Alternate buffer improvement

src/Buffer.ts

@@ -38,6 +38,7 @@ export class Buffer implements IBuffer {
   public tabs: any;
   public savedY: number;
   public savedX: number;
+  public savedCurAttr: number;
   public markers: Marker[] = [];
   private _bufferLineConstructor: IBufferLineConstructor;
 
@@ -113,11 +114,14 @@ export class Buffer implements IBuffer {
   /**
    * Fills the buffer's viewport with blank lines.
    */
-  public fillViewportRows(): void {
+  public fillViewportRows(fillAttr?: number): void {
     if (this.lines.length === 0) {
+      if (fillAttr === undefined) {
+        fillAttr = DEFAULT_ATTR;
+      }
       let i = this._terminal.rows;
       while (i--) {
-        this.lines.push(this.getBlankLine(DEFAULT_ATTR));
+        this.lines.push(this.getBlankLine(fillAttr));
       }
     }
   }

src/BufferSet.test.ts

@@ -48,4 +48,30 @@ describe('BufferSet', () => {
       assert.equal(bufferSet.active, bufferSet.alt);
     });
   });
+
+  describe('cursor handling when swapping buffers', () => {
+    beforeEach(() => {
+      bufferSet.normal.x = 0;
+      bufferSet.normal.y = 0;
+      bufferSet.alt.x = 0;
+      bufferSet.alt.y = 0;
+    });
+
+    it('should keep the cursor stationary when activating alt buffer', () => {
+      bufferSet.activateNormalBuffer();
+      bufferSet.active.x = 30;
+      bufferSet.active.y = 10;
+      bufferSet.activateAltBuffer();
+      assert.equal(bufferSet.active.x, 30);
+      assert.equal(bufferSet.active.y, 10);
+    });
+    it('should keep the cursor stationary when activating normal buffer', () => {
+      bufferSet.activateAltBuffer();
+      bufferSet.active.x = 30;
+      bufferSet.active.y = 10;
+      bufferSet.activateNormalBuffer();
+      assert.equal(bufferSet.active.x, 30);
+      assert.equal(bufferSet.active.y, 10);
+    });
+  });
 });

src/BufferSet.ts

@@ -61,6 +61,8 @@ export class BufferSet extends EventEmitter implements IBufferSet {
     if (this._activeBuffer === this._normal) {
       return;
     }
+    this._normal.x = this._alt.x;
+    this._normal.y = this._alt.y;
     // The alt buffer should always be cleared when we switch to the normal
     // buffer. This frees up memory since the alt buffer should always be new
     // when activated.
@@ -75,13 +77,15 @@ export class BufferSet extends EventEmitter implements IBufferSet {
   /**
    * Sets the alt Buffer of the BufferSet as its currently active Buffer
    */
-  public activateAltBuffer(): void {
+  public activateAltBuffer(fillAttr?: number): void {
     if (this._activeBuffer === this._alt) {
       return;
     }
     // Since the alt buffer is always cleared when the normal buffer is
     // activated, we want to fill it when switching to it.
-    this._alt.fillViewportRows();
+    this._alt.fillViewportRows(fillAttr);
+    this._alt.x = this._normal.x;
+    this._alt.y = this._normal.y;
     this._activeBuffer = this._alt;
     this.emit('activate', {
       activeBuffer: this._alt,

src/InputHandler.test.ts

@@ -6,7 +6,7 @@
 import { assert, expect } from 'chai';
 import { InputHandler } from './InputHandler';
 import { MockInputHandlingTerminal } from './utils/TestUtils.test';
-import { NULL_CELL_CHAR, NULL_CELL_CODE, NULL_CELL_WIDTH, CHAR_DATA_CHAR_INDEX } from './Buffer';
+import { NULL_CELL_CHAR, NULL_CELL_CODE, NULL_CELL_WIDTH, CHAR_DATA_CHAR_INDEX, CHAR_DATA_ATTR_INDEX, DEFAULT_ATTR } from './Buffer';
 import { Terminal } from './Terminal';
 import { IBufferLine } from './Types';
 
