path: root/toolkit/components/passwordmgr/LoginManagerChild.sys.mjs

/* 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/. */

/**
 * Module doing most of the content process work for the password manager.
 */

// Disable use-ownerGlobal since LoginForm doesn't have it.
/* eslint-disable mozilla/use-ownerGlobal */

const PASSWORD_INPUT_ADDED_COALESCING_THRESHOLD_MS = 1;
// The amount of time a context menu event supresses showing a
// popup from a focus event in ms. This matches the threshold in
// toolkit/components/satchel/nsFormFillController.cpp
const AUTOCOMPLETE_AFTER_RIGHT_CLICK_THRESHOLD_MS = 400;
const AUTOFILL_STATE = "autofill";

const SUBMIT_FORM_SUBMIT = 1;
const SUBMIT_PAGE_NAVIGATION = 2;
const SUBMIT_FORM_IS_REMOVED = 3;

const LOG_MESSAGE_FORM_SUBMISSION = "form submission";
const LOG_MESSAGE_FIELD_EDIT = "field edit";

export const AUTOFILL_RESULT = {
  FILLED: "filled",
  NO_PASSWORD_FIELD: "no_password_field",
  PASSWORD_DISABLED_READONLY: "password_disabled_readonly",
  NO_LOGINS_FIT: "no_logins_fit",
  NO_SAVED_LOGINS: "no_saved_logins",
  EXISTING_PASSWORD: "existing_password",
  EXISTING_USERNAME: "existing_username",
  MULTIPLE_LOGINS: "multiple_logins",
  NO_AUTOFILL_FORMS: "no_autofill_forms",
  AUTOCOMPLETE_OFF: "autocomplete_off",
  INSECURE: "insecure",
  PASSWORD_AUTOCOMPLETE_NEW_PASSWORD: "password_autocomplete_new_password",
  TYPE_NO_LONGER_PASSWORD: "type_no_longer_password",
  FORM_IN_CROSSORIGIN_SUBFRAME: "form_in_crossorigin_subframe",
  FILLED_USERNAME_ONLY_FORM: "filled_username_only_form",
};

import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs";
import { AppConstants } from "resource://gre/modules/AppConstants.sys.mjs";
import { PrivateBrowsingUtils } from "resource://gre/modules/PrivateBrowsingUtils.sys.mjs";
import { CreditCard } from "resource://gre/modules/CreditCard.sys.mjs";

const lazy = {};

ChromeUtils.defineESModuleGetters(lazy, {
  ContentDOMReference: "resource://gre/modules/ContentDOMReference.sys.mjs",
  DeferredTask: "resource://gre/modules/DeferredTask.sys.mjs",
  FormLikeFactory: "resource://gre/modules/FormLikeFactory.sys.mjs",
  FormScenarios: "resource://gre/modules/FormScenarios.sys.mjs",
  InsecurePasswordUtils: "resource://gre/modules/InsecurePasswordUtils.sys.mjs",
  LoginFormFactory: "resource://gre/modules/LoginFormFactory.sys.mjs",
  LoginHelper: "resource://gre/modules/LoginHelper.sys.mjs",
  LoginRecipesContent: "resource://gre/modules/LoginRecipes.sys.mjs",
  LoginManagerTelemetry: "resource://gre/modules/LoginManagerTelemetry.sys.mjs",
});

XPCOMUtils.defineLazyServiceGetter(
  lazy,
  "gFormFillService",
  "@mozilla.org/satchel/form-fill-controller;1",
  "nsIFormFillController"
);

ChromeUtils.defineLazyGetter(lazy, "log", () => {
  let logger = lazy.LoginHelper.createLogger("LoginManagerChild");
  return logger.log.bind(logger);
});

Services.cpmm.addMessageListener("clearRecipeCache", () => {
  lazy.LoginRecipesContent._clearRecipeCache();
});

let gLastRightClickTimeStamp = Number.NEGATIVE_INFINITY;

// Events on pages with Shadow DOM could return the shadow host element
// (aEvent.target) rather than the actual username or password field
// (aEvent.composedTarget).
// Only allow input elements (can be extended later) to avoid false negatives.
class WeakFieldSet extends WeakSet {
  add(value) {
    if (!HTMLInputElement.isInstance(value)) {
      throw new Error("Non-field type added to a WeakFieldSet");
    }
    super.add(value);
  }
}

const observer = {
  QueryInterface: ChromeUtils.generateQI([
    "nsIObserver",
    "nsIWebProgressListener",
    "nsISupportsWeakReference",
  ]),

  // nsIWebProgressListener
  onLocationChange(aWebProgress, aRequest, aLocation, aFlags) {
    // Only handle pushState/replaceState here.
    if (
      !(aFlags & Ci.nsIWebProgressListener.LOCATION_CHANGE_SAME_DOCUMENT) ||
      !(aWebProgress.loadType & Ci.nsIDocShell.LOAD_CMD_PUSHSTATE)
    ) {
      return;
    }

    const window = aWebProgress.DOMWindow;
    lazy.log(
      "onLocationChange handled:",
      aLocation.displaySpec,
      window.document
    );
    LoginManagerChild.forWindow(window)._onNavigation(window.document);
  },

  onStateChange(aWebProgress, aRequest, aState, aStatus) {
    const window = aWebProgress.DOMWindow;
    const loginManagerChild = () => LoginManagerChild.forWindow(window);

    if (
      aState & Ci.nsIWebProgressListener.STATE_RESTORING &&
      aState & Ci.nsIWebProgressListener.STATE_STOP
    ) {
      // Re-fill a document restored from bfcache since password field values
      // aren't persisted there.
      loginManagerChild()._onDocumentRestored(window.document);
      return;
    }

    if (!(aState & Ci.nsIWebProgressListener.STATE_START)) {
      return;
    }

    // We only care about when a page triggered a load, not the user. For example:
    // clicking refresh/back/forward, typing a URL and hitting enter, and loading a bookmark aren't
    // likely to be when a user wants to save a login.
    let channel = aRequest.QueryInterface(Ci.nsIChannel);
    let triggeringPrincipal = channel.loadInfo.triggeringPrincipal;
    if (
      triggeringPrincipal.isNullPrincipal ||
      triggeringPrincipal.equals(
        Services.scriptSecurityManager.getSystemPrincipal()
      )
    ) {
      return;
    }

    // Don't handle history navigation, reload, or pushState not triggered via chrome UI.
    // e.g. history.go(-1), location.reload(), history.replaceState()
    if (!(aWebProgress.loadType & Ci.nsIDocShell.LOAD_CMD_NORMAL)) {
      lazy.log(`loadType isn't LOAD_CMD_NORMAL: ${aWebProgress.loadType}.`);
      return;
    }

    lazy.log(`Handled channel: ${channel}`);
    loginManagerChild()._onNavigation(window.document);
  },

  // nsIObserver
  observe(subject, topic, data) {
    switch (topic) {
      case "autocomplete-did-enter-text": {
        let input = subject.QueryInterface(Ci.nsIAutoCompleteInput);
        let { selectedIndex } = input.popup;
        if (selectedIndex < 0 || selectedIndex >= input.controller.matchCount) {
          break;
        }

        let { focusedInput } = lazy.gFormFillService;
        if (focusedInput.nodePrincipal.isNullPrincipal) {
          // If we have a null principal then prevent any more password manager code from running and
          // incorrectly using the document `location`.
          return;
        }

        let window = focusedInput.ownerGlobal;
        let loginManagerChild = LoginManagerChild.forWindow(window);

        let style = input.controller.getStyleAt(selectedIndex);
        if (style == "login" || style == "loginWithOrigin") {
          let details = JSON.parse(
            input.controller.getCommentAt(selectedIndex)
          );
          loginManagerChild.onFieldAutoComplete(focusedInput, details.guid);
        } else if (style == "generatedPassword") {
          loginManagerChild._filledWithGeneratedPassword(focusedInput);
        }
        break;
      }
    }
  },

  // nsIDOMEventListener
  handleEvent(aEvent) {
    if (!aEvent.isTrusted) {
      return;
    }

    if (!lazy.LoginHelper.enabled) {
      return;
    }

    const ownerDocument = aEvent.target.ownerDocument;
    const window = ownerDocument.defaultView;
    const loginManagerChild = LoginManagerChild.forWindow(window);
    const docState = loginManagerChild.stateForDocument(ownerDocument);
    const field = aEvent.composedTarget;

    switch (aEvent.type) {
      // Used to mask fields with filled generated passwords when blurred.
      case "blur":
        this.handleBlur(docState, field);
        break;

      // Used to watch for changes to username and password fields.
      case "change":
        this.handleChange(docState, field, loginManagerChild);
        break;

      case "input":
        this.handleInput(
          aEvent,
          docState,
          field,
          loginManagerChild,
          ownerDocument
        );
        break;

      case "keydown":
        this.handleKeydown(aEvent, field, loginManagerChild, ownerDocument);
        break;

      case "focus":
        this.handleFocus(field, docState, aEvent.target);
        break;

      case "mousedown":
        this.handleMousedown(aEvent.button);
        break;

      default: {
        throw new Error("Unexpected event");
      }
    }
  },

  handleBlur(docState, field) {
    if (docState.generatedPasswordFields.has(field)) {
      docState._togglePasswordFieldMasking(field, false);
    }
  },

  handleChange(docState, field, loginManagerChild) {
    let formLikeRoot = lazy.FormLikeFactory.findRootForField(field);
    if (!docState.fieldModificationsByRootElement.get(formLikeRoot)) {
      lazy.log("Ignoring change event on form that hasn't been user-modified.");
      if (field.hasBeenTypePassword) {
        // Send notification that the password field has not been changed.
        // This is used only for testing.
        loginManagerChild._ignorePasswordEdit();
      }
      return;
    }

    docState.storeUserInput(field);
    let detail = {
      possibleValues: {
        usernames: docState.possibleUsernames,
        passwords: docState.possiblePasswords,
      },
    };
    loginManagerChild.sendAsyncMessage(
      "PasswordManager:updateDoorhangerSuggestions",
      detail
    );

    if (field.hasBeenTypePassword) {
      let triggeredByFillingGenerated =
        docState.generatedPasswordFields.has(field);
      // Autosave generated password initial fills and subsequent edits
      if (triggeredByFillingGenerated) {
        loginManagerChild._passwordEditedOrGenerated(field, {
          triggeredByFillingGenerated,
        });
      } else {
        // Send a notification that we are not saving the edit to the password field.
        // This is used only for testing.
        loginManagerChild._ignorePasswordEdit();
      }
    }
  },

  handleInput(aEvent, docState, field, loginManagerChild, ownerDocument) {
    let isPasswordType = lazy.LoginHelper.isPasswordFieldType(field);
    // React to input into fields filled with generated passwords.
    if (
      docState.generatedPasswordFields.has(field) &&
      // Depending on the edit, we may no longer want to consider
      // the field a generated password field to avoid autosaving.
      loginManagerChild._doesEventClearPrevFieldValue(aEvent)
    ) {
      docState._stopTreatingAsGeneratedPasswordField(field);
    }

    if (!isPasswordType && !lazy.LoginHelper.isUsernameFieldType(field)) {
      return;
    }

    // React to input into potential username or password fields
    let formLikeRoot = lazy.FormLikeFactory.findRootForField(field);

    if (formLikeRoot !== aEvent.currentTarget) {
      return;
    }
    // flag this form as user-modified for the closest form/root ancestor
    let alreadyModified =
      docState.fieldModificationsByRootElement.get(formLikeRoot);
    let { login: filledLogin, userTriggered: fillWasUserTriggered } =
      docState.fillsByRootElement.get(formLikeRoot) || {};

    // don't flag as user-modified if the form was autofilled and doesn't appear to have changed
    let isAutofillInput = filledLogin && !fillWasUserTriggered;
    if (!alreadyModified && isAutofillInput) {
      if (isPasswordType && filledLogin.password == field.value) {
        lazy.log(
          "Ignoring password input event that doesn't change autofilled values."
        );
        return;
      }
      if (
        !isPasswordType &&
        filledLogin.usernameField &&
        filledLogin.username == field.value
      ) {
        lazy.log(
          "Ignoring username input event that doesn't change autofilled values."
        );
        return;
      }
    }
    docState.fieldModificationsByRootElement.set(formLikeRoot, true);
    // Keep track of the modified formless password field to trigger form submission
    // when it is removed from DOM.
    let alreadyModifiedFormLessField = true;
    if (!HTMLFormElement.isInstance(formLikeRoot)) {
      alreadyModifiedFormLessField =
        docState.formlessModifiedPasswordFields.has(field);
      if (!alreadyModifiedFormLessField) {
        docState.formlessModifiedPasswordFields.add(field);
      }
    }

