1use crate::util::{
2 primitives::{PatternID, SmallIndex},
3 search::MatchKind,
4};
5
6/// An error that occurred during the construction of an Aho-Corasick
7/// automaton.
8///
9/// Build errors occur when some kind of limit has been exceeded, either in the
10/// number of states, the number of patterns of the length of a pattern. These
11/// limits aren't part of the public API, but they should generally be large
12/// enough to handle most use cases.
13///
14/// When the `std` feature is enabled, this implements the `std::error::Error`
15/// trait.
16#[derive(Clone, Debug)]
17pub struct BuildError {
18 kind: ErrorKind,
19}
20
21/// The kind of error that occurred.
22#[derive(Clone, Debug)]
23enum ErrorKind {
24 /// An error that occurs when allocating a new state would result in an
25 /// identifier that exceeds the capacity of a `StateID`.
26 StateIDOverflow {
27 /// The maximum possible id.
28 max: u64,
29 /// The maximum ID requested.
30 requested_max: u64,
31 },
32 /// An error that occurs when adding a pattern to an Aho-Corasick
33 /// automaton would result in an identifier that exceeds the capacity of a
34 /// `PatternID`.
35 PatternIDOverflow {
36 /// The maximum possible id.
37 max: u64,
38 /// The maximum ID requested.
39 requested_max: u64,
40 },
41 /// Occurs when a pattern string is given to the Aho-Corasick constructor
42 /// that is too long.
43 PatternTooLong {
44 /// The ID of the pattern that was too long.
45 pattern: PatternID,
46 /// The length that was too long.
47 len: usize,
48 },
49}
50
51impl BuildError {
52 pub(crate) fn state_id_overflow(
53 max: u64,
54 requested_max: u64,
55 ) -> BuildError {
56 BuildError { kind: ErrorKind::StateIDOverflow { max, requested_max } }
57 }
58
59 pub(crate) fn pattern_id_overflow(
60 max: u64,
61 requested_max: u64,
62 ) -> BuildError {
63 BuildError {
64 kind: ErrorKind::PatternIDOverflow { max, requested_max },
65 }
66 }
67
68 pub(crate) fn pattern_too_long(
69 pattern: PatternID,
70 len: usize,
71 ) -> BuildError {
72 BuildError { kind: ErrorKind::PatternTooLong { pattern, len } }
73 }
74}
75
76#[cfg(feature = "std")]
77impl std::error::Error for BuildError {}
78
79impl core::fmt::Display for BuildError {
80 fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
81 match self.kind {
82 ErrorKind::StateIDOverflow { max, requested_max } => {
83 write!(
84 f,
85 "state identifier overflow: failed to create state ID \
86 from {}, which exceeds the max of {}",
87 requested_max, max,
88 )
89 }
90 ErrorKind::PatternIDOverflow { max, requested_max } => {
91 write!(
92 f,
93 "pattern identifier overflow: failed to create pattern ID \
94 from {}, which exceeds the max of {}",
95 requested_max, max,
96 )
97 }
98 ErrorKind::PatternTooLong { pattern, len } => {
99 write!(
100 f,
101 "pattern {} with length {} exceeds \
102 the maximum pattern length of {}",
103 pattern.as_usize(),
104 len,
105 SmallIndex::MAX.as_usize(),
106 )
107 }
108 }
109 }
110}
111
112/// An error that occurred during an Aho-Corasick search.
113///
114/// An error that occurs during a search is limited to some kind of
115/// misconfiguration that resulted in an illegal call. Stated differently,
116/// whether an error occurs is not dependent on the specific bytes in the
117/// haystack.
118///
119/// Examples of misconfiguration:
120///
121/// * Executing a stream or overlapping search on a searcher that was built was
122/// something other than [`MatchKind::Standard`](crate::MatchKind::Standard)
123/// semantics.
124/// * Requested an anchored or an unanchored search on a searcher that doesn't
125/// support unanchored or anchored searches, respectively.
126///
127/// When the `std` feature is enabled, this implements the `std::error::Error`
128/// trait.
129#[derive(Clone, Debug, Eq, PartialEq)]
130pub struct MatchError(alloc::boxed::Box<MatchErrorKind>);
131
132impl MatchError {
133 /// Create a new error value with the given kind.
134 ///
135 /// This is a more verbose version of the kind-specific constructors, e.g.,
136 /// `MatchError::unsupported_stream`.
137 pub fn new(kind: MatchErrorKind) -> MatchError {
138 MatchError(alloc::boxed::Box::new(kind))
139 }
140
141 /// Returns a reference to the underlying error kind.
