/*
* Copyright (C) 2016-2022 Yomichan Authors
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see .
*/
/* global
* DOMTextScanner
* TextSourceElement
* TextSourceRange
*/
/**
* This class contains utility functions related to the HTML document.
*/
class DocumentUtil {
/**
* Options to configure how element detection is performed.
* @typedef {object} GetRangeFromPointOptions
* @property {boolean} deepContentScan Whether or deep content scanning should be performed. When deep content scanning is enabled,
* some transparent overlay elements will be ignored when looking for the element at the input position.
* @property {boolean} normalizeCssZoom Whether or not zoom coordinates should be normalized.
*/
/**
* Scans the document for text or elements with text information at the given coordinate.
* Coordinates are provided in [client space](https://developer.mozilla.org/en-US/docs/Web/CSS/CSSOM_View/Coordinate_systems).
* @callback GetRangeFromPointHandler
* @param {number} x The x coordinate to search at.
* @param {number} y The y coordinate to search at.
* @param {GetRangeFromPointOptions} options Options to configure how element detection is performed.
* @returns {?TextSourceRange|TextSourceElement} A range for the hovered text or element, or `null` if no applicable content was found.
*/
/**
* Scans the document for text or elements with text information at the given coordinate.
* Coordinates are provided in [client space](https://developer.mozilla.org/en-US/docs/Web/CSS/CSSOM_View/Coordinate_systems).
* @param {number} x The x coordinate to search at.
* @param {number} y The y coordinate to search at.
* @param {GetRangeFromPointOptions} options Options to configure how element detection is performed.
* @returns {?TextSourceRange|TextSourceElement} A range for the hovered text or element, or `null` if no applicable content was found.
*/
static getRangeFromPoint(x, y, options) {
for (const handler of this._getRangeFromPointHandlers) {
const r = handler(x, y, options);
if (r !== null) { return r; }
}
const {deepContentScan, normalizeCssZoom} = options;
const elements = this._getElementsFromPoint(x, y, deepContentScan);
let imposter = null;
let imposterContainer = null;
let imposterSourceElement = null;
if (elements.length > 0) {
const element = elements[0];
switch (element.nodeName.toUpperCase()) {
case 'IMG':
case 'BUTTON':
case 'SELECT':
return TextSourceElement.create(element);
case 'INPUT':
if (element.type === 'text') {
imposterSourceElement = element;
[imposter, imposterContainer] = this._createImposter(element, false);
}
break;
case 'TEXTAREA':
imposterSourceElement = element;
[imposter, imposterContainer] = this._createImposter(element, true);
break;
}
}
const range = this._caretRangeFromPointExt(x, y, deepContentScan ? elements : [], normalizeCssZoom);
if (range !== null) {
if (imposter !== null) {
this._setImposterStyle(imposterContainer.style, 'z-index', '-2147483646');
this._setImposterStyle(imposter.style, 'pointer-events', 'none');
return TextSourceRange.createFromImposter(range, imposterContainer, imposterSourceElement);
}
return TextSourceRange.create(range);
} else {
if (imposterContainer !== null) {
imposterContainer.parentNode.removeChild(imposterContainer);
}
return null;
}
}
/**
* Registers a custom handler for scanning for text or elements at the input position.
* @param {GetRangeFromPointHandler} handler The handler callback which will be invoked when calling `getRangeFromPoint`.
*/
static registerGetRangeFromPointHandler(handler) {
this._getRangeFromPointHandlers.push(handler);
}
/**
* Extract a sentence from a document.
* @param {TextSourceRange|TextSourceElement} source The text source object, either `TextSourceRange` or `TextSourceElement`.
* @param {boolean} layoutAwareScan Whether or not layout-aware scan mode should be used.
* @param {number} extent The length of the sentence to extract.
* @param {boolean} terminateAtNewlines Whether or not a sentence should be terminated at newline characters.
* @param {Map} terminatorMap A mapping of characters that terminate a sentence.
* Format:
* ```js
* new Map([ [character: string, [includeCharacterAtStart: boolean, includeCharacterAtEnd: boolean]], ... ])
* ```
* @param {Map} forwardQuoteMap A mapping of quote characters that delimit a sentence.