    // Infer form submission only when there has been an user interaction on the form
    // or the formless password field.
    if (
      lazy.LoginHelper.formRemovalCaptureEnabled &&
      (!alreadyModified || !alreadyModifiedFormLessField)
    ) {
      loginManagerChild.registerDOMDocFetchSuccessEventListener(ownerDocument);
    }

    if (
      // When the password field value is cleared or entirely replaced we don't treat it as
      // an autofilled form any more. We don't do the same for username edits to avoid snooping
      // on the autofilled password in the resulting doorhanger
      isPasswordType &&
      loginManagerChild._doesEventClearPrevFieldValue(aEvent) &&
      // Don't clear last recorded autofill if THIS is an autofilled value. This will be true
      // when filling from the context menu.
      filledLogin &&
      filledLogin.password !== field.value
    ) {
      docState.fillsByRootElement.delete(formLikeRoot);
    }

    if (!lazy.LoginHelper.passwordEditCaptureEnabled) {
      return;
    }
    if (field.hasBeenTypePassword) {
      // When a field is filled with a generated password, we also fill a confirm password field
      // if found. To do this, _fillConfirmFieldWithGeneratedPassword calls setUserInput, which fires
      // an "input" event on the confirm password field. compareAndUpdatePreviouslySentValues will
      // allow that message through due to triggeredByFillingGenerated, so early return here.
      let form = lazy.LoginFormFactory.createFromField(field);
      if (
        docState.generatedPasswordFields.has(field) &&
        docState._getFormFields(form).confirmPasswordField === field
      ) {
        return;
      }
      // Don't check for triggeredByFillingGenerated, as we do not want to autosave
      // a field marked as a generated password field on every "input" event
      loginManagerChild._passwordEditedOrGenerated(field);
    } else {
      let [usernameField, passwordField] =
        docState.getUserNameAndPasswordFields(field);
      if (field == usernameField && passwordField?.value) {
        loginManagerChild._passwordEditedOrGenerated(passwordField, {
          triggeredByFillingGenerated:
            docState.generatedPasswordFields.has(passwordField),
        });
      }
    }
  },

  handleKeydown(aEvent, field, loginManagerChild, ownerDocument) {
    if (
      field.value &&
      (aEvent.keyCode == aEvent.DOM_VK_TAB ||
        aEvent.keyCode == aEvent.DOM_VK_RETURN)
    ) {
      const autofillForm =
        lazy.LoginHelper.autofillForms &&
        !PrivateBrowsingUtils.isContentWindowPrivate(ownerDocument.defaultView);

      if (autofillForm) {
        loginManagerChild.onUsernameAutocompleted(field);
      }
    }
  },

  handleFocus(field, docState, target) {
    //@sg see if we can drop focusedField (aEvent.target) and use field (aEvent.composedTarget)
    docState.onFocus(field, target);
  },

  handleMousedown(button) {
    if (button == 2) {
      // Date.now() is used instead of event.timeStamp since
      // dom.event.highrestimestamp.enabled isn't true on all channels yet.
      gLastRightClickTimeStamp = Date.now();
    }
  },
};

// Add this observer once for the process.
Services.obs.addObserver(observer, "autocomplete-did-enter-text");

/**
 * Form scenario defines what can be done with form.
 */
class FormScenario {}

/**
 * Sign up scenario defines typical account registration flow.
 */
class SignUpFormScenario extends FormScenario {
  usernameField;
  passwordField;
}

/**
 * Logic of Capture and Filling.
 *
 * This class will be shared with Firefox iOS and should have no references to
 * Gecko internals. See Bug 1774208.
 */
export class LoginFormState {
  /**
   * Keeps track of filled fields and values.
   */
  fillsByRootElement = new WeakMap();
  /**
   * Keeps track of fields we've filled with generated passwords
   */
  generatedPasswordFields = new WeakFieldSet();
  /**
   * Keeps track of logins that were last submitted.
   */
  lastSubmittedValuesByRootElement = new WeakMap();
  fieldModificationsByRootElement = new WeakMap();
  /**
   * Anything entered into an <input> that we think might be a username
   */
  possibleUsernames = new Set();
  /**
   * Anything entered into an <input> that we think might be a password
   */
  possiblePasswords = new Set();

  /**
   * Keeps track of the formLike of nodes (form or formless password field)
   * that we are watching when they are removed from DOM.
   */
  formLikeByObservedNode = new WeakMap();

  /**
   * Keeps track of all formless password fields that have been
   * updated by the user.
   */
  formlessModifiedPasswordFields = new WeakFieldSet();

  /**
   * Caches the results of the username heuristics
   */
  #cachedIsInferredUsernameField = new WeakMap();
  #cachedIsInferredEmailField = new WeakMap();
  #cachedIsInferredLoginForm = new WeakMap();

  /**
   * Records the mock username field when its associated form is submitted.
   */
  mockUsernameOnlyField = null;

  /**
   * Records the number of possible username event received for this document.
   */
  numFormHasPossibleUsernameEvent = 0;

  captureLoginTimeStamp = 0;

  // Scenarios detected on this page
  #scenariosByRoot = new WeakMap();

  getScenario(inputElement) {
    const formLikeRoot = lazy.FormLikeFactory.findRootForField(inputElement);
    return this.#scenariosByRoot.get(formLikeRoot);
  }

  setScenario(formLikeRoot, scenario) {
    this.#scenariosByRoot.set(formLikeRoot, scenario);
  }

  storeUserInput(field) {
    if (field.value && lazy.LoginHelper.captureInputChanges) {
      if (lazy.LoginHelper.isPasswordFieldType(field)) {
        this.possiblePasswords.add(field.value);
      } else if (lazy.LoginHelper.isUsernameFieldType(field)) {
        this.possibleUsernames.add(field.value);
      }
    }
  }

  /**
   * Returns true if the input field is considered an email field by
   * 'LoginHelper.isInferredEmailField'.
   *
   * @param {Element} element the field to check.
   * @returns {boolean} True if the element is likely an email field
   */
  isProbablyAnEmailField(inputElement) {
    if (!inputElement) {
      return false;
    }

    let result = this.#cachedIsInferredEmailField.get(inputElement);
    if (result === undefined) {
      result = lazy.LoginHelper.isInferredEmailField(inputElement);
      this.#cachedIsInferredEmailField.set(inputElement, result);
    }

    return result;
  }

  /**
   * Returns true if the input field is considered a username field by
   * 'LoginHelper.isInferredUsernameField'. The main purpose of this method
   * is to cache the result because _getFormFields has many call sites and we
   * want to avoid applying the heuristic every time.
   *
   * @param {Element} element the field to check.
   * @returns {boolean} True if the element is likely a username field
   */
  isProbablyAUsernameField(inputElement) {
    let result = this.#cachedIsInferredUsernameField.get(inputElement);
    if (result === undefined) {
      result = lazy.LoginHelper.isInferredUsernameField(inputElement);
      this.#cachedIsInferredUsernameField.set(inputElement, result);
    }

    return result;
  }

  /**
   * Returns true if the form is considered a username login form if
   * 1. The input element looks like a username field or the form looks
   *    like a login form
   * 2. The input field doesn't match keywords that indicate the username
   *    is not used for login (ex, search) or the login form is not use
   *    a username to sign-in (ex, authentication code)
   *
   * @param {Element} element the form to check.
   * @returns {boolean} True if the element is likely a login form
   */
  #isProbablyAUsernameLoginForm(formElement, inputElement) {
    let result = this.#cachedIsInferredLoginForm.get(formElement);
    if (result === undefined) {
      // We should revisit these rules after we collect more positive or negative
      // cases for username-only forms. Right now, if-else-based rules are good
      // enough to cover the sites we know, but if we find out defining "weight" for each
      // rule is necessary to improve the heuristic, we should consider switching
      // this with Fathom.

      result = false;
      // Check whether the input field looks like a username field or the
      // form looks like a sign-in or sign-up form.
      if (
        this.isProbablyAUsernameField(inputElement) ||
        lazy.LoginHelper.isInferredLoginForm(formElement)
      ) {
        // This is where we collect hints that indicate this is not a username
        // login form.
        if (!lazy.LoginHelper.isInferredNonUsernameField(inputElement)) {
          result = true;
        }
      }
      this.#cachedIsInferredLoginForm.set(formElement, result);
    }

    return result;
  }

  /**
   * Given a field, determine whether that field was last filled as a username
   * field AND whether the username is still filled in with the username AND
   * whether the associated password field has the matching password.
   *
   * @note This could possibly be unified with getFieldContext but they have
   * slightly different use cases. getFieldContext looks up recipes whereas this
   * method doesn't need to since it's only returning a boolean based upon the
   * recipes used for the last fill (in _fillForm).
   *
   * @param {HTMLInputElement} aUsernameField element contained in a LoginForm
   *                                          cached in LoginFormFactory.
   * @returns {Boolean} whether the username and password fields still have the
   *                    last-filled values, if previously filled.
   */
  #isLoginAlreadyFilled(aUsernameField) {
    let formLikeRoot = lazy.FormLikeFactory.findRootForField(aUsernameField);
    // Look for the existing LoginForm.
    let existingLoginForm =
      lazy.LoginFormFactory.getForRootElement(formLikeRoot);
    if (!existingLoginForm) {
      throw new Error(
        "#isLoginAlreadyFilled called with a username field with " +
          "no rootElement LoginForm"
      );
    }

    let { login: filledLogin } =
      this.fillsByRootElement.get(formLikeRoot) || {};
    if (!filledLogin) {
      return false;
    }

    // Unpack the weak references.
    let autoFilledUsernameField = filledLogin.usernameField?.get();
    let autoFilledPasswordField = filledLogin.passwordField?.get();

    // Check username and password values match what was filled.
    if (
      !autoFilledUsernameField ||
      autoFilledUsernameField != aUsernameField ||
      autoFilledUsernameField.value != filledLogin.username ||
      (autoFilledPasswordField &&
        autoFilledPasswordField.value != filledLogin.password)
    ) {
      return false;
    }

    return true;
  }

  _togglePasswordFieldMasking(passwordField, unmask) {
    let { editor } = passwordField;

    if (passwordField.type != "password") {
      // The type may have been changed by the website.
      lazy.log("Field isn't type=password.");
      return;
    }

    if (!unmask && !editor) {
      // It hasn't been created yet but the default is to be masked anyways.
      return;
    }

    if (unmask) {
      editor.unmask(0);
      return;
    }

    if (editor.autoMaskingEnabled) {
      return;
    }
    editor.mask();
  }

  /**
   * Track a form field as has having been filled with a generated password. This adds explicit
   * focus & blur handling to unmask & mask the value, and enables special handling of edits to
   * generated password values (see the observer's input event handler.)
   *
   * @param {HTMLInputElement} passwordField
   */
  _treatAsGeneratedPasswordField(passwordField) {
    this.generatedPasswordFields.add(passwordField);

    // blur/focus: listen for focus changes to we can mask/unmask generated passwords
    for (let eventType of ["blur", "focus"]) {
      passwordField.addEventListener(eventType, observer, {
        capture: true,
        mozSystemGroup: true,
      });
    }
    if (passwordField.ownerDocument.activeElement == passwordField) {
      // Unmask the password field
      this._togglePasswordFieldMasking(passwordField, true);
    }
  }

  _formHasModifiedFields(form) {
    const doc = form.rootElement.ownerDocument;
    let userHasInteracted;
    const testOnlyUserHasInteracted =
      lazy.LoginHelper.testOnlyUserHasInteractedWithDocument;
    if (Cu.isInAutomation && testOnlyUserHasInteracted !== null) {
      userHasInteracted = testOnlyUserHasInteracted;
    } else {
      userHasInteracted =
        !lazy.LoginHelper.userInputRequiredToCapture ||
        this.captureLoginTimeStamp != doc.lastUserGestureTimeStamp;
    }

    lazy.log(
      `_formHasModifiedFields: userHasInteracted: ${userHasInteracted}.`
    );

    // Skip if user didn't interact with the page since last call or ever
    if (!userHasInteracted) {
      return false;
    }

    // check for user inputs to the form fields
    let fieldsModified = this.fieldModificationsByRootElement.get(
      form.rootElement
    );
    // also consider a form modified if there's a difference between fields' .value and .defaultValue
    if (!fieldsModified) {
      fieldsModified = Array.from(form.elements).some(
        field =>
          field.defaultValue !== undefined && field.value !== field.defaultValue
      );
    }
    return fieldsModified;
  }

  _stopTreatingAsGeneratedPasswordField(passwordField) {
    this.generatedPasswordFields.delete(passwordField);

    // Remove all the event listeners added in _passwordEditedOrGenerated
    for (let eventType of ["blur", "focus"]) {
      passwordField.removeEventListener(eventType, observer, {
        capture: true,
        mozSystemGroup: true,
      });
    }

    // Mask the password field
    this._togglePasswordFieldMasking(passwordField, false);
  }

  onFocus(field, focusedField) {
    if (field.hasBeenTypePassword && this.generatedPasswordFields.has(field)) {
      // Used to unmask fields with filled generated passwords when focused.
      this._togglePasswordFieldMasking(field, true);
      return;
    }