142 pub fn kind(&self) -> &MatchErrorKind {
143 &self.0
144 }
145
146 /// Create a new "invalid anchored search" error. This occurs when the
147 /// caller requests an anchored search but where anchored searches aren't
148 /// supported.
149 ///
150 /// This is the same as calling `MatchError::new` with a
151 /// [`MatchErrorKind::InvalidInputAnchored`] kind.
152 pub fn invalid_input_anchored() -> MatchError {
153 MatchError::new(MatchErrorKind::InvalidInputAnchored)
154 }
155
156 /// Create a new "invalid unanchored search" error. This occurs when the
157 /// caller requests an unanchored search but where unanchored searches
158 /// aren't supported.
159 ///
160 /// This is the same as calling `MatchError::new` with a
161 /// [`MatchErrorKind::InvalidInputUnanchored`] kind.
162 pub fn invalid_input_unanchored() -> MatchError {
163 MatchError::new(MatchErrorKind::InvalidInputUnanchored)
164 }
165
166 /// Create a new "unsupported stream search" error. This occurs when the
167 /// caller requests a stream search while using an Aho-Corasick automaton
168 /// with a match kind other than [`MatchKind::Standard`].
169 ///
170 /// The match kind given should be the match kind of the automaton. It
171 /// should never be `MatchKind::Standard`.
172 pub fn unsupported_stream(got: MatchKind) -> MatchError {
173 MatchError::new(MatchErrorKind::UnsupportedStream { got })
174 }
175
176 /// Create a new "unsupported overlapping search" error. This occurs when
177 /// the caller requests an overlapping search while using an Aho-Corasick
178 /// automaton with a match kind other than [`MatchKind::Standard`].
179 ///
180 /// The match kind given should be the match kind of the automaton. It
181 /// should never be `MatchKind::Standard`.
182 pub fn unsupported_overlapping(got: MatchKind) -> MatchError {
183 MatchError::new(MatchErrorKind::UnsupportedOverlapping { got })
184 }
185
186 /// Create a new "unsupported empty pattern" error. This occurs when the
187 /// caller requests a search for which matching an automaton that contains
188 /// an empty pattern string is not supported.
189 pub fn unsupported_empty() -> MatchError {
190 MatchError::new(MatchErrorKind::UnsupportedEmpty)
191 }
192}
193
194/// The underlying kind of a [`MatchError`].
195///
196/// This is a **non-exhaustive** enum. That means new variants may be added in
197/// a semver-compatible release.
198#[non_exhaustive]
199#[derive(Clone, Debug, Eq, PartialEq)]
200pub enum MatchErrorKind {
201 /// An error indicating that an anchored search was requested, but from a
202 /// searcher that was built without anchored support.
203 InvalidInputAnchored,
204 /// An error indicating that an unanchored search was requested, but from a
205 /// searcher that was built without unanchored support.
206 InvalidInputUnanchored,
207 /// An error indicating that a stream search was attempted on an
208 /// Aho-Corasick automaton with an unsupported `MatchKind`.
209 UnsupportedStream {
210 /// The match semantics for the automaton that was used.
211 got: MatchKind,
212 },
213 /// An error indicating that an overlapping search was attempted on an
214 /// Aho-Corasick automaton with an unsupported `MatchKind`.
215 UnsupportedOverlapping {
216 /// The match semantics for the automaton that was used.
217 got: MatchKind,
218 },
219 /// An error indicating that the operation requested doesn't support
220 /// automatons that contain an empty pattern string.
221 UnsupportedEmpty,
222}
223
224#[cfg(feature = "std")]
225impl std::error::Error for MatchError {}
226
227impl core::fmt::Display for MatchError {
228 fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
229 match *self.kind() {
230 MatchErrorKind::InvalidInputAnchored => {
231 write!(f, "anchored searches are not supported or enabled")
232 }
233 MatchErrorKind::InvalidInputUnanchored => {
234 write!(f, "unanchored searches are not supported or enabled")
235 }
236 MatchErrorKind::UnsupportedStream { got } => {
237 write!(
238 f,
239 "match kind {:?} does not support stream searching",
240 got,
241 )
242 }
243 MatchErrorKind::UnsupportedOverlapping { got } => {
244 write!(
245 f,
246 "match kind {:?} does not support overlapping searches",
247 got,
248 )
249 }
250 MatchErrorKind::UnsupportedEmpty => {
251 write!(
252 f,
253 "matching with an empty pattern string is not \
254 supported for this operation",
255 )
256 }
257 }
258 }
259}
260