text: ﻿// Because sometimes you need to style the cursor's line.
  //
  // Adds an option 'styleActiveLine' which, when enabled, gives the
  // active line's wrapping <div> the CSS class "CodeMirror-activeline",
  // and gives its background <div> the class "CodeMirror-activeline-background".
  
  (function() {
    "use strict";
    var WRAP_CLASS = "CodeMirror-activeline";
    var BACK_CLASS = "CodeMirror-activeline-background";
  
    CodeMirror.defineOption("styleActiveLine", false, function(cm, val, old) {
      var prev = old && old != CodeMirror.Init;
      if (val && !prev) {
        updateActiveLine(cm);
        cm.on("cursorActivity", updateActiveLine);
      } else if (!val && prev) {
        cm.off("cursorActivity", updateActiveLine);
        clearActiveLine(cm);
        delete cm.state.activeLine;
      }
    });
  
    function clearActiveLine(cm) {
      if ("activeLine" in cm.state) {
        cm.removeLineClass(cm.state.activeLine, "wrap", WRAP_CLASS);
        cm.removeLineClass(cm.state.activeLine, "background", BACK_CLASS);
      }
    }
  
    function updateActiveLine(cm) {
      var line = cm.getLineHandle(cm.getCursor().line);
      if (cm.state.activeLine == line) return;
      clearActiveLine(cm);
      cm.addLineClass(line, "wrap", WRAP_CLASS);
      cm.addLineClass(line, "background", BACK_CLASS);
      cm.state.activeLine = line;
    }
  })();
  