change buffer interface from IBuffer to IBufferNamespace

addons/xterm-addon-attach/src/AttachAddon.api.ts

@@ -37,7 +37,7 @@ describe('AttachAddon', () => {
     const server = new WebSocket.Server({ port });
     server.on('connection', socket => socket.send('foo'));
     await page.evaluate(`window.term.loadAddon(new window.AttachAddon(new WebSocket('ws://localhost:${port}')))`);
-    await pollFor(page, `window.term.buffer.getLine(0).translateToString(true)`, 'foo');
+    await pollFor(page, `window.term.buffer.active.getLine(0).translateToString(true)`, 'foo');
     server.close();
   });
 
@@ -48,7 +48,7 @@ describe('AttachAddon', () => {
     const data = new Uint8Array([102, 111, 111]);
     server.on('connection', socket => socket.send(data));
     await page.evaluate(`window.term.loadAddon(new window.AttachAddon(new WebSocket('ws://localhost:${port}')))`);
-    await pollFor(page, `window.term.buffer.getLine(0).translateToString(true)`, 'foo');
+    await pollFor(page, `window.term.buffer.active.getLine(0).translateToString(true)`, 'foo');
     server.close();
   });
 });

addons/xterm-addon-search/src/SearchAddon.api.ts

@@ -61,7 +61,7 @@ describe('Search Tests', function(): void {
     await page.evaluate(`window.term.writeln('package.jsonc\\n')`);
     await writeSync(page, 'package.json pack package.lock');
     await page.evaluate(`window.search.findPrevious('pack', {incremental: true})`);
-    let line: string = await page.evaluate(`window.term.buffer.getLine(window.term.getSelectionPosition().startRow).translateToString()`);
+    let line: string = await page.evaluate(`window.term.buffer.active.getLine(window.term.getSelectionPosition().startRow).translateToString()`);
     let selectionPosition: { startColumn: number, startRow: number, endColumn: number, endRow: number } = await page.evaluate(`window.term.getSelectionPosition()`);
     // We look further ahead in the line to ensure that pack was selected from package.lock
     assert.deepEqual(line.substring(selectionPosition.startColumn, selectionPosition.endColumn + 8), 'package.lock');
@@ -70,7 +70,7 @@ describe('Search Tests', function(): void {
     assert.deepEqual(line.substring(selectionPosition.startColumn, selectionPosition.endColumn + 3), 'package.json');
     await page.evaluate(`window.search.findPrevious('package.jsonc', {incremental: true})`);
     // We have to reevaluate line because it should have switched starting rows at this point
-    line = await page.evaluate(`window.term.buffer.getLine(window.term.getSelectionPosition().startRow).translateToString()`);
+    line = await page.evaluate(`window.term.buffer.active.getLine(window.term.getSelectionPosition().startRow).translateToString()`);
     selectionPosition = await page.evaluate(`window.term.getSelectionPosition()`);
     assert.deepEqual(line.substring(selectionPosition.startColumn, selectionPosition.endColumn), 'package.jsonc');
   });
@@ -78,7 +78,7 @@ describe('Search Tests', function(): void {
     await page.evaluate(`window.term.writeln('package.lock pack package.json package.ups\\n')`);
     await writeSync(page, 'package.jsonc');
     await page.evaluate(`window.search.findNext('pack', {incremental: true})`);
-    let line: string = await page.evaluate(`window.term.buffer.getLine(window.term.getSelectionPosition().startRow).translateToString()`);
+    let line: string = await page.evaluate(`window.term.buffer.active.getLine(window.term.getSelectionPosition().startRow).translateToString()`);
     let selectionPosition: { startColumn: number, startRow: number, endColumn: number, endRow: number } = await page.evaluate(`window.term.getSelectionPosition()`);
     // We look further ahead in the line to ensure that pack was selected from package.lock
     assert.deepEqual(line.substring(selectionPosition.startColumn, selectionPosition.endColumn + 8), 'package.lock');
@@ -87,7 +87,7 @@ describe('Search Tests', function(): void {
     assert.deepEqual(line.substring(selectionPosition.startColumn, selectionPosition.endColumn + 3), 'package.json');
     await page.evaluate(`window.search.findNext('package.jsonc', {incremental: true})`);
     // We have to reevaluate line because it should have switched starting rows at this point
-    line = await page.evaluate(`window.term.buffer.getLine(window.term.getSelectionPosition().startRow).translateToString()`);
+    line = await page.evaluate(`window.term.buffer.active.getLine(window.term.getSelectionPosition().startRow).translateToString()`);
     selectionPosition = await page.evaluate(`window.term.getSelectionPosition()`);
     assert.deepEqual(line.substring(selectionPosition.startColumn, selectionPosition.endColumn), 'package.jsonc');
   });

addons/xterm-addon-search/src/SearchAddon.ts

@@ -87,7 +87,7 @@ export class SearchAddon implements ITerminalAddon {
     // Search from startRow + 1 to end
     if (!result) {
 
