df-derive-macros 0.3.0

Procedural derive macro implementation for df-derive.
Documentation 
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

use crate::ir::StructIR;
use quote::ToTokens;
use syn::{GenericArgument, GenericParam, Ident, PathArguments, Type};

#[allow(clippy::struct_field_names)]
pub(in crate::codegen) struct GenericContext {
    type_params: Vec<Ident>,
    const_params: Vec<Ident>,
    lifetime_params: Vec<Ident>,
}

impl GenericContext {
    pub(in crate::codegen) fn new(ir: &StructIR) -> Self {
        let mut type_params = Vec::new();
        let mut const_params = Vec::new();
        let mut lifetime_params = Vec::new();

        for param in &ir.generics.params {
            match param {
                GenericParam::Type(type_param) => type_params.push(type_param.ident.clone()),
                GenericParam::Const(const_param) => const_params.push(const_param.ident.clone()),
                GenericParam::Lifetime(lifetime_param) => {
                    lifetime_params.push(lifetime_param.lifetime.ident.clone());
                }
            }
        }

        Self {
            type_params,
            const_params,
            lifetime_params,
        }
    }

    fn has_type_param(&self, ident: &Ident) -> bool {
        self.type_params.iter().any(|param| param == ident)
    }

    fn has_lifetime_param(&self, ident: &Ident) -> bool {
        self.lifetime_params.iter().any(|param| param == ident)
    }

    const fn has_const_params(&self) -> bool {
        !self.const_params.is_empty()
    }
}

#[derive(PartialEq, Eq)]
struct TypeKey(String);

impl TypeKey {
    fn new(ty: &Type) -> Self {
        Self(ty.to_token_stream().to_string())
    }
}

pub(in crate::codegen) fn push_unique_type(out: &mut Vec<Type>, ty: &Type) {
    let key = TypeKey::new(ty);
    if !out.iter().any(|existing| TypeKey::new(existing) == key) {
        out.push(ty.clone());
    }
}

fn path_depends_on_generics(path: &syn::Path, generic_ctx: &GenericContext) -> bool {
    path.segments.iter().any(|segment| {
        if generic_ctx.has_type_param(&segment.ident) {
            return true;
        }

        let PathArguments::AngleBracketed(args) = &segment.arguments else {
            return false;
        };

        args.args
            .iter()
            .any(|arg| generic_argument_depends_on_generics(arg, generic_ctx))
    })
}

fn generic_argument_depends_on_generics(
    arg: &GenericArgument,
    generic_ctx: &GenericContext,
) -> bool {
    match arg {
        GenericArgument::Lifetime(lifetime) => generic_ctx.has_lifetime_param(&lifetime.ident),
        GenericArgument::Type(ty) => type_depends_on_generics(ty, generic_ctx),
        GenericArgument::Const(_) => generic_ctx.has_const_params(),
        GenericArgument::AssocType(assoc) => type_depends_on_generics(&assoc.ty, generic_ctx),
        GenericArgument::Constraint(constraint) => constraint.bounds.iter().any(|bound| {
            if let syn::TypeParamBound::Trait(trait_bound) = bound {
                path_depends_on_generics(&trait_bound.path, generic_ctx)
            } else {
                false
            }
        }),
        _ => false,
    }
}

pub(in crate::codegen) fn type_depends_on_generics(
    ty: &Type,
    generic_ctx: &GenericContext,
) -> bool {
    match ty {
        Type::Array(array) => {
            generic_ctx.has_const_params()
                || type_depends_on_generics(array.elem.as_ref(), generic_ctx)
        }
        Type::Group(group) => type_depends_on_generics(group.elem.as_ref(), generic_ctx),
        Type::Paren(paren) => type_depends_on_generics(paren.elem.as_ref(), generic_ctx),
        Type::Path(type_path) => {
            if let Some(qself) = &type_path.qself
                && type_depends_on_generics(qself.ty.as_ref(), generic_ctx)
            {
                return true;
            }

            if type_path.qself.is_none()
                && type_path.path.segments.len() == 1
                && let Some(segment) = type_path.path.segments.last()
                && matches!(segment.arguments, PathArguments::None)
                && generic_ctx.has_type_param(&segment.ident)
            {
                return true;
            }

            path_depends_on_generics(&type_path.path, generic_ctx)
        }
        Type::Ptr(ptr) => type_depends_on_generics(ptr.elem.as_ref(), generic_ctx),
        Type::Reference(reference) => {
            type_depends_on_generics(reference.elem.as_ref(), generic_ctx)
        }
        Type::Slice(slice) => type_depends_on_generics(slice.elem.as_ref(), generic_ctx),
        Type::Tuple(tuple) => tuple
            .elems
            .iter()
            .any(|elem| type_depends_on_generics(elem, generic_ctx)),
        _ => false,
    }
}