SQL Operations Studio Public Preview 1 (0.23) release source code

src/vs/editor/contrib/cursorUndo/browser/cursorUndo.ts

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+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the Source EULA. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+'use strict';
+
+import { Selection } from 'vs/editor/common/core/selection';
+import { editorCommand, ServicesAccessor, EditorCommand } from 'vs/editor/common/editorCommonExtensions';
+import { KeyCode, KeyMod } from 'vs/base/common/keyCodes';
+import { Disposable } from 'vs/base/common/lifecycle';
+import { ICommonCodeEditor, IEditorContribution } from 'vs/editor/common/editorCommon';
+import { EditorContextKeys } from 'vs/editor/common/editorContextKeys';
+import { ICodeEditor } from 'vs/editor/browser/editorBrowser';
+import { editorContribution } from 'vs/editor/browser/editorBrowserExtensions';
+
+class CursorState {
+	readonly selections: Selection[];
+
+	constructor(selections: Selection[]) {
+		this.selections = selections;
+	}
+
+	public equals(other: CursorState): boolean {
+		const thisLen = this.selections.length;
+		const otherLen = other.selections.length;
+		if (thisLen !== otherLen) {
+			return false;
+		}
+		for (let i = 0; i < thisLen; i++) {
+			if (!this.selections[i].equalsSelection(other.selections[i])) {
+				return false;
+			}
+		}
+		return true;
+	}
+}
+
+@editorContribution
+export class CursorUndoController extends Disposable implements IEditorContribution {
+
+	private static ID = 'editor.contrib.cursorUndoController';
+
+	public static get(editor: ICommonCodeEditor): CursorUndoController {
+		return editor.getContribution<CursorUndoController>(CursorUndoController.ID);
+	}
+
+	private readonly _editor: ICodeEditor;
+	private _isCursorUndo: boolean;
+
+	private _undoStack: CursorState[];
+	private _prevState: CursorState;
+
+	constructor(editor: ICodeEditor) {
+		super();
+		this._editor = editor;
+		this._isCursorUndo = false;
+
+		this._undoStack = [];
+		this._prevState = this._readState();
+
+		this._register(editor.onDidChangeModel((e) => {
+			this._undoStack = [];
+			this._prevState = null;
+		}));
+		this._register(editor.onDidChangeModelContent((e) => {
+			this._undoStack = [];
+			this._prevState = null;
+		}));
+		this._register(editor.onDidChangeCursorSelection((e) => {
+
+			if (!this._isCursorUndo && this._prevState) {
+				this._undoStack.push(this._prevState);
+				if (this._undoStack.length > 50) {
+					// keep the cursor undo stack bounded
+					this._undoStack = this._undoStack.splice(0, this._undoStack.length - 50);
+				}
+			}
+
+			this._prevState = this._readState();
+		}));
+	}
+
+	private _readState(): CursorState {
+		if (!this._editor.getModel()) {
+			// no model => no state
+			return null;
+		}
+
+		return new CursorState(this._editor.getSelections());
+	}
+
+	public getId(): string {
+		return CursorUndoController.ID;
+	}
+
+	public cursorUndo(): void {
+		const currState = new CursorState(this._editor.getSelections());
+
+		while (this._undoStack.length > 0) {
+			const prevState = this._undoStack.pop();
+
+			if (!prevState.equals(currState)) {
+				this._isCursorUndo = true;
+				this._editor.setSelections(prevState.selections);
+				this._isCursorUndo = false;
+				return;
+			}
+		}
+	}
+}
+
+@editorCommand
+export class CursorUndo extends EditorCommand {
+	constructor() {
+		super({
+			id: 'cursorUndo',
+			precondition: null,
+			kbOpts: {
+				kbExpr: EditorContextKeys.textFocus,
+				primary: KeyMod.CtrlCmd | KeyCode.KEY_U
+			}
+		});
+	}
+
+	public runEditorCommand(accessor: ServicesAccessor, editor: ICommonCodeEditor, args: any): void {
+		CursorUndoController.get(editor).cursorUndo();
+	}
+}