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|
// Copyright 2006-2008, The Google Caja project.
// Modifications Copyright 2009 The Closure Library Authors. All Rights Reserved.
// All Rights Reserved
/**
* @license Portions of this code are from the google-caja project, received by
* Google under the Apache license (http://code.google.com/p/google-caja/).
* All other code is Copyright 2009 Google, Inc. All Rights Reserved.
// Copyright (C) 2006 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 A Html SAX parser.
*
* Examples of usage of the {@code goog.string.html.HtmlParser}:
* <pre>
* var handler = new MyCustomHtmlVisitorHandlerThatExtendsHtmlSaxHandler();
* var parser = new goog.string.html.HtmlParser();
* parser.parse(handler, '<html><a href="google.com">link found!</a></html>');
* </pre>
*
* TODO(user, msamuel): validate sanitizer regex against the HTML5 grammar at
* http://www.whatwg.org/specs/web-apps/current-work/multipage/syntax.html
* http://www.whatwg.org/specs/web-apps/current-work/multipage/parsing.html
* http://www.whatwg.org/specs/web-apps/current-work/multipage/tokenization.html
* http://www.whatwg.org/specs/web-apps/current-work/multipage/tree-construction.html
*
* @supported IE6, IE7, IE8, FF1.5, FF2, FF3, Chrome 3.0, Safari and Opera 10.
*/
goog.provide('goog.string.html.HtmlParser');
goog.provide('goog.string.html.HtmlParser.EFlags');
goog.provide('goog.string.html.HtmlParser.Elements');
goog.provide('goog.string.html.HtmlParser.Entities');
goog.provide('goog.string.html.HtmlSaxHandler');
/**
* An Html parser: {@code parse} takes a string and calls methods on
* {@code goog.string.html.HtmlSaxHandler} while it is visiting it.
*
* @constructor
*/
goog.string.html.HtmlParser = function() {
};
/**
* HTML entities that are encoded/decoded.
* TODO(user): use {@code goog.string.htmlEncode} instead.
* @enum {string}
*/
goog.string.html.HtmlParser.Entities = {
lt: '<',
gt: '>',
amp: '&',
nbsp: '\240',
quot: '"',
apos: '\''
};
/**
* The html eflags, used internally on the parser.
* @enum {number}
*/
goog.string.html.HtmlParser.EFlags = {
OPTIONAL_ENDTAG: 1,
EMPTY: 2,
CDATA: 4,
RCDATA: 8,
UNSAFE: 16,
FOLDABLE: 32
};
/**
* A map of element to a bitmap of flags it has, used internally on the parser.
* @type {Object}
*/
goog.string.html.HtmlParser.Elements = {
'a': 0,
'abbr': 0,
'acronym': 0,
'address': 0,
'applet': goog.string.html.HtmlParser.EFlags.UNSAFE,
'area': goog.string.html.HtmlParser.EFlags.EMPTY,
'b': 0,
'base': goog.string.html.HtmlParser.EFlags.EMPTY |
goog.string.html.HtmlParser.EFlags.UNSAFE,
'basefont': goog.string.html.HtmlParser.EFlags.EMPTY |
goog.string.html.HtmlParser.EFlags.UNSAFE,
'bdo': 0,
'big': 0,
'blockquote': 0,
'body': goog.string.html.HtmlParser.EFlags.OPTIONAL_ENDTAG |
goog.string.html.HtmlParser.EFlags.UNSAFE |
goog.string.html.HtmlParser.EFlags.FOLDABLE,
'br': goog.string.html.HtmlParser.EFlags.EMPTY,
'button': 0,
'caption': 0,
