wiwi_err/

lib.rs

pub use core::error::Error as ErrorTrait;
use core::panic::Location;
use core::fmt::{ self, Debug, Display };

pub mod prelude;
#[cfg(feature = "axum-0-8")]
mod axum_0_8;

pub struct Err<E> {
	// use box to make stack size smaller
	frame: Box<TypedFrame<E>>
}

impl<E> Err<E>
where
	E: ErrorTrait + Send + Sync + 'static
{
	#[inline]
	#[track_caller]
	pub fn from_err(err: E) -> Self {
		let children = walk(&err);

		Err {
			frame: Box::new(TypedFrame {
				err,
				location: Location::caller(),
				children
			})
		}
	}

	#[inline]
	#[track_caller]
	pub fn from_errs<C>(err: E, children: &mut dyn Iterator<Item = C>) -> Self
	where
		C: ErrorTrait + Send + Sync + 'static
	{
		let (len, _) = children.size_hint();
		let mut processed_children = Vec::with_capacity(len);
		for err in children {
			let children = walk(&err);

			processed_children.push(Frame {
				err: Box::new(err),
				location: Location::caller(),
				children
			});
		}

		Err {
			frame: Box::new(TypedFrame {
				err,
				location: Location::caller(),
				children: processed_children
			})
		}
	}

	#[inline]
	#[track_caller]
	pub fn raise<E2>(self, err: E2) -> Err<E2>
	where
		E2: ErrorTrait + Send + Sync + 'static
	{
		let mut new = Err::from_err(err);
		new.frame.children.push((*self.frame).into());
		new
	}

	#[inline]
	pub fn as_inner(&self) -> &E {
		&self.frame.err
	}

	#[inline]
	pub fn simple_display(&self) -> SimpleDisplay<'_, E> {
		SimpleDisplay { inner: self }
	}

	#[inline]
	pub fn detailed_display(&self) -> DetailedDisplay<'_, E> {
		DetailedDisplay { inner: self }
	}

	#[inline]
	pub fn as_error(&self) -> ErrorImplementorBorrowed<'_, E> {
		ErrorImplementorBorrowed { inner: self }
	}

	#[inline]
	pub fn into_error(self) -> ErrorImplementorOwned<E> {
		ErrorImplementorOwned { inner: self }
	}
}

impl<E> Debug for Err<E>
where
	E: ErrorTrait + Send + Sync + 'static
{
	#[inline]
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		self.detailed_display().fmt(f)
	}
}

struct TypedFrame<E> {
	err: E,
	location: &'static Location<'static>,
	children: Vec<Frame>
}

struct Frame {
	err: Box<dyn ErrorTrait + Send + Sync + 'static>,
	location: &'static Location<'static>,
	children: Vec<Frame>
}

impl<E> From<TypedFrame<E>> for Frame
where
	E: ErrorTrait + Send + Sync + 'static
{
	#[inline]
	fn from(frame: TypedFrame<E>) -> Self {
		let TypedFrame { err, location, children } = frame;
		let err = Box::new(err);
		Frame { err, location, children }
	}
}

struct BorrowedFrame<'h> {
	err: &'h (dyn ErrorTrait + Send + Sync + 'static),
	location: &'static Location<'static>,
	children: &'h [Frame]
}

impl<'h, E> From<&'h TypedFrame<E>> for BorrowedFrame<'h>
where
	E: ErrorTrait + Send + Sync + 'static
{
	#[inline]
	fn from(frame: &'h TypedFrame<E>) -> Self {
		let TypedFrame { err, location, children } = frame;
		Self { err, location, children }
	}
}

impl<'h> From<&'h Frame> for BorrowedFrame<'h> {
	#[inline]
	fn from(frame: &'h Frame) -> Self {
		let Frame { err, location, children } = frame;
		Self { err: &**err, location, children }
	}
}

pub struct SimpleDisplay<'h, E> {
	inner: &'h Err<E>
}

impl<'h, E> Display for SimpleDisplay<'h, E>
where
	E: ErrorTrait + Send + Sync + 'static
{
	#[inline]
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		Display::fmt(&self.inner.frame.err, f)
	}
}

pub struct DetailedDisplay<'h, E> {
	inner: &'h Err<E>
}

impl<'h, E> Display for DetailedDisplay<'h, E>
where
	E: ErrorTrait + Send + Sync + 'static
{
	#[inline]
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		print_err_dbg(
			f,
			(&*self.inner.frame).into(),
			0,
			&mut String::new()
		)
	}
}

