gecko/layout/style/CSSUnprefixingService.js

343 lines
15 KiB
JavaScript

/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- /
/* vim: set shiftwidth=2 tabstop=8 autoindent cindent expandtab: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/* Implementation of a service that converts certain vendor-prefixed CSS
properties to their unprefixed equivalents, for sites on a whitelist. */
"use strict";
const Cc = Components.classes;
const Ci = Components.interfaces;
const Cu = Components.utils;
Cu.import("resource://gre/modules/XPCOMUtils.jsm");
function CSSUnprefixingService() {
}
CSSUnprefixingService.prototype = {
// Boilerplate:
classID: Components.ID("{f0729490-e15c-4a2f-a3fb-99e1cc946b42}"),
_xpcom_factory: XPCOMUtils.generateSingletonFactory(CSSUnprefixingService),
QueryInterface: XPCOMUtils.generateQI([Ci.nsICSSUnprefixingService]),
// See documentation in nsICSSUnprefixingService.idl
generateUnprefixedDeclaration: function(aPropName, aRightHalfOfDecl,
aUnprefixedDecl /*out*/) {
// Convert our input strings to lower-case, for easier string-matching.
// (NOTE: If we ever need to add support for unprefixing properties that
// have case-sensitive parts, then we should do these toLowerCase()
// conversions in a more targeted way, to avoid breaking those properties.)
aPropName = aPropName.toLowerCase();
aRightHalfOfDecl = aRightHalfOfDecl.toLowerCase();
// We have several groups of supported properties:
// FIRST GROUP: Properties that can just be handled as aliases:
// ============================================================
const propertiesThatAreJustAliases = {
"-webkit-background-size": "background-size",
"-webkit-box-flex": "flex-grow",
"-webkit-box-ordinal-group": "order",
"-webkit-box-sizing": "box-sizing",
"-webkit-transform": "transform",
"-webkit-transform-origin": "transform-origin",
};
let unprefixedPropName = propertiesThatAreJustAliases[aPropName];
if (unprefixedPropName !== undefined) {
aUnprefixedDecl.value = unprefixedPropName + ":" + aRightHalfOfDecl;
return true;
}
// SECOND GROUP: Properties that take a single keyword, where the
// unprefixed version takes a different (but analogous) set of keywords:
// =====================================================================
const propertiesThatNeedKeywordMapping = {
"-webkit-box-align" : {
unprefixedPropName : "align-items",
valueMap : {
"start" : "flex-start",
"center" : "center",
"end" : "flex-end",
"baseline" : "baseline",
"stretch" : "stretch"
}
},
"-webkit-box-orient" : {
unprefixedPropName : "flex-direction",
valueMap : {
"horizontal" : "row",
"inline-axis" : "row",
"vertical" : "column",
"block-axis" : "column"
}
},
"-webkit-box-pack" : {
unprefixedPropName : "justify-content",
valueMap : {
"start" : "flex-start",
"center" : "center",
"end" : "flex-end",
"justify" : "space-between"
}
},
};
let propInfo = propertiesThatNeedKeywordMapping[aPropName];
if (typeof(propInfo) != "undefined") {
// Regexp for parsing the right half of a declaration, for keyword-valued
// properties. Divides the right half of the declaration into:
// 1) any leading whitespace
// 2) the property value (one or more alphabetical character or hyphen)
// 3) anything after that (e.g. "!important", ";")
// Then we can look up the appropriate unprefixed-property value for the
// value (part 2), and splice that together with the other parts and with
// the unprefixed property-name to make the final declaration.
const keywordValuedPropertyRegexp = /^(\s*)([a-z\-]+)(.*)/;
let parts = keywordValuedPropertyRegexp.exec(aRightHalfOfDecl);
if (!parts) {
// Failed to parse a keyword out of aRightHalfOfDecl. (It probably has
// no alphabetical characters.)
return false;
}
let mappedKeyword = propInfo.valueMap[parts[2]];
if (mappedKeyword === undefined) {
// We found a keyword in aRightHalfOfDecl, but we don't have a mapping
// to an equivalent keyword for the unprefixed version of the property.
return false;
}
aUnprefixedDecl.value = propInfo.unprefixedPropName + ":" +
parts[1] + // any leading whitespace
mappedKeyword +
parts[3]; // any trailing text (e.g. !important, semicolon, etc)
return true;
}
// THIRD GROUP: Properties that may need arbitrary string-replacement:
// ===================================================================
const propertiesThatNeedStringReplacement = {
// "-webkit-transition" takes a multi-part value. If "-webkit-transform"
// appears as part of that value, replace it w/ "transform".
