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#![allow(non_snake_case)]
use std::error;
use std::fmt;
use std::ptr;
mod c {
use std::ffi::c_void;
use std::os::raw::c_ulong;
pub type DWORD = c_ulong;
pub type HANDLE = LPVOID;
pub type LPVOID = *mut c_void;
pub type HINSTANCE = HANDLE;
pub type HMODULE = HINSTANCE;
pub type WCHAR = u16;
pub type LPCWSTR = *const WCHAR;
pub type LPWSTR = *mut WCHAR;
pub const FACILITY_NT_BIT: DWORD = 0x1000_0000;
pub const FORMAT_MESSAGE_FROM_HMODULE: DWORD = 0x00000800;
pub const FORMAT_MESSAGE_FROM_SYSTEM: DWORD = 0x00001000;
pub const FORMAT_MESSAGE_IGNORE_INSERTS: DWORD = 0x00000200;
extern "system" {
pub fn GetLastError() -> DWORD;
pub fn GetModuleHandleW(lpModuleName: LPCWSTR) -> HMODULE;
pub fn FormatMessageW(
flags: DWORD,
lpSrc: LPVOID,
msgId: DWORD,
langId: DWORD,
buf: LPWSTR,
nsize: DWORD,
args: *const c_void,
) -> DWORD;
}
}
macro_rules! last_ident {
($i:ident) => {
stringify!($i)
};
($start:ident, $($cont:ident),+) => {
last_ident!($($cont),+)
};
}
macro_rules! os_call {
($($path:ident)::+ ($($args:expr),*), $success:expr) => {
let result = unsafe{ $($path)::+ ($($args),+) };
if !($success)(result) {
let name = last_ident!($($path),+);
let err_code = $crate::win::errno();
Err($crate::win::OsError{
function: name,
error_code: err_code as u32,
message: $crate::win::error_string(err_code)
})?;
}
};
}
#[derive(Debug)]
pub struct OsError {
pub function: &'static str,
pub error_code: u32,
pub message: String,
}
impl fmt::Display for OsError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "{:?}", self)
}
}
impl error::Error for OsError {
fn source(&self) -> Option<&(dyn error::Error + 'static)> {
None
}
}
pub fn errno() -> i32 {
unsafe { c::GetLastError() as i32 }
}
/// Gets a detailed string description for the given error number.
pub fn error_string(mut errnum: i32) -> String {
// This value is calculated from the macro
// MAKELANGID(LANG_SYSTEM_DEFAULT, SUBLANG_SYS_DEFAULT)
let langId = 0x0800 as c::DWORD;
let mut buf = [0 as c::WCHAR; 2048];
unsafe {
let mut module = ptr::null_mut();
let mut flags = 0;
// NTSTATUS errors may be encoded as HRESULT, which may returned from
// GetLastError. For more information about Windows error codes, see
// `[MS-ERREF]`: https://msdn.microsoft.com/en-us/library/cc231198.aspx
if (errnum & c::FACILITY_NT_BIT as i32) != 0 {
// format according to https://support.microsoft.com/en-us/help/259693
const NTDLL_DLL: &[u16] = &[
'N' as _, 'T' as _, 'D' as _, 'L' as _, 'L' as _, '.' as _, 'D' as _, 'L' as _,
'L' as _, 0,
];
module = c::GetModuleHandleW(NTDLL_DLL.as_ptr());
if module != ptr::null_mut() {
errnum ^= c::FACILITY_NT_BIT as i32;
flags = c::FORMAT_MESSAGE_FROM_HMODULE;
}
}
let res = c::FormatMessageW(
flags | c::FORMAT_MESSAGE_FROM_SYSTEM | c::FORMAT_MESSAGE_IGNORE_INSERTS,
module,
errnum as c::DWORD,
langId,
buf.as_mut_ptr(),
buf.len() as c::DWORD,
ptr::null(),
) as usize;
if res == 0 {
// Sometimes FormatMessageW can fail e.g., system doesn't like langId,
let fm_err = errno();
return format!(
"OS Error {} (FormatMessageW() returned error {})",
errnum, fm_err
);
}
match String::from_utf16(&buf[..res]) {
Ok(mut msg) => {
// Trim trailing CRLF inserted by FormatMessageW
let len = msg.trim_end().len();
msg.truncate(len);
msg
}
Err(..) => format!(
"OS Error {} (FormatMessageW() returned \
invalid UTF-16)",
errnum
),
}
}
}
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