Chromium Code Reviews
chromiumcodereview-hr@appspot.gserviceaccount.com (chromiumcodereview-hr) | Please choose your nickname with Settings | Help | Chromium Project | Gerrit Changes | Sign out
(286)

Unified Diff: ui/accessibility/extensions/caretbrowsing/traverse_util.js

Issue 606653005: Revert "Initial checkin of accessibility extensions." (Closed) Base URL: https://chromium.googlesource.com/chromium/src.git@master
Patch Set: Created 6 years, 3 months ago
Use n/p to move between diff chunks; N/P to move between comments. Draft comments are only viewable by you.
Jump to:
View side-by-side diff with in-line comments
Download patch
Index: ui/accessibility/extensions/caretbrowsing/traverse_util.js
diff --git a/ui/accessibility/extensions/caretbrowsing/traverse_util.js b/ui/accessibility/extensions/caretbrowsing/traverse_util.js
deleted file mode 100644
index eca38baffb90bddb41a67f7c73cb4bc141eee3b4..0000000000000000000000000000000000000000
--- a/ui/accessibility/extensions/caretbrowsing/traverse_util.js
+++ /dev/null
@@ -1,879 +0,0 @@
-// Copyright 2014 Google Inc.
-//
-// 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.
-
-/**
- * @fileoverview Low-level DOM traversal utility functions to find the
- * next (or previous) character, word, sentence, line, or paragraph,
- * in a completely stateless manner without actually manipulating the
- * selection.
- */
-
-/**
- * A class to represent a cursor location in the document,
- * like the start position or end position of a selection range.
- *
- * Later this may be extended to support "virtual text" for an object,
- * like the ALT text for an image.
- *
- * Note: we cache the text of a particular node at the time we
- * traverse into it. Later we should add support for dynamically
- * reloading it.
- * @param {Node} node The DOM node.
- * @param {number} index The index of the character within the node.
- * @param {string} text The cached text contents of the node.
- * @constructor
- */
-Cursor = function(node, index, text) {
- this.node = node;
- this.index = index;
- this.text = text;
-};
-
-/**
- * @return {Cursor} A new cursor pointing to the same location.
- */
-Cursor.prototype.clone = function() {
- return new Cursor(this.node, this.index, this.text);
-};
-
-/**
- * Modify this cursor to point to the location that another cursor points to.
- * @param {Cursor} otherCursor The cursor to copy from.
- */
-Cursor.prototype.copyFrom = function(otherCursor) {
- this.node = otherCursor.node;
- this.index = otherCursor.index;
- this.text = otherCursor.text;
-};
-
-/**
- * Utility functions for stateless DOM traversal.
- * @constructor
- */
-TraverseUtil = function() {};
-
-/**
- * Gets the text representation of a node. This allows us to substitute
- * alt text, names, or titles for html elements that provide them.
- * @param {Node} node A DOM node.
- * @return {string} A text string representation of the node.
- */
-TraverseUtil.getNodeText = function(node) {
- if (node.constructor == Text) {
- return node.data;
- } else {
- return '';
- }
-};
-
-/**
- * Return true if a node should be treated as a leaf node, because
- * its children are properties of the object that shouldn't be traversed.
- *
- * TODO(dmazzoni): replace this with a predicate that detects nodes with
- * ARIA roles and other objects that have their own description.
- * For now we just detect a couple of common cases.
- *
- * @param {Node} node A DOM node.
- * @return {boolean} True if the node should be treated as a leaf node.
- */
-TraverseUtil.treatAsLeafNode = function(node) {
- return node.childNodes.length == 0 ||
- node.nodeName == 'SELECT' ||
- node.nodeName == 'OBJECT';
-};
-
-/**
- * Return true only if a single character is whitespace.
- * From https://developer.mozilla.org/en/Whitespace_in_the_DOM,
- * whitespace is defined as one of the characters
- * "\t" TAB \u0009
- * "\n" LF \u000A
- * "\r" CR \u000D
- * " " SPC \u0020.
