Revision control
Copy as Markdown
Other Tools
use crate::util::{
primitives::{PatternID, SmallIndex},
search::MatchKind,
};
/// An error that occurred during the construction of an Aho-Corasick
/// automaton.
///
/// Build errors occur when some kind of limit has been exceeded, either in the
/// number of states, the number of patterns of the length of a pattern. These
/// limits aren't part of the public API, but they should generally be large
/// enough to handle most use cases.
///
/// When the `std` feature is enabled, this implements the `std::error::Error`
/// trait.
#[derive(Clone, Debug)]
pub struct BuildError {
kind: ErrorKind,
}
/// The kind of error that occurred.
#[derive(Clone, Debug)]
enum ErrorKind {
/// An error that occurs when allocating a new state would result in an
/// identifier that exceeds the capacity of a `StateID`.
StateIDOverflow {
/// The maximum possible id.
max: u64,
/// The maximum ID requested.
requested_max: u64,
},
/// An error that occurs when adding a pattern to an Aho-Corasick
/// automaton would result in an identifier that exceeds the capacity of a
/// `PatternID`.
PatternIDOverflow {
/// The maximum possible id.
max: u64,
/// The maximum ID requested.
requested_max: u64,
},
/// Occurs when a pattern string is given to the Aho-Corasick constructor
/// that is too long.
PatternTooLong {
/// The ID of the pattern that was too long.
pattern: PatternID,
/// The length that was too long.
len: usize,
},
}
impl BuildError {
pub(crate) fn state_id_overflow(
max: u64,
requested_max: u64,
) -> BuildError {
BuildError { kind: ErrorKind::StateIDOverflow { max, requested_max } }
}
pub(crate) fn pattern_id_overflow(
max: u64,
requested_max: u64,
) -> BuildError {
BuildError {
kind: ErrorKind::PatternIDOverflow { max, requested_max },
}
}
pub(crate) fn pattern_too_long(
pattern: PatternID,
len: usize,
) -> BuildError {
BuildError { kind: ErrorKind::PatternTooLong { pattern, len } }
}
}
#[cfg(feature = "std")]
impl std::error::Error for BuildError {}
impl core::fmt::Display for BuildError {
fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
match self.kind {
ErrorKind::StateIDOverflow { max, requested_max } => {
write!(
f,
"state identifier overflow: failed to create state ID \
from {}, which exceeds the max of {}",
requested_max, max,
)
}
ErrorKind::PatternIDOverflow { max, requested_max } => {
write!(
f,
"pattern identifier overflow: failed to create pattern ID \
from {}, which exceeds the max of {}",
requested_max, max,
)
}
ErrorKind::PatternTooLong { pattern, len } => {
write!(
f,
"pattern {} with length {} exceeds \
the maximum pattern length of {}",
pattern.as_usize(),
len,
SmallIndex::MAX.as_usize(),
)
}
}
}
}
/// An error that occurred during an Aho-Corasick search.
///
/// An error that occurs during a search is limited to some kind of
/// misconfiguration that resulted in an illegal call. Stated differently,
/// whether an error occurs is not dependent on the specific bytes in the
/// haystack.
///
/// Examples of misconfiguration:
///
/// * Executing a stream or overlapping search on a searcher that was built was
/// something other than [`MatchKind::Standard`](crate::MatchKind::Standard)
/// semantics.
/// * Requested an anchored or an unanchored search on a searcher that doesn't
/// support unanchored or anchored searches, respectively.
///
/// When the `std` feature is enabled, this implements the `std::error::Error`
/// trait.
#[derive(Clone, Debug, Eq, PartialEq)]
pub struct MatchError(alloc::boxed::Box<MatchErrorKind>);
impl MatchError {
/// Create a new error value with the given kind.
///
/// This is a more verbose version of the kind-specific constructors, e.g.,
/// `MatchError::unsupported_stream`.
pub fn new(kind: MatchErrorKind) -> MatchError {
MatchError(alloc::boxed::Box::new(kind))
}
/// Returns a reference to the underlying error kind.
pub fn kind(&self) -> &MatchErrorKind {
&self.0
}
/// Create a new "invalid anchored search" error. This occurs when the
/// caller requests an anchored search but where anchored searches aren't
/// supported.
