Function updateLineBackground

static/libs/codemirror.js:2185–2196

(cm, lineView)

}

function updateLineBackground(cm, lineView) {
  var cls = lineView.bgClass ? lineView.bgClass + " " + (lineView.line.bgClass || "") : lineView.line.bgClass;
  if (cls) { cls += " CodeMirror-linebackground"; }
  if (lineView.background) {
    if (cls) { lineView.background.className = cls; }
    else { lineView.background.parentNode.removeChild(lineView.background); lineView.background = null; }
  } else if (cls) {
    var wrap = ensureLineWrapped(lineView);
    lineView.background = wrap.insertBefore(elt("div", null, cls), wrap.firstChild);
    cm.display.input.setUneditable(lineView.background);
  }
}

// Wrapper around buildLineContent which will reuse the structure
// in display.externalMeasured when possible.