- *
- * @param {string} c A string containing a single character.
- * @return {boolean} True if the character is whitespace, otherwise false.
- */
-TraverseUtil.isWhitespace = function(c) {
- return (c == ' ' || c == '\n' || c == '\r' || c == '\t');
-};
-
-/**
- * Set the selection to the range between the given start and end cursors.
- * @param {Cursor} start The desired start of the selection.
- * @param {Cursor} end The desired end of the selection.
- * @return {Selection} the selection object.
- */
-TraverseUtil.setSelection = function(start, end) {
- var sel = window.getSelection();
- sel.removeAllRanges();
- var range = document.createRange();
- range.setStart(start.node, start.index);
- range.setEnd(end.node, end.index);
- sel.addRange(range);
-
- return sel;
-};
-
-/**
- * Use the computed CSS style to figure out if this DOM node is currently
- * visible.
- * @param {Node} node A HTML DOM node.
- * @return {boolean} Whether or not the html node is visible.
- */
-TraverseUtil.isVisible = function(node) {
- if (!node.style)
- return true;
- var style = window.getComputedStyle(/** @type {Element} */(node), null);
- return (!!style && style.display != 'none' && style.visibility != 'hidden');
-};
-
-/**
- * Use the class name to figure out if this DOM node should be traversed.
- * @param {Node} node A HTML DOM node.
- * @return {boolean} Whether or not the html node should be traversed.
- */
-TraverseUtil.isSkipped = function(node) {
- if (node.constructor == Text)
- node = node.parentElement;
- if (node.className == 'CaretBrowsing_Caret' ||
- node.className == 'CaretBrowsing_AnimateCaret') {
- return true;
- }
- return false;
-};
-
-/**
- * Moves the cursor forwards until it has crossed exactly one character.
- * @param {Cursor} cursor The cursor location where the search should start.
- * On exit, the cursor will be immediately to the right of the
- * character returned.
- * @param {Array.<Node>} nodesCrossed Any HTML nodes crossed between the
- * initial and final cursor position will be pushed onto this array.
- * @return {?string} The character found, or null if the bottom of the
- * document has been reached.
- */
-TraverseUtil.forwardsChar = function(cursor, nodesCrossed) {
- while (true) {
- // Move down until we get to a leaf node.
- var childNode = null;
- if (!TraverseUtil.treatAsLeafNode(cursor.node)) {
- for (var i = cursor.index; i < cursor.node.childNodes.length; i++) {
- var node = cursor.node.childNodes[i];
- if (TraverseUtil.isSkipped(node)) {
- nodesCrossed.push(node);
- continue;
- }
- if (TraverseUtil.isVisible(node)) {
- childNode = node;
- break;
- }
- }
- }
- if (childNode) {
- cursor.node = childNode;
- cursor.index = 0;
- cursor.text = TraverseUtil.getNodeText(cursor.node);
- if (cursor.node.constructor != Text) {
- nodesCrossed.push(cursor.node);
- }
- continue;
- }
-
- // Return the next character from this leaf node.
- if (cursor.index < cursor.text.length)
- return cursor.text[cursor.index++];
-
- // Move to the next sibling, going up the tree as necessary.
- while (cursor.node != null) {
- // Try to move to the next sibling.
- var siblingNode = null;
- for (var node = cursor.node.nextSibling;
- node != null;
- node = node.nextSibling) {
- if (TraverseUtil.isSkipped(node)) {
- nodesCrossed.push(node);
- continue;
- }
- if (TraverseUtil.isVisible(node)) {
- siblingNode = node;
- break;
- }
- }
- if (siblingNode) {
- cursor.node = siblingNode;
- cursor.text = TraverseUtil.getNodeText(siblingNode);
- cursor.index = 0;
-
- if (cursor.node.constructor != Text) {
- nodesCrossed.push(cursor.node);
- }
-
- break;
- }
-
- // Otherwise, move to the parent.