    // Only used for username fields.
    this.#onUsernameFocus(focusedField);
  }

  /**
   * Focus event handler for username fields to decide whether to show autocomplete.
   * @param {HTMLInputElement} focusedField
   */
  #onUsernameFocus(focusedField) {
    if (
      !focusedField.mozIsTextField(true) ||
      focusedField.hasBeenTypePassword ||
      focusedField.readOnly
    ) {
      return;
    }

    if (this.#isLoginAlreadyFilled(focusedField)) {
      lazy.log("Login already filled.");
      return;
    }

    /*
     * A `mousedown` event is fired before the `focus` event if the user right clicks into an
     * unfocused field. In that case we don't want to show both autocomplete and a context menu
     * overlapping so we check against the timestamp that was set by the `mousedown` event if the
     * button code indicated a right click.
     * We use a timestamp instead of a bool to avoid complexity when dealing with multiple input
     * forms and the fact that a mousedown into an already focused field does not trigger another focus.
     * Date.now() is used instead of event.timeStamp since dom.event.highrestimestamp.enabled isn't
     * true on all channels yet.
     */
    let timeDiff = Date.now() - gLastRightClickTimeStamp;
    if (timeDiff < AUTOCOMPLETE_AFTER_RIGHT_CLICK_THRESHOLD_MS) {
      lazy.log(
        `Not opening autocomplete after focus since a context menu was opened within ${timeDiff}ms.`
      );
      return;
    }

    // The login manager is responsible for fields with the "webauthn" credential type.
    let acCredentialType = focusedField.getAutocompleteInfo()?.credentialType;
    if (acCredentialType == "webauthn") {
      lazy.gFormFillService.markAsLoginManagerField(focusedField);
    }

    lazy.log("Opening the autocomplete popup.");
    lazy.gFormFillService.showPopup();
  }

  /** Remove login field highlight when its value is cleared or overwritten.
   */
  static #removeFillFieldHighlight(event) {
    let winUtils = event.target.ownerGlobal.windowUtils;
    winUtils.removeManuallyManagedState(event.target, AUTOFILL_STATE);
  }

  /**
   * Highlight login fields on autocomplete or autofill on page load.
   * @param {Node} element that needs highlighting.
   */
  static _highlightFilledField(element) {
    let winUtils = element.ownerGlobal.windowUtils;

    winUtils.addManuallyManagedState(element, AUTOFILL_STATE);
    // Remove highlighting when the field is changed.
    element.addEventListener(
      "input",
      LoginFormState.#removeFillFieldHighlight,
      {
        mozSystemGroup: true,
        once: true,
      }
    );
  }

  /**
   * Returns the username field of the passed form if the form is a
   * username-only form.
   * A form is considered a username-only form only if it meets all the
   * following conditions:
   * 1. Does not have any password field,
   * 2. Only contains one input field whose type is username compatible.
   * 3. The username compatible input field looks like a username field
   *    or the form itself looks like a sign-in or sign-up form.
   *
   * @param {Element} formElement
   *                  the form to check.
   * @param {Object}  recipe=null
   *                  A relevant field override recipe to use.
   * @returns {Element} The username field or null (if the form is not a
   *                    username-only form).
   */
  getUsernameFieldFromUsernameOnlyForm(formElement, recipe = null) {
    if (!HTMLFormElement.isInstance(formElement)) {
      return null;
    }

    let candidate = null;
    for (let element of formElement.elements) {
      // We are looking for a username-only form, so if there is a password
      // field in the form, this is NOT a username-only form.
      if (element.hasBeenTypePassword) {
        return null;
      }

      // Ignore input fields whose type are not username compatiable, ex, hidden.
      if (!lazy.LoginHelper.isUsernameFieldType(element)) {
        continue;
      }

      if (
        recipe?.notUsernameSelector &&
        element.matches(recipe.notUsernameSelector)
      ) {
        continue;
      }

      // If there are more than two input fields whose type is username
      // compatiable, this is NOT a username-only form.
      if (candidate) {
        return null;
      }
      candidate = element;
    }

    if (
      candidate &&
      this.#isProbablyAUsernameLoginForm(formElement, candidate)
    ) {
      return candidate;
    }

    return null;
  }

  /**
   * @param {LoginForm} form - the LoginForm to look for password fields in.
   * @param {Object} options
   * @param {bool} [options.skipEmptyFields=false] - Whether to ignore password fields with no value.
   *                                                 Used at capture time since saving empty values isn't
   *                                                 useful.
   * @param {Object} [options.fieldOverrideRecipe=null] - A relevant field override recipe to use.
   * @return {Array|null} Array of password field elements for the specified form.
   *                      If no pw fields are found, or if more than 5 are found, then null
   *                      is returned.
   */
  static _getPasswordFields(
    form,
    {
      fieldOverrideRecipe = null,
      minPasswordLength = 0,
      ignoreConnect = false,
    } = {}
  ) {
    // Locate the password fields in the form.
    let pwFields = [];
    for (let i = 0; i < form.elements.length; i++) {
      let element = form.elements[i];
      if (
        !HTMLInputElement.isInstance(element) ||
        !element.hasBeenTypePassword ||
        (!element.isConnected && !ignoreConnect)
      ) {
        continue;
      }

      // Exclude ones matching a `notPasswordSelector`, if specified.
      if (
        fieldOverrideRecipe?.notPasswordSelector &&
        element.matches(fieldOverrideRecipe.notPasswordSelector)
      ) {
        lazy.log(
          `Skipping password field with id: ${element.id}, name: ${element.name} due to recipe ${fieldOverrideRecipe}.`
        );
        continue;
      }

      // XXX: Bug 780449 tracks our handling of emoji and multi-code-point characters in
      // password fields. To avoid surprises, we should be consistent with the visual
      // representation of the masked password
      if (
        minPasswordLength &&
        element.value.trim().length < minPasswordLength
      ) {
        lazy.log(
          `Skipping password field with id: ${element.id}, name: ${element.name} as value is too short.`
        );
        continue; // Ignore empty or too-short passwords fields
      }

      pwFields[pwFields.length] = {
        index: i,
        element,
      };
    }

    // If too few or too many fields, bail out.
    if (!pwFields.length) {
      lazy.log("Form ignored, no password fields.");
      return null;
    }

    if (pwFields.length > 5) {
      lazy.log(`Form ignored, too many password fields:  ${pwFields.length}.`);
      return null;
    }

    return pwFields;
  }

  /**
   * Stores passed arguments, and returns whether or not they match the args given the last time
   * this method was called with the same [formLikeRoot]. This is used to avoid sending duplicate
   * messages to the parent.
   *
   * @param {Element} formLikeRoot
   * @param {string} usernameValue
   * @param {string} passwordValue
   * @param {boolean?} [dismissed=false]
   * @param {boolean?} [triggeredByFillingGenerated=false] whether or not this call was triggered by a generated
   *        password being filled into a form-like element.
   *
   * @returns {boolean} true if args match the most recently passed values
   */
  compareAndUpdatePreviouslySentValues(
    formLikeRoot,
    usernameValue,
    passwordValue,
    dismissed = false,
    triggeredByFillingGenerated = false
  ) {
    const lastSentValues =
      this.lastSubmittedValuesByRootElement.get(formLikeRoot);
    if (lastSentValues) {
      if (dismissed && !lastSentValues.dismissed) {
        // preserve previous dismissed value if it was false (i.e. shown/open)
        dismissed = false;
      }
      if (
        lastSentValues.username == usernameValue &&
        lastSentValues.password == passwordValue &&
        lastSentValues.dismissed == dismissed &&
        lastSentValues.triggeredByFillingGenerated ==
          triggeredByFillingGenerated
      ) {
        lazy.log(
          "compareAndUpdatePreviouslySentValues: values are equivalent, returning true."
        );
        return true;
      }
    }

    // Save the last submitted values so we don't prompt twice for the same values using
    // different capture methods e.g. a form submit event and upon navigation.
    this.lastSubmittedValuesByRootElement.set(formLikeRoot, {
      username: usernameValue,
      password: passwordValue,
      dismissed,
      triggeredByFillingGenerated,
    });
    lazy.log(
      "compareAndUpdatePreviouslySentValues: values not equivalent, returning false."
    );
    return false;
  }

  fillConfirmFieldWithGeneratedPassword(passwordField) {
    // Fill a nearby password input if it looks like a confirm-password field
    let form = lazy.LoginFormFactory.createFromField(passwordField);
    let confirmPasswordInput = null;
    // The confirm-password field shouldn't be more than 3 form elements away from the password field we filled
    let MAX_CONFIRM_PASSWORD_DISTANCE = 3;

    let startIndex = form.elements.indexOf(passwordField);
    if (startIndex == -1) {
      throw new Error(
        "Password field is not in the form's elements collection"
      );
    }

    // If we've already filled another field with a generated password,
    // this might be the confirm-password field, so don't try and find another
    let previousGeneratedPasswordField = form.elements.some(
      inp => inp !== passwordField && this.generatedPasswordFields.has(inp)
    );
    if (previousGeneratedPasswordField) {
      lazy.log("Previously-filled generated password input found.");
      return;
    }

    // Get a list of input fields to search in.
    // Pre-filter type=hidden fields; they don't count against the distance threshold
    let afterFields = form.elements
      .slice(startIndex + 1)
      .filter(elem => elem.type !== "hidden");

    let acFieldName = passwordField.getAutocompleteInfo()?.fieldName;

    // Match same autocomplete values first
    if (acFieldName == "new-password") {
      let matchIndex = afterFields.findIndex(
        elem =>
          lazy.LoginHelper.isPasswordFieldType(elem) &&
          elem.getAutocompleteInfo().fieldName == acFieldName &&
          !elem.disabled &&
          !elem.readOnly
      );
      if (matchIndex >= 0 && matchIndex < MAX_CONFIRM_PASSWORD_DISTANCE) {
        confirmPasswordInput = afterFields[matchIndex];
      }
    }
    if (!confirmPasswordInput) {
      for (
        let idx = 0;
        idx < Math.min(MAX_CONFIRM_PASSWORD_DISTANCE, afterFields.length);
        idx++
      ) {
        if (
          lazy.LoginHelper.isPasswordFieldType(afterFields[idx]) &&
          !afterFields[idx].disabled &&
          !afterFields[idx].readOnly
        ) {
          confirmPasswordInput = afterFields[idx];
          break;
        }
      }
    }
    if (confirmPasswordInput && !confirmPasswordInput.value) {
      this._treatAsGeneratedPasswordField(confirmPasswordInput);
      confirmPasswordInput.setUserInput(passwordField.value);
      LoginFormState._highlightFilledField(confirmPasswordInput);
    }
  }

  /**
   * Returns the username and password fields found in the form.
   * Can handle complex forms by trying to figure out what the
   * relevant fields are.
   *
   * @param {LoginForm} form
   * @param {bool} isSubmission
   * @param {Set} recipes
   * @param {Object} options
   * @param {bool} [options.ignoreConnect] - Whether to ignore checking isConnected
   *                                         of the element.
   * @return {Object} {usernameField, newPasswordField, oldPasswordField, confirmPasswordField}
   *
   * usernameField may be null.
   * newPasswordField may be null. If null, this is a username-only form.
   * oldPasswordField may be null. If null, newPasswordField is just
   * "theLoginField". If not null, the form is apparently a
   * change-password field, with oldPasswordField containing the password
   * that is being changed.
   *
   * Note that even though we can create a LoginForm from a text field,
   * this method will only return a non-null usernameField if the
   * LoginForm has a password field.
   */
  _getFormFields(form, isSubmission, recipes, { ignoreConnect = false } = {}) {
    let usernameField = null;
    let newPasswordField = null;
    let oldPasswordField = null;
    let confirmPasswordField = null;
    let emptyResult = {
      usernameField: null,
      newPasswordField: null,
      oldPasswordField: null,
      confirmPasswordField: null,
    };

    let pwFields = null;
    let fieldOverrideRecipe = lazy.LoginRecipesContent.getFieldOverrides(
      recipes,
      form
    );
    if (fieldOverrideRecipe) {
      lazy.log("fieldOverrideRecipe found ", fieldOverrideRecipe);
      let pwOverrideField = lazy.LoginRecipesContent.queryLoginField(
        form,
        fieldOverrideRecipe.passwordSelector
      );
      if (pwOverrideField) {
        lazy.log("pwOverrideField found ", pwOverrideField);
        // The field from the password override may be in a different LoginForm.
        let formLike = lazy.LoginFormFactory.createFromField(pwOverrideField);
        pwFields = [
          {
            index: [...formLike.elements].indexOf(pwOverrideField),
            element: pwOverrideField,
          },
        ];
      }

      let usernameOverrideField = lazy.LoginRecipesContent.queryLoginField(
        form,
        fieldOverrideRecipe.usernameSelector
      );
      if (usernameOverrideField) {
        usernameField = usernameOverrideField;
      }
    }

    if (!pwFields) {
      // Locate the password field(s) in the form. Up to 5 supported.
      // If there's no password field, there's nothing for us to do.
      const minSubmitPasswordLength = 2;
      pwFields = LoginFormState._getPasswordFields(form, {
        fieldOverrideRecipe,
        minPasswordLength: isSubmission ? minSubmitPasswordLength : 0,
        ignoreConnect,
      });
    }

