5 files changed, 591 insertions, 2 deletions

diff --git a/remote/shared/webdriver/Accessibility.sys.mjs b/remote/shared/webdriver/Accessibility.sys.mjs
new file mode 100644
index 0000000000..4c7b2a6c69
--- /dev/null
+++ b/remote/shared/webdriver/Accessibility.sys.mjs
@@ -0,0 +1,519 @@
+/* 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/. */
+
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+  error: "chrome://remote/content/shared/webdriver/Errors.sys.mjs",
+  Log: "chrome://remote/content/shared/Log.sys.mjs",
+  waitForObserverTopic: "chrome://remote/content/marionette/sync.sys.mjs",
+});
+
+ChromeUtils.defineLazyGetter(lazy, "logger", () => lazy.Log.get());
+
+ChromeUtils.defineLazyGetter(lazy, "service", () => {
+  try {
+    return Cc["@mozilla.org/accessibilityService;1"].getService(
+      Ci.nsIAccessibilityService
+    );
+  } catch (e) {
+    lazy.logger.warn("Accessibility module is not present");
+    return undefined;
+  }
+});
+
+/** @namespace */
+export const accessibility = {
+  get service() {
+    return lazy.service;
+  },
+};
+
+/**
+ * Accessible states used to check element"s state from the accessiblity API
+ * perspective.
+ *
+ * Note: if gecko is built with --disable-accessibility, the interfaces
+ * are not defined. This is why we use getters instead to be able to use
+ * these statically.
+ */
+accessibility.State = {
+  get Unavailable() {
+    return Ci.nsIAccessibleStates.STATE_UNAVAILABLE;
+  },
+  get Focusable() {
+    return Ci.nsIAccessibleStates.STATE_FOCUSABLE;
+  },
+  get Selectable() {
+    return Ci.nsIAccessibleStates.STATE_SELECTABLE;
+  },
+  get Selected() {
+    return Ci.nsIAccessibleStates.STATE_SELECTED;
+  },
+};
+
+/**
+ * Accessible object roles that support some action.
+ */
+accessibility.ActionableRoles = new Set([
+  "checkbutton",
+  "check menu item",
+  "check rich option",
+  "combobox",
+  "combobox option",
+  "entry",
+  "key",
+  "link",
+  "listbox option",
+  "listbox rich option",
+  "menuitem",
+  "option",
+  "outlineitem",
+  "pagetab",
+  "pushbutton",
+  "radiobutton",
+  "radio menu item",
+  "rowheader",
+  "slider",
+  "spinbutton",
+  "switch",
+]);
+
+/**
+ * Factory function that constructs a new {@code accessibility.Checks}
+ * object with enforced strictness or not.
+ */
+accessibility.get = function (strict = false) {
+  return new accessibility.Checks(!!strict);
+};
+
+/**
+ * Wait for the document accessibility state to be different from STATE_BUSY.
+ *
+ * @param {Document} doc
+ *     The document to wait for.
+ * @returns {Promise}
+ *     A promise which resolves when the document's accessibility state is no
+ *     longer busy.
+ */
+function waitForDocumentAccessibility(doc) {
+  const documentAccessible = accessibility.service.getAccessibleFor(doc);
+  const state = {};
+  documentAccessible.getState(state, {});
+  if ((state.value & Ci.nsIAccessibleStates.STATE_BUSY) == 0) {
+    return Promise.resolve();
+  }
+
+  // Accessibility for the doc is busy, so wait for the state to change.
+  return lazy.waitForObserverTopic("accessible-event", {
+    checkFn: subject => {
+      // If event type does not match expected type, skip the event.
+      // If event's accessible does not match expected accessible,
+      // skip the event.
+      const event = subject.QueryInterface(Ci.nsIAccessibleEvent);
+      return (
+        event.eventType === Ci.nsIAccessibleEvent.EVENT_STATE_CHANGE &&
+        event.accessible === documentAccessible
+      );
+    },
+  });
+}
+
+/**
+ * Retrieve the Accessible for the provided element.
+ *
+ * @param {Element} element
+ *     The element for which we need to retrieve the accessible.
+ *
+ * @returns {nsIAccessible|null}
+ *     The Accessible object corresponding to the provided element or null if
+ *     the accessibility service is not available.
+ */
+accessibility.getAccessible = async function (element) {
+  if (!accessibility.service) {
+    return null;
+  }
+
+  // First, wait for accessibility to be ready for the element's document.