- if (cursor.node.parentNode &&
- cursor.node.parentNode.constructor != HTMLBodyElement) {
- cursor.node = cursor.node.parentNode;
- cursor.text = null;
- cursor.index = 0;
- } else {
- return null;
- }
- }
- }
-};
-
-/**
- * Moves the cursor backwards until it has crossed exactly one character.
- * @param {Cursor} cursor The cursor location where the search should start.
- * On exit, the cursor will be immediately to the left of the
- * character returned.
- * @param {Array.<Node>} nodesCrossed Any HTML nodes crossed between the
- * initial and final cursor position will be pushed onto this array.
- * @return {?string} The previous character, or null if the top of the
- * document has been reached.
- */
-TraverseUtil.backwardsChar = function(cursor, nodesCrossed) {
- while (true) {
- // Move down until we get to a leaf node.
- var childNode = null;
- if (!TraverseUtil.treatAsLeafNode(cursor.node)) {
- for (var i = cursor.index - 1; i >= 0; i--) {
- var node = cursor.node.childNodes[i];
- if (TraverseUtil.isSkipped(node)) {
- nodesCrossed.push(node);
- continue;
- }
- if (TraverseUtil.isVisible(node)) {
- childNode = node;
- break;
- }
- }
- }
- if (childNode) {
- cursor.node = childNode;
- cursor.text = TraverseUtil.getNodeText(cursor.node);
- if (cursor.text.length)
- cursor.index = cursor.text.length;
- else
- cursor.index = cursor.node.childNodes.length;
- if (cursor.node.constructor != Text)
- nodesCrossed.push(cursor.node);
- continue;
- }
-
- // Return the previous character from this leaf node.
- if (cursor.text.length > 0 && cursor.index > 0) {
- return cursor.text[--cursor.index];
- }
-
- // Move to the previous sibling, going up the tree as necessary.
- while (true) {
- // Try to move to the previous sibling.
- var siblingNode = null;
- for (var node = cursor.node.previousSibling;
- node != null;
- node = node.previousSibling) {
- if (TraverseUtil.isSkipped(node)) {
- nodesCrossed.push(node);
- continue;
- }
- if (TraverseUtil.isVisible(node)) {
- siblingNode = node;
- break;
- }
- }
- if (siblingNode) {
- cursor.node = siblingNode;
- cursor.text = TraverseUtil.getNodeText(siblingNode);
- if (cursor.text.length)
- cursor.index = cursor.text.length;
- else
- cursor.index = cursor.node.childNodes.length;
- if (cursor.node.constructor != Text)
- nodesCrossed.push(cursor.node);
- break;
- }
-
- // Otherwise, move to the parent.
- if (cursor.node.parentNode &&
- cursor.node.parentNode.constructor != HTMLBodyElement) {
- cursor.node = cursor.node.parentNode;
- cursor.text = null;
- cursor.index = 0;
- } else {
- return null;
- }
- }
- }
-};
-
-/**
- * Finds the next character, starting from endCursor. Upon exit, startCursor
- * and endCursor will surround the next character. If skipWhitespace is
- * true, will skip until a real character is found. Otherwise, it will
- * attempt to select all of the whitespace between the initial position
- * of endCursor and the next non-whitespace character.
- * @param {Cursor} startCursor On exit, points to the position before
- * the char.
- * @param {Cursor} endCursor The position to start searching for the next
- * char. On exit, will point to the position past the char.
- * @param {Array.<Node>} nodesCrossed Any HTML nodes crossed between the
- * initial and final cursor position will be pushed onto this array.
- * @param {boolean} skipWhitespace If true, will keep scanning until a
- * non-whitespace character is found.
- * @return {?string} The next char, or null if the bottom of the
- * document has been reached.
- */
-TraverseUtil.getNextChar = function(
- startCursor, endCursor, nodesCrossed, skipWhitespace) {
-
- // Save the starting position and get the first character.
- startCursor.copyFrom(endCursor);
- var c = TraverseUtil.forwardsChar(endCursor, nodesCrossed);
- if (c == null)
- return null;
-
- // Keep track of whether the first character was whitespace.
