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error.rs
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error.rs
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use crate::css::Value;
use crate::parser::{ParseError, Span};
use std::convert::From;
use std::path::PathBuf;
use std::str::from_utf8;
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 { msg: String, pos: ErrPos },
S(String),
UndefinedVariable(String),
}
impl std::error::Error for Error {}
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: \"${}\"", name)
}
Error::ParseError { ref msg, ref pos } => {
let line_no = pos.line_no.to_string();
write!(
out,
"{0:lnw$} ,\
\n{ln} | {line}\
\n{0:lnw$} |{0:>lpos$}^ {msg}\
\n{0:lnw$} '",
"",
line = pos.line,
msg = msg,
ln = line_no,
lnw = line_no.len(),
lpos = pos.line_pos,
)
}
// fallback
ref x => write!(out, "{:?}", x),
}
}
}
impl<'a> From<ParseError<'a>> for Error {
fn from(err: ParseError) -> Self {
Error::ParseError {
msg: format!("Parse error: {:?}", err.err),
pos: ErrPos::magic_pos(err.span),
}
}
}
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)
}
}
/// Position data for a parse error.
#[derive(Debug)]
pub struct ErrPos {
line: String,
line_no: usize,
line_pos: usize,
}
impl ErrPos {
fn magic_pos(span: Span) -> Self {
use std::slice;
let self_bytes = span.fragment();
let self_ptr = self_bytes.as_ptr();
let offset = span.get_column() - 1;
let the_line = unsafe {
assert!(
offset <= isize::max_value() as usize,
"offset is too big"
);
let orig_input_ptr = self_ptr.offset(-(offset as isize));
slice::from_raw_parts(
orig_input_ptr,
offset + span.fragment().len(),
)
};
let the_line = the_line
.split(|c| *c == b'\n')
.next()
.and_then(|s| from_utf8(s).ok())
.unwrap_or("<<failed to display line>>");
ErrPos {
line: the_line.to_string(),
line_no: span.location_line() as usize,
line_pos: span.get_utf8_column(),
}
}
}