+  await waitForDocumentAccessibility(element.ownerDocument);
+
+  const acc = accessibility.service.getAccessibleFor(element);
+  if (acc) {
+    return acc;
+  }
+
+  // The Accessible doesn't exist yet. This can happen because a11y tree
+  // mutations happen during refresh driver ticks. Stop the refresh driver from
+  // doing its regular ticks and force two refresh driver ticks: the first to
+  // let layout update and notify a11y, and the second to let a11y process
+  // updates.
+  const windowUtils = element.ownerGlobal.windowUtils;
+  windowUtils.advanceTimeAndRefresh(0);
+  windowUtils.advanceTimeAndRefresh(0);
+  // Go back to normal refresh driver ticks.
+  windowUtils.restoreNormalRefresh();
+  return accessibility.service.getAccessibleFor(element);
+};
+
+/**
+ * Retrieve the accessible name for the provided element.
+ *
+ * @param {Element} element
+ *     The element for which we need to retrieve the accessible name.
+ *
+ * @returns {string}
+ *     The accessible name.
+ */
+accessibility.getAccessibleName = async function (element) {
+  const accessible = await accessibility.getAccessible(element);
+  if (!accessible) {
+    return "";
+  }
+
+  // If name is null (absent), expose the empty string.
+  if (accessible.name === null) {
+    return "";
+  }
+
+  return accessible.name;
+};
+
+/**
+ * Compute the role for the provided element.
+ *
+ * @param {Element} element
+ *     The element for which we need to compute the role.
+ *
+ * @returns {string}
+ *     The computed role.
+ */
+accessibility.getComputedRole = async function (element) {
+  const accessible = await accessibility.getAccessible(element);
+  if (!accessible) {
+    // If it's not in the a11y tree, it's probably presentational.
+    return "none";
+  }
+
+  return accessible.computedARIARole;
+};
+
+/**
+ * Component responsible for interacting with platform accessibility
+ * API.
+ *
+ * Its methods serve as wrappers for testing content and chrome
+ * accessibility as well as accessibility of user interactions.
+ */
+accessibility.Checks = class {
+  /**
+   * @param {boolean} strict
+   *     Flag indicating whether the accessibility issue should be logged
+   *     or cause an error to be thrown.  Default is to log to stdout.
+   */
+  constructor(strict) {
+    this.strict = strict;
+  }
+
+  /**
+   * Assert that the element has a corresponding accessible object, and retrieve
+   * this accessible. Note that if the accessibility.Checks component was
+   * created in non-strict mode, this helper will not attempt to resolve the
+   * accessible at all and will simply return null.
+   *
+   * @param {DOMElement|XULElement} element
+   *     Element to get the accessible object for.
+   * @param {boolean=} mustHaveAccessible
+   *     Flag indicating that the element must have an accessible object.
+   *     Defaults to not require this.
+   *
+   * @returns {Promise.<nsIAccessible>}
+   *     Promise with an accessibility object for the given element.
+   */
+  async assertAccessible(element, mustHaveAccessible = false) {
+    if (!this.strict) {
+      return null;
+    }
+
+    const accessible = await accessibility.getAccessible(element);
+    if (!accessible && mustHaveAccessible) {
+      this.error("Element does not have an accessible object", element);
+    }
+
+    return accessible;
+  }
+
+  /**
+   * Test if the accessible has a role that supports some arbitrary
+   * action.
+   *
+   * @param {nsIAccessible} accessible
+   *     Accessible object.
+   *
+   * @returns {boolean}
+   *     True if an actionable role is found on the accessible, false
+   *     otherwise.
+   */
+  isActionableRole(accessible) {
+    return accessibility.ActionableRoles.has(
+      accessibility.service.getStringRole(accessible.role)
+    );
+  }
+
+  /**
+   * Test if an accessible has at least one action that it supports.
+   *
+   * @param {nsIAccessible} accessible
+   *     Accessible object.
+   *
+   * @returns {boolean}
+   *     True if the accessible has at least one supported action,
+   *     false otherwise.
+   */
+  hasActionCount(accessible) {
+    return accessible.actionCount > 0;
+  }
+
+  /**
+   * Test if an accessible has a valid name.
+   *
+   * @param {nsIAccessible} accessible
+   *     Accessible object.
