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+/*
+ * Copyright (C) 2016-2020 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 <https://www.gnu.org/licenses/>.
+ */
+
+/* global
+ * DOM
+ * DOMTextScanner
+ * TextSourceElement
+ * TextSourceRange
+ */
+
+class DocumentUtil {
+ constructor() {
+ this._transparentColorPattern = /rgba\s*\([^)]*,\s*0(?:\.0+)?\s*\)/;
+ }
+
+ getRangeFromPoint(x, y, deepContentScan) {
+ 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':
+ return new TextSourceElement(element);
+ case 'INPUT':
+ 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 : []);
+ if (range !== null) {
+ if (imposter !== null) {
+ this._setImposterStyle(imposterContainer.style, 'z-index', '-2147483646');
+ this._setImposterStyle(imposter.style, 'pointer-events', 'none');
+ }
+ return new TextSourceRange(range, '', imposterContainer, imposterSourceElement);
+ } else {
+ if (imposterContainer !== null) {
+ imposterContainer.parentNode.removeChild(imposterContainer);
+ }
+ return null;
+ }
+ }
+
+ extractSentence(source, extent, layoutAwareScan) {
+ const quotesFwd = {'「': '」', '『': '』', "'": "'", '"': '"'};
+ const quotesBwd = {'」': '「', '』': '『', "'": "'", '"': '"'};
+ const terminators = '…。..??!!';
+
+ const sourceLocal = source.clone();
+ const position = sourceLocal.setStartOffset(extent, layoutAwareScan);
+ sourceLocal.setEndOffset(extent * 2 - position, layoutAwareScan, true);
+ const content = sourceLocal.text();
+
+ let quoteStack = [];
+
+ let startPos = 0;
+ for (let i = position; i >= startPos; --i) {
+ const c = content[i];
+
+ if (c === '\n') {
+ startPos = i + 1;
+ break;
+ }
+
+ if (quoteStack.length === 0 && (terminators.includes(c) || c in quotesFwd)) {
+ startPos = i + 1;
+ break;
+ }
+
+ if (quoteStack.length > 0 && c === quoteStack[0]) {
+ quoteStack.pop();
+ } else if (c in quotesBwd) {
+ quoteStack.unshift(quotesBwd[c]);
+ }
+ }
+
+ quoteStack = [];
+
+ let endPos = content.length;
+ for (let i = position; i <= endPos; ++i) {
+ const c = content[i];
+
+ if (c === '\n') {
+ endPos = i + 1;
+ break;
+ }
+
+ if (quoteStack.length === 0) {
+ if (terminators.includes(c)) {
+ endPos = i + 1;
+ break;
+ } else if (c in quotesBwd) {
+ endPos = i;
+ break;
+ }
+ }
+
+ if (quoteStack.length > 0 && c === quoteStack[0]) {
+ quoteStack.pop();
+ } else if (c in quotesFwd) {
+ quoteStack.unshift(quotesFwd[c]);
+ }
+ }
+
+ const text = content.substring(startPos, endPos);
+ const padding = text.length - text.replace(/^\s+/, '').length;
+
+ return {
+ text: text.trim(),
+ offset: position - startPos - padding
+ };
+ }
+
+ // Private
+
+ _setImposterStyle(style, propertyName, value) {
+ style.setProperty(propertyName, value, 'important');
+ }
+
+ _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.x !== elementRect.x || imposterRect.y !== elementRect.y) {
+ 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];
+ }
+
+ _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] : [];
+ }
+
+ _isPointInRange(x, y, range) {
+ // Require a text node to start
+ if (range.startContainer.nodeType !== Node.TEXT_NODE) {
+ return false;
+ }
+
+ // Scan forward
+ const nodePre = range.endContainer;
+ const offsetPre = range.endOffset;
+ try {
+ const {node, offset, content} = new DOMTextScanner(range.endContainer, range.endOffset, true, false).seek(1);
+ range.setEnd(node, offset);
+
+ if (!this._isWhitespace(content) && DOM.isPointInAnyRect(x, y, range.getClientRects())) {
+ return true;
+ }
+ } finally {
+ range.setEnd(nodePre, offsetPre);
+ }
+
+ // Scan backward
+ const {node, offset, content} = new DOMTextScanner(range.startContainer, range.startOffset, true, false).seek(-1);
+ range.setStart(node, offset);
+
+ if (!this._isWhitespace(content) && DOM.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;
+ }
+
+ _isWhitespace(string) {
+ return string.trim().length === 0;
+ }
+
+ _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;
+ }
+
+ _caretPositionFromPoint(x, y) {
+ const position = document.caretPositionFromPoint(x, y);
+ if (position === null) {
+ return null;
+ }
+ const node = position.offsetNode;
+ if (node === null) {
+ return null;
+ }
+
+ const range = document.createRange();
+ const offset = (node.nodeType === Node.TEXT_NODE ? position.offset : 0);
+ try {
+ range.setStart(node, offset);
+ range.setEnd(node, offset);
+ } catch (e) {
+ // Firefox throws new DOMException("The operation is insecure.")
+ // when trying to select a node from within a ShadowRoot.
+ return null;
+ }
+ return range;
+ }
+
+ _caretRangeFromPointExt(x, y, elements) {
+ const modifications = [];
+ 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)) {
+ return range;
+ }
+ startContinerPre = startContainer;
+ }
+
+ i = this._disableTransparentElement(elements, i, modifications);
+ if (i < 0) {
+ return null;
+ }
+ }
+ } finally {
+ if (modifications.length > 0) {
+ this._restoreElementStyleModifications(modifications);
+ }
+ }
+ }
+
+ _disableTransparentElement(elements, i, modifications) {
+ while (true) {
+ if (i >= elements.length) {
+ return -1;
+ }
+
+ const element = elements[i++];
+ if (this._isElementTransparent(element)) {
+ const style = element.hasAttribute('style') ? element.getAttribute('style') : null;
+ modifications.push({element, style});
+ element.style.setProperty('pointer-events', 'none', 'important');
+ return i;
+ }
+ }
+ }
+
+ _restoreElementStyleModifications(modifications) {
+ for (const {element, style} of modifications) {
+ if (style === null) {
+ element.removeAttribute('style');
+ } else {
+ element.setAttribute('style', style);
+ }
+ }
+ }
+
+ _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))
+ );
+ }
+
+ _isColorTransparent(cssColor) {
+ return this._transparentColorPattern.test(cssColor);
+ }
+}