@@ -506,4 +506,65 @@ describe('InputHandler', () => {
       inputHandler.print(String.fromCharCode(0x200B), 0, 1);
     });
   });
+
+  describe('alt screen', () => {
+    let term: Terminal;
+    let handler: InputHandler;
+
+    function lineContent(line: IBufferLine): string {
+      let content = '';
+      for (let i = 0; i < line.length; ++i) content += line.get(i)[CHAR_DATA_CHAR_INDEX];
+      return content;
+    }
+
+    beforeEach(() => {
+      term = new Terminal();
+      handler = new InputHandler(term);
+    });
+    it('should handle DECSET/DECRST 47 (alt screen buffer)', () => {
+      handler.parse('\x1b[?47h\r\n\x1b[31mJUNK\x1b[?47lTEST');
+      expect(lineContent(term.buffer.lines.get(0))).to.equal(Array(term.cols + 1).join(' '));
+      expect(lineContent(term.buffer.lines.get(1))).to.equal('    TEST' + Array(term.cols - 7).join(' '));
+      // Text color of 'TEST' should be red
+      expect((term.buffer.lines.get(1).get(4)[CHAR_DATA_ATTR_INDEX] >> 9) & 0x1ff).to.equal(1);
+    });
+    it('should handle DECSET/DECRST 1047 (alt screen buffer)', () => {
+      handler.parse('\x1b[?1047h\r\n\x1b[31mJUNK\x1b[?1047lTEST');
+      expect(lineContent(term.buffer.lines.get(0))).to.equal(Array(term.cols + 1).join(' '));
+      expect(lineContent(term.buffer.lines.get(1))).to.equal('    TEST' + Array(term.cols - 7).join(' '));
+      // Text color of 'TEST' should be red
+      expect((term.buffer.lines.get(1).get(4)[CHAR_DATA_ATTR_INDEX] >> 9) & 0x1ff).to.equal(1);
+    });
+    it('should handle DECSET/DECRST 1048 (alt screen cursor)', () => {
+      handler.parse('\x1b[?1048h\r\n\x1b[31mJUNK\x1b[?1048lTEST');
+      expect(lineContent(term.buffer.lines.get(0))).to.equal('TEST' + Array(term.cols - 3).join(' '));
+      expect(lineContent(term.buffer.lines.get(1))).to.equal('JUNK' + Array(term.cols - 3).join(' '));
+      // Text color of 'TEST' should be default
+      expect(term.buffer.lines.get(0).get(0)[CHAR_DATA_ATTR_INDEX]).to.equal(DEFAULT_ATTR);
+      // Text color of 'JUNK' should be red
+      expect((term.buffer.lines.get(1).get(0)[CHAR_DATA_ATTR_INDEX] >> 9) & 0x1ff).to.equal(1);
+    });
+    it('should handle DECSET/DECRST 1049 (alt screen buffer+cursor)', () => {
+      handler.parse('\x1b[?1049h\r\n\x1b[31mJUNK\x1b[?1049lTEST');
+      expect(lineContent(term.buffer.lines.get(0))).to.equal('TEST' + Array(term.cols - 3).join(' '));
+      expect(lineContent(term.buffer.lines.get(1))).to.equal(Array(term.cols + 1).join(' '));
+      // Text color of 'TEST' should be default
+      expect(term.buffer.lines.get(0).get(0)[CHAR_DATA_ATTR_INDEX]).to.equal(DEFAULT_ATTR);
+    });
+    it('should handle DECSET/DECRST 1049 - maintains saved cursor for alt buffer', () => {
+      handler.parse('\x1b[?1049h\r\n\x1b[31m\x1b[s\x1b[?1049lTEST');
+      expect(lineContent(term.buffer.lines.get(0))).to.equal('TEST' + Array(term.cols - 3).join(' '));
+      // Text color of 'TEST' should be default
+      expect(term.buffer.lines.get(0).get(0)[CHAR_DATA_ATTR_INDEX]).to.equal(DEFAULT_ATTR);
+      handler.parse('\x1b[?1049h\x1b[uTEST');
+      expect(lineContent(term.buffer.lines.get(1))).to.equal('TEST' + Array(term.cols - 3).join(' '));
+      // Text color of 'TEST' should be red
+      expect((term.buffer.lines.get(1).get(0)[CHAR_DATA_ATTR_INDEX] >> 9) & 0x1ff).to.equal(1);
+    });
+    it('should handle DECSET/DECRST 1049 - clears alt buffer with erase attributes', () => {
+      handler.parse('\x1b[42m\x1b[?1049h');
+      // Buffer should be filled with green background
+      expect(term.buffer.lines.get(20).get(10)[CHAR_DATA_ATTR_INDEX] & 0x1ff).to.equal(2);
+    });
+  });
 });

