uqa_sql/ast/types/
identity.rs

1//
2// Unified Query Algebra
3//
4// Copyright (c) 2023-2026 Cognica, Inc.
5//
6
7//! OID identities of user-defined types. Stored syntax, routine signatures and bound casts name a user-defined type by identity, so a rename, a schema move or a different search path cannot change which type they mean; output spells the type's current name. `#` cannot occur in an unquoted type name, and quoted names keep their quotes, so an identity never collides with a name as written.
8
9use super::ColumnType;
10
11const ENUM_PREFIX: &str = "enum#";
12const DOMAIN_PREFIX: &str = "domain#";
13const COMPOSITE_PREFIX: &str = "composite#";
14
15pub(super) fn write_identity(ty: &ColumnType, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
16    match ty {
17        ColumnType::Enum(reference) => write!(f, "{ENUM_PREFIX}{}", reference.oid),
18        ColumnType::Composite(reference) => write!(f, "{COMPOSITE_PREFIX}{}", reference.oid),
19        ColumnType::Domain { oid, .. } => write!(f, "{DOMAIN_PREFIX}{oid}"),
20        _ => unreachable!("catalog identity formatter requires a user-defined scalar type"),
21    }
22}
23
24#[derive(Debug, Clone, Copy, PartialEq, Eq)]
25pub enum UserTypeKind {
26    Enum,
27    Domain,
28    Composite,
29}
30
31/// A parsed identity: the type's kind and OID, and the number of array dimensions around it.
32#[derive(Debug, Clone, Copy, PartialEq, Eq)]
33pub struct UserTypeIdentity {
34    pub kind: UserTypeKind,
35    pub oid: u32,
36    pub dimensions: usize,
37}
38
39impl UserTypeIdentity {
40    /// Parse `enum#<oid>`, `domain#<oid>` or `composite#<oid>` with any number of `[]` suffixes.
41    #[must_use]
42    pub fn parse(name: &str) -> Option<Self> {
43        let mut element = name.trim();
44        let mut dimensions = 0usize;
45        while let Some(inner) = element.strip_suffix("[]") {
46            element = inner;
47            dimensions += 1;
48        }
49        let (kind, oid) = if let Some(oid) = element.strip_prefix(ENUM_PREFIX) {
50            (UserTypeKind::Enum, oid)
51        } else if let Some(oid) = element.strip_prefix(COMPOSITE_PREFIX) {
52            (UserTypeKind::Composite, oid)
53        } else {
54            (UserTypeKind::Domain, element.strip_prefix(DOMAIN_PREFIX)?)
55        };
56        if oid.is_empty() || !oid.bytes().all(|byte| byte.is_ascii_digit()) {
57            return None;
58        }
59        Some(Self {
60            kind,
61            oid: oid.parse().ok()?,
62            dimensions,
63        })
64    }
65}
66
67impl ColumnType {
68    /// The identity of a user-defined type or an array of one; built-in types have none.
69    #[must_use]
70    pub fn user_type_identity(&self) -> Option<String> {
71        match self {
72            ColumnType::Enum(reference) => Some(format!("{ENUM_PREFIX}{}", reference.oid)),
73            ColumnType::Composite(reference) => {
74                Some(format!("{COMPOSITE_PREFIX}{}", reference.oid))
75            }
76            ColumnType::Domain { oid, .. } => Some(format!("{DOMAIN_PREFIX}{oid}")),
77            ColumnType::Array(element) => element
78                .user_type_identity()
79                .map(|element| format!("{element}[]")),
80            _ => None,
81        }
82    }
83}
84
85#[cfg(test)]
86mod tests {
87    use super::{UserTypeIdentity, UserTypeKind};
88    use crate::ast::{ColumnType, EnumTypeReference};
89
90    #[test]
91    fn identities_round_trip_through_arrays() {
92        let mood = ColumnType::Enum(EnumTypeReference {
93            schema: "public".into(),
94            name: "mood".into(),
95            oid: 20_000,
96            array_oid: 20_001,
97        });
98        let array = ColumnType::Array(Box::new(ColumnType::Array(Box::new(mood))));
99        let identity = array.user_type_identity().unwrap();
100        assert_eq!(identity, "enum#20000[][]");
101        assert_eq!(
102            UserTypeIdentity::parse(&identity),
103            Some(UserTypeIdentity {
104                kind: UserTypeKind::Enum,
105                oid: 20_000,
106                dimensions: 2,
107            })
108        );
109        assert_eq!(
110            UserTypeIdentity::parse("composite#9[]"),
111            Some(UserTypeIdentity {
112                kind: UserTypeKind::Composite,
113                oid: 9,
114                dimensions: 1,
115            })
116        );
117        assert_eq!(
118            UserTypeIdentity::parse("domain#7"),
119            Some(UserTypeIdentity {
120                kind: UserTypeKind::Domain,
121                oid: 7,
122                dimensions: 0,
123            })
124        );
125        for name in ["\"enum#1\"", "enum#", "enum#x", "domain#-1", "integer"] {
126            assert_eq!(UserTypeIdentity::parse(name), None, "{name}");
127        }
128        assert_eq!(ColumnType::Integer.user_type_identity(), None);
129    }
130}
uqa_sql/ast/types/identity.rs

uqa_sql/ast/types/
identity.rs