'center': 0,
'cite': 0,
'code': 0,
'col': goog.string.html.HtmlParser.EFlags.EMPTY,
'colgroup': goog.string.html.HtmlParser.EFlags.OPTIONAL_ENDTAG,
'dd': goog.string.html.HtmlParser.EFlags.OPTIONAL_ENDTAG,
'del': 0,
'dfn': 0,
'dir': 0,
'div': 0,
'dl': 0,
'dt': goog.string.html.HtmlParser.EFlags.OPTIONAL_ENDTAG,
'em': 0,
'fieldset': 0,
'font': 0,
'form': 0,
'frame': goog.string.html.HtmlParser.EFlags.EMPTY |
goog.string.html.HtmlParser.EFlags.UNSAFE,
'frameset': goog.string.html.HtmlParser.EFlags.UNSAFE,
'h1': 0,
'h2': 0,
'h3': 0,
'h4': 0,
'h5': 0,
'h6': 0,
'head': goog.string.html.HtmlParser.EFlags.OPTIONAL_ENDTAG |
goog.string.html.HtmlParser.EFlags.UNSAFE |
goog.string.html.HtmlParser.EFlags.FOLDABLE,
'hr': goog.string.html.HtmlParser.EFlags.EMPTY,
'html': goog.string.html.HtmlParser.EFlags.OPTIONAL_ENDTAG |
goog.string.html.HtmlParser.EFlags.UNSAFE |
goog.string.html.HtmlParser.EFlags.FOLDABLE,
'i': 0,
'iframe': goog.string.html.HtmlParser.EFlags.UNSAFE |
goog.string.html.HtmlParser.EFlags.CDATA,
'img': goog.string.html.HtmlParser.EFlags.EMPTY,
'input': goog.string.html.HtmlParser.EFlags.EMPTY,
'ins': 0,
'isindex': goog.string.html.HtmlParser.EFlags.EMPTY |
goog.string.html.HtmlParser.EFlags.UNSAFE,
'kbd': 0,
'label': 0,
'legend': 0,
'li': goog.string.html.HtmlParser.EFlags.OPTIONAL_ENDTAG,
'link': goog.string.html.HtmlParser.EFlags.EMPTY |
goog.string.html.HtmlParser.EFlags.UNSAFE,
'map': 0,
'menu': 0,
'meta': goog.string.html.HtmlParser.EFlags.EMPTY |
goog.string.html.HtmlParser.EFlags.UNSAFE,
'noframes': goog.string.html.HtmlParser.EFlags.UNSAFE |
goog.string.html.HtmlParser.EFlags.CDATA,
'noscript': goog.string.html.HtmlParser.EFlags.UNSAFE |
goog.string.html.HtmlParser.EFlags.CDATA,
'object': goog.string.html.HtmlParser.EFlags.UNSAFE,
'ol': 0,
'optgroup': 0,
'option': goog.string.html.HtmlParser.EFlags.OPTIONAL_ENDTAG,
'p': goog.string.html.HtmlParser.EFlags.OPTIONAL_ENDTAG,
'param': goog.string.html.HtmlParser.EFlags.EMPTY |
goog.string.html.HtmlParser.EFlags.UNSAFE,
'pre': 0,
'q': 0,
's': 0,
'samp': 0,
'script': goog.string.html.HtmlParser.EFlags.UNSAFE |
goog.string.html.HtmlParser.EFlags.CDATA,
'select': 0,
'small': 0,
'span': 0,
'strike': 0,
'strong': 0,
'style': goog.string.html.HtmlParser.EFlags.UNSAFE |
goog.string.html.HtmlParser.EFlags.CDATA,
'sub': 0,
'sup': 0,
'table': 0,
'tbody': goog.string.html.HtmlParser.EFlags.OPTIONAL_ENDTAG,
'td': goog.string.html.HtmlParser.EFlags.OPTIONAL_ENDTAG,
'textarea': goog.string.html.HtmlParser.EFlags.RCDATA,
'tfoot': goog.string.html.HtmlParser.EFlags.OPTIONAL_ENDTAG,
'th': goog.string.html.HtmlParser.EFlags.OPTIONAL_ENDTAG,
'thead': goog.string.html.HtmlParser.EFlags.OPTIONAL_ENDTAG,
'title': goog.string.html.HtmlParser.EFlags.RCDATA |
goog.string.html.HtmlParser.EFlags.UNSAFE,
'tr': goog.string.html.HtmlParser.EFlags.OPTIONAL_ENDTAG,
'tt': 0,
'u': 0,
'ul': 0,
'var': 0
};
/**
* Regular expression that matches &s.
