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-rw-r--r--ext/fg/js/source.js236
1 files changed, 236 insertions, 0 deletions
diff --git a/ext/fg/js/source.js b/ext/fg/js/source.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 TextSourceRange {
+ constructor(range, content='') {
+ this.range = range;
+ this.content = content;
+ }
+
+ clone() {
+ return new TextSourceRange(this.range.cloneRange(), this.content);
+ }
+
+ text() {
+ return this.content;
+ }
+
+ setEndOffset(length) {
+ const state = TextSourceRange.seekForward(this.range.startContainer, this.range.startOffset, length);
+ this.range.setEnd(state.node, state.offset);
+ this.content = state.content;
+ return length - state.remainder;
+ }
+
+ setStartOffset(length) {
+ const state = TextSourceRange.seekBackward(this.range.startContainer, this.range.startOffset, length);
+ this.range.setStart(state.node, state.offset);
+ this.content = state.content;
+ return length - state.remainder;
+ }
+
+ containsPoint(point) {
+ const rect = this.getPaddedRect();
+ return point.x >= rect.left && point.x <= rect.right;
+ }
+
+ getRect() {
+ return this.range.getBoundingClientRect();
+ }
+
+ getPaddedRect() {
+ const range = this.range.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.range);
+ }
+
+ deselect() {
+ const selection = window.getSelection();
+ selection.removeAllRanges();
+ }
+
+ equals(other) {
+ return other.range && other.range.compareBoundaryPoints(Range.START_TO_START, this.range) === 0;
+ }
+
+ static shouldEnter(node) {
+ if (node.nodeType !== 1) {
+ return false;
+ }
+
+ const skip = ['RT', 'SCRIPT', 'STYLE'];
+ if (skip.includes(node.nodeName)) {
+ return false;
+ }
+
+ const style = window.getComputedStyle(node);
+ const hidden =
+ style.visibility === 'hidden' ||
+ style.display === 'none' ||
+ parseFloat(style.fontSize) === 0;
+
+ return !hidden;
+ }
+
+ static seekForward(node, offset, length) {
+ const state = {node, offset, remainder: length, content: ''};
+ if (!TextSourceRange.seekForwardHelper(node, state)) {
+ return state;
+ }
+
+ for (let current = node; current !== null; current = current.parentElement) {
+ for (let sibling = current.nextSibling; sibling !== null; sibling = sibling.nextSibling) {
+ if (!TextSourceRange.seekForwardHelper(sibling, state)) {
+ return state;
+ }
+ }
+ }
+
+ return state;
+ }
+
+ static seekForwardHelper(node, state) {
+ if (node.nodeType === 3 && node.parentElement && TextSourceRange.shouldEnter(node.parentElement)) {
+ const offset = state.node === node ? state.offset : 0;
+ const remaining = node.length - offset;
+ const consumed = Math.min(remaining, state.remainder);
+ state.content = state.content + node.nodeValue.substring(offset, offset + consumed);
+ state.node = node;
+ state.offset = offset + consumed;
+ state.remainder -= consumed;
+ } else if (TextSourceRange.shouldEnter(node)) {
+ for (let i = 0; i < node.childNodes.length; ++i) {
+ if (!TextSourceRange.seekForwardHelper(node.childNodes[i], state)) {
+ break;
+ }
+ }
+ }
+
+ return state.remainder > 0;
+ }
+
+ static seekBackward(node, offset, length) {
+ const state = {node, offset, remainder: length, content: ''};
+ if (!TextSourceRange.seekBackwardHelper(node, state)) {
+ return state;
+ }
+
+ for (let current = node; current !== null; current = current.parentElement) {
+ for (let sibling = current.previousSibling; sibling !== null; sibling = sibling.previousSibling) {
+ if (!TextSourceRange.seekBackwardHelper(sibling, state)) {
+ return state;
+ }
+ }
+ }
+
+ return state;
+ }
+
+ static seekBackwardHelper(node, state) {
+ if (node.nodeType === 3 && node.parentElement && TextSourceRange.shouldEnter(node.parentElement)) {
+ const offset = state.node === node ? state.offset : node.length;
+ const remaining = offset;
+ const consumed = Math.min(remaining, state.remainder);
+ state.content = node.nodeValue.substring(offset - consumed, offset) + state.content;
+ state.node = node;
+ state.offset = offset - consumed;
+ state.remainder -= consumed;
+ } else if (TextSourceRange.shouldEnter(node)) {
+ for (let i = node.childNodes.length - 1; i >= 0; --i) {
+ if (!TextSourceRange.seekBackwardHelper(node.childNodes[i], state)) {
+ break;
+ }
+ }
+ }
+
+ return state.remainder > 0;
+ }
+}
+
+
+class TextSourceElement {
+ constructor(element, content='') {
+ this.element = element;
+ this.content = content;
+ }
+
+ clone() {
+ return new TextSourceElement(this.element, this.content);
+ }
+
+ text() {
+ return this.content;
+ }
+
+ setEndOffset(length) {
+ switch (this.element.nodeName) {
+ case 'BUTTON':
+ this.content = this.element.innerHTML;
+ break;
+ case 'IMG':
+ this.content = this.element.getAttribute('alt');
+ break;
+ default:
+ this.content = this.element.value;
+ break;
+ }
+
+ this.content = this.content || '';
+ this.content = this.content.substring(0, length);
+
+ return this.content.length;
+ }
+
+ setStartOffset(length) {
+ return 0;
+ }
+
+ containsPoint(point) {
+ const rect = this.getRect();
+ return point.x >= rect.left && point.x <= rect.right;
+ }
+
+ getRect() {
+ return this.element.getBoundingClientRect();
+ }
+
+ select() {
+ // NOP
+ }
+
+ deselect() {
+ // NOP
+ }
+
+ equals(other) {
+ return other.element === this.element && other.content === this.content;
+ }
+}