-      for (let y = startRow + 1; y < this._terminal.buffer.baseY + this._terminal.rows; y++) {
+      for (let y = startRow + 1; y < this._terminal.buffer.active.baseY + this._terminal.rows; y++) {
         searchPosition.startRow = y;
         searchPosition.startCol = 0;
         // If the current line is wrapped line, increase index of column to ignore the previous scan
@@ -135,7 +135,7 @@ export class SearchAddon implements ITerminalAddon {
     }
 
     const isReverseSearch = true;
-    let startRow = this._terminal.buffer.baseY + this._terminal.rows;
+    let startRow = this._terminal.buffer.active.baseY + this._terminal.rows;
     let startCol = this._terminal.cols;
     let result: ISearchResult | undefined;
     const incremental = searchOptions ? searchOptions.incremental : false;
@@ -174,8 +174,8 @@ export class SearchAddon implements ITerminalAddon {
       }
     }
     // If we hit the top and didn't search from the very bottom wrap back down
-    if (!result && startRow !== (this._terminal.buffer.baseY + this._terminal.rows)) {
-      for (let y = (this._terminal.buffer.baseY + this._terminal.rows); y > startRow; y--) {
+    if (!result && startRow !== (this._terminal.buffer.active.baseY + this._terminal.rows)) {
+      for (let y = (this._terminal.buffer.active.baseY + this._terminal.rows); y > startRow; y--) {
         searchPosition.startRow = y;
         result = this._findInLine(term, searchPosition, searchOptions, isReverseSearch);
         if (result) {
@@ -197,7 +197,7 @@ export class SearchAddon implements ITerminalAddon {
   private _initLinesCache(): void {
     const terminal = this._terminal!;
     if (!this._linesCache) {
-      this._linesCache = new Array(terminal.buffer.length);
+      this._linesCache = new Array(terminal.buffer.active.length);
       this._cursorMoveListener = terminal.onCursorMove(() => this._destroyLinesCache());
       this._resizeListener = terminal.onResize(() => this._destroyLinesCache());
     }
@@ -249,7 +249,7 @@ export class SearchAddon implements ITerminalAddon {
     const col = searchPosition.startCol;
 
     // Ignore wrapped lines, only consider on unwrapped line (first row of command string).
-    const firstLine = terminal.buffer.getLine(row);
+    const firstLine = terminal.buffer.active.getLine(row);
     if (firstLine && firstLine.isWrapped) {
       if (isReverseSearch) {
         searchPosition.startCol += terminal.cols;
@@ -311,7 +311,7 @@ export class SearchAddon implements ITerminalAddon {
         return;
       }
 
-      const line = terminal.buffer.getLine(row);
+      const line = terminal.buffer.active.getLine(row);
 
       if (line) {
         for (let i = 0; i < resultIndex; i++) {
@@ -354,9 +354,9 @@ export class SearchAddon implements ITerminalAddon {
     let lineWrapsToNext: boolean;
 
     do {
-      const nextLine = terminal.buffer.getLine(lineIndex + 1);
+      const nextLine = terminal.buffer.active.getLine(lineIndex + 1);
       lineWrapsToNext = nextLine ? nextLine.isWrapped : false;
-      const line = terminal.buffer.getLine(lineIndex);
+      const line = terminal.buffer.active.getLine(lineIndex);
       if (!line) {
         break;
       }
@@ -380,8 +380,8 @@ export class SearchAddon implements ITerminalAddon {
     }
     terminal.select(result.col, result.row, result.term.length);
     // If it is not in the viewport then we scroll else it just gets selected
-    if (result.row >= (terminal.buffer.viewportY + terminal.rows) || result.row < terminal.buffer.viewportY) {
-      let scroll = result.row - terminal.buffer.viewportY;
+    if (result.row >= (terminal.buffer.active.viewportY + terminal.rows) || result.row < terminal.buffer.active.viewportY) {
+      let scroll = result.row - terminal.buffer.active.viewportY;
       scroll = scroll - Math.floor(terminal.rows / 2);
       terminal.scrollLines(scroll);
     }

addons/xterm-addon-serialize/src/SerializeAddon.ts

@@ -175,8 +175,8 @@ export class SerializeAddon implements ITerminalAddon {
       throw new Error('Cannot use addon until it has been loaded');
     }
 
-    const maxRows = this._terminal.buffer.length;
-    const handler = new StringSerializeHandler(this._terminal.buffer);
+    const maxRows = this._terminal.buffer.active.length;
+    const handler = new StringSerializeHandler(this._terminal.buffer.active);
 
     rows = (rows === undefined) ? maxRows : constrain(rows, 0, maxRows);
 

addons/xterm-addon-web-links/src/WebLinkProvider.ts

@@ -84,7 +84,7 @@ export class LinkComputer {
     let prevLinesToWrap: boolean;
 
     do {
-      const line = terminal.buffer.getLine(lineIndex);
+      const line = terminal.buffer.active.getLine(lineIndex);
       if (!line) {
         break;
       }
@@ -99,9 +99,9 @@ export class LinkComputer {
     const startLineIndex = lineIndex;
 
     do {
-      const nextLine = terminal.buffer.getLine(lineIndex + 1);
+      const nextLine = terminal.buffer.active.getLine(lineIndex + 1);
       lineWrapsToNext = nextLine ? nextLine.isWrapped : false;
-      const line = terminal.buffer.getLine(lineIndex);
+      const line = terminal.buffer.active.getLine(lineIndex);
       if (!line) {
         break;
       }

