exif/
error.rs

1//
2// Copyright (c) 2016 KAMADA Ken'ichi.
3// All rights reserved.
4//
5// Redistribution and use in source and binary forms, with or without
6// modification, are permitted provided that the following conditions
7// are met:
8// 1. Redistributions of source code must retain the above copyright
9//    notice, this list of conditions and the following disclaimer.
10// 2. Redistributions in binary form must reproduce the above copyright
11//    notice, this list of conditions and the following disclaimer in the
12//    documentation and/or other materials provided with the distribution.
13//
14// THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17// ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20// OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22// LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23// OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24// SUCH DAMAGE.
25//
26
27use std::error;
28use std::fmt;
29use std::io;
30use std::sync::Mutex;
31
32/// An error returned when parsing of Exif data fails.
33#[derive(Debug)]
34#[non_exhaustive]
35pub enum Error {
36    /// Input data was malformed or truncated.
37    InvalidFormat(&'static str),
38    /// Input data could not be read due to an I/O error and
39    /// a `std::io::Error` value is associated with this variant.
40    Io(io::Error),
41    /// Exif attribute information was not found in an image file
42    /// such as JPEG.
43    NotFound(&'static str),
44    /// The value of the field is blank.  Some fields have blank values
45    /// whose meanings are defined as "unknown".  Such a blank value
46    /// should be treated the same as the absence of the field.
47    BlankValue(&'static str),
48    /// Field values or image data are too big to encode.
49    TooBig(&'static str),
50    /// The field type is not supported and cannnot be encoded.
51    NotSupported(&'static str),
52    /// The field has an unexpected value.
53    UnexpectedValue(&'static str),
54    /// Partially-parsed result and errors.  This can be returned only when
55    /// `Reader::continue_on_error` is enabled.
56    PartialResult(PartialResult),
57}
58
59impl Error {
60    /// Extracts `Exif` and `Vec<Error>` from `Error::PartialResult`.
61    ///
62    /// If `self` is `Error::PartialResult`,
63    /// ignored errors are passed to `f` as `Vec<Error>` and
64    /// partially-parsed result is retuend in `Ok`.
65    /// Otherwise, `Err(self)` is returned.
66    pub fn distill_partial_result<F>(self, f: F) -> Result<crate::Exif, Self>
67    where F: FnOnce(Vec<Error>) {
68        if let Error::PartialResult(partial) = self {
69            let (exif, errors) = partial.into_inner();
70            f(errors);
71            Ok(exif)
72        } else {
73            Err(self)
74        }
75    }
76}
77
78impl From<io::Error> for Error {
79    fn from(err: io::Error) -> Error {
80        Error::Io(err)
81    }
82}
83
84impl fmt::Display for Error {
85    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
86        match *self {
87            Error::InvalidFormat(msg) => f.write_str(msg),
88            Error::Io(ref err) => err.fmt(f),
89            Error::NotFound(ctn) => write!(f, "No Exif data found in {}", ctn),
90            Error::BlankValue(msg) => f.write_str(msg),
91            Error::TooBig(msg) => f.write_str(msg),
92            Error::NotSupported(msg) => f.write_str(msg),
93            Error::UnexpectedValue(msg) => f.write_str(msg),
94            Error::PartialResult(ref pr) =>
95                write!(f, "Partial result with {} fields and {} errors",
96                       pr.0.0.lock().expect("should not panic").fields().len(),
97                       pr.0.1.len()),
98        }
99    }
100}
101
102impl error::Error for Error {
103    fn source(&self) -> Option<&(dyn error::Error + 'static)> {
104        match *self {
105            Error::InvalidFormat(_) => None,
106            Error::Io(ref err) => Some(err),
107            Error::NotFound(_) => None,
108            Error::BlankValue(_) => None,
109            Error::TooBig(_) => None,
110            Error::NotSupported(_) => None,
111            Error::UnexpectedValue(_) => None,
112            Error::PartialResult(_) => None,
113        }
114    }
115}
116
117/// Partially-parsed result and errors.
118pub struct PartialResult(Box<(Mutex<crate::Exif>, Vec<Error>)>);
119
120impl PartialResult {
121    pub(crate) fn new(exif: crate::Exif, errors: Vec<Error>) -> Self {
122        Self(Box::new((Mutex::new(exif), errors)))
123    }
124
125    /// Returns partially-parsed `Exif` and ignored `Error`s.
126    pub fn into_inner(self) -> (crate::Exif, Vec<Error>) {
127        let (exif, errors) = *self.0;
128        (exif.into_inner().expect("should not panic"), errors)
129    }
130}
131
132impl fmt::Debug for PartialResult {
133    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
134        write!(f, "PartialResult(Exif({} fields), {:?})",
135               self.0.0.lock().expect("should not panic").fields().len(),
136               self.0.1)
137    }
138}
139
140#[cfg(test)]
141mod tests {
142    use super::*;
143
144    // Check compatibility with anyhow::Error, which requires Send, Sync,
145    // and 'static on error types.
146    #[test]
147    fn is_send_sync_static() {
148        let _: Box<dyn Send + Sync + 'static> =
149            Box::new(Error::InvalidFormat("test"));
150    }
151}
exif/error.rs

exif/
error.rs
