#[derive(Debug, Clone, PartialEq, Eq)]
pub enum CommandTag {
Select(u64),
Insert(u64),
Update(u64),
Delete(u64),
Create(String),
Drop(String),
Alter(String),
Truncate,
Begin,
Commit,
Rollback,
Other(String),
}
impl CommandTag {
pub fn is_data_modifying(&self) -> bool {
!matches!(self, Self::Select(_) | Self::Other(_))
}
pub fn is_schema_modifying(&self) -> bool {
matches!(self, Self::Create(_) | Self::Drop(_) | Self::Alter(_))
}
pub fn needs_refresh(&self) -> bool {
matches!(
self,
Self::Insert(_)
| Self::Update(_)
| Self::Delete(_)
| Self::Create(_)
| Self::Drop(_)
| Self::Alter(_)
| Self::Truncate
)
}
pub fn affected_rows(&self) -> Option<u64> {
match self {
Self::Select(n) | Self::Insert(n) | Self::Update(n) | Self::Delete(n) => Some(*n),
_ => None,
}
}
pub fn display_message(&self) -> String {
match self {
Self::Select(n) => row_count_label(*n, "selected"),
Self::Insert(n) => row_count_label(*n, "inserted"),
Self::Update(n) => row_count_label(*n, "updated"),
Self::Delete(n) => row_count_label(*n, "deleted"),
Self::Create(obj) => format!("{} created", obj.to_lowercase()),
Self::Drop(obj) => format!("{} dropped", obj.to_lowercase()),
Self::Alter(obj) => format!("{} altered", obj.to_lowercase()),
Self::Truncate => "table truncated".to_string(),
Self::Begin => "transaction started".to_string(),
Self::Commit => "committed".to_string(),
Self::Rollback => "rolled back".to_string(),
Self::Other(tag) => tag.to_lowercase(),
}
}
}
fn row_count_label(n: u64, verb: &str) -> String {
if n == 1 {
format!("1 row {}", verb)
} else {
format!("{} rows {}", n, verb)
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn affected_rows_returns_count_for_dml() {
assert_eq!(CommandTag::Select(5).affected_rows(), Some(5));
assert_eq!(CommandTag::Insert(3).affected_rows(), Some(3));
assert_eq!(CommandTag::Update(1).affected_rows(), Some(1));
assert_eq!(CommandTag::Delete(0).affected_rows(), Some(0));
}
#[test]
fn affected_rows_returns_none_for_ddl_and_tcl() {
assert_eq!(
CommandTag::Create("TABLE".to_string()).affected_rows(),
None
);
assert_eq!(CommandTag::Drop("INDEX".to_string()).affected_rows(), None);
assert_eq!(CommandTag::Alter("TABLE".to_string()).affected_rows(), None);
assert_eq!(CommandTag::Truncate.affected_rows(), None);
assert_eq!(CommandTag::Begin.affected_rows(), None);
assert_eq!(CommandTag::Commit.affected_rows(), None);
assert_eq!(CommandTag::Rollback.affected_rows(), None);
}
#[test]
fn display_message_singular_row() {
assert_eq!(CommandTag::Insert(1).display_message(), "1 row inserted");
assert_eq!(CommandTag::Delete(1).display_message(), "1 row deleted");
}
#[test]
fn display_message_plural_rows() {
assert_eq!(CommandTag::Select(5).display_message(), "5 rows selected");
assert_eq!(CommandTag::Update(10).display_message(), "10 rows updated");
}
#[test]
fn display_message_zero_rows() {
assert_eq!(CommandTag::Delete(0).display_message(), "0 rows deleted");
}
#[test]
fn display_message_ddl() {
assert_eq!(
CommandTag::Create("TABLE".to_string()).display_message(),
"table created"
);
assert_eq!(
CommandTag::Drop("INDEX".to_string()).display_message(),
"index dropped"
);
assert_eq!(
CommandTag::Alter("TABLE".to_string()).display_message(),
"table altered"
);
}
#[test]
fn display_message_tcl() {
assert_eq!(CommandTag::Truncate.display_message(), "table truncated");
assert_eq!(CommandTag::Begin.display_message(), "transaction started");
assert_eq!(CommandTag::Commit.display_message(), "committed");
assert_eq!(CommandTag::Rollback.display_message(), "rolled back");
}
#[test]
fn display_message_other() {
assert_eq!(
CommandTag::Other("VACUUM".to_string()).display_message(),
"vacuum"
);
}
#[test]
fn is_schema_modifying_true_for_ddl() {
assert!(CommandTag::Create("TABLE".to_string()).is_schema_modifying());
assert!(CommandTag::Drop("TABLE".to_string()).is_schema_modifying());
assert!(CommandTag::Alter("TABLE".to_string()).is_schema_modifying());
}
#[test]
fn is_schema_modifying_false_for_non_ddl() {
assert!(!CommandTag::Select(0).is_schema_modifying());
assert!(!CommandTag::Insert(1).is_schema_modifying());
assert!(!CommandTag::Update(1).is_schema_modifying());
assert!(!CommandTag::Delete(1).is_schema_modifying());
assert!(!CommandTag::Truncate.is_schema_modifying());
assert!(!CommandTag::Begin.is_schema_modifying());
assert!(!CommandTag::Commit.is_schema_modifying());
assert!(!CommandTag::Rollback.is_schema_modifying());
assert!(!CommandTag::Other("VACUUM".to_string()).is_schema_modifying());
}
#[test]
fn needs_refresh_true_for_dml_and_ddl() {
assert!(CommandTag::Insert(1).needs_refresh());
assert!(CommandTag::Update(1).needs_refresh());
assert!(CommandTag::Delete(1).needs_refresh());
assert!(CommandTag::Create("TABLE".to_string()).needs_refresh());
assert!(CommandTag::Drop("TABLE".to_string()).needs_refresh());
assert!(CommandTag::Alter("TABLE".to_string()).needs_refresh());
assert!(CommandTag::Truncate.needs_refresh());
}
#[test]
fn needs_refresh_false_for_read_only_and_tcl() {
assert!(!CommandTag::Select(5).needs_refresh());
assert!(!CommandTag::Begin.needs_refresh());
assert!(!CommandTag::Commit.needs_refresh());
assert!(!CommandTag::Rollback.needs_refresh());
assert!(!CommandTag::Other("VACUUM".to_string()).needs_refresh());
}
}