imag/libimagerror/src/error_gen.rs

395 lines
11 KiB
Rust

use into::IntoError;
#[macro_export]
macro_rules! generate_error_imports {
() => {
use std::error::Error;
use std::fmt::Error as FmtError;
use std::fmt::{Display, Formatter};
use $crate::into::IntoError;
}
}
#[macro_export]
macro_rules! generate_error_module {
( $exprs:item ) => {
pub mod error {
generate_error_imports!();
$exprs
}
}
}
#[macro_export]
macro_rules! generate_custom_error_types {
{
$name: ident,
$kindname: ident,
$customMemberTypeName: ident,
$($kind:ident => $string:expr),*
} => {
#[derive(Clone, Copy, Debug, PartialEq)]
pub enum $kindname {
$( $kind ),*
}
impl Display for $kindname {
fn fmt(&self, fmt: &mut Formatter) -> Result<(), FmtError> {
let s = match *self {
$( $kindname::$kind => $string ),*
};
try!(write!(fmt, "{}", s));
Ok(())
}
}
impl IntoError for $kindname {
type Target = $name;
fn into_error(self) -> Self::Target {
$name::new(self, None)
}
fn into_error_with_cause(self, cause: Box<Error>) -> Self::Target {
$name::new(self, Some(cause))
}
}
#[derive(Debug)]
pub struct $name {
err_type: $kindname,
cause: Option<Box<Error>>,
custom_data: Option<$customMemberTypeName>,
}
impl $name {
pub fn new(errtype: $kindname, cause: Option<Box<Error>>) -> $name {
$name {
err_type: errtype,
cause: cause,
custom_data: None,
}
}
pub fn err_type(&self) -> $kindname {
self.err_type
}
}
impl Into<$name> for $kindname {
fn into(self) -> $name {
$name::new(self, None)
}
}
impl Display for $name {
fn fmt(&self, fmt: &mut Formatter) -> Result<(), FmtError> {
try!(write!(fmt, "[{}]", self.err_type));
Ok(())
}
}
impl Error for $name {
fn description(&self) -> &str {
match self.err_type {
$( $kindname::$kind => $string ),*
}
}
fn cause(&self) -> Option<&Error> {
self.cause.as_ref().map(|e| &**e)
}
}
}
}
#[macro_export]
macro_rules! generate_result_helper {
(
$name: ident,
$kindname: ident
) => {
/// Trait to replace
///
/// ```ignore
/// foo.map_err(Box::new).map_err(|e| SomeType::SomeErrorKind.into_error_with_cause(e))
/// // or:
/// foo.map_err(|e| SomeType::SomeErrorKind.into_error_with_cause(Box::new(e)))
/// ```
///
/// with much nicer
///
/// ```ignore
/// foo.map_err_into(SomeType::SomeErrorKind)
/// ```
///
pub trait MapErrInto<T> {
fn map_err_into(self, error_kind: $kindname) -> Result<T, $name>;
}
impl<T, E: Error + 'static> MapErrInto<T> for Result<T, E> {
fn map_err_into(self, error_kind: $kindname) -> Result<T, $name> {
self.map_err(Box::new)
.map_err(|e| error_kind.into_error_with_cause(e))
}
}
}
}
#[macro_export]
macro_rules! generate_option_helper {
(
$name: ident,
$kindname: ident
) => {
/// Trait to replace
///
/// ```ignore
/// foo.ok_or(SomeType::SomeErrorKind.into_error())
/// ```
///
/// with
///
/// ```ignore
/// foo.ok_or_errkind(SomeType::SomeErrorKind)
/// ```
pub trait OkOrErr<T> {
fn ok_or_errkind(self, kind: $kindname) -> Result<T, $name>;
}
impl<T> OkOrErr<T> for Option<T> {
fn ok_or_errkind(self, kind: $kindname) -> Result<T, $name> {
self.ok_or(kind.into_error())
}
}
}
}
#[macro_export]
macro_rules! generate_error_types {
(
$name: ident,
$kindname: ident,
$($kind:ident => $string:expr),*
) => {
#[derive(Debug, Clone, Eq, PartialEq, Ord, PartialOrd, Copy)]
pub struct SomeNotExistingTypeWithATypeNameNoOneWillEverChoose {}
generate_custom_error_types!($name, $kindname,
SomeNotExistingTypeWithATypeNameNoOneWillEverChoose,
$($kind => $string),*);
generate_result_helper!($name, $kindname);
generate_option_helper!($name, $kindname);
}
}
#[cfg(test)]
mod test {
generate_error_module!(
generate_error_types!(TestError, TestErrorKind,
TestErrorKindA => "testerrorkind a",
TestErrorKindB => "testerrorkind B");
);
#[derive(Debug, Clone, Eq, PartialEq, Ord, PartialOrd, Copy)]
pub struct CustomData {
pub test: i32,
pub othr: i64,
}
generate_error_imports!();
generate_custom_error_types!(CustomTestError, CustomTestErrorKind,
CustomData,
CustomErrorKindA => "customerrorkind a",
CustomErrorKindB => "customerrorkind B");
impl CustomTestError {
pub fn test(&self) -> i32 {
match self.custom_data {
Some(t) => t.test,
None => 0,
}
}
pub fn bar(&self) -> i64 {
match self.custom_data {
