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-rw-r--r--ext/fg/js/source-range.js113
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diff --git a/ext/fg/js/source-range.js b/ext/fg/js/source-range.js
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+/*
+ * Copyright (C) 2016 Alex Yatskov <alex@foosoft.net>
+ * Author: Alex Yatskov <alex@foosoft.net>
+ *
+ * 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 <http://www.gnu.org/licenses/>.
+ */
+
+
+class Range {
+ constructor(range) {
+ this.rng = range;
+ }
+
+ text() {
+ return this.rng.toString();
+ }
+
+ setLength(length) {
+ const end = Range.seekEnd(this.rng.startContainer, this.rng.startOffset + length);
+ this.rng.setEnd(end.node, end.offset);
+ }
+
+ containsPoint(point) {
+ const rect = this.getPaddedRect();
+ return point.x >= rect.left && point.x <= rect.right;
+ }
+
+ getRect() {
+ return this.rng.getBoundingClientRect();
+ }
+
+ getPaddedRect() {
+ const range = this.rng.cloneRange();
+ const startOffset = range.startOffset;
+ const endOffset = range.endOffset;
+ const node = range.startContainer;
+
+ range.setStart(node, Math.max(0, startOffset - 1));
+ range.setEnd(node, Math.min(node.length, endOffset + 1));
+
+ return range.getBoundingClientRect();
+ }
+
+ select() {
+ const selection = window.getSelection();
+ selection.removeAllRanges();
+ selection.addRange(this.rng);
+ }
+
+ deselect() {
+ const selection = window.getSelection();
+ selection.removeAllRanges();
+ }
+
+ compareOrigin(range) {
+ return range.rng.compareBoundaryPoints(Range.START_TO_START, this.rng);
+ }
+
+ static seekEnd(node, length) {
+ const state = {node, offset: 0, length};
+
+ if (!Range.seekEndRecurse(node, state)) {
+ return {node: state.node, offset: state.offset};
+ }
+
+ for (let sibling = node.nextSibling; sibling !== null; sibling = sibling.nextSibling) {
+ if (!Range.seekEndRecurse(sibling, state)) {
+ return {node: state.node, offset: state.offset};
+ }
+ }
+
+ for (let sibling = node.parentElement.nextSibling; sibling !== null; sibling = sibling.nextSibling) {
+ if (!Range.seekEndRecurse(sibling, state)) {
+ return {node: state.node, offset: state.offset};
+ }
+ }
+
+ return {node: state.node, offset: state.offset};
+ }
+
+ static seekEndRecurse(node, state) {
+ if (node.nodeType === 3) {
+ const consumed = Math.min(node.length, state.length);
+ state.node = node;
+ state.offset = consumed;
+ state.length -= consumed;
+ } else {
+ for (let i = 0; i < node.childNodes.length; ++i) {
+ if (!Range.seekEndRecurse(node.childNodes[i], state)) {
+ break;
+ }
+ }
+ }
+
+ return state.length > 0;
+ }
+
+ static fromPoint(point) {
+ const range = document.caretRangeFromPoint(point.x, point.y);
+ return range === null ? null : new Range(range);
+ }
+}