redb_model_derive 0.12.0

Redb model derive macro
Documentation 
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//! Table metadata interpolation.
use syn::{
    punctuated::Punctuated,
    token::{Comma, PathSep},
    AngleBracketedGenericArguments, GenericArgument, Ident, Lifetime, Path, PathArguments,
    PathSegment, Token, Type, TypePath,
};

use crate::args::{ModelArgs, ModelTableType};

/// Metadata for table definitions.
pub(super) struct ModelMeta {
    ident: Ident,
    name: String,

    table_ty: ModelTableType,
}

impl ModelMeta {
    /// Create a new `ModelMeta` instance from the given `ModelArgs`.
    pub(super) fn new(args: ModelArgs) -> Self {
        let ident = args.ident;
        let name = args.name.unwrap_or_else(|| ident.to_string());
        let table_ty = args.table_type.unwrap_or(Default::default());

        Self {
            ident,
            name,
            table_ty,
        }
    }

    /// Get the table `Ident`.
    pub(super) fn ident(&self) -> &Ident {
        &self.ident
    }

    /// Get the table `name`.
    pub(super) fn name(&self) -> &str {
        &self.name
    }

    /// The table, or multimap table definition as a generic type.
    pub(crate) fn redb_ty(&self, k: &Type, v: &Type) -> Type {
        // Generic argumemnts.
        let mut args: Punctuated<_, Comma> = Punctuated::new();
        args.push(GenericArgument::Lifetime(Lifetime::new(
            "'static",
            self.ident.span(),
        )));
        args.push(GenericArgument::Type(k.clone()));
        args.push(GenericArgument::Type(v.clone()));
        let table_generics = PathArguments::AngleBracketed(AngleBracketedGenericArguments {
            colon2_token: None,
            lt_token: Token![<](self.ident.span()),
            args,
            gt_token: Token![>](self.ident.span()),
        });

        // Path segments.
        let mut segments: Punctuated<PathSegment, PathSep> = Punctuated::new();
        segments.push(PathSegment {
            ident: Ident::new("redb", self.ident.span()),
            arguments: syn::PathArguments::None,
        });
        match self.table_ty {
            ModelTableType::Table => {
                segments.push(PathSegment {
                    ident: Ident::new("TableDefinition", self.ident.span()),
                    arguments: table_generics,
                });
            }
            ModelTableType::Multimap => {
                segments.push(PathSegment {
                    ident: Ident::new("MultimapTableDefinition", self.ident.span()),
                    arguments: table_generics,
                });
            }
        }

        Type::Path(TypePath {
            qself: None,
            path: Path {
                leading_colon: None,
                segments,
            },
        })
    }
}