Mostly implemented buffer API

Part of xtermjs#1994

src/public/Terminal.ts

@@ -3,8 +3,8 @@
  * @license MIT
  */
 
-import { Terminal as ITerminalApi, ITerminalOptions, IMarker, IDisposable, ILinkMatcherOptions, ITheme, ILocalizableStrings } from 'xterm';
-import { ITerminal } from '../Types';
+import { Terminal as ITerminalApi, ITerminalOptions, IMarker, IDisposable, ILinkMatcherOptions, ITheme, ILocalizableStrings, IBuffer as IBufferApi, IBufferLine as IBufferLineApi, IBufferCell as IBufferCellApi } from 'xterm';
+import { ITerminal, IBufferLine, IBuffer } from '../Types';
 import { Terminal as TerminalCore } from '../Terminal';
 import * as Strings from '../Strings';
 
@@ -19,6 +19,7 @@ export class Terminal implements ITerminalApi {
   public get textarea(): HTMLTextAreaElement { 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 markers(): IMarker[] { return this._core.markers; }
   public blur(): void {
     this._core.blur();
@@ -158,3 +159,30 @@ export class Terminal implements ITerminalApi {
     return Strings;
   }
 }
+
+class BufferApiView implements IBufferApi {
+  constructor(private _buffer: IBuffer) {}
+
+  public get cursorY(): number { return this._buffer.y; }
+  public get cursorX(): number { return this._buffer.x; }
+  public get viewportY(): number { return this._buffer.ydisp; }
+  public get baseY(): number { return this._buffer.ybase; }
+  public get length(): number { return this._buffer.lines.length; }
+  public getLine(y: number): IBufferLineApi { return new BufferLineApiView(this._buffer.lines.get(y)); }
+}
+
+class BufferLineApiView implements IBufferLineApi {
+  constructor(private _line: IBufferLine) {}
+
+  public get isWrapped(): boolean { return this._line.isWrapped; }
+  public getCell(x: number): IBufferCellApi { return new BufferCellApiView(this._line, x); }
+  public translateToString(trimRight: boolean, startColumn: number, endColumn: number): string {
+    return this._line.translateToString(trimRight, startColumn, endColumn);
+  }
+}
+
+class BufferCellApiView implements IBufferCellApi {
+  constructor(private _line: IBufferLine, private _x: number) {}
+  public get char(): string { return this._line.getString(this._x); }
+  public get width(): number { return this._line.getWidth(this._x); }
+}

typings/xterm.d.ts

@@ -347,6 +347,13 @@ declare module 'xterm' {
      */
     readonly cols: number;
 
+    /**
+     * (EXPERIMENTAL) The terminal's current buffer, note that this might be
+     * either the normal buffer or the alt buffer depending on what's running in
+     * the terminal.
+     */
+    readonly buffer: IBuffer;
+
     /**
      * (EXPERIMENTAL) Get all markers registered against the buffer. If the alt
      * buffer is active this will always return [].
@@ -772,4 +779,77 @@ declare module 'xterm' {
      */
     static applyAddon(addon: any): void;
   }
+
+  interface IBuffer {
+    /**
+     * 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
+     * last row).
+     */
+    readonly cursorY: number;
+
+    /**
+     * The x position of the cursor. This ranges between `0` (left side) and
+     * `Terminal.cols - 1` (right side).
+     */
+    readonly cursorX: number;
+
+    /**
+     * The line within the buffer where the top of the viewport is.
+     */
+    readonly viewportY: number;
+
+    /**
+     * The line within the buffer where the top of the bottom page is (when
+     * fully scrolled down);
+     */
+    readonly baseY: number;
+
+    /**
+     * The amount of lines in the buffer.
+     */
+    readonly length: number;
+
+    /**
+     * Gets a line from the buffer.
+     *
+     * @param y The line index to get.
+     */
+    getLine(y: number): IBufferLine;
+  }
+
+  interface IBufferLine {
+    /**
+     * Whether the line is wrapped from the previous line.
+     */
+    readonly isWrapped: boolean;
+
+    /**
+     * Gets a cell from the line.
+     *
+     * @param x The character index to get.
+     */
+    getCell(x: number): IBufferCell;
+
+    /**
+     * Gets the line
+     */
+    translateToString(trimRight: boolean, startColumn: number, endColumn: number): string;
+  }
+
+  interface IBufferCell {
+    /**
+     * The character within the cell.
+     */
+    readonly char: string;
+
+    /**
+     * The width of the character. Some examples:
+     *
+     * - This is `1` for most cells.
+     * - This is `2` for wide character like CJK glyphs.
+     * - This is `0` for cells immediately following cells with a width of `2`.
+     */
+    readonly width: number;
+  }
 }