* Format:
* ```js
* new Map([ [character: string, [otherCharacter: string, includeCharacterAtStart: boolean]], ... ])
* ```
* @param {Map} backwardQuoteMap A mapping of quote characters that delimit a sentence,
* which is the inverse of forwardQuoteMap.
* Format:
* ```js
* new Map([ [character: string, [otherCharacter: string, includeCharacterAtEnd: boolean]], ... ])
* ```
* @returns {{sentence: string, offset: number}} The sentence and the offset to the original source.
*/
static extractSentence(source, layoutAwareScan, extent, terminateAtNewlines, terminatorMap, forwardQuoteMap, backwardQuoteMap) {
// Scan text
source = source.clone();
const startLength = source.setStartOffset(extent, layoutAwareScan);
const endLength = source.setEndOffset(extent * 2 - startLength, true, layoutAwareScan);
const text = source.text();
const textLength = text.length;
const textEndAnchor = textLength - endLength;
let pos1 = startLength;
let pos2 = textEndAnchor;
// Move backward
let quoteStack = [];
for (; pos1 > 0; --pos1) {
const c = text[pos1 - 1];
if (c === '\n' && terminateAtNewlines) { break; }
if (quoteStack.length === 0) {
const terminatorInfo = terminatorMap.get(c);
if (typeof terminatorInfo !== 'undefined') {
if (terminatorInfo[0]) { --pos1; }
break;
}
}
let quoteInfo = forwardQuoteMap.get(c);
if (typeof quoteInfo !== 'undefined') {
if (quoteStack.length === 0) {
if (quoteInfo[1]) { --pos1; }
break;
} else if (quoteStack[0] === c) {
quoteStack.pop();
continue;
}
}
quoteInfo = backwardQuoteMap.get(c);
if (typeof quoteInfo !== 'undefined') {
quoteStack.unshift(quoteInfo[0]);
}
}
// Move forward
quoteStack = [];
for (; pos2 < textLength; ++pos2) {
const c = text[pos2];
if (c === '\n' && terminateAtNewlines) { break; }
if (quoteStack.length === 0) {
const terminatorInfo = terminatorMap.get(c);
if (typeof terminatorInfo !== 'undefined') {
if (terminatorInfo[1]) { ++pos2; }
break;
}
}
let quoteInfo = backwardQuoteMap.get(c);
if (typeof quoteInfo !== 'undefined') {
if (quoteStack.length === 0) {
if (quoteInfo[1]) { ++pos2; }
break;
} else if (quoteStack[0] === c) {
quoteStack.pop();
continue;
}
}
quoteInfo = forwardQuoteMap.get(c);
if (typeof quoteInfo !== 'undefined') {
quoteStack.unshift(quoteInfo[0]);
}
}
// Trim whitespace
for (; pos1 < startLength && this._isWhitespace(text[pos1]); ++pos1) { /* NOP */ }
for (; pos2 > textEndAnchor && this._isWhitespace(text[pos2 - 1]); --pos2) { /* NOP */ }
// Result
return {
text: text.substring(pos1, pos2),
offset: startLength - pos1
};
}
/**
* Computes the scaling adjustment that is necessary for client space coordinates based on the
* CSS zoom level.
* @param {Node} node A node in the document.
* @returns {number} The scaling factor.
*/
static computeZoomScale(node) {
if (this._cssZoomSupported === null) {
this._cssZoomSupported = (typeof document.createElement('div').style.zoom === 'string');
}
if (!this._cssZoomSupported) { return 1; }
// documentElement must be excluded because the computer style of its zoom property is inconsistent.
// * If CSS `:root{zoom:X;}` is specified, the computed zoom will always report `X`.
// * If CSS `:root{zoom:X;}` is not specified, the computed zoom report the browser's zoom level.
