Function highlightLine

samples/common/codehighlight/codemirror.js:1066–1109

(cm, line, context, forceToEnd)

  // style strings), which is used to highlight the tokens on the
  // line.
  function highlightLine(cm, line, context, forceToEnd) {
    // A styles array always starts with a number identifying the
    // mode/overlays that it is based on (for easy invalidation).
    var st = [cm.state.modeGen], lineClasses = {};
    // Compute the base array of styles
    runMode(cm, line.text, cm.doc.mode, context, function (end, style) { return st.push(end, style); },
            lineClasses, forceToEnd);
    var state = context.state;

    // Run overlays, adjust style array.
    var loop = function ( o ) {
      context.baseTokens = st;
      var overlay = cm.state.overlays[o], i = 1, at = 0;
      context.state = true;
      runMode(cm, line.text, overlay.mode, context, function (end, style) {
        var start = i;
        // Ensure there's a token end at the current position, and that i points at it
        while (at < end) {
          var i_end = st[i];
          if (i_end > end)
            { st.splice(i, 1, end, st[i+1], i_end); }
          i += 2;
          at = Math.min(end, i_end);
        }
        if (!style) { return }
        if (overlay.opaque) {
          st.splice(start, i - start, end, "overlay " + style);
          i = start + 2;
        } else {
          for (; start < i; start += 2) {
            var cur = st[start+1];
            st[start+1] = (cur ? cur + " " : "") + "overlay " + style;
          }
        }
      }, lineClasses);
      context.state = state;
      context.baseTokens = null;
      context.baseTokenPos = 1;
    };

    for (var o = 0; o < cm.state.overlays.length; ++o) loop( o );

    return {styles: st, classes: lineClasses.bgClass || lineClasses.textClass ? lineClasses : null}
  }

  function getLineStyles(cm, line, updateFrontier) {
    if (!line.styles || line.styles[0] != cm.state.modeGen) {