Use Inko for getting the errno location

We can just read this using the C FFI instead of going through an extra
Rust function call.

Changelog: changed

rt/src/runtime/general.rs

@@ -2,28 +2,6 @@ use crate::mem::{header_of, ClassPointer};
 use crate::process::ProcessPointer;
 use crate::runtime::process::panic;
 use std::alloc::handle_alloc_error;
-use std::io::Error;
-
-// Taken from Rust's standard library, with some removals of platforms we don't
-// support.
-extern "C" {
-    #[cfg_attr(any(target_os = "linux",), link_name = "__errno_location")]
-    #[cfg_attr(
-        any(target_os = "netbsd", target_os = "android",),
-        link_name = "__errno"
-    )]
-    #[cfg_attr(
-        any(
-            target_os = "macos",
-            target_os = "ios",
-            target_os = "tvos",
-            target_os = "freebsd",
-            target_os = "watchos"
-        ),
-        link_name = "__error"
-    )]
-    fn errno_location() -> *mut i32;
-}
 
 #[no_mangle]
 pub unsafe extern "system" fn inko_reference_count_error(
@@ -45,13 +23,3 @@ pub unsafe extern "system" fn inko_reference_count_error(
 pub unsafe extern "system" fn inko_alloc_error(class: ClassPointer) -> ! {
     handle_alloc_error(class.instance_layout());
 }
-
-#[no_mangle]
-pub unsafe extern "system" fn inko_last_error() -> i64 {
-    Error::last_os_error().raw_os_error().unwrap_or(-1) as i64
-}
-
-#[no_mangle]
-pub unsafe extern "system" fn inko_reset_error() {
-    *errno_location() = 0;
-}

std/src/std/io.inko

@@ -30,10 +30,6 @@ let INVALID_DATA = -2
 # The error code used when encountering an unexpected end of the input.
 let UNEXPECTED_EOF = -3
 
-fn extern inko_last_error -> Int
-
-fn extern inko_reset_error
-
 fn extern inko_process_start_blocking(process: Pointer[UInt8])
 
 fn extern inko_process_stop_blocking(process: Pointer[UInt8])
@@ -91,7 +87,7 @@ fn pub start_blocking {
 # rescheduled the current process may run on a different OS thread and thus read
 # a different state.
 fn pub stop_blocking -> Int {
-  let err = inko_last_error
+  let err = libc.errno_location.0 as Int
 
   # If the operation took too long, this reschedules the current process. This
   # means that any global state read after this point may not be from the same
@@ -101,7 +97,7 @@ fn pub stop_blocking -> Int {
 }
 
 fn reset_os_error {
-  inko_reset_error
+  libc.errno_location.0 = 0 as Int32
 }
 
 # An error type for I/O operations.
@@ -279,7 +275,7 @@ class pub enum Error {
 
   # Returns the last OS error produced by the current OS thread.
   fn pub static last_os_error -> Error {
-    from_os_error(inko_last_error)
+    from_os_error(libc.errno_location.0 as Int)
   }
 }
 

std/src/std/libc.inko

@@ -216,3 +216,7 @@ fn dirent_name(pointer: Pointer[sys.Dirent]) -> Pointer[UInt8] {
 fn pipes -> Result[(Int32, Int32), Error] {
   sys.pipes
 }
+
+fn errno_location -> Pointer[Int32] {
+  sys.errno_location
+}

std/src/std/libc/freebsd.inko

@@ -163,6 +163,8 @@ fn extern copy_file_range(
 
 fn extern pipe2(pipes: Pointer[Pipes], flags: Int32) -> Int32
 
+fn extern __error -> Pointer[Int32]
+
 fn flush(fd: Int32) -> Int32 {
   fsync(fd)
 }
@@ -184,3 +186,7 @@ fn pipes -> Result[(Int32, Int32), Error] {
 
   Result.Ok((pipes.reader, pipes.writer))
 }
+
+fn errno_location -> Pointer[Int32] {
+  __error
+}

std/src/std/libc/linux.inko

@@ -228,6 +228,8 @@ fn extern copy_file_range(
 
 fn extern pipe2(pipes: Pointer[Pipes], flags: Int32) -> Int32
 
+fn extern __errno_location -> Pointer[Int32]
+
 fn flush(fd: Int32) -> Int32 {
   fsync(fd)
 }
@@ -272,3 +274,7 @@ fn pipes -> Result[(Int32, Int32), Error] {
 
   Result.Ok((pipes.reader, pipes.writer))
 }
+
+fn errno_location -> Pointer[Int32] {
+  __errno_location
+}

std/src/std/libc/mac.inko

@@ -156,6 +156,8 @@ fn extern fcopyfile(
 
 fn extern pipe(pipes: Pointer[Pipes]) -> Int32
 
+fn extern __error -> Pointer[Int32]
+
 fn fstat(fd: Int32, buf: Pointer[StatBuf]) -> Int32 {
   sys.fstat(fd, buf)
 }
@@ -223,3 +225,7 @@ fn pipes -> Result[(Int32, Int32), Error] {
 
   Result.Ok((pipes.reader, pipes.writer))
 }
+
+fn errno_location -> Pointer[Int32] {
+  __error
+}