1  const { Emitter } = require('event-kit');
  2  
  3  const DefaultPriority = -100;
  4  
  5  // Extended: Represents a gutter within a {TextEditor}.
  6  //
  7  // See {TextEditor::addGutter} for information on creating a gutter.
  8  module.exports = class Gutter {
  9    constructor(gutterContainer, options) {
 10      this.gutterContainer = gutterContainer;
 11      this.name = options && options.name;
 12      this.priority =
 13        options && options.priority != null ? options.priority : DefaultPriority;
 14      this.visible = options && options.visible != null ? options.visible : true;
 15      this.type = options && options.type != null ? options.type : 'decorated';
 16      this.labelFn = options && options.labelFn;
 17      this.className = options && options.class;
 18  
 19      this.onMouseDown = options && options.onMouseDown;
 20      this.onMouseMove = options && options.onMouseMove;
 21  
 22      this.emitter = new Emitter();
 23    }
 24  
 25    /*
 26    Section: Gutter Destruction
 27    */
 28  
 29    // Essential: Destroys the gutter.
 30    destroy() {
 31      if (this.name === 'line-number') {
 32        throw new Error('The line-number gutter cannot be destroyed.');
 33      } else {
 34        this.gutterContainer.removeGutter(this);
 35        this.emitter.emit('did-destroy');
 36        this.emitter.dispose();
 37      }
 38    }
 39  
 40    /*
 41    Section: Event Subscription
 42    */
 43  
 44    // Essential: Calls your `callback` when the gutter's visibility changes.
 45    //
 46    // * `callback` {Function}
 47    //  * `gutter` The gutter whose visibility changed.
 48    //
 49    // Returns a {Disposable} on which `.dispose()` can be called to unsubscribe.
 50    onDidChangeVisible(callback) {
 51      return this.emitter.on('did-change-visible', callback);
 52    }
 53  
 54    // Essential: Calls your `callback` when the gutter is destroyed.
 55    //
 56    // * `callback` {Function}
 57    //
 58    // Returns a {Disposable} on which `.dispose()` can be called to unsubscribe.
 59    onDidDestroy(callback) {
 60      return this.emitter.once('did-destroy', callback);
 61    }
 62  
 63    /*
 64    Section: Visibility
 65    */
 66  
 67    // Essential: Hide the gutter.
 68    hide() {
 69      if (this.visible) {
 70        this.visible = false;
 71        this.gutterContainer.scheduleComponentUpdate();
 72        this.emitter.emit('did-change-visible', this);
 73      }
 74    }
 75  
 76    // Essential: Show the gutter.
 77    show() {
 78      if (!this.visible) {
 79        this.visible = true;
 80        this.gutterContainer.scheduleComponentUpdate();
 81        this.emitter.emit('did-change-visible', this);
 82      }
 83    }
 84  
 85    // Essential: Determine whether the gutter is visible.
 86    //
 87    // Returns a {Boolean}.
 88    isVisible() {
 89      return this.visible;
 90    }
 91  
 92    // Essential: Add a decoration that tracks a {DisplayMarker}. When the marker moves,
 93    // is invalidated, or is destroyed, the decoration will be updated to reflect
 94    // the marker's state.
 95    //
 96    // ## Arguments
 97    //
 98    // * `marker` A {DisplayMarker} you want this decoration to follow.
 99    // * `decorationParams` An {Object} representing the decoration. It is passed
100    //   to {TextEditor::decorateMarker} as its `decorationParams` and so supports
101    //   all options documented there.
102    //   * `type` __Caveat__: set to `'line-number'` if this is the line-number
103    //     gutter, `'gutter'` otherwise. This cannot be overridden.
104    //
105    // Returns a {Decoration} object
106    decorateMarker(marker, options) {
107      return this.gutterContainer.addGutterDecoration(this, marker, options);
108    }
109  
110    getElement() {
111      if (this.element == null) this.element = document.createElement('div');
112      return this.element;
113    }
114  };