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
145
146
147
148
149
150
151
152
153
154

#[cfg(feature = "legacy")]
use macro_compose::{Collector, Lint};
#[cfg(feature = "legacy")]
use quote::ToTokens;
use std::convert::TryFrom;
#[cfg(feature = "legacy")]
use syn::Lit;
use syn::{parse_quote, Error, GenericArgument, Path, PathArguments};

#[derive(Clone, Copy, Debug)]
/// the type of a field
pub struct Type {
    /// the actual type
    pub ty: Types,
    /// whether or not the value for the type is optional
    pub optional: bool,
}

#[cfg(feature = "legacy")]
impl<'a> Lint<Option<&'a Lit>> for Type {
    fn lint(&self, input: &Option<&'a Lit>, c: &mut Collector) {
        let ty = match self.ty {
            Types::Any => "anything",
            Types::Flag => "nothing",
            Types::Str => "string",
            Types::ByteStr => "byte string",
            Types::Byte => "byte",
            Types::Char => "char",
            Types::I32 => "i32",
            Types::F32 => "f32",
            Types::Bool => "bool",
        };

        match (input, self.ty) {
            (Some(_), Types::Any)
            | (None, Types::Flag)
            | (Some(Lit::Str(_)), Types::Str)
            | (Some(Lit::ByteStr(_)), Types::ByteStr)
            | (Some(Lit::Byte(_)), Types::Byte)
            | (Some(Lit::Char(_)), Types::Char)
            | (Some(Lit::Int(_)), Types::I32)
            | (Some(Lit::Float(_)), Types::F32)
            | (Some(Lit::Bool(_)), Types::Bool) => {}
            (None, _) if self.optional => {}
            (Some(lit), _) => c.error(Error::new_spanned(
                input,
                format!("expected {}, got {}", ty, lit.to_token_stream()),
            )),
            (None, _) => c.error(Error::new_spanned(
                input,
                format!("expected {}, got nothing", ty,),
            )),
        }
    }
}
#[derive(Clone, Copy, Debug)]
/// all the types a field can contain
pub enum Types {
    /// can contain any literal
    Any,
    /// doesn't have a value eg `#[my_input(enabled)]`
    Flag,
    /// for string
    Str,
    /// for bytestring
    ByteStr,
    /// for u8
    Byte,
    /// for char
    Char,
    /// for i32
    I32,
    /// for f32
    F32,
    /// for bool
    Bool,
}

impl TryFrom<&syn::Type> for Type {
    type Error = Error;

    fn try_from(ty: &syn::Type) -> Result<Self, Self::Error> {
        let byte_vec_path: Path = parse_quote!(Vec<u8>);

        let error = || Err(Error::new_spanned(&ty, "unexpected type"));

        match ty {
            syn::Type::Path(p) => {
                if p.path.is_ident("String") {
                    Ok(Type {
                        ty: Types::Str,
                        optional: false,
                    })
                } else if p.path == byte_vec_path {
                    Ok(Type {
                        ty: Types::ByteStr,
                        optional: false,
                    })
                } else if p.path.is_ident("u8") {
                    Ok(Type {
                        ty: Types::Byte,
                        optional: false,
                    })
                } else if p.path.is_ident("char") {
                    Ok(Type {
                        ty: Types::Char,
                        optional: false,
                    })
                } else if p.path.is_ident("i32") {
                    Ok(Type {
                        ty: Types::I32,
                        optional: false,
                    })
                } else if p.path.is_ident("f32") {
                    Ok(Type {
                        ty: Types::F32,
                        optional: false,
                    })
                } else if p.path.is_ident("bool") {
                    Ok(Type {
                        ty: Types::Bool,
                        optional: false,
                    })
                } else {
                    if p.path.segments.len() == 1 {
                        let segment = p.path.segments.first().unwrap();
                        if segment.ident == "Option" {
                            if let PathArguments::AngleBracketed(args) = &segment.arguments {
                                if let Some(GenericArgument::Type(ty)) = args.args.first() {
                                    return Type::try_from(ty).and_then(|ty| {
                                        if ty.optional {
                                            error()
                                        } else {
                                            Ok(Type {
                                                ty: ty.ty,
                                                optional: true,
                                            })
                                        }
                                    });
                                }
                            }
                        }
                    }
                    error()
                }
            }
            syn::Type::Tuple(t) if t.elems.is_empty() => Ok(Type {
                ty: Types::Flag,
                optional: false,
            }),
            _ => error(),
        }
    }
}