addons/xterm-addon-webgl/src/GlyphRenderer.ts

@@ -250,7 +250,7 @@ export class GlyphRenderer {
 
   private _updateSelectionRange(startCol: number, endCol: number, y: number, model: IRenderModel, bg: number): void {
     const terminal = this._terminal;
-    const row = y + terminal.buffer.viewportY;
+    const row = y + terminal.buffer.active.viewportY;
     let line: IBufferLine | undefined;
     for (let x = startCol; x < endCol; x++) {
       const offset = (y * this._terminal.cols + x) * RENDER_MODEL_INDICIES_PER_CELL;
@@ -281,7 +281,7 @@ export class GlyphRenderer {
       }
       if (code & COMBINED_CHAR_BIT_MASK) {
         if (!line) {
-          line = terminal.buffer.getLine(row);
+          line = terminal.buffer.active.getLine(row);
         }
         const chars = line!.getCell(x)!.getChars();
         this._updateCell(this._vertices.selectionAttributes, x, y, model.cells[offset], bg, fg, chars);

addons/xterm-addon-webgl/src/WebglRenderer.ts

@@ -302,8 +302,8 @@ export class WebglRenderer extends Disposable implements IRenderer {
     }
 
     // Translate from buffer position to viewport position
-    const viewportStartRow = start[1] - terminal.buffer.viewportY;
-    const viewportEndRow = end[1] - terminal.buffer.viewportY;
+    const viewportStartRow = start[1] - terminal.buffer.active.viewportY;
+    const viewportEndRow = end[1] - terminal.buffer.active.viewportY;
     const viewportCappedStartRow = Math.max(viewportStartRow, 0);
     const viewportCappedEndRow = Math.min(viewportEndRow, terminal.rows - 1);
 

addons/xterm-addon-webgl/src/renderLayer/CursorRenderLayer.ts

@@ -76,14 +76,14 @@ export class CursorRenderLayer extends BaseRenderLayer {
     if (this._cursorBlinkStateManager) {
       this._cursorBlinkStateManager.pause();
     }
-    this._onRequestRefreshRowsEvent.fire({ start: terminal.buffer.cursorY, end: terminal.buffer.cursorY });
+    this._onRequestRefreshRowsEvent.fire({ start: terminal.buffer.active.cursorY, end: terminal.buffer.active.cursorY });
   }
 
   public onFocus(terminal: Terminal): void {
     if (this._cursorBlinkStateManager) {
       this._cursorBlinkStateManager.resume(terminal);
     } else {
-      this._onRequestRefreshRowsEvent.fire({ start: terminal.buffer.cursorY, end: terminal.buffer.cursorY });
+      this._onRequestRefreshRowsEvent.fire({ start: terminal.buffer.active.cursorY, end: terminal.buffer.active.cursorY });
     }
   }
 
@@ -100,7 +100,7 @@ export class CursorRenderLayer extends BaseRenderLayer {
     }
     // Request a refresh from the terminal as management of rendering is being
     // moved back to the terminal
-    this._onRequestRefreshRowsEvent.fire({ start: terminal.buffer.cursorY, end: terminal.buffer.cursorY });
+    this._onRequestRefreshRowsEvent.fire({ start: terminal.buffer.active.cursorY, end: terminal.buffer.active.cursorY });
   }
 
   public onCursorMove(terminal: Terminal): void {
@@ -125,11 +125,11 @@ export class CursorRenderLayer extends BaseRenderLayer {
       return;
     }
 
-    const cursorY = terminal.buffer.baseY + terminal.buffer.cursorY;
-    const viewportRelativeCursorY = cursorY - terminal.buffer.viewportY;
+    const cursorY = terminal.buffer.active.baseY + terminal.buffer.active.cursorY;
+    const viewportRelativeCursorY = cursorY - terminal.buffer.active.viewportY;
 
     // in case cursor.x == cols adjust visual cursor to cols - 1
-    const cursorX = Math.min(terminal.buffer.cursorX, terminal.cols - 1);
+    const cursorX = Math.min(terminal.buffer.active.cursorX, terminal.cols - 1);
 
     // Don't draw the cursor if it's off-screen
     if (viewportRelativeCursorY < 0 || viewportRelativeCursorY >= terminal.rows) {

src/public/Terminal.ts

@@ -3,7 +3,7 @@
  * @license MIT
  */
 
-import { Terminal as ITerminalApi, ITerminalOptions, IMarker, IDisposable, ILinkMatcherOptions, ITheme, ILocalizableStrings, ITerminalAddon, ISelectionPosition, IBuffer as IBufferApi, IBufferSet as IBufferSetApi, IBufferLine as IBufferLineApi, IBufferCell as IBufferCellApi, IParser, IFunctionIdentifier, ILinkProvider, IUnicodeHandling, IUnicodeVersionProvider } from 'xterm';
+import { Terminal as ITerminalApi, ITerminalOptions, IMarker, IDisposable, ILinkMatcherOptions, ITheme, ILocalizableStrings, ITerminalAddon, ISelectionPosition, IBuffer as IBufferApi, IBufferNamespace as IBufferNamespaceApi, IBufferLine as IBufferLineApi, IBufferCell as IBufferCellApi, IParser, IFunctionIdentifier, ILinkProvider, IUnicodeHandling, IUnicodeVersionProvider } from 'xterm';
 import { ITerminal } from '../Types';
 import { IBufferLine, ICellData } from 'common/Types';
 import { IBuffer, IBufferSet } from 'common/buffer/Types';
@@ -48,8 +48,7 @@ export class Terminal implements ITerminalApi {
   public get textarea(): HTMLTextAreaElement | undefined { return this._core.textarea; }
   public get rows(): number { return this._core.rows; }
   public get cols(): number { return this._core.cols; }
-  public get buffer(): IBufferApi { return new BufferApiView(this._core.buffer); }
-  public get buffers(): IBufferSetApi { return new BufferSetApiView(this._core.buffers); }
+  public get buffer(): IBufferNamespaceApi { return new BufferNamespaceApi(this._core.buffers); }
   public get markers(): ReadonlyArray<IMarker> { return this._core.markers; }
   public blur(): void {
     this._core.blur();
@@ -194,8 +193,13 @@ export class Terminal implements ITerminalApi {
 }
 
 class BufferApiView implements IBufferApi {
-  constructor(private _buffer: IBuffer) { }
+  constructor(private _buffer: IBuffer, private _buffers: IBufferSet) { }
 
