ortho_config_macros 0.9.0

Procedural macros for ortho_config.
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
141

//! Collection token generation for declarative merge.
//!
//! Generates tokens for handling append-strategy vectors and replace-strategy
//! maps during the declarative merge process.

use proc_macro2::TokenStream;
use quote::{format_ident, quote};
use std::collections::HashSet;

use crate::derive::build::CollectionStrategies;

pub(super) struct CollectionTokens {
    pub merge_logic: Vec<TokenStream>,
    pub destructured: Vec<TokenStream>,
    pub inserts: Vec<TokenStream>,
}

fn build_collection_tokens<'a, I, F, G>(
    fields: I,
    prefix: &str,
    merge_fn: F,
    insert_fn: G,
) -> CollectionTokens
where
    I: IntoIterator<Item = (&'a syn::Ident, &'a syn::Type)>,
    F: Fn(&syn::Ident, &proc_macro2::Ident, &str) -> TokenStream,
    G: Fn(&syn::Ident, &proc_macro2::Ident, &str) -> TokenStream,
{
    let mut merge_logic = Vec::new();
    let mut destructured = Vec::new();
    let mut inserts = Vec::new();

    for (field_ident, _ty) in fields {
        let state_field_ident = format_ident!("{}{}", prefix, field_ident);
        let field_name = field_ident.to_string();
        merge_logic.push(merge_fn(field_ident, &state_field_ident, &field_name));
        destructured.push(quote! { #state_field_ident });
        inserts.push(insert_fn(field_ident, &state_field_ident, &field_name));
    }

    CollectionTokens {
        merge_logic,
        destructured,
        inserts,
    }
}

pub(super) fn append_collection_tokens(
    strategies: &CollectionStrategies,
    krate: &TokenStream,
) -> CollectionTokens {
    build_collection_tokens(
        unique_append_fields(&strategies.append),
        "append_",
        |_, state_field_ident, field_name| {
            quote! {
                if let Some(value) = map.remove(#field_name) {
                    if value.is_null() {
                        self.#state_field_ident = Some(Vec::new());
                    } else {
                        let normalised = match value {
                            #krate::serde_json::Value::Array(_) => value,
                            other => #krate::serde_json::Value::Array(vec![other]),
                        };
                        let incoming: Vec<_> =
                            #krate::declarative::from_value_merge(normalised)?;
                        let acc = self
                            .#state_field_ident
                            .get_or_insert_with(Default::default);
                        acc.extend(incoming);
                    }
                }
            }
        },
        |_, state_field_ident, field_name| {
            quote! {
                if let Some(values) = #state_field_ident {
                    overlay.insert(
                        #field_name.to_owned(),
                        #krate::serde_json::Value::Array(values),
                    );
                }
            }
        },
    )
}

pub(super) fn map_collection_tokens(strategies: &CollectionStrategies) -> CollectionTokens {
    build_collection_tokens(
        strategies.map_replace.iter().map(|(ident, ty)| (ident, ty)),
        "replace_",
        |_, state_field_ident, field_name| {
            quote! {
                if let Some(value) = map.remove(#field_name) {
                    self.#state_field_ident = Some(value);
                }
            }
        },
        |_, state_field_ident, field_name| {
            quote! {
                if let Some(value) = #state_field_ident {
                    overlay.insert(#field_name.to_owned(), value);
                }
            }
        },
    )
}

/// Deduplicate append fields by identifier.
///
/// Returns a vector of unique `(ident, type)` pairs, preserving the first
/// occurrence for each identifier in the input slice.
///
/// # Examples
///
/// ```rust,ignore
/// use syn::parse_str;
///
/// let fields = vec![
///     (parse_str("items").unwrap(), parse_str("String").unwrap()),
///     (parse_str("items").unwrap(), parse_str("String").unwrap()),
///     (parse_str("tags").unwrap(), parse_str("String").unwrap()),
/// ];
///
/// let unique = unique_append_fields(&fields);
/// assert_eq!(unique.len(), 2);
/// assert_eq!(unique[0].0.to_string(), "items");
/// assert_eq!(unique[1].0.to_string(), "tags");
/// ```
pub(crate) fn unique_append_fields(
    append_fields: &[(syn::Ident, syn::Type)],
) -> Vec<(&syn::Ident, &syn::Type)> {
    let mut seen = HashSet::new();
    append_fields
        .iter()
        .filter_map(|(ident, ty)| {
            let key = ident.to_string();
            seen.insert(key).then_some((ident, ty))
        })
        .collect()
}