    // Check whether this is a username-only form when the form doesn't have
    // a password field. Note that recipes are not supported in username-only
    // forms currently (Bug 1708455).
    if (!pwFields) {
      if (!lazy.LoginHelper.usernameOnlyFormEnabled) {
        return emptyResult;
      }

      usernameField = this.getUsernameFieldFromUsernameOnlyForm(
        form.rootElement,
        fieldOverrideRecipe
      );

      if (usernameField) {
        lazy.log(`Found username field with name: ${usernameField.name}.`);
      }

      return {
        ...emptyResult,
        usernameField,
      };
    }

    if (!usernameField) {
      // Searching backwards from the first password field until we find a field
      // that looks like a "username" field. If no "username" field is found,
      // consider an email-like field a username field, if any.
      // If neither a username-like or an email-like field exists, assume the
      // first text field before the password field is the username.
      // We might not find a username field if the user is already logged in to the site.
      //
      // Note: We only search fields precede the first password field because we
      // don't see sites putting a username field after a password field. We can
      // extend searching to all fields in the form if this turns out not to be the case.

      for (let i = pwFields[0].index - 1; i >= 0; i--) {
        let element = form.elements[i];
        if (!lazy.LoginHelper.isUsernameFieldType(element, { ignoreConnect })) {
          continue;
        }

        if (
          fieldOverrideRecipe?.notUsernameSelector &&
          element.matches(fieldOverrideRecipe.notUsernameSelector)
        ) {
          continue;
        }

        // Assume the first text field is the username by default.
        // It will be replaced if we find a likely username field afterward.
        if (!usernameField) {
          usernameField = element;
        }

        if (this.isProbablyAUsernameField(element)) {
          // An username field is found, we are done.
          usernameField = element;
          break;
        } else if (this.isProbablyAnEmailField(element)) {
          // An email field is found, consider it a username field but continue
          // to search for an "username" field.
          // In current implementation, if another email field is found during
          // the process, we will use the new one.
          usernameField = element;
        }
      }
    }

    if (!usernameField) {
      lazy.log("No username field found.");
    } else {
      lazy.log(`Found username field with name: ${usernameField.name}.`);
    }

    let pwGeneratedFields = pwFields.filter(pwField =>
      this.generatedPasswordFields.has(pwField.element)
    );
    if (pwGeneratedFields.length) {
      // we have at least the newPasswordField
      [newPasswordField, confirmPasswordField] = pwGeneratedFields.map(
        pwField => pwField.element
      );
      // if the user filled a field with a generated password,
      // a field immediately previous to that is most likely the old password field
      let idx = pwFields.findIndex(
        pwField => pwField.element === newPasswordField
      );
      if (idx > 0) {
        oldPasswordField = pwFields[idx - 1].element;
      }
      return {
        ...emptyResult,
        usernameField,
        newPasswordField,
        oldPasswordField: oldPasswordField || null,
        confirmPasswordField: confirmPasswordField || null,
      };
    }

    // If we're not submitting a form (it's a page load), there are no
    // password field values for us to use for identifying fields. So,
    // just assume the first password field is the one to be filled in.
    if (!isSubmission || pwFields.length == 1) {
      let passwordField = pwFields[0].element;
      lazy.log(`Found Password field with name: ${passwordField.name}.`);
      return {
        ...emptyResult,
        usernameField,
        newPasswordField: passwordField,
        oldPasswordField: null,
      };
    }

    // We're looking for both new and old password field
    // Try to figure out what is in the form based on the password values.
    let pw1 = pwFields[0].element.value;
    let pw2 = pwFields[1] ? pwFields[1].element.value : null;
    let pw3 = pwFields[2] ? pwFields[2].element.value : null;

    if (pwFields.length == 3) {
      // Look for two identical passwords, that's the new password

      if (pw1 == pw2 && pw2 == pw3) {
        // All 3 passwords the same? Weird! Treat as if 1 pw field.
        newPasswordField = pwFields[0].element;
        oldPasswordField = null;
      } else if (pw1 == pw2) {
        newPasswordField = pwFields[0].element;
        oldPasswordField = pwFields[2].element;
      } else if (pw2 == pw3) {
        oldPasswordField = pwFields[0].element;
        newPasswordField = pwFields[2].element;
      } else if (pw1 == pw3) {
        // A bit odd, but could make sense with the right page layout.
        newPasswordField = pwFields[0].element;
        oldPasswordField = pwFields[1].element;
      } else {
        // We can't tell which of the 3 passwords should be saved.
        lazy.log(`Form ignored -- all 3 pw fields differ.`);
        return emptyResult;
      }
    } else if (pw1 == pw2) {
      // pwFields.length == 2
      // Treat as if 1 pw field
      newPasswordField = pwFields[0].element;
      oldPasswordField = null;
    } else {
      // Just assume that the 2nd password is the new password
      oldPasswordField = pwFields[0].element;
      newPasswordField = pwFields[1].element;
    }

    lazy.log(
      `New Password field id: ${newPasswordField.id}, name: ${newPasswordField.name}.`
    );

    lazy.log(
      oldPasswordField
        ? `Old Password field id: ${oldPasswordField.id}, name: ${oldPasswordField.name}.`
        : "No Old password field."
    );
    return {
      ...emptyResult,
      usernameField,
      newPasswordField,
      oldPasswordField,
    };
  }

  /**
   * Returns the username and password fields found in the form by input
   * element into form.
   *
   * @param {HTMLInputElement} aField
   *                           A form field
   * @return {Array} [usernameField, newPasswordField, oldPasswordField]
   *
   * Details of these values are the same as _getFormFields.
   */
  getUserNameAndPasswordFields(aField) {
    const noResult = [null, null, null];
    if (!HTMLInputElement.isInstance(aField)) {
      throw new Error("getUserNameAndPasswordFields: input element required");
    }

    if (aField.nodePrincipal.isNullPrincipal || !aField.isConnected) {
      return noResult;
    }

    // If the element is not a login form field, return all null.
    if (
      !aField.hasBeenTypePassword &&
      !lazy.LoginHelper.isUsernameFieldType(aField)
    ) {
      return noResult;
    }

    const form = lazy.LoginFormFactory.createFromField(aField);
    const doc = aField.ownerDocument;
    const formOrigin = lazy.LoginHelper.getLoginOrigin(doc.documentURI);
    const recipes = lazy.LoginRecipesContent.getRecipes(
      formOrigin,
      doc.defaultView
    );
    const { usernameField, newPasswordField, oldPasswordField } =
      this._getFormFields(form, false, recipes);

    return [usernameField, newPasswordField, oldPasswordField];
  }

  /**
   * Verify if a field is a valid login form field and
   * returns some information about it's LoginForm.
   *
   * @param {Element} aField
   *                  A form field we want to verify.
   *
   * @returns {Object} an object with information about the
   *                   LoginForm username and password field
   *                   or null if the passed field is invalid.
   */
  getFieldContext(aField) {
    // If the element is not a proper form field, return null.
    if (
      !HTMLInputElement.isInstance(aField) ||
      (!aField.hasBeenTypePassword &&
        !lazy.LoginHelper.isUsernameFieldType(aField)) ||
      aField.nodePrincipal.isNullPrincipal ||
      aField.nodePrincipal.schemeIs("about") ||
      !aField.ownerDocument
    ) {
      return null;
    }
    let { hasBeenTypePassword } = aField;

    // This array provides labels that correspond to the return values from
    // `getUserNameAndPasswordFields` so we can know which one aField is.
    const LOGIN_FIELD_ORDER = ["username", "new-password", "current-password"];
    let usernameAndPasswordFields = this.getUserNameAndPasswordFields(aField);
    let fieldNameHint;
    let indexOfFieldInUsernameAndPasswordFields =
      usernameAndPasswordFields.indexOf(aField);
    if (indexOfFieldInUsernameAndPasswordFields == -1) {
      // For fields in the form that are neither username nor password,
      // set fieldNameHint to "other". Right now, in contextmenu, we treat both
      // "username" and "other" field as username fields.
      fieldNameHint = hasBeenTypePassword ? "current-password" : "other";
    } else {
      fieldNameHint =
        LOGIN_FIELD_ORDER[indexOfFieldInUsernameAndPasswordFields];
    }
    let [, newPasswordField] = usernameAndPasswordFields;

    return {
      activeField: {
        disabled: aField.disabled || aField.readOnly,
        fieldNameHint,
      },
      // `passwordField` may be the same as `activeField`.
      passwordField: {
        found: !!newPasswordField,
        disabled:
          newPasswordField &&
          (newPasswordField.disabled || newPasswordField.readOnly),
      },
    };
  }
}

/**
 * Integration with browser and IPC with LoginManagerParent.
 *
 * NOTE: there are still bits of code here that needs to be moved to
 * LoginFormState.
 */
export class LoginManagerChild extends JSWindowActorChild {
  /**
   * WeakMap of the root element of a LoginForm to the DeferredTask to fill its fields.
   *
   * This is used to be able to throttle fills for a LoginForm since onDOMInputPasswordAdded gets
   * dispatched for each password field added to a document but we only want to fill once per
   * LoginForm when multiple fields are added at once.
   *
   * @type {WeakMap}
   */
  #deferredPasswordAddedTasksByRootElement = new WeakMap();

  /**
   * WeakMap of a document to the array of callbacks to execute when it becomes visible
   *
   * This is used to defer handling DOMFormHasPassword and onDOMInputPasswordAdded events when the
   * containing document is hidden.
   * When the document first becomes visible, any queued events will be handled as normal.
   *
   * @type {WeakMap}
   */
  #visibleTasksByDocument = new WeakMap();

  /**
   * Maps all DOM content documents in this content process, including those in
   * frames, to the current state used by the Login Manager.
   */
  #loginFormStateByDocument = new WeakMap();

  /**
   * Set of fields where the user specifically requested password generation
   * (from the context menu) even if we wouldn't offer it on this field by default.
   */
  #fieldsWithPasswordGenerationForcedOn = new WeakSet();

  static forWindow(window) {
    return window.windowGlobalChild?.getActor("LoginManager");
  }

  receiveMessage(msg) {
    switch (msg.name) {
      case "PasswordManager:fillForm": {
        this.fillForm({
          loginFormOrigin: msg.data.loginFormOrigin,
          loginsFound: lazy.LoginHelper.vanillaObjectsToLogins(msg.data.logins),
          recipes: msg.data.recipes,
          inputElementIdentifier: msg.data.inputElementIdentifier,
          originMatches: msg.data.originMatches,
          style: msg.data.style,
        });
        break;
      }
      case "PasswordManager:useGeneratedPassword": {
        this.#onUseGeneratedPassword(msg.data.inputElementIdentifier);
        break;
      }
      case "PasswordManager:repopulateAutocompletePopup": {
        this.repopulateAutocompletePopup();
        break;
      }
      case "PasswordManager:formIsPending": {
        return this.#visibleTasksByDocument.has(this.document);
      }
      case "PasswordManager:formProcessed": {
        this.notifyObserversOfFormProcessed(msg.data.formid);
        break;
      }
    }

    return undefined;
  }

  #onUseGeneratedPassword(inputElementIdentifier) {
    let inputElement = lazy.ContentDOMReference.resolve(inputElementIdentifier);
    if (!inputElement) {
      lazy.log("Could not resolve inputElementIdentifier to a living element.");
      return;
    }

    if (inputElement != lazy.gFormFillService.focusedInput) {
      lazy.log("Could not open popup on input that's no longer focused.");
      return;
    }

    this.#fieldsWithPasswordGenerationForcedOn.add(inputElement);
    this.repopulateAutocompletePopup();
  }

  repopulateAutocompletePopup() {
    // Clear the cache of previous autocomplete results to show new options.
    lazy.gFormFillService.QueryInterface(Ci.nsIAutoCompleteInput);
    lazy.gFormFillService.controller.resetInternalState();
    lazy.gFormFillService.showPopup();
  }

  shouldIgnoreLoginManagerEvent(event) {
    let nodePrincipal = event.target.nodePrincipal;
    // If we have a system or null principal then prevent any more password manager code from running and
    // incorrectly using the document `location`. Also skip password manager for about: pages.
    return (
      nodePrincipal.isSystemPrincipal ||
      nodePrincipal.isNullPrincipal ||
      nodePrincipal.schemeIs("about")
    );
  }

  registerDOMDocFetchSuccessEventListener(document) {
    document.setNotifyFetchSuccess(true);
    this.docShell.chromeEventHandler.addEventListener(
      "DOMDocFetchSuccess",
      this,
      true
    );
  }

  unregisterDOMDocFetchSuccessEventListener(document) {
    document.setNotifyFetchSuccess(false);
    this.docShell.chromeEventHandler.removeEventListener(
      "DOMDocFetchSuccess",
      this
    );
  }

  handleEvent(event) {
    if (
      AppConstants.platform == "android" &&
      Services.prefs.getBoolPref("reftest.remote", false)
    ) {
      // XXX known incompatibility between reftest harness and form-fill. Is this still needed?
      return;
    }

    if (this.shouldIgnoreLoginManagerEvent(event)) {
      return;
    }

    switch (event.type) {
      case "DOMDocFetchSuccess": {
        this.#onDOMDocFetchSuccess(event);
        break;
      }
      case "DOMFormBeforeSubmit": {
        this.#onDOMFormBeforeSubmit(event);
        break;
      }
      case "DOMFormHasPassword": {
        this.#onDOMFormHasPassword(event, this.document.defaultView);
        let formLike = lazy.LoginFormFactory.createFromForm(
          event.originalTarget
        );
        lazy.InsecurePasswordUtils.reportInsecurePasswords(formLike);
        break;
      }
      case "DOMFormHasPossibleUsername": {
        this.#onDOMFormHasPossibleUsername(event);
        break;
      }
      case "DOMFormRemoved":
      case "DOMInputPasswordRemoved": {
        this.#onDOMFormRemoved(event);
        break;
      }
      case "DOMInputPasswordAdded": {
        this.#onDOMInputPasswordAdded(event, this.document.defaultView);
        let formLike = lazy.LoginFormFactory.createFromField(
          event.originalTarget
        );
        lazy.InsecurePasswordUtils.reportInsecurePasswords(formLike);
        break;
      }
    }
  }

  notifyObserversOfFormProcessed(formid) {
    Services.obs.notifyObservers(this, "passwordmgr-processed-form", formid);
  }