+  public get type(): 'normal' | 'alternate' {
+    if (this._buffers.normal === this._buffer) { return 'normal'; }
+    else if (this._buffers.alt === this._buffer) { return 'alternate'; }
+    throw new Error('Unknown buffer type');
+  }
   public get cursorY(): number { return this._buffer.y; }
   public get cursorX(): number { return this._buffer.x; }
   public get viewportY(): number { return this._buffer.ydisp; }
@@ -211,20 +215,17 @@ class BufferApiView implements IBufferApi {
   public getNullCell(): IBufferCellApi { return new CellData(); }
 }
 
-class BufferSetApiView implements IBufferSetApi {
+class BufferNamespaceApi implements IBufferNamespaceApi {
   constructor(private _buffers: IBufferSet) { }
 
-  public get alt(): IBufferApi { return new BufferApiView(this._buffers.alt); }
-  public get active(): IBufferApi { return new BufferApiView(this._buffers.active); }
-  public get normal(): IBufferApi { return new BufferApiView(this._buffers.normal); }
+  public get alternate(): IBufferApi { return new BufferApiView(this._buffers.alt, this._buffers); }
+  public get active(): IBufferApi { return new BufferApiView(this._buffers.active, this._buffers); }
+  public get normal(): IBufferApi { return new BufferApiView(this._buffers.normal, this._buffers); }
 
-  public get onBufferActivate(): IEvent<{ activeBuffer: IBufferApi, inactiveBuffer: IBufferApi }> {
-    return (listener: (arg1: { activeBuffer: IBufferApi, inactiveBuffer: IBufferApi }, arg2: void) => any) => {
-      return this._buffers.onBufferActivate((innerArg: { activeBuffer: IBuffer, inactiveBuffer: IBuffer }) => {
-        listener({
-          activeBuffer: new BufferApiView(innerArg.activeBuffer),
-          inactiveBuffer: new BufferApiView(innerArg.inactiveBuffer)
-        });
+  public get onBufferChange(): IEvent<IBufferApi> {
+    return (listener: (buffer: IBufferApi, unused: void) => any): IDisposable => {
+      return this._buffers.onBufferActivate((arg1: { activeBuffer: IBuffer, inactiveBuffer: IBuffer }) => {
+        listener(new BufferApiView(arg1.activeBuffer, this._buffers));
       });
     };
   }

test/api/CharWidth.api.ts

@@ -79,7 +79,7 @@ async function sumWidths(start: number, end: number, sentinel: string): Promise<
   await page.evaluate(`
     (function() {
       window.result = 0;
-      const buffer = window.term.buffer;
+      const buffer = window.term.buffer.active;
       for (let i = ${start}; i < ${end}; i++) {
         const line = buffer.getLine(i);
         let j = 0;

test/api/InputHandler.api.ts

@@ -165,7 +165,7 @@ describe('InputHandler Integration Tests', function(): void {
         window.term.reset()
         window.term.write('1\\n2\\n3\\n4\\n5${fixture}\x1b[3J')
       `);
-      await pollFor(page, () => page.evaluate(`window.term.buffer.length`), 5);
+      await pollFor(page, () => page.evaluate(`window.term.buffer.active.length`), 5);
       await pollFor(page, () => getLinesAsArray(5), ['   4', '    5', 'abc', 'def', 'ghi']);
     });
 
@@ -194,7 +194,7 @@ describe('InputHandler Integration Tests', function(): void {
         window.term.reset()
         window.term.write('1\\n2\\n3\\n4\\n5${fixture}\x1b[?3J')
       `);
-      await pollFor(page, () => page.evaluate(`window.term.buffer.length`), 5);
+      await pollFor(page, () => page.evaluate(`window.term.buffer.active.length`), 5);
       await pollFor(page, () => getLinesAsArray(5), ['   4', '    5', 'abc', 'def', 'ghi']);
     });
 
@@ -240,7 +240,7 @@ describe('InputHandler Integration Tests', function(): void {
       it('Report Cursor Position (CPR) - CSI 6 n', async function(): Promise<any> {
         await page.evaluate(`window.term.write('\\n\\nfoo')`);
         await pollFor(page, () => page.evaluate(`
-          [window.term.buffer.cursorY, window.term.buffer.cursorX]
+          [window.term.buffer.active.cursorY, window.term.buffer.active.cursorX]
         `), [2, 3]);
         await page.evaluate(`
           window.term.onData(e => window.result = e);
@@ -252,7 +252,7 @@ describe('InputHandler Integration Tests', function(): void {
       it('Report Cursor Position (DECXCPR) - CSI ? 6 n', async function(): Promise<any> {
         await page.evaluate(`window.term.write('\\n\\nfoo')`);
         await pollFor(page, () => page.evaluate(`
-          [window.term.buffer.cursorY, window.term.buffer.cursorX]
+          [window.term.buffer.active.cursorY, window.term.buffer.active.cursorX]
         `), [2, 3]);
         await page.evaluate(`
           window.term.onData(e => window.result = e);
@@ -410,7 +410,7 @@ describe('InputHandler Integration Tests', function(): void {
 async function getLinesAsArray(count: number, start: number = 0): Promise<string[]> {
   let text = '';
   for (let i = start; i < start + count; i++) {
-    text += `window.term.buffer.getLine(${i}).translateToString(true), `;
+    text += `window.term.buffer.active.getLine(${i}).translateToString(true),`;
   }
   return await page.evaluate(`[${text}]`);
 }
@@ -430,10 +430,10 @@ async function simulatePaste(text: string): Promise<string> {
 
