stackerror_impl/
lib.rs

1use proc_macro::TokenStream;
2use quote::quote;
3use syn::{parse_macro_input, DeriveInput};
4
5#[proc_macro_attribute]
6pub fn derive_stack_error(_attr: TokenStream, item: TokenStream) -> TokenStream {
7    let input = parse_macro_input!(item as DeriveInput);
8    let name = &input.ident;
9    let first_field_type = if let syn::Data::Struct(data) = &input.data {
10        if let Some(field) = data.fields.iter().next() {
11            &field.ty
12        } else {
13            panic!("Expected at least one field");
14        }
15    } else {
16        panic!("Expected a struct");
17    };
18
19    let expanded = quote! {
20        #input
21
22        impl #name {
23            pub fn new() -> Self {
24                Self(#first_field_type::new())
25            }
26
27            pub fn from_msg(error: impl std::fmt::Display + Send + Sync + 'static) -> Self {
28                Self(#first_field_type::from_msg(error))
29            }
30        }
31
32        impl ErrorStacks<ErrorCode> for #name {
33            fn err_code(&self) -> Option<&ErrorCode> {
34                self.0.err_code()
35            }
36
37            fn with_err_code(self, code: ErrorCode) -> Self {
38                Self(self.0.with_err_code(code))
39            }
40
41            fn with_no_err_code(self) -> Self {
42                Self(self.0.with_no_err_code())
43            }
44
45            fn err_uri(&self) -> Option<&str> {
46                self.0.err_uri()
47            }
48
49            fn with_err_uri(self, uri: String) -> Self {
50                Self(self.0.with_err_uri(uri))
51            }
52
53            fn with_no_err_uri(self) -> Self {
54                Self(self.0.with_no_err_uri())
55            }
56
57            fn with_err_msg(self, error: impl std::fmt::Display + Send + Sync + 'static) -> Self {
58                Self(self.0.with_err_msg(error))
59            }
60
61            fn with_no_err_msg(self) -> Self {
62                Self(self.0.with_no_err_msg())
63            }
64
65            fn stack_err(self) -> Self {
66               Self(self.0.stack_err())
67            }
68
69            fn stack_err_msg(self, error: impl std::fmt::Display + Send + Sync + 'static) -> Self {
70               Self(self.0.stack_err_msg(error))
71            }
72        }
73
74        impl std::fmt::Display for #name {
75            fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
76                std::fmt::Display::fmt(&self.0, f)
77            }
78        }
79
80        impl std::fmt::Debug for #name {
81            fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
82                std::fmt::Debug::fmt(&self.0, f)
83            }
84        }
85
86        impl std::error::Error for #name {
87            fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
88                self.0.source()
89            }
90        }
91
92        impl<E> From<E> for #name
93        where
94            StackError: From<E>,
95        {
96            fn from(err: E) -> Self {
97                Self(StackError::from(err))
98            }
99        }
100    };
101
102    TokenStream::from(expanded)
103}
stackerror_impl/lib.rs

stackerror_impl/
lib.rs
