Handle custom PeekDocumentsRequest 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 { PeekDocumentsParams, PeekDocumentsRequest } from "./lspExtensions";
 
 interface SourceKitLogMessageParams extends langclient.LogMessageParams {
     logName?: string;
@@ -559,6 +560,9 @@ export class LanguageClientManager {
                 })(),
             },
             errorHandler: new SourceKitLSPErrorHandler(5),
+            initializationOptions: {
+                "workspace/peekDocuments": true, // workaround for client capability to handle `PeekDocumentsRequest`
+            },
         };
 
         return new langclient.LanguageClient(
@@ -616,6 +620,36 @@ export class LanguageClientManager {
         this.languageClient = client;
         this.cancellationToken = new vscode.CancellationTokenSource();
 
+        this.languageClient.onRequest(
+            PeekDocumentsRequest.method,
+            async (params: PeekDocumentsParams) => {
+                const locations = params.locations.map(uri => {
+                    const location = new vscode.Location(
+                        vscode.Uri.from({
+                            scheme: "file",
+                            path: new URL(uri).pathname,
+                        }),
+                        new vscode.Position(0, 0)
+                    );
+
+                    return location;
+                });
+
+                await vscode.commands.executeCommand(
+                    "editor.action.peekLocations",
+                    vscode.Uri.from({
+                        scheme: "file",
+                        path: new URL(params.uri).pathname,
+                    }),
+                    new vscode.Position(params.position.line, params.position.character),
+                    locations,
+                    "peek"
+                );
+
+                return { success: true };
+            }
+        );
+
         return this.clientReadyPromise;
     }
 

src/sourcekit-lsp/lspExtensions.ts

@@ -14,9 +14,48 @@
 
 import * as ls from "vscode-languageserver-protocol";
 import * as langclient from "vscode-languageclient/node";
+import * as vscode from "vscode";
 
 // Definitions for non-standard requests used by sourcekit-lsp
 
+// Peek Documents
+export interface PeekDocumentsParams {
+    /**
+     * The `DocumentUri` of the text document in which to show the "peeked" editor
+     */
+    uri: langclient.DocumentUri;
+
+    /**
+     * The `Position` in the given text document in which to show the "peeked editor"
+     */
+    position: vscode.Position;
+
+    /**
+     * An array `DocumentUri` of the documents to appear inside the "peeked" editor
+     */
+    locations: langclient.DocumentUri[];
+}
+
+/**
+ * Response to indicate the `success` of the `PeekDocumentsRequest`
+ */
+export interface PeekDocumentsResult {
+    success: boolean;
+}
+
+/**
+ * Request from the server to the client to show the given documents in a "peeked" editor.
+ *
+ * This request is handled by the client to show the given documents in a "peeked" editor (i.e. inline with / inside the editor canvas).
+ *
+ * It requires the experimental client capability `"workspace/peekDocuments"` to use.
+ */
+export const PeekDocumentsRequest = new langclient.RequestType<
+    PeekDocumentsParams,
+    PeekDocumentsResult,
+    unknown
+>("workspace/peekDocuments");
+
 // Inlay Hints (pre Swift 5.6)
 export interface LegacyInlayHintsParams {
     /**