 async function getCursor(): Promise<{ col: number, row: number }> {
   return page.evaluate(`
-            (function() {
-              return { col: term.buffer.cursorX, row: term.buffer.cursorY };
-            })();
-          `);
+  (function() {
+    return {col: term.buffer.active.cursorX, row: term.buffer.active.cursorY};
+  })();
+  `);
 }
 
 async function getDimensions(): Promise<any> {

test/api/Terminal.api.ts

@@ -41,7 +41,7 @@ describe('API Integration Tests', function(): void {
       window.term.write('bar');
       window.term.write('文');
     `);
-    await pollFor(page, `window.term.buffer.getLine(0).translateToString(true)`, 'foobar文');
+    await pollFor(page, `window.term.buffer.active.getLine(0).translateToString(true)`, 'foobar文');
   });
 
   it('write with callback', async () => {
@@ -51,7 +51,7 @@ describe('API Integration Tests', function(): void {
       window.term.write('bar', () => { window.__x += 'b'; });
       window.term.write('文', () => { window.__x += 'c'; });
     `);
-    await pollFor(page, `window.term.buffer.getLine(0).translateToString(true)`, 'foobar文');
+    await pollFor(page, `window.term.buffer.active.getLine(0).translateToString(true)`, 'foobar文');
     await pollFor(page, `window.__x`, 'abc');
   });
 
@@ -65,7 +65,7 @@ describe('API Integration Tests', function(): void {
       // 文
       window.term.write(new Uint8Array([230, 150, 135]));
     `);
-    await pollFor(page, `window.term.buffer.getLine(0).translateToString(true)`, 'foobar文');
+    await pollFor(page, `window.term.buffer.active.getLine(0).translateToString(true)`, 'foobar文');
   });
 
   it('write - bytes (UTF8) with callback', async () => {
@@ -78,7 +78,7 @@ describe('API Integration Tests', function(): void {
       // 文
       window.term.write(new Uint8Array([230, 150, 135]), () => { window.__x += 'C'; });
     `);
-    await pollFor(page, `window.term.buffer.getLine(0).translateToString(true)`, 'foobar文');
+    await pollFor(page, `window.term.buffer.active.getLine(0).translateToString(true)`, 'foobar文');
     await pollFor(page, `window.__x`, 'ABC');
   });
 
@@ -89,9 +89,9 @@ describe('API Integration Tests', function(): void {
       window.term.writeln('bar');
       window.term.writeln('文');
     `);
-    await pollFor(page, `window.term.buffer.getLine(0).translateToString(true)`, 'foo');
-    await pollFor(page, `window.term.buffer.getLine(1).translateToString(true)`, 'bar');
-    await pollFor(page, `window.term.buffer.getLine(2).translateToString(true)`, '文');
+    await pollFor(page, `window.term.buffer.active.getLine(0).translateToString(true)`, 'foo');
+    await pollFor(page, `window.term.buffer.active.getLine(1).translateToString(true)`, 'bar');
+    await pollFor(page, `window.term.buffer.active.getLine(2).translateToString(true)`, '文');
   });
 
   it('writeln with callback', async () => {
@@ -101,9 +101,9 @@ describe('API Integration Tests', function(): void {
       window.term.writeln('bar', () => { window.__x += '2'; });
       window.term.writeln('文', () => { window.__x += '3'; });
     `);
-    await pollFor(page, `window.term.buffer.getLine(0).translateToString(true)`, 'foo');
-    await pollFor(page, `window.term.buffer.getLine(1).translateToString(true)`, 'bar');
-    await pollFor(page, `window.term.buffer.getLine(2).translateToString(true)`, '文');
+    await pollFor(page, `window.term.buffer.active.getLine(0).translateToString(true)`, 'foo');
+    await pollFor(page, `window.term.buffer.active.getLine(1).translateToString(true)`, 'bar');
+    await pollFor(page, `window.term.buffer.active.getLine(2).translateToString(true)`, '文');
     await pollFor(page, `window.__x`, '123');
   });
 