src/InputHandler.ts

@@ -1284,7 +1284,9 @@ export class InputHandler extends Disposable implements IInputHandler {
         case 66:
           this._terminal.log('Serial port requested application keypad.');
           this._terminal.applicationKeypad = true;
-          this._terminal.viewport.syncScrollArea();
+          if (this._terminal.viewport) {
+            this._terminal.viewport.syncScrollArea();
+          }
           break;
         case 9: // X10 Mouse
           // no release, no motion, no wheel, no modifiers.
@@ -1333,14 +1335,19 @@ export class InputHandler extends Disposable implements IInputHandler {
         case 25: // show cursor
           this._terminal.cursorHidden = false;
           break;
+        case 1048: // alt screen cursor
+          this.saveCursor(params);
+          break;
         case 1049: // alt screen buffer cursor
-          // TODO: Not sure if we need to save/restore after switching the buffer
-          // this.saveCursor(params);
+          this.saveCursor(params);
           // FALL-THROUGH
         case 47: // alt screen buffer
         case 1047: // alt screen buffer
-          this._terminal.buffers.activateAltBuffer();
-          this._terminal.viewport.syncScrollArea();
+          this._terminal.buffers.activateAltBuffer(this._terminal.eraseAttr());
+          this._terminal.refresh(0, this._terminal.rows - 1);
+          if (this._terminal.viewport) {
+            this._terminal.viewport.syncScrollArea();
+          }
           this._terminal.showCursor();
           break;
         case 2004: // bracketed paste mode (https://cirw.in/blog/bracketed-paste)
@@ -1473,7 +1480,9 @@ export class InputHandler extends Disposable implements IInputHandler {
         case 66:
           this._terminal.log('Switching back to normal keypad.');
           this._terminal.applicationKeypad = false;
-          this._terminal.viewport.syncScrollArea();
+          if (this._terminal.viewport) {
+            this._terminal.viewport.syncScrollArea();
+          }
           break;
         case 9: // X10 Mouse
         case 1000: // vt200 mouse
@@ -1501,18 +1510,22 @@ export class InputHandler extends Disposable implements IInputHandler {
         case 25: // hide cursor
           this._terminal.cursorHidden = true;
           break;
+        case 1048: // alt screen cursor
+          this.restoreCursor(params);
+          break;
         case 1049: // alt screen buffer cursor
            // FALL-THROUGH
         case 47: // normal screen buffer
         case 1047: // normal screen buffer - clearing it first
           // Ensure the selection manager has the correct buffer
           this._terminal.buffers.activateNormalBuffer();
-          // TODO: Not sure if we need to save/restore after switching the buffer
-          // if (params[0] === 1049) {
-          //   this.restoreCursor(params);
-          // }
+          if (params[0] === 1049) {
+            this.restoreCursor(params);
+          }
           this._terminal.refresh(0, this._terminal.rows - 1);
-          this._terminal.viewport.syncScrollArea();
+          if (this._terminal.viewport) {
+            this._terminal.viewport.syncScrollArea();
+          }
           this._terminal.showCursor();
           break;
         case 2004: // bracketed paste mode (https://cirw.in/blog/bracketed-paste)
@@ -1791,7 +1804,9 @@ export class InputHandler extends Disposable implements IInputHandler {
       this._terminal.originMode = false;
       this._terminal.wraparoundMode = true;  // defaults: xterm - true, vt100 - false
       this._terminal.applicationKeypad = false; // ?
-      this._terminal.viewport.syncScrollArea();
+      if (this._terminal.viewport) {
+        this._terminal.viewport.syncScrollArea();
+      }
       this._terminal.applicationCursor = false;
       this._terminal.buffer.scrollTop = 0;
       this._terminal.buffer.scrollBottom = this._terminal.rows - 1;
@@ -1858,7 +1873,7 @@ export class InputHandler extends Disposable implements IInputHandler {
   public saveCursor(params: number[]): void {
     this._terminal.buffer.savedX = this._terminal.buffer.x;
     this._terminal.buffer.savedY = this._terminal.buffer.y;
-    this._terminal.savedCurAttr = this._terminal.curAttr;
+    this._terminal.buffer.savedCurAttr = this._terminal.curAttr;
   }
 
