liblinux++

commit d9b07a955ad27b4143c3f34b18b1130957718d50
parent 6f3496ae521b5cb620b09de33f5c13030a02a417
Author: Henry Wilson <henry@henryandlizzy.uk>
Date:   Thu,  8 Jan 2026 21:28:37 +0000

noexcept more things

Diffstat:
M
linux.hpp
 | 
48
++++++++++++++++++++++++++++++------------------
M
ls.cpp
 | 
11
+----------

2 files changed, 31 insertions(+), 28 deletions(-)
diff --git a/linux.hpp b/linux.hpp
@@ -49,13 +49,13 @@ template <typename T>
 struct span
 {
 	span() = default;
-	inline span(T* p, size_t n)
+	inline span(T* p, size_t n) noexcept
 	: ptr{p}
 	, len{n}
 	{}
 
 	template <size_t N>
-	inline span(T (&arr)[N])
+	inline span(T (&arr)[N]) noexcept
 	: span{arr, N}
 	{}
 
@@ -83,8 +83,8 @@ private:
 struct file
 {
 	constexpr file() = default;
-	constexpr explicit file(int n) : num{n} {}
-	constexpr operator bool() const { return num >= 0; }
+	constexpr explicit file(int n) noexcept : num{n} {}
+	constexpr operator bool() const noexcept { return num >= 0; }
 	int num = -1;
 };
 
@@ -98,8 +98,8 @@ enum class errno_t : int16_t;
 template <typename T>
 struct [[nodiscard]] syscall_result
 {
-	explicit operator bool() const { return val >= 0; }
-	T operator*() const
+	explicit operator bool() const noexcept { return val >= 0; }
+	T operator*() const noexcept
 	{
 		assert(*this);
 		if constexpr (__is_pointer(T))
@@ -107,7 +107,7 @@ struct [[nodiscard]] syscall_result
 		else
 			return static_cast<T>(val);
 	}
-	errno_t err() const
+	errno_t err() const noexcept
 	{
 		assert(not *this);
 		return static_cast<errno_t>(val);
@@ -118,17 +118,29 @@ private:
 
 struct c_str
 {
-	constexpr c_str(char const *p)
+	constexpr c_str(char const *p) noexcept
 	: str{p}
 	{}
 
 	template <size_t N>
-	constexpr c_str(char const (&arr)[N])
+	constexpr c_str(char const (&arr)[N]) noexcept
 	: str{arr}
 	{
 		static_assert(N > 0);
 		static_assert(arr[N-1] == '\0');
 	}
+	size_t length() const noexcept
+	{
+		if (not str)
+			return 0;
+
+		char const* p = str;
+		while (*p)
+			++p;
+
+		return p - str;
+	}
+
 private:
 	[[maybe_unused]] char const* str;
 };
@@ -187,11 +199,11 @@ enum class unlink_flags : int
 	REMOVEDIR = 0x200,
 };
 
-extern syscall_result<void> unlinkat(file dir, c_str path, unlink_flags flags);
+extern syscall_result<void> unlinkat(file dir, c_str path, unlink_flags flags) noexcept;
 
-extern syscall_result<void> execve(c_str path, char *const /*_Nullable*/ argv[], char *const /*_Nullable*/ envp[]);
+extern syscall_result<void> execve(c_str path, char *const /*_Nullable*/ argv[], char *const /*_Nullable*/ envp[]) noexcept;
 
-extern syscall_result<file> socket(int domain, int type, int protocol);
+extern syscall_result<file> socket(int domain, int type, int protocol) noexcept;
 
 struct addr_ref
 {
@@ -200,7 +212,7 @@ struct addr_ref
 
 struct in_addr
 {
-	in_addr(uint16_t port, uint32_t ipv4)
+	in_addr(uint16_t port, uint32_t ipv4) noexcept
 	: family{2}
 	, data{
 		uint8_t((port & 0xFF00) >> 8),
@@ -212,13 +224,13 @@ struct in_addr
 	}
 	{}
 
-	operator addr_ref() const { return {.fat_ptr = {(char const*)this, sizeof(*this)}}; }
+	operator addr_ref() const noexcept { return {.fat_ptr = {(char const*)this, sizeof(*this)}}; }
 private:
 	[[maybe_unused]] uint16_t family;
 	[[maybe_unused]] uint8_t data[14];
 };
 
-extern syscall_result<void> bind(file socket, addr_ref addr);
-extern syscall_result<void> listen(file socket, int backlog);
-extern syscall_result<file> accept(file socket, void* addr_buf, socklen_t* addr_len);
-extern syscall_result<file> dup(file oldfd, file newfd, int flags = 0);
+extern syscall_result<void> bind(file socket, addr_ref addr) noexcept;
+extern syscall_result<void> listen(file socket, int backlog) noexcept;
+extern syscall_result<file> accept(file socket, void* addr_buf, socklen_t* addr_len) noexcept;
+extern syscall_result<file> dup(file oldfd, file newfd, int flags = 0) noexcept;
diff --git a/ls.cpp b/ls.cpp
@@ -1,14 +1,5 @@
 #include "linux.hpp"
 
-static size_t strlen(char const* p)
-{
-	char const* const begin = p;
-	while (*p)
-		++p;
-
-	return p - begin;
-}
-
 int main()
 {
 	auto dir = openat(AT_FDCWD, ".", O_RDONLY, 0);
@@ -29,7 +20,7 @@ int main()
 		{
 			auto e = reinterpret_cast<linux_dirent64*>(buf + i);
 			char* const name = buf + i + sizeof(linux_dirent64);
-			size_t len = strlen(name);
+			size_t len = c_str{name}.length();
 			name[len++] = '\n';
 			ios[n_io++] = span<char const>{name, len};
 			i += e->d_reclen;