* @type {RegExp}
* @private
*/
goog.string.html.HtmlParser.AMP_RE_ = /&/g;
/**
* Regular expression that matches loose &s.
* @type {RegExp}
* @private
*/
goog.string.html.HtmlParser.LOOSE_AMP_RE_ =
/&([^a-z#]|#(?:[^0-9x]|x(?:[^0-9a-f]|$)|$)|$)/gi;
/**
* Regular expression that matches <.
* @type {RegExp}
* @private
*/
goog.string.html.HtmlParser.LT_RE_ = /</g;
/**
* Regular expression that matches >.
* @type {RegExp}
* @private
*/
goog.string.html.HtmlParser.GT_RE_ = />/g;
/**
* Regular expression that matches ".
* @type {RegExp}
* @private
*/
goog.string.html.HtmlParser.QUOTE_RE_ = /\"/g;
/**
* Regular expression that matches =.
* @type {RegExp}
* @private
*/
goog.string.html.HtmlParser.EQUALS_RE_ = /=/g;
/**
* Regular expression that matches null characters.
* @type {RegExp}
* @private
*/
goog.string.html.HtmlParser.NULL_RE_ = /\0/g;
/**
* Regular expression that matches entities.
* @type {RegExp}
* @private
*/
goog.string.html.HtmlParser.ENTITY_RE_ = /&(#\d+|#x[0-9A-Fa-f]+|\w+);/g;
/**
* Regular expression that matches decimal numbers.
* @type {RegExp}
* @private
*/
goog.string.html.HtmlParser.DECIMAL_ESCAPE_RE_ = /^#(\d+)$/;
/**
* Regular expression that matches hexadecimal numbers.
* @type {RegExp}
* @private
*/
goog.string.html.HtmlParser.HEX_ESCAPE_RE_ = /^#x([0-9A-Fa-f]+)$/;
/**
* Regular expression that matches the next token to be processed.
* @type {RegExp}
* @private
*/
goog.string.html.HtmlParser.INSIDE_TAG_TOKEN_ = new RegExp(
// Don't capture space.
'^\\s*(?:' +
// Capture an attribute name in group 1, and value in group 3.
// We capture the fact that there was an attribute in group 2, since
// interpreters are inconsistent in whether a group that matches nothing
// is null, undefined, or the empty string.
('(?:' +
'([a-z][a-z-]*)' + // attribute name
('(' + // optionally followed
'\\s*=\\s*' +
('(' +
// A double quoted string.
'\"[^\"]*\"' +
// A single quoted string.
'|\'[^\']*\'' +
// The positive lookahead is used to make sure that in
// <foo bar= baz=boo>, the value for bar is blank, not "baz=boo".
'|(?=[a-z][a-z-]*\\s*=)' +
// An unquoted value that is not an attribute name.
// We know it is not an attribute name because the previous
// zero-width match would've eliminated that possibility.
'|[^>\"\'\\s]*' +
')'
) +
')'
) + '?' +
')'
) +
// End of tag captured in group 3.
'|(/?>)' +
// Don't capture cruft
'|[^a-z\\s>]+)',
'i');
/**
* Regular expression that matches the next token to be processed when we are
* outside a tag.
* @type {RegExp}
* @private
*/
goog.string.html.HtmlParser.OUTSIDE_TAG_TOKEN_ = new RegExp(
'^(?:' +
// Entity captured in group 1.
'&(\\#[0-9]+|\\#[x][0-9a-f]+|\\w+);' +
// Comment, doctypes, and processing instructions not captured.
'|<[!]--[\\s\\S]*?-->|<!\\w[^>]*>|<\\?[^>*]*>' +
// '/' captured in group 2 for close tags, and name captured in group 3.
'|<(/)?([a-z][a-z0-9]*)' +
// Text captured in group 4.
'|([^<&>]+)' +
// Cruft captured in group 5.
'|([<&>]))',
'i');
/**
* Given a SAX-like {@code goog.string.html.HtmlSaxHandler} parses a
* {@code htmlText} and lets the {@code handler} know the structure while
* visiting the nodes.