// And regardless, we unprefix the "-webkit-transition" property-name.
// (We could handle other prefixed properties in addition to 'transform'
// here, but in practice "-webkit-transform" is the main one that's
// likely to be transitioned & that we're concerned about supporting.)
"-webkit-transition": {
unprefixedPropName : "transition",
stringMap : {
"-webkit-transform" : "transform",
}
},
};
propInfo = propertiesThatNeedStringReplacement[aPropName];
if (typeof(propInfo) != "undefined") {
let newRightHalf = aRightHalfOfDecl;
for (let strToReplace in propInfo.stringMap) {
let replacement = propInfo.stringMap[strToReplace];
newRightHalf = newRightHalf.split(strToReplace).join(replacement);
}
aUnprefixedDecl.value = propInfo.unprefixedPropName + ":" + newRightHalf;
return true;
}
// No known mapping for property aPropName.
return false;
},
// See documentation in nsICSSUnprefixingService.idl
generateUnprefixedGradientValue: function(aPrefixedFuncName,
aPrefixedFuncBody,
aUnprefixedFuncName, /*[out]*/
aUnprefixedFuncBody /*[out]*/) {
var unprefixedFuncName, newValue;
if (aPrefixedFuncName == "-webkit-gradient") {
// Create expression for oldGradientParser:
var parts = this.oldGradientParser(aPrefixedFuncBody);
var type = parts[0].name;
newValue = this.standardizeOldGradientArgs(type, parts.slice(1));
unprefixedFuncName = type + "-gradient";
}else{ // we're dealing with more modern syntax - should be somewhat easier, at least for linear gradients.
// Fix three things: remove -webkit-, add 'to ' before reversed top/bottom keywords (linear) or 'at ' before position keywords (radial), recalculate deg-values
// -webkit-linear-gradient( [ [ <angle> | [top | bottom] || [left | right] ],]? <color-stop>[, <color-stop>]+);
if (aPrefixedFuncName != "-webkit-linear-gradient" &&
aPrefixedFuncName != "-webkit-radial-gradient") {
// Unrecognized prefixed gradient type
return false;
}
unprefixedFuncName = aPrefixedFuncName.replace(/-webkit-/, '');
// Keywords top, bottom, left, right: can be stand-alone or combined pairwise but in any order ('top left' or 'left top')
// These give the starting edge or corner in the -webkit syntax. The standardised equivalent is 'to ' plus opposite values for linear gradients, 'at ' plus same values for radial gradients
if(unprefixedFuncName.indexOf('linear') > -1){
newValue = aPrefixedFuncBody.replace(/(top|bottom|left|right)+\s*(top|bottom|left|right)*/, function(str){
var words = str.split(/\s+/);
for(var i=0; i<words.length; i++){
switch(words[i].toLowerCase()){
case 'top':
words[i] = 'bottom';
break;
case 'bottom':
words[i] = 'top';
break;
case 'left':
words[i] = 'right';
break;
case 'right':
words[i] = 'left';
}
}
str = words.join(' ');
return ( 'to ' + str);
});
}else{
newValue = aPrefixedFuncBody.replace(/(top|bottom|left|right)+\s/, 'at $1 ');
}
newValue = newValue.replace(/\d+deg/, function (val) {
return (360 - (parseInt(val)-90))+'deg';
});
}
aUnprefixedFuncName.value = unprefixedFuncName;
aUnprefixedFuncBody.value = newValue;
return true;
},
// Helpers for generateUnprefixedGradientValue():
// ----------------------------------------------
oldGradientParser : function(str){
/** This method takes a legacy -webkit-gradient() method call and parses it
to pull out the values, function names and their arguments.