Some(t) => t.othr,
None => 0,
}
}
}
#[test]
fn test_a() {
use self::error::{TestError, TestErrorKind};
let kind = TestErrorKind::TestErrorKindA;
assert_eq!(String::from("testerrorkind a"), format!("{}", kind));
let e = TestError::new(kind, None);
assert_eq!(String::from("[testerrorkind a]"), format!("{}", e));
}
#[test]
fn test_b() {
use self::error::{TestError, TestErrorKind};
let kind = TestErrorKind::TestErrorKindB;
assert_eq!(String::from("testerrorkind B"), format!("{}", kind));
let e = TestError::new(kind, None);
assert_eq!(String::from("[testerrorkind B]"), format!("{}", e));
}
#[test]
fn test_ab() {
use std::error::Error;
use self::error::{TestError, TestErrorKind};
let kinda = TestErrorKind::TestErrorKindA;
let kindb = TestErrorKind::TestErrorKindB;
assert_eq!(String::from("testerrorkind a"), format!("{}", kinda));
assert_eq!(String::from("testerrorkind B"), format!("{}", kindb));
let e = TestError::new(kinda, Some(Box::new(TestError::new(kindb, None))));
assert_eq!(String::from("[testerrorkind a]"), format!("{}", e));
assert_eq!(TestErrorKind::TestErrorKindA, e.err_type());
assert_eq!(String::from("[testerrorkind B]"), format!("{}", e.cause().unwrap()));
}
pub mod anothererrormod {
generate_error_imports!();
generate_error_types!(TestError, TestErrorKind,
TestErrorKindA => "testerrorkind a",
TestErrorKindB => "testerrorkind B");
}
#[test]
fn test_other_a() {
use self::anothererrormod::{TestError, TestErrorKind};
let kind = TestErrorKind::TestErrorKindA;
assert_eq!(String::from("testerrorkind a"), format!("{}", kind));
let e = TestError::new(kind, None);
assert_eq!(String::from("[testerrorkind a]"), format!("{}", e));
}
#[test]
fn test_other_b() {
use self::anothererrormod::{TestError, TestErrorKind};
let kind = TestErrorKind::TestErrorKindB;
assert_eq!(String::from("testerrorkind B"), format!("{}", kind));
let e = TestError::new(kind, None);
assert_eq!(String::from("[testerrorkind B]"), format!("{}", e));
}
#[test]
fn test_other_ab() {
use std::error::Error;
use self::anothererrormod::{TestError, TestErrorKind};
let kinda = TestErrorKind::TestErrorKindA;
let kindb = TestErrorKind::TestErrorKindB;
assert_eq!(String::from("testerrorkind a"), format!("{}", kinda));
assert_eq!(String::from("testerrorkind B"), format!("{}", kindb));
let e = TestError::new(kinda, Some(Box::new(TestError::new(kindb, None))));
assert_eq!(String::from("[testerrorkind a]"), format!("{}", e));
assert_eq!(TestErrorKind::TestErrorKindA, e.err_type());
assert_eq!(String::from("[testerrorkind B]"), format!("{}", e.cause().unwrap()));
}
#[test]
fn test_error_kind_mapping() {
use std::io::{Error, ErrorKind};
use self::error::{OkOrErr, MapErrInto};
use self::error::TestErrorKind;
let err : Result<(), _> = Err(Error::new(ErrorKind::Other, ""));
let err : Result<(), _> = err.map_err_into(TestErrorKind::TestErrorKindA);
assert!(err.is_err());
let err = err.unwrap_err();
match err.err_type() {
TestErrorKind::TestErrorKindA => assert!(true),
_ => assert!(false),
}
}
#[test]
fn test_error_kind_double_mapping() {
use std::io::{Error, ErrorKind};
use self::error::{OkOrErr, MapErrInto};
use self::error::TestErrorKind;
let err : Result<(), _> = Err(Error::new(ErrorKind::Other, ""));
let err : Result<(), _> = err.map_err_into(TestErrorKind::TestErrorKindA)
.map_err_into(TestErrorKind::TestErrorKindB);
assert!(err.is_err());
let err = err.unwrap_err();
match err.err_type() {
TestErrorKind::TestErrorKindB => assert!(true),
_ => assert!(false),
}
// not sure how to test that the inner error is of TestErrorKindA, actually...
match err.cause() {
Some(_) => assert!(true),
None => assert!(false),
}
}
#[test]
fn test_error_option_good() {
use self::error::{OkOrErr, MapErrInto};
use self::error::TestErrorKind;
let something = Some(1);
match something.ok_or_errkind(TestErrorKind::TestErrorKindA) {
Ok(1) => assert!(true),
_ => assert!(false),
}
}
#[test]
fn test_error_option_bad() {
use self::error::{OkOrErr, MapErrInto};
use self::error::TestErrorKind;
let something : Option<i32> = None;
match something.ok_or_errkind(TestErrorKind::TestErrorKindA) {
Ok(_) => assert!(false),
Err(e) => assert!(true),
}
}
}