use crate::ModelAttributes;
use proc_macro2::TokenStream;
use quote::quote;
pub(crate) fn generate_native_model_encode_downgrade_body(attrs: &ModelAttributes) -> TokenStream {
let native_model_from = attrs.from.clone();
let native_model_try_from = attrs.try_from.clone();
let model_from_or_try_from = if let Some(from) = native_model_from {
quote! {
#from::native_model_encode_downgrade_body(self.into(), version)
}
} else if let Some((try_from, error_try_from)) = native_model_try_from {
quote! {
let result = #try_from::native_model_encode_downgrade_body(
self.try_into()
.map_err(|e: #error_try_from| native_model::DowngradeError {
msg: format!("{}", e),
source: e.into(),
})?,
version,
)?;
Ok(result)
}
} else {
quote! {
Err(native_model::Error::DowngradeNotSupported {
from: version,
to: Self::native_model_version(),
})
}
};
let gen = quote! {
fn native_model_encode_downgrade_body(self, version: u32) -> native_model::Result<Vec<u8>> {
if version == Self::native_model_version() {
let result = self.native_model_encode_body()?;
Ok(result)
} else if version < Self::native_model_version() {
#model_from_or_try_from
} else {
Err(native_model::Error::DowngradeNotSupported {
from: version,
to: Self::native_model_version(),
})
}
}
};
gen
}