 
@@ -1870,7 +1885,7 @@ export class InputHandler extends Disposable implements IInputHandler {
   public restoreCursor(params: number[]): void {
     this._terminal.buffer.x = this._terminal.buffer.savedX || 0;
     this._terminal.buffer.y = this._terminal.buffer.savedY || 0;
-    this._terminal.curAttr = this._terminal.savedCurAttr || DEFAULT_ATTR;
+    this._terminal.curAttr = this._terminal.buffer.savedCurAttr || DEFAULT_ATTR;
   }
 
 

src/Terminal.ts

@@ -170,7 +170,6 @@ export class Terminal extends EventEmitter implements ITerminal, IDisposable, II
   public savedCols: number;
 
   public curAttr: number;
-  public savedCurAttr: number;
 
   public params: (string | number)[];
   public currentParam: string | number;

src/Types.ts

@@ -49,7 +49,6 @@ export interface IInputHandlingTerminal extends IEventEmitter {
   wraparoundMode: boolean;
   bracketedPasteMode: boolean;
   curAttr: number;
-  savedCurAttr: number;
   savedCols: number;
   x10Mouse: boolean;
   vt200Mouse: boolean;
@@ -290,6 +289,7 @@ export interface IBuffer {
   hasScrollback: boolean;
   savedY: number;
   savedX: number;
+  savedCurAttr: number;
   isCursorInViewport: boolean;
   translateBufferLineToString(lineIndex: number, trimRight: boolean, startCol?: number, endCol?: number): string;
   getWrappedRangeForLine(y: number): { first: number, last: number };
@@ -306,7 +306,7 @@ export interface IBufferSet extends IEventEmitter {
   active: IBuffer;
 
   activateNormalBuffer(): void;
-  activateAltBuffer(): void;
+  activateAltBuffer(fillAttr?: number): void;
 }
 
 export interface ISelectionManager {

src/utils/TestUtils.test.ts

@@ -182,7 +182,6 @@ export class MockInputHandlingTerminal implements IInputHandlingTerminal {
   wraparoundMode: boolean;
   bracketedPasteMode: boolean;
   curAttr: number;
-  savedCurAttr: number;
   savedCols: number;
   x10Mouse: boolean;
   vt200Mouse: boolean;
@@ -304,6 +303,7 @@ export class MockBuffer implements IBuffer {
   scrollTop: number;
   savedY: number;
   savedX: number;
+  savedCurAttr: number;
   translateBufferLineToString(lineIndex: number, trimRight: boolean, startCol?: number, endCol?: number): string {
     return Buffer.prototype.translateBufferLineToString.apply(this, arguments);
   }