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

#![cfg_attr(feature = "clippy", feature(plugin))]
#![cfg_attr(feature = "clippy", plugin(clippy))]
#![recursion_limit = "128"]

extern crate diesel;
extern crate diesel_derives_traits;
extern crate proc_macro;
#[macro_use]
extern crate quote;
extern crate syn;

use proc_macro::TokenStream;
use quote::{ToTokens, Tokens};
use syn::{parse_derive_input, DeriveInput};

#[proc_macro_derive(Model)]
pub fn derive_model(input: TokenStream) -> TokenStream {
    expand_derive(&input, impl_model)
}

fn impl_model(item: &DeriveInput) -> Tokens {
    let name = &item.ident;

    quote! (
        impl<'a> ::diesel_derives_traits::Model<'a> for #name
        {
            fn save(self, conn: &::diesel::PgConnection) -> ::diesel::result::QueryResult<Self> {
                ::diesel::RunQueryDsl::get_result(
                    ::diesel::update(
                        &self
                    )
                    .set(&self),
                    conn
                )
                .map_err(|e| e.into())
            }

            fn find_all(conn: &::diesel::PgConnection) -> ::diesel::result::QueryResult<Vec<Self>> {
                ::diesel::RunQueryDsl::load(
                    <Self as ::diesel::associations::HasTable>::table(),
                    conn
                )
                .map_err(|e| e.into())
            }

            fn find_one(conn: &::diesel::PgConnection, id: <&'a Self as ::diesel::Identifiable>::Id) -> ::diesel::result::QueryResult<Option<Self>> {
                use diesel::{OptionalExtension, QueryDsl};

                ::diesel::RunQueryDsl::get_result(
                    <Self as ::diesel::associations::HasTable>::table().find(id),
                    conn
                )
                .optional()
                .map_err(|e| e.into())
            }

            fn exists(conn: &::diesel::PgConnection, id: <&'a Self as ::diesel::associations::Identifiable>::Id) -> ::diesel::result::QueryResult<bool> {
                use diesel::QueryDsl;

                ::diesel::RunQueryDsl::get_result(
                    ::diesel::select(::diesel::dsl::exists(<Self as ::diesel::associations::HasTable>::table().find(id))),
                    conn
                )
                .map_err(|e| e.into())
            }

            fn count_all(conn: &::diesel::PgConnection) -> ::diesel::result::QueryResult<i64> {
                use diesel::QueryDsl;

                ::diesel::RunQueryDsl::get_result(
                    <Self as ::diesel::associations::HasTable>::table().count(),
                    conn
                )
                .map_err(|e| e.into())
            }

            fn destroy(self, conn: &::diesel::PgConnection) -> ::diesel::result::QueryResult<()> {
                ::diesel::RunQueryDsl::execute(
                    ::diesel::delete(&self),
                    conn
                )?;
                Ok(())
            }
        }
    )
}

#[proc_macro_derive(NewModel, attributes(model))]
pub fn derive_new_model(input: TokenStream) -> TokenStream {
    expand_derive(&input, impl_new_model)
}

fn impl_new_model(item: &syn::DeriveInput) -> Tokens {
    let name = &item.ident;
    let mut tokens = Tokens::new();
    name.to_tokens(&mut tokens);
    item.generics.to_tokens(&mut tokens);
    let target = item.attrs
        .iter()
        .find(|attr| attr.name() == "model")
        .expect("\"model\" attribute must be specified for #[derive(NewModel)]");
    let target_name = match target.value {
        syn::MetaItem::List(_, ref options) if options.len() >= 1 => match options[0] {
            syn::NestedMetaItem::MetaItem(syn::MetaItem::Word(ref name)) => name.clone(),
            _ => panic!("Must be in the form of `#[model(MyModel)]`"),
        },
        _ => panic!("Must be in the form of `#[model(MyModel)]`"),
    };

    quote! (
        impl<'a> ::diesel_derives_traits::NewModel<'a, #target_name> for #tokens
        {
            fn save(self, conn: &::diesel::PgConnection) -> ::diesel::result::QueryResult<#target_name> {
                ::diesel::RunQueryDsl::get_result(
                    ::diesel::insert_into(<#target_name as ::diesel::associations::HasTable>::table())
                        .values(&self),
                    conn
                )
                .map_err(|e| e.into())
            }
        }
    )
}

fn expand_derive(input: &TokenStream, f: fn(&DeriveInput) -> Tokens) -> TokenStream {
    let item = parse_derive_input(&input.to_string()).unwrap();
    f(&item).to_string().parse().unwrap()
}