icydb_core/db/schema_evolution/
registry.rs

1//! Module: db::schema_evolution::registry
2//! Responsibility: completed schema-migration registry contract.
3//! Does not own: durable commit layout or in-progress migration cursor storage.
4//! Boundary: schema-evolution guard state consumed before migration execution.
5
6use crate::db::identity::EntityName;
7use std::collections::BTreeSet;
8
9///
10/// MigrationRegistryKey
11///
12/// MigrationRegistryKey names one completed schema migration by canonical
13/// migration identity plus monotonic version.
14/// The registry uses this key to reject repeat execution before the lower
15/// migration engine is invoked.
16///
17
18#[derive(Clone, Copy, Debug, Eq, Ord, PartialEq, PartialOrd)]
19pub struct MigrationRegistryKey {
20    migration_id: EntityName,
21    version: u64,
22}
23
24impl MigrationRegistryKey {
25    /// Build one registry key from canonical migration identity.
26    #[must_use]
27    pub const fn new(migration_id: EntityName, version: u64) -> Self {
28        Self {
29            migration_id,
30            version,
31        }
32    }
33
34    /// Return the canonical migration identity.
35    #[must_use]
36    pub const fn migration_id(self) -> EntityName {
37        self.migration_id
38    }
39
40    /// Return the monotonic migration version.
41    #[must_use]
42    pub const fn version(self) -> u64 {
43        self.version
44    }
45}
46
47///
48/// MigrationRegistry
49///
50/// MigrationRegistry tracks schema migrations that have completed above the
51/// lower `db::migration` execution engine.
52/// This first implementation is an explicit owner object so no commit/storage
53/// layout changes are required by the schema-evolution slice.
54///
55
56#[derive(Clone, Debug, Default)]
57pub struct MigrationRegistry {
58    completed: BTreeSet<MigrationRegistryKey>,
59}
60
61impl MigrationRegistry {
62    /// Build one empty completed-migration registry.
63    #[must_use]
64    pub const fn new() -> Self {
65        Self {
66            completed: BTreeSet::new(),
67        }
68    }
69
70    /// Return whether the migration id/version is already recorded as complete.
71    #[must_use]
72    pub fn is_applied(&self, migration_id: EntityName, version: u64) -> bool {
73        self.completed
74            .contains(&MigrationRegistryKey::new(migration_id, version))
75    }
76
77    /// Record one migration id/version as complete.
78    pub fn record_applied(&mut self, migration_id: EntityName, version: u64) {
79        self.completed
80            .insert(MigrationRegistryKey::new(migration_id, version));
81    }
82
83    /// Return the number of completed migration keys tracked by this registry.
84    #[must_use]
85    pub fn len(&self) -> usize {
86        self.completed.len()
87    }
88
89    /// Return whether this registry currently has no completed migration keys.
90    #[must_use]
91    pub fn is_empty(&self) -> bool {
92        self.completed.is_empty()
93    }
94}
icydb_core/db/schema_evolution/registry.rs

icydb_core/db/schema_evolution/
registry.rs
