Joh/ministerial-swan (#212096)

* first cut of embeddings API

https://github.com/microsoft/vscode/issues/212083

* add event

* fix tests

src/vs/workbench/api/common/extHostEmbedding.ts

@@ -0,0 +1,92 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import { CancellationToken } from 'vs/base/common/cancellation';
+import { Emitter, Event } from 'vs/base/common/event';
+import { IDisposable, toDisposable } from 'vs/base/common/lifecycle';
+import { IExtensionDescription } from 'vs/platform/extensions/common/extensions';
+import { ExtHostEmbeddingsShape, IMainContext, MainContext, MainThreadEmbeddingsShape } from 'vs/workbench/api/common/extHost.protocol';
+import type * as vscode from 'vscode';
+
+
+export class ExtHostEmbeddings implements ExtHostEmbeddingsShape {
+
+	private readonly _proxy: MainThreadEmbeddingsShape;
+	private readonly _provider = new Map<number, { id: string; provider: vscode.EmbeddingsProvider }>();
+
+	private readonly _onDidChange = new Emitter<void>();
+	readonly onDidChange: Event<void> = this._onDidChange.event;
+
+	private _allKnownModels = new Set<string>();
+	private _handlePool: number = 0;
+
+	constructor(
+		mainContext: IMainContext
+	) {
+		this._proxy = mainContext.getProxy(MainContext.MainThreadEmbeddings);
+	}
+
+	registerEmbeddingsProvider(_extension: IExtensionDescription, embeddingsModel: string, provider: vscode.EmbeddingsProvider): IDisposable {
+		if (this._allKnownModels.has(embeddingsModel)) {
+			throw new Error('An embeddings provider for this model is already registered');
+		}
+
+		const handle = this._handlePool++;
+
+		this._proxy.$registerEmbeddingProvider(handle, embeddingsModel);
+		this._provider.set(handle, { id: embeddingsModel, provider });
+
+		return toDisposable(() => {
+			this._proxy.$unregisterEmbeddingProvider(handle);
+			this._provider.delete(handle);
+		});
+	}
+
+	async computeEmbeddings(embeddingsModel: string, input: string, token?: vscode.CancellationToken): Promise<vscode.Embedding>;
+	async computeEmbeddings(embeddingsModel: string, input: string[], token?: vscode.CancellationToken): Promise<vscode.Embedding[]>;
+	async computeEmbeddings(embeddingsModel: string, input: string | string[], token?: vscode.CancellationToken): Promise<vscode.Embedding[] | vscode.Embedding> {
+
+		token ??= CancellationToken.None;
+
+		let returnSingle = false;
+		if (typeof input === 'string') {
+			input = [input];
+			returnSingle = true;
+		}
+		const result = await this._proxy.$computeEmbeddings(embeddingsModel, input, token);
+		if (result.length !== input.length) {
+			throw new Error();
+		}
+		if (returnSingle) {
+			if (result.length !== 1) {
+				throw new Error();
+			}
+			return result[0];
+		}
+		return result;
+
+	}
+
+	async $provideEmbeddings(handle: number, input: string[], token: CancellationToken): Promise<{ values: number[] }[]> {
+		const data = this._provider.get(handle);
+		if (!data) {
+			return [];
+		}
+		const result = await data.provider.provideEmbeddings(input, token);
+		if (!result) {
+			return [];
+		}
+		return result;
+	}
+
+	get embeddingsModels(): string[] {
+		return Array.from(this._allKnownModels);
+	}
+
+	$acceptEmbeddingModels(models: string[]): void {
+		this._allKnownModels = new Set(models);
+		this._onDidChange.fire();
+	}
+}