- var initialWhitespace = TraverseUtil.isWhitespace(c);
-
- // Keep scanning until we find a non-whitespace or non-skipped character.
- while ((TraverseUtil.isWhitespace(c)) ||
- (TraverseUtil.isSkipped(endCursor.node))) {
- c = TraverseUtil.forwardsChar(endCursor, nodesCrossed);
- if (c == null)
- return null;
- }
- if (skipWhitespace || !initialWhitespace) {
- // If skipWhitepace is true, or if the first character we encountered
- // was not whitespace, return that non-whitespace character.
- startCursor.copyFrom(endCursor);
- startCursor.index--;
- return c;
- }
- else {
- for (var i = 0; i < nodesCrossed.length; i++) {
- if (TraverseUtil.isSkipped(nodesCrossed[i])) {
- // We need to make sure that startCursor and endCursor aren't
- // surrounding a skippable node.
- endCursor.index--;
- startCursor.copyFrom(endCursor);
- startCursor.index--;
- return ' ';
- }
- }
- // Otherwise, return all of the whitespace before that last character.
- endCursor.index--;
- return ' ';
- }
-};
-
-/**
- * Finds the previous character, starting from startCursor. Upon exit,
- * startCursor and endCursor will surround the previous character.
- * If skipWhitespace is true, will skip until a real character is found.
- * Otherwise, it will attempt to select all of the whitespace between
- * the initial position of endCursor and the next non-whitespace character.
- * @param {Cursor} startCursor The position to start searching for the
- * char. On exit, will point to the position before the char.
- * @param {Cursor} endCursor The position to start searching for the next
- * char. On exit, will point to the position past the char.
- * @param {Array.<Node>} nodesCrossed Any HTML nodes crossed between the
- * initial and final cursor position will be pushed onto this array.
- * @param {boolean} skipWhitespace If true, will keep scanning until a
- * non-whitespace character is found.
- * @return {?string} The previous char, or null if the top of the
- * document has been reached.
- */
-TraverseUtil.getPreviousChar = function(
- startCursor, endCursor, nodesCrossed, skipWhitespace) {
-
- // Save the starting position and get the first character.
- endCursor.copyFrom(startCursor);
- var c = TraverseUtil.backwardsChar(startCursor, nodesCrossed);
- if (c == null)
- return null;
-
- // Keep track of whether the first character was whitespace.
- var initialWhitespace = TraverseUtil.isWhitespace(c);
-
- // Keep scanning until we find a non-whitespace or non-skipped character.
- while ((TraverseUtil.isWhitespace(c)) ||
- (TraverseUtil.isSkipped(startCursor.node))) {
- c = TraverseUtil.backwardsChar(startCursor, nodesCrossed);
- if (c == null)
- return null;
- }
- if (skipWhitespace || !initialWhitespace) {
- // If skipWhitepace is true, or if the first character we encountered
- // was not whitespace, return that non-whitespace character.
- endCursor.copyFrom(startCursor);
- endCursor.index++;
- return c;
- } else {
- for (var i = 0; i < nodesCrossed.length; i++) {
- if (TraverseUtil.isSkipped(nodesCrossed[i])) {
- startCursor.index++;
- endCursor.copyFrom(startCursor);
- endCursor.index++;
- return ' ';
- }
- }
- // Otherwise, return all of the whitespace before that last character.
- startCursor.index++;
- return ' ';
- }
-};
-
-/**
- * Finds the next word, starting from endCursor. Upon exit, startCursor
- * and endCursor will surround the next word. A word is defined to be
- * a string of 1 or more non-whitespace characters in the same DOM node.
- * @param {Cursor} startCursor On exit, will point to the beginning of the
- * word returned.
- * @param {Cursor} endCursor The position to start searching for the next
- * word. On exit, will point to the end of the word returned.
- * @param {Array.<Node>} nodesCrossed Any HTML nodes crossed between the
- * initial and final cursor position will be pushed onto this array.
- * @return {?string} The next word, or null if the bottom of the
- * document has been reached.
