Mailbox roles must be unique per archive (fixes #8)

src/db/mod.rs

@@ -14,6 +14,7 @@ pub mod imap_state;
 pub mod init;
 pub mod maildir_ids;
 pub mod managesieve_ids;
+pub mod roles;
 pub mod sources;
 pub mod sync_state_jmap;
 pub mod takeout_ids;

src/db/roles.rs

@@ -0,0 +1,90 @@
+/*
+ * SPDX-FileCopyrightText: 2020 Stalwart Labs LLC <[email protected]>
+ *
+ * SPDX-License-Identifier: Apache-2.0 OR MIT
+ */
+
+use rusqlite::{Connection, params};
+
+pub fn unique_role(
+    conn: &Connection,
+    role: Option<&str>,
+    exclude_id: Option<i64>,
+) -> rusqlite::Result<Option<String>> {
+    let Some(r) = role else {
+        return Ok(None);
+    };
+    let taken: bool = conn.query_row(
+        "SELECT EXISTS(SELECT 1 FROM mailboxes WHERE role = ?1 AND (?2 IS NULL OR id != ?2))",
+        params![r, exclude_id],
+        |row| row.get(0),
+    )?;
+    Ok((!taken).then(|| r.to_owned()))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::db::init;
+
+    fn mem() -> Connection {
+        let conn = Connection::open_in_memory().unwrap();
+        init::apply_schema(&conn).unwrap();
+        conn
+    }
+
+    fn insert(conn: &Connection, name: &str, role: Option<&str>) -> i64 {
+        conn.execute(
+            "INSERT INTO mailboxes (name, parent_id, role, sort_order, is_subscribed)
+             VALUES (?1, NULL, ?2, 0, 1)",
+            params![name, role],
+        )
+        .unwrap();
+        conn.last_insert_rowid()
+    }
+
+    #[test]
+    fn first_claimant_keeps_role_second_is_dropped() {
+        let conn = mem();
+        let first = unique_role(&conn, Some("sent"), None).unwrap();
+        assert_eq!(first.as_deref(), Some("sent"));
+        insert(&conn, "Sent", first.as_deref());
+
+        let second = unique_role(&conn, Some("sent"), None).unwrap();
+        assert_eq!(second, None);
+    }
+
+    #[test]
+    fn null_role_stays_null() {
+        let conn = mem();
+        assert_eq!(unique_role(&conn, None, None).unwrap(), None);
+    }
+
+    #[test]
+    fn distinct_roles_are_independent() {
+        let conn = mem();
+        insert(&conn, "Sent", Some("sent"));
+        assert_eq!(
+            unique_role(&conn, Some("trash"), None).unwrap().as_deref(),
+            Some("trash")
+        );
+    }
+
+    #[test]
+    fn update_excludes_own_row() {
+        let conn = mem();
+        let id = insert(&conn, "Sent", Some("sent"));
+        assert_eq!(
+            unique_role(&conn, Some("sent"), Some(id)).unwrap().as_deref(),
+            Some("sent")
+        );
+    }
+
+    #[test]
+    fn update_detects_other_holder() {
+        let conn = mem();
+        insert(&conn, "Sent", Some("sent"));
+        let other = insert(&conn, "Envoyés", None);
+        assert_eq!(unique_role(&conn, Some("sent"), Some(other)).unwrap(), None);
+    }
+}