tantivy_fst/raw/
error.rs

1use std::error;
2use std::fmt;
3use std::str;
4use std::string::FromUtf8Error;
5
6use crate::raw::FstType;
7
8/// An error that occurred while using a finite state transducer.
9pub enum Error {
10    /// A version mismatch occurred while reading a finite state transducer.
11    ///
12    /// This occurs when the API version (of the crate) does not match the
13    /// version encoded in the finite state transducer.
14    ///
15    /// When this error is encountered, there are only two ways to fix it:
16    ///
17    /// 1. Change the version of the library to one that is compatible with
18    ///    the given finite state transducer.
19    /// 2. Rebuild the finite state transducer.
20    Version {
21        /// The expected version, which is hard-coded into the current version
22        /// of this crate.
23        expected: u64,
24        /// The version read from the finite state transducer.
25        got: u64,
26    },
27    /// An unexpected error occurred while reading a finite state transducer.
28    /// Usually this occurs because the data is corrupted or is not actually
29    /// a finite state transducer serialized by this library.
30    Format,
31    /// A duplicate key was inserted into a finite state transducer, which is
32    /// not allowed.
33    DuplicateKey {
34        /// The duplicate key.
35        got: Vec<u8>,
36    },
37    /// A key was inserted out of order into a finite state transducer.
38    ///
39    /// Keys must always be inserted in lexicographic order.
40    OutOfOrder {
41        /// The last key successfully inserted.
42        previous: Vec<u8>,
43        /// The key that caused this error to occur.
44        got: Vec<u8>,
45    },
46    /// A finite state transducer with an unexpected type was found.
47    ///
48    /// This is not currently used in this crate, but callers may wish to
49    /// employ its use for alternative data structures implemented on top of
50    /// finite state transducers.
51    WrongType {
52        /// The expected finite state transducer type.
53        expected: FstType,
54        /// The type read from a finite state transducer.
55        got: FstType,
56    },
57    /// An error that occurred when trying to decode a UTF-8 byte key.
58    FromUtf8(FromUtf8Error),
59}
60
61impl fmt::Display for Error {
62    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
63        use self::Error::*;
64        match *self {
65            FromUtf8(ref err) => err.fmt(f),
66            Version { expected, got } => write!(
67                f,
68                "\
69Error opening FST: expected API version {}, got API version {}.
70It looks like the FST you're trying to open is either not an FST file or it
71was generated with a different version of the 'fst' crate. You'll either need
72to change the version of the 'fst' crate you're using, or re-generate the
73FST.",
74                expected, got
75            ),
76            Format => write!(
77                f,
78                "\
79Error opening FST: An unknown error occurred. This usually means you're trying
80to read data that isn't actually an encoded FST."
81            ),
82            DuplicateKey { ref got } => write!(
83                f,
84                "\
85                 Error inserting duplicate key: {}.",
86                format_bytes(&*got)
87            ),
88            OutOfOrder {
89                ref previous,
90                ref got,
91            } => write!(
92                f,
93                "\
94Error inserting out-of-order key: {}. (Previous key was {}.) Keys must be
95inserted in lexicographic order.",
96                format_bytes(&*got),
97                format_bytes(&*previous)
98            ),
99            WrongType { expected, got } => write!(
100                f,
101                "\
102                 Error opening FST: expected type {}, got type {}.",
103                expected, got
104            ),
105        }
106    }
107}
108
109impl fmt::Debug for Error {
110    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
111        fmt::Display::fmt(self, f)
112    }
113}
114
115impl error::Error for Error {
116    fn cause(&self) -> Option<&dyn error::Error> {
117        match *self {
118            Error::FromUtf8(ref err) => Some(err),
119            _ => None,
120        }
121    }
122}
123
124impl From<FromUtf8Error> for Error {
125    #[inline]
126    fn from(err: FromUtf8Error) -> Self {
127        Error::FromUtf8(err)
128    }
129}
130
131/// Attempt to convert an arbitrary byte string to a more convenient display
132/// form.
133///
134/// Essentially, try to decode the bytes as UTF-8 and show that. Failing that,
135/// just show the sequence of bytes.
136fn format_bytes(bytes: &[u8]) -> String {
137    match str::from_utf8(bytes) {
138        Ok(s) => s.to_owned(),
139        Err(_) => format!("{:?}", bytes),
140    }
141}
tantivy_fst/raw/error.rs

tantivy_fst/raw/
error.rs
