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/**
* Functions for showing the difference between two strings
*
* Taken from the popups gadget and modified for re-use as
* a module for other gadgets.
*
* Source: https://en.wikipedia.org/wiki/MediaWiki:Gadget-popups.js
*
* Access by loading then through the inductiveload.difference
* object:
*
* mw.loader.using(["ext.gadget.util-difference"], function() {
* // code that uses this module
* });
*
* Methods:
*
* * diffString: get the complete diff string between two strings
* * shortenDiffString: shorten a given diff string with 'n' chars
* of context
*/
"use strict";
// IIFE used when including as a user script (to allow debug or config)
// Default gadget use will get an IIFE wrapper as well
(function() {
window.inductiveload = window.inductiveload || {}; // use window for ResourceLoader compatibility
if (inductiveload.difference) {
return; // already initialised, don't overwrite
}
function delFmt(x) {
if (!x.length) { return ''; }
return "<del class='popupDiff'>" + x.join('') +"</del>";
}
function insFmt(x) {
if (!x.length) { return ''; }
return "<ins class='popupDiff'>" + x.join('') +"</ins>";
}
function countCrossings(a, b, i, eject) {
// count the crossings on the edge starting at b[i]
if (!b[i].row && b[i].row !== 0) { return -1; }
var count=0;
for (var j=0; j<a.length; ++j) {
if (!a[j].row && a[j].row !== 0) { continue; }
if ( (j-b[i].row)*(i-a[j].row) > 0) {
if(eject) { return true; }
count++;
}
}
return count;
}
var entify = function(s) {
//var shy='­';
return s.split('&').join('&').split('<').join('<').split('>').join('>'/*+shy*/).split('"').join('"');
};
// see http://developer.mozilla.org/en/docs/Core_JavaScript_1.5_Reference:Global_Objects:Object
// FIXME: use obj.hasOwnProperty instead of this kludge!
var jsReservedProperties=RegExp('^(constructor|prototype|__((define|lookup)[GS]etter)__' +
'|eval|hasOwnProperty|propertyIsEnumerable' +
'|to(Source|String|LocaleString)|(un)?watch|valueOf)$');
function diffBugAlert(word) {
if (!diffBugAlert.list[word]) {
diffBugAlert.list[word]=1;
alert('Bad word: '+word+'\n\nPlease report this bug.');
}
}
diffBugAlert.list={};
function makeDiffHashtable(src) {
var ret={};
for ( var i = 0; i < src.length; i++ ) {
if ( jsReservedProperties.test(src[i]) ) { src[i] += '<!-- -->'; }
if ( !ret[ src[i] ] ) { ret[ src[i] ] = []; }
try { ret[ src[i] ].push( i ); } catch (err) { diffBugAlert(src[i]); }
}
return ret;
}
function diff( o, n ) {
// pass 1: make hashtable ns with new rows as keys
var ns = makeDiffHashtable(n);
// pass 2: make hashtable os with old rows as keys
var os = makeDiffHashtable(o);
// pass 3: pair unique new rows and matching unique old rows
var i;
for ( i in ns ) {
if ( ns[i].length == 1 && os[i] && os[i].length == 1 ) {
n[ ns[i][0] ] = { text: n[ ns[i][0] ], row: os[i][0], paired: true };
o[ os[i][0] ] = { text: o[ os[i][0] ], row: ns[i][0], paired: true };
}
}
// pass 4: pair matching rows immediately following paired rows (not necessarily unique)
for ( i = 0; i < n.length - 1; i++ ) {
if ( n[i].paired && ! n[i+1].paired && n[i].row + 1 < o.length && ! o[ n[i].row + 1 ].paired &&
n[i+1] == o[ n[i].row + 1 ] ) {
n[i+1] = { text: n[i+1], row: n[i].row + 1, paired: true };
o[n[i].row+1] = { text: o[n[i].row+1], row: i + 1, paired: true };
}
}
// pass 5: pair matching rows immediately preceding paired rows (not necessarily unique)
for ( i = n.length - 1; i > 0; i-- ) {
if ( n[i].paired && ! n[i-1].paired && n[i].row > 0 && ! o[ n[i].row - 1 ].paired &&
n[i-1] == o[ n[i].row - 1 ] ) {
n[i-1] = { text: n[i-1], row: n[i].row - 1, paired: true };
o[n[i].row-1] = { text: o[n[i].row-1], row: i - 1, paired: true };
}
}
return { o: o, n: n };
}
inductiveload.difference = {
/**
* Given a complete diff string, produce a shortened string with
* a certain number of characters of context around the differences.
