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+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/**
+ * @fileoverview A collection of JavaScript utilities used to improve selection
+ * at different granularities.
+ */
+
+
+goog.provide('cvox.SelectionUtil');
+
+goog.require('cvox.DomUtil');
+goog.require('cvox.XpathUtil');
+
+/**
+ * Utilities for improving selection.
+ * @constructor
+ */
+cvox.SelectionUtil = function() {};
+
+/**
+ * Cleans up a paragraph selection acquired by extending forward.
+ * In this context, a paragraph selection is 'clean' when the focus
+ * node (the end of the selection) is not on a text node.
+ * @param {Selection} sel The paragraph-length selection.
+ * @return {boolean} True if the selection has been cleaned.
+ * False if the selection cannot be cleaned without invalid extension.
+ */
+cvox.SelectionUtil.cleanUpParagraphForward = function(sel) {
+ var expand = true;
+
+ // nodeType:3 == TEXT_NODE
+ while (sel.focusNode.nodeType == 3) {
+ // Ending with a text node, which is incorrect. Keep extending forward.
+ var fnode = sel.focusNode;
+ var foffset = sel.focusOffset;
+
+ sel.modify('extend', 'forward', 'sentence');
+ if ((fnode == sel.focusNode) && (foffset == sel.focusOffset)) {
+ // Nothing more to be done, cannot extend forward further.
+ return false;
+ }
+ }
+
+ return true;
+};
+
+/**
+ * Cleans up a paragraph selection acquired by extending backward.
+ * In this context, a paragraph selection is 'clean' when the focus
+ * node (the end of the selection) is not on a text node.
+ * @param {Selection} sel The paragraph-length selection.
+ * @return {boolean} True if the selection has been cleaned.
+ * False if the selection cannot be cleaned without invalid extension.
+ */
+cvox.SelectionUtil.cleanUpParagraphBack = function(sel) {
+ var expand = true;
+
+ var fnode;
+ var foffset;
+
+ // nodeType:3 == TEXT_NODE
+ while (sel.focusNode.nodeType == 3) {
+ // Ending with a text node, which is incorrect. Keep extending backward.
+ fnode = sel.focusNode;
+ foffset = sel.focusOffset;
+
+ sel.modify('extend', 'backward', 'sentence');
+
+ if ((fnode == sel.focusNode) && (foffset == sel.focusOffset)) {
+ // Nothing more to be done, cannot extend backward further.
+ return true;
+ }
+ }
+
+ return true;
+};
+
+/**
+ * Cleans up a sentence selection by extending forward.
+ * In this context, a sentence selection is 'clean' when the focus
+ * node (the end of the selection) is either:
+ * - not on a text node
+ * - on a text node that ends with a period or a space
+ * @param {Selection} sel The sentence-length selection.
+ * @return {boolean} True if the selection has been cleaned.
+ * False if the selection cannot be cleaned without invalid extension.
+ */
+cvox.SelectionUtil.cleanUpSentence = function(sel) {
+ var expand = true;
+ var lastSelection;
+ var lastSelectionOffset;
+
+ while (expand) {
+
+ // nodeType:3 == TEXT_NODE
+ if (sel.focusNode.nodeType == 3) {
+ // The focus node is of type text, check end for period
+
+ var fnode = sel.focusNode;
+ var foffset = sel.focusOffset;
+
+ if (sel.rangeCount > 0 && sel.getRangeAt(0).endOffset > 0) {
+ if (fnode.substringData(sel.getRangeAt(0).endOffset - 1, 1) == '.') {
+ // Text node ends with period.
+ return true;
+ } else if (fnode.substringData(sel.getRangeAt(0).endOffset - 1, 1) ==
+ ' ') {
+ // Text node ends with space.
+ return true;
+ } else {
+ // Text node does not end with period or space. Extend forward.
+ sel.modify('extend', 'forward', 'sentence');
+
+ if ((fnode == sel.focusNode) && (foffset == sel.focusOffset)) {
+ // Nothing more to be done, cannot extend forward any further.
+ return false;
+ }
+ }
+ } else {
+ return true;
+ }
+ } else {
+ // Focus node is not text node, no further cleaning required.
