src/BufferSet.ts

   1 /**
   2  * @license MIT
   3  */
   4
   5 import { ITerminal, IBufferSet } from './Interfaces';
   6 import { Buffer } from './Buffer';
   7 import { EventEmitter } from './EventEmitter';
   8
   9 /**
  10  * The BufferSet represents the set of two buffers used by xterm terminals (normal and alt) and
  11  * provides also utilities for working with them.
  12  */
  13 export class BufferSet extends EventEmitter implements IBufferSet {
  14   private _normal: Buffer;
  15   private _alt: Buffer;
  16   private _activeBuffer: Buffer;
  17
  18   /**
  19    * Create a new BufferSet for the given terminal.
  20    * @param {Terminal} terminal - The terminal the BufferSet will belong to
  21    */
  22   constructor(private _terminal: ITerminal) {
  23     super();
  24     this._normal = new Buffer(this._terminal);
  25     this._normal.fillViewportRows();
  26     this._alt = new Buffer(this._terminal);
  27     this._activeBuffer = this._normal;
  28   }
  29
  30   /**
  31    * Returns the alt Buffer of the BufferSet
  32    * @returns {Buffer}
  33    */
  34   public get alt(): Buffer {
  35     return this._alt;
  36   }
  37
  38   /**
  39    * Returns the normal Buffer of the BufferSet
  40    * @returns {Buffer}
  41    */
  42   public get active(): Buffer {
  43     return this._activeBuffer;
  44   }
  45
  46   /**
  47    * Returns the currently active Buffer of the BufferSet
  48    * @returns {Buffer}
  49    */
  50   public get normal(): Buffer {
  51     return this._normal;
  52   }
  53
  54   /**
  55    * Sets the normal Buffer of the BufferSet as its currently active Buffer
  56    */
  57   public activateNormalBuffer(): void {
  58     // The alt buffer should always be cleared when we switch to the normal
  59     // buffer. This frees up memory since the alt buffer should always be new
  60     // when activated.
  61     this._alt.clear();
  62
  63     this._activeBuffer = this._normal;
  64     this.emit('activate', this._normal);
  65   }
  66
  67   /**
  68    * Sets the alt Buffer of the BufferSet as its currently active Buffer
  69    */
  70   public activateAltBuffer(): void {
  71     // Since the alt buffer is always cleared when the normal buffer is
  72     // activated, we want to fill it when switching to it.
  73     this._alt.fillViewportRows();
  74
  75     this._activeBuffer = this._alt;
  76     this.emit('activate', this._alt);
  77   }
  78
  79   /**
  80    * Resizes both normal and alt buffers, adjusting their data accordingly.
  81    * @param newCols The new number of columns.
  82    * @param newRows The new number of rows.
  83    */
  84   public resize(newCols: number, newRows: number): void {
  85     this._normal.resize(newCols, newRows);
  86     this._alt.resize(newCols, newRows);
  87   }
  88 }