  /**
   * Get relevant logins and recipes from the parent
   *
   * @param {HTMLFormElement} form - form to get login data for
   * @param {Object} options
   * @param {boolean} options.guid - guid of a login to retrieve
   * @param {boolean} options.showPrimaryPassword - whether to show a primary password prompt
   */
  _getLoginDataFromParent(form, options) {
    let actionOrigin = lazy.LoginHelper.getFormActionOrigin(form);
    let messageData = { actionOrigin, options };
    let resultPromise = this.sendQuery(
      "PasswordManager:findLogins",
      messageData
    );
    return resultPromise.then(result => {
      return {
        form,
        importable: result.importable,
        loginsFound: lazy.LoginHelper.vanillaObjectsToLogins(result.logins),
        recipes: result.recipes,
      };
    });
  }

  setupProgressListener(window) {
    if (!lazy.LoginHelper.formlessCaptureEnabled) {
      return;
    }

    // Get the highest accessible docshell and attach the progress listener to that.
    let docShell;
    for (
      let browsingContext = BrowsingContext.getFromWindow(window);
      browsingContext?.docShell;
      browsingContext = browsingContext.parent
    ) {
      docShell = browsingContext.docShell;
    }

    try {
      let webProgress = docShell
        .QueryInterface(Ci.nsIInterfaceRequestor)
        .getInterface(Ci.nsIWebProgress);
      webProgress.addProgressListener(
        observer,
        Ci.nsIWebProgress.NOTIFY_STATE_DOCUMENT |
          Ci.nsIWebProgress.NOTIFY_LOCATION
      );
    } catch (ex) {
      // Ignore NS_ERROR_FAILURE if the progress listener was already added
    }
  }

  /**
   * This method sets up form removal listener for form and password fields that
   * users have interacted with.
   */
  #onDOMDocFetchSuccess(event) {
    let document = event.target;
    let docState = this.stateForDocument(document);
    let weakModificationsRootElements =
      ChromeUtils.nondeterministicGetWeakMapKeys(
        docState.fieldModificationsByRootElement
      );

    lazy.log(
      `modificationsByRootElement approx size: ${weakModificationsRootElements.length}.`
    );
    // Start to listen to form/password removed event after receiving a fetch/xhr
    // complete event.
    document.setNotifyFormOrPasswordRemoved(true);
    this.docShell.chromeEventHandler.addEventListener(
      "DOMFormRemoved",
      this,
      true
    );
    this.docShell.chromeEventHandler.addEventListener(
      "DOMInputPasswordRemoved",
      this,
      true
    );

    for (let rootElement of weakModificationsRootElements) {
      if (HTMLFormElement.isInstance(rootElement)) {
        // If we create formLike when it is removed, we might not have the
        // right elements at that point, so create formLike object now.
        let formLike = lazy.LoginFormFactory.createFromForm(rootElement);
        docState.formLikeByObservedNode.set(rootElement, formLike);
      }
    }

    let weakFormlessModifiedPasswordFields =
      ChromeUtils.nondeterministicGetWeakSetKeys(
        docState.formlessModifiedPasswordFields
      );

    lazy.log(
      `formlessModifiedPasswordFields approx size: ${weakFormlessModifiedPasswordFields.length}.`
    );
    for (let passwordField of weakFormlessModifiedPasswordFields) {
      let formLike = lazy.LoginFormFactory.createFromField(passwordField);
      // force elements lazy getter being called.
      if (formLike.elements.length) {
        docState.formLikeByObservedNode.set(passwordField, formLike);
      }
    }

    // Observers have been set up, remove the listener.
    this.unregisterDOMDocFetchSuccessEventListener(document);
  }

  /*
   * Trigger capture when a form/formless password is removed from DOM.
   * This method is used to capture logins for cases where form submit events
   * are not used.
   *
   * The heuristic works as follow:
   * 1. Set up 'DOMDocFetchSuccess' event listener when users have interacted
   *    with a form (by calling setNotifyFetchSuccess)
   * 2. After receiving `DOMDocFetchSuccess`, set up form removal event listener
   *    (see onDOMDocFetchSuccess)
   * 3. When a form is removed, onDOMFormRemoved triggers the login capture
   *    code.
   */
  #onDOMFormRemoved(event) {
    let document = event.composedTarget.ownerDocument;
    let docState = this.stateForDocument(document);
    let formLike = docState.formLikeByObservedNode.get(event.target);
    if (!formLike) {
      return;
    }

    lazy.log("Form is removed.");
    this._onFormSubmit(formLike, SUBMIT_FORM_IS_REMOVED);

    docState.formLikeByObservedNode.delete(event.target);
    let weakObserveredNodes = ChromeUtils.nondeterministicGetWeakMapKeys(
      docState.formLikeByObservedNode
    );

    if (!weakObserveredNodes.length) {
      document.setNotifyFormOrPasswordRemoved(false);
      this.docShell.chromeEventHandler.removeEventListener(
        "DOMFormRemoved",
        this
      );
      this.docShell.chromeEventHandler.removeEventListener(
        "DOMInputPasswordRemoved",
        this
      );
    }
  }

  #onDOMFormBeforeSubmit(event) {
    if (!event.isTrusted) {
      return;
    }

    // We're invoked before the content's |submit| event handlers, so we
    // can grab form data before it might be modified (see bug 257781).
    let formLike = lazy.LoginFormFactory.createFromForm(event.target);
    this._onFormSubmit(formLike, SUBMIT_FORM_SUBMIT);
  }

  onDocumentVisibilityChange(event) {
    if (!event.isTrusted) {
      return;
    }
    let document = event.target;
    let onVisibleTasks = this.#visibleTasksByDocument.get(document);
    if (!onVisibleTasks) {
      return;
    }
    for (let task of onVisibleTasks) {
      lazy.log("onDocumentVisibilityChange: executing queued task.");
      task();
    }
    this.#visibleTasksByDocument.delete(document);
  }

  _deferHandlingEventUntilDocumentVisible(event, document, fn) {
    lazy.log(
      `Defer handling event, document.visibilityState: ${document.visibilityState}, defer handling ${event.type}.`
    );
    let onVisibleTasks = this.#visibleTasksByDocument.get(document);
    if (!onVisibleTasks) {
      lazy.log(
        "Defer handling first queued event and register the visibilitychange handler."
      );
      onVisibleTasks = [];
      this.#visibleTasksByDocument.set(document, onVisibleTasks);
      document.addEventListener(
        "visibilitychange",
        event => {
          this.onDocumentVisibilityChange(event);
        },
        { once: true }
      );
    }
    onVisibleTasks.push(fn);
  }

  #getIsPrimaryPasswordSet() {
    return Services.cpmm.sharedData.get("isPrimaryPasswordSet");
  }

  #onDOMFormHasPassword(event, window) {
    if (!event.isTrusted) {
      return;
    }

    this.setupProgressListener(window);

    const isPrimaryPasswordSet = this.#getIsPrimaryPasswordSet();
    let document = event.target.ownerDocument;

    // don't attempt to defer handling when a primary password is set
    // Showing the MP modal as soon as possible minimizes its interference with tab interactions
    // See bug 1539091 and bug 1538460.
    lazy.log(
      `#onDOMFormHasPassword: visibilityState: ${document.visibilityState}, isPrimaryPasswordSet: ${isPrimaryPasswordSet}.`
    );

    if (document.visibilityState == "visible" || isPrimaryPasswordSet) {
      this._processDOMFormHasPasswordEvent(event);
    } else {
      // wait until the document becomes visible before handling this event
      this._deferHandlingEventUntilDocumentVisible(event, document, () => {
        this._processDOMFormHasPasswordEvent(event);
      });
    }
  }

  _processDOMFormHasPasswordEvent(event) {
    let form = event.target;
    let formLike = lazy.LoginFormFactory.createFromForm(form);
    this._fetchLoginsFromParentAndFillForm(formLike);
  }

  #onDOMFormHasPossibleUsername(event) {
    if (!event.isTrusted) {
      return;
    }
    const isPrimaryPasswordSet = this.#getIsPrimaryPasswordSet();
    let document = event.target.ownerDocument;

    lazy.log(
      `#onDOMFormHasPossibleUsername: visibilityState: ${document.visibilityState}, isPrimaryPasswordSet: ${isPrimaryPasswordSet}.`
    );

    // For simplicity, the result of the telemetry is stacked. This means if a
    // document receives two `DOMFormHasPossibleEvent`, we add one counter to both
    // bucket 1 & 2.
    let docState = this.stateForDocument(document);
    Services.telemetry
      .getHistogramById("PWMGR_NUM_FORM_HAS_POSSIBLE_USERNAME_EVENT_PER_DOC")
      .add(++docState.numFormHasPossibleUsernameEvent);

    // Infer whether a form is a username-only form is expensive, so we restrict the
    // number of form looked up per document.
    if (
      docState.numFormHasPossibleUsernameEvent >
      lazy.LoginHelper.usernameOnlyFormLookupThreshold
    ) {
      return;
    }

    if (document.visibilityState == "visible" || isPrimaryPasswordSet) {
      this._processDOMFormHasPossibleUsernameEvent(event);
    } else {
      // wait until the document becomes visible before handling this event
      this._deferHandlingEventUntilDocumentVisible(event, document, () => {
        this._processDOMFormHasPossibleUsernameEvent(event);
      });
    }
  }

  _processDOMFormHasPossibleUsernameEvent(event) {
    let form = event.target;
    let formLike = lazy.LoginFormFactory.createFromForm(form);

    // If the form contains a passoword field, `getUsernameFieldFromUsernameOnlyForm` returns
    // null, so we don't trigger autofill for those forms here. In this function,
    // we only care about username-only forms. For forms contain a password, they'll be handled
    // in onDOMFormHasPassword.

    // We specifically set the recipe to empty here to avoid loading site recipes during page loads.
    // This is okay because if we end up finding a username-only form that should be ignore by
    // the site recipe, the form will be skipped while autofilling later.
    let docState = this.stateForDocument(form.ownerDocument);
    let usernameField = docState.getUsernameFieldFromUsernameOnlyForm(form, {});
    if (usernameField) {
      // Autofill the username-only form.
      lazy.log("A username-only form is found.");
      this._fetchLoginsFromParentAndFillForm(formLike);
    }

    Services.telemetry
      .getHistogramById("PWMGR_IS_USERNAME_ONLY_FORM")
      .add(!!usernameField);
  }

  #onDOMInputPasswordAdded(event, window) {
    if (!event.isTrusted) {
      return;
    }

    this.setupProgressListener(window);

    let pwField = event.originalTarget;
    if (pwField.form) {
      // Fill is handled by onDOMFormHasPassword which is already throttled.
      return;
    }

    let document = pwField.ownerDocument;
    const isPrimaryPasswordSet = this.#getIsPrimaryPasswordSet();
    lazy.log(
      `#onDOMInputPasswordAdded, visibilityState: ${document.visibilityState}, isPrimaryPasswordSet: ${isPrimaryPasswordSet}.`
    );

    // don't attempt to defer handling when a primary password is set
    // Showing the MP modal as soon as possible minimizes its interference with tab interactions
    // See bug 1539091 and bug 1538460.
    if (document.visibilityState == "visible" || isPrimaryPasswordSet) {
      this._processDOMInputPasswordAddedEvent(event);
    } else {
      // wait until the document becomes visible before handling this event
      this._deferHandlingEventUntilDocumentVisible(event, document, () => {
        this._processDOMInputPasswordAddedEvent(event);
      });
    }
  }