* @param {string} str the complete diff string
* @param {number} context number of context chars
* @return {string} shortened diff string
*/
shortenDiffString: function(str, context) {
var re=RegExp('(<del[\\s\\S]*?</del>|<ins[\\s\\S]*?</ins>)');
var splitted=str.split(re);
var ret=[''];
for (var i=0; i<splitted.length; i+=2) {
if (splitted[i].length < 2*context) {
ret[ret.length-1] += splitted[i];
if (i+1<splitted.length) { ret[ret.length-1] += splitted[i+1]; }
continue;
}
else {
if (i > 0) { ret[ret.length-1] += splitted[i].substring(0,context); }
if (i+1 < splitted.length) {
ret.push(splitted[i].substring(splitted[i].length-context) +
splitted[i+1]);
}
}
}
while (ret.length > 0 && !ret[0]) { ret = ret.slice(1); }
return ret;
},
/**
* Produce a complete difference string from two strings (old and new)
* @param {string} o old string
* @param {string} n new string
* @param {bool} simpleSplit use a simple split method
* @return {string} the difference string
*/
diffString: function( o, n, simpleSplit ) {
var splitRe=RegExp('([[]{2}|[\\]]{2}|[{]{2,3}|[}]{2,3}|[|]|=|<|>|[*:]+|\\s|\\b)');
// We need to split the strings o and n first, and entify() the parts
// individually, so that the HTML entities are never cut apart. (AxelBoldt)
var out, i, oSplitted, nSplitted;
if (simpleSplit) {
oSplitted=o.split(/\b/);
nSplitted=n.split(/\b/);
} else {
oSplitted=o.split(splitRe);
nSplitted=n.split(splitRe);
}
for (i=0; i<oSplitted.length; ++i) {oSplitted[i]=entify(oSplitted[i]);}
for (i=0; i<nSplitted.length; ++i) {nSplitted[i]=entify(nSplitted[i]);}
out = diff (oSplitted, nSplitted);
var str = "";
var acc=[]; // accumulator for prettier output
// crossing pairings -- eg 'A B' vs 'B A' -- cause problems, so let's iron them out
// this doesn't always do things optimally but it should be fast enough
var maxOutputPair=0;
for (i=0; i<out.n.length; ++i) {
if ( out.n[i].paired ) {
if( maxOutputPair > out.n[i].row ) {
// tangle - delete pairing
out.o[ out.n[i].row ]=out.o[ out.n[i].row ].text;
out.n[i]=out.n[i].text;
}
if (maxOutputPair < out.n[i].row) { maxOutputPair = out.n[i].row; }
}
}
// output the stuff preceding the first paired old line
for (i=0; i<out.o.length && !out.o[i].paired; ++i) { acc.push( out.o[i] ); }
str += delFmt(acc); acc=[];
// main loop
for ( i = 0; i < out.n.length; ++i ) {
// output unpaired new "lines"
while ( i < out.n.length && !out.n[i].paired ) { acc.push( out.n[i++] ); }
str += insFmt(acc); acc=[];
if ( i < out.n.length ) { // this new "line" is paired with the (out.n[i].row)th old "line"
str += out.n[i].text;
// output unpaired old rows starting after this new line's partner
var m = out.n[i].row + 1;
while ( m < out.o.length && !out.o[m].paired ) { acc.push ( out.o[m++] ); }
str += delFmt(acc); acc=[];
}
}
return str;
},
};
}());