+ return true;
+ }
+ }
+
+ return true;
+};
+
+/**
+ * Finds the starting position (height from top and left width) of a
+ * selection in a document.
+ * @param {Selection} sel The selection.
+ * @return {Array} The coordinates [top, left] of the selection.
+ */
+cvox.SelectionUtil.findSelPosition = function(sel) {
+ if (sel.rangeCount == 0) {
+ return [0, 0];
+ }
+
+ var clientRect = sel.getRangeAt(0).getBoundingClientRect();
+
+ if (!clientRect) {
+ return [0, 0];
+ }
+
+ var top = window.pageYOffset + clientRect.top;
+ var left = window.pageXOffset + clientRect.left;
+ return [top, left];
+};
+
+/**
+ * Calculates the horizontal and vertical position of a node
+ * @param {Node} targetNode The node.
+ * @return {Array} The coordinates [top, left] of the node.
+ */
+cvox.SelectionUtil.findTopLeftPosition = function(targetNode) {
+ var left = 0;
+ var top = 0;
+ var obj = targetNode;
+
+ if (obj.offsetParent) {
+ left = obj.offsetLeft;
+ top = obj.offsetTop;
+ obj = obj.offsetParent;
+
+ while (obj !== null) {
+ left += obj.offsetLeft;
+ top += obj.offsetTop;
+ obj = obj.offsetParent;
+ }
+ }
+
+ return [top, left];
+};
+
+
+/**
+ * Checks the contents of a selection for meaningful content.
+ * @param {Selection} sel The selection.
+ * @return {boolean} True if the selection is valid. False if the selection
+ * contains only whitespace or is an empty string.
+ */
+cvox.SelectionUtil.isSelectionValid = function(sel) {
+ var regExpWhiteSpace = new RegExp(/^\s+$/);
+ return (! ((regExpWhiteSpace.test(sel.toString())) ||
+ (sel.toString() == '')));
+};
+
+/**
+ * Checks the contents of a range for meaningful content.
+ * @param {Range} range The range.
+ * @return {boolean} True if the range is valid. False if the range
+ * contains only whitespace or is an empty string.
+ */
+cvox.SelectionUtil.isRangeValid = function(range) {
+ var text = range.cloneContents().textContent;
+ var regExpWhiteSpace = new RegExp(/^\s+$/);
+ return (! ((regExpWhiteSpace.test(text)) ||
+ (text == '')));
+};
+
+/**
+ * Returns absolute top and left positions of an element.
+ *
+ * @param {!Node} node The element for which to compute the position.
+ * @return {Array.<number>} Index 0 is the left; index 1 is the top.
+ * @private
+ */
+cvox.SelectionUtil.findPos_ = function(node) {
+ var curLeft = 0;
+ var curTop = 0;
+ if (node.offsetParent) {
+ do {
+ curLeft += node.offsetLeft;
+ curTop += node.offsetTop;
+ } while (node = node.offsetParent);
+ }
+ return [curLeft, curTop];
+};
+
+/**
+ * Scrolls node in its parent node such the given node is visible.
+ * @param {Node} focusNode The node.
+ */
+cvox.SelectionUtil.scrollElementsToView = function(focusNode) {
+ // First, walk up the DOM until we find a node with a bounding rectangle.
+ while (focusNode && !focusNode.getBoundingClientRect) {
+ focusNode = focusNode.parentElement;
+ }
+ if (!focusNode) {
+ return;
+ }
+
+ // Walk up the DOM, ensuring each element is visible inside its parent.
+ var node = focusNode;
+ var parentNode = node.parentElement;
+ while (node != document.body && parentNode) {
+ node.scrollTop = node.offsetTop;
+ node.scrollLeft = node.offsetLeft;
+ node = parentNode;
+ parentNode = node.parentElement;
+ }
+
+ // Center the active element on the page once we know it's visible.
+ var pos = cvox.SelectionUtil.findPos_(focusNode);
+ window.scrollTo(pos[0] - window.innerWidth / 2,
+ pos[1] - window.innerHeight / 2);
+};
+
+/**
+ * Scrolls the selection into view if it is out of view in the current window.
