commands/FBAccessibilityCommands.py

#!/usr/bin/python

# Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved
#
# This source code is licensed under the MIT license found in the
# LICENSE file in the root directory of this source tree.

import os
import re

import fbchisellldbbase as fb
import fbchisellldbobjecthelpers as objHelpers


# This is the key corresponding to accessibility label in
# _accessibilityElementsInContainer:
ACCESSIBILITY_LABEL_KEY = 2001


def lldbcommands():
    return [
        FBPrintAccessibilityLabels(),
        FBPrintAccessibilityIdentifiers(),
        FBFindViewByAccessibilityLabelCommand(),
    ]


class FBPrintAccessibilityLabels(fb.FBCommand):
    def name(self):
        return "pa11y"

    def description(self):
        return "Print accessibility labels of all views in hierarchy of <aView>"

    def args(self):
        return [
            fb.FBCommandArgument(
                arg="aView",
                type="UIView*",
                help="The view to print the hierarchy of.",
                default="(id)[[UIApplication sharedApplication] keyWindow]",
            )
        ]

    def run(self, arguments, options):
        forceStartAccessibilityServer()
        printAccessibilityHierarchy(arguments[0])


class FBPrintAccessibilityIdentifiers(fb.FBCommand):
    def name(self):
        return "pa11yi"

    def description(self):
        return "Print accessibility identifiers of all views in hierarchy of <aView>"

    def args(self):
        return [
            fb.FBCommandArgument(
                arg="aView",
                type="UIView*",
                help="The view to print the hierarchy of.",
                default="(id)[[UIApplication sharedApplication] keyWindow]",
            )
        ]

    def run(self, arguments, option):
        forceStartAccessibilityServer()
        printAccessibilityIdentifiersHierarchy(arguments[0])


class FBFindViewByAccessibilityLabelCommand(fb.FBCommand):
    def name(self):
        return "fa11y"

    def description(self):
        return (
            "Find the views whose accessibility labels match labelRegex "
            "and puts the address of the first result on the clipboard."
        )

    def args(self):
        return [
            fb.FBCommandArgument(
                arg="labelRegex",
                type="string",
                help="The accessibility label regex to search the view hierarchy for.",
            )
        ]

    def accessibilityGrepHierarchy(self, view, needle):
        a11yLabel = accessibilityLabel(view)
        # if we don't have any accessibility string - we should have some children
        if int(a11yLabel.GetValue(), 16) == 0:
            # We call private method that gives back all visible accessibility children
            # for view iOS 10 and higher
            if fb.evaluateBooleanExpression(
                "[UIView respondsToSelector:@selector(_accessibilityElementsAndContainersDescendingFromViews:options:sorted:)]"
            ):
                accessibilityElements = fb.evaluateObjectExpression(
                    "[UIView _accessibilityElementsAndContainersDescendingFromViews:@[(id)%s] options:0 sorted:NO]"
                    % view
                )
            else:
                accessibilityElements = fb.evaluateObjectExpression(
                    "[[[UIApplication sharedApplication] keyWindow] _accessibilityElementsInContainer:0 topLevel:%s includeKB:0]"
                    % view
                )
            accessibilityElementsCount = fb.evaluateIntegerExpression(
                "[%s count]" % accessibilityElements
            )
            for index in range(0, accessibilityElementsCount):
                subview = fb.evaluateObjectExpression(
                    "[%s objectAtIndex:%i]" % (accessibilityElements, index)
                )
                self.accessibilityGrepHierarchy(subview, needle)
        elif re.match(
            r".*" + needle + ".*", a11yLabel.GetObjectDescription(), re.IGNORECASE
        ):
            classDesc = objHelpers.className(view)
            print(
                "({} {}) {}".format(classDesc, view, a11yLabel.GetObjectDescription())
            )