///
/// This is the same as calling `MatchError::new` with a
/// [`MatchErrorKind::InvalidInputAnchored`] kind.
pub fn invalid_input_anchored() -> MatchError {
MatchError::new(MatchErrorKind::InvalidInputAnchored)
}
/// Create a new "invalid unanchored search" error. This occurs when the
/// caller requests an unanchored search but where unanchored searches
/// aren't supported.
///
/// This is the same as calling `MatchError::new` with a
/// [`MatchErrorKind::InvalidInputUnanchored`] kind.
pub fn invalid_input_unanchored() -> MatchError {
MatchError::new(MatchErrorKind::InvalidInputUnanchored)
}
/// Create a new "unsupported stream search" error. This occurs when the
/// caller requests a stream search while using an Aho-Corasick automaton
/// with a match kind other than [`MatchKind::Standard`].
///
/// The match kind given should be the match kind of the automaton. It
/// should never be `MatchKind::Standard`.
pub fn unsupported_stream(got: MatchKind) -> MatchError {
MatchError::new(MatchErrorKind::UnsupportedStream { got })
}
/// Create a new "unsupported overlapping search" error. This occurs when
/// the caller requests an overlapping search while using an Aho-Corasick
/// automaton with a match kind other than [`MatchKind::Standard`].
///
/// The match kind given should be the match kind of the automaton. It
/// should never be `MatchKind::Standard`.
pub fn unsupported_overlapping(got: MatchKind) -> MatchError {
MatchError::new(MatchErrorKind::UnsupportedOverlapping { got })
}
/// Create a new "unsupported empty pattern" error. This occurs when the
/// caller requests a search for which matching an automaton that contains
/// an empty pattern string is not supported.
pub fn unsupported_empty() -> MatchError {
MatchError::new(MatchErrorKind::UnsupportedEmpty)
}
}
/// The underlying kind of a [`MatchError`].
///
/// This is a **non-exhaustive** enum. That means new variants may be added in
/// a semver-compatible release.
#[non_exhaustive]
#[derive(Clone, Debug, Eq, PartialEq)]
pub enum MatchErrorKind {
/// An error indicating that an anchored search was requested, but from a
/// searcher that was built without anchored support.
InvalidInputAnchored,
/// An error indicating that an unanchored search was requested, but from a
/// searcher that was built without unanchored support.
InvalidInputUnanchored,
/// An error indicating that a stream search was attempted on an
/// Aho-Corasick automaton with an unsupported `MatchKind`.
UnsupportedStream {
/// The match semantics for the automaton that was used.
got: MatchKind,
},
/// An error indicating that an overlapping search was attempted on an
/// Aho-Corasick automaton with an unsupported `MatchKind`.
UnsupportedOverlapping {
/// The match semantics for the automaton that was used.
got: MatchKind,
},
/// An error indicating that the operation requested doesn't support
/// automatons that contain an empty pattern string.
UnsupportedEmpty,
}
#[cfg(feature = "std")]
impl std::error::Error for MatchError {}
impl core::fmt::Display for MatchError {
fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
match *self.kind() {
MatchErrorKind::InvalidInputAnchored => {
write!(f, "anchored searches are not supported or enabled")
}
MatchErrorKind::InvalidInputUnanchored => {
write!(f, "unanchored searches are not supported or enabled")
}
MatchErrorKind::UnsupportedStream { got } => {
write!(
f,
"match kind {:?} does not support stream searching",
got,
)
}
MatchErrorKind::UnsupportedOverlapping { got } => {
write!(
f,
"match kind {:?} does not support overlapping searches",
got,
)
}
MatchErrorKind::UnsupportedEmpty => {
write!(
f,
"matching with an empty pattern string is not \
supported for this operation",
)
}
}
}
}