@@ -114,9 +114,9 @@ describe('API Integration Tests', function(): void {
       window.term.writeln(new Uint8Array([98, 97, 114]));
       window.term.writeln(new Uint8Array([230, 150, 135]));
     `);
-    await pollFor(page, `window.term.buffer.getLine(0).translateToString(true)`, 'foo');
-    await pollFor(page, `window.term.buffer.getLine(1).translateToString(true)`, 'bar');
-    await pollFor(page, `window.term.buffer.getLine(2).translateToString(true)`, '文');
+    await pollFor(page, `window.term.buffer.active.getLine(0).translateToString(true)`, 'foo');
+    await pollFor(page, `window.term.buffer.active.getLine(1).translateToString(true)`, 'bar');
+    await pollFor(page, `window.term.buffer.active.getLine(2).translateToString(true)`, '文');
   });
 
   it('paste', async () => {
@@ -144,10 +144,10 @@ describe('API Integration Tests', function(): void {
     `);
     await pollFor(page, `window.parsed`, 9);
     await page.evaluate(`window.term.clear()`);
-    await pollFor(page, `window.term.buffer.length`, 5);
-    await pollFor(page, `window.term.buffer.getLine(0).translateToString(true)`, 'test9');
+    await pollFor(page, `window.term.buffer.active.length`, 5);
+    await pollFor(page, `window.term.buffer.active.getLine(0).translateToString(true)`, 'test9');
     for (let i = 1; i < 5; i++) {
-      await pollFor(page, `window.term.buffer.getLine(${i}).translateToString(true)`, '');
+      await pollFor(page, `window.term.buffer.active.getLine(${i}).translateToString(true)`, '');
     }
   });
 
@@ -400,113 +400,113 @@ describe('API Integration Tests', function(): void {
   describe('buffer', () => {
     it('cursorX, cursorY', async () => {
       await openTerminal(page, { rows: 5, cols: 5 });
-      assert.equal(await page.evaluate(`window.term.buffer.cursorX`), 0);
-      assert.equal(await page.evaluate(`window.term.buffer.cursorY`), 0);
+      assert.equal(await page.evaluate(`window.term.buffer.active.cursorX`), 0);
+      assert.equal(await page.evaluate(`window.term.buffer.active.cursorY`), 0);
       await writeSync(page, 'foo');
-      assert.equal(await page.evaluate(`window.term.buffer.cursorX`), 3);
-      assert.equal(await page.evaluate(`window.term.buffer.cursorY`), 0);
+      assert.equal(await page.evaluate(`window.term.buffer.active.cursorX`), 3);
+      assert.equal(await page.evaluate(`window.term.buffer.active.cursorY`), 0);
       await writeSync(page, '\\n');
-      assert.equal(await page.evaluate(`window.term.buffer.cursorX`), 3);
-      assert.equal(await page.evaluate(`window.term.buffer.cursorY`), 1);
+      assert.equal(await page.evaluate(`window.term.buffer.active.cursorX`), 3);
+      assert.equal(await page.evaluate(`window.term.buffer.active.cursorY`), 1);
       await writeSync(page, '\\r');
-      assert.equal(await page.evaluate(`window.term.buffer.cursorX`), 0);
-      assert.equal(await page.evaluate(`window.term.buffer.cursorY`), 1);
+      assert.equal(await page.evaluate(`window.term.buffer.active.cursorX`), 0);
+      assert.equal(await page.evaluate(`window.term.buffer.active.cursorY`), 1);
       await writeSync(page, 'abcde');
-      assert.equal(await page.evaluate(`window.term.buffer.cursorX`), 5);
-      assert.equal(await page.evaluate(`window.term.buffer.cursorY`), 1);
+      assert.equal(await page.evaluate(`window.term.buffer.active.cursorX`), 5);
+      assert.equal(await page.evaluate(`window.term.buffer.active.cursorY`), 1);
       await writeSync(page, '\\n\\r\\n\\n\\n\\n\\n');
-      assert.equal(await page.evaluate(`window.term.buffer.cursorX`), 0);
-      assert.equal(await page.evaluate(`window.term.buffer.cursorY`), 4);
+      assert.equal(await page.evaluate(`window.term.buffer.active.cursorX`), 0);
+      assert.equal(await page.evaluate(`window.term.buffer.active.cursorY`), 4);
     });
 
     it('viewportY', async () => {
       await openTerminal(page, { rows: 5 });
-      assert.equal(await page.evaluate(`window.term.buffer.viewportY`), 0);
+      assert.equal(await page.evaluate(`window.term.buffer.active.viewportY`), 0);
       await writeSync(page, '\\n\\n\\n\\n');
-      assert.equal(await page.evaluate(`window.term.buffer.viewportY`), 0);
+      assert.equal(await page.evaluate(`window.term.buffer.active.viewportY`), 0);
       await writeSync(page, '\\n');
-      assert.equal(await page.evaluate(`window.term.buffer.viewportY`), 1);
+      assert.equal(await page.evaluate(`window.term.buffer.active.viewportY`), 1);
       await writeSync(page, '\\n\\n\\n\\n');
-      assert.equal(await page.evaluate(`window.term.buffer.viewportY`), 5);
+      assert.equal(await page.evaluate(`window.term.buffer.active.viewportY`), 5);
       await page.evaluate(`window.term.scrollLines(-1)`);
-      assert.equal(await page.evaluate(`window.term.buffer.viewportY`), 4);
+      assert.equal(await page.evaluate(`window.term.buffer.active.viewportY`), 4);
       await page.evaluate(`window.term.scrollToTop()`);
-      assert.equal(await page.evaluate(`window.term.buffer.viewportY`), 0);
+      assert.equal(await page.evaluate(`window.term.buffer.active.viewportY`), 0);
     });
 