  _processDOMInputPasswordAddedEvent(event) {
    let pwField = event.originalTarget;
    let formLike = lazy.LoginFormFactory.createFromField(pwField);

    let deferredTask = this.#deferredPasswordAddedTasksByRootElement.get(
      formLike.rootElement
    );
    if (!deferredTask) {
      lazy.log(
        "Creating a DeferredTask to call _fetchLoginsFromParentAndFillForm soon."
      );
      lazy.LoginFormFactory.setForRootElement(formLike.rootElement, formLike);

      deferredTask = new lazy.DeferredTask(
        () => {
          // Get the updated LoginForm instead of the one at the time of creating the DeferredTask via
          // a closure since it could be stale since LoginForm.elements isn't live.
          let formLike2 = lazy.LoginFormFactory.getForRootElement(
            formLike.rootElement
          );
          lazy.log("Running deferred processing of onDOMInputPasswordAdded.");
          this.#deferredPasswordAddedTasksByRootElement.delete(
            formLike2.rootElement
          );
          this._fetchLoginsFromParentAndFillForm(formLike2);
        },
        PASSWORD_INPUT_ADDED_COALESCING_THRESHOLD_MS,
        0
      );

      this.#deferredPasswordAddedTasksByRootElement.set(
        formLike.rootElement,
        deferredTask
      );
    }

    let window = pwField.ownerGlobal;
    if (deferredTask.isArmed) {
      lazy.log("DeferredTask is already armed so just updating the LoginForm.");
      // We update the LoginForm so it (most important .elements) is fresh when the task eventually
      // runs since changes to the elements could affect our field heuristics.
      lazy.LoginFormFactory.setForRootElement(formLike.rootElement, formLike);
    } else if (
      ["interactive", "complete"].includes(window.document.readyState)
    ) {
      lazy.log(
        "Arming the DeferredTask we just created since document.readyState == 'interactive' or 'complete'."
      );
      deferredTask.arm();
    } else {
      window.addEventListener(
        "DOMContentLoaded",
        function () {
          lazy.log(
            "Arming the onDOMInputPasswordAdded DeferredTask due to DOMContentLoaded."
          );
          deferredTask.arm();
        },
        { once: true }
      );
    }
  }

  /**
   * Fetch logins from the parent for a given form and then attempt to fill it.
   *
   * @param {LoginForm} form to fetch the logins for then try autofill.
   */
  _fetchLoginsFromParentAndFillForm(form) {
    if (!lazy.LoginHelper.enabled) {
      return;
    }

    // set up input event listeners so we know if the user has interacted with these fields
    // * input: Listen for the field getting blanked (without blurring) or a paste
    // * change: Listen for changes to the field filled with the generated password so we can preserve edits.
    form.rootElement.addEventListener("input", observer, {
      capture: true,
      mozSystemGroup: true,
    });
    form.rootElement.addEventListener("change", observer, {
      capture: true,
      mozSystemGroup: true,
    });

    this._getLoginDataFromParent(form, { showPrimaryPassword: true })
      .then(this.loginsFound.bind(this))
      .catch(console.error);
  }

  isPasswordGenerationForcedOn(passwordField) {
    return this.#fieldsWithPasswordGenerationForcedOn.has(passwordField);
  }

  /**
   * Retrieves a reference to the state object associated with the given
   * document. This is initialized to an object with default values.
   */
  stateForDocument(document) {
    let loginFormState = this.#loginFormStateByDocument.get(document);
    if (!loginFormState) {
      loginFormState = new LoginFormState();
      this.#loginFormStateByDocument.set(document, loginFormState);
    }
    return loginFormState;
  }

  /**
   * Perform a password fill upon user request coming from the parent process.
   * The fill will be in the form previously identified during page navigation.
   *
   * @param An object with the following properties:
   *        {
   *          loginFormOrigin:
   *            String with the origin for which the login UI was displayed.
   *            This must match the origin of the form used for the fill.
   *          loginsFound:
   *            Array containing the login to fill. While other messages may
   *            have more logins, for this use case this is expected to have
   *            exactly one element. The origin of the login may be different
   *            from the origin of the form used for the fill.
   *          recipes:
   *            Fill recipes transmitted together with the original message.
   *          inputElementIdentifier:
   *            An identifier generated for the input element via ContentDOMReference.
   *          originMatches:
   *            True if the origin of the form matches the page URI.
   *        }
   */
  fillForm({
    loginFormOrigin,
    loginsFound,
    recipes,
    inputElementIdentifier,
    originMatches,
    style,
  }) {
    if (!inputElementIdentifier) {
      lazy.log("No input element specified.");
      return;
    }

    let inputElement = lazy.ContentDOMReference.resolve(inputElementIdentifier);
    if (!inputElement) {
      lazy.log("Could not resolve inputElementIdentifier to a living element.");
      return;
    }

    if (!originMatches) {
      if (
        lazy.LoginHelper.getLoginOrigin(
          inputElement.ownerDocument.documentURI
        ) != loginFormOrigin
      ) {
        lazy.log(
          "The requested origin doesn't match the one from the",
          "document. This may mean we navigated to a document from a different",
          "site before we had a chance to indicate this change in the user",
          "interface."
        );
        return;
      }
    }

    let clobberUsername = true;
    let form = lazy.LoginFormFactory.createFromField(inputElement);
    if (inputElement.hasBeenTypePassword) {
      clobberUsername = false;
    }

    this._fillForm(form, loginsFound, recipes, {
      inputElement,
      autofillForm: true,
      clobberUsername,
      clobberPassword: true,
      userTriggered: true,
      style,
    });
  }

  loginsFound({ form, importable, loginsFound, recipes }) {
    let doc = form.ownerDocument;
    let autofillForm =
      lazy.LoginHelper.autofillForms &&
      !PrivateBrowsingUtils.isContentWindowPrivate(doc.defaultView);

    let formOrigin = lazy.LoginHelper.getLoginOrigin(doc.documentURI);
    lazy.LoginRecipesContent.cacheRecipes(formOrigin, doc.defaultView, recipes);

    this._fillForm(form, loginsFound, recipes, { autofillForm, importable });
  }

  /**
   * A username or password was autocompleted into a field.
   */
  onFieldAutoComplete(acInputField, loginGUID) {
    if (!lazy.LoginHelper.enabled) {
      return;
    }

    // This is probably a bit over-conservatative.
    if (!Document.isInstance(acInputField.ownerDocument)) {
      return;
    }

    if (!lazy.LoginFormFactory.createFromField(acInputField)) {
      return;
    }

    if (lazy.LoginHelper.isUsernameFieldType(acInputField)) {
      this.onUsernameAutocompleted(acInputField, loginGUID);
    } else if (acInputField.hasBeenTypePassword) {
      // Ensure the field gets re-masked and edits don't overwrite the generated
      // password in case a generated password was filled into it previously.
      const docState = this.stateForDocument(acInputField.ownerDocument);
      docState._stopTreatingAsGeneratedPasswordField(acInputField);
      LoginFormState._highlightFilledField(acInputField);
    }
  }

  /**
   * A username field was filled or tabbed away from so try fill in the
   * associated password in the password field.
   */
  onUsernameAutocompleted(acInputField, loginGUID = null) {
    lazy.log(`Autocompleting input field with name: ${acInputField.name}`);

    let acForm = lazy.LoginFormFactory.createFromField(acInputField);
    let doc = acForm.ownerDocument;
    let formOrigin = lazy.LoginHelper.getLoginOrigin(doc.documentURI);
    let recipes = lazy.LoginRecipesContent.getRecipes(
      formOrigin,
      doc.defaultView
    );

    // Make sure the username field fillForm will use is the
    // same field as the autocomplete was activated on.
    const docState = this.stateForDocument(acInputField.ownerDocument);
    let { usernameField, newPasswordField: passwordField } =
      docState._getFormFields(acForm, false, recipes);
    if (usernameField == acInputField) {
      // Fill the form when a password field is present.
      if (passwordField) {
        this._getLoginDataFromParent(acForm, {
          guid: loginGUID,
          showPrimaryPassword: false,
        })
          .then(({ form, loginsFound, recipes }) => {
            if (!loginGUID) {
              // not an explicit autocomplete menu selection, filter for exact matches only
              loginsFound = this._filterForExactFormOriginLogins(
                loginsFound,
                acForm
              );
              // filter the list for exact matches with the username
              // NOTE: this could be an empty string which is a valid username
              let searchString = usernameField.value.toLowerCase();
              loginsFound = loginsFound.filter(
                l => l.username.toLowerCase() == searchString
              );
            }

            this._fillForm(form, loginsFound, recipes, {
              autofillForm: true,
              clobberPassword: true,
              userTriggered: true,
            });
          })
          .catch(console.error);
        // Use `loginGUID !== null` to distinguish whether this is called when the
        // field is filled or tabbed away from. For the latter, don't highlight the field.
      } else if (loginGUID !== null) {
        LoginFormState._highlightFilledField(usernameField);
      }
    } else {
      // Ignore the event, it's for some input we don't care about.
    }
  }

  /**
   * @return true if the page requests autocomplete be disabled for the
   *              specified element.
   */
  _isAutocompleteDisabled(element) {
    return element?.autocomplete == "off";
  }

  /**
   * Fill a page that was restored from bfcache since we wouldn't receive
   * DOMInputPasswordAdded or DOMFormHasPassword events for it.
   * @param {Document} aDocument that was restored from bfcache.
   */
  _onDocumentRestored(aDocument) {
    let rootElsWeakSet =
      lazy.LoginFormFactory.getRootElementsWeakSetForDocument(aDocument);
    let weakLoginFormRootElements =
      ChromeUtils.nondeterministicGetWeakSetKeys(rootElsWeakSet);

    lazy.log(
      `loginFormRootElements approx size: ${weakLoginFormRootElements.length}.`
    );

    for (let formRoot of weakLoginFormRootElements) {
      if (!formRoot.isConnected) {
        continue;
      }

      let formLike = lazy.LoginFormFactory.getForRootElement(formRoot);
      this._fetchLoginsFromParentAndFillForm(formLike);
    }
  }

  /**
   * Trigger capture on any relevant FormLikes due to a navigation alone (not
   * necessarily due to an actual form submission). This method is used to
   * capture logins for cases where form submit events are not used.
   *
   * To avoid multiple notifications for the same LoginForm, this currently
   * avoids capturing when dealing with a real <form> which are ideally already
   * using a submit event.
   *
   * @param {Document} document being navigated
   */
  _onNavigation(aDocument) {
    let rootElsWeakSet =
      lazy.LoginFormFactory.getRootElementsWeakSetForDocument(aDocument);
    let weakLoginFormRootElements =
      ChromeUtils.nondeterministicGetWeakSetKeys(rootElsWeakSet);

    lazy.log(`root elements approx size: ${weakLoginFormRootElements.length}`);

    for (let formRoot of weakLoginFormRootElements) {
      if (!formRoot.isConnected) {
        continue;
      }

      let formLike = lazy.LoginFormFactory.getForRootElement(formRoot);
      this._onFormSubmit(formLike, SUBMIT_PAGE_NAVIGATION);
    }
  }

  /**
   * Called by our observer when notified of a form submission.
   * [Note that this happens before any DOM onsubmit handlers are invoked.]
   * Looks for a password change in the submitted form, so we can update
   * our stored password.
   *
   * @param {LoginForm} form
   */
  _onFormSubmit(form, reason) {
    lazy.log("Detected form submission.");

    this._maybeSendFormInteractionMessage(
      form,
      "PasswordManager:ShowDoorhanger",
      {
        targetField: null,
        isSubmission: true,
        // When this is trigger by inferring from form removal, the form is not
        // connected anymore, skip checking isConnected in this case.
        ignoreConnect: reason == SUBMIT_FORM_IS_REMOVED,
      }
    );
  }

  /**
   * Extracts and validates information from a form-like element on the page.  If validation is
   * successful, sends a message to the parent process requesting that it show a dialog.
   *
   * The validation works are divided into two parts:
   * 1. Whether this is a valid form with a password (validate in this function)
   * 2. Whether the password manager decides to send interaction message for this form
   *    (validate in _maybeSendFormInteractionMessageContinue)
   *
   * When the function is triggered by a form submission event, and the form is valid (pass #1),
   * We still send the message to the parent even the validation of #2 fails. This is because
   * there might be someone who is interested in form submission events regardless of whether
   * the password manager decides to show the doorhanger or not.
   *
   * @param {LoginForm} form
   * @param {string} messageName used to categorize the type of message sent to the parent process.
   * @param {Element?} options.targetField
   * @param {boolean} options.isSubmission if true, this function call was prompted by a form submission.
   * @param {boolean?} options.triggeredByFillingGenerated whether or not this call was triggered by a
   *        generated password being filled into a form-like element.
   * @param {boolean?} options.ignoreConnect Whether to ignore isConnected attribute of a element.
   *
   * @returns {Boolean} whether the message is sent to the parent process.
   */
  _maybeSendFormInteractionMessage(
    form,
    messageName,
    { targetField, isSubmission, triggeredByFillingGenerated, ignoreConnect }
  ) {
    let logMessagePrefix = isSubmission
      ? LOG_MESSAGE_FORM_SUBMISSION
      : LOG_MESSAGE_FIELD_EDIT;
    let doc = form.ownerDocument;
    let win = doc.defaultView;
    let passwordField = null;
    if (targetField?.hasBeenTypePassword) {
      passwordField = targetField;
    }

    let origin = lazy.LoginHelper.getLoginOrigin(doc.documentURI);
    if (!origin) {
      lazy.log(`${logMessagePrefix} ignored -- invalid origin.`);
      return;
    }

