add process picker

Author: matthewbastien

package.json

@@ -271,6 +271,11 @@
         "title": "Run Until Failure...",
         "category": "Swift"
       },
+      {
+        "command": "swift.pickProcess",
+        "title": "Pick Process...",
+        "category": "Swift"
+      },
       {
         "command": "swift.runAllTestsParallel",
         "title": "Run Tests in Parallel",
@@ -957,6 +962,10 @@
           "command": "swift.reindexProject",
           "when": "swift.supportsReindexing"
         },
+        {
+          "command": "swift.pickProcess",
+          "when": "false"
+        },
         {
           "command": "swift.runAllTestsParallel",
           "when": "swift.isActivated"
@@ -1359,7 +1368,7 @@
         "type": "swift",
         "label": "Swift Debugger",
         "variables": {
-          "PickProcess": "lldb-dap.pickProcess"
+          "pickProcess": "swift.pickProcess"
         },
         "configurationAttributes": {
           "launch": {
@@ -1586,7 +1595,7 @@
               "type": "swift",
               "request": "attach",
               "name": "${1:Attach to Swift Executable}",
-              "pid": "^\"\\${command:PickProcess}\""
+              "pid": "^\"\\${command:pickProcess}\""
             }
           },
           {

src/commands.ts

@@ -43,6 +43,7 @@ import { runAllTests } from "./commands/runAllTests";
 import { updateDependenciesViewList } from "./commands/dependencies/updateDepViewList";
 import { runTask } from "./commands/runTask";
 import { TestKind } from "./TestExplorer/TestKind";
+import { pickProcess } from "./commands/pickProcess";
 
 /**
  * References:
@@ -65,6 +66,9 @@ export function registerToolchainCommands(
         vscode.commands.registerCommand("swift.selectToolchain", () =>
             showToolchainSelectionQuickPick(toolchain)
         ),
+        vscode.commands.registerCommand("swift.pickProcess", configuration =>
+            pickProcess(configuration)
+        ),
     ];
 }
 

src/commands/pickProcess.ts

@@ -0,0 +1,79 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the VS Code Swift open source project
+//
+// Copyright (c) 2025 the VS Code Swift project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of VS Code Swift project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import * as path from "path";
+import * as vscode from "vscode";
+import { createProcessTree } from "../process-tree";
+
+interface ProcessQuickPick extends vscode.QuickPickItem {
+    processId?: number;
+}
+
+/**
+ * Prompts the user to select a running process.
+ *
+ * The return value must be a string so that it is compatible with VS Code's
+ * string substitution infrastructure. The value will eventually be converted
+ * to a number by the debug configuration provider.
+ *
+ * @param configuration The related debug configuration, if any
+ * @returns The pid of the process as a string or undefined if cancelled.
+ */
+export async function pickProcess(
+    configuration?: vscode.DebugConfiguration
+): Promise<string | undefined> {
+    const processTree = createProcessTree();
+    const selectedProcess = await vscode.window.showQuickPick<ProcessQuickPick>(
+        processTree.listAllProcesses().then((processes): ProcessQuickPick[] => {
+            // Sort by start date in descending order
+            processes.sort((a, b) => b.start - a.start);
+            // Filter by program if requested
+            if (typeof configuration?.program === "string") {
+                const program = configuration.program;
+                const programBaseName = path.basename(program);
+                processes = processes
+                    .filter(proc => path.basename(proc.command) === programBaseName)
+                    .sort((a, b) => {
+                        // Bring exact command matches to the top
+                        const aIsExactMatch = a.command === program ? 1 : 0;
+                        const bIsExactMatch = b.command === program ? 1 : 0;
+                        return bIsExactMatch - aIsExactMatch;
+                    });
+                // Show a better message if all processes were filtered out
+                if (processes.length === 0) {
+                    return [
+                        {
+                            label: "No processes matched the debug configuration's program",
+                        },
+                    ];
+                }
+            }
+            // Convert to a QuickPickItem
+            return processes.map(proc => {
+                return {
+                    processId: proc.id,
+                    label: path.basename(proc.command),
+                    description: proc.id.toString(),
+                    detail: proc.arguments,
+                } satisfies ProcessQuickPick;
+            });
+        }),
+        {
+            placeHolder: "Select a process to attach the debugger to",
+            matchOnDetail: true,
+            matchOnDescription: true,
+        }
+    );
+    return selectedProcess?.processId?.toString();
+}

src/process-tree/BaseProcessTree.ts

@@ -0,0 +1,55 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the VS Code Swift open source project
+//
+// Copyright (c) 2025 the VS Code Swift project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of VS Code Swift project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import * as util from "util";
+import * as child_process from "child_process";
+import { Process, ProcessTree } from ".";
+
+const exec = util.promisify(child_process.execFile);
+
+/** Parses process information from a given line of process output. */
+export type ProcessTreeParser = (line: string) => Process | undefined;
+
+/**
+ * Implements common behavior between the different {@link ProcessTree} implementations.
+ */
+export abstract class BaseProcessTree implements ProcessTree {
+    /**
+     * Get the command responsible for collecting all processes on the system.
+     */
+    protected abstract getCommand(): string;
+
+    /**
+     * Get the list of arguments used to launch the command.
+     */
+    protected abstract getCommandArguments(): string[];
+
+    /**
+     * Create a new parser that can read the process information from stdout of the process
+     * spawned by {@link spawnProcess spawnProcess()}.
+     */
+    protected abstract createParser(): ProcessTreeParser;
+
+    async listAllProcesses(): Promise<Process[]> {
+        const execCommand = exec(this.getCommand(), this.getCommandArguments());
+        const parser = this.createParser();
+        return (await execCommand).stdout.split("\n").flatMap(line => {
+            const process = parser(line.toString());
+            if (!process || process.id === execCommand.child.pid) {
+                return [];
+            }
+            return [process];
+        });
+    }
+}

