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// Copyright (C) 2016 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the 'License');
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an 'AS IS' BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
(function(window) {
'use strict';
// Prevent redefinition.
if (window.GrRangeNormalizer) { return; }
// Astral code point as per https://mathiasbynens.be/notes/javascript-unicode
var REGEX_ASTRAL_SYMBOL = /[\uD800-\uDBFF][\uDC00-\uDFFF]/;
var GrRangeNormalizer = {
/**
* Remap DOM range to whole lines of a diff if necessary. If the start or
* end containers are DOM elements that are singular pieces of syntax
* highlighting, the containers are remapped to the .contentText divs that
* contain the entire line of code.
*
* @param {Object} range - the standard DOM selector range.
* @return {Object} A modified version of the range that correctly accounts
* for syntax highlighting.
*/
normalize: function(range) {
var startContainer = this._getContentTextParent(range.startContainer);
var startOffset = range.startOffset + this._getTextOffset(startContainer,
range.startContainer);
var endContainer = this._getContentTextParent(range.endContainer);
var endOffset = range.endOffset + this._getTextOffset(endContainer,
range.endContainer);
return {
startContainer: startContainer,
startOffset: startOffset,
endContainer: endContainer,
endOffset: endOffset,
};
},
_getContentTextParent: function(target) {
var element = target;
if (element.nodeName === '#text') {
element = element.parentElement;
}
while (!element.classList.contains('contentText')) {
if (element.parentElement === null) {
return target;
}
element = element.parentElement;
}
return element;
},
/**
* Gets the character offset of the child within the parent.
* Performs a synchronous in-order traversal from top to bottom of the node
* element, counting the length of the syntax until child is found.
*
* @param {!Element} node The root DOM element to be searched through.
* @param {!Element} child The child element being searched for.
* @return {number}
*/
_getTextOffset: function(node, child) {
var count = 0;
var stack = [node];
while (stack.length) {
var n = stack.pop();
if (n === child) {
break;
}
if (n.childNodes && n.childNodes.length !== 0) {
var arr = [];
for (var i = 0; i < n.childNodes.length; i++) {
arr.push(n.childNodes[i]);
}
arr.reverse();
stack = stack.concat(arr);
} else {
count += this._getLength(n);
}
}
return count;
},
/**
* The DOM API textContent.length calculation is broken when the text
* contains Unicode. See https://mathiasbynens.be/notes/javascript-unicode .
* @param {Text} A text node.
* @return {Number} The length of the text.
*/
_getLength: function(node) {
return node.textContent.replace(REGEX_ASTRAL_SYMBOL, '_').length;
},
};
window.GrRangeNormalizer = GrRangeNormalizer;
})(window);
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