Introduces codeEditorObs (#210938)

* Introduces obsCodeEditor

src/vs/editor/browser/observableUtilities.ts

@@ -0,0 +1,71 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import { IDisposable, DisposableStore } from 'vs/base/common/lifecycle';
+import { autorunOpts, derivedOpts, IObservable, observableFromEvent } from 'vs/base/common/observable';
+import { ICodeEditor } from 'vs/editor/browser/editorBrowser';
+import { Position } from 'vs/editor/common/core/position';
+import { IModelDeltaDecoration } from 'vs/editor/common/model';
+
+/**
+ * Returns a facade for the code editor that provides observables for various states/events.
+*/
+export function obsCodeEditor(editor: ICodeEditor): ObservableCodeEditor {
+	return ObservableCodeEditor.get(editor);
+}
+
+class ObservableCodeEditor {
+	private static _map = new Map<ICodeEditor, ObservableCodeEditor>();
+
+	/**
+	 * Make sure that editor is not disposed yet!
+	*/
+	public static get(editor: ICodeEditor): ObservableCodeEditor {
+		let result = ObservableCodeEditor._map.get(editor);
+		if (!result) {
+			result = new ObservableCodeEditor(editor);
+			ObservableCodeEditor._map.set(editor, result);
+			const d = editor.onDidDispose(() => {
+				ObservableCodeEditor._map.delete(editor);
+				d.dispose();
+			});
+		}
+		return result;
+	}
+
+	private constructor(public readonly editor: ICodeEditor) {
+	}
+
+	public readonly model = observableFromEvent(this.editor.onDidChangeModel, () => this.editor.getModel());
+	public readonly value = observableFromEvent(this.editor.onDidChangeModelContent, () => this.editor.getValue());
+	public readonly valueIsEmpty = observableFromEvent(this.editor.onDidChangeModelContent, () => this.editor.getModel()?.getValueLength() === 0);
+	public readonly selections = observableFromEvent(this.editor.onDidChangeCursorSelection, () => this.editor.getSelections());
+	public readonly cursorPosition = derivedOpts({ owner: this, equalsFn: Position.equals }, reader => this.selections.read(reader)?.[0]?.getPosition() ?? null);
+	public readonly isFocused = observableFromEvent(e => {
+		const d1 = this.editor.onDidFocusEditorWidget(e);
+		const d2 = this.editor.onDidBlurEditorWidget(e);
+		return {
+			dispose() {
+				d1.dispose();
+				d2.dispose();
+			}
+		};
+	}, () => this.editor.hasWidgetFocus());
+
+	public setDecorations(decorations: IObservable<IModelDeltaDecoration[]>): IDisposable {
+		const d = new DisposableStore();
+		const decorationsCollection = this.editor.createDecorationsCollection();
+		d.add(autorunOpts({ owner: this, debugName: () => `Apply decorations from ${decorations.debugName}` }, reader => {
+			const d = decorations.read(reader);
+			decorationsCollection.set(d);
+		}));
+		d.add({
+			dispose: () => {
+				decorationsCollection.clear();
+			}
+		});
+		return d;
+	}
+}

src/vs/editor/browser/widget/diffEditor/components/diffEditorEditors.ts

@@ -3,11 +3,12 @@
  *  Licensed under the MIT License. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
 
-import { Emitter, Event } from 'vs/base/common/event';
+import { Emitter } from 'vs/base/common/event';
 import { Disposable } from 'vs/base/common/lifecycle';
 import { IReader, autorunHandleChanges, derived, derivedOpts, observableFromEvent } from 'vs/base/common/observable';
 import { IEditorConstructionOptions } from 'vs/editor/browser/config/editorConfiguration';
 import { IDiffEditorConstructionOptions } from 'vs/editor/browser/editorBrowser';
+import { obsCodeEditor } from 'vs/editor/browser/observableUtilities';
 import { CodeEditorWidget, ICodeEditorWidgetOptions } from 'vs/editor/browser/widget/codeEditor/codeEditorWidget';
 import { IDiffCodeEditorWidgetOptions } from 'vs/editor/browser/widget/diffEditor/diffEditorWidget';
 import { OverviewRulerFeature } from 'vs/editor/browser/widget/diffEditor/features/overviewRulerFeature';
@@ -29,15 +30,15 @@ export class DiffEditorEditors extends Disposable {
 	public readonly modifiedScrollTop = observableFromEvent(this.modified.onDidScrollChange, () => /** @description modified.getScrollTop */ this.modified.getScrollTop());
 	public readonly modifiedScrollHeight = observableFromEvent(this.modified.onDidScrollChange, () => /** @description modified.getScrollHeight */ this.modified.getScrollHeight());
 
-	public readonly modifiedModel = observableFromEvent(this.modified.onDidChangeModel, () => /** @description modified.model */ this.modified.getModel());
+	public readonly modifiedModel = obsCodeEditor(this.modified).model;
 
 	public readonly modifiedSelections = observableFromEvent(this.modified.onDidChangeCursorSelection, () => this.modified.getSelections() ?? []);
 	public readonly modifiedCursor = derivedOpts({ owner: this, equalsFn: Position.equals }, reader => this.modifiedSelections.read(reader)[0]?.getPosition() ?? new Position(1, 1));
 
 	public readonly originalCursor = observableFromEvent(this.original.onDidChangeCursorPosition, () => this.original.getPosition() ?? new Position(1, 1));
 
-	public readonly isOriginalFocused = observableFromEvent(Event.any(this.original.onDidFocusEditorWidget, this.original.onDidBlurEditorWidget), () => this.original.hasWidgetFocus());
-	public readonly isModifiedFocused = observableFromEvent(Event.any(this.modified.onDidFocusEditorWidget, this.modified.onDidBlurEditorWidget), () => this.modified.hasWidgetFocus());
+	public readonly isOriginalFocused = obsCodeEditor(this.original).isFocused;
+	public readonly isModifiedFocused = obsCodeEditor(this.modified).isFocused;
 
 	public readonly isFocused = derived(this, reader => this.isOriginalFocused.read(reader) || this.isModifiedFocused.read(reader));