    // Get the appropriate fields from the form.
    let recipes = lazy.LoginRecipesContent.getRecipes(origin, win);
    const docState = this.stateForDocument(form.ownerDocument);
    let fields = {
      targetField,
      ...docState._getFormFields(form, true, recipes, { ignoreConnect }),
    };

    if (fields.usernameField) {
      lazy.gFormFillService.markAsLoginManagerField(fields.usernameField);
    }

    // It's possible the field triggering this message isn't one of those found by _getFormFields' heuristics
    if (
      passwordField &&
      passwordField != fields.newPasswordField &&
      passwordField != fields.oldPasswordField &&
      passwordField != fields.confirmPasswordField
    ) {
      fields.newPasswordField = passwordField;
    }

    // Need at least 1 valid password field to do anything.
    if (fields.newPasswordField == null) {
      if (isSubmission && fields.usernameField) {
        lazy.log(
          "_onFormSubmit: username-only form. Record the username field but not sending prompt."
        );
        docState.mockUsernameOnlyField = {
          name: fields.usernameField.name,
          value: fields.usernameField.value,
        };
      }
      return;
    }

    this._maybeSendFormInteractionMessageContinue(form, messageName, {
      ...fields,
      isSubmission,
      triggeredByFillingGenerated,
    });

    if (isSubmission) {
      // Notify `PasswordManager:onFormSubmit` as long as we detect submission event on a
      // valid form with a password field.
      this.sendAsyncMessage(
        "PasswordManager:onFormSubmit",
        {},
        {
          fields,
          isSubmission,
          triggeredByFillingGenerated,
        }
      );
    }
  }

  /**
   * Continues the works that are not done in _maybeSendFormInteractionMessage.
   * See comments in _maybeSendFormInteractionMessage for more details.
   */
  _maybeSendFormInteractionMessageContinue(
    form,
    messageName,
    {
      targetField,
      usernameField,
      newPasswordField,
      oldPasswordField,
      confirmPasswordField,
      isSubmission,
      triggeredByFillingGenerated,
    }
  ) {
    let logMessagePrefix = isSubmission
      ? LOG_MESSAGE_FORM_SUBMISSION
      : LOG_MESSAGE_FIELD_EDIT;
    let doc = form.ownerDocument;
    let win = doc.defaultView;
    let detail = { messageSent: false };
    try {
      // when filling a generated password, we do still want to message the parent
      if (
        !triggeredByFillingGenerated &&
        PrivateBrowsingUtils.isContentWindowPrivate(win) &&
        !lazy.LoginHelper.privateBrowsingCaptureEnabled
      ) {
        // We won't do anything in private browsing mode anyway,
        // so there's no need to perform further checks.
        lazy.log(`${logMessagePrefix} ignored in private browsing mode.`);
        return;
      }

      // If password saving is disabled globally, bail out now.
      if (!lazy.LoginHelper.enabled) {
        return;
      }

      let fullyMungedPattern = /^\*+$|^•+$|^\.+$/;
      // Check `isSubmission` to allow munged passwords in dismissed by default doorhangers (since
      // they are initiated by the user) in case this matches their actual password.
      if (isSubmission && newPasswordField?.value.match(fullyMungedPattern)) {
        lazy.log("New password looks munged. Not sending prompt.");
        return;
      }

      // When the username field is empty, check whether we have found it previously from
      // a username-only form, if yes, fill in its value.
      // XXX This is not ideal, we only use the previous saved username field when the current
      // form doesn't have one. This means if there is a username field found in the current
      // form, we don't compare it to the saved one, which might be a better choice in some cases.
      // The reason we are not doing it now is because we haven't found a real world example.
      let docState = this.stateForDocument(doc);
      if (!usernameField) {
        if (docState.mockUsernameOnlyField) {
          usernameField = docState.mockUsernameOnlyField;
        }
      }
      if (usernameField?.value.match(/\.{3,}|\*{3,}|•{3,}/)) {
        lazy.log(
          `usernameField with name ${usernameField.name} looks munged, setting to null.`
        );
        usernameField = null;
      }

      // Check for autocomplete=off attribute. We don't use it to prevent
      // autofilling (for existing logins), but won't save logins when it's
      // present and the storeWhenAutocompleteOff pref is false.
      // XXX spin out a bug that we don't update timeLastUsed in this case?
      if (
        (this._isAutocompleteDisabled(form) ||
          this._isAutocompleteDisabled(usernameField) ||
          this._isAutocompleteDisabled(newPasswordField) ||
          this._isAutocompleteDisabled(oldPasswordField)) &&
        !lazy.LoginHelper.storeWhenAutocompleteOff
      ) {
        lazy.log(`${logMessagePrefix} ignored -- autocomplete=off found.`);
        return;
      }

      // Don't try to send DOM nodes over IPC.
      let mockUsername = usernameField
        ? { name: usernameField.name, value: usernameField.value }
        : null;
      let mockPassword = {
        name: newPasswordField.name,
        value: newPasswordField.value,
      };
      let mockOldPassword = oldPasswordField
        ? { name: oldPasswordField.name, value: oldPasswordField.value }
        : null;

      let usernameValue = usernameField?.value;
      // Dismiss prompt if the username field is a credit card number AND
      // if the password field is a three digit number. Also dismiss prompt if
      // the password is a credit card number and the password field has attribute
      // autocomplete="cc-number".
      let dismissedPrompt = !isSubmission;
      let newPasswordFieldValue = newPasswordField.value;
      if (
        (!dismissedPrompt &&
          CreditCard.isValidNumber(usernameValue) &&
          newPasswordFieldValue.trim().match(/^[0-9]{3}$/)) ||
        (CreditCard.isValidNumber(newPasswordFieldValue) &&
          newPasswordField.getAutocompleteInfo().fieldName == "cc-number")
      ) {
        dismissedPrompt = true;
      }

      const fieldsModified = docState._formHasModifiedFields(form);
      if (!fieldsModified && lazy.LoginHelper.userInputRequiredToCapture) {
        if (targetField) {
          throw new Error("No user input on targetField");
        }
        // we know no fields in this form had user modifications, so don't prompt
        lazy.log(
          `${logMessagePrefix} ignored -- submitting values that are not changed by the user.`
        );
        return;
      }

      if (
        docState.compareAndUpdatePreviouslySentValues(
          form.rootElement,
          usernameValue,
          newPasswordField.value,
          dismissedPrompt,
          triggeredByFillingGenerated
        )
      ) {
        lazy.log(
          `${logMessagePrefix} ignored -- already submitted with the same username and password.`
        );
        return;
      }

      let { login: autoFilledLogin } =
        docState.fillsByRootElement.get(form.rootElement) || {};
      let browsingContextId = win.windowGlobalChild.browsingContext.id;
      let formActionOrigin = lazy.LoginHelper.getFormActionOrigin(form);

      detail = {
        browsingContextId,
        formActionOrigin,
        autoFilledLoginGuid: autoFilledLogin && autoFilledLogin.guid,
        usernameField: mockUsername,
        newPasswordField: mockPassword,
        oldPasswordField: mockOldPassword,
        dismissedPrompt,
        triggeredByFillingGenerated,
        possibleValues: {
          usernames: docState.possibleUsernames,
          passwords: docState.possiblePasswords,
        },
        messageSent: true,
      };

      if (messageName == "PasswordManager:ShowDoorhanger") {
        docState.captureLoginTimeStamp = doc.lastUserGestureTimeStamp;
      }
      this.sendAsyncMessage(messageName, detail);
    } catch (ex) {
      console.error(ex);
      throw ex;
    } finally {
      detail.form = form;
      const evt = new CustomEvent(messageName, { detail });
      win.windowRoot.dispatchEvent(evt);
    }
  }

  /**
   * Heuristic for whether or not we should consider [field]s value to be 'new' (as opposed to
   * 'changed') after applying [event].
   *
   * @param {HTMLInputElement} event.target input element being changed.
   * @param {string?} event.data new value being input into the field.
   *
   * @returns {boolean}
   */
  _doesEventClearPrevFieldValue({ target, data, inputType }) {
    return (
      !target.value ||
      // We check inputType here as a proxy for the previous field value.
      // If the previous field value was empty, e.g. automatically filling
      // a confirm password field when a new password field is filled with
      // a generated password, there's nothing to replace.
      // We may be able to use the "beforeinput" event instead when that
      // ships (Bug 1609291).
      (data && data == target.value && inputType !== "insertReplacementText")
    );
  }

  /**
   * The password field has been filled with a generated password, ensure the
   * field is handled accordingly.
   * @param {HTMLInputElement} passwordField
   */
  _filledWithGeneratedPassword(passwordField) {
    LoginFormState._highlightFilledField(passwordField);
    this._passwordEditedOrGenerated(passwordField, {
      triggeredByFillingGenerated: true,
    });
    let docState = this.stateForDocument(passwordField.ownerDocument);
    docState.fillConfirmFieldWithGeneratedPassword(passwordField);
  }

  /**
   * Notify the parent that we are ignoring the password edit
   * so that tests can listen for this as opposed to waiting for
   * nothing to happen.
   */
  _ignorePasswordEdit() {
    if (Cu.isInAutomation) {
      this.sendAsyncMessage("PasswordManager:onIgnorePasswordEdit", {});
    }
  }
  /**
   * Notify the parent that a generated password was filled into a field or
   * edited so that it can potentially be saved.
   * @param {HTMLInputElement} passwordField
   */
  _passwordEditedOrGenerated(
    passwordField,
    { triggeredByFillingGenerated = false } = {}
  ) {
    lazy.log(
      `Password field with name ${passwordField.name} was filled or edited.`
    );

    if (!lazy.LoginHelper.enabled && triggeredByFillingGenerated) {
      throw new Error(
        "A generated password was filled while the password manager was disabled."
      );
    }

    let loginForm = lazy.LoginFormFactory.createFromField(passwordField);

    if (triggeredByFillingGenerated) {
      LoginFormState._highlightFilledField(passwordField);
      let docState = this.stateForDocument(passwordField.ownerDocument);
      docState._treatAsGeneratedPasswordField(passwordField);

      // Once the generated password was filled we no longer want to autocomplete
      // saved logins into a non-empty password field (see LoginAutoComplete.startSearch)
      // because it is confusing.
      this.#fieldsWithPasswordGenerationForcedOn.delete(passwordField);
    }

    this._maybeSendFormInteractionMessage(
      loginForm,
      "PasswordManager:onPasswordEditedOrGenerated",
      {
        targetField: passwordField,
        isSubmission: false,
        triggeredByFillingGenerated,
      }
    );
  }

  /**
   * Filter logins for exact origin/formActionOrigin and dedupe on usernamematche
   * @param {nsILoginInfo[]} logins an array of nsILoginInfo that could be
   *        used for the form, including ones with a different form action origin
   *        which are only used when the fill is userTriggered
   * @param {LoginForm} form
   */
  _filterForExactFormOriginLogins(logins, form) {
    let loginOrigin = lazy.LoginHelper.getLoginOrigin(
      form.ownerDocument.documentURI
    );
    let formActionOrigin = lazy.LoginHelper.getFormActionOrigin(form);
    logins = logins.filter(l => {
      let formActionMatches = lazy.LoginHelper.isOriginMatching(
        l.formActionOrigin,
        formActionOrigin,
        {
          schemeUpgrades: lazy.LoginHelper.schemeUpgrades,
          acceptWildcardMatch: true,
          acceptDifferentSubdomains: true,
        }
      );
      let formOriginMatches = lazy.LoginHelper.isOriginMatching(
        l.origin,
        loginOrigin,
        {
          schemeUpgrades: lazy.LoginHelper.schemeUpgrades,
          acceptWildcardMatch: true,
          acceptDifferentSubdomains: false,
        }
      );
      return formActionMatches && formOriginMatches;
    });

    // Since the logins are already filtered now to only match the origin and formAction,
    // dedupe to just the username since remaining logins may have different schemes.
    logins = lazy.LoginHelper.dedupeLogins(
      logins,
      ["username"],
      ["scheme", "timePasswordChanged"],
      loginOrigin,
      formActionOrigin
    );
    return logins;
  }