pub struct ErrorImplementorBorrowed<'h, E> {
	inner: &'h Err<E>
}

impl<'h, E> ErrorImplementorBorrowed<'h, E> {
	#[inline]
	pub fn as_err(&self) -> &Err<E> {
		self.inner
	}
}

impl<'h, E> Debug for ErrorImplementorBorrowed<'h, E>
where
	E: ErrorTrait + Send + Sync + 'static
{
	#[inline]
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		self.inner.detailed_display().fmt(f)
	}
}

impl<'h, E> Display for ErrorImplementorBorrowed<'h, E>
where
	E: ErrorTrait + Send + Sync + 'static
{
	#[inline]
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		self.inner.simple_display().fmt(f)
	}
}

impl<'h, E> ErrorTrait for ErrorImplementorBorrowed<'h, E>
where
	E: ErrorTrait + Send + Sync + 'static
{}

pub struct ErrorImplementorOwned<E> {
	inner: Err<E>
}

impl<E> ErrorImplementorOwned<E> {
	#[inline]
	pub fn as_err(&self) -> &Err<E> {
		&self.inner
	}

	#[inline]
	pub fn into_err(self) -> Err<E> {
		self.inner
	}
}

impl<E> Debug for ErrorImplementorOwned<E>
where
	E: ErrorTrait + Send + Sync + 'static
{
	#[inline]
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		self.inner.detailed_display().fmt(f)
	}
}

impl<E> Display for ErrorImplementorOwned<E>
where
	E: ErrorTrait + Send + Sync + 'static
{
	#[inline]
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		self.inner.simple_display().fmt(f)
	}
}

impl<E> ErrorTrait for ErrorImplementorOwned<E>
where
	E: ErrorTrait + Send + Sync + 'static
{}

struct StringError {
	debug: Box<str>,
	display: Box<str>
}

impl Debug for StringError {
	#[inline]
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		f.write_str(&self.debug)
	}
}

impl Display for StringError {
	#[inline]
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		f.write_str(&self.display)
	}
}

impl ErrorTrait for StringError {}

#[track_caller]
fn walk(err: &dyn ErrorTrait) -> Vec<Frame> {
	if let Some(err) = err.source() {
		vec![Frame {
			err: Box::new(StringError {
				debug: format!("{err:?}").into_boxed_str(),
				display: format!("{err}").into_boxed_str()
			}),
			location: Location::caller(),
			children: walk(err)
		}]
	} else {
		Vec::new()
	}
}

fn print_err_dbg(
	f: &mut fmt::Formatter<'_>,
	frame: BorrowedFrame<'_>,
	level: usize,
	prefix_buf: &mut String
) -> fmt::Result {
	let prefix_buf_len = prefix_buf.len();
	let level_in_spaces = level * 2;
	if prefix_buf_len < level_in_spaces {
		let additional = level_in_spaces - prefix_buf_len;

		prefix_buf.reserve(additional);
		(0..additional).for_each(|_| prefix_buf.push(' '));
	}
	let prefix = &prefix_buf[..level_in_spaces];

	write!(
		f,
		"{prefix}- err in {file}, at {line}:{col}",
		file = frame.location.file(),
		line = frame.location.line(),
		col = frame.location.column()
	)?;

	write!(f, "\n{prefix}  {}", frame.err)?;

	if !frame.children.is_empty() {
		write!(f, "\n{prefix}  caused by:")?;
	}

	for child in frame.children {
		writeln!(f)?;
		print_err_dbg(f, child.into(), level + 1, prefix_buf)?;
	}

	Ok(())
}

pub trait ErrorExt {
	fn raise(self) -> Err<Self>
	where
		Self: Sized;
}

impl<E> ErrorExt for E
where
	E: ErrorTrait + Send + Sync + 'static
{
	#[inline]
	#[track_caller]
	fn raise(self) -> Err<Self> {
		Err::from_err(self)
	}
}

pub trait OptionExt {
	type Ok;

	fn or_raise<E>(self, err: impl FnOnce() -> E) -> Result<Self::Ok, Err<E>>
	where
		E: ErrorTrait + Send + Sync + 'static;
}

impl<T> OptionExt for Option<T> {
	type Ok = T;

	#[inline]
	#[track_caller]
	fn or_raise<E>(self, err: impl FnOnce() -> E) -> Result<T, Err<E>>
	where
		E: ErrorTrait + Send + Sync + 'static
	{
		match self {
			Some(value) => { Ok(value) }
			None => { Err(Err::from_err(err())) }
		}
	}
}

pub trait ResultExt {
	type Ok;
	type Err;

	fn or_raise<E>(self, err: impl FnOnce() -> E) -> Result<Self::Ok, Err<E>>
	where
		E: ErrorTrait + Send + Sync + 'static;
}

impl<T, E> ResultExt for Result<T, E>
where
	E: ErrorTrait + Send + Sync + 'static
{
	type Ok = T;
	type Err = E;