+ * Inspired by workaround for already-on-screen elements @
+ * http://
+ * www.performantdesign.com/2009/08/26/scrollintoview-but-only-if-out-of-view/
+ * @param {Selection} sel The selection to be scrolled into view.
+ */
+cvox.SelectionUtil.scrollToSelection = function(sel) {
+ if (sel.rangeCount == 0) {
+ return;
+ }
+
+ // First, scroll all parent elements into view. Later, move the body
+ // which works slightly differently.
+
+ cvox.SelectionUtil.scrollElementsToView(sel.focusNode);
+
+ var pos = cvox.SelectionUtil.findSelPosition(sel);
+ var top = pos[0];
+ var left = pos[1];
+
+ var scrolledVertically = window.pageYOffset ||
+ document.documentElement.scrollTop ||
+ document.body.scrollTop;
+ var pageHeight = window.innerHeight ||
+ document.documentElement.clientHeight || document.body.clientHeight;
+ var pageWidth = window.innerWidth ||
+ document.documentElement.innerWidth || document.body.clientWidth;
+
+ if (left < pageWidth) {
+ left = 0;
+ }
+
+ // window.scroll puts specified pixel in upper left of window
+ if ((scrolledVertically + pageHeight) < top) {
+ // Align with bottom of page
+ var diff = top - pageHeight;
+ window.scroll(left, diff + 100);
+ } else if (top < scrolledVertically) {
+ // Align with top of page
+ window.scroll(left, top - 100);
+ }
+};
+
+/**
+ * This is from https://developer.mozilla.org/en/Whitespace_in_the_DOM
+ * Determine whether a node's text content is entirely whitespace.
+ *
+ * Throughout, whitespace is defined as one of the characters
+ * "\t" TAB \u0009
+ * "\n" LF \u000A
+ * "\r" CR \u000D
+ * " " SPC \u0020
+ *
+ * This does not use Javascript's "\s" because that includes non-breaking
+ * spaces (and also some other characters).
+ *
+ * @param {Node} node A node implementing the |CharacterData| interface (i.e.,
+ * a |Text|, |Comment|, or |CDATASection| node.
+ * @return {boolean} True if all of the text content of |node| is whitespace,
+ * otherwise false.
+ */
+cvox.SelectionUtil.isAllWs = function(node) {
+ // Use ECMA-262 Edition 3 String and RegExp features
+ return !(/[^\t\n\r ]/.test(node.data));
+};
+
+
+/**
+ * This is from https://developer.mozilla.org/en/Whitespace_in_the_DOM
+ * Determine if a node should be ignored by the iterator functions.
+ *
+ * @param {Node} node An object implementing the DOM1 |Node| interface.
+ * @return {boolean} True if the node is:
+ * 1) A |Text| node that is all whitespace
+ * 2) A |Comment| node
+ * and otherwise false.
+ */
+
+cvox.SelectionUtil.isIgnorable = function(node) {
+ return (node.nodeType == 8) || // A comment node
+ ((node.nodeType == 3) &&
+ cvox.SelectionUtil.isAllWs(node)); // a text node, all ws
+};
+
+/**
+ * This is from https://developer.mozilla.org/en/Whitespace_in_the_DOM
+ * Version of |previousSibling| that skips nodes that are entirely
+ * whitespace or comments. (Normally |previousSibling| is a property
+ * of all DOM nodes that gives the sibling node, the node that is
+ * a child of the same parent, that occurs immediately before the
+ * reference node.)
+ *
+ * @param {Node} sib The reference node.
+ * @return {Node} Either:
+ * 1) The closest previous sibling to |sib| that is not
+ * ignorable according to |isIgnorable|, or
+ * 2) null if no such node exists.
+ */
+cvox.SelectionUtil.nodeBefore = function(sib) {
+ while ((sib = sib.previousSibling)) {
+ if (!cvox.SelectionUtil.isIgnorable(sib)) {
+ return sib;
+ }
+ }
+ return null;
+};
+
+/**
+ * This is from https://developer.mozilla.org/en/Whitespace_in_the_DOM
+ * Version of |nextSibling| that skips nodes that are entirely
+ * whitespace or comments.
+ *
+ * @param {Node} sib The reference node.
