Add support to ANSI OSC52

Add support to ANSI OSC52 sequence to manipulate selection and clipboard
data. The sequence specs supports multiple clipboard selections but we
only support the common ones, system and primary clipboard selections.

This adds a new event listener to the common terminal module
`onClipboard` to allow external implementations to hook into it.

The addon uses the browser Clipboard API to read/write from and to the
clipboard. The default `ClipboardProvider` uses the browser Clipboard
API. This means it only supports read/write to and from the system
clipboard.

Reference: https://invisible-island.net/xterm/ctlseqs/ctlseqs.html#h3-Operating-System-Commands
Fixes: xtermjs#3260
Signed-off-by: Ayman Bagabas <ayman.bagabas@gmail.com>

src/common/InputHandler.ts

@@ -4,7 +4,7 @@
  * @license MIT
  */
 
-import { IInputHandler, IAttributeData, IDisposable, IWindowOptions, IColorEvent, IParseStack, ColorIndex, ColorRequestType, SpecialColorIndex } from 'common/Types';
+import { IInputHandler, IAttributeData, IDisposable, IWindowOptions, IColorEvent, IParseStack, ColorIndex, ColorRequestType, SpecialColorIndex, IClipboardEvent, ClipboardEventType } from 'common/Types';
 import { C0, C1 } from 'common/data/EscapeSequences';
 import { CHARSETS, DEFAULT_CHARSET } from 'common/data/Charsets';
 import { EscapeSequenceParser } from 'common/parser/EscapeSequenceParser';
@@ -22,6 +22,7 @@ import { OscHandler } from 'common/parser/OscParser';
 import { DcsHandler } from 'common/parser/DcsParser';
 import { IBuffer } from 'common/buffer/Types';
 import { parseColor } from 'common/input/XParseColor';
+import { ClipboardSelection } from 'xterm';
 
 /**
  * Map collect to glevel. Used in `selectCharset`.
@@ -159,6 +160,8 @@ export class InputHandler extends Disposable implements IInputHandler {
   public readonly onTitleChange = this._onTitleChange.event;
   private readonly _onColor = this.register(new EventEmitter<IColorEvent>());
   public readonly onColor = this._onColor.event;
+  private readonly _onClipboard = this.register(new EventEmitter<IClipboardEvent>());
+  public readonly onClipboard = this._onClipboard.event;
 
   private _parseStack: IParseStack = {
     paused: false,
@@ -320,6 +323,7 @@ export class InputHandler extends Disposable implements IInputHandler {
     //  50 - Set Font to Pt.
     //  51 - reserved for Emacs shell.
     //  52 - Manipulate Selection Data.
+    this._parser.registerOscHandler(52, new OscHandler(data => this.setOrReportClipboard(data)));
     // 104 ; c - Reset Color Number c.
     this._parser.registerOscHandler(104, new OscHandler(data => this.restoreIndexedColor(data)));
     // 105 ; c - Reset Special Color Number c.
@@ -3081,6 +3085,60 @@ export class InputHandler extends Disposable implements IInputHandler {
     return this._setOrReportSpecialColor(data, 2);
   }
 
+  private _setOrReportClipboard(data: string): boolean {
+    if (!this._optionsService.options.allowClipboardAccess) {
+      return true;
+    }
+    const args = data.split(';');
+    if (args.length < 2) {
+      return true;
+    }
+    const pc = args[0];
+    const pd = args[1];
+    if (pd.length === 0) {
+      return true;
+    }
+    switch (pc) {
+      case ClipboardSelection.SYSTEM:
+      case ClipboardSelection.PRIMARY:
+        this._onClipboard.fire({
+          type: pd === '?' ? ClipboardEventType.REPORT : ClipboardEventType.SET,
+          selection: pc,
+          data: pd
+        });
+        break;
+    }
+    return true;
+  }
+
+  /**
+   * OSC 52 ; <selection name> ; <base64 data>|<?> ST - set or query selection and clipboard data
+   *
+   * Test case:
+   *
+   * ```sh
+   * printf "\e]52;c;%s\a" "$(echo -n "Hello, World" | base64)"
+   * ```
+   *
+   * @vt: #Y    OSC    52    "Manipulate Selection Data"   "OSC 52 ; Pc ; Pd BEL" "Set or query selection and clipboard data."
+   * Pc is the selection name. Can be one of:
+   * - `c` - clipboard
+   * - `p` - primary
+   * - `q` - secondary
+   * - `s` - select
+   * - `0-7` - cut-buffers 0-7
+   *
+   * Only the `c` selection (clipboard) is supported by xterm.js. The browser
+   * Clipboard API only supports the clipboard selection.
+   *
+   * Pd is the base64 encoded data.
+   * If Pd is `?`, the terminal returns the current clipboard contents.
+   * If Pd is neither base64 encoded nor `?`, then the clipboard is cleared.
+   */
+  public setOrReportClipboard(data: string): boolean {
+    return this._setOrReportClipboard(data);
+  }
+
   /**
    * OSC 104 ; <num> ST - restore ANSI color <num>
    *