	#[inline]
	#[track_caller]
	fn or_raise<E2>(self, err: impl FnOnce() -> E2) -> Result<T, Err<E2>>
	where
		E2: ErrorTrait + Send + Sync + 'static
	{
		match self {
			Ok(value) => { Ok(value) }
			Err(prev_err) => { Err(Err::from_err(prev_err).raise(err())) }
		}
	}
}

impl<T, E> ResultExt for Result<T, Err<E>>
where
	E: ErrorTrait + Send + Sync + 'static
{
	type Ok = T;
	type Err = E;

	#[inline]
	#[track_caller]
	fn or_raise<E2>(self, err: impl FnOnce() -> E2) -> Result<T, Err<E2>>
	where
		E2: ErrorTrait + Send + Sync + 'static
	{
		match self {
			Ok(value) => { Ok(value) }
			Err(prev_err) => { Err(prev_err.raise(err())) }
		}
	}
}

pub trait ResultManyExt {
	type Ok;
	type Err;

	fn or_raise<E>(self, err: impl FnOnce() -> E) -> Result<Self::Ok, Err<E>>
	where
		E: ErrorTrait + Send + Sync + 'static;
}

impl<T, E> ResultManyExt for Result<T, Vec<E>>
where
	E: ErrorTrait + Send + Sync + 'static
{
	type Ok = T;
	type Err = E;

	#[inline]
	#[track_caller]
	fn or_raise<E2>(self, err: impl FnOnce() -> E2) -> Result<T, Err<E2>>
	where
		E2: ErrorTrait + Send + Sync + 'static
	{
		match self {
			Ok(value) => { Ok(value) }
			Err(errors) => { Err(Err::from_errs(err(), &mut errors.into_iter())) }
		}
	}
}

impl<T, E> ResultManyExt for Result<T, Vec<Err<E>>>
where
	E: ErrorTrait + Send + Sync + 'static
{
	type Ok = T;
	type Err = E;

	#[inline]
	#[track_caller]
	fn or_raise<E2>(self, err: impl FnOnce() -> E2) -> Result<T, Err<E2>>
	where
		E2: ErrorTrait + Send + Sync + 'static
	{
		match self {
			Ok(value) => { Ok(value) }
			Err(errors) => {
				let mut errors = errors
					.into_iter()
					.map(Err::into_error);

				Err(Err::from_errs(err(), &mut errors))
			}
		}
	}
}

impl<T, E> ResultManyExt for Result<T, &[E]>
where
	E: ErrorTrait + Clone + Send + Sync + 'static
{
	type Ok = T;
	type Err = E;

	#[inline]
	#[track_caller]
	fn or_raise<E2>(self, err: impl FnOnce() -> E2) -> Result<T, Err<E2>>
	where
		E2: ErrorTrait + Send + Sync + 'static
	{
		match self {
			Ok(value) => { Ok(value) }
			Err(errors) => { Err(Err::from_errs(err(), &mut errors.iter().cloned())) }
		}
	}
}

impl<T, E, const N: usize> ResultManyExt for Result<T, [E; N]>
where
	E: ErrorTrait + Send + Sync + 'static
{
	type Ok = T;
	type Err = E;

	#[inline]
	#[track_caller]
	fn or_raise<E2>(self, err: impl FnOnce() -> E2) -> Result<T, Err<E2>>
	where
		E2: ErrorTrait + Send + Sync + 'static
	{
		match self {
			Ok(value) => { Ok(value) }
			Err(errors) => { Err(Err::from_errs(err(), &mut errors.into_iter())) }
		}
	}
}

impl<T, E, const N: usize> ResultManyExt for Result<T, [Err<E>; N]>
where
	E: ErrorTrait + Send + Sync + 'static
{
	type Ok = T;
	type Err = E;

	#[inline]
	#[track_caller]
	fn or_raise<E2>(self, err: impl FnOnce() -> E2) -> Result<T, Err<E2>>
	where
		E2: ErrorTrait + Send + Sync + 'static
	{
		match self {
			Ok(value) => { Ok(value) }
			Err(errors) => {
				let mut errors = errors
					.into_iter()
					.map(Err::into_error);

				Err(Err::from_errs(err(), &mut errors))
			}
		}
	}
}

#[doc(hidden)]
pub mod __proc_macro_support {
	pub use core::error::Error;
	pub use core::fmt::{ Debug, Display };
	pub use displaydoc::Display;
}