules/FormLikeFactory.sys.mjs @@ -0,0 +1,193 @@ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs"; + +/** + * A factory to generate FormLike objects that represent a set of related fields + * which aren't necessarily marked up with a <form> element. FormLike's emulate + * the properties of an HTMLFormElement which are relevant to form tasks. + */ +export let FormLikeFactory = { + _propsFromForm: ["action", "autocomplete", "ownerDocument"], + + /** + * Create a FormLike object from a <form>. + * + * @param {HTMLFormElement} aForm + * @return {FormLike} + * @throws Error if aForm isn't an HTMLFormElement + */ + createFromForm(aForm) { + if (!HTMLFormElement.isInstance(aForm)) { + throw new Error("createFromForm: aForm must be a HTMLFormElement"); + } + + let formLike = { + elements: [...aForm.elements], + rootElement: aForm, + }; + + for (let prop of this._propsFromForm) { + formLike[prop] = aForm[prop]; + } + + this._addToJSONProperty(formLike); + + return formLike; + }, + + /** + * Create a FormLike object from an <input>/<select> in a document. + * + * If the field is in a <form>, construct the FormLike from the form. + * Otherwise, create a FormLike with a rootElement (wrapper) according to + * heuristics. Currently all <input>/<select> not in a <form> are one FormLike + * but this shouldn't be relied upon as the heuristics may change to detect + * multiple "forms" (e.g. registration and login) on one page with a <form>. + * + * Note that two FormLikes created from the same field won't return the same FormLike object. + * Use the `rootElement` property on the FormLike as a key instead. + * + * @param {HTMLInputElement|HTMLSelectElement} aField - an <input> or <select> field in a document + * @return {FormLike} + * @throws Error if aField isn't a password or username field in a document + */ + createFromField(aField) { + if ( + (!HTMLInputElement.isInstance(aField) && + !HTMLSelectElement.isInstance(aField)) || + !aField.ownerDocument + ) { + throw new Error("createFromField requires a field in a document"); + } + + let rootElement = this.findRootForField(aField); + if (HTMLFormElement.isInstance(rootElement)) { + return this.createFromForm(rootElement); + } + + let doc = aField.ownerDocument; + + let formLike = { + action: doc.baseURI, + autocomplete: "on", + ownerDocument: doc, + rootElement, + }; + + // FormLikes can be created when fields are inserted into the DOM. When + // many, many fields are inserted one after the other, we create many + // FormLikes, and computing the elements list becomes more and more + // expensive. Making the elements list lazy means that it'll only + // be computed when it's eventually needed (if ever). + XPCOMUtils.defineLazyGetter(formLike, "elements", function () { + let elements = []; + for (let el of this.rootElement.querySelectorAll("input, select")) { + // Exclude elements inside the rootElement that are already in a <form> as + // they will be handled by their own FormLike. + if (!el.form) { + elements.push(el); + } + } + + return elements; + }); + + this._addToJSONProperty(formLike); + return formLike; + }, + + /** + * Find the closest <form> if any when aField is inside a ShadowRoot. + * + * @param {HTMLInputElement} aField - a password or username field in a document + * @return {HTMLFormElement|null} + */ + closestFormIgnoringShadowRoots(aField) { + let form = aField.closest("form"); + let current = aField; + while (!form) { + let shadowRoot = current.getRootNode(); + if (!ShadowRoot.isInstance(shadowRoot)) { + break; + } + let host = shadowRoot.host; + form = host.closest("form"); + current = host; + } + return form; + }, + + /** + * Determine the Element that encapsulates the related fields. For example, if + * a page contains a login form and a checkout form which are "submitted" + * separately, and the username field is passed in, ideally this would return + * an ancestor Element of the username and password fields which doesn't + * include any of the checkout fields. + * + * @param {HTMLInputElement|HTMLSelectElement} aField - a field in a document + * @return {HTMLElement} - the root element surrounding related fields + */ + findRootForField(aField) { + let form = aField.form || this.closestFormIgnoringShadowRoots(aField); + if (form) { + return form; + } + + return aField.ownerDocument.documentElement; + }, + + /** + * Add a `toJSON` property to a FormLike so logging which ends up going + * through dump doesn't include usless garbage from DOM objects. + */ + _addToJSONProperty(aFormLike) { + function prettyElementOutput(aElement) { + let idText = aElement.id ? "#" + aElement.id : ""; + let classText = ""; + for (let className of aElement.classList) { + classText += "." + className; + } + return `<${aElement.nodeName + idText + classText}>`; + } + + Object.defineProperty(aFormLike, "toJSON", { + value: () => { + let cleansed = {}; + for (let key of Object.keys(aFormLike)) { + let value = aFormLike[key]; + let cleansedValue = value; + + switch (key) { + case "elements": { + cleansedValue = []; + for (let element of value) { + cleansedValue.push(prettyElementOutput(element)); + } + break; + } + + case "ownerDocument": { + cleansedValue = { + location: { + href: value.location.href, + }, + }; + break; + } + + case "rootElement": { + cleansedValue = prettyElementOutput(value); + break; + } + } + + cleansed[key] = cleansedValue; + } + return cleansed; + }, + }); + }, +}; |