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JavaScript

//.CommonJS
var CSSOM = {
CSSValue: require('./CSSValue').CSSValue
};
///CommonJS
/**
* @constructor
* @see http://msdn.microsoft.com/en-us/library/ms537634(v=vs.85).aspx
*
*/
CSSOM.CSSValueExpression = function CSSValueExpression(token, idx) {
this._token = token;
this._idx = idx;
};
CSSOM.CSSValueExpression.prototype = new CSSOM.CSSValue();
CSSOM.CSSValueExpression.prototype.constructor = CSSOM.CSSValueExpression;
/**
* parse css expression() value
*
* @return {Object}
* - error:
* or
* - idx:
* - expression:
*
* Example:
*
* .selector {
* zoom: expression(documentElement.clientWidth > 1000 ? '1000px' : 'auto');
* }
*/
CSSOM.CSSValueExpression.prototype.parse = function() {
var token = this._token,
idx = this._idx;
var character = '',
expression = '',
error = '',
info,
paren = [];
for (; ; ++idx) {
character = token.charAt(idx);
// end of token
if (character === '') {
error = 'css expression error: unfinished expression!';
break;
}
switch(character) {
case '(':
paren.push(character);
expression += character;
break;
case ')':
paren.pop(character);
expression += character;
break;
case '/':
if ((info = this._parseJSComment(token, idx))) { // comment?
if (info.error) {
error = 'css expression error: unfinished comment in expression!';
} else {
idx = info.idx;
// ignore the comment
}
} else if ((info = this._parseJSRexExp(token, idx))) { // regexp
idx = info.idx;
expression += info.text;
} else { // other
expression += character;
}
break;
case "'":
case '"':
info = this._parseJSString(token, idx, character);
if (info) { // string
idx = info.idx;
expression += info.text;
} else {
expression += character;
}
break;
default:
expression += character;
break;
}
if (error) {
break;
}
// end of expression
if (paren.length === 0) {
break;
}
}
var ret;
if (error) {
ret = {
error: error
};
} else {
ret = {
idx: idx,
expression: expression
};
}
return ret;
};
/**
*
* @return {Object|false}
* - idx:
* - text:
* or
* - error:
* or
* false
*
*/
CSSOM.CSSValueExpression.prototype._parseJSComment = function(token, idx) {
var nextChar = token.charAt(idx + 1),
text;
if (nextChar === '/' || nextChar === '*') {
var startIdx = idx,
endIdx,
commentEndChar;
if (nextChar === '/') { // line comment
commentEndChar = '\n';
} else if (nextChar === '*') { // block comment
commentEndChar = '*/';
}
endIdx = token.indexOf(commentEndChar, startIdx + 1 + 1);
if (endIdx !== -1) {
endIdx = endIdx + commentEndChar.length - 1;
text = token.substring(idx, endIdx + 1);
return {
idx: endIdx,
text: text
};
} else {
var error = 'css expression error: unfinished comment in expression!';
return {
error: error
};
}
} else {
return false;
}
};
/**
*
* @return {Object|false}
* - idx:
* - text:
* or
* false
*
*/
CSSOM.CSSValueExpression.prototype._parseJSString = function(token, idx, sep) {
var endIdx = this._findMatchedIdx(token, idx, sep),
text;
if (endIdx === -1) {
return false;
} else {
text = token.substring(idx, endIdx + sep.length);
return {
idx: endIdx,
text: text
};
}
};
/**
* parse regexp in css expression
*
* @return {Object|false}
* - idx:
* - regExp:
* or
* false
*/
/*
all legal RegExp
/a/
(/a/)
[/a/]
[12, /a/]
!/a/
+/a/
-/a/
* /a/
/ /a/
%/a/
===/a/
!==/a/
==/a/
!=/a/
>/a/
>=/a/
</a/
<=/a/
&/a/
|/a/
^/a/
~/a/
<</a/
>>/a/
>>>/a/
&&/a/
||/a/
?/a/
=/a/
,/a/
delete /a/
in /a/
instanceof /a/
new /a/
typeof /a/
void /a/
*/
CSSOM.CSSValueExpression.prototype._parseJSRexExp = function(token, idx) {
var before = token.substring(0, idx).replace(/\s+$/, ""),
legalRegx = [
/^$/,
/\($/,
/\[$/,
/\!$/,
/\+$/,
/\-$/,
/\*$/,
/\/\s+/,
/\%$/,
/\=$/,
/\>$/,
/<$/,
/\&$/,
/\|$/,
/\^$/,
/\~$/,
/\?$/,
/\,$/,
/delete$/,
/in$/,
/instanceof$/,
/new$/,
/typeof$/,
/void$/
];
var isLegal = legalRegx.some(function(reg) {
return reg.test(before);
});
if (!isLegal) {
return false;
} else {
var sep = '/';
// same logic as string
return this._parseJSString(token, idx, sep);
}
};
/**
*
* find next sep(same line) index in `token`
*
* @return {Number}
*
*/
CSSOM.CSSValueExpression.prototype._findMatchedIdx = function(token, idx, sep) {
var startIdx = idx,
endIdx;
var NOT_FOUND = -1;
while(true) {
endIdx = token.indexOf(sep, startIdx + 1);
if (endIdx === -1) { // not found
endIdx = NOT_FOUND;
break;
} else {
var text = token.substring(idx + 1, endIdx),
matched = text.match(/\\+$/);
if (!matched || matched[0] % 2 === 0) { // not escaped
break;
} else {
startIdx = endIdx;
}
}
}
// boundary must be in the same line(js sting or regexp)
var nextNewLineIdx = token.indexOf('\n', idx + 1);
if (nextNewLineIdx < endIdx) {
endIdx = NOT_FOUND;
}
return endIdx;
};
//.CommonJS
exports.CSSValueExpression = CSSOM.CSSValueExpression;
///CommonJS