freenet-macros 0.3.0

use quote::{quote, quote_spanned};
use syn::punctuated::Punctuated;
use syn::spanned::Spanned;
use syn::{ItemImpl, Meta, Token};

pub(crate) mod common;
mod contract_impl;
mod delegate_impl;

struct AttributeArgs {
    args: Punctuated<Meta, Token![,]>,
}

impl syn::parse::Parse for AttributeArgs {
    fn parse(input: syn::parse::ParseStream) -> syn::Result<Self> {
        let mut args = Punctuated::new();
        let mut punctuated;
        let mut count = 0;
        while !input.is_empty() {
            punctuated = input.parse::<Token![,]>().ok().is_some();
            if count > 0 && !punctuated {
                return Err(syn::Error::new(
                    input.span(),
                    "arguments must be comma separated",
                ));
            }
            let meta = input.parse::<Meta>()?;
            args.push(meta);
            count += 1;
        }
        Ok(AttributeArgs { args })
    }
}

enum ContractType {
    Raw,
    Typed,
    Composable,
}

/// Generate the necessary code for the WASM runtime to interact with your contract ergonomically and safely.
#[proc_macro_attribute]
pub fn contract(
    args: proc_macro::TokenStream,
    input: proc_macro::TokenStream,
) -> proc_macro::TokenStream {
    let args = syn::parse_macro_input!(args as AttributeArgs);
    let input = syn::parse_macro_input!(input as ItemImpl);
    let Some((_, path, _)) = &input.trait_ else {
        return proc_macro::TokenStream::from(quote_spanned! {
            input.span() =>
            compile_error!("only allowed for traits");
        });
    };
    match path.segments.last() {
        Some(segment) => {
            let c_type = match segment.ident.to_string().as_str() {
                "ContractInterface" => ContractType::Raw,
                "TypedContract" => ContractType::Typed,
                "ContractComponent" => ContractType::Composable,
                _ => {
                    return proc_macro::TokenStream::from(quote_spanned! {
                        segment.ident.span() =>
                        compile_error!("trait not supported for contract interaction");
                    })
                }
            };
            contract_impl::contract_ffi_impl(&input, &args, c_type)
        }
        None => proc_macro::TokenStream::from(quote_spanned! {
            path.span() =>
            compile_error!("missing trait identifier");
        }),
    }
}

/// Generate the necessary code for the WASM runtime to interact with your delegate ergonomically and safely.
///
/// # Declaring a manifest
///
/// A delegate that wants lifecycle events or node-enforced capabilities
/// declares them, and the macro embeds a manifest in the WASM
/// (see `freenet_stdlib::prelude::DelegateManifest`):
///
/// ```ignore
/// #[delegate(manifest(lifecycle = [Installed, NodeStarted], capabilities = [Background]))]
/// impl DelegateInterface for MyDelegate { /* ... */ }
/// ```
///
/// Without `manifest(...)` nothing is embedded and the delegate behaves as
/// delegates always have. Adding one changes the WASM, and so the delegate key.
///
/// Listing any lifecycle kind requires `capabilities = [Background]`. Only one
/// manifest per crate: the section is per WASM module. Custom sections must
/// survive any post-processing of the module (`wasm-opt --strip-*`,
/// `wasm-strip` remove them); a missing section means "no manifest", silently.
#[proc_macro_attribute]
pub fn delegate(
    args: proc_macro::TokenStream,
    input: proc_macro::TokenStream,
) -> proc_macro::TokenStream {
    let args = syn::parse_macro_input!(args as AttributeArgs);
    let input = syn::parse_macro_input!(input as ItemImpl);
    let manifest = match delegate_impl::parse_manifest_args(&args.args) {
        Ok(m) => m,
        Err(err) => return proc_macro::TokenStream::from(err.to_compile_error()),
    };
    let mut output = delegate_impl::ffi_impl_wrap(&input);
    if let Some(manifest) = manifest {
        output.extend(delegate_impl::manifest_section(&input, &manifest));
    }
    // println!("{}", quote!(#input));
    // println!("{output}");
    proc_macro::TokenStream::from(quote! {
        #input
        #output
    })
}