// Therefor, if CSS root zoom is specified as a value other than 1, the adjusted {x, y} values
// would be incorrect, which is not new behaviour.
let scale = 1;
const {ELEMENT_NODE, DOCUMENT_FRAGMENT_NODE} = Node;
const {documentElement} = document;
for (; node !== null && node !== documentElement; node = node.parentNode) {
const {nodeType} = node;
if (nodeType === DOCUMENT_FRAGMENT_NODE) {
const {host} = node;
if (typeof host !== 'undefined') {
node = host;
}
continue;
} else if (nodeType !== ELEMENT_NODE) {
continue;
}
let {zoom} = getComputedStyle(node);
if (typeof zoom !== 'string') { continue; }
zoom = Number.parseFloat(zoom);
if (!Number.isFinite(zoom) || zoom === 0) { continue; }
scale *= zoom;
}
return scale;
}
/**
* Converts a rect based on the CSS zoom scaling for a given node.
* @param {DOMRect} rect The rect to convert.
* @param {Node} node The node to compute the zoom from.
* @returns {DOMRect} The updated rect, or the same rect if no change is needed.
*/
static convertRectZoomCoordinates(rect, node) {
const scale = this.computeZoomScale(node);
return (scale === 1 ? rect : new DOMRect(rect.left * scale, rect.top * scale, rect.width * scale, rect.height * scale));
}
/**
* Converts multiple rects based on the CSS zoom scaling for a given node.
* @param {DOMRect[]} rects The rects to convert.
* @param {Node} node The node to compute the zoom from.
* @returns {DOMRect[]} The updated rects, or the same rects array if no change is needed.
*/
static convertMultipleRectZoomCoordinates(rects, node) {
const scale = this.computeZoomScale(node);
if (scale === 1) { return rects; }
const results = [];
for (const rect of rects) {
results.push(new DOMRect(rect.left * scale, rect.top * scale, rect.width * scale, rect.height * scale));
}
return results;
}
/**
* Checks whether a given point is contained within a rect.
* @param {number} x The horizontal coordinate.
* @param {number} y The vertical coordinate.
* @param {DOMRect} rect The rect to check.
* @returns {boolean} `true` if the point is inside the rect, `false` otherwise.
*/
static isPointInRect(x, y, rect) {
return (
x >= rect.left && x < rect.right &&
y >= rect.top && y < rect.bottom
);
}
/**
* Checks whether a given point is contained within any rect in a list.
* @param {number} x The horizontal coordinate.
* @param {number} y The vertical coordinate.
* @param {DOMRect[]} rects The rect to check.
* @returns {boolean} `true` if the point is inside any of the rects, `false` otherwise.
*/
static isPointInAnyRect(x, y, rects) {
for (const rect of rects) {
if (this.isPointInRect(x, y, rect)) {
return true;
}
}
return false;
}
/**
* Checks whether a given point is contained within a selection range.
* @param {number} x The horizontal coordinate.
* @param {number} y The vertical coordinate.
* @param {Selection} selection The selection to check.
* @returns {boolean} `true` if the point is inside the selection, `false` otherwise.
*/
static isPointInSelection(x, y, selection) {
for (let i = 0; i < selection.rangeCount; ++i) {
const range = selection.getRangeAt(i);
if (this.isPointInAnyRect(x, y, range.getClientRects())) {
return true;
}
}
return false;
}
/**
* Gets an array of the active modifier keys.
* @param {KeyboardEvent|MouseEvent|TouchEvent} event The event to check.
* @returns {string[]} An array of modifiers.
*/
static getActiveModifiers(event) {
const modifiers = [];
if (event.altKey) { modifiers.push('alt'); }
if (event.ctrlKey) { modifiers.push('ctrl'); }
if (event.metaKey) { modifiers.push('meta'); }
if (event.shiftKey) { modifiers.push('shift'); }
return modifiers;
}
/**
* Gets an array of the active modifier keys and buttons.
* @param {KeyboardEvent|MouseEvent|TouchEvent} event The event to check.
* @returns {string[]} An array of modifiers and buttons.
*/
static getActiveModifiersAndButtons(event) {
const modifiers = this.getActiveModifiers(event);
this._getActiveButtons(event, modifiers);
return modifiers;
}
/**
* Gets an array of the active buttons.
* @param {KeyboardEvent|MouseEvent|TouchEvent} event The event to check.
* @returns {string[]} An array of modifiers and buttons.