            # First element that is found is copied to clipboard
            if not self.foundElement:
                self.foundElement = True
                cmd = 'echo %s | tr -d "\n" | pbcopy' % view
                os.system(cmd)

    def run(self, arguments, options):
        forceStartAccessibilityServer()
        rootView = fb.evaluateObjectExpression(
            "[[UIApplication sharedApplication] keyWindow]"
        )
        self.foundElement = False
        self.accessibilityGrepHierarchy(rootView, arguments[0])


def isRunningInSimulator():
    return (
        fb.evaluateExpressionValue("(id)[[UIDevice currentDevice] model]")
        .GetObjectDescription()
        .lower()
        .find("simulator")
        >= 0
    ) or (
        fb.evaluateExpressionValue("(id)[[UIDevice currentDevice] name]")
        .GetObjectDescription()
        .lower()
        .find("simulator")
        >= 0
    )


def forceStartAccessibilityServer():
    # We try to start accessibility server only if we don't have needed method active
    if not fb.evaluateBooleanExpression(
        "[UIView instancesRespondToSelector:@selector(_accessibilityElementsInContainer:)]"
    ):
        # Starting accessibility server is different for simulator and device
        if isRunningInSimulator():
            fb.evaluateEffect(
                "[[UIApplication sharedApplication] accessibilityActivate]"
            )
        else:
            fb.evaluateEffect(
                "[[[UIApplication sharedApplication] _accessibilityBundlePrincipalClass] _accessibilityStartServer]"
            )


def accessibilityLabel(view):
    # using Apple private API to get real value of accessibility string for element.
    return fb.evaluateExpressionValue(
        "(id)[%s accessibilityAttributeValue:%i]" % (view, ACCESSIBILITY_LABEL_KEY),
        False,
    )


def accessibilityIdentifier(view):
    return fb.evaluateExpressionValue(
        "(id)[{} accessibilityIdentifier]".format(view), False
    )


def accessibilityElements(view):
    if fb.evaluateBooleanExpression(
        "[UIView instancesRespondToSelector:@selector(accessibilityElements)]"
    ):
        a11yElements = fb.evaluateExpression(
            "(id)[%s accessibilityElements]" % view, False
        )
        if int(a11yElements, 16) != 0:
            return a11yElements
    if fb.evaluateBooleanExpression(
        "[%s respondsToSelector:@selector(_accessibleSubviews)]" % view
    ):
        return fb.evaluateExpression("(id)[%s _accessibleSubviews]" % (view), False)
    else:
        return fb.evaluateObjectExpression(
            "[[[UIApplication sharedApplication] keyWindow] _accessibilityElementsInContainer:0 topLevel:%s includeKB:0]"
            % view
        )


def printAccessibilityHierarchy(view, indent=0):
    a11yLabel = accessibilityLabel(view)
    classDesc = objHelpers.className(view)
    indentString = "   | " * indent

    # if we don't have any accessibility string - we should have some children
    if int(a11yLabel.GetValue(), 16) == 0:
        print(indentString + ("{} {}".format(classDesc, view)))
        # We call private method that gives back all visible accessibility children
        # for view
        a11yElements = accessibilityElements(view)
        accessibilityElementsCount = int(
            fb.evaluateExpression("(int)[%s count]" % a11yElements)
        )
        for index in range(0, accessibilityElementsCount):
            subview = fb.evaluateObjectExpression(
                "[%s objectAtIndex:%i]" % (a11yElements, index)
            )
            printAccessibilityHierarchy(subview, indent + 1)
    else:
        print(
            indentString
            + ("({} {}) {}".format(classDesc, view, a11yLabel.GetObjectDescription()))
        )


def printAccessibilityIdentifiersHierarchy(view, indent=0):
    a11yIdentifier = accessibilityIdentifier(view)
    classDesc = objHelpers.className(view)
    indentString = "   | " * indent

    # if we don't have any accessibility identifier - we should have some children
    if int(a11yIdentifier.GetValue(), 16) == 0:
        print(indentString + ("{} {}".format(classDesc, view)))
        # We call private method that gives back all visible accessibility children
        # for view
        a11yElements = accessibilityElements(view)
        accessibilityElementsCount = int(
            fb.evaluateExpression("(int)[%s count]" % a11yElements)
        )
        for index in range(0, accessibilityElementsCount):
            subview = fb.evaluateObjectExpression(
                "[%s objectAtIndex:%i]" % (a11yElements, index)
            )
            printAccessibilityIdentifiersHierarchy(subview, indent + 1)
    else:
        print(
            indentString
            + (
                "({} {}) {}".format(
                    classDesc, view, a11yIdentifier.GetObjectDescription()
                )
            )
        )