Handle maximum table name length (#37)

* Handle maximum table name length

* bump patch (#46)

* bump patch

* Update Cargo.toml

* Add a test for checking max. table identifier length

---------

Co-authored-by: Adam Hendel <[email protected]>

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "pgmq"
-version = "0.12.0"
+version = "0.12.1"
 edition = "2021"
 authors = ["Tembo.io"]
 description = "Postgres extension for PGMQ"

core/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "pgmq"
-version = "0.15.0"
+version = "0.15.1"
 edition = "2021"
 authors = ["Tembo.io"]
 description = "A distributed message queue for Rust applications, on Postgres."

core/src/query.rs

@@ -299,10 +299,23 @@ pub fn pop(name: &str) -> Result<String, PgmqError> {
 
 /// panics if input is invalid. otherwise does nothing.
 pub fn check_input(input: &str) -> Result<(), PgmqError> {
-    let valid = input
+    // Docs:
+    // https://www.postgresql.org/docs/current/sql-syntax-lexical.html#SQL-SYNTAX-IDENTIFIERS
+
+    // Default value of `NAMEDATALEN`, set in `src/include/pg_config_manual.h`
+    const NAMEDATALEN: usize = 64;
+    // The maximum length of an identifier.
+    // Longer names can be used in commands, but they'll be truncated
+    const MAX_IDENTIFIER_LEN: usize = NAMEDATALEN - 1;
+    // The max length of a PGMQ table, considering its prefix and the underline after it (e.g. "pgmq_")
+    const MAX_PGMQ_TABLE_LEN: usize = MAX_IDENTIFIER_LEN - TABLE_PREFIX.len() - 1;
+
+    let is_short_enough = input.len() <= MAX_PGMQ_TABLE_LEN;
+    let has_valid_characters = input
         .as_bytes()
         .iter()
         .all(|&c| c.is_ascii_alphanumeric() || c == b'_');
+    let valid = is_short_enough && has_valid_characters;
     match valid {
         true => Ok(()),
         false => Err(PgmqError::InvalidQueueName {
@@ -373,6 +386,18 @@ mod tests {
         }
     }
 
+    #[test]
+    fn check_input_rejects_names_too_large() {
+        let table_name = "my_valid_table_name";
+        assert!(check_input(table_name).is_ok());
+
+        assert!(check_input(&"a".repeat(58)).is_ok());
+
+        assert!(check_input(&"a".repeat(59)).is_err());
+        assert!(check_input(&"a".repeat(60)).is_err());
+        assert!(check_input(&"a".repeat(70)).is_err());
+    }
+
     #[test]
     fn test_check_input() {
         let invalids = vec!["bad;queue_name", "bad name", "bad--name"];