engine/transaction_derive/src/tracker_field.rs

use quote::{format_ident, quote, ToTokens};
use syn::Ident;

use crate::attribute_info::*;
use crate::data_type::*;
use crate::transaction_field::*;

pub struct TrackerField<'a> {
    pub variable_name: &'a Ident,
    pub data_type: &'a DataType,
    pub convert_type: Option<&'a proc_macro2::TokenStream>,
    pub attribute_infos: &'a Vec<AttributeInfo>,
}

impl<'a> From<&'a TransactionField> for TrackerField<'a> {
    fn from(transaction_field: &'a TransactionField) -> Self {
        let convert_type = AttributeInfo::find_convert_type(&transaction_field.attribute_infos);

        Self {
            variable_name: &transaction_field.variable_name,
            data_type: &transaction_field.data_type,
            convert_type,
            attribute_infos: &transaction_field.attribute_infos,
        }
    }
}

pub struct TrackerDataType<'a> {
    pub variable_name: &'a Ident,
    pub data_type: &'a DataType,
    pub convert_type: &'a Option<&'a proc_macro2::TokenStream>,
    pub attribute_infos: &'a Vec<AttributeInfo>,
}

impl<'a> From<&'a TrackerField<'a>> for TrackerDataType<'a> {
    fn from(tracker_field: &'a TrackerField) -> Self {
        Self {
            variable_name: &tracker_field.variable_name,
            data_type: &tracker_field.data_type,
            convert_type: &tracker_field.convert_type,
            attribute_infos: &tracker_field.attribute_infos,
        }
    }
}

impl<'a> ToTokens for TrackerDataType<'a> {
    fn to_tokens(&self, tokens: &mut proc_macro2::TokenStream) {
        let variable_name = &self.variable_name;
        let track = format_ident!("track_{}", variable_name);
        let last_change = format_ident!("{}_last_change", variable_name);

        // figure out the type of the variable
        let quote = match self.data_type {
            DataType::Array(array) => {
                let length = &array.length;

                match self.convert_type {
                    Some(convert_type) => {
                        quote! {
                            #variable_name: [Option<#convert_type>; #length],
                        }
                    }
                    None => {
                        let inner = &array.inner_type;

                        quote! {
                            #variable_name: [Option<#inner>; #length],
                        }
                    }
                }
            }
            DataType::Vector(vector) => match self.convert_type {
                Some(convert_type) => {
                    quote! {
                        #variable_name: Vec<Option<#convert_type>>,
                    }
                }
                None => {
                    let inner = &vector.inner_type;

                    quote! {
                        #variable_name: Vec<Option<#inner>>,
                    }
                }
            },
            DataType::Other(ts) => match self.convert_type {
                Some(convert_type) => {
                    quote! {
                        #variable_name: Option<#convert_type>,
                    }
                }
                None => {
                    quote! {
                        #variable_name: Option<#ts>,
                    }
                }
            },
        };

        // check features
        AttributeInfo::set_features(&self.attribute_infos, tokens);

        // set variable type
        proc_macro2::TokenStream::from(quote).to_tokens(tokens);

        // check features
        AttributeInfo::set_features(&self.attribute_infos, tokens);

        // flag, if variable gets tracked
        proc_macro2::TokenStream::from(quote! {
            #track: bool,
        })
        .to_tokens(tokens);

        // check features
        AttributeInfo::set_features(&self.attribute_infos, tokens);

        // track the time the variable got changed last time
        proc_macro2::TokenStream::from(match self.data_type {
            DataType::Array(array) => {
                let length = &array.length;

                quote! {#last_change: [std::time::Duration; #length],}
            }
            DataType::Vector(_) => {
                quote! {#last_change: Vec<std::time::Duration>,}
            }
            DataType::Other(_) => {
                quote! {#last_change: std::time::Duration,}
            }
        })
        .to_tokens(tokens);
    }
}

pub struct TrackerDefault<'a> {
    pub variable_name: &'a Ident,
    pub attribute_infos: &'a Vec<AttributeInfo>,
}

impl<'a> From<&'a TrackerDataType<'a>> for TrackerDefault<'a> {
    fn from(tracker_field: &'a TrackerDataType) -> Self {
        Self {
            variable_name: &tracker_field.variable_name,
            attribute_infos: &tracker_field.attribute_infos,
        }
    }
}

impl<'a> ToTokens for TrackerDefault<'a> {
    fn to_tokens(&self, tokens: &mut proc_macro2::TokenStream) {
        let variable_name = &self.variable_name;
        let track = format_ident!("track_{}", variable_name);
        let last_change = format_ident!("{}_last_change", variable_name);

        // check features
        AttributeInfo::set_features(&self.attribute_infos, tokens);

        proc_macro2::TokenStream::from(quote! {
            #variable_name: Default::default(),
        })
        .to_tokens(tokens);

        // check features
        AttributeInfo::set_features(&self.attribute_infos, tokens);

        proc_macro2::TokenStream::from(quote! {
            #track: true,
        })
        .to_tokens(tokens);

        // check features
        AttributeInfo::set_features(&self.attribute_infos, tokens);

        proc_macro2::TokenStream::from(quote! {
            #last_change: Default::default(),
        })
        .to_tokens(tokens);
    }
}