time_macros/
serde_format_description.rs

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
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
use proc_macro::{Ident, TokenStream, TokenTree};

pub(crate) fn build(
    mod_name: Ident,
    ty: TokenTree,
    format: TokenStream,
    format_description_display: String,
) -> TokenStream {
    let ty_s = &*ty.to_string();

    let visitor = if cfg!(feature = "parsing") {
        quote! {
            struct Visitor;
            struct OptionVisitor;

            impl<'a> ::serde::de::Visitor<'a> for Visitor {
                type Value = __TimeSerdeType;

                fn expecting(&self, f: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result {
                    write!(
                        f,
                        concat!(
                            "a(n) `",
                            #(ty_s),
                            "` in the format \"{}\"",
                        ),
                        #(format_description_display.as_str())
                    )
                }

                fn visit_str<E: ::serde::de::Error>(
                    self,
                    value: &str
                ) -> Result<__TimeSerdeType, E> {
                    __TimeSerdeType::parse(value, &description()).map_err(E::custom)
                }
            }

            impl<'a> ::serde::de::Visitor<'a> for OptionVisitor {
                type Value = Option<__TimeSerdeType>;

                fn expecting(&self, f: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result {
                    write!(
                        f,
                        concat!(
                            "an `Option<",
                            #(ty_s),
                            ">` in the format \"{}\"",
                        ),
                        #(format_description_display.as_str())
                    )
                }

                fn visit_some<D: ::serde::de::Deserializer<'a>>(
                    self,
                    deserializer: D
                ) -> Result<Option<__TimeSerdeType>, D::Error> {
                    deserializer
                        .deserialize_str(Visitor)
                        .map(Some)
                }

                fn visit_none<E: ::serde::de::Error>(
                    self
                ) -> Result<Option<__TimeSerdeType>, E> {
                    Ok(None)
                }
            }
        }
    } else {
        quote!()
    };

    let serialize_primary = if cfg!(feature = "formatting") {
        quote! {
            pub fn serialize<S: ::serde::Serializer>(
                datetime: &__TimeSerdeType,
                serializer: S,
            ) -> Result<S::Ok, S::Error> {
                use ::serde::Serialize;
                datetime
                    .format(&description())
                    .map_err(::time::error::Format::into_invalid_serde_value::<S>)?
                    .serialize(serializer)
            }
        }
    } else {
        quote!()
    };

    let deserialize_primary = if cfg!(feature = "parsing") {
        quote! {
            pub fn deserialize<'a, D: ::serde::Deserializer<'a>>(
                deserializer: D
            ) -> Result<__TimeSerdeType, D::Error> {
                use ::serde::Deserialize;
                deserializer.deserialize_str(Visitor)
            }
        }
    } else {
        quote!()
    };

    let serialize_option = if cfg!(feature = "formatting") {
        quote! {
            pub fn serialize<S: ::serde::Serializer>(
                option: &Option<__TimeSerdeType>,
                serializer: S,
            ) -> Result<S::Ok, S::Error> {
                use ::serde::Serialize;
                option.map(|datetime| datetime.format(&description()))
                    .transpose()
                    .map_err(::time::error::Format::into_invalid_serde_value::<S>)?
                    .serialize(serializer)
            }
        }
    } else {
        quote!()
    };

    let deserialize_option = if cfg!(feature = "parsing") {
        quote! {
            pub fn deserialize<'a, D: ::serde::Deserializer<'a>>(
                deserializer: D
            ) -> Result<Option<__TimeSerdeType>, D::Error> {
                use ::serde::Deserialize;
                deserializer.deserialize_option(OptionVisitor)
            }
        }
    } else {
        quote!()
    };

    let deserialize_option_imports = if cfg!(feature = "parsing") {
        quote! {
            use super::{OptionVisitor, Visitor};
        }
    } else {
        quote!()
    };

    let fd_traits = match (cfg!(feature = "formatting"), cfg!(feature = "parsing")) {
        (false, false) => {
            bug!("serde_format_description::build called without formatting or parsing enabled")
        }
        (false, true) => quote! { ::time::parsing::Parsable },
        (true, false) => quote! { ::time::formatting::Formattable },
        (true, true) => quote! { ::time::formatting::Formattable + ::time::parsing::Parsable },
    };

    quote! {
        mod #(mod_name) {
            use ::time::#(ty) as __TimeSerdeType;

            const fn description() -> impl #S(fd_traits) {
                #S(format)
            }

            #S(visitor)
            #S(serialize_primary)
            #S(deserialize_primary)

            pub(super) mod option {
                use super::{description, __TimeSerdeType};
                #S(deserialize_option_imports)

                #S(serialize_option)
                #S(deserialize_option)
            }
        }
    }
}