truc 0.4.0

Rust code generator for safe, fixed size, evolving records.
Documentation 
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use codegen::Scope;

use super::{FragmentGenerator, FragmentGeneratorSpecs};
use crate::generator::{CAP, CAP_GENERIC};

pub struct DropImplGenerator;

impl FragmentGenerator for DropImplGenerator {
    fn generate(&self, specs: &FragmentGeneratorSpecs, scope: &mut Scope) {
        let record_spec = &specs.record;

        let drop_impl = scope
            .new_impl(&record_spec.capped_record_name)
            .generic(CAP_GENERIC)
            .target_generic(CAP)
            .impl_trait("Drop");

        let drop_fn = drop_impl.new_fn("drop").arg_mut_self();

        for datum in &record_spec.data {
            drop_fn.line(format!(
                "let _{}: {} = unsafe {{ self.data.read({}) }};",
                datum.name(),
                datum.details().type_name(),
                datum.details().offset(),
            ));
        }
    }
}

#[cfg(test)]
#[cfg_attr(coverage_nightly, coverage(off))]
mod tests {
    use std::collections::BTreeSet;

    use maplit::btreeset;
    use pretty_assertions::assert_eq;

    use super::*;
    use crate::{
        generator::{config::GeneratorConfig, generate_variant, tests::assert_fragment_eq},
        record::{
            definition::builder::native::NativeRecordDefinitionBuilder,
            type_resolver::HostTypeResolver,
        },
    };

    #[test]
    fn should_generate_empty_drop_impl() {
        let mut builder = NativeRecordDefinitionBuilder::new(HostTypeResolver);
        builder.close_record_variant();
        let definition = builder.build();

        let config =
            GeneratorConfig::new([Box::new(DropImplGenerator) as Box<dyn FragmentGenerator>]);

        let mut scope = Scope::new();
        let mut type_size_assertions = BTreeSet::new();

        generate_variant(
            &definition,
            definition.max_type_align(),
            definition.variants().next().expect("variant"),
            None,
            &config,
            &mut scope,
            &mut type_size_assertions,
        );

        assert_fragment_eq(
            r#"
impl<const CAP: usize> Drop for CappedRecord0<CAP> {
    fn drop(&mut self) {
    }
}
"#,
            &scope.to_string(),
        );

        assert_eq!(btreeset![], type_size_assertions);
    }

    #[test]
    fn should_generate_drop_impl_with_data() {
        let mut builder = NativeRecordDefinitionBuilder::new(HostTypeResolver);
        builder.add_datum_allow_uninit::<u32, _>("integer").unwrap();
        builder.add_datum::<u32, _>("not_copy_integer").unwrap();
        builder.close_record_variant();
        let definition = builder.build();

        let config =
            GeneratorConfig::new([Box::new(DropImplGenerator) as Box<dyn FragmentGenerator>]);

        let mut scope = Scope::new();
        let mut type_size_assertions = BTreeSet::new();

        generate_variant(
            &definition,
            definition.max_type_align(),
            definition.variants().next().expect("variant"),
            None,
            &config,
            &mut scope,
            &mut type_size_assertions,
        );

        assert_fragment_eq(
            r#"
impl<const CAP: usize> Drop for CappedRecord0<CAP> {
    fn drop(&mut self) {
        let _integer: u32 = unsafe { self.data.read(0) };
        let _not_copy_integer: u32 = unsafe { self.data.read(4) };
    }
}
"#,
            &scope.to_string(),
        );

        assert_eq!(
            btreeset![("u32", std::mem::size_of::<u32>())],
            type_size_assertions
        );
    }

    #[test]
    fn should_generate_next_drop_impl_with_data() {
        let mut builder = NativeRecordDefinitionBuilder::new(HostTypeResolver);
        let i0 = builder
            .add_datum_allow_uninit::<u32, _>("integer0")
            .unwrap();
        let nci0 = builder.add_datum::<u32, _>("not_copy_integer0").unwrap();
        builder
            .add_datum_allow_uninit::<bool, _>("boolean1")
            .unwrap();
        builder.close_record_variant();
        builder.remove_datum(i0).unwrap();
        builder.remove_datum(nci0).unwrap();
        builder
            .add_datum_allow_uninit::<u32, _>("integer1")
            .unwrap();
        builder.add_datum::<u32, _>("not_copy_integer1").unwrap();
        builder.close_record_variant();
        let definition = builder.build();

        let config =
            GeneratorConfig::new([Box::new(DropImplGenerator) as Box<dyn FragmentGenerator>]);

        let mut scope = Scope::new();
        let mut type_size_assertions = BTreeSet::new();

        let record0_spec = generate_variant(
            &definition,
            definition.max_type_align(),
            definition.variants().next().expect("variant"),
            None,
            &config,
            &mut scope,
            &mut type_size_assertions,
        );
        let mut scope = Scope::new();
        type_size_assertions.clear();
        generate_variant(
            &definition,
            definition.max_type_align(),
            definition.variants().nth(1).expect("variant"),
            Some(&record0_spec),
            &config,
            &mut scope,
            &mut type_size_assertions,
        );

        assert_fragment_eq(
            r#"
impl<const CAP: usize> Drop for CappedRecord1<CAP> {
    fn drop(&mut self) {
        let _boolean1: bool = unsafe { self.data.read(8) };
        let _integer1: u32 = unsafe { self.data.read(0) };
        let _not_copy_integer1: u32 = unsafe { self.data.read(4) };
    }
}
"#,
            &scope.to_string(),
        );

        assert_eq!(
            btreeset![("u32", std::mem::size_of::<u32>())],
            type_size_assertions
        );
    }
}