*
* @param {goog.string.html.HtmlSaxHandler} handler The HtmlSaxHandler that will
* receive the events.
* @param {string} htmlText The html text.
*/
goog.string.html.HtmlParser.prototype.parse = function(handler, htmlText) {
var htmlLower = null;
var inTag = false; // True iff we're currently processing a tag.
var attribs = []; // Accumulates attribute names and values.
var tagName; // The name of the tag currently being processed.
var eflags; // The element flags for the current tag.
var openTag; // True if the current tag is an open tag.
// Lets the handler know that we are starting to parse the document.
handler.startDoc();
// Consumes tokens from the htmlText and stops once all tokens are processed.
while (htmlText) {
var regex = inTag ?
goog.string.html.HtmlParser.INSIDE_TAG_TOKEN_ :
goog.string.html.HtmlParser.OUTSIDE_TAG_TOKEN_;
// Gets the next token
var m = htmlText.match(regex);
// And removes it from the string
htmlText = htmlText.substring(m[0].length);
// TODO(goto): cleanup this code breaking it into separate methods.
if (inTag) {
if (m[1]) { // Attribute.
// SetAttribute with uppercase names doesn't work on IE6.
var attribName = goog.string.html.toLowerCase(m[1]);
var decodedValue;
if (m[2]) {
var encodedValue = m[3];
switch (encodedValue.charCodeAt(0)) { // Strip quotes.
case 34: case 39:
encodedValue = encodedValue.substring(
1, encodedValue.length - 1);
break;
}
decodedValue = this.unescapeEntities_(this.stripNULs_(encodedValue));
} else {
// Use name as value for valueless attribs, so
// <input type=checkbox checked>
// gets attributes ['type', 'checkbox', 'checked', 'checked']
decodedValue = attribName;
}
attribs.push(attribName, decodedValue);
} else if (m[4]) {
if (eflags !== void 0) { // False if not in whitelist.
if (openTag) {
if (handler.startTag) {
handler.startTag(/** @type {string} */ (tagName), attribs);
}
} else {
if (handler.endTag) {
handler.endTag(/** @type {string} */ (tagName));
}
}
}
if (openTag && (eflags &
(goog.string.html.HtmlParser.EFlags.CDATA |
goog.string.html.HtmlParser.EFlags.RCDATA))) {
if (htmlLower === null) {
htmlLower = goog.string.html.toLowerCase (htmlText);
} else {
htmlLower = htmlLower.substring(
htmlLower.length - htmlText.length);
}
var dataEnd = htmlLower.indexOf('</' + tagName);
if (dataEnd < 0) {
dataEnd = htmlText.length;
}
if (eflags & goog.string.html.HtmlParser.EFlags.CDATA) {
if (handler.cdata) {
handler.cdata(htmlText.substring(0, dataEnd));
}
} else if (handler.rcdata) {
handler.rcdata(
this.normalizeRCData_(htmlText.substring(0, dataEnd)));
}
htmlText = htmlText.substring(dataEnd);
}
tagName = eflags = openTag = void 0;
attribs.length = 0;
inTag = false;
}
} else {
if (m[1]) { // Entity.
handler.pcdata(m[0]);
} else if (m[3]) { // Tag.
openTag = !m[2];
inTag = true;
tagName = goog.string.html.toLowerCase (m[3]);
eflags = goog.string.html.HtmlParser.Elements.hasOwnProperty(tagName) ?
goog.string.html.HtmlParser.Elements[tagName] : void 0;
} else if (m[4]) { // Text.
handler.pcdata(m[4]);
} else if (m[5]) { // Cruft.
switch (m[5]) {
case '<': handler.pcdata('<'); break;
case '>': handler.pcdata('>'); break;
default: handler.pcdata('&'); break;
}
}
}
}
// Lets the handler know that we are done parsing the document.
handler.endDoc();
};
/**
* Decodes an HTML entity.
*
* @param {string} name The content between the '&' and the ';'.
* @return {string} A single unicode code-point as a string.
* @private
*/
goog.string.html.HtmlParser.prototype.lookupEntity_ = function(name) {
// TODO(goto): use {goog.string.htmlDecode} instead ?
