icydb-model 0.217.0

IcyDB application-model authoring, validation, and code generation
Documentation 
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//! Module: db::schema
//! Responsibility: generated accepted-schema report capability tokens.
//! Does not own: schema validation, entity description semantics, or controller policy.
//! Boundary: emits only the private accepted-schema handler for immutable
//! authored entity identities.

use proc_macro2::TokenStream;
use quote::quote;

///
/// SchemaSurfaceTokens
///
/// Generated token bundle for the private accepted-schema report capability.
///

pub(super) struct SchemaSurfaceTokens {
    entity_sources: Vec<String>,
}

impl SchemaSurfaceTokens {
    pub(super) const fn empty() -> Self {
        Self {
            entity_sources: Vec::new(),
        }
    }

    pub(super) fn push_entity(&mut self, entity_source: &str) {
        self.entity_sources.push(entity_source.to_owned());
    }
}

impl quote::ToTokens for SchemaSurfaceTokens {
    fn to_tokens(&self, tokens: &mut TokenStream) {
        let entity_sources = &self.entity_sources;

        tokens.extend(quote! {
            #[allow(clippy::missing_const_for_fn, clippy::unnecessary_wraps)]
            pub(crate) fn __icydb_endpoint_handler_schema() -> Result<Vec<::icydb::db::EntitySchemaDescription>, ::icydb::Error> {
                Ok(vec![
                    #(db()?.try_describe_entity_by_source_key(#entity_sources)?),*
                ])
            }
        });
    }
}

#[cfg(test)]
mod tests {
    use quote::quote;

    use super::SchemaSurfaceTokens;

    fn compact_tokens(tokens: proc_macro2::TokenStream) -> String {
        tokens
            .to_string()
            .chars()
            .filter(|character| !character.is_whitespace())
            .collect()
    }

    #[test]
    fn generated_schema_capability_resolves_current_entity_names_privately() {
        let mut surface_tokens = SchemaSurfaceTokens::empty();
        surface_tokens.push_entity("Character");

        let surface = compact_tokens(quote!(#surface_tokens));

        assert!(surface.contains("fn__icydb_endpoint_handler_schema("));
        assert!(surface.contains("try_describe_entity_by_source_key(\"Character\")"));
        assert!(!surface.contains("crate::Character"));
        assert!(!surface.contains("icydb_schema"));
        assert!(!surface.contains("ic_cdk::query"));
    }

    #[test]
    fn generated_schema_private_handler_cannot_export_a_method() {
        let mut surface_tokens = SchemaSurfaceTokens::empty();
        surface_tokens.push_entity("Character");
        let file = syn::parse2::<syn::File>(quote!(#surface_tokens))
            .expect("generated schema surface should remain valid Rust syntax");
        let handler = file
            .items
            .into_iter()
            .find_map(|item| match item {
                syn::Item::Fn(function)
                    if function.sig.ident == "__icydb_endpoint_handler_schema" =>
                {
                    Some(function)
                }
                _ => None,
            })
            .expect("generated schema surface should contain its private handler");

        assert!(matches!(handler.vis, syn::Visibility::Restricted(_)));
        assert_eq!(handler.attrs.len(), 1);
        assert!(
            handler
                .attrs
                .iter()
                .all(|attribute| attribute.path().is_ident("allow"))
        );
    }
}