1 files changed, 65 insertions, 0 deletions
diff --git a/vendor/cstr/src/lib.rs b/vendor/cstr/src/lib.rs
new file mode 100644
index 000000000..d78eaa1b2
--- /dev/null
+++ b/vendor/cstr/src/lib.rs
@@ -0,0 +1,65 @@
+//! A macro for getting `&'static CStr` from literal or identifier.
+//!
+//! This macro checks whether the given literal is valid for `CStr`
+//! at compile time, and returns a static reference of `CStr`.
+//!
+//! This macro can be used to to initialize constants on Rust 1.46 and above.
+//!
+//! ## Example
+//!
+//! ```
+//! use cstr::cstr;
+//! use std::ffi::CStr;
+//!
+//! let test = cstr!(b"hello\xff");
+//! assert_eq!(test, CStr::from_bytes_with_nul(b"hello\xff\0").unwrap());
+//! let test = cstr!("hello");
+//! assert_eq!(test, CStr::from_bytes_with_nul(b"hello\0").unwrap());
+//! let test = cstr!(hello);
+//! assert_eq!(test, CStr::from_bytes_with_nul(b"hello\0").unwrap());
+//! ```
+
+// While this isn't necessary when using Cargo >= 1.42, omitting it actually requires path-less
+// `--extern proc_macro` to be passed to `rustc` when building this crate. Some tools may not do
+// this correctly. So it's added as a precaution.
+extern crate proc_macro;
+
+use crate::parse::parse_input;
+use proc_macro::TokenStream as RawTokenStream;
+use proc_macro2::{Literal, Span, TokenStream};
+use quote::{quote, quote_spanned};
+use std::ffi::CString;
+
+mod parse;
+
+struct Error(Span, &'static str);
+
+#[proc_macro]
+pub fn cstr(input: RawTokenStream) -> RawTokenStream {
+    let tokens = match build_byte_str(input.into()) {
+        // We can't use `&*ptr` to convert the raw pointer to reference, because as of Rust 1.46,
+        // dereferencing raw pointer in constants is unstable.
+        // This is being tracked in https://github.com/rust-lang/rust/issues/51911
+        // So we explicitly disable the clippy lint for this expression.
+        Ok(s) => quote!(unsafe {
+            #[allow(clippy::transmute_ptr_to_ref)]
+            ::std::mem::transmute::<_, &::std::ffi::CStr>(
+                #s as *const [u8] as *const ::std::ffi::CStr
+            )
+        }),
+        Err(Error(span, msg)) => quote_spanned!(span => compile_error!(#msg)),
+    };
+    tokens.into()
+}
+
+fn build_byte_str(input: TokenStream) -> Result<Literal, Error> {
+    let (bytes, span) = parse_input(input)?;
+    match CString::new(bytes) {
+        Ok(s) => {
+            let mut lit = Literal::byte_string(s.as_bytes_with_nul());
+            lit.set_span(span);
+            Ok(lit)
+        }
+        Err(_) => Err(Error(span, "nul byte found in the literal")),
+    }
+}