+   *
+   * @returns {boolean}
+   *     True if the accessible has a non-empty valid name, or false if
+   *     this is not the case.
+   */
+  hasValidName(accessible) {
+    return accessible.name && accessible.name.trim();
+  }
+
+  /**
+   * Test if an accessible has a {@code hidden} attribute.
+   *
+   * @param {nsIAccessible} accessible
+   *     Accessible object.
+   *
+   * @returns {boolean}
+   *     True if the accessible object has a {@code hidden} attribute,
+   *     false otherwise.
+   */
+  hasHiddenAttribute(accessible) {
+    let hidden = false;
+    try {
+      hidden = accessible.attributes.getStringProperty("hidden");
+    } catch (e) {}
+    // if the property is missing, error will be thrown
+    return hidden && hidden === "true";
+  }
+
+  /**
+   * Verify if an accessible has a given state.
+   * Test if an accessible has a given state.
+   *
+   * @param {nsIAccessible} accessible
+   *     Accessible object to test.
+   * @param {number} stateToMatch
+   *     State to match.
+   *
+   * @returns {boolean}
+   *     True if |accessible| has |stateToMatch|, false otherwise.
+   */
+  matchState(accessible, stateToMatch) {
+    let state = {};
+    accessible.getState(state, {});
+    return !!(state.value & stateToMatch);
+  }
+
+  /**
+   * Test if an accessible is hidden from the user.
+   *
+   * @param {nsIAccessible} accessible
+   *     Accessible object.
+   *
+   * @returns {boolean}
+   *     True if element is hidden from user, false otherwise.
+   */
+  isHidden(accessible) {
+    if (!accessible) {
+      return true;
+    }
+
+    while (accessible) {
+      if (this.hasHiddenAttribute(accessible)) {
+        return true;
+      }
+      accessible = accessible.parent;
+    }
+    return false;
+  }
+
+  /**
+   * Test if the element's visible state corresponds to its accessibility
+   * API visibility.
+   *
+   * @param {nsIAccessible} accessible
+   *     Accessible object.
+   * @param {DOMElement|XULElement} element
+   *     Element associated with |accessible|.
+   * @param {boolean} visible
+   *     Visibility state of |element|.
+   *
+   * @throws ElementNotAccessibleError
+   *     If |element|'s visibility state does not correspond to
+   *     |accessible|'s.
+   */
+  assertVisible(accessible, element, visible) {
+    let hiddenAccessibility = this.isHidden(accessible);
+
+    let message;
+    if (visible && hiddenAccessibility) {
+      message =
+        "Element is not currently visible via the accessibility API " +
+        "and may not be manipulated by it";
+    } else if (!visible && !hiddenAccessibility) {
+      message =
+        "Element is currently only visible via the accessibility API " +
+        "and can be manipulated by it";
+    }
+    this.error(message, element);
+  }
+
+  /**
+   * Test if the element's unavailable accessibility state matches the
+   * enabled state.
+   *
+   * @param {nsIAccessible} accessible
+   *     Accessible object.
+   * @param {DOMElement|XULElement} element
+   *     Element associated with |accessible|.
+   * @param {boolean} enabled
+   *     Enabled state of |element|.
+   *
+   * @throws ElementNotAccessibleError
+   *     If |element|'s enabled state does not match |accessible|'s.
+   */
+  assertEnabled(accessible, element, enabled) {
+    if (!accessible) {
+      return;
+    }
+
+    let win = element.ownerGlobal;
+    let disabledAccessibility = this.matchState(
+      accessible,
+      accessibility.State.Unavailable
+    );
+    let explorable =
+      win.getComputedStyle(element).getPropertyValue("pointer-events") !==
+      "none";
+
+    let message;
+    if (!explorable && !disabledAccessibility) {
+      message =
+        "Element is enabled but is not explorable via the " +
+        "accessibility API";
+    } else if (enabled && disabledAccessibility) {
+      message = "Element is enabled but disabled via the accessibility API";
+    } else if (!enabled && !disabledAccessibility) {
+      message = "Element is disabled but enabled via the accessibility API";
+    }
+    this.error(message, element);
+  }
+
+  /**
+   * Test if it is possible to activate an element with the accessibility
+   * API.
+   *
+   * @param {nsIAccessible} accessible
+   *     Accessible object.
+   * @param {DOMElement|XULElement} element
+   *     Element associated with |accessible|.