*/
static getActiveButtons(event) {
const buttons = [];
this._getActiveButtons(event, buttons);
return buttons;
}
/**
* Adds a fullscreen change event listener. This function handles all of the browser-specific variants.
* @param {Function} onFullscreenChanged The event callback.
* @param {?EventListenerCollection} eventListenerCollection An optional `EventListenerCollection` to add the registration to.
*/
static addFullscreenChangeEventListener(onFullscreenChanged, eventListenerCollection=null) {
const target = document;
const options = false;
const fullscreenEventNames = [
'fullscreenchange',
'MSFullscreenChange',
'mozfullscreenchange',
'webkitfullscreenchange'
];
for (const eventName of fullscreenEventNames) {
if (eventListenerCollection === null) {
target.addEventListener(eventName, onFullscreenChanged, options);
} else {
eventListenerCollection.addEventListener(target, eventName, onFullscreenChanged, options);
}
}
}
/**
* Returns the current fullscreen element. This function handles all of the browser-specific variants.
* @returns {?Element} The current fullscreen element, or `null` if the window is not fullscreen.
*/
static getFullscreenElement() {
return (
document.fullscreenElement ||
document.msFullscreenElement ||
document.mozFullScreenElement ||
document.webkitFullscreenElement ||
null
);
}
/**
* Gets all of the nodes within a `Range`.
* @param {Range} range The range to check.
* @returns {Node[]} The list of nodes.
*/
static getNodesInRange(range) {
const end = range.endContainer;
const nodes = [];
for (let node = range.startContainer; node !== null; node = this.getNextNode(node)) {
nodes.push(node);
if (node === end) { break; }
}
return nodes;
}
/**
* Gets the next node after a specified node. This traverses the DOM in its logical order.
* @param {Node} node The node to start at.
* @returns {?Node} The next node, or `null` if there is no next node.
*/
static getNextNode(node) {
let next = node.firstChild;
if (next === null) {
while (true) {
next = node.nextSibling;
if (next !== null) { break; }
next = node.parentNode;
if (next === null) { break; }
node = next;
}
}
return next;
}
/**
* Checks whether any node in a list of nodes matches a selector.
* @param {Node[]} nodes The list of ndoes to check.
* @param {string} selector The selector to test.
* @returns {boolean} `true` if any element node matches the selector, `false` otherwise.
*/
static anyNodeMatchesSelector(nodes, selector) {
const ELEMENT_NODE = Node.ELEMENT_NODE;
for (let node of nodes) {
for (; node !== null; node = node.parentNode) {
if (node.nodeType !== ELEMENT_NODE) { continue; }
if (node.matches(selector)) { return true; }
break;
}
}
return false;
}
/**
* Checks whether every node in a list of nodes matches a selector.
* @param {Node[]} nodes The list of ndoes to check.
* @param {string} selector The selector to test.
* @returns {boolean} `true` if every element node matches the selector, `false` otherwise.
*/
static everyNodeMatchesSelector(nodes, selector) {
const ELEMENT_NODE = Node.ELEMENT_NODE;
for (let node of nodes) {
while (true) {
if (node === null) { return false; }
if (node.nodeType === ELEMENT_NODE && node.matches(selector)) { break; }
node = node.parentNode;
}
}
return true;
}
/**
* Checks whether the meta key is supported in the browser on the specified operating system.
* @param {string} os The operating system to check.
* @param {string} browser The browser to check.
* @returns {boolean} `true` if supported, `false` otherwise.
*/
static isMetaKeySupported(os, browser) {
return !(browser === 'firefox' || browser === 'firefox-mobile') || os === 'mac';
}
/**
* Checks whether an element on the page that can accept input is focused.
* @returns {boolean} `true` if an input element is focused, `false` otherwise.
*/
static isInputElementFocused() {
const element = document.activeElement;
if (element === null) { return false; }
const type = element.nodeName.toUpperCase();
switch (type) {
case 'INPUT':
case 'TEXTAREA':
case 'SELECT':
return true;
default:
return element.isContentEditable;
}
}
/**
* Offsets an array of DOMRects by a given amount.
* @param {DOMRect[]} rects The DOMRects to offset.
* @param {number} x The horizontal offset amount.