+ * @return {Node} Either:
+ * 1) The closest next sibling to |sib| that is not
+ * ignorable according to |isIgnorable|, or
+ * 2) null if no such node exists.
+ */
+cvox.SelectionUtil.nodeAfter = function(sib) {
+ while ((sib = sib.nextSibling)) {
+ if (!cvox.SelectionUtil.isIgnorable(sib)) {
+ return sib;
+ }
+ }
+ return null;
+};
+
+/**
+ * This is from https://developer.mozilla.org/en/Whitespace_in_the_DOM
+ * Version of |lastChild| that skips nodes that are entirely
+ * whitespace or comments. (Normally |lastChild| is a property
+ * of all DOM nodes that gives the last of the nodes contained
+ * directly in the reference node.)
+ *
+ * @param {Node} par The reference node.
+ * @return {Node} Either:
+ * 1) The last child of |sib| that is not
+ * ignorable according to |isIgnorable|, or
+ * 2) null if no such node exists.
+ */
+cvox.SelectionUtil.lastChildNode = function(par) {
+ var res = par.lastChild;
+ while (res) {
+ if (!cvox.SelectionUtil.isIgnorable(res)) {
+ return res;
+ }
+ res = res.previousSibling;
+ }
+ return null;
+};
+
+/**
+ * This is from https://developer.mozilla.org/en/Whitespace_in_the_DOM
+ * Version of |firstChild| that skips nodes that are entirely
+ * whitespace and comments.
+ *
+ * @param {Node} par The reference node.
+ * @return {Node} Either:
+ * 1) The first child of |sib| that is not
+ * ignorable according to |isIgnorable|, or
+ * 2) null if no such node exists.
+ */
+cvox.SelectionUtil.firstChildNode = function(par) {
+ var res = par.firstChild;
+ while (res) {
+ if (!cvox.SelectionUtil.isIgnorable(res)) {
+ return res;
+ }
+ res = res.nextSibling;
+ }
+ return null;
+};
+
+/**
+ * This is from https://developer.mozilla.org/en/Whitespace_in_the_DOM
+ * Version of |data| that doesn't include whitespace at the beginning
+ * and end and normalizes all whitespace to a single space. (Normally
+ * |data| is a property of text nodes that gives the text of the node.)
+ *
+ * @param {Node} txt The text node whose data should be returned.
+ * @return {string} A string giving the contents of the text node with
+ * whitespace collapsed.
+ */
+cvox.SelectionUtil.dataOf = function(txt) {
+ var data = txt.data;
+ // Use ECMA-262 Edition 3 String and RegExp features
+ data = data.replace(/[\t\n\r ]+/g, ' ');
+ if (data.charAt(0) == ' ') {
+ data = data.substring(1, data.length);
+ }
+ if (data.charAt(data.length - 1) == ' ') {
+ data = data.substring(0, data.length - 1);
+ }
+ return data;
+};
+
+/**
+ * Returns true if the selection has content from at least one node
+ * that has the specified tagName.
+ *
+ * @param {Selection} sel The selection.
+ * @param {string} tagName Tagname that the selection should be checked for.
+ * @return {boolean} True if the selection has content from at least one node
+ * with the specified tagName.
+ */
+cvox.SelectionUtil.hasContentWithTag = function(sel, tagName) {
+ if (!sel || !sel.anchorNode || !sel.focusNode) {
+ return false;
+ }
+ if (sel.anchorNode.tagName && (sel.anchorNode.tagName == tagName)) {
+ return true;
+ }
+ if (sel.focusNode.tagName && (sel.focusNode.tagName == tagName)) {
+ return true;
+ }
+ if (sel.anchorNode.parentNode.tagName &&
+ (sel.anchorNode.parentNode.tagName == tagName)) {
+ return true;
+ }
+ if (sel.focusNode.parentNode.tagName &&
+ (sel.focusNode.parentNode.tagName == tagName)) {
+ return true;
+ }
+ var docFrag = sel.getRangeAt(0).cloneContents();
+ var span = document.createElement('span');
+ span.appendChild(docFrag);
+ return (span.getElementsByTagName(tagName).length > 0);
+};
+
+/**
+ * Selects text within a text node.
