remotia_buffer_utils_macros/
lib.rs

1extern crate proc_macro;
2
3use core::panic;
4
5use proc_macro::TokenStream;
6use proc_macro2::{Span, TokenTree};
7use quote::{quote, ToTokens};
8use syn::{parse_macro_input, Ident, ItemStruct};
9
10#[proc_macro_attribute]
11pub fn buffers_map(attr: TokenStream, input: TokenStream) -> TokenStream {
12    // Parse the input tokens into a syntax tree
13    let input = parse_macro_input!(input as ItemStruct);
14
15    // Extract the field name from the macro arguments
16    let field_name = Ident::new(&attr.to_string(), Span::call_site());
17
18    // Get the name of the struct
19    let name = input.ident.clone();
20
21    // Find the field in the struct by its name
22    let field = input
23        .fields
24        .iter()
25        .find(|f| f.ident.as_ref() == Some(&field_name))
26        .unwrap();
27
28    // Extract the type of the field
29    let field_type_tokens = &field
30        .ty
31        .to_token_stream()
32        .into_iter()
33        .collect::<Vec<TokenTree>>();
34
35    let ty = field_type_tokens
36        .get(0)
37        .expect("Unable to read field first token");
38
39    if ty.to_string() != "BuffersMap" {
40        panic!("The field should be of type BuffersMap");
41    }
42
43    let key_type_name = Ident::new(&field_type_tokens
44        .get(2)
45        .expect("Unable to read key type")
46        .to_string(), Span::call_site());
47
48    // Generate the implementation of PullableFrameProperties
49    let expanded = quote! {
50        #input
51
52        impl remotia::traits::PullableFrameProperties<#key_type_name, BytesMut> for #name {
53            fn push(&mut self, key: #key_type_name, value: BytesMut) {
54                self.#field_name.insert(key, value);
55            }
56
57            fn pull(&mut self, key: &#key_type_name) -> Option<BytesMut> {
58                self.#field_name.remove(key)
59            }
60        }
61    };
62
63    // Hand the output tokens back to the compiler
64    TokenStream::from(expanded)
65}
remotia_buffer_utils_macros/lib.rs

remotia_buffer_utils_macros/
lib.rs
