utils.rs

use proc_macro2::Span;
use proc_macro_crate::crate_name;
use syn::{Ident, ItemFn};

/// Determines if this block of code was [generated by near_bindgen].
/// Heuristic used is to check for #[no_mangle].
/// TODO: How to make this 100% safe. Discuss with near-sdk team
///
/// [generated by near_bindgen]: https://github.com/near/near-sdk-rs/issues/722
pub(crate) fn is_near_bindgen_wrapped_or_marshall(item: &ItemFn) -> bool {
    let pattern1 = "(target_arch = \"wasm32\")";
    let pattern2 = "(not(target_arch = \"wasm32\"))";
    item.attrs.iter().any(|attr| {
        let seq = attr.tokens.to_string();
        seq == pattern1 || seq == pattern2
    })
}

/// Returns an identifier for the name of the crate which is imported by plugin users.
pub(crate) fn cratename() -> Ident {
    Ident::new(
        &crate_name("near-plugins").unwrap_or_else(|_| "near_plugins".to_string()),
        Span::call_site(),
    )
}

/// Injects extra code into a function.
pub(crate) fn add_extra_code_to_fn(
    fn_code: &ItemFn,
    extra_code: proc_macro2::TokenStream,
) -> proc_macro::TokenStream {
    let ItemFn {
        attrs,
        vis,
        sig,
        block,
    } = fn_code;
    let stmts = &block.stmts;

    // https://stackoverflow.com/a/66851407
    quote::quote! {
        #(#attrs)* #vis #sig {
            #extra_code
            #(#stmts)*
        }
    }
    .into()
}