diff options
author | Justus Winter <justus@sequoia-pgp.org> | 2019-02-04 15:12:22 +0100 |
---|---|---|
committer | Justus Winter <justus@sequoia-pgp.org> | 2019-02-05 17:54:20 +0100 |
commit | 12f617efc3e99d6bb2c5b36ba2547463c6031555 (patch) | |
tree | ff1b0eda0d9a9baccd379275baa12828250d5125 /ffi-macros/src/lib.rs | |
parent | caf3f3ae3d2645dbdc47101e05a88c306a2cb989 (diff) |
ffi-macros: Embed and display actual type in panics.
Diffstat (limited to 'ffi-macros/src/lib.rs')
-rw-r--r-- | ffi-macros/src/lib.rs | 27 |
1 files changed, 25 insertions, 2 deletions
diff --git a/ffi-macros/src/lib.rs b/ffi-macros/src/lib.rs index 131e1f45..d398e32d 100644 --- a/ffi-macros/src/lib.rs +++ b/ffi-macros/src/lib.rs @@ -282,6 +282,18 @@ fn derive_conversion_functions(mut st: syn::ItemStruct, // The value is a compile-time constant. let magic_value = hash_ident(&wrapper); + // To help during debugging, we store the name of the type. + const C_TYPE_NAME_LEN: usize = 32; + let c_type_name_type = syn::parse_quote!([u8; #C_TYPE_NAME_LEN]); + let mut c_type_name_padded = [0u8; C_TYPE_NAME_LEN]; + &mut c_type_name_padded[..::std::cmp::min(C_TYPE_NAME_LEN, + c_type_name.as_bytes().len())] + .copy_from_slice(c_type_name.as_bytes()); + let c_type_name_padded_literal = + syn::parse_str::<proc_macro2::TokenStream>( + &format!("{:?}", c_type_name_padded)) + .expect("parsing array failed"); + let ownership = proc_macro2::Ident::new(&format!("{}Ownership", wrapper), proc_macro2::Span::call_site()); @@ -315,6 +327,15 @@ fn derive_conversion_functions(mut st: syn::ItemStruct, ty: tag_type, } ); + fields.unnamed.push( + syn::Field { + attrs: vec![], + vis: syn::Visibility::Inherited, + ident: None, + colon_token: None, + ty: c_type_name_type, + } + ); }, _ => return syn::Error::new(argument_span, @@ -342,8 +363,9 @@ fn derive_conversion_functions(mut st: syn::ItemStruct, } else { panic!( "FFI contract violation: Wrong parameter type: \ - expected {}", + expected {}, got {}", #c_type_name, + String::from_utf8_lossy(&self.2), ); } } @@ -432,7 +454,8 @@ fn derive_conversion_functions(mut st: syn::ItemStruct, impl #wrapper { fn wrap(obj: #ownership) -> *mut #wrapper { - Box::into_raw(Box::new(#wrapper(obj, #magic_value))) + Box::into_raw(Box::new(#wrapper(obj, #magic_value, + #c_type_name_padded_literal))) } } |