- */
-TraverseUtil.getNextWord = function(startCursor, endCursor,
- nodesCrossed) {
-
- // Find the first non-whitespace or non-skipped character.
- var cursor = endCursor.clone();
- var c = TraverseUtil.forwardsChar(cursor, nodesCrossed);
- if (c == null)
- return null;
- while ((TraverseUtil.isWhitespace(c)) ||
- (TraverseUtil.isSkipped(cursor.node))) {
- c = TraverseUtil.forwardsChar(cursor, nodesCrossed);
- if (c == null)
- return null;
- }
-
- // Set startCursor to the position immediately before the first
- // character in our word. It's safe to decrement |index| because
- // forwardsChar guarantees that the cursor will be immediately to the
- // right of the returned character on exit.
- startCursor.copyFrom(cursor);
- startCursor.index--;
-
- // Keep building up our word until we reach a whitespace character or
- // would cross a tag. Don't actually return any tags crossed, because this
- // word goes up until the tag boundary but not past it.
- endCursor.copyFrom(cursor);
- var word = c;
- var newNodesCrossed = [];
- c = TraverseUtil.forwardsChar(cursor, newNodesCrossed);
- if (c == null) {
- return word;
- }
- while (!TraverseUtil.isWhitespace(c) &&
- newNodesCrossed.length == 0) {
- word += c;
- endCursor.copyFrom(cursor);
- c = TraverseUtil.forwardsChar(cursor, newNodesCrossed);
- if (c == null) {
- return word;
- }
- }
- return word;
-};
-
-/**
- * Finds the previous word, starting from startCursor. Upon exit, startCursor
- * and endCursor will surround the previous word. A word is defined to be
- * a string of 1 or more non-whitespace characters in the same DOM node.
- * @param {Cursor} startCursor The position to start searching for the
- * previous word. On exit, will point to the beginning of the
- * word returned.
- * @param {Cursor} endCursor On exit, will point to the end of the
- * word returned.
- * @param {Array.<Node>} nodesCrossed Any HTML nodes crossed between the
- * initial and final cursor position will be pushed onto this array.
- * @return {?string} The previous word, or null if the bottom of the
- * document has been reached.
- */
-TraverseUtil.getPreviousWord = function(startCursor, endCursor,
- nodesCrossed) {
- // Find the first non-whitespace or non-skipped character.
- var cursor = startCursor.clone();
- var c = TraverseUtil.backwardsChar(cursor, nodesCrossed);
- if (c == null)
- return null;
- while ((TraverseUtil.isWhitespace(c) ||
- (TraverseUtil.isSkipped(cursor.node)))) {
- c = TraverseUtil.backwardsChar(cursor, nodesCrossed);
- if (c == null)
- return null;
- }
-
- // Set endCursor to the position immediately after the first
- // character we've found (the last character of the word, since we're
- // searching backwards).
- endCursor.copyFrom(cursor);
- endCursor.index++;
-
- // Keep building up our word until we reach a whitespace character or
- // would cross a tag. Don't actually return any tags crossed, because this
- // word goes up until the tag boundary but not past it.
- startCursor.copyFrom(cursor);
- var word = c;
- var newNodesCrossed = [];
- c = TraverseUtil.backwardsChar(cursor, newNodesCrossed);
- if (c == null)
- return word;
- while (!TraverseUtil.isWhitespace(c) &&
- newNodesCrossed.length == 0) {
- word = c + word;
- startCursor.copyFrom(cursor);
- c = TraverseUtil.backwardsChar(cursor, newNodesCrossed);
- if (c == null)
- return word;
- }
-
- return word;
-};
-
-/**
- * Finds the next sentence, starting from endCursor. Upon exit,
- * startCursor and endCursor will surround the next sentence.
- *
- * @param {Cursor} startCursor On exit, marks the beginning of the sentence.
- * @param {Cursor} endCursor The position to start searching for the next
- * sentence. On exit, will point to the end of the returned string.
