1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148

use crate::css::Value;
#[cfg(feature = "clap")]
use clap;
use nom;
use std::convert::From;
use std::path::PathBuf;
use std::string::FromUtf8Error;
use std::{fmt, io};

/// Most functions in rsass that returns a Result uses this Error type.
#[derive(Debug)]
pub enum Error {
    Input(PathBuf, io::Error),
    IoError(io::Error),
    Encoding(FromUtf8Error),
    BadValue(String),
    BadArguments(String),
    ParseError {
        file: String,
        pos: ErrPos,
        kind: Option<nom::error::ErrorKind>,
    },
    S(String),
    UndefinedVariable(String),
}

impl Error {
    pub fn bad_value(expected: &str, actual: &Value) -> Self {
        Error::BadValue(format!(
            "expected {}, got {} = {}",
            expected,
            actual.type_name(),
            actual
        ))
    }

    /// Wrong kind of argument to a sass function.
    /// `expected` is a string describing what the parameter should
    /// have been, `actual` is the argument.
    pub fn badarg(expected: &str, actual: &Value) -> Error {
        Error::BadArguments(format!(
            "expected {}, got {} = {}",
            expected,
            actual.type_name(),
            actual
        ))
    }

    /// Multiple-argument variant of `badarg`.
    pub fn badargs(expected: &[&str], actual: &[&Value]) -> Error {
        // TODO Better message!
        Error::BadArguments(format!(
            "expected {:?}, got {:?}",
            expected, actual
        ))
    }

    pub fn undefined_variable(name: &str) -> Self {
        Error::UndefinedVariable(name.to_string())
    }
}

impl fmt::Display for Error {
    fn fmt(&self, out: &mut fmt::Formatter) -> fmt::Result {
        match *self {
            Error::S(ref s) => write!(out, "{}", s),
            Error::Input(ref p, ref e) => {
                write!(out, "Failed to read {:?}: {}", p, e)
            }
            Error::UndefinedVariable(ref name) => {
                write!(out, "Undefined variable: \"${}\"", name)
            }
            Error::ParseError {
                ref file,
                ref pos,
                ref kind,
            } => write!(
                out,
                "{}:{}: Parse error, expected {}",
                file,
                pos,
                kind.as_ref()
                    .map(|k| k.description())
                    .unwrap_or("something else"),
            ),
            // fallback
            ref x => write!(out, "{:?}", x),
        }
    }
}

impl From<io::Error> for Error {
    fn from(e: io::Error) -> Self {
        Error::IoError(e)
    }
}

impl From<FromUtf8Error> for Error {
    fn from(e: FromUtf8Error) -> Self {
        Error::Encoding(e)
    }
}

impl<'a> From<nom::Err<(&[u8], nom::error::ErrorKind)>> for Error {
    fn from(e: nom::Err<(&[u8], nom::error::ErrorKind)>) -> Self {
        Error::S(format!("Parse error: {:?}", e))
    }
}

#[cfg(feature = "clap")]
impl<'a> From<clap::Error> for Error {
    fn from(e: clap::Error) -> Self {
        Error::S(format!("{}", e))
    }
}

/// Position data for a parse error.
///
/// To be usefull for reporting the error to an end user, this
/// contains the position in two forms, both the byte index (an
/// index of the parsed byte slice) and the line number and character
/// position in that line.
#[derive(Debug)]
pub struct ErrPos {
    pub index: usize,
    pub line: usize,
    pub pos: usize,
}

impl ErrPos {
    pub fn pos_of(index: usize, buffer: &[u8]) -> Self {
        let before = &buffer[0..index];
        ErrPos {
            index,
            line: 1 + bytecount::count(before, b'\n'),
            pos: bytecount::num_chars(
                before.rsplit(|c| *c == b'\n').next().unwrap(),
            ),
        }
    }
}
impl fmt::Display for ErrPos {
    fn fmt(&self, out: &mut fmt::Formatter) -> fmt::Result {
        self.line.fmt(out)?;
        out.write_str(":")?;
        self.pos.fmt(out)
    }
}