// TODO(goto): π is different from Π
name = goog.string.html.toLowerCase(name);
if (goog.string.html.HtmlParser.Entities.hasOwnProperty(name)) {
return goog.string.html.HtmlParser.Entities[name];
}
var m = name.match(goog.string.html.HtmlParser.DECIMAL_ESCAPE_RE_);
if (m) {
return String.fromCharCode(parseInt(m[1], 10));
} else if (
!!(m = name.match(goog.string.html.HtmlParser.HEX_ESCAPE_RE_))) {
return String.fromCharCode(parseInt(m[1], 16));
}
return '';
};
/**
* Removes null characters on the string.
* @param {string} s The string to have the null characters removed.
* @return {string} A string without null characters.
* @private
*/
goog.string.html.HtmlParser.prototype.stripNULs_ = function(s) {
return s.replace(goog.string.html.HtmlParser.NULL_RE_, '');
};
/**
* The plain text of a chunk of HTML CDATA which possibly containing.
*
* TODO(goto): use {@code goog.string.unescapeEntities} instead ?
* @param {string} s A chunk of HTML CDATA. It must not start or end inside
* an HTML entity.
* @return {string} The unescaped entities.
* @private
*/
goog.string.html.HtmlParser.prototype.unescapeEntities_ = function(s) {
return s.replace(
goog.string.html.HtmlParser.ENTITY_RE_,
goog.bind(this.lookupEntity_, this));
};
/**
* Escape entities in RCDATA that can be escaped without changing the meaning.
* @param {string} rcdata The RCDATA string we want to normalize.
* @return {string} A normalized version of RCDATA.
* @private
*/
goog.string.html.HtmlParser.prototype.normalizeRCData_ = function(rcdata) {
return rcdata.
replace(goog.string.html.HtmlParser.LOOSE_AMP_RE_, '&$1').
replace(goog.string.html.HtmlParser.LT_RE_, '<').
replace(goog.string.html.HtmlParser.GT_RE_, '>');
};
/**
* TODO(goto): why isn't this in the string package ? does this solves any
* real problem ? move it to the goog.string package if it does.
*
* @param {string} str The string to lower case.
* @return {string} The str in lower case format.
*/
goog.string.html.toLowerCase = function(str) {
// The below may not be true on browsers in the Turkish locale.
if ('script' === 'SCRIPT'.toLowerCase()) {
return str.toLowerCase();
} else {
return str.replace(/[A-Z]/g, function(ch) {
return String.fromCharCode(ch.charCodeAt(0) | 32);
});
}
};
/**
* An interface to the {@code goog.string.html.HtmlParser} visitor, that gets
* called while the HTML is being parsed.
*
* @constructor
*/
goog.string.html.HtmlSaxHandler = function() {
};
/**
* Handler called when the parser found a new tag.
* @param {string} name The name of the tag that is starting.
* @param {Array.<string>} attributes The attributes of the tag.
*/
goog.string.html.HtmlSaxHandler.prototype.startTag = goog.abstractMethod;
/**
* Handler called when the parser found a closing tag.
* @param {string} name The name of the tag that is ending.
*/
goog.string.html.HtmlSaxHandler.prototype.endTag = goog.abstractMethod;
/**
* Handler called when PCDATA is found.
* @param {string} text The PCDATA text found.
*/
goog.string.html.HtmlSaxHandler.prototype.pcdata = goog.abstractMethod;
/**
* Handler called when RCDATA is found.
* @param {string} text The RCDATA text found.
*/
goog.string.html.HtmlSaxHandler.prototype.rcdata = goog.abstractMethod;
/**
* Handler called when CDATA is found.
* @param {string} text The CDATA text found.
*/
goog.string.html.HtmlSaxHandler.prototype.cdata = goog.abstractMethod;
/**
* Handler called when the parser is starting to parse the document.
*/
goog.string.html.HtmlSaxHandler.prototype.startDoc = goog.abstractMethod;
/**
* Handler called when the parsing is done.
*/
goog.string.html.HtmlSaxHandler.prototype.endDoc = goog.abstractMethod;
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