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use crate::tag::Tag;
use std::error;
use std::fmt;
use std::io;
use std::string;
/// Type alias for the result of tag operations.
pub type Result<T> = std::result::Result<T, Error>;
/// Takes a tag result and maps any partial tag to Ok. An Ok result is left untouched. An Err
/// without partial tag is returned as the initial error.
///
/// # Example
/// ```
/// use id3::{Tag, Error, ErrorKind, partial_tag_ok};
///
/// let rs = Err(Error{
/// kind: ErrorKind::Parsing,
/// description: "frame 12 could not be decoded".to_string(),
/// partial_tag: Some(Tag::new()),
/// });
/// assert!(partial_tag_ok(rs).is_ok());
/// ```
pub fn partial_tag_ok(rs: Result<Tag>) -> Result<Tag> {
match rs {
Ok(tag) => Ok(tag),
Err(Error {
partial_tag: Some(tag),
..
}) => Ok(tag),
Err(err) => Err(err),
}
}
/// Takes a tag result and maps the NoTag kind to None. Any other error is returned as Err.
///
/// # Example
/// ```
/// use id3::{Tag, Error, ErrorKind, no_tag_ok};
///
/// let rs = Err(Error{
/// kind: ErrorKind::NoTag,
/// description: "the file contains no ID3 tag".to_string(),
/// partial_tag: None,
/// });
/// assert!(matches!(no_tag_ok(rs), Ok(None)));
///
/// let rs = Err(Error{
/// kind: ErrorKind::Parsing,
/// description: "frame 12 could not be decoded".to_string(),
/// partial_tag: Some(Tag::new()),
/// });
/// assert!(no_tag_ok(rs).is_err());
/// ```
pub fn no_tag_ok(rs: Result<Tag>) -> Result<Option<Tag>> {
match rs {
Ok(tag) => Ok(Some(tag)),
Err(Error {
kind: ErrorKind::NoTag,
..
}) => Ok(None),
Err(err) => Err(err),
}
}
/// Kinds of errors that may occur while performing metadata operations.
#[derive(Debug)]
pub enum ErrorKind {
/// An error kind indicating that an IO error has occurred. Contains the original io::Error.
Io(io::Error),
/// An error kind indicating that a string decoding error has occurred. Contains the invalid
/// bytes.
StringDecoding(Vec<u8>),
/// An error kind indicating that the reader does not contain an ID3 tag.
NoTag,
/// An error kind indicating that parsing of some binary data has failed.
Parsing,
/// An error kind indicating that some input to a function was invalid.
InvalidInput,
/// An error kind indicating that a feature is not supported.
UnsupportedFeature,
}
/// A structure able to represent any error that may occur while performing metadata operations.
pub struct Error {
/// The kind of error.
pub kind: ErrorKind,
/// A human readable string describing the error.
pub description: String,
/// If any, the part of the tag that was able to be decoded before the error occurred.
pub partial_tag: Option<Tag>,
}
impl Error {
/// Creates a new `Error` using the error kind and description.
pub fn new(kind: ErrorKind, description: impl Into<String>) -> Error {
Error {
kind,
description: description.into(),
partial_tag: None,
}
}
/// Creates a new `Error` using the error kind and description.
pub(crate) fn with_tag(self, tag: Tag) -> Error {
Error {
partial_tag: Some(tag),
..self
}
}
}
impl error::Error for Error {
fn source(&self) -> Option<&(dyn error::Error + 'static)> {
match self.kind {
ErrorKind::Io(ref err) => Some(err),
_ => None,
}
}
}
impl From<io::Error> for Error {
fn from(err: io::Error) -> Error {
Error {
kind: ErrorKind::Io(err),
description: "".to_string(),
partial_tag: None,
}
}
}
impl From<string::FromUtf8Error> for Error {
fn from(err: string::FromUtf8Error) -> Error {
Error {
kind: ErrorKind::StringDecoding(err.into_bytes()),
description: "data is not valid utf-8".to_string(),
partial_tag: None,
}
}
}
impl fmt::Debug for Error {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match self.description.is_empty() {
true => write!(f, "{:?}", self.kind),
false => write!(f, "{:?}: {}", self.kind, self.description),
}
}
}
impl fmt::Display for Error {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match self.description.is_empty() {
true => write!(f, "{}", self.kind),
false => write!(f, "{}: {}", self.kind, self.description),
}
}
}
impl fmt::Display for ErrorKind {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match self {
ErrorKind::Io(io_error) => write!(f, "IO: {}", io_error),
ErrorKind::StringDecoding(_) => write!(f, "StringDecoding"),
ErrorKind::NoTag => write!(f, "NoTag"),
ErrorKind::Parsing => write!(f, "Parsing"),
ErrorKind::InvalidInput => write!(f, "InvalidInput"),
ErrorKind::UnsupportedFeature => write!(f, "UnsupportedFeature"),
}
}
}