From c54ff48ac3abb62a40eb1a438da8e3e7ef139797 Mon Sep 17 00:00:00 2001
From: Lexi Winter <lexi@le-fay.org>
Date: Sat, 28 Jun 2025 20:40:25 +0100
Subject: posix: add tempfile()

---
 nihil.posix/posix.process.cc | 102 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 102 insertions(+)
 create mode 100644 nihil.posix/posix.process.cc

(limited to 'nihil.posix/posix.process.cc')

diff --git a/nihil.posix/posix.process.cc b/nihil.posix/posix.process.cc
new file mode 100644
index 0000000..70e84b7
--- /dev/null
+++ b/nihil.posix/posix.process.cc
@@ -0,0 +1,102 @@
+/*
+ * This source code is released into the public domain.
+ */
+
+module;
+
+#include <cerrno>
+#include <cstring>
+#include <expected>
+#include <format>
+#include <optional>
+#include <system_error>
+#include <utility>
+
+#include <sys/types.h>
+#include <sys/wait.h>
+
+module nihil.posix;
+
+import nihil.error;
+
+namespace nihil {
+
+auto wait_result::okay(this wait_result const &self) -> bool
+{
+	return self.status() == 0;
+}
+
+wait_result::operator bool(this wait_result const &self)
+{
+	return self.okay();
+}
+
+auto wait_result::status(this wait_result const &self) -> std::optional<int>
+{
+	if (WIFEXITED(self._status))
+		return WEXITSTATUS(self._status);
+	return {};
+}
+
+auto wait_result::signal(this wait_result const &self) -> std::optional<int>
+{
+	if (WIFSIGNALED(self._status))
+		return WTERMSIG(self._status);
+	return {};
+}
+
+wait_result::wait_result(int status)
+	: _status(status)
+{}
+
+process::process(::pid_t pid)
+	: m_pid(pid)
+{}
+
+process::~process() {
+	if (m_pid == -1)
+		return;
+
+	auto status = int{};
+	std::ignore = waitpid(m_pid, &status, WEXITED);
+}
+
+process::process(process &&other) noexcept
+	: m_pid(std::exchange(other.m_pid, -1))
+{
+}
+
+auto process::operator=(this process &self, process &&other) noexcept
+	-> process &
+{
+	if (&self != &other) {
+		self.m_pid = std::exchange(other.m_pid, -1);
+	}
+
+	return self;
+}
+
+// Get the child's process id.
+auto process::pid(this process const &self) noexcept -> ::pid_t
+{
+	return self.m_pid;
+}
+
+auto process::wait(this process &&self) -> std::expected<wait_result, error>
+{
+	auto status = int{};
+	auto ret = waitpid(self.m_pid, &status, WEXITED);
+	if (ret == -1)
+		return std::unexpected(error(std::errc(errno)));
+
+	return wait_result(status);
+}
+
+auto process::release(this process &&self) -> ::pid_t
+{
+	auto const ret = self.pid();
+	self.m_pid = -1;
+	return ret;
+}
+
+} // namespace nihil
-- 
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