fluvio-protocol-derive 0.50.1

Procedure macro to encode/decode fluvio protocol
Documentation 
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use quote::ToTokens;
use syn::{Attribute, Lit, Meta, NestedMeta, Result};

#[derive(Debug, Default)]
pub struct ContainerAttributes {
    pub varint: bool,
    pub default: bool,

    pub encode_discriminant: bool,
    pub api_min_version: u16,
    pub api_max_version: Option<u16>,
    pub api_key: Option<u8>,
    pub response: Option<String>,
    pub repr_type_name: Option<String>,
    pub trace: bool,
}

impl ContainerAttributes {
    pub fn from_ast(attributes: &[Attribute]) -> Result<ContainerAttributes> {
        let mut cont_attr = ContainerAttributes::default();
        // Find all supported container level attributes in one go
        for attribute in attributes {
            if attribute.path.is_ident("varint") {
                cont_attr.varint = true;
            } else if attribute.path.is_ident("fluvio") {
                if let Ok(Meta::List(list)) = attribute.parse_meta() {
                    for kf_attr in list.nested {
                        if let NestedMeta::Meta(Meta::NameValue(name_value)) = kf_attr {
                            if name_value.path.is_ident("api_min_version") {
                                if let Lit::Int(lit_int) = &name_value.lit {
                                    cont_attr.api_min_version = lit_int.base10_parse::<u16>()?;
                                }
                            } else if name_value.path.is_ident("api_max_version") {
                                if let Lit::Int(lit_int) = &name_value.lit {
                                    cont_attr.api_max_version =
                                        Some(lit_int.base10_parse::<u16>()?);
                                }
                            } else if name_value.path.is_ident("api_key") {
                                if let Lit::Int(lit_int) = &name_value.lit {
                                    cont_attr.api_key = Some(lit_int.base10_parse::<u8>()?);
                                }
                            } else if name_value.path.is_ident("response") {
                                if let Lit::Str(lit_str) = &name_value.lit {
                                    cont_attr.response = Some(lit_str.value());
                                }
                            } else {
                                tracing::warn!(
                                    "#[fluvio({})] does nothing on the container.",
                                    name_value.to_token_stream().to_string()
                                )
                            }
                        } else if let NestedMeta::Meta(Meta::Path(path)) = kf_attr {
                            if path.is_ident("default") {
                                cont_attr.default = true;
                            } else if path.is_ident("trace") {
                                cont_attr.trace = true;
                            } else if path.is_ident("encode_discriminant") {
                                cont_attr.encode_discriminant = true;
                            } else {
                                tracing::warn!(
                                    "#[fluvio({})] does nothing on the container.",
                                    path.to_token_stream().to_string()
                                )
                            }
                        }
                    }
                }
            } else if attribute.path.is_ident("repr") {
                if let Ok(Meta::List(list)) = attribute.parse_meta() {
                    for repr_attr in list.nested {
                        if let NestedMeta::Meta(Meta::Path(path)) = repr_attr {
                            if let Some(int_type) = path.get_ident() {
                                cont_attr.repr_type_name = Some(int_type.to_string());
                            }
                        }
                    }
                }
            }
        }
        Ok(cont_attr)
    }
}