Fix lldb-dap path on Darwin (#1008)

* Fix lldb-dap path on Darwin

The `lldb-dap` binary is not in the toolchain directory on Darwin like
it is on Linux and Windows. Use `xcrun -find lldb-dap` on Darwin to find
the correct `lldb-dap` location.

Author: plemarquand

Diff for: src/configuration.ts

@@ -50,7 +50,7 @@ export interface DebuggerConfiguration {
     /** Are we using debug adapter provided with Toolchain */
     readonly useDebugAdapterFromToolchain: boolean;
     /** Return path to debug adapter */
-    readonly debugAdapterPath: string;
+    readonly customDebugAdapterPath: string;
 }
 
 /** workspace folder configuration */
@@ -149,7 +149,7 @@ const configuration = {
                     .getConfiguration("swift.debugger")
                     .get<boolean>("useDebugAdapterFromToolchain", false);
             },
-            get debugAdapterPath(): string {
+            get customDebugAdapterPath(): string {
                 return vscode.workspace.getConfiguration("swift.debugger").get<string>("path", "");
             },
         };

Diff for: src/debugger/debugAdapter.ts

@@ -18,6 +18,7 @@ import contextKeys from "../contextKeys";
 import { fileExists } from "../utilities/filesystem";
 import { Version } from "../utilities/version";
 import { WorkspaceContext } from "../WorkspaceContext";
+import { SwiftToolchain } from "../toolchain/toolchain";
 
 /**
  * Class managing which debug adapter we are using. Will only setup lldb-vscode/lldb-dap if it is available.
@@ -33,10 +34,25 @@ export class DebugAdapter {
     }
 
     /** Return debug adapter for toolchain */
-    public static getDebugAdapter(swiftVersion: Version): string {
+    public static getDebugAdapter(swiftVersion: Version): "lldb-vscode" | "lldb-dap" {
         return swiftVersion.isLessThan(new Version(6, 0, 0)) ? "lldb-vscode" : "lldb-dap";
     }
 
+    /** Return the path to the debug adapter */
+    public static async debugAdapterPath(toolchain: SwiftToolchain): Promise<string> {
+        const customDebugAdapterPath = configuration.debugger.customDebugAdapterPath;
+        if (customDebugAdapterPath.length > 0) {
+            return customDebugAdapterPath;
+        }
+
+        const debugAdapter = this.getDebugAdapter(toolchain.swiftVersion);
+        if (process.platform === "darwin" && debugAdapter === "lldb-dap") {
+            return await toolchain.getLLDBDebugAdapter();
+        } else {
+            return toolchain.getToolchainExecutable(debugAdapter);
+        }
+    }
+
     /**
      * Verify that the toolchain debug adapter exists
      * @param workspace WorkspaceContext
@@ -47,18 +63,15 @@ export class DebugAdapter {
         workspace: WorkspaceContext,
         quiet = false
     ): Promise<boolean> {
-        const useCustom = configuration.debugger.debugAdapterPath.length > 0;
-        const debugAdapter = DebugAdapter.getDebugAdapter(workspace.toolchain.swiftVersion);
-        const lldbDebugAdapterPath = useCustom
-            ? configuration.debugger.debugAdapterPath
-            : workspace.toolchain.getToolchainExecutable(debugAdapter);
+        const lldbDebugAdapterPath = await this.debugAdapterPath(workspace.toolchain);
 
         if (!(await fileExists(lldbDebugAdapterPath))) {
             if (!quiet) {
+                const debugAdapterName = this.getDebugAdapter(workspace.toolchain.swiftVersion);
                 vscode.window.showErrorMessage(
-                    useCustom
-                        ? `Cannot find ${debugAdapter} debug adapter specified in setting Swift.Debugger.Path.`
-                        : `Cannot find ${debugAdapter} debug adapter in your Swift toolchain.`
+                    configuration.debugger.customDebugAdapterPath.length > 0
+                        ? `Cannot find ${debugAdapterName} debug adapter specified in setting Swift.Debugger.Path.`
+                        : `Cannot find ${debugAdapterName} debug adapter in your Swift toolchain.`
                 );
             }
             workspace.outputChannel.log(`Failed to find ${lldbDebugAdapterPath}`);