src/process-tree/index.ts

@@ -0,0 +1,50 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the VS Code Swift open source project
+//
+// Copyright (c) 2025 the VS Code Swift project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of VS Code Swift project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import { DarwinProcessTree } from "./platforms/DarwinProcessTree";
+import { LinuxProcessTree } from "./platforms/LinuxProcessTree";
+import { WindowsProcessTree } from "./platforms/WindowsProcessTree";
+
+/**
+ * Represents a single process running on the system.
+ */
+export interface Process {
+    /** Process ID */
+    id: number;
+
+    /** Command that was used to start the process */
+    command: string;
+
+    /** The full command including arguments that was used to start the process */
+    arguments: string;
+
+    /** The date when the process was started */
+    start: number;
+}
+
+export interface ProcessTree {
+    listAllProcesses(): Promise<Process[]>;
+}
+
+/** Returns a {@link ProcessTree} based on the current platform. */
+export function createProcessTree(): ProcessTree {
+    switch (process.platform) {
+        case "darwin":
+            return new DarwinProcessTree();
+        case "win32":
+            return new WindowsProcessTree();
+        default:
+            return new LinuxProcessTree();
+    }
+}

src/process-tree/platforms/DarwinProcessTree.ts

@@ -0,0 +1,25 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the VS Code Swift open source project
+//
+// Copyright (c) 2025 the VS Code Swift project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of VS Code Swift project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import { LinuxProcessTree } from "./LinuxProcessTree";
+
+export class DarwinProcessTree extends LinuxProcessTree {
+    protected override getCommandArguments(): string[] {
+        return [
+            "-axo",
+            // The length of comm must be large enough or data will be truncated.
+            `pid=PID,state=STATE,lstart=START,comm=${"COMMAND".padEnd(256, "-")},args=ARGUMENTS`,
+        ];
+    }
+}

src/process-tree/platforms/LinuxProcessTree.ts

@@ -0,0 +1,65 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the VS Code Swift open source project
+//
+// Copyright (c) 2025 the VS Code Swift project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of VS Code Swift project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import { BaseProcessTree, ProcessTreeParser } from "../BaseProcessTree";
+
+export class LinuxProcessTree extends BaseProcessTree {
+    protected override getCommand(): string {
+        return "ps";
+    }
+
+    protected override getCommandArguments(): string[] {
+        return [
+            "-axo",
+            // The length of exe must be large enough or data will be truncated.
+            `pid=PID,state=STATE,lstart=START,exe:128=COMMAND,args=ARGUMENTS`,
+        ];
+    }
+
+    protected override createParser(): ProcessTreeParser {
+        let commandOffset: number | undefined;
+        let argumentsOffset: number | undefined;
+        return line => {
+            if (!commandOffset || !argumentsOffset) {
+                commandOffset = line.indexOf("COMMAND");
+                argumentsOffset = line.indexOf("ARGUMENTS");
+                return;
+            }
+
+            const pidAndState = /^\s*([0-9]+)\s+([a-zA-Z<>+]+)\s+/.exec(line);
+            if (!pidAndState) {
+                return;
+            }
+
+            // Make sure the process isn't in a trace/debug or zombie state as we cannot attach to them
+            const state = pidAndState[2];
+            if (state.includes("X") || state.includes("Z")) {
+                return;
+            }
+
+            // ps will list "-" as the command if it does not know where the executable is located
+            const command = line.slice(commandOffset, argumentsOffset).trim();
+            if (command === "-") {
+                return;
+            }
+
+            return {
+                id: Number(pidAndState[1]),
+                command,
+                arguments: line.slice(argumentsOffset).trim(),
+                start: Date.parse(line.slice(pidAndState[0].length, commandOffset).trim()),
+            };
+        };
+    }
+}

src/process-tree/platforms/WindowsProcessTree.ts

@@ -0,0 +1,61 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the VS Code Swift open source project
+//
+// Copyright (c) 2025 the VS Code Swift project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of VS Code Swift project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import { BaseProcessTree, ProcessTreeParser } from "../BaseProcessTree";
+
+export class WindowsProcessTree extends BaseProcessTree {
+    protected override getCommand(): string {
+        return "PowerShell";
+    }
+
+    protected override getCommandArguments(): string[] {
+        return [
+            "-Command",
+            'Get-CimInstance -ClassName Win32_Process | Format-Table ProcessId, @{Label="CreationDate";Expression={"{0:yyyyMddHHmmss}" -f $_.CreationDate}}, CommandLine | Out-String -width 9999',
+        ];
+    }
+
+    protected override createParser(): ProcessTreeParser {
+        const lineRegex = /^([0-9]+)\s+([0-9]+)\s+(.*)$/;
+
+        return line => {
+            const matches = lineRegex.exec(line.trim());
+            if (!matches || matches.length !== 4) {
+                return;
+            }
+
+            const id = Number(matches[1]);
+            const start = Number(matches[2]);
+            const fullCommandLine = matches[3].trim();
+            if (isNaN(id) || !fullCommandLine) {
+                return;
+            }
+            // Extract the command from the full command line
+            let command = fullCommandLine;
+            if (fullCommandLine[0] === '"') {
+                const end = fullCommandLine.indexOf('"', 1);
+                if (end > 0) {
+                    command = fullCommandLine.slice(1, end);
+                }
+            } else {
+                const end = fullCommandLine.indexOf(" ");
+                if (end > 0) {
+                    command = fullCommandLine.slice(0, end);
+                }
+            }
+
+            return { id, command, arguments: fullCommandLine, start };
+        };
+    }
+}