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use odbc_sys::SqlReturn;
/// Result of an ODBC function call. Variants hold the same meaning as the constants associated with
/// [`SqlReturn`]. This type may hold results, but it is still the responsibility of the user to
/// fetch and handle the diagnostics in case of an Error.
#[derive(Debug, PartialEq, Eq, Clone, Copy)]
pub enum SqlResult<T> {
/// The function has been executed successfully.
Success(T),
/// The function has been executed successfully. There have been warnings.
SuccessWithInfo(T),
/// The function was started asynchronously and is still executing.
StillExecuting,
/// The function returned an error state. Check diagnostics.
Error {
/// Name of the ODBC Api call which caused the error. This might help interpreting
/// associatedif the error ODBC diagnostics if the error is bubbeld all the way up to the
/// end users output, but the context is lost.
function: &'static str,
},
}
impl SqlResult<()> {
/// Append a return value a successful to Result
pub fn on_success<F, T>(self, f: F) -> SqlResult<T>
where
F: FnOnce() -> T,
{
self.map(|()| f())
}
}
impl<T> SqlResult<T> {
/// `True` if variant is [`SqlResult::Error`].
pub fn is_err(&self) -> bool {
matches!(self, SqlResult::Error { .. })
}
/// Applies `f` to any value wrapped in `Success` or `SuccessWithInfo`.
pub fn map<U, F>(self, f: F) -> SqlResult<U>
where
F: FnOnce(T) -> U,
{
match self {
SqlResult::Success(v) => SqlResult::Success(f(v)),
SqlResult::SuccessWithInfo(v) => SqlResult::SuccessWithInfo(f(v)),
SqlResult::Error { function } => SqlResult::Error { function },
SqlResult::StillExecuting => SqlResult::StillExecuting,
}
}
pub fn unwrap(self) -> T {
match self {
SqlResult::Success(v) | SqlResult::SuccessWithInfo(v) => v,
SqlResult::Error { .. } => panic!("Unwraping SqlResult::Error"),
SqlResult::StillExecuting => panic!("Unwraping SqlResult::StillExecuting"),
}
}
}
pub trait ExtSqlReturn {
fn into_sql_result(self, function_name: &'static str) -> SqlResult<()>;
/// Use this instead of [`Self::into_sql_result`] if you expect [`SqlReturn::NO_DATA`] to be a
/// valid value. [`SqlReturn::NO_DATA`] is mapped to `Ok(false)`, all other success values are
/// `Ok(true)`.
fn into_sql_result_bool(self, function_name: &'static str) -> SqlResult<bool>;
}
impl ExtSqlReturn for SqlReturn {
fn into_sql_result(self, function: &'static str) -> SqlResult<()> {
match self {
SqlReturn::SUCCESS => SqlResult::Success(()),
SqlReturn::SUCCESS_WITH_INFO => SqlResult::SuccessWithInfo(()),
SqlReturn::ERROR => SqlResult::Error { function },
SqlReturn::STILL_EXECUTING => SqlResult::StillExecuting,
r => panic!(
"Unexpected return value '{:?}' for ODBC function '{}'",
r, function
),
}
}
fn into_sql_result_bool(self, function: &'static str) -> SqlResult<bool> {
match self {
SqlReturn::NO_DATA => SqlResult::Success(false),
other => other.into_sql_result(function).on_success(|| true),
}
}
}