Function attachDoc

static/plugins/codemirror/codemirror.js:4823–4834

(cm, doc)

  // Attach a document to an editor.
  function attachDoc(cm, doc) {
    if (doc.cm) { throw new Error("This document is already in use.") }
    cm.doc = doc;
    doc.cm = cm;
    estimateLineHeights(cm);
    loadMode(cm);
    setDirectionClass(cm);
    cm.options.direction = doc.direction;
    if (!cm.options.lineWrapping) { findMaxLine(cm); }
    cm.options.mode = doc.modeOption;
    regChange(cm);
  }

  function setDirectionClass(cm) {
  (cm.doc.direction == "rtl" ? addClass : rmClass)(cm.display.lineDiv, "CodeMirror-rtl");