Implement Claude Code basics

utils/subprocess.ts

@@ -0,0 +1,117 @@
+import { spawn as nodeSpawn } from "node:child_process";
+
+export interface SpawnOptions {
+  cmd: string;
+  args: string[];
+  env?: Record<string, string>;
+  input?: string;
+  timeout?: number;
+  onStdout?: (chunk: string) => void;
+  onStderr?: (chunk: string) => void;
+}
+
+export interface SpawnResult {
+  stdout: string;
+  stderr: string;
+  exitCode: number;
+  durationMs: number;
+}
+
+/**
+ * Spawn a subprocess with streaming callbacks and buffered results
+ */
+export async function spawn(options: SpawnOptions): Promise<SpawnResult> {
+  const { cmd, args, env, input, timeout, onStdout, onStderr } = options;
+
+  const startTime = Date.now();
+  let stdoutBuffer = "";
+  let stderrBuffer = "";
+
+  return new Promise((resolve, reject) => {
+    // Spawn the child process
+    const child = nodeSpawn(cmd, args, {
+      env: env ? { ...process.env, ...env } : process.env,
+      stdio: ["pipe", "pipe", "pipe"],
+    });
+
+    // Set up timeout if specified
+    let timeoutId: NodeJS.Timeout | undefined;
+    let isTimedOut = false;
+
+    if (timeout) {
+      timeoutId = setTimeout(() => {
+        isTimedOut = true;
+        child.kill("SIGTERM");
+
+        // If SIGTERM doesn't work, use SIGKILL after 5 seconds
+        setTimeout(() => {
+          if (!child.killed) {
+            child.kill("SIGKILL");
+          }
+        }, 5000);
+      }, timeout);
+    }
+
+    // Handle stdout streaming
+    if (child.stdout) {
+      child.stdout.on("data", (data: Buffer) => {
+        const chunk = data.toString();
+        stdoutBuffer += chunk;
+        onStdout?.(chunk);
+      });
+    }
+
+    // Handle stderr streaming
+    if (child.stderr) {
+      child.stderr.on("data", (data: Buffer) => {
+        const chunk = data.toString();
+        stderrBuffer += chunk;
+        onStderr?.(chunk);
+      });
+    }
+
+    // Handle process completion
+    child.on("close", (exitCode) => {
+      const durationMs = Date.now() - startTime;
+
+      if (timeoutId) {
+        clearTimeout(timeoutId);
+      }
+
+      if (isTimedOut) {
+        reject(new Error(`Process timed out after ${timeout}ms`));
+        return;
+      }
+
+      resolve({
+        stdout: stdoutBuffer,
+        stderr: stderrBuffer,
+        exitCode: exitCode || 0,
+        durationMs,
+      });
+    });
+
+    // Handle process errors
+    child.on("error", (error) => {
+      const durationMs = Date.now() - startTime;
+
+      if (timeoutId) {
+        clearTimeout(timeoutId);
+      }
+
+      // Still return buffered output even on error
+      resolve({
+        stdout: stdoutBuffer,
+        stderr: stderrBuffer,
+        exitCode: 1,
+        durationMs,
+      });
+    });
+
+    // Send input if provided
+    if (input && child.stdin) {
+      child.stdin.write(input);
+      child.stdin.end();
+    }
+  });
+}