use crate::Error;
use libc::{self, c_char, c_void};
use std::ffi::{CStr, CString};
use std::path::Path;
use std::ptr;
pub(crate) unsafe fn from_cstr(ptr: *const c_char) -> String {
let cstr = CStr::from_ptr(ptr as *const _);
String::from_utf8_lossy(cstr.to_bytes()).into_owned()
}
pub(crate) unsafe fn raw_data(ptr: *const c_char, size: usize) -> Option<Vec<u8>> {
if ptr.is_null() {
None
} else {
let mut dst = vec![0; size];
ptr::copy_nonoverlapping(ptr as *const u8, dst.as_mut_ptr(), size);
Some(dst)
}
}
pub fn error_message(ptr: *const c_char) -> String {
unsafe {
let s = from_cstr(ptr);
libc::free(ptr as *mut c_void);
s
}
}
pub fn opt_bytes_to_ptr<T: AsRef<[u8]>>(opt: Option<T>) -> *const c_char {
match opt {
Some(v) => v.as_ref().as_ptr() as *const c_char,
None => ptr::null(),
}
}
pub(crate) fn to_cpath<P: AsRef<Path>>(path: P) -> Result<CString, Error> {
match CString::new(path.as_ref().to_string_lossy().as_bytes()) {
Ok(c) => Ok(c),
Err(e) => Err(Error::new(format!(
"Failed to convert path to CString: {}",
e,
))),
}
}
macro_rules! ffi_try {
( $($function:ident)::*() ) => {
ffi_try_impl!($($function)::*())
};
( $($function:ident)::*( $arg1:expr $(, $arg:expr)* $(,)? ) ) => {
ffi_try_impl!($($function)::*($arg1 $(, $arg)* ,))
};
}
macro_rules! ffi_try_impl {
( $($function:ident)::*( $($arg:expr,)*) ) => {{
let mut err: *mut ::libc::c_char = ::std::ptr::null_mut();
let result = $($function)::*($($arg,)* &mut err);
if !err.is_null() {
return Err(Error::new($crate::ffi_util::error_message(err)));
}
result
}};
}
pub trait CStrLike {
type Baked: std::ops::Deref<Target = CStr>;
type Error: std::fmt::Debug + std::fmt::Display;
fn bake(self) -> Result<Self::Baked, Self::Error>;
fn into_c_string(self) -> Result<CString, Self::Error>;
}
impl CStrLike for &str {
type Baked = CString;
type Error = std::ffi::NulError;
fn bake(self) -> Result<Self::Baked, Self::Error> {
CString::new(self)
}
fn into_c_string(self) -> Result<CString, Self::Error> {
CString::new(self)
}
}
impl CStrLike for &String {
type Baked = CString;
type Error = std::ffi::NulError;
fn bake(self) -> Result<Self::Baked, Self::Error> {
CString::new(self.as_bytes())
}
fn into_c_string(self) -> Result<CString, Self::Error> {
CString::new(self.as_bytes())
}
}
impl CStrLike for &CStr {
type Baked = Self;
type Error = std::convert::Infallible;
fn bake(self) -> Result<Self::Baked, Self::Error> {
Ok(self)
}
fn into_c_string(self) -> Result<CString, Self::Error> {
Ok(self.to_owned())
}
}
impl CStrLike for CString {
type Baked = CString;
type Error = std::convert::Infallible;
fn bake(self) -> Result<Self::Baked, Self::Error> {
Ok(self)
}
fn into_c_string(self) -> Result<CString, Self::Error> {
Ok(self)
}
}
impl<'a> CStrLike for &'a CString {
type Baked = &'a CStr;
type Error = std::convert::Infallible;
fn bake(self) -> Result<Self::Baked, Self::Error> {
Ok(self)
}
fn into_c_string(self) -> Result<CString, Self::Error> {
Ok(self.clone())
}
}
#[test]
fn test_c_str_like_bake() {
fn test<S: CStrLike>(value: S) -> Result<usize, S::Error> {
value
.bake()
.map(|value| unsafe { libc::strlen(value.as_ptr()) })
}
assert_eq!(Ok(3), test("foo")); assert_eq!(Ok(3), test(&String::from("foo"))); assert_eq!(Ok(3), test(CString::new("foo").unwrap().as_ref())); assert_eq!(Ok(3), test(&CString::new("foo").unwrap())); assert_eq!(Ok(3), test(CString::new("foo").unwrap()));
assert_eq!(3, test("foo\0bar").err().unwrap().nul_position());
}
#[test]
fn test_c_str_like_into() {
fn test<S: CStrLike>(value: S) -> Result<CString, S::Error> {
value.into_c_string()
}
let want = CString::new("foo").unwrap();
assert_eq!(Ok(want.clone()), test("foo")); assert_eq!(Ok(want.clone()), test(&String::from("foo"))); assert_eq!(
Ok(want.clone()),
test(CString::new("foo").unwrap().as_ref())
); assert_eq!(Ok(want.clone()), test(&CString::new("foo").unwrap())); assert_eq!(Ok(want), test(CString::new("foo").unwrap()));
assert_eq!(3, test("foo\0bar").err().unwrap().nul_position());
}