+   *
+   * @throws ElementNotAccessibleError
+   *     If it is impossible to activate |element| with |accessible|.
+   */
+  assertActionable(accessible, element) {
+    if (!accessible) {
+      return;
+    }
+
+    let message;
+    if (!this.hasActionCount(accessible)) {
+      message = "Element does not support any accessible actions";
+    } else if (!this.isActionableRole(accessible)) {
+      message =
+        "Element does not have a correct accessibility role " +
+        "and may not be manipulated via the accessibility API";
+    } else if (!this.hasValidName(accessible)) {
+      message = "Element is missing an accessible name";
+    } else if (!this.matchState(accessible, accessibility.State.Focusable)) {
+      message = "Element is not focusable via the accessibility API";
+    }
+
+    this.error(message, element);
+  }
+
+  /**
+   * Test that an element's selected state corresponds to its
+   * accessibility API selected state.
+   *
+   * @param {nsIAccessible} accessible
+   *     Accessible object.
+   * @param {DOMElement|XULElement} element
+   *     Element associated with |accessible|.
+   * @param {boolean} selected
+   *     The |element|s selected state.
+   *
+   * @throws ElementNotAccessibleError
+   *     If |element|'s selected state does not correspond to
+   *     |accessible|'s.
+   */
+  assertSelected(accessible, element, selected) {
+    if (!accessible) {
+      return;
+    }
+
+    // element is not selectable via the accessibility API
+    if (!this.matchState(accessible, accessibility.State.Selectable)) {
+      return;
+    }
+
+    let selectedAccessibility = this.matchState(
+      accessible,
+      accessibility.State.Selected
+    );
+
+    let message;
+    if (selected && !selectedAccessibility) {
+      message =
+        "Element is selected but not selected via the accessibility API";
+    } else if (!selected && selectedAccessibility) {
+      message =
+        "Element is not selected but selected via the accessibility API";
+    }
+    this.error(message, element);
+  }
+
+  /**
+   * Throw an error if strict accessibility checks are enforced and log
+   * the error to the log.
+   *
+   * @param {string} message
+   * @param {DOMElement|XULElement} element
+   *     Element that caused an error.
+   *
+   * @throws ElementNotAccessibleError
+   *     If |strict| is true.
+   */
+  error(message, element) {
+    if (!message || !this.strict) {
+      return;
+    }
+    if (element) {
+      let { id, tagName, className } = element;
+      message += `: id: ${id}, tagName: ${tagName}, className: ${className}`;
+    }
+
+    throw new lazy.error.ElementNotAccessibleError(message);
+  }
+};
diff --git a/remote/shared/webdriver/Actions.sys.mjs b/remote/shared/webdriver/Actions.sys.mjs
index 2639c4dc9f..2c21e989dd 100644
--- a/remote/shared/webdriver/Actions.sys.mjs
+++ b/remote/shared/webdriver/Actions.sys.mjs
@@ -1318,6 +1318,7 @@ class WheelScrollAction extends WheelAction {
       this.duration ?? tickDuration,
       deltaTarget =>
         this.performOneWheelScroll(
+          state,
           scrollCoordinates,
           deltaPosition,
           deltaTarget,
@@ -1329,12 +1330,19 @@ class WheelScrollAction extends WheelAction {
   /**
    * Perform one part of a wheel scroll corresponding to a specific emitted event.
    *
+   * @param {State} state - Actions state.
    * @param {Array<number>} scrollCoordinates - [x, y] viewport coordinates of the scroll.
    * @param {Array<number>} deltaPosition - [deltaX, deltaY] coordinates of the scroll before this event.
    * @param {Array<Array<number>>} deltaTargets - Array of [deltaX, deltaY] coordinates to scroll to.
    * @param {WindowProxy} win - Current window global.