* @param {number} y The vertical offset amount.
* @returns {DOMRect} The DOMRects with the offset applied.
*/
static offsetDOMRects(rects, x, y) {
const results = [];
for (const rect of rects) {
results.push(new DOMRect(rect.left + x, rect.top + y, rect.width, rect.height));
}
return results;
}
/**
* Gets the parent writing mode of an element.
* See: https://developer.mozilla.org/en-US/docs/Web/CSS/writing-mode.
* @param {Element} element The HTML element to check.
* @returns {string} The writing mode.
*/
static getElementWritingMode(element) {
if (element !== null) {
const {writingMode} = getComputedStyle(element);
if (typeof writingMode === 'string') {
return this.normalizeWritingMode(writingMode);
}
}
return 'horizontal-tb';
}
/**
* Normalizes a CSS writing mode value by converting non-standard and deprecated values
* into their corresponding standard vaules.
* @param {string} writingMode The writing mode to normalize.
* @returns {string} The normalized writing mode.
*/
static normalizeWritingMode(writingMode) {
switch (writingMode) {
case 'lr':
case 'lr-tb':
case 'rl':
return 'horizontal-tb';
case 'tb':
return 'vertical-lr';
case 'tb-rl':
return 'vertical-rl';
default:
return writingMode;
}
}
/**
* Converts a value from an element to a number.
* @param {string} value A string representation of a number.
* @param {object} constraints An object which might contain `min`, `max`, and `step` fields which are used to constrain the value.
* @returns {number} The parsed and constrained number.
*/
static convertElementValueToNumber(value, constraints) {
value = parseFloat(value);
if (!Number.isFinite(value)) { value = 0; }
let {min, max, step} = constraints;
min = this._convertToNumberOrNull(min);
max = this._convertToNumberOrNull(max);
step = this._convertToNumberOrNull(step);
if (typeof min === 'number') { value = Math.max(value, min); }
if (typeof max === 'number') { value = Math.min(value, max); }
if (typeof step === 'number' && step !== 0) { value = Math.round(value / step) * step; }
return value;
}
// Private
static _getActiveButtons(event, array) {
let {buttons} = event;
if (typeof buttons === 'number' && buttons > 0) {
for (let i = 0; i < 6; ++i) {
const buttonFlag = (1 << i);
if ((buttons & buttonFlag) !== 0) {
array.push(`mouse${i}`);
buttons &= ~buttonFlag;
if (buttons === 0) { break; }
}
}
}
}
static _setImposterStyle(style, propertyName, value) {
style.setProperty(propertyName, value, 'important');
}
static _createImposter(element, isTextarea) {
const body = document.body;
if (body === null) { return [null, null]; }
const elementStyle = window.getComputedStyle(element);
const elementRect = element.getBoundingClientRect();
const documentRect = document.documentElement.getBoundingClientRect();
let left = elementRect.left - documentRect.left;
let top = elementRect.top - documentRect.top;
// Container
const container = document.createElement('div');
const containerStyle = container.style;
this._setImposterStyle(containerStyle, 'all', 'initial');
this._setImposterStyle(containerStyle, 'position', 'absolute');
this._setImposterStyle(containerStyle, 'left', '0');
this._setImposterStyle(containerStyle, 'top', '0');
this._setImposterStyle(containerStyle, 'width', `${documentRect.width}px`);
this._setImposterStyle(containerStyle, 'height', `${documentRect.height}px`);
this._setImposterStyle(containerStyle, 'overflow', 'hidden');
this._setImposterStyle(containerStyle, 'opacity', '0');
this._setImposterStyle(containerStyle, 'pointer-events', 'none');
this._setImposterStyle(containerStyle, 'z-index', '2147483646');
// Imposter
const imposter = document.createElement('div');
const imposterStyle = imposter.style;
let value = element.value;
if (value.endsWith('\n')) { value += '\n'; }
imposter.textContent = value;
for (let i = 0, ii = elementStyle.length; i < ii; ++i) {
const property = elementStyle[i];
this._setImposterStyle(imposterStyle, property, elementStyle.getPropertyValue(property));
}
this._setImposterStyle(imposterStyle, 'position', 'absolute');