+ *
+ * Note that the input node MUST be of type TEXT; otherwise, the offset
+ * count would not mean # of characters - this is because of the way Range
+ * works in JavaScript.
+ *
+ * @param {Node} textNode The text node to select text within.
+ * @param {number} start The start of the selection.
+ * @param {number} end The end of the selection.
+ */
+cvox.SelectionUtil.selectText = function(textNode, start, end) {
+ var newRange = document.createRange();
+ newRange.setStart(textNode, start);
+ newRange.setEnd(textNode, end);
+ var sel = window.getSelection();
+ sel.removeAllRanges();
+ sel.addRange(newRange);
+};
+
+/**
+ * Selects all the text in a given node.
+ *
+ * @param {Node} node The target node.
+ */
+cvox.SelectionUtil.selectAllTextInNode = function(node) {
+ var newRange = document.createRange();
+ newRange.setStart(node, 0);
+ newRange.setEndAfter(node);
+ var sel = window.getSelection();
+ sel.removeAllRanges();
+ sel.addRange(newRange);
+};
+
+/**
+ * Collapses the selection to the start. If nothing is selected,
+ * selects the beginning of the given node.
+ *
+ * @param {Node} node The target node.
+ */
+cvox.SelectionUtil.collapseToStart = function(node) {
+ var sel = window.getSelection();
+ var cursorNode = sel.anchorNode;
+ var cursorOffset = sel.anchorOffset;
+ if (cursorNode == null) {
+ cursorNode = node;
+ cursorOffset = 0;
+ }
+ var newRange = document.createRange();
+ newRange.setStart(cursorNode, cursorOffset);
+ newRange.setEnd(cursorNode, cursorOffset);
+ sel.removeAllRanges();
+ sel.addRange(newRange);
+};
+
+/**
+ * Collapses the selection to the end. If nothing is selected,
+ * selects the end of the given node.
+ *
+ * @param {Node} node The target node.
+ */
+cvox.SelectionUtil.collapseToEnd = function(node) {
+ var sel = window.getSelection();
+ var cursorNode = sel.focusNode;
+ var cursorOffset = sel.focusOffset;
+ if (cursorNode == null) {
+ cursorNode = node;
+ cursorOffset = 0;
+ }
+ var newRange = document.createRange();
+ newRange.setStart(cursorNode, cursorOffset);
+ newRange.setEnd(cursorNode, cursorOffset);
+ sel.removeAllRanges();
+ sel.addRange(newRange);
+};
+
+/**
+ * Retrieves all the text within a selection.
+ *
+ * Note that this can be different than simply using the string from
+ * window.getSelection() as this will account for IMG nodes, etc.
+ *
+ * @return {string} The string of text contained in the current selection.
+ */
+cvox.SelectionUtil.getText = function() {
+ var sel = window.getSelection();
+ if (cvox.SelectionUtil.hasContentWithTag(sel, 'IMG')) {
+ var text = '';
+ var docFrag = sel.getRangeAt(0).cloneContents();
+ var span = document.createElement('span');
+ span.appendChild(docFrag);
+ var leafNodes = cvox.XpathUtil.getLeafNodes(span);
+ for (var i = 0, node; node = leafNodes[i]; i++) {
+ text = text + ' ' + cvox.DomUtil.getName(node);
+ }
+ return text;
+ } else {
+ return this.getSelectionText_();
+ }
+};
+
+/**
+ * Returns the selection as text instead of a selection object. Note that this
+ * function must be used in place of getting text directly from the DOM
+ * if you want i18n tests to pass.
+ *
+ * @return {string} The text.
+ */
+cvox.SelectionUtil.getSelectionText_ = function() {
+ return '' + window.getSelection();
+};
+
+
+/**
+ * Returns a range as text instead of a selection object. Note that this
+ * function must be used in place of getting text directly from the DOM
+ * if you want i18n tests to pass.
+ *
+ * @param {Range} range A range.
+ * @return {string} The text.
+ */
+cvox.SelectionUtil.getRangeText = function(range) {
+ if (range)
+ return range.cloneContents().textContent.replace(/\s+/g, ' ');
+ else
+ return '';
+};