css-inline 0.22.0

//! Errors that may happen during inlining.
use cssparser::{BasicParseErrorKind, ParseError, ParseErrorKind, SourceLocation};
use std::{
    borrow::Cow,
    error::Error,
    fmt,
    fmt::{Display, Formatter},
    io,
};

/// Inlining error
#[derive(Debug)]
pub enum InlineError {
    /// Missing stylesheet file.
    MissingStyleSheet {
        /// Path to the missing file.
        path: String,
    },
    /// Input-output error. May happen during writing the resulting HTML or retrieving a stylesheet
    /// from the filesystem.
    IO(io::Error),
    /// Network-related problem. E.g. resource is not available.
    #[cfg(feature = "http")]
    Network {
        /// Original network error.
        error: reqwest::Error,
        /// The stylesheet location caused the error.
        location: String,
    },
    /// Syntax errors or unsupported selectors.
    ParseError(Cow<'static, str>),
}

impl From<io::Error> for InlineError {
    fn from(error: io::Error) -> Self {
        Self::IO(error)
    }
}

impl Error for InlineError {
    fn source(&self) -> Option<&(dyn Error + 'static)> {
        match self {
            InlineError::IO(error) => Some(error),
            #[cfg(feature = "http")]
            InlineError::Network { error, .. } => Some(error),
            InlineError::MissingStyleSheet { .. } | InlineError::ParseError(_) => None,
        }
    }
}

impl Display for InlineError {
    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
        match self {
            Self::IO(error) => error.fmt(f),
            #[cfg(feature = "http")]
            Self::Network { error, location } => f.write_fmt(format_args!("{error}: {location}")),
            Self::ParseError(error) => f.write_str(error),
            Self::MissingStyleSheet { path } => {
                f.write_fmt(format_args!("Missing stylesheet file: {path}"))
            }
        }
    }
}

impl From<(ParseError<()>, &str, SourceLocation)> for InlineError {
    fn from(error: (ParseError<()>, &str, SourceLocation)) -> Self {
        // `cssparser` does not store the offending token or rule name; the source slice ends with it
        let source = error.1;
        match error.0.kind {
            ParseErrorKind::Basic(kind) => match kind {
                BasicParseErrorKind::UnexpectedToken => {
                    let mut parser = cssparser::Parser::new(source);
                    let mut last = None;
                    while let Ok(token) = parser.next() {
                        last = Some(format!("{token:?}"));
                    }
                    match last {
                        Some(token) => {
                            Self::ParseError(Cow::Owned(format!("Unexpected token: {token}")))
                        }
                        None => Self::ParseError(Cow::Borrowed("Unexpected token")),
                    }
                }
                BasicParseErrorKind::EndOfInput => Self::ParseError(Cow::Borrowed("End of input")),
                BasicParseErrorKind::AtRuleInvalid => {
                    let name = source
                        .trim_start()
                        .trim_start_matches('@')
                        .split(|c: char| c.is_whitespace() || matches!(c, '{' | ';'))
                        .next()
                        .unwrap_or_default();
                    Self::ParseError(Cow::Owned(format!("Invalid @ rule: {name}")))
                }
                BasicParseErrorKind::TooManyNestedBlocks => {
                    Self::ParseError(Cow::Borrowed("Too many nested blocks"))
                }
                BasicParseErrorKind::AtRuleBodyInvalid => {
                    Self::ParseError(Cow::Borrowed("Invalid @ rule body"))
                }
                BasicParseErrorKind::QualifiedRuleInvalid => {
                    Self::ParseError(Cow::Borrowed("Invalid qualified rule"))
                }
            },
            ParseErrorKind::Custom(()) => Self::ParseError(Cow::Borrowed("Unknown error")),
        }
    }
}