add null and whitespace placeholder cells to buffer

src/Buffer.ts

@@ -4,10 +4,10 @@
  */
 
 import { CircularList } from './common/CircularList';
-import { CharData, ITerminal, IBuffer, IBufferLine, BufferIndex, IBufferStringIterator, IBufferStringIteratorResult } from './Types';
+import { CharData, ITerminal, IBuffer, IBufferLine, BufferIndex, IBufferStringIterator, IBufferStringIteratorResult, ICellData } from './Types';
 import { EventEmitter } from './common/EventEmitter';
 import { IMarker } from 'xterm';
-import { BufferLine } from './BufferLine';
+import { BufferLine, CellData } from './BufferLine';
 import { DEFAULT_COLOR } from './renderer/atlas/Types';
 
 export const DEFAULT_ATTR = (0 << 18) | (DEFAULT_COLOR << 9) | (256 << 0);
@@ -45,6 +45,8 @@ export class Buffer implements IBuffer {
   public savedX: number;
   public savedCurAttr: number;
   public markers: Marker[] = [];
+  private _nullCell: ICellData = CellData.fromCharData([0, NULL_CELL_CHAR, NULL_CELL_WIDTH, NULL_CELL_CODE]);
+  private _whitespaceCell: ICellData = CellData.fromCharData([0, WHITESPACE_CELL_CHAR, WHITESPACE_CELL_WIDTH, WHITESPACE_CELL_CODE]);
 
   /**
    * Create a new Buffer.
@@ -59,6 +61,18 @@ export class Buffer implements IBuffer {
     this.clear();
   }
 
+  public getNullCell(fg: number = 0, bg: number = 0): ICellData {
+    this._nullCell.fg = fg;
+    this._nullCell.bg = bg;
+    return this._nullCell;
+  }
+
+  public getWhitespaceCell(fg: number = 0, bg: number = 0): ICellData {
+    this._whitespaceCell.fg = fg;
+    this._whitespaceCell.bg = bg;
+    return this._whitespaceCell;
+  }
+
   public getBlankLine(attr: number, isWrapped?: boolean): IBufferLine {
     const fillCharData: CharData = [attr, NULL_CELL_CHAR, NULL_CELL_WIDTH, NULL_CELL_CODE];
     return new BufferLine(this._terminal.cols, fillCharData, isWrapped);

src/InputHandler.ts

@@ -519,13 +519,10 @@ export class InputHandler extends Disposable implements IInputHandler {
    * Insert Ps (Blank) Character(s) (default = 1) (ICH).
    */
   public insertChars(params: number[]): void {
-    this._cell.content = 0;
-    this._cell.fg = this._terminal.eraseAttr();
-    this._cell.bg = 0;
     this._terminal.buffer.lines.get(this._terminal.buffer.y + this._terminal.buffer.ybase).insertCells(
       this._terminal.buffer.x,
       params[0] || 1,
-      this._cell
+      this._terminal.buffer.getNullCell(this._terminal.eraseAttr())
     );
     this._terminal.updateRange(this._terminal.buffer.y);
   }

src/Types.ts

@@ -298,6 +298,8 @@ export interface IBuffer {
   getBlankLine(attr: number, isWrapped?: boolean): IBufferLine;
   stringIndexToBufferIndex(lineIndex: number, stringIndex: number): number[];
   iterator(trimRight: boolean, startIndex?: number, endIndex?: number, startOverscan?: number, endOverscan?: number): IBufferStringIterator;
+  getNullCell(fg?: number, bg?: number): ICellData;
+  getWhitespaceCell(fg?: number, bg?: number): ICellData;
 }
 
 export interface IBufferSet extends IEventEmitter {

src/ui/TestUtils.test.ts

@@ -4,7 +4,7 @@
  */
 
 import { IColorSet, IRenderer, IRenderDimensions, IColorManager } from '../renderer/Types';
-import { IInputHandlingTerminal, IViewport, ICompositionHelper, ITerminal, IBuffer, IBufferSet, IBrowser, ICharMeasure, ISelectionManager, ITerminalOptions, ILinkifier, IMouseHelper, ILinkMatcherOptions, CharacterJoinerHandler, IBufferLine, IBufferStringIterator } from '../Types';
+import { IInputHandlingTerminal, IViewport, ICompositionHelper, ITerminal, IBuffer, IBufferSet, IBrowser, ICharMeasure, ISelectionManager, ITerminalOptions, ILinkifier, IMouseHelper, ILinkMatcherOptions, CharacterJoinerHandler, IBufferLine, IBufferStringIterator, ICellData } from '../Types';
 import { ICircularList, XtermListener } from '../common/Types';
 import { Buffer } from '../Buffer';
 import * as Browser from '../core/Platform';
@@ -334,6 +334,12 @@ export class MockBuffer implements IBuffer {
   iterator(trimRight: boolean, startIndex?: number, endIndex?: number): IBufferStringIterator {
     return Buffer.prototype.iterator.apply(this, arguments);
   }
+  getNullCell(fg: number = 0, bg: number = 0): ICellData {
+    throw new Error('Method not implemented.');
+  }
+  getWhitespaceCell(fg: number = 0, bg: number = 0): ICellData {
+    throw new Error('Method not implemented.');
+  }
 }
 
 export class MockRenderer implements IRenderer {