Handle custom PeekMacroRequest to show macro expansions in a peeked editor

Author: lokesh-tr

src/sourcekit-lsp/LanguageClientManager.ts

@@ -27,6 +27,7 @@ import { DiagnosticsManager } from "../DiagnosticsManager";
 import { LSPLogger, LSPOutputChannel } from "./LSPOutputChannel";
 import { SwiftOutputChannel } from "../ui/SwiftOutputChannel";
 import { promptForDiagnostics } from "../commands/captureDiagnostics";
+import { PeekMacroParams, PeekMacroRequest } from "./lspExtensions";
 
 interface SourceKitLogMessageParams extends langclient.LogMessageParams {
     logName?: string;
@@ -616,6 +617,37 @@ export class LanguageClientManager {
         this.languageClient = client;
         this.cancellationToken = new vscode.CancellationTokenSource();
 
+        this.languageClient.onRequest(PeekMacroRequest.method, async (params: PeekMacroParams) => {
+            const locations = params.macroExpansion.expansionURIs.map(uri => {
+                const location = new vscode.Location(
+                    vscode.Uri.from({
+                        scheme: "file",
+                        path: new URL(uri).pathname,
+                    }),
+                    new vscode.Position(0, 0)
+                );
+
+                return location;
+            });
+
+            console.log(params.peekLocation);
+
+            const peekPosition = new vscode.Position(
+                params.peekLocation.line,
+                params.peekLocation.character
+            );
+
+            await vscode.commands.executeCommand(
+                "editor.action.peekLocations",
+                vscode.window.activeTextEditor?.document.uri,
+                peekPosition,
+                locations,
+                "peek"
+            );
+
+            return { success: true };
+        });
+
         return this.clientReadyPromise;
     }
 

src/sourcekit-lsp/lspExtensions.ts

@@ -14,9 +14,30 @@
 
 import * as ls from "vscode-languageserver-protocol";
 import * as langclient from "vscode-languageclient/node";
+import { Position, Uri } from "vscode";
 
 // Definitions for non-standard requests used by sourcekit-lsp
 
+export interface PeekMacroParams {
+    macroExpansion: MacroExpansion;
+    peekLocation: Position;
+}
+
+interface MacroExpansion {
+    expansionURIs: Uri[];
+}
+
+export interface PeekMacroResult {
+    success: boolean;
+    failureReason?: string;
+}
+
+export const PeekMacroRequest = new langclient.RequestType<
+    PeekMacroParams,
+    PeekMacroResult,
+    unknown
+>("sourcekit-lsp/peekMacro");
+
 // Inlay Hints (pre Swift 5.6)
 export interface LegacyInlayHintsParams {
     /**