User:Splarka/diffpreloader.js

/* Difference preloader checker thingy, version [0.0.0]
Originally from: http://en.wikipedia.org/wiki/User:Splarka/diffpreloader.js

Pre-fetches diff links to see if they're too big. Some diffs are really big! 
Styles the link indicating the size (more or less than threshhold bytes of diff table html).

Notes:
* Currently only works with oldid= parameter present.
** It is feasable to do it with title= parameter or wgArticlePath match, but this would be a lot of work.
* Currently doesn't load in the main namespace on view actions, this is to prevent excessive javascripting.
* Custom user definitions:
* Style (small/big) threshhold: "var diffPreloaderThreshhold = integer" (default 100000).
* Text of sibling link: "var diffPreloaderSibling = string" (default false, uses diff link instead).
* Your own styles: "var diffPreloaderStyle = [unknown,checking,small,big]".

To do:
* Should there be an auto-go option? 
** Using document.location.href ruins browser navigation history in many browsers, meh. 
* Should there be an alert option? 
* Should there be a "check all" button?
*/

if(!window.diffPreloaderStyle) var diffPreloaderStyle = ['color:#ffffff;background-color:#000000;','background-color:#eeee00;','background-color:#00ff00;','background-color:#ff0000;'];
if(!window.diffPreloaderSibling) var diffPreloaderSibling = false
if(!window.diffPreloaderThreshhold) var diffPreloaderThreshhold = 100000

function diffPreloader() {
  var docobj = document.getElementById('bodyContent') || document.getElementById('content') || document.body;
  var a = docobj.getElementsByTagName('a');
  if(!a) return
  var ds = diffPreloaderStyle;
  var siblink = diffPreloaderSibling || false;
  appendCSS('.diffPreload-new {' + ds[0] + '} .diffPreload-loading {' + ds[1] + '} .diffPreload-small {' + ds[2] + '} .diffPreload-big {' + ds[3] + '} ');

  for(var i=a.length-1;i>=0;i--) {
    var href = a[i].getAttribute('href',2);
    if(!href) continue
    var diffr = /diff\=(next|prev|[\d]*)/i;
    var oldidr = /oldid\=(\d*)/i;

    if(diffr.test(href) && oldidr.test(href)) {
      var as;
      if(!siblink) {
        as = a[i];
      } else {
        var small = document.createElement('small');
        var sib = document.createElement('a');
        as = sib;
        sib.appendChild(document.createTextNode(siblink));
        small.appendChild(document.createTextNode(' ('));
        small.appendChild(sib)
        small.appendChild(document.createTextNode(')'));
        insertAfter(small,a[i]);
      }
      as.className += ' diffPreload-new';
      as.setAttribute('id','diffPreload-' + i);
      as.setAttribute('alt',href);
      as.setAttribute('href','javascript:diffPreloaderClick(' + i + ',"' + href.match(diffr)[1] + '","' + href.match(oldidr)[1] + '");');
    }
  }
}
if(wgAction != 'view'|| wgNamespaceNumber != 0 || queryString('diff')) addOnloadHook(diffPreloader)

function diffPreloaderClick(aid,diff,oldid) {
  var a = document.getElementById('diffPreload-' + aid);
  a.setAttribute('class',a.getAttribute('class').replace(/diffPreload\-new/ig,'diffPreload-loading'))
  var url = wgScriptPath + '/api.php?maxage=86400&smaxage=86400&action=query&requestid=' + aid + '&indexpageids&format=json&callback=diffPreloaderCB&prop=revisions&rvprop=size&revids=' + oldid + '&rvdiffto=' + diff;
  mw.loader.load(url);
}

function diffPreloaderCB(obj) {
  if(obj['error']) alert('Api error in diff preloader: ' + obj['error']['code'] + '\n' + obj['error']['info'])
  if(!obj['requestid'] || !obj['query'] || !obj['query']['pages'] || !obj['query']['pageids']) return
  var a = document.getElementById('diffPreload-' + obj['requestid']);
  var revs = obj['query']['pages'][obj['query']['pageids'][0]]['revisions'];
  if(!revs || revs.length == 0 || !revs[0]['diff'] || !revs[0]['diff']['*']) return
  var length = revs[0]['diff']['*'].length;
  var size = revs[0]['size'] || 0;
  if(length < diffPreloaderThreshhold) {
    var aclass = 'diffPreload-small';
  } else {
    var aclass = 'diffPreload-big';
  }
  a.setAttribute('class',a.getAttribute('class').replace(/diffPreload\-loading/ig,aclass));
  a.setAttribute('href',a.getAttribute('alt'));
}

function queryString(p) {
  var re = RegExp('[&?]' + p + '=([^&]*)');
  var matches;
  if (matches = re.exec(document.location)) {
    try { 
      return decodeURI(matches[1]);
    } catch (e) {
    }
  }
  return null;
}

function insertAfter(nn,ref) {
  if(ref.nextSibling) {
    ref.parentNode.insertBefore(nn,ref.nextSibling);
  } else {
    ref.parentNode.appendChild(nn);
  }
}