this._setImposterStyle(imposterStyle, 'top', `${top}px`);
this._setImposterStyle(imposterStyle, 'left', `${left}px`);
this._setImposterStyle(imposterStyle, 'margin', '0');
this._setImposterStyle(imposterStyle, 'pointer-events', 'auto');
if (isTextarea) {
if (elementStyle.overflow === 'visible') {
this._setImposterStyle(imposterStyle, 'overflow', 'auto');
}
} else {
this._setImposterStyle(imposterStyle, 'overflow', 'hidden');
this._setImposterStyle(imposterStyle, 'white-space', 'nowrap');
this._setImposterStyle(imposterStyle, 'line-height', elementStyle.height);
}
container.appendChild(imposter);
body.appendChild(container);
// Adjust size
const imposterRect = imposter.getBoundingClientRect();
if (imposterRect.width !== elementRect.width || imposterRect.height !== elementRect.height) {
const width = parseFloat(elementStyle.width) + (elementRect.width - imposterRect.width);
const height = parseFloat(elementStyle.height) + (elementRect.height - imposterRect.height);
this._setImposterStyle(imposterStyle, 'width', `${width}px`);
this._setImposterStyle(imposterStyle, 'height', `${height}px`);
}
if (imposterRect.left !== elementRect.left || imposterRect.top !== elementRect.top) {
left += (elementRect.left - imposterRect.left);
top += (elementRect.top - imposterRect.top);
this._setImposterStyle(imposterStyle, 'left', `${left}px`);
this._setImposterStyle(imposterStyle, 'top', `${top}px`);
}
imposter.scrollTop = element.scrollTop;
imposter.scrollLeft = element.scrollLeft;
return [imposter, container];
}
static _getElementsFromPoint(x, y, all) {
if (all) {
// document.elementsFromPoint can return duplicates which must be removed.
const elements = document.elementsFromPoint(x, y);
return elements.filter((e, i) => elements.indexOf(e) === i);
}
const e = document.elementFromPoint(x, y);
return e !== null ? [e] : [];
}
static _isPointInRange(x, y, range, normalizeCssZoom) {
// Require a text node to start
const {startContainer} = range;
if (startContainer.nodeType !== Node.TEXT_NODE) {
return false;
}
// Convert CSS zoom coordinates
if (normalizeCssZoom) {
const scale = this.computeZoomScale(startContainer);
x /= scale;
y /= scale;
}
// Scan forward
const nodePre = range.endContainer;
const offsetPre = range.endOffset;
try {
const {node, offset, content} = new DOMTextScanner(nodePre, offsetPre, true, false).seek(1);
range.setEnd(node, offset);
if (!this._isWhitespace(content) && this.isPointInAnyRect(x, y, range.getClientRects())) {
return true;
}
} finally {
range.setEnd(nodePre, offsetPre);
}
// Scan backward
const {node, offset, content} = new DOMTextScanner(startContainer, range.startOffset, true, false).seek(-1);
range.setStart(node, offset);
if (!this._isWhitespace(content) && this.isPointInAnyRect(x, y, range.getClientRects())) {
// This purposefully leaves the starting offset as modified and sets the range length to 0.
range.setEnd(node, offset);
return true;
}
// No match
return false;
}
static _isWhitespace(string) {
return string.trim().length === 0;
}
static _caretRangeFromPoint(x, y) {
if (typeof document.caretRangeFromPoint === 'function') {
// Chrome, Edge
return document.caretRangeFromPoint(x, y);
}
if (typeof document.caretPositionFromPoint === 'function') {
// Firefox
return this._caretPositionFromPoint(x, y);
}
// No support
return null;
}
static _caretPositionFromPoint(x, y) {
const position = document.caretPositionFromPoint(x, y);
if (position === null) {
return null;
}
const node = position.offsetNode;
if (node === null) {
return null;
}
let offset = 0;
const {nodeType} = node;
switch (nodeType) {
case Node.TEXT_NODE:
offset = position.offset;
break;
case Node.ELEMENT_NODE:
// Elements with user-select: all will return the element
// instead of a text point inside the element.
if (this._isElementUserSelectAll(node)) {
return this._caretPositionFromPointNormalizeStyles(x, y, node);
}
break;
}
try {
const range = document.createRange();
range.setStart(node, offset);
range.setEnd(node, offset);
return range;
} catch (e) {
// Firefox throws new DOMException("The operation is insecure.")