    */
-  performOneWheelScroll(scrollCoordinates, deltaPosition, deltaTargets, win) {
+  performOneWheelScroll(
+    state,
+    scrollCoordinates,
+    deltaPosition,
+    deltaTargets,
+    win
+  ) {
     if (deltaTargets.length !== 1) {
       throw new Error("Can only scroll one wheel at a time");
     }
@@ -1350,6 +1358,7 @@ class WheelScrollAction extends WheelAction {
       deltaY,
       deltaZ: 0,
     });
+    eventData.update(state);
 
     lazy.event.synthesizeWheelAtPoint(
       scrollCoordinates[0],
@@ -2237,6 +2246,22 @@ class WheelEventData extends InputEventData {
     this.deltaY = deltaY;
     this.deltaZ = deltaZ;
     this.deltaMode = deltaMode;
+
+    this.altKey = false;
+    this.ctrlKey = false;
+    this.metaKey = false;
+    this.shiftKey = false;
+  }
+
+  update(state) {
+    // set modifier properties based on whether any corresponding keys are
+    // pressed on any key input source
+    for (const [, otherInputSource] of state.inputSourcesByType("key")) {
+      this.altKey = otherInputSource.alt || this.altKey;
+      this.ctrlKey = otherInputSource.ctrl || this.ctrlKey;
+      this.metaKey = otherInputSource.meta || this.metaKey;
+      this.shiftKey = otherInputSource.shift || this.shiftKey;
+    }
   }
 }
 
diff --git a/remote/shared/webdriver/Assert.sys.mjs b/remote/shared/webdriver/Assert.sys.mjs
index 6c254173aa..fe83bc9181 100644
--- a/remote/shared/webdriver/Assert.sys.mjs
+++ b/remote/shared/webdriver/Assert.sys.mjs
@@ -410,6 +410,36 @@ assert.object = function (obj, msg = "") {
 };
 
 /**
+ * Asserts that <var>obj</var> is an instance of a specified class.
+ * <var>constructor</var> should have a static isInstance method implemented.
+ *
+ * @param {?} obj
+ *     Value to test.
+ * @param {?} constructor
+ *     Class constructor.
+ * @param {string=} msg
+ *     Custom error message.
+ *
+ * @returns {object}
+ *     <var>obj</var> is returned unaltered.
+ *
+ * @throws {InvalidArgumentError}
+ *     If <var>obj</var> is not an instance of a specified class.
+ */
+assert.isInstance = function (obj, constructor, msg = "") {
+  assert.object(obj, msg);
+  assert.object(constructor.prototype, msg);
+
+  msg =
+    msg ||
+    lazy.pprint`Expected ${obj} to be an instance of ${constructor.name}`;
+  return assert.that(
+    o => Object.hasOwn(constructor, "isInstance") && constructor.isInstance(o),
+    msg
+  )(obj);
+};
+
+/**
  * Asserts that <var>prop</var> is in <var>obj</var>.
  *
  * @param {?} prop
diff --git a/remote/shared/webdriver/Session.sys.mjs b/remote/shared/webdriver/Session.sys.mjs
index edffeea7b6..3d7b074ac9 100644
--- a/remote/shared/webdriver/Session.sys.mjs
+++ b/remote/shared/webdriver/Session.sys.mjs
@@ -5,7 +5,8 @@
 const lazy = {};
 
 ChromeUtils.defineESModuleGetters(lazy, {
-  accessibility: "chrome://remote/content/marionette/accessibility.sys.mjs",
+  accessibility:
+    "chrome://remote/content/shared/webdriver/Accessibility.sys.mjs",
   allowAllCerts: "chrome://remote/content/marionette/cert.sys.mjs",
   Capabilities: "chrome://remote/content/shared/webdriver/Capabilities.sys.mjs",
   error: "chrome://remote/content/shared/webdriver/Errors.sys.mjs",
diff --git a/remote/shared/webdriver/test/xpcshell/test_Assert.js b/remote/shared/webdriver/test/xpcshell/test_Assert.js
index cf474868b6..aabd8656dd 100644
--- a/remote/shared/webdriver/test/xpcshell/test_Assert.js
+++ b/remote/shared/webdriver/test/xpcshell/test_Assert.js
@@ -150,6 +150,20 @@ add_task(function test_object() {
   Assert.throws(() => assert.object(null, "custom"), /custom/);
 });
 
+add_task(function test_isInstance() {
+  class Foo {
+    static isInstance(obj) {
+      return obj instanceof Foo;
+    }
+  }
+  assert.isInstance(new Foo(), Foo);
+  for (let typ of [{}, 42, "foo", true, null, undefined]) {
+    Assert.throws(() => assert.isInstance(typ, Foo), /InvalidArgumentError/);
+  }
+
+  Assert.throws(() => assert.isInstance(null, null, "custom"), /custom/);
+});
+
 add_task(function test_in() {
   assert.in("foo", { foo: 42 });
   for (let typ of [{}, 42, true, null, undefined]) {