     it('baseY', async () => {
       await openTerminal(page, { rows: 5 });
-      assert.equal(await page.evaluate(`window.term.buffer.baseY`), 0);
+      assert.equal(await page.evaluate(`window.term.buffer.active.baseY`), 0);
       await writeSync(page, '\\n\\n\\n\\n');
-      assert.equal(await page.evaluate(`window.term.buffer.baseY`), 0);
+      assert.equal(await page.evaluate(`window.term.buffer.active.baseY`), 0);
       await writeSync(page, '\\n');
-      assert.equal(await page.evaluate(`window.term.buffer.baseY`), 1);
+      assert.equal(await page.evaluate(`window.term.buffer.active.baseY`), 1);
       await writeSync(page, '\\n\\n\\n\\n');
-      assert.equal(await page.evaluate(`window.term.buffer.baseY`), 5);
+      assert.equal(await page.evaluate(`window.term.buffer.active.baseY`), 5);
       await page.evaluate(`window.term.scrollLines(-1)`);
-      assert.equal(await page.evaluate(`window.term.buffer.baseY`), 5);
+      assert.equal(await page.evaluate(`window.term.buffer.active.baseY`), 5);
       await page.evaluate(`window.term.scrollToTop()`);
-      assert.equal(await page.evaluate(`window.term.buffer.baseY`), 5);
+      assert.equal(await page.evaluate(`window.term.buffer.active.baseY`), 5);
     });
 
     it('length', async () => {
       await openTerminal(page, { rows: 5 });
-      assert.equal(await page.evaluate(`window.term.buffer.length`), 5);
+      assert.equal(await page.evaluate(`window.term.buffer.active.length`), 5);
       await writeSync(page, '\\n\\n\\n\\n');
-      assert.equal(await page.evaluate(`window.term.buffer.length`), 5);
+      assert.equal(await page.evaluate(`window.term.buffer.active.length`), 5);
       await writeSync(page, '\\n');
-      assert.equal(await page.evaluate(`window.term.buffer.length`), 6);
+      assert.equal(await page.evaluate(`window.term.buffer.active.length`), 6);
       await writeSync(page, '\\n\\n\\n\\n');
-      assert.equal(await page.evaluate(`window.term.buffer.length`), 10);
+      assert.equal(await page.evaluate(`window.term.buffer.active.length`), 10);
     });
 
     describe('getLine', () => {
       it('invalid index', async () => {
         await openTerminal(page, { rows: 5 });
-        assert.equal(await page.evaluate(`window.term.buffer.getLine(-1)`), undefined);
-        assert.equal(await page.evaluate(`window.term.buffer.getLine(5)`), undefined);
+        assert.equal(await page.evaluate(`window.term.buffer.active.getLine(-1)`), undefined);
+        assert.equal(await page.evaluate(`window.term.buffer.active.getLine(5)`), undefined);
       });
 
       it('isWrapped', async () => {
         await openTerminal(page, { cols: 5 });
-        assert.equal(await page.evaluate(`window.term.buffer.getLine(0).isWrapped`), false);
-        assert.equal(await page.evaluate(`window.term.buffer.getLine(1).isWrapped`), false);
+        assert.equal(await page.evaluate(`window.term.buffer.active.getLine(0).isWrapped`), false);
+        assert.equal(await page.evaluate(`window.term.buffer.active.getLine(1).isWrapped`), false);
         await writeSync(page, 'abcde');
-        assert.equal(await page.evaluate(`window.term.buffer.getLine(0).isWrapped`), false);
-        assert.equal(await page.evaluate(`window.term.buffer.getLine(1).isWrapped`), false);
+        assert.equal(await page.evaluate(`window.term.buffer.active.getLine(0).isWrapped`), false);
+        assert.equal(await page.evaluate(`window.term.buffer.active.getLine(1).isWrapped`), false);
         await writeSync(page, 'f');
-        assert.equal(await page.evaluate(`window.term.buffer.getLine(0).isWrapped`), false);
-        assert.equal(await page.evaluate(`window.term.buffer.getLine(1).isWrapped`), true);
+        assert.equal(await page.evaluate(`window.term.buffer.active.getLine(0).isWrapped`), false);
+        assert.equal(await page.evaluate(`window.term.buffer.active.getLine(1).isWrapped`), true);
       });
 
       it('translateToString', async () => {
         await openTerminal(page, { cols: 5 });
-        assert.equal(await page.evaluate(`window.term.buffer.getLine(0).translateToString()`), '     ');
-        assert.equal(await page.evaluate(`window.term.buffer.getLine(0).translateToString(true)`), '');
+        assert.equal(await page.evaluate(`window.term.buffer.active.getLine(0).translateToString()`), '     ');
+        assert.equal(await page.evaluate(`window.term.buffer.active.getLine(0).translateToString(true)`), '');
         await writeSync(page, 'foo');
-        assert.equal(await page.evaluate(`window.term.buffer.getLine(0).translateToString()`), 'foo  ');
-        assert.equal(await page.evaluate(`window.term.buffer.getLine(0).translateToString(true)`), 'foo');
+        assert.equal(await page.evaluate(`window.term.buffer.active.getLine(0).translateToString()`), 'foo  ');
+        assert.equal(await page.evaluate(`window.term.buffer.active.getLine(0).translateToString(true)`), 'foo');
         await writeSync(page, 'bar');
-        assert.equal(await page.evaluate(`window.term.buffer.getLine(0).translateToString()`), 'fooba');
-        assert.equal(await page.evaluate(`window.term.buffer.getLine(0).translateToString(true)`), 'fooba');
-        assert.equal(await page.evaluate(`window.term.buffer.getLine(1).translateToString(true)`), 'r');
-        assert.equal(await page.evaluate(`window.term.buffer.getLine(0).translateToString(false, 1)`), 'ooba');
-        assert.equal(await page.evaluate(`window.term.buffer.getLine(0).translateToString(false, 1, 3)`), 'oo');
+        assert.equal(await page.evaluate(`window.term.buffer.active.getLine(0).translateToString()`), 'fooba');
+        assert.equal(await page.evaluate(`window.term.buffer.active.getLine(0).translateToString(true)`), 'fooba');
+        assert.equal(await page.evaluate(`window.term.buffer.active.getLine(1).translateToString(true)`), 'r');
+        assert.equal(await page.evaluate(`window.term.buffer.active.getLine(0).translateToString(false, 1)`), 'ooba');
+        assert.equal(await page.evaluate(`window.term.buffer.active.getLine(0).translateToString(false, 1, 3)`), 'oo');
       });
 
