exr/
error.rs

1
2//! Error type definitions.
3
4use std::borrow::Cow;
5use std::io::ErrorKind;
6pub use std::io::Error as IoError;
7pub use std::io::Result as IoResult;
8use std::convert::TryFrom;
9use std::error;
10use std::fmt;
11use std::num::TryFromIntError;
12
13
14// Export types
15
16/// A result that may contain an exr error.
17pub type Result<T> = std::result::Result<T, Error>;
18
19/// A result that, if ok, contains nothing, and otherwise contains an exr error.
20pub type UnitResult = Result<()>;
21
22
23/// An error that may happen while reading or writing an exr file.
24/// Distinguishes between three types of errors:
25/// unsupported features, invalid data, and file system errors.
26#[derive(Debug)]
27pub enum Error {
28
29    /// Reading or Writing the file has been aborted by the caller.
30    /// This error will never be triggered by this crate itself,
31    /// only by users of this library.
32    /// It exists to be returned from a progress callback.
33    Aborted, // FIXME remove?? is not used really?
34
35    /// The contents of the file are not supported by
36    /// this specific implementation of open exr,
37    /// even though the data may be valid.
38    NotSupported(Cow<'static, str>),
39
40    /// The contents of the image are contradicting or insufficient.
41    /// Also returned for `ErrorKind::UnexpectedEof` errors.
42    Invalid(Cow<'static, str>),
43
44    /// The underlying byte stream could not be read successfully,
45    /// probably due to file system related errors.
46    Io(IoError),
47}
48
49
50impl Error {
51
52    /// Create an error of the variant `Invalid`.
53    pub(crate) fn invalid(message: impl Into<Cow<'static, str>>) -> Self {
54        Error::Invalid(message.into())
55    }
56
57    /// Create an error of the variant `NotSupported`.
58    pub(crate) fn unsupported(message: impl Into<Cow<'static, str>>) -> Self {
59        Error::NotSupported(message.into())
60    }
61}
62
63/// Enable using the `?` operator on `std::io::Result`.
64impl From<IoError> for Error {
65    fn from(error: IoError) -> Self {
66        if error.kind() == ErrorKind::UnexpectedEof {
67            Error::invalid("reference to missing bytes")
68        }
69        else {
70            Error::Io(error)
71        }
72    }
73}
74
75// TODO use `usize::try_from(x)?` everywhere
76impl From<TryFromIntError> for Error {
77    fn from(_: TryFromIntError) -> Self {
78        Error::invalid("invalid size")
79    }
80}
81
82impl error::Error for Error {
83    fn source(&self) -> Option<&(dyn error::Error + 'static)> {
84        match *self {
85            Error::Io(ref err) => Some(err),
86            _ => None,
87        }
88    }
89}
90
91impl fmt::Display for Error {
92    fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
93        match self {
94            Error::Io(err) => err.fmt(formatter),
95            Error::NotSupported(message) => write!(formatter, "not supported: {}", message),
96            Error::Invalid(message) => write!(formatter, "invalid: {}", message),
97            Error::Aborted => write!(formatter, "cancelled"),
98        }
99    }
100}
101
102/// Typically used during decoding. Return error on invalid range.
103#[inline]
104pub(crate) fn i32_to_usize(value: i32, error_message: &'static str) -> Result<usize> {
105    usize::try_from(value).map_err(|_| {
106        if value < 0 { Error::invalid(error_message) }
107        else { Error::unsupported(error_message) }
108    })
109}
110
111/// Typically used during encoding. Return error on overflow.
112#[inline]
113pub(crate) fn usize_to_u32(value: usize, error_message: &'static str) -> Result<u32> {
114    u32::try_from(value).map_err(|_| Error::invalid(error_message))
115}
116
117/// Typically used during encoding. Return error on invalid range.
118#[inline]
119pub(crate) fn usize_to_u16(value: usize, error_message: &'static str) -> Result<u16> {
120    u16::try_from(value).map_err(|_| Error::invalid(error_message))
121}
122
123/// Typically used during decoding. Return error on invalid range.
124#[inline]
125pub(crate) fn u64_to_usize(value: u64, error_message: &'static str) -> Result<usize> {
126    usize::try_from(value).map_err(|_| Error::unsupported(error_message))
127}
128
129/// Typically used during decoding. Return error on invalid range.
130#[inline]
131pub(crate) fn u32_to_usize(value: u32, error_message: &'static str) -> Result<usize> {
132    usize::try_from(value).map_err(|_| Error::unsupported(error_message))
133}
134
135/// Typically used during encoding. Return error on invalid range.
136#[inline]
137pub(crate) fn usize_to_i32(value: usize, error_message: &'static str) -> Result<i32> {
138    i32::try_from(value).map_err(|_| Error::invalid(error_message))
139}
140
141/// Typically used during encoding. Return error on invalid range.
142#[inline]
143pub(crate) fn usize_to_u64(value: usize, error_message: &'static str) -> Result<u64> {
144    u64::try_from(value).map_err(|_| Error::invalid(error_message))
145}
exr/error.rs

exr/
error.rs