Diff for: src/debugger/debugAdapterFactory.ts

@@ -14,7 +14,6 @@
 
 import * as vscode from "vscode";
 import { WorkspaceContext } from "../WorkspaceContext";
-import configuration from "../configuration";
 import { DebugAdapter } from "./debugAdapter";
 
 export function registerLLDBDebugAdapter(workspaceContext: WorkspaceContext): vscode.Disposable {
@@ -23,23 +22,16 @@ export function registerLLDBDebugAdapter(workspaceContext: WorkspaceContext): vs
             _session: vscode.DebugSession,
             executable: vscode.DebugAdapterExecutable | undefined
         ): vscode.ProviderResult<vscode.DebugAdapterDescriptor> {
-            // use the executable specified in the settings or use version in toolchain
-            const debugAdapter = DebugAdapter.getDebugAdapter(
-                workspaceContext.toolchain.swiftVersion
-            );
-            if (!executable) {
-                const lldbDebugAdapterPath =
-                    configuration.debugger.debugAdapterPath.length > 0
-                        ? configuration.debugger.debugAdapterPath
-                        : workspaceContext.toolchain.getToolchainExecutable(debugAdapter);
-                DebugAdapter.verifyDebugAdapterExists(workspaceContext).then(() => {
-                    /** Ignore */
-                });
-                executable = new vscode.DebugAdapterExecutable(lldbDebugAdapterPath, [], {});
+            if (executable) {
+                // make VS Code launch the debug adapter executable
+                return executable;
             }
 
-            // make VS Code launch the debug adapter executable
-            return executable;
+            return DebugAdapter.debugAdapterPath(workspaceContext.toolchain)
+                .then(path =>
+                    DebugAdapter.verifyDebugAdapterExists(workspaceContext).then(() => path)
+                )
+                .then(path => new vscode.DebugAdapterExecutable(path, [], {}));
         }
     }
 

Diff for: src/toolchain/toolchain.ts

@@ -354,28 +354,57 @@ export class SwiftToolchain {
     }
 
     /**
-     * Cannot use `getToolchainExecutable` to get the LLDB executable as LLDB
-     * is not in macOS toolchain path
+     * Returns the path to the LLDB executable inside the selected toolchain.
+     * If the user is on macOS and has no OSS toolchain selected, also search
+     * inside Xcode.
+     * @returns The path to the `lldb` executable
+     * @throws Throws an error if the executable cannot be found
      */
     public async getLLDB(): Promise<string> {
-        let lldbPath = path.join(
+        return this.findToolchainOrXcodeExecutable("lldb");
+    }
+
+    /**
+     * Returns the path to the LLDB debug adapter executable inside the selected
+     * toolchain. If the user is on macOS and has no OSS toolchain selected, also
+     * search inside Xcode.
+     * @returns The path to the `lldb-dap` executable
+     * @throws Throws an error if the executable cannot be found
+     */
+    public async getLLDBDebugAdapter(): Promise<string> {
+        return this.findToolchainOrXcodeExecutable("lldb-dap");
+    }
+
+    /**
+     * Search for the supplied executable in the toolchain.
+     * If the user is on macOS and has no OSS toolchain selected, also
+     * search inside Xcode.
+     */
+    private async findToolchainOrXcodeExecutable(executable: string): Promise<string> {
+        const toolchainExecutablePath = path.join(
             this.swiftFolderPath,
-            process.platform === "win32" ? "lldb.exe" : "lldb"
+            process.platform === "win32" ? `${executable}.exe` : executable
         );
-        if (!(await pathExists(lldbPath))) {
-            if (process.platform !== "darwin") {
-                throw new Error("Failed to find LLDB in swift toolchain");
-            }
-            const xcodeDirectory = SwiftToolchain.getXcodeDirectory(this.swiftFolderPath);
-            if (!xcodeDirectory) {
-                throw new Error("Failed to find LLDB in swift toolchain");
-            }
-            const { stdout } = await execFile("xcrun", ["-find", "lldb"], {
-                env: { ...process.env, DEVELOPER_DIR: xcodeDirectory },
-            });
-            lldbPath = stdout.trimEnd();
+
+        if (await pathExists(toolchainExecutablePath)) {
+            return toolchainExecutablePath;
         }
-        return lldbPath;
+
+        if (process.platform !== "darwin") {
+            throw new Error(`Failed to find ${executable} in swift toolchain`);
+        }
+        return this.findXcodeExecutable(executable);
+    }
+
+    private async findXcodeExecutable(executable: string): Promise<string> {
+        const xcodeDirectory = SwiftToolchain.getXcodeDirectory(this.toolchainPath);
+        if (!xcodeDirectory) {
+            throw new Error(`Failed to find ${executable} in Swift toolchain`);
+        }
+        const { stdout } = await execFile("xcrun", ["-find", executable], {
+            env: { ...process.env, DEVELOPER_DIR: xcodeDirectory },
+        });
+        return stdout.trimEnd();
     }
 
     private basePlatformDeveloperPath(): string | undefined {