SerializeAddon.ts

import { Terminal, ITerminalAddon } from 'xterm';

export const enum Attributes {
  /**
   * bit 1..8     blue in RGB, color in P256 and P16
   */
  BLUE_MASK = 0xFF,
  BLUE_SHIFT = 0,
  PCOLOR_MASK = 0xFF,
  PCOLOR_SHIFT = 0,

  /**
   * bit 9..16    green in RGB
   */
  GREEN_MASK = 0xFF00,
  GREEN_SHIFT = 8,

  /**
   * bit 17..24   red in RGB
   */
  RED_MASK = 0xFF0000,
  RED_SHIFT = 16,

  /**
   * bit 25..26   color mode: DEFAULT (0) | P16 (1) | P256 (2) | RGB (3)
   */
  CM_MASK = 0x3000000,
  CM_DEFAULT = 0,
  CM_P16 = 0x1000000,
  CM_P256 = 0x2000000,
  CM_RGB = 0x3000000,

  /**
   * bit 1..24  RGB room
   */
  RGB_MASK = 0xFFFFFF
}

export const enum FgFlags {
  /**
   * bit 27..31 (32th bit unused)
   */
  INVERSE = 0x4000000,
  BOLD = 0x8000000,
  UNDERLINE = 0x10000000,
  BLINK = 0x20000000,
  INVISIBLE = 0x40000000
}

export const enum BgFlags {
  /**
   * bit 27..32 (upper 4 unused)
   */
  ITALIC = 0x4000000,
  DIM = 0x8000000
}

export class SerializeAddon implements ITerminalAddon {
  private _terminal: Terminal|undefined = undefined;
  public dispose(): void {}
  public activate(terminal: Terminal): void {
    this._terminal = terminal;
  }

  private _extractAttributes(oldCell: any, newCell: any): string {
    const switches: number[] = [];
    if (oldCell.fg !== newCell.fg) {
      // flags
      if ((oldCell.fg & FgFlags.INVERSE) !== (newCell.fg & FgFlags.INVERSE)) {
        switches.push(newCell.fg & FgFlags.INVERSE ? 7 : 27);
      }
      if ((oldCell.fg & FgFlags.BOLD) !== (newCell.fg & FgFlags.BOLD)) {
        switches.push(newCell.fg & FgFlags.BOLD ? 1 : 22);
      }
      if ((oldCell.fg & FgFlags.UNDERLINE) !== (newCell.fg & FgFlags.UNDERLINE)) {
        switches.push(newCell.fg & FgFlags.UNDERLINE ? 4 : 24);
      }
      if ((oldCell.fg & FgFlags.BLINK) !== (newCell.fg & FgFlags.BLINK)) {
        switches.push(newCell.fg & FgFlags.BLINK ? 5 : 25);
      }
      if ((oldCell.fg & FgFlags.INVISIBLE) !== (newCell.fg & FgFlags.INVISIBLE)) {
        switches.push(newCell.fg & FgFlags.INVISIBLE ? 8 : 28);
      }
      // colors
      if ((oldCell.fg & (Attributes.CM_MASK | Attributes.RGB_MASK)) !== (newCell.fg & (Attributes.CM_MASK | Attributes.RGB_MASK))) {
        switch (newCell.fg & Attributes.CM_MASK) {
          case Attributes.CM_P16:
            switches.push(newCell.fg & 8 ? 90 + (newCell.fg & 7) : 30 + (newCell.fg & 7));
            break;
          case Attributes.CM_P256:
            switches.push(38);
            switches.push(5);
            switches.push(newCell.fg & 0xFF);
            break;
          case Attributes.CM_RGB:
            switches.push(38);
            switches.push(2);
            switches.push((newCell.fg >> 16) & 0xFF);
            switches.push((newCell.fg >> 8) & 0xFF);
            switches.push(newCell.fg & 0xFF);
            break;
          default:
            switches.push(39);
        }
      }
    }
    if (oldCell.bg !== newCell.bg) {
      // flags
      if ((oldCell.bg & BgFlags.ITALIC) !== (newCell.bg & BgFlags.ITALIC)) {
        switches.push(newCell.bg & BgFlags.ITALIC ? 3 : 23);
      }
      if ((oldCell.bg & BgFlags.DIM) !== (newCell.bg & BgFlags.DIM)) {
        switches.push(newCell.bg & BgFlags.DIM ? 2 : 22);
      }
      // colors
      if ((oldCell.bg & (Attributes.CM_MASK | Attributes.RGB_MASK)) !== (newCell.bg & (Attributes.CM_MASK | Attributes.RGB_MASK))) {
        switch (newCell.bg & Attributes.CM_MASK) {
          case Attributes.CM_P16:
            switches.push(newCell.bg & 8 ? 100 + (newCell.bg & 7) : 40 + (newCell.bg & 7));
            break;
          case Attributes.CM_P256:
            switches.push(48);
            switches.push(5);
            switches.push(newCell.bg & 0xFF);
            break;
          case Attributes.CM_RGB:
            switches.push(48);
            switches.push(2);
            switches.push((newCell.bg >> 16) & 0xFF);
            switches.push((newCell.bg >> 8) & 0xFF);
            switches.push(newCell.bg & 0xFF);
            break;
          default:
            switches.push(49);
        }
      }
    }
    return `\x1b[${switches.join(';')}m`;
  }

  public serialize(): string {
    if (!this._terminal) {
      return '';
    }

    // grab cell ctor from private
    const ctor = (this._terminal as any)._core._inputHandler._workCell.constructor;
    const cell1 = new ctor();
    const cell2 = new ctor();
    let oldCell = cell1;

    const result: string[] = [];

    // peek into circularlist and grab all lines for now
    const end = (this._terminal as any)._core.buffer.lines._length;
    for (let y = 0; y < end; ++y) {
      let sLine = '';
      const line = (this._terminal as any)._core.buffer.lines.get(y);
      const length = line.getTrimmedLength();
      for (let x = 0; x < length;) {
        const newCell = line.loadCell(x, oldCell === cell1 ? cell2 : cell1);
        if (oldCell.fg !== newCell.fg || oldCell.bg !== newCell.bg) {
          sLine += this._extractAttributes(oldCell, newCell);
          oldCell = newCell;
        }
        sLine += newCell.getChars();
        x += newCell.getWidth();
      }
      result.push(sLine);
    }
    return result.join('\r\n');
  }
}