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// Copyright 2016-2020 the Tectonic Project
// Licensed under the MIT License.
//! Tectonic error types and support code.
// Silence warnings due to `error-chain` using `Error::cause` instead of `Error::source`. The
// former was [deprecated in Rust 1.33](https://github.com/rust-lang/rust/pull/53533). The fix for
// `error-chain` is in <https://github.com/rust-lang-nursery/error-chain/pull/255> and will
// hopefully show up in a future version.
#![allow(deprecated)]
use error_chain::error_chain;
use std::{
convert, ffi,
fmt::{self, Debug, Display},
io,
io::Write,
num,
result::Result as StdResult,
str,
sync::{Arc, Mutex, Weak},
};
use tectonic_errors::Error as NewError;
use zip::result::ZipError;
cfg_if::cfg_if! {
if #[cfg(feature = "toml")] {
pub type ReadError = toml::de::Error;
pub type WriteError = toml::ser::Error;
} else {
use std::error;
#[derive(Debug)]
pub enum ReadError {}
impl Display for ReadError {
fn fmt(&self, _fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
Ok(())
}
}
impl error::Error for ReadError { }
#[derive(Debug)]
pub enum WriteError {}
impl Display for WriteError {
fn fmt(&self, _fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
Ok(())
}
}
impl error::Error for WriteError { }
}
}
error_chain! {
types {
Error, ErrorKind, ResultExt, Result;
}
foreign_links {
Io(io::Error);
Fmt(fmt::Error);
Nul(ffi::NulError);
ParseInt(num::ParseIntError);
Persist(tempfile::PersistError);
ConfigRead(ReadError);
ConfigWrite(WriteError);
NewStyle(NewError);
QuickXml(quick_xml::Error);
Time(std::time::SystemTimeError);
Utf8(str::Utf8Error);
Xdv(tectonic_xdv::XdvError);
Zip(ZipError);
}
errors {
BadLength(expected: usize, observed: usize) {
description("the item is not the expected length")
display("expected length {}; found {}", expected, observed)
}
NotSeekable {
description("this stream is not seekable")
display("this stream is not seekable")
}
NotSizeable {
description("the size of this stream cannot be determined")
display("the size of this stream cannot be determined")
}
PathForbidden(path: String) {
description("access to this file path is forbidden")
display("access to the path {} is forbidden", path)
}
EngineError(engine: &'static str) {
description("some engine had an unrecoverable error")
display("the {} engine had an unrecoverable error", engine)
}
}
}
/// `chain_err` compatibility between our old and new error types
pub trait ChainErrCompatExt<T> {
fn chain_err<F, K>(self, chainer: F) -> Result<T>
where
F: FnOnce() -> K,
K: Into<ErrorKind>;
}
impl<T> ChainErrCompatExt<T> for StdResult<T, NewError> {
fn chain_err<F, K>(self, chainer: F) -> Result<T>
where
F: FnOnce() -> K,
K: Into<ErrorKind>,
{
self.map_err(|e| {
let e: Error = e.into();
e.chain_err(chainer)
})
}
}
/// Use string formatting to create an `Error` of kind
/// `errors::ErrorKind::Msg`.
#[macro_export]
macro_rules! errmsg {
($( $fmt_args:expr ),*) => {
$crate::errors::ErrorKind::Msg(format!($( $fmt_args ),*)).into()
};
}
/// “Chained try” — like `try!`, but with the ability to add context to the error message.
#[macro_export]
macro_rules! ctry {
($op:expr ; $( $chain_fmt_args:expr ),*) => {{
#[allow(unused_imports)]
use $crate::errors::{ChainErrCompatExt, ResultExt};
$op.chain_err(|| format!($( $chain_fmt_args ),*))?
}}
}
impl convert::From<Error> for io::Error {
fn from(err: Error) -> io::Error {
io::Error::new(io::ErrorKind::Other, format!("{err}"))
}
}
impl Error {
/// Write the information contained in this object to standard error in a
/// somewhat user-friendly form.
///
/// The `error_chain` crate provides a Display impl for its Error objects
/// that ought to provide this functionality, but I have had enormous
/// trouble being able to use it. So instead we emulate their code. This
/// function is also paralleled by the implementation in
/// `status::termcolor::TermcolorStatusBackend`, which adds the sugar of
/// providing nice colorization if possible. This function should only be
/// used if a `StatusBackend` is not yet available in the running program.
pub fn dump_uncolorized(&self) {
let mut prefix = "error:";
let mut s = io::stderr();
for item in self.iter() {
writeln!(s, "{prefix} {item}").expect("write to stderr failed");
prefix = "caused by:";
}
if let Some(backtrace) = self.backtrace() {
writeln!(s, "debugging: backtrace follows:").expect("write to stderr failed");
writeln!(s, "{backtrace:?}").expect("write to stderr failed");
}
}
}
/// The DefinitelySame trait is a helper trait implemented because Errors do
/// not generically implement PartialEq. This is a bit of a drag for testing
/// since it's nice to be able to check if an error matches the one that's
/// expected. DefinitelySame addresses this by providing a weak equivalence
/// test: definitely_same() returns true if the two values definitely are
/// equivalent, and false otherwise. This can happen if the value are known to
/// be different, but also if we can't tell. It doesn't cover all cases, but
/// it does cover the ones that come up in our test suite.
pub trait DefinitelySame {
fn definitely_same(&self, other: &Self) -> bool;
}
// Rust currently thinks that this impl conflicts with the one that we
// provide for Result ... I am pretty sure that's not the case since the
// Result PartialEq impl requires that T and E be PartialEq too, whereas
// our definition works for subtypes that are DefinitelySame but
// not PartialEq too.
