1 files changed, 220 insertions, 0 deletions
diff --git a/nihil.posix/posix.fd.cc b/nihil.posix/posix.fd.cc
new file mode 100644
index 0000000..6d5e54f
--- /dev/null
+++ b/nihil.posix/posix.fd.cc
@@ -0,0 +1,220 @@
+/*
+ * This source code is released into the public domain.
+ */
+
+module;
+
+#include <fcntl.h>
+#include <unistd.h>
+
+#include <coroutine>
+#include <expected>
+#include <format>
+#include <stdexcept>
+#include <system_error>
+
+module nihil.posix;
+
+import nihil.error;
+import nihil.monad;
+
+namespace nihil {
+
+fd::fd() noexcept = default;
+
+fd::fd(int fileno) noexcept
+	: m_fileno(fileno)
+{
+}
+
+fd::~fd()
+{
+	if (*this)
+		std::ignore = this->close();
+}
+
+fd::fd(fd &&other) noexcept
+	: m_fileno(std::exchange(other.m_fileno, invalid_fileno))
+{
+}
+
+auto fd::operator=(this fd &self, fd &&other) noexcept -> fd &
+{
+	if (&self != &other)
+		self.m_fileno = std::exchange(other.m_fileno, invalid_fileno);
+	return self;
+}
+
+fd::operator bool(this fd const &self) noexcept
+{
+	return self.m_fileno != invalid_fileno;
+}
+
+auto fd::close(this fd &self) -> std::expected<void, error>
+{
+	auto const ret = ::close(self.get());
+	self.m_fileno = invalid_fileno;
+
+	if (ret == 0)
+		return {};
+
+	return std::unexpected(error(std::errc(errno)));
+}
+
+auto fd::get(this fd const &self) -> int
+{
+	if (self)
+		return self.m_fileno;
+	throw std::logic_error("Attempt to call get() on invalid fd");
+}
+
+auto fd::release(this fd &&self) -> int
+{
+	if (self)
+		return std::exchange(self.m_fileno, invalid_fileno);
+	throw std::logic_error("Attempt to release an invalid fd");
+}
+
+auto dup(fd const &self) -> std::expected<fd, error>
+{
+	auto const newfd = ::dup(self.get());
+	if (newfd != -1)
+		return newfd;
+
+	return std::unexpected(error(std::errc(errno)));
+}
+
+auto dup(fd const &self, int newfd) -> std::expected<fd, error>
+{
+	auto const ret = ::dup2(self.get(), newfd);
+	if (ret != -1)
+		return newfd;
+
+	return std::unexpected(error(std::errc(errno)));
+}
+
+auto raw_dup(fd const &self) -> std::expected<int, error>
+{
+	auto const newfd = ::dup(self.get());
+	if (newfd != -1)
+		return newfd;
+
+	return std::unexpected(error(std::errc(errno)));
+}
+
+auto raw_dup(fd const &self, int newfd) -> std::expected<int, error>
+{
+	auto const ret = ::dup2(self.get(), newfd);
+	if (ret != -1)
+		return newfd;
+
+	return std::unexpected(error(std::errc(errno)));
+}
+
+auto getflags(fd const &self) -> std::expected<int, error>
+{
+	auto const flags = ::fcntl(self.get(), F_GETFL);
+	if (flags != -1)
+		return flags;
+
+	return std::unexpected(error(std::errc(errno)));
+}
+
+auto replaceflags(fd &self, int newflags) -> std::expected<void, error>
+{
+	auto const ret = ::fcntl(self.get(), F_SETFL, newflags);
+	if (ret == 0)
+		return {};
+
+	return std::unexpected(error(std::errc(errno)));
+}
+
+auto setflags(fd &self, int newflags) -> std::expected<int, error>
+{
+	auto flags = co_await getflags(self);
+
+	flags |= newflags;
+	co_await replaceflags(self, flags);
+
+	co_return flags;
+}
+
+auto clearflags(fd &self, int clrflags) -> std::expected<int, error>
+{
+	auto flags = co_await getflags(self);
+
+	flags &= ~clrflags;
+	co_await replaceflags(self, flags);
+
+	co_return flags;
+}
+
+auto getfdflags(fd const &self) -> std::expected<int, error>
+{
+	auto const flags = ::fcntl(self.get(), F_GETFD);
+	if (flags != -1)
+		return flags;
+
+	return std::unexpected(error(std::errc(errno)));
+}
+
+auto replacefdflags(fd &self, int newflags) -> std::expected<void, error>
+{
+	auto const ret = ::fcntl(self.get(), F_SETFD, newflags);
+	if (ret != -1)
+		return {};
+
+	return std::unexpected(error(std::errc(errno)));
+}
+
+auto setfdflags(fd &self, int newflags) -> std::expected<int, error>
+{
+	auto flags = co_await getfdflags(self);
+
+	flags |= newflags;
+	co_await replacefdflags(self, flags);
+
+	co_return flags;
+}
+
+auto clearfdflags(fd &self, int clrflags) -> std::expected<int, error>
+{
+	auto flags = co_await getfdflags(self);
+
+	flags &= ~clrflags;
+	co_await replacefdflags(self, flags);
+
+	co_return flags;
+}
+
+auto pipe() -> std::expected<std::pair<fd, fd>, error>
+{
+	auto fds = std::array<int, 2>{};
+
+	if (auto const ret = ::pipe(fds.data()); ret != 0)
+		return std::unexpected(error(std::errc(errno)));
+
+	return {{fd(fds[0]), fd(fds[1])}};
+}
+
+auto fd::write(this fd &self, std::span<std::byte const> buffer)
+	-> std::expected<std::size_t, error>
+{
+	auto const ret = ::write(self.get(), buffer.data(), buffer.size());
+	if (ret >= 0)
+		return ret;
+
+	return std::unexpected(error(std::errc(errno)));
+}
+
+auto fd::read(this fd &self, std::span<std::byte> buffer)
+	-> std::expected<std::span<std::byte>, error>
+{
+	auto const ret = ::read(self.get(), buffer.data(), buffer.size());
+	if (ret >= 0)
+		return buffer.subspan(0, ret);
+
+	return std::unexpected(error(std::errc(errno)));
+}
+
+} // namespace nihil