- * @param {Array.<Node>} nodesCrossed Any HTML nodes crossed between the
- * initial and final cursor position will be pushed onto this array.
- * @param {Object} breakTags Associative array of tags that should break
- * the sentence.
- * @return {?string} The next sentence, or null if the bottom of the
- * document has been reached.
- */
-TraverseUtil.getNextSentence = function(
- startCursor, endCursor, nodesCrossed, breakTags) {
- return TraverseUtil.getNextString(
- startCursor, endCursor, nodesCrossed,
- function(str, word, nodes) {
- if (str.substr(-1) == '.')
- return true;
- for (var i = 0; i < nodes.length; i++) {
- if (TraverseUtil.isSkipped(nodes[i])) {
- return true;
- }
- var style = window.getComputedStyle(nodes[i], null);
- if (style && (style.display != 'inline' ||
- breakTags[nodes[i].tagName])) {
- return true;
- }
- }
- return false;
- });
-};
-
-/**
- * Finds the previous sentence, starting from startCursor. Upon exit,
- * startCursor and endCursor will surround the previous sentence.
- *
- * @param {Cursor} startCursor The position to start searching for the next
- * sentence. On exit, will point to the start of the returned string.
- * @param {Cursor} endCursor On exit, the end of the returned string.
- * @param {Array.<Node>} nodesCrossed Any HTML nodes crossed between the
- * initial and final cursor position will be pushed onto this array.
- * @param {Object} breakTags Associative array of tags that should break
- * the sentence.
- * @return {?string} The previous sentence, or null if the bottom of the
- * document has been reached.
- */
-TraverseUtil.getPreviousSentence = function(
- startCursor, endCursor, nodesCrossed, breakTags) {
- return TraverseUtil.getPreviousString(
- startCursor, endCursor, nodesCrossed,
- function(str, word, nodes) {
- if (word.substr(-1) == '.')
- return true;
- for (var i = 0; i < nodes.length; i++) {
- if (TraverseUtil.isSkipped(nodes[i])) {
- return true;
- }
- var style = window.getComputedStyle(nodes[i], null);
- if (style && (style.display != 'inline' ||
- breakTags[nodes[i].tagName])) {
- return true;
- }
- }
- return false;
- });
-};
-
-/**
- * Finds the next line, starting from endCursor. Upon exit,
- * startCursor and endCursor will surround the next line.
- *
- * @param {Cursor} startCursor On exit, marks the beginning of the line.
- * @param {Cursor} endCursor The position to start searching for the next
- * line. On exit, will point to the end of the returned string.
- * @param {Array.<Node>} nodesCrossed Any HTML nodes crossed between the
- * initial and final cursor position will be pushed onto this array.
- * @param {number} lineLength The maximum number of characters in a line.
- * @param {Object} breakTags Associative array of tags that should break
- * the line.
- * @return {?string} The next line, or null if the bottom of the
- * document has been reached.
- */
-TraverseUtil.getNextLine = function(
- startCursor, endCursor, nodesCrossed, lineLength, breakTags) {
- return TraverseUtil.getNextString(
- startCursor, endCursor, nodesCrossed,
- function(str, word, nodes) {
- if (str.length + word.length + 1 > lineLength)
- return true;
- for (var i = 0; i < nodes.length; i++) {
- if (TraverseUtil.isSkipped(nodes[i])) {
- return true;
- }
- var style = window.getComputedStyle(nodes[i], null);
- if (style && (style.display != 'inline' ||
- breakTags[nodes[i].tagName])) {
- return true;
- }
- }
- return false;
- });
-};
-
-/**
- * Finds the previous line, starting from startCursor. Upon exit,
- * startCursor and endCursor will surround the previous line.
- *
- * @param {Cursor} startCursor The position to start searching for the next
- * line. On exit, will point to the start of the returned string.
- * @param {Cursor} endCursor On exit, the end of the returned string.
- * @param {Array.<Node>} nodesCrossed Any HTML nodes crossed between the
- * initial and final cursor position will be pushed onto this array.
- * @param {number} lineLength The maximum number of characters in a line.