//
//impl<T: PartialEq> DefinitelySame for T {
// fn definitely_same(&self, other: &T) -> bool {
// self == other
// }
//}
impl DefinitelySame for ErrorKind {
fn definitely_same(&self, other: &Self) -> bool {
match self {
ErrorKind::Msg(ref s) => {
if let ErrorKind::Msg(ref o) = *other {
s == o
} else {
false
}
}
// Hacky for tex-outputs test
ErrorKind::NewStyle(ref s) => {
if let ErrorKind::NewStyle(ref o) = *other {
s.to_string() == o.to_string()
} else {
false
}
}
_ => false,
}
}
}
impl DefinitelySame for NewError {
/// Hack alert! We only compare stringifications.
fn definitely_same(&self, other: &Self) -> bool {
self.to_string() == other.to_string()
}
}
impl<T: DefinitelySame, E: DefinitelySame> DefinitelySame for StdResult<T, E> {
fn definitely_same(&self, other: &Self) -> bool {
match *self {
Ok(ref st) => {
if let Ok(ref ot) = *other {
st.definitely_same(ot)
} else {
false
}
}
Err(ref se) => {
if let Err(ref oe) = *other {
se.definitely_same(oe)
} else {
false
}
}
}
}
}
// SyncError copied from:
// https://github.com/rust-lang-nursery/error-chain/issues/240
//
// This is needed to be able to turn error_chain errors into anyhow errors,
// since the latter requires that they are sync.
pub struct SyncError<T: 'static> {
inner: Arc<Mutex<T>>,
proxy: Option<CauseProxy<T>>,
}
impl<T: std::error::Error + 'static> SyncError<T> {
pub fn new(err: T) -> Self {
let arc = Arc::new(Mutex::new(err));
let proxy = arc
.lock()
.unwrap()
.source()
.map(|s| CauseProxy::new(s, Arc::downgrade(&arc), 0));
SyncError { inner: arc, proxy }
}
pub fn maybe<R>(r: std::result::Result<R, T>) -> std::result::Result<R, Self> {
match r {
Ok(v) => Ok(v),
Err(e) => Err(SyncError::new(e)),
}
}
pub fn unwrap(self) -> T {
Arc::try_unwrap(self.inner).unwrap().into_inner().unwrap()
}
}
impl<T: std::error::Error + 'static> std::error::Error for SyncError<T> {
#[cfg(backtrace)]
fn backtrace(&self) -> Option<&Backtrace> {}
fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
self.proxy.as_ref().map(|e| e as _)
}
}
impl<T> Display for SyncError<T>
where
T: Display,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
self.inner.lock().unwrap().fmt(f)
}
}
impl<T> Debug for SyncError<T>
where
T: Debug,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
self.inner.lock().unwrap().fmt(f)
}
}
struct CauseProxy<T: 'static> {
inner: Weak<Mutex<T>>,
next: Option<Box<CauseProxy<T>>>,
depth: u32,
}
impl<T: std::error::Error> CauseProxy<T> {
fn new(err: &dyn std::error::Error, weak: Weak<Mutex<T>>, depth: u32) -> Self {
// Can't allocate an object, or mutate the proxy safely during source(),
// so we just take the hit at construction, recursively. We can't hold
// references outside the mutex at all, so instead we remember how many
// steps to get to this proxy. And if some error chain plays tricks, the
// user gets both pieces.
CauseProxy {
inner: weak.clone(),
depth,
next: err
.source()
.map(|s| Box::new(CauseProxy::new(s, weak, depth + 1))),
}
}
fn with_instance<R, F>(&self, f: F) -> R
where
F: FnOnce(&(dyn std::error::Error + 'static)) -> R,
{
let arc = self.inner.upgrade().unwrap();
{
let e = arc.lock().unwrap();
let mut source = e.source().unwrap();
for _ in 0..self.depth {
source = source.source().unwrap();
}
f(source)
}
}
}
impl<T: std::error::Error + 'static> std::error::Error for CauseProxy<T> {
#[cfg(backtrace)]
fn backtrace(&self) -> Option<&Backtrace> {}
fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
self.next.as_ref().map(|e| e as _)
}
}
impl<T> Display for CauseProxy<T>
where
T: Display + std::error::Error,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
self.with_instance(|i| std::fmt::Display::fmt(&i, f))
}
}
impl<T> Debug for CauseProxy<T>
where
T: Debug + std::error::Error,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
self.with_instance(|i| std::fmt::Debug::fmt(&i, f))
}
}