// when trying to select a node from within a ShadowRoot.
return null;
}
}
static _caretPositionFromPointNormalizeStyles(x, y, nextElement) {
const previousStyles = new Map();
try {
while (true) {
this._recordPreviousStyle(previousStyles, nextElement);
nextElement.style.setProperty('user-select', 'text', 'important');
const position = document.caretPositionFromPoint(x, y);
if (position === null) {
return null;
}
const node = position.offsetNode;
if (node === null) {
return null;
}
let offset = 0;
const {nodeType} = node;
switch (nodeType) {
case Node.TEXT_NODE:
offset = position.offset;
break;
case Node.ELEMENT_NODE:
// Elements with user-select: all will return the element
// instead of a text point inside the element.
if (this._isElementUserSelectAll(node)) {
if (previousStyles.has(node)) {
// Recursive
return null;
}
nextElement = node;
continue;
}
break;
}
try {
const range = document.createRange();
range.setStart(node, offset);
range.setEnd(node, offset);
return range;
} catch (e) {
// Firefox throws new DOMException("The operation is insecure.")
// when trying to select a node from within a ShadowRoot.
return null;
}
}
} finally {
this._revertStyles(previousStyles);
}
}
static _caretRangeFromPointExt(x, y, elements, normalizeCssZoom) {
let previousStyles = null;
try {
let i = 0;
let startContinerPre = null;
while (true) {
const range = this._caretRangeFromPoint(x, y);
if (range === null) {
return null;
}
const startContainer = range.startContainer;
if (startContinerPre !== startContainer) {
if (this._isPointInRange(x, y, range, normalizeCssZoom)) {
return range;
}
startContinerPre = startContainer;
}
if (previousStyles === null) { previousStyles = new Map(); }
i = this._disableTransparentElement(elements, i, previousStyles);
if (i < 0) {
return null;
}
}
} finally {
if (previousStyles !== null && previousStyles.size > 0) {
this._revertStyles(previousStyles);
}
}
}
static _disableTransparentElement(elements, i, previousStyles) {
while (true) {
if (i >= elements.length) {
return -1;
}
const element = elements[i++];
if (this._isElementTransparent(element)) {
this._recordPreviousStyle(previousStyles, element);
element.style.setProperty('pointer-events', 'none', 'important');
return i;
}
}
}
static _recordPreviousStyle(previousStyles, element) {
if (previousStyles.has(element)) { return; }
const style = element.hasAttribute('style') ? element.getAttribute('style') : null;
previousStyles.set(element, style);
}
static _revertStyles(previousStyles) {
for (const [element, style] of previousStyles.entries()) {
if (style === null) {
element.removeAttribute('style');
} else {
element.setAttribute('style', style);
}
}
}
static _isElementTransparent(element) {
if (
element === document.body ||
element === document.documentElement
) {
return false;
}
const style = window.getComputedStyle(element);
return (
parseFloat(style.opacity) <= 0 ||
style.visibility === 'hidden' ||
(style.backgroundImage === 'none' && this._isColorTransparent(style.backgroundColor))
);
}
static _isColorTransparent(cssColor) {
return this._transparentColorPattern.test(cssColor);
}
static _isElementUserSelectAll(element) {
return getComputedStyle(element).userSelect === 'all';
}
static _convertToNumberOrNull(value) {
if (typeof value !== 'number') {
if (typeof value !== 'string' || value.length === 0) {
return null;
}
value = parseFloat(value);
}
return !Number.isNaN(value) ? value : null;
}
}
// eslint-disable-next-line no-underscore-dangle
DocumentUtil._transparentColorPattern = /rgba\s*\([^)]*,\s*0(?:\.0+)?\s*\)/;
// eslint-disable-next-line no-underscore-dangle
DocumentUtil._cssZoomSupported = null;
// eslint-disable-next-line no-underscore-dangle
DocumentUtil._getRangeFromPointHandlers = [];