feat: first impl

src/Child.php

@@ -0,0 +1,49 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Nih\CommandBuilder;
+
+final class Child
+{
+    /**
+     * @param resource $proc The process handle.
+     */
+    public function __construct(
+        public readonly ?ChildStdin $stdin,
+        public readonly ?ChildStdout $stdout,
+        public readonly ?ChildStderr $stderr,
+        public $proc,
+    ) {
+    }
+
+    public function id(): int
+    {
+        $status = proc_get_status($this->proc);
+        return $status['pid'];
+    }
+
+    public function output(): Output
+    {
+        $stdout = $this->stdout?->getContents();
+        $stderr = $this->stderr?->getContents();
+        $code = proc_close($this->proc);
+
+        return new Output($stdout, $stderr, $code);
+    }
+
+    public function status(): int
+    {
+        return proc_close($this->proc);
+    }
+
+    public function wait(): void
+    {
+        proc_close($this->proc);
+    }
+
+    public function kill(): bool
+    {
+        return proc_terminate($this->proc, 10);
+    }
+}