  /**
   * Attempt to find the username and password fields in a form, and fill them
   * in using the provided logins and recipes.
   *
   * @param {LoginForm} form
   * @param {nsILoginInfo[]} foundLogins an array of nsILoginInfo that could be
   *        used for the form, including ones with a different form action origin
   *        which are only used when the fill is userTriggered
   * @param {Set} recipes a set of recipes that could be used to affect how the
   *        form is filled
   * @param {Object} [options = {}] a list of options for this method
   * @param {HTMLInputElement} [options.inputElement = null] an optional target
   *        input element we want to fill
   * @param {bool} [options.autofillForm = false] denotes if we should fill the
   *        form in automatically
   * @param {bool} [options.clobberUsername = false] controls if an existing
   *        username can be overwritten. If this is false and an inputElement
   *        of type password is also passed, the username field will be ignored.
   *        If this is false and no inputElement is passed, if the username
   *        field value is not found in foundLogins, it will not fill the
   *        password.
   * @param {bool} [options.clobberPassword = false] controls if an existing
   *        password value can be overwritten
   * @param {bool} [options.userTriggered = false] an indication of whether
   *        this filling was triggered by the user
   */
  // eslint-disable-next-line complexity
  _fillForm(
    form,
    foundLogins,
    recipes,
    {
      inputElement = null,
      autofillForm = false,
      importable = null,
      clobberUsername = false,
      clobberPassword = false,
      userTriggered = false,
      style = null,
    } = {}
  ) {
    if (HTMLFormElement.isInstance(form)) {
      throw new Error("_fillForm should only be called with LoginForm objects");
    }

    lazy.log(`Found ${form.elements.length} form elements.`);
    // Will be set to one of AUTOFILL_RESULT in the `try` block.
    let autofillResult;
    const docState = this.stateForDocument(form.ownerDocument);

    // Heuristically determine what the user/pass fields are
    // We do this before checking to see if logins are stored,
    // so that the user isn't prompted for a primary password
    // without need.
    let { usernameField, newPasswordField: passwordField } =
      docState._getFormFields(form, false, recipes);

    const passwordACFieldName = passwordField?.getAutocompleteInfo().fieldName;

    let scenario;

    if (usernameField) {
      const isSignUpForm =
        lazy.FormScenarios.detect({
          input: usernameField,
          formRoot: form.rootElement,
        }).signUpForm ?? passwordACFieldName == "new-password";

      if (isSignUpForm) {
        scenario = new SignUpFormScenario(usernameField, passwordField);
      }

      if (scenario) {
        docState.setScenario(form.rootElement, scenario);
        lazy.gFormFillService.markAsLoginManagerField(usernameField);
      }
    }

    try {
      // Nothing to do if we have no matching (excluding form action
      // checks) logins available, and there isn't a need to show
      // the insecure form warning.
      if (
        !foundLogins.length &&
        !(importable?.state === "import" && importable?.browsers) &&
        lazy.InsecurePasswordUtils.isFormSecure(form)
      ) {
        // We don't log() here since this is a very common case.
        autofillResult = AUTOFILL_RESULT.NO_SAVED_LOGINS;
        return;
      }

      // If we have a password inputElement parameter and it's not
      // the same as the one heuristically found, use the parameter
      // one instead.
      if (inputElement) {
        if (inputElement.hasBeenTypePassword) {
          passwordField = inputElement;
          if (!clobberUsername) {
            usernameField = null;
          }
        } else if (lazy.LoginHelper.isUsernameFieldType(inputElement)) {
          usernameField = inputElement;
        } else {
          throw new Error("Unexpected input element type.");
        }
      }

      // Need a valid password or username field to do anything.
      if (passwordField == null && usernameField == null) {
        lazy.log("Not filling form, no password and username field found.");
        autofillResult = AUTOFILL_RESULT.NO_PASSWORD_FIELD;
        return;
      }

      // Attach autocomplete stuff to the username field, if we have
      // one. This is normally used to select from multiple accounts,
      // but even with one account we should refill if the user edits.
      // We would also need this attached to show the insecure login
      // warning, regardless of saved login.
      if (usernameField) {
        lazy.gFormFillService.markAsLoginManagerField(usernameField);
        usernameField.addEventListener("keydown", observer);
      }

      // If the password field is disabled or read-only, there's nothing to do.
      if (passwordField?.disabled || passwordField?.readOnly) {
        lazy.log("Not filling form, password field disabled or read-only.");
        autofillResult = AUTOFILL_RESULT.PASSWORD_DISABLED_READONLY;
        return;
      }

      if (
        !userTriggered &&
        !form.rootElement.ownerGlobal.windowGlobalChild.sameOriginWithTop
      ) {
        lazy.log("Not filling form; it is in a cross-origin subframe.");
        autofillResult = AUTOFILL_RESULT.FORM_IN_CROSSORIGIN_SUBFRAME;
        return;
      }

      if (!userTriggered) {
        // Only autofill logins that match the form's action and origin. In the above code
        // we have attached autocomplete for logins that don't match the form action.
        foundLogins = this._filterForExactFormOriginLogins(foundLogins, form);
      }

      // Nothing to do if we have no matching logins available.
      // Only insecure pages reach this block and logs the same
      // telemetry flag.
      if (!foundLogins.length) {
        // We don't log() here since this is a very common case.
        autofillResult = AUTOFILL_RESULT.NO_SAVED_LOGINS;
        return;
      }

      // Prevent autofilling insecure forms.
      if (
        !userTriggered &&
        !lazy.LoginHelper.insecureAutofill &&
        !lazy.InsecurePasswordUtils.isFormSecure(form)
      ) {
        lazy.log("Not filling form since it's insecure.");
        autofillResult = AUTOFILL_RESULT.INSECURE;
        return;
      }

      // Discard logins which have username/password values that don't
      // fit into the fields (as specified by the maxlength attribute).
      // The user couldn't enter these values anyway, and it helps
      // with sites that have an extra PIN to be entered (bug 391514)
      let maxUsernameLen = Number.MAX_VALUE;
      let maxPasswordLen = Number.MAX_VALUE;

      // If attribute wasn't set, default is -1.
      if (usernameField?.maxLength >= 0) {
        maxUsernameLen = usernameField.maxLength;
      }
      if (passwordField?.maxLength >= 0) {
        maxPasswordLen = passwordField.maxLength;
      }

      let logins = foundLogins.filter(function (l) {
        let fit =
          l.username.length <= maxUsernameLen &&
          l.password.length <= maxPasswordLen;
        if (!fit) {
          lazy.log(`Ignored login: won't fit ${l.username.length}.`);
        }

        return fit;
      }, this);

      if (!logins.length) {
        lazy.log("Form not filled, none of the logins fit in the field.");
        autofillResult = AUTOFILL_RESULT.NO_LOGINS_FIT;
        return;
      }

      if (passwordField) {
        if (!userTriggered && passwordField.type != "password") {
          // We don't want to autofill (without user interaction) into a field
          // that's unmasked.
          lazy.log(
            "Not autofilling, password field isn't currently type=password."
          );
          autofillResult = AUTOFILL_RESULT.TYPE_NO_LONGER_PASSWORD;
          return;
        }

        // If the password field has the autocomplete value of "new-password"
        // and we're autofilling without user interaction, there's nothing to do.
        if (!userTriggered && passwordACFieldName == "new-password") {
          lazy.log(
            "Not filling form, password field has the autocomplete new-password value."
          );
          autofillResult = AUTOFILL_RESULT.PASSWORD_AUTOCOMPLETE_NEW_PASSWORD;
          return;
        }

        // Don't clobber an existing password.
        if (passwordField.value && !clobberPassword) {
          lazy.log("Form not filled, the password field was already filled.");
          autofillResult = AUTOFILL_RESULT.EXISTING_PASSWORD;
          return;
        }
      }

      // Select a login to use for filling in the form.
      let selectedLogin;
      if (
        !clobberUsername &&
        usernameField &&
        (usernameField.value ||
          usernameField.disabled ||
          usernameField.readOnly)
      ) {
        // If username was specified in the field, it's disabled or it's readOnly, only fill in the
        // password if we find a matching login.
        let username = usernameField.value.toLowerCase();

        let matchingLogins = logins.filter(
          l => l.username.toLowerCase() == username
        );
        if (!matchingLogins.length) {
          lazy.log(
            "Password not filled. None of the stored logins match the username already present."
          );
          autofillResult = AUTOFILL_RESULT.EXISTING_USERNAME;
          return;
        }

        // If there are multiple, and one matches case, use it
        for (let l of matchingLogins) {
          if (l.username == usernameField.value) {
            selectedLogin = l;
          }
        }
        // Otherwise just use the first
        if (!selectedLogin) {
          selectedLogin = matchingLogins[0];
        }
      } else if (logins.length == 1) {
        selectedLogin = logins[0];
      } else {
        // We have multiple logins. Handle a special case here, for sites
        // which have a normal user+pass login *and* a password-only login
        // (eg, a PIN). Prefer the login that matches the type of the form
        // (user+pass or pass-only) when there's exactly one that matches.
        let matchingLogins;
        if (usernameField) {
          matchingLogins = logins.filter(l => l.username);
        } else {
          matchingLogins = logins.filter(l => !l.username);
        }

        if (matchingLogins.length != 1) {
          lazy.log("Multiple logins for form, so not filling any.");
          autofillResult = AUTOFILL_RESULT.MULTIPLE_LOGINS;
          return;
        }

        selectedLogin = matchingLogins[0];
      }

      // We will always have a selectedLogin at this point.

      if (!autofillForm) {
        lazy.log("autofillForms=false but form can be filled.");
        autofillResult = AUTOFILL_RESULT.NO_AUTOFILL_FORMS;
        return;
      }

      if (
        !userTriggered &&
        passwordACFieldName == "off" &&
        !lazy.LoginHelper.autofillAutocompleteOff
      ) {
        lazy.log(
          "Not autofilling the login because we're respecting autocomplete=off."
        );
        autofillResult = AUTOFILL_RESULT.AUTOCOMPLETE_OFF;
        return;
      }

      // Fill the form

      let willAutofill =
        usernameField || passwordField.value != selectedLogin.password;
      if (willAutofill) {
        let autoFilledLogin = {
          guid: selectedLogin.QueryInterface(Ci.nsILoginMetaInfo).guid,
          username: selectedLogin.username,
          usernameField: usernameField
            ? Cu.getWeakReference(usernameField)
            : null,
          password: selectedLogin.password,
          passwordField: passwordField
            ? Cu.getWeakReference(passwordField)
            : null,
        };
        // Ensure the state is updated before setUserInput is called.
        lazy.log(
          "Saving autoFilledLogin",
          autoFilledLogin.guid,
          "for",
          form.rootElement
        );
        docState.fillsByRootElement.set(form.rootElement, {
          login: autoFilledLogin,
          userTriggered,
        });
      }
      if (usernameField) {
        // Don't modify the username field because the user wouldn't be able to change it either.
        let disabledOrReadOnly =
          usernameField.disabled || usernameField.readOnly;

        if (selectedLogin.username && !disabledOrReadOnly) {
          let userNameDiffers = selectedLogin.username != usernameField.value;
          // Don't replace the username if it differs only in case, and the user triggered
          // this autocomplete. We assume that if it was user-triggered the entered text
          // is desired.
          let userEnteredDifferentCase =
            userTriggered &&
            userNameDiffers &&
            usernameField.value.toLowerCase() ==
              selectedLogin.username.toLowerCase();

          if (!userEnteredDifferentCase && userNameDiffers) {
            usernameField.setUserInput(selectedLogin.username);
          }
          LoginFormState._highlightFilledField(usernameField);
        }
      }

      if (passwordField) {
        if (passwordField.value != selectedLogin.password) {
          // Ensure the field gets re-masked in case a generated password was
          // filled into it previously.
          docState._stopTreatingAsGeneratedPasswordField(passwordField);

          passwordField.setUserInput(selectedLogin.password);
        }

        LoginFormState._highlightFilledField(passwordField);
      }

      if (style === "generatedPassword") {
        this._filledWithGeneratedPassword(passwordField);
      }

      lazy.log("_fillForm succeeded");
      if (passwordField) {
        autofillResult = AUTOFILL_RESULT.FILLED;
      } else if (usernameField) {
        autofillResult = AUTOFILL_RESULT.FILLED_USERNAME_ONLY_FORM;
      }
    } catch (ex) {
      console.error(ex);
      throw ex;
    } finally {
      if (!autofillResult) {
        // eslint-disable-next-line no-unsafe-finally
        throw new Error("_fillForm: autofillResult must be specified");
      }

      if (!userTriggered) {
        // Ignore fills as a result of user action for this probe.

        lazy.LoginManagerTelemetry.recordAutofillResult(autofillResult);

        if (usernameField) {
          let focusedElement = lazy.gFormFillService.focusedInput;
          if (
            usernameField == focusedElement &&
            ![
              AUTOFILL_RESULT.FILLED,
              AUTOFILL_RESULT.FILLED_USERNAME_ONLY_FORM,
            ].includes(autofillResult)
          ) {
            lazy.log(
              "Opening username autocomplete popup since the form wasn't autofilled."
            );
            lazy.gFormFillService.showPopup();
          }
        }
      }

      if (usernameField) {
        lazy.log("Attaching event listeners to usernameField.");
        usernameField.addEventListener("focus", observer);
        usernameField.addEventListener("mousedown", observer);
      }

      this.sendAsyncMessage("PasswordManager:formProcessed", {
        formid: form.rootElement.id,
        autofillResult,
      });
    }
  }

  getScenario(inputElement) {
    const docState = this.stateForDocument(inputElement.ownerDocument);
    return docState.getScenario(inputElement);
  }
}