It returns something like [{name:'-webkit-gradient',args:[{name:'linear'}, {name:'top left'} ... ]}]
*/
var objs = [{}], path=[], current, word='', separator_chars = [',', '(', ')'];
current = objs[0], path[0] = objs;
//str = str.replace(/\s*\(/g, '('); // sorry, ws in front of ( would make parsing a lot harder
for(var i = 0; i < str.length; i++){
if(separator_chars.indexOf(str[i]) === -1){
word += str[i];
}else{ // now we have a "separator" - presumably we've also got a "word" or value
current.name = word.trim();
//GM_log(word+' '+path.length+' '+str[i])
word = '';
if(str[i] === '('){ // we assume the 'word' is a function, for example -webkit-gradient() or rgb(), so we create a place to record the arguments
if(!('args' in current)){
current.args = [];
}
current.args.push({});
path.push(current.args);
current = current.args[current.args.length - 1];
path.push(current);
}else if(str[i] === ')'){ // function is ended, no more arguments - go back to appending details to the previous branch of the tree
current = path.pop(); // drop 'current'
current = path.pop(); // drop 'args' reference
}else{
path.pop(); // remove 'current' object from path, we have no arguments to add
var current_parent = path[path.length - 1] || objs; // last object on current path refers to array that contained the previous "current"
current_parent.push({}); // we need a new object to hold this "word" or value
current = current_parent[current_parent.length - 1]; // that object is now the 'current'
path.push(current);
//GM_log(path.length)
}
}
}
return objs;
},
/* Given an array of args for "-webkit-gradient(...)" returned by
* oldGradientParser(), this function constructs a string representing the
* equivalent arguments for a standard "linear-gradient(...)" or
* "radial-gradient(...)" expression.
*
* @param type Either 'linear' or 'radial'.
* @param args An array of args for a "-webkit-gradient(...)" expression,
* provided by oldGradientParser() (not including gradient type).
*/
standardizeOldGradientArgs : function(type, args){
var stdArgStr = "";
var stops = [];
if(/^linear/.test(type)){
// linear gradient, args 1 and 2 tend to be start/end keywords
var points = [].concat(args[0].name.split(/\s+/), args[1].name.split(/\s+/)); // example: [left, top, right, top]
// Old webkit syntax "uses a two-point syntax that lets you explicitly state where a linear gradient starts and ends"
// if start/end keywords are percentages, let's massage the values a little more..
var rxPercTest = /\d+\%/;
if(rxPercTest.test(points[0]) || points[0] == 0){
var startX = parseInt(points[0]), startY = parseInt(points[1]), endX = parseInt(points[2]), endY = parseInt(points[3]);
stdArgStr += ((Math.atan2(endY- startY, endX - startX)) * (180 / Math.PI)+90) + 'deg';
}else{
if(points[1] === points[3]){ // both 'top' or 'bottom, this linear gradient goes left-right
stdArgStr += 'to ' + points[2];
}else if(points[0] === points[2]){ // both 'left' or 'right', this linear gradient goes top-bottom
stdArgStr += 'to ' + points[3];
}else if(points[1] === 'top'){ // diagonal gradient - from top left to opposite corner is 135deg
stdArgStr += '135deg';
}else{
stdArgStr += '45deg';
}
}
}else if(/^radial/i.test(type)){ // oooh, radial gradients..
stdArgStr += 'circle ' + args[3].name.replace(/(\d+)$/, '$1px') + ' at ' + args[0].name.replace(/(\d+) /, '$1px ').replace(/(\d+)$/, '$1px');
}
var toColor;
for(var j = type === 'linear' ? 2 : 4; j < args.length; j++){
var position, color, colorIndex;
if(args[j].name === 'color-stop'){
position = args[j].args[0].name;
colorIndex = 1;
}else if (args[j].name === 'to') {
position = '100%';
colorIndex = 0;
}else if (args[j].name === 'from') {
position = '0%';
colorIndex = 0;
};
if (position.indexOf('%') === -1) { // original Safari syntax had 0.5 equivalent to 50%
position = (parseFloat(position) * 100) +'%';
};
color = args[j].args[colorIndex].name;
if (args[j].args[colorIndex].args) { // the color is itself a function call, like rgb()
color += '(' + this.colorValue(args[j].args[colorIndex].args) + ')';
};
if (args[j].name === 'from'){
stops.unshift(color + ' ' + position);
}else if(args[j].name === 'to'){
toColor = color;
}else{
stops.push(color + ' ' + position);
}
}
// translating values to right syntax
for(var j = 0; j < stops.length; j++){
stdArgStr += ', ' + stops[j];
}
if(toColor){
stdArgStr += ', ' + toColor + ' 100%';
}
return stdArgStr;
},
colorValue: function(obj){
var ar = [];
for (var i = 0; i < obj.length; i++) {
ar.push(obj[i].name);
};
return ar.join(', ');
},
};
this.NSGetFactory = XPCOMUtils.generateNSGetFactory([CSSUnprefixingService]);