- * @param {Object} breakTags Associative array of tags that should break
- * the sentence.
- * @return {?string} The previous line, or null if the bottom of the
- * document has been reached.
- */
-TraverseUtil.getPreviousLine = function(
- startCursor, endCursor, nodesCrossed, lineLength, breakTags) {
- return TraverseUtil.getPreviousString(
- startCursor, endCursor, nodesCrossed,
- function(str, word, nodes) {
- if (str.length + word.length + 1 > lineLength)
- return true;
- for (var i = 0; i < nodes.length; i++) {
- if (TraverseUtil.isSkipped(nodes[i])) {
- return true;
- }
- var style = window.getComputedStyle(nodes[i], null);
- if (style && (style.display != 'inline' ||
- breakTags[nodes[i].tagName])) {
- return true;
- }
- }
- return false;
- });
-};
-
-/**
- * Finds the next paragraph, starting from endCursor. Upon exit,
- * startCursor and endCursor will surround the next paragraph.
- *
- * @param {Cursor} startCursor On exit, marks the beginning of the paragraph.
- * @param {Cursor} endCursor The position to start searching for the next
- * paragraph. On exit, will point to the end of the returned string.
- * @param {Array.<Node>} nodesCrossed Any HTML nodes crossed between the
- * initial and final cursor position will be pushed onto this array.
- * @return {?string} The next paragraph, or null if the bottom of the
- * document has been reached.
- */
-TraverseUtil.getNextParagraph = function(startCursor, endCursor,
- nodesCrossed) {
- return TraverseUtil.getNextString(
- startCursor, endCursor, nodesCrossed,
- function(str, word, nodes) {
- for (var i = 0; i < nodes.length; i++) {
- if (TraverseUtil.isSkipped(nodes[i])) {
- return true;
- }
- var style = window.getComputedStyle(nodes[i], null);
- if (style && style.display != 'inline') {
- return true;
- }
- }
- return false;
- });
-};
-
-/**
- * Finds the previous paragraph, starting from startCursor. Upon exit,
- * startCursor and endCursor will surround the previous paragraph.
- *
- * @param {Cursor} startCursor The position to start searching for the next
- * paragraph. On exit, will point to the start of the returned string.
- * @param {Cursor} endCursor On exit, the end of the returned string.
- * @param {Array.<Node>} nodesCrossed Any HTML nodes crossed between the
- * initial and final cursor position will be pushed onto this array.
- * @return {?string} The previous paragraph, or null if the bottom of the
- * document has been reached.
- */
-TraverseUtil.getPreviousParagraph = function(
- startCursor, endCursor, nodesCrossed) {
- return TraverseUtil.getPreviousString(
- startCursor, endCursor, nodesCrossed,
- function(str, word, nodes) {
- for (var i = 0; i < nodes.length; i++) {
- if (TraverseUtil.isSkipped(nodes[i])) {
- return true;
- }
- var style = window.getComputedStyle(nodes[i], null);
- if (style && style.display != 'inline') {
- return true;
- }
- }
- return false;
- });
-};
-
-/**
- * Customizable function to return the next string of words in the DOM, based
- * on provided functions to decide when to break one string and start
- * the next. This can be used to get the next sentence, line, paragraph,
- * or potentially other granularities.
- *
- * Finds the next contiguous string, starting from endCursor. Upon exit,
- * startCursor and endCursor will surround the next string.
- *
- * The breakBefore function takes three parameters, and
- * should return true if the string should be broken before the proposed
- * next word:
- * str The string so far.
- * word The next word to be added.
- * nodesCrossed The nodes crossed in reaching this next word.
- *
- * @param {Cursor} startCursor On exit, will point to the beginning of the
- * next string.
- * @param {Cursor} endCursor The position to start searching for the next
- * string. On exit, will point to the end of the returned string.
- * @param {Array.<Node>} nodesCrossed Any HTML nodes crossed between the
- * initial and final cursor position will be pushed onto this array.
