sui_analytics_indexer_derive/
lib.rs

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// Copyright (c) Mysten Labs, Inc.
// SPDX-License-Identifier: Apache-2.0

use proc_macro::TokenStream;
use quote::quote;
use syn::{parse_macro_input, Data, DeriveInput, Fields};

#[proc_macro_derive(SerializeParquet)]
pub fn schema_derive(input: TokenStream) -> TokenStream {
    let input = parse_macro_input!(input as DeriveInput);
    let struct_name = &input.ident;
    let (schema, getter_implementation) = match &input.data {
        Data::Struct(data_struct) => match &data_struct.fields {
            Fields::Named(fields) => {
                let (schema_iter, getter_iter): (Vec<_>, Vec<_>) = fields
                    .named
                    .iter()
                    .enumerate()
                    .map(|(idx, field)| {
                        let field_name = field.ident.as_ref().unwrap().to_string();
                        (
                            format!("\"{}\".to_string()", field_name),
                            format!(
                                "if idx == {} {{ return self.{}.clone().into(); }}",
                                idx, field_name
                            ),
                        )
                    })
                    .unzip();
                (schema_iter.join(", "), getter_iter.join("\n"))
            }
            _ => panic!("not supported struct for parquet serialization"),
        },
        _ => panic!("not supported struct for parquet serialization"),
    };
    let schema_tokens: proc_macro2::TokenStream = schema.parse().unwrap();
    let getter_implementation_tokens: proc_macro2::TokenStream =
        getter_implementation.parse().unwrap();
    quote! {
        impl ParquetSchema for #struct_name {
            fn schema() -> Vec<String> {
                vec![#schema_tokens]
            }

            fn get_column(&self, idx: usize) -> ParquetValue {
                #getter_implementation_tokens
                panic!("not supported column {:?}", idx);
            }
        }
    }
    .into()
}