124 lines
3.3 KiB
Rust
124 lines
3.3 KiB
Rust
#![doc = include_str!("../README.md")]
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#![forbid(unsafe_code)]
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#![cfg_attr(feature = "backtrace", feature(backtrace))]
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mod sealed;
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pub(crate) use sealed::seal;
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mod context;
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pub use context::{Context, IntoContext};
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mod report;
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use report::report_write;
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pub use report::{Report, ReportOpts};
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mod into;
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pub(crate) use into::IntoResultHow;
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mod explain;
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pub use explain::Explain;
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#[cfg(feature = "termination")]
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mod termination;
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#[cfg(feature = "termination")]
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pub use termination::TerminationResult;
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pub type Result<T, E = How> = std::result::Result<T, E>;
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/// Does not implement [`std::error::Error`] to allow a [`From`] implementation for all other error types.
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pub struct How(Box<HowInner>);
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struct HowInner {
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/// When true, the error will cause branchers to abort.
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classified: bool,
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// TODO: consider storing this vec inline (sharing the allocation with rest of the struct.
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// Probably move after `backtrace`)
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context: Vec<Context>,
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#[cfg(feature = "backtrace")]
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backtrace: std::backtrace::Backtrace,
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}
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impl std::fmt::Debug for How {
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fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
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let mut b = f.debug_struct(std::any::type_name::<Self>());
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let b = b
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.field("classified", &self.0.classified)
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.field("context", &self.0.context);
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#[cfg(feature = "backtrace")]
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let b = b.field("backtrace", &self.0.backtrace);
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b.finish()
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}
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}
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impl How {
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#[must_use]
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pub fn new(context: impl IntoContext) -> Self {
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Self(Box::new(HowInner {
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classified: false,
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context: {
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let mut vec = Vec::with_capacity(2);
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vec.push(context.into_context());
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vec
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},
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#[cfg(feature = "backtrace")]
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backtrace: std::backtrace::Backtrace::capture(),
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}))
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}
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#[must_use]
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pub fn clone_without_backtrace(&self) -> Self {
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Self(Box::new(HowInner {
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classified: self.0.classified,
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context: self.0.context.clone(),
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#[cfg(feature = "backtrace")]
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backtrace: std::backtrace::Backtrace::disabled(),
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}))
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}
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#[inline]
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#[must_use]
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pub fn classified(mut self) -> Self {
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self.0.classified = true;
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self
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}
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#[inline]
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#[must_use]
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pub const fn is_classified(&self) -> bool {
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self.0.classified
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}
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}
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impl explain::Sealed for How {}
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impl Explain for How {
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type Output = Self;
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#[inline]
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#[must_use]
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fn context(mut self, context: impl IntoContext) -> Self {
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self.0.context.push(context.into_context());
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self
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}
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}
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impl std::fmt::Display for How {
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fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
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let mut opts = ReportOpts::default();
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let mut ctxs = self.0.context.iter().rev();
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let ctx = ctxs.next().expect("`How` created with no context.");
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report_write!(f, &opts, "{ctx}")?;
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for ctx in ctxs {
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report_write!(f, &opts, "\n└ ")?;
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report_write!(f, &opts.indent().next(), "{ctx}")?;
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opts = opts.indent();
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}
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#[cfg(feature = "backtrace")]
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{
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opts = opts.indent();
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report_write!(f, &opts, "\n{}", self.0.backtrace)?;
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}
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Ok(())
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}
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}
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