User:Quarl/diff.js

// User:Quarl/diff.js - utility functions for doing diffs

// quarl 2006-01-29 initial version

// requires: util.js (trimspaces)

//

// if more than this many words of changes, use overflow string var diff_wikisummary_maxwords = 30; var diff_wikisummary_overflow = "$1 words changed";

/* * diff and diffString are based on * http://ejohn.org/projects/javascript-diff-algorithm/ *  Copyright John Resig */

function diff_split(s) { //return trimspaces(s).split(/(?:\s|[.,;\'\"`])+/);   return trimspaces(s).split(/\s+/); }

function diffString( o, n ) { var out = diff( diff_split(o), diff_split(n) ); var str = "";

for ( var i = 0; i < out.n.length - 1; i++ ) { if ( out.n[i].text == null ) { if ( out.n[i].indexOf('"') == -1 && out.n[i].indexOf('<') == -1 )               str += " " + out.n[i] +" ";            else                str += " " + out.n[i];        } else {            var pre = "";            if ( out.n[i].text.indexOf('"') == -1 && out.n[i].text.indexOf('<') == -1 ) {

var n = out.n[i].row + 1; while ( n < out.o.length && out.o[n].text == null ) { if ( out.o[n].indexOf('"') == -1 && out.o[n].indexOf('<') == -1 && out.o[n].indexOf(':') == -1 && out.o[n].indexOf(';') == -1 )                       pre += " " + out.o[n] +" ";                    n++;                }            }            str += " " + out.n[i].text + pre;        }    }

return str; }

function diff( o, n ) { var ns = {}; var os = {};

for ( var i = 0; i < n.length; i++ ) { // note we have to check that it is in fact an object with "rows", in       // case ns[i] happens to match a javascript member function of class // Array, e.g. "some"! if ( ns[ n[i] ] == null || !ns[n[i]].rows ) ns[ n[i] ] = { rows: new Array, o: null }; ns[ n[i] ].rows.push( i ); }

for ( var i = 0; i < o.length; i++ ) { if ( os[ o[i] ] == null || !os[o[i]].rows ) os[ o[i] ] = { rows: new Array, n: null }; os[ o[i] ].rows.push( i ); }

for ( var i in ns ) { if ( ns[i].rows.length == 1 && typeof(os[i]) != "undefined" && os[i].rows.length == 1 ) { n[ ns[i].rows[0] ] = { text: n[ ns[i].rows[0] ], row: os[i].rows[0] }; o[ os[i].rows[0] ] = { text: o[ os[i].rows[0] ], row: ns[i].rows[0] }; }   }

for ( var i = 0; i < n.length - 1; i++ ) { if ( n[i].text != null && n[i+1].text == null &&            0 <= n[i].row+1 && n[i].row+1 < o.length &&             o[ n[i].row + 1 ].text == null &&             n[i+1] == o[ n[i].row + 1 ] ) {           n[i+1] = { text: n[i+1], row: n[i].row + 1 }; o[n[i].row+1] = { text: o[n[i].row+1], row: i + 1 }; }   }

for ( var i = n.length - 1; i > 0; i-- ) { if ( n[i].text != null && n[i-1].text == null &&            0 <= n[i].row-1 && n[i].row-1 < o.length &&             o[ n[i].row - 1 ].text == null &&             n[i-1] == o[ n[i].row - 1 ] ) {           n[i-1] = { text: n[i-1], row: n[i].row - 1 }; o[n[i].row-1] = { text: o[n[i].row-1], row: i - 1 }; }   }

return { o: o, n: n }; }

function diffAggregate(words) { var phrases = new Array; var cur = null; var wordcount = 0;

// start at virtual index -1 to check for removed words at beginning of   // text for ( var i = -1; i < words.n.length; i++ ) { if ( i!=-1 && words.n[i].text == null ) { if (!cur) { cur = { o: "", n: "" }; phrases.push(cur); }           cur.n += " " + words.n[i]; wordcount ++; } else { var pre = ""; var j = i==-1 ? 0 : words.n[i].row + 1; while ( j < words.o.length && words.o[j].text == null ) { pre += " " + words.o[j]; j++; wordcount ++; }           if (pre) { if (!cur) { cur = { o: "", n: "" }; phrases.push(cur); }               cur.o += pre; }           if (pre && words.n[i+1] && words.n[i+1].text == null) { // If there's an addition following, treat this as part of the // same change. } else { cur = null; }       }    }

for (var i in phrases) { phrases[i].n = trimspaces(phrases[i].n); phrases[i].o = trimspaces(phrases[i].o); }

return { phrases: phrases, wordcount: wordcount }; }

function diffWikiQuote(s) { if (!s) return s;   if (s.match(/^\{\{.*\}\}$/)) return s;    s = s.replace(/\"/g, "'");    return '"'+s+'"'; }

function reverse(s) { var ret = ''; for (var i = s.length-1; i >= 0; --i) { ret += s[i]; }   return ret; }

// trim the equal chars from the front and back of o,n at a word boundary function diffStringTrim(o, n) { var r = diffStringTrim0(reverse(o), reverse(n)); return diffStringTrim0(reverse(r.o), reverse(r.n)); }

function diffStringTrim0(o, n) { var i = 0; while (i < o.length && i < n.length && o[i] == n[i]) { ++i; }

// find index of last non-word character var prefix = o.substr(0, i);

// if prefix ends with word characters and suffix starts with non-word, // then erase entire prefix if (prefix.match(/\w$/) &&       !o.substr(i, 1).match(/^\w/) && !n.substr(i, 1).match(/^\w/)) {       o = o.substr(i); n = n.substr(i); } else if (prefix.match(/.*\W/)) { i = RegExp.lastMatch.length; o = o.substr(i); n = n.substr(i); } else { // keep entire prefix }   return { o: o, n: n }; }

function diffSummary(o, n) { if (o == n) return ""; if (!o) return "new"; if (!n) return "blank"; var words = diff( diff_split(o), diff_split(n) ); var r = diffAggregate(words); if (!r.wordcount) return ""; if (r.wordcount > diff_wikisummary_maxwords) { return diff_wikisummary_overflow.replace('$1', r.wordcount); }

var phrases = r.phrases; var str = []; for (var i in phrases) { var r = diffStringTrim(phrases[i].o, phrases[i].n); var o = diffWikiQuote(r.o), n = diffWikiQuote(r.n); if (o && n) { str.push(o + ' → ' + n); } else if (o) { str.push('-' + o); } else if (n) { str.push('+' + n); } else { alert("## internal error 15e1b13f-bae3-4399-86c5-721786822fa2"); }   }

return str.join(", "); }

//