Function highlightWorker

static/editor.md/lib/codemirror/lib/codemirror.js:2334–2369

(cm)

  }

  function highlightWorker(cm) {
    var doc = cm.doc;
    if (doc.frontier < doc.first) doc.frontier = doc.first;
    if (doc.frontier >= cm.display.viewTo) return;
    var end = +new Date + cm.options.workTime;
    var state = copyState(doc.mode, getStateBefore(cm, doc.frontier));
    var changedLines = [];

    doc.iter(doc.frontier, Math.min(doc.first + doc.size, cm.display.viewTo + 500), function(line) {
      if (doc.frontier >= cm.display.viewFrom) { // Visible
        var oldStyles = line.styles;
        var highlighted = highlightLine(cm, line, state, true);
        line.styles = highlighted.styles;
        var oldCls = line.styleClasses, newCls = highlighted.classes;
        if (newCls) line.styleClasses = newCls;
        else if (oldCls) line.styleClasses = null;
        var ischange = !oldStyles || oldStyles.length != line.styles.length ||
          oldCls != newCls && (!oldCls || !newCls || oldCls.bgClass != newCls.bgClass || oldCls.textClass != newCls.textClass);
        for (var i = 0; !ischange && i < oldStyles.length; ++i) ischange = oldStyles[i] != line.styles[i];
        if (ischange) changedLines.push(doc.frontier);
        line.stateAfter = copyState(doc.mode, state);
      } else {
        processLine(cm, line.text, state);
        line.stateAfter = doc.frontier % 5 == 0 ? copyState(doc.mode, state) : null;
      }
      ++doc.frontier;
      if (+new Date > end) {
        startWorker(cm, cm.options.workDelay);
        return true;
      }
    });
    if (changedLines.length) runInOp(cm, function() {
      for (var i = 0; i < changedLines.length; i++)
        regLineChange(cm, changedLines[i], "text");
    });
  }

  // Finds the line to start with when starting a parse. Tries to
  // find a line with a stateAfter, so that it can start with a