- * @param {function(string, string, Array.<string>)} breakBefore
- * Function that takes the string so far, next word to be added, and
- * nodes crossed, and returns true if the string should be ended before
- * adding this word.
- * @return {?string} The next string, or null if the bottom of the
- * document has been reached.
- */
-TraverseUtil.getNextString = function(
- startCursor, endCursor, nodesCrossed, breakBefore) {
- // Get the first word and set the start cursor to the start of the
- // first word.
- var wordStartCursor = endCursor.clone();
- var wordEndCursor = endCursor.clone();
- var newNodesCrossed = [];
- var str = '';
- var word = TraverseUtil.getNextWord(
- wordStartCursor, wordEndCursor, newNodesCrossed);
- if (word == null)
- return null;
- startCursor.copyFrom(wordStartCursor);
-
- // Always add the first word when the string is empty, and then keep
- // adding more words as long as breakBefore returns false
- while (!str || !breakBefore(str, word, newNodesCrossed)) {
- // Append this word, set the end cursor to the end of this word, and
- // update the returned list of nodes crossed to include ones we crossed
- // in reaching this word.
- if (str)
- str += ' ';
- str += word;
- nodesCrossed = nodesCrossed.concat(newNodesCrossed);
- endCursor.copyFrom(wordEndCursor);
-
- // Get the next word and go back to the top of the loop.
- newNodesCrossed = [];
- word = TraverseUtil.getNextWord(
- wordStartCursor, wordEndCursor, newNodesCrossed);
- if (word == null)
- return str;
- }
-
- return str;
-};
-
-/**
- * Customizable function to return the previous string of words in the DOM,
- * based on provided functions to decide when to break one string and start
- * the next. See getNextString, above, for more details.
- *
- * Finds the previous contiguous string, starting from startCursor. Upon exit,
- * startCursor and endCursor will surround the next string.
- *
- * @param {Cursor} startCursor The position to start searching for the
- * previous string. On exit, will point to the beginning of the
- * string returned.
- * @param {Cursor} endCursor On exit, will point to the end of the
- * string returned.
- * @param {Array.<Node>} nodesCrossed Any HTML nodes crossed between the
- * initial and final cursor position will be pushed onto this array.
- * @param {function(string, string, Array.<string>)} breakBefore
- * Function that takes the string so far, the word to be added, and
- * nodes crossed, and returns true if the string should be ended before
- * adding this word.
- * @return {?string} The next string, or null if the top of the
- * document has been reached.
- */
-TraverseUtil.getPreviousString = function(
- startCursor, endCursor, nodesCrossed, breakBefore) {
- // Get the first word and set the end cursor to the end of the
- // first word.
- var wordStartCursor = startCursor.clone();
- var wordEndCursor = startCursor.clone();
- var newNodesCrossed = [];
- var str = '';
- var word = TraverseUtil.getPreviousWord(
- wordStartCursor, wordEndCursor, newNodesCrossed);
- if (word == null)
- return null;
- endCursor.copyFrom(wordEndCursor);
-
- // Always add the first word when the string is empty, and then keep
- // adding more words as long as breakBefore returns false
- while (!str || !breakBefore(str, word, newNodesCrossed)) {
- // Prepend this word, set the start cursor to the start of this word, and
- // update the returned list of nodes crossed to include ones we crossed
- // in reaching this word.
- if (str)
- str = ' ' + str;
- str = word + str;
- nodesCrossed = nodesCrossed.concat(newNodesCrossed);
- startCursor.copyFrom(wordStartCursor);
-v
- // Get the previous word and go back to the top of the loop.
- newNodesCrossed = [];
- word = TraverseUtil.getPreviousWord(
- wordStartCursor, wordEndCursor, newNodesCrossed);
- if (word == null)
- return str;
- }
-
- return str;
-};
« no previous file with comments | « ui/accessibility/extensions/caretbrowsing/options.js ('k') | ui/accessibility/extensions/highcontrast/background.js » ('j') | no next file with comments »

Powered by Google App Engine
This is Rietveld 408576698