1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144

use proc_macro2::{Ident, Literal, TokenStream};
use quote::{quote, ToTokens};
use syn::{DeriveInput, Lit, Meta, MetaList, NestedMeta};

enum AttributeType {
    Table,
    Pk,
    Unknown,
}

struct PkItem {
    column_name: Literal,
    field_name: Ident,
}

impl ToTokens for PkItem {
    fn to_tokens(&self, tokens: &mut TokenStream) {
        let (col_name, field_name) = (&self.column_name, &self.field_name);
        tokens.extend(quote! { (#col_name, &self.#field_name) });
    }
}

struct DbDataAttributes {
    table: Option<String>,
    pk: Option<Vec<PkItem>>,
}

impl From<&Ident> for AttributeType {
    fn from(ident: &Ident) -> Self {
        let str = format!("{}", ident);
        match str.as_str() {
            "orma_table" => AttributeType::Table,
            "orma_pk" => AttributeType::Pk,
            _ => AttributeType::Unknown,
        }
    }
}

pub fn impl_dbdata_macro(ast: &DeriveInput) -> TokenStream {
    let name = &ast.ident;

    let attrs = field_attrs(ast);
    let table = attrs.table.unwrap_or_else(|| format!("{}", name));
    let pk = attrs.pk.unwrap_or_else(|| vec![]);

    let gen = quote! {
        impl orma::DbData for #name {
            fn table_name() -> &'static str {
                #table
            }
            fn pk_filter(&self) -> Vec<(&str, &(dyn orma::ToSql + Sync))> {
                vec![#(#pk),*]
            }
        }
    };

    gen
}

impl DbDataAttributes {
    fn default() -> Self {
        Self {
            table: None,
            pk: None,
        }
    }
}

fn attribute_string_val(meta_list: &MetaList) -> String {
    let name_token = meta_list.nested.first().unwrap();
    match name_token {
        NestedMeta::Lit(lit) => {
            if let Lit::Str(lit_str) = lit {
                lit_str.value()
            } else {
                panic!("table attribute should be a string")
            }
        }
        _ => panic!("no value defined for macro attr"),
    }
}

fn lit_string(lit: &Lit) -> String {
    if let Lit::Str(lit_str) = lit {
        lit_str.value()
    } else {
        panic!("Invalid attr syntax {:?}", lit)
    }
}

fn kv_pk(kv_nested_meta: &NestedMeta) -> PkItem {
    match kv_nested_meta {
        NestedMeta::Meta(meta) => match meta {
            Meta::NameValue(name_value) => PkItem {
                field_name: name_value.path.get_ident().unwrap().clone(),
                column_name: Literal::string(&lit_string(&name_value.lit)),
            },
            _ => panic!("Invalid attr syntax {:?}", kv_nested_meta),
        },
        _ => panic!("Invalid attr syntax {:?}", kv_nested_meta),
    }
}

fn attribute_pk(meta_list: &MetaList) -> Vec<PkItem> {
    meta_list
        .nested
        .iter()
        .map(|kv_nested_meta| kv_pk(kv_nested_meta))
        .collect()
}

fn field_attrs(ast: &DeriveInput) -> DbDataAttributes {
    let mut ctx = DbDataAttributes::default();
    for attr in &ast.attrs {
        let attr: Meta = attr.parse_meta().unwrap();
        if let Meta::List(meta_list) = attr {
            let attr_type = AttributeType::from(meta_list.path.get_ident().unwrap());
            match attr_type {
                AttributeType::Table => ctx.table = Some(attribute_string_val(&meta_list)),
                AttributeType::Pk => ctx.pk = Some(attribute_pk(&meta_list)),
                _ => (),
            }
        };
    }
    ctx
}

#[cfg(test)]
mod tests {
    use super::*;
    use proc_macro2::Span;
    use std::str::FromStr;
    #[test]
    fn test_pk_to_token() {
        let pk = PkItem {
            column_name: Literal::string("column_name"),
            field_name: Ident::new("field_name", Span::call_site()),
        };

        let expected = TokenStream::from_str("(\"column_name\", &self.field_name)").unwrap();

        assert_eq!(format!("{}", expected), format!("{}", pk.to_token_stream()));
    }
}