Allow other VS Code extensions to install LSP middleware on language feature responses

.dprint.jsonc

@@ -48,8 +48,8 @@
         "**/testdata",
         "packages/vscode-typescript/l10n/**",
         "tsc/internal/bundled/libs/**",
-        "tsc/internal/lsp/lsproto/_generate/*.json",
-        "tsc/internal/lsp/lsproto/_generate/metaModelSchema.mts",
+        "tools/scripts/lsp/*.json",
+        "tools/scripts/lsp/metaModelSchema.mts",
         // Needs to be LF to have a working shebang.
         "packages/typescript/bin/tsc",
         "tsc/internal/bundled/source/**",

Herebyfile.mjs

@@ -613,32 +613,47 @@ export const generateExtensionTest = task({
 
 async function runGenerateLSP() {
     const { GeneratedFile } = await import("./tools/scripts/gen/generatedFile.mts");
-    const directory = path.join(__dirname, "tsc/internal/lsp/lsproto/_generate");
+    const directory = path.join(__dirname, "tools/scripts/lsp");
     const modelFiles = ["metaModel.json", "metaModelSchema.mts"].map(file => new GeneratedFile(path.join(directory, file), [path.join(directory, "fetchModel.mts"), path.join(__dirname, "package-lock.json")]));
     if (!modelFiles.every(file => file.isCurrent(!!options.force))) {
         for (const file of modelFiles) file.invalidate();
-        const { default: fetchModel } = await import("./tsc/internal/lsp/lsproto/_generate/fetchModel.mts");
+        const { default: fetchModel } = await import("./tools/scripts/lsp/fetchModel.mts");
         await fetchModel();
         for (const file of modelFiles) file.markCurrent();
     }
-    const output = new GeneratedFile(path.join(directory, "../lsp_generated.go"), [
+    const output = new GeneratedFile(path.join(__dirname, "tsc/internal/lsp/lsproto/lsp_generated.go"), [
         __filename,
         path.join(directory, "generate.mts"),
         ...modelFiles.map(file => file.fileName),
     ]);
-    if (output.isCurrent(!!options.force)) {
+    if (!output.isCurrent(!!options.force)) {
+        output.invalidate();
+        const { default: generate } = await import("./tools/scripts/lsp/generate.mts");
+        await generate();
+        output.markCurrent();
+    }
+    else {
         console.log("LSP bindings are up to date.");
-        return;
     }
-    output.invalidate();
-    const { default: generate } = await import("./tsc/internal/lsp/lsproto/_generate/generate.mts");
-    await generate();
-    output.markCurrent();
+    const typeScriptOutput = new GeneratedFile(path.join(__dirname, "packages/typescript/src/vscode/protocol.generated.ts"), [
+        __filename,
+        path.join(directory, "generate.mts"),
+        path.join(directory, "generateTypeScript.mts"),
+        path.join(directory, "typeScript.mts"),
+        path.join(__dirname, "packages/vscode-typescript/src/lspMiddleware.ts"),
+        ...modelFiles.map(file => file.fileName),
+    ]);
+    if (!typeScriptOutput.isCurrent(!!options.force)) {
+        typeScriptOutput.invalidate();
+        const { default: generate } = await import("./tools/scripts/lsp/generateTypeScript.mts");
+        await generate();
+        typeScriptOutput.markCurrent();
+    }
 }
 
 export const generateLSP = task({
     name: "generate:lsp",
-    description: "Generates LSP bindings from the pinned protocol model. Pass --force to regenerate unchanged files.",
+    description: "Generates Go LSP bindings and extension API types from the pinned protocol model. Pass --force to regenerate unchanged files.",
     run: runGenerateLSP,
 });
 
@@ -1315,7 +1330,7 @@ export const checkVsceVersion = task({
 const scriptTsconfigs = [
     "./tools/scripts/gen/tsconfig.json",
     "./tools/scripts/tsc/tsconfig.json",
-    "./tsc/internal/lsp/lsproto/_generate/tsconfig.json",
+    "./tools/scripts/lsp/tsconfig.json",
 ];
 
 export const checkScripts = task({

packages/typescript/package.json

@@ -41,6 +41,9 @@
         "./schemas/tsconfig.schema.json": "./schemas/tsconfig.schema.json",
         "./schemas/jsconfig.schema.json": "./schemas/jsconfig.schema.json",
         ".": "./lib/version.cjs",
+        "./unstable/vscode": {
+            "types": "./dist/vscode/extensionApi.d.ts"
+        },
         "./unstable/sync": {
             "@typescript/source": "./src/api/sync/api.ts",
             "default": "./dist/api/sync/api.js"

packages/typescript/src/vscode/extensionApi.ts

@@ -0,0 +1,69 @@
+import type { LspMiddlewareRequests } from "./protocol.generated.ts";
+export type * from "./protocol.generated.ts";
+
+export interface Disposable {
+    dispose(): unknown;
+}
+
+export interface Event<T> {
+    (listener: (event: T) => unknown, thisArgs?: unknown, disposables?: Disposable[] | undefined): Disposable;
+}
+
+/** The URI properties used when launching a content mapper. */
+export interface ContentMapperUri {
+    readonly scheme: string;
+    readonly fsPath: string;
+}
+
+export interface ContentMapperManifest {
+    readonly name: string;
+    readonly version?: string | undefined;
+    readonly exec: readonly string[];
+    readonly cwd?: ContentMapperUri | undefined;
+    readonly compilerOptions?: readonly string[] | undefined;
+    readonly dynamicConfig?: boolean | undefined;
+}
+
+export interface ContentMapperContribution {
+    readonly extensions: readonly string[];
+    readonly inferredProjectContribution?: {
+        readonly options?: Readonly<Record<string, unknown>> | undefined;
+        readonly manifest: ContentMapperManifest;
+    } | undefined;
+}
+
+export type LspMiddlewareMethod = keyof LspMiddlewareRequests;
+
+export type DeepReadonly<T> = unknown extends T ? unknown : T extends object ? { readonly [K in keyof T]: DeepReadonly<T[K]>; } : T;
+
+export type LspMiddlewareResult<M extends LspMiddlewareMethod> = LspMiddlewareRequests[M]["result"];
+
+export type LspMiddlewareContext<M extends LspMiddlewareMethod> = { readonly params: DeepReadonly<LspMiddlewareRequests[M]["params"]>; };
+
+export type LspMiddlewareTransformer<M extends LspMiddlewareMethod> = (
+    result: LspMiddlewareResult<M>,
+    context: LspMiddlewareContext<M>,
+) => LspMiddlewareResult<M> | PromiseLike<LspMiddlewareResult<M>>;
+
+export interface ExtensionAPI {
+    onLanguageServerInitialized: Event<void>;
+    initializeAPIConnection(pipe?: string): Promise<string>;
+    registerContentMappers(contributorId: string, contributions: readonly ContentMapperContribution[]): Disposable;
+
+    /**
+     * Changes an LSP language-feature response before conversion to VS Code objects.
+     * Each callback gets its own copy of the request parameters.
+     *
+     * Callbacks run in registration order. Order between extensions may vary.
+     * If a callback fails, we log the error and use the original server response.
+     *
+     * Registrations survive server restarts. Disposing removes the callback from
+     * future responses but does not interrupt a response already being processed.
+     *
+     * Requests, notifications, lifecycle messages, and partial results are excluded.
+     */
+    registerLspMiddleware<M extends LspMiddlewareMethod>(
+        method: M,
+        transformer: LspMiddlewareTransformer<NoInfer<M>>,
+    ): Disposable;
+}