Function doFold

static/editor.md/lib/codemirror/addon/fold/foldcode.js:14–59

(cm, pos, options, force)

  "use strict";

  function doFold(cm, pos, options, force) {
    if (options && options.call) {
      var finder = options;
      options = null;
    } else {
      var finder = getOption(cm, options, "rangeFinder");
    }
    if (typeof pos == "number") pos = CodeMirror.Pos(pos, 0);
    var minSize = getOption(cm, options, "minFoldSize");

    function getRange(allowFolded) {
      var range = finder(cm, pos);
      if (!range || range.to.line - range.from.line < minSize) return null;
      var marks = cm.findMarksAt(range.from);
      for (var i = 0; i < marks.length; ++i) {
        if (marks[i].__isFold && force !== "fold") {
          if (!allowFolded) return null;
          range.cleared = true;
          marks[i].clear();
        }
      }
      return range;
    }

    var range = getRange(true);
    if (getOption(cm, options, "scanUp")) while (!range && pos.line > cm.firstLine()) {
      pos = CodeMirror.Pos(pos.line - 1, 0);
      range = getRange(false);
    }
    if (!range || range.cleared || force === "unfold") return;

    var myWidget = makeWidget(cm, options);
    CodeMirror.on(myWidget, "mousedown", function(e) {
      myRange.clear();
      CodeMirror.e_preventDefault(e);
    });
    var myRange = cm.markText(range.from, range.to, {
      replacedWith: myWidget,
      clearOnEnter: true,
      __isFold: true
    });
    myRange.on("clear", function(from, to) {
      CodeMirror.signal(cm, "unfold", cm, from, to);
    });
    CodeMirror.signal(cm, "fold", cm, range.from, range.to);
  }

  function makeWidget(cm, options) {
    var widget = getOption(cm, options, "widget");