       it('getCell', async () => {
         await openTerminal(page, { cols: 5 });
-        assert.equal(await page.evaluate(`window.term.buffer.getLine(0).getCell(-1)`), undefined);
-        assert.equal(await page.evaluate(`window.term.buffer.getLine(0).getCell(5)`), undefined);
-        assert.equal(await page.evaluate(`window.term.buffer.getLine(0).getCell(0).getChars()`), '');
-        assert.equal(await page.evaluate(`window.term.buffer.getLine(0).getCell(0).getWidth()`), 1);
+        assert.equal(await page.evaluate(`window.term.buffer.active.getLine(0).getCell(-1)`), undefined);
+        assert.equal(await page.evaluate(`window.term.buffer.active.getLine(0).getCell(5)`), undefined);
+        assert.equal(await page.evaluate(`window.term.buffer.active.getLine(0).getCell(0).getChars()`), '');
+        assert.equal(await page.evaluate(`window.term.buffer.active.getLine(0).getCell(0).getWidth()`), 1);
         await writeSync(page, 'a文');
-        assert.equal(await page.evaluate(`window.term.buffer.getLine(0).getCell(0).getChars()`), 'a');
-        assert.equal(await page.evaluate(`window.term.buffer.getLine(0).getCell(0).getWidth()`), 1);
-        assert.equal(await page.evaluate(`window.term.buffer.getLine(0).getCell(1).getChars()`), '文');
-        assert.equal(await page.evaluate(`window.term.buffer.getLine(0).getCell(1).getWidth()`), 2);
-        assert.equal(await page.evaluate(`window.term.buffer.getLine(0).getCell(2).getChars()`), '');
-        assert.equal(await page.evaluate(`window.term.buffer.getLine(0).getCell(2).getWidth()`), 0);
+        assert.equal(await page.evaluate(`window.term.buffer.active.getLine(0).getCell(0).getChars()`), 'a');
+        assert.equal(await page.evaluate(`window.term.buffer.active.getLine(0).getCell(0).getWidth()`), 1);
+        assert.equal(await page.evaluate(`window.term.buffer.active.getLine(0).getCell(1).getChars()`), '文');
+        assert.equal(await page.evaluate(`window.term.buffer.active.getLine(0).getCell(1).getWidth()`), 2);
+        assert.equal(await page.evaluate(`window.term.buffer.active.getLine(0).getCell(2).getChars()`), '');
+        assert.equal(await page.evaluate(`window.term.buffer.active.getLine(0).getCell(2).getWidth()`), 0);
       });
     });
   });
@@ -634,7 +634,7 @@ describe('API Integration Tests', function(): void {
             window.calls.push('provide ' + position.x + ',' + position.y);
             cb({
               range: { start: position, end: position },
-              text: window.term.buffer.getLine(position.y - 1).getCell(position.x - 1).getChars(),
+              text: window.term.buffer.active.getLine(position.y - 1).getCell(position.x - 1).getChars(),
               activate: (_, text) => window.calls.push('activate ' + text),
               hover: () => window.calls.push('hover'),
               leave: () => window.calls.push('leave')

typings/xterm.d.ts

@@ -574,12 +574,7 @@ declare module 'xterm' {
      * normal buffer or the alt buffer depending on what's running in the
      * terminal.
      */
-    readonly buffer: IBuffer;
-
-    /**
-     * (EXPERIMENTAL) The terminal's current bufferSet.
-     */
-    readonly buffers: IBufferSet;
+    readonly buffer: IBufferNamespace;
 
     /**
      * (EXPERIMENTAL) Get all markers registered against the buffer. If the alt
@@ -1173,6 +1168,10 @@ declare module 'xterm' {
    * Represents a terminal buffer.
    */
   interface IBuffer {
+    /**
+     * The type of the buffer.
+     */
+    readonly type: 'normal' | 'alternate';
     /**
      * The y position of the cursor. This ranges between `0` (when the
      * cursor is at baseY) and `Terminal.rows - 1` (when the cursor is on the
@@ -1222,12 +1221,12 @@ declare module 'xterm' {
     getNullCell(): IBufferCell;
   }
 
-  interface IBufferSet {
-    readonly alt: IBuffer;
+  interface IBufferNamespace {
+    readonly alternate: IBuffer;
     readonly normal: IBuffer;
     readonly active: IBuffer;
 
-    onBufferActivate: IEvent<{ activeBuffer: IBuffer, inactiveBuffer: IBuffer }>;
+    onBufferChange: IEvent<IBuffer>;
   }
 
   /**