| @@ -0,0 +1,110 @@ |
| 1 | +pub mod undo { |
| 2 | + use bstr::{BStr, BString}; |
| 3 | + use quick_error::quick_error; |
| 4 | + |
| 5 | + quick_error! { |
| 6 | + #[derive(Debug)] |
| 7 | + pub enum Error { |
| 8 | + InvalidInput { message: String, input: BString } { |
| 9 | + display("{}: {:?}", message, input) |
| 10 | + } |
| 11 | + UnsupportedEscapeByte { byte: u8, input: BString } { |
| 12 | + display("Invalid escaped value {} in input {:?}", byte, input) |
| 13 | + } |
| 14 | + } |
| 15 | + } |
| 16 | + |
| 17 | + impl Error { |
| 18 | + pub(crate) fn new(message: impl ToString, input: &BStr) -> Error { |
| 19 | + Error::InvalidInput { |
| 20 | + message: message.to_string(), |
| 21 | + input: input.into(), |
| 22 | + } |
| 23 | + } |
| 24 | + } |
| 25 | +} |
| 26 | + |
| 27 | +use std::{borrow::Cow, io::Read}; |
| 28 | + |
| 29 | +use bstr::{BStr, BString, ByteSlice}; |
| 30 | + |
| 31 | +/// Unquote the given ansi-c quoted `input` string. |
| 32 | +/// |
| 33 | +/// The `input` is returned unaltered if it doesn't start with a `"` character to indicate |
| 34 | +/// quotation, otherwise a new unqoted string will always be allocated. |
| 35 | +/// |
| 36 | +/// See [the tests][tests] for quotation examples. |
| 37 | +/// |
| 38 | +/// [tests]: https://github.com/Byron/gitoxide/blob/e355b4ad133075152312816816af5ce72cf79cff/git-odb/src/alternate/unquote.rs#L110-L118 |
| 39 | +pub fn undo(input: &BStr) -> Result<Cow<'_, BStr>, undo::Error> { |
| 40 | + if !input.starts_with(b"\"") { |
| 41 | + return Ok(input.into()); |
| 42 | + } |
| 43 | + if input.len() < 2 { |
| 44 | + return Err(undo::Error::new("Input must be surrounded by double quotes", input)); |
| 45 | + } |
| 46 | + let original = input.as_bstr(); |
| 47 | + let mut input = &input[1..]; |
| 48 | + let mut out = BString::default(); |
| 49 | + fn consume_one_past(input: &mut &BStr, position: usize) -> Result<u8, undo::Error> { |
| 50 | + *input = input |
| 51 | + .get(position + 1..) |
| 52 | + .ok_or_else(|| undo::Error::new("Unexpected end of input", input))? |
| 53 | + .as_bstr(); |
| 54 | + let next = input[0]; |
| 55 | + *input = input.get(1..).unwrap_or_default().as_bstr(); |
| 56 | + Ok(next) |
| 57 | + } |
| 58 | + loop { |
| 59 | + match input.find_byteset(b"\"\\") { |
| 60 | + Some(position) => { |
| 61 | + out.extend_from_slice(&input[..position]); |
| 62 | + match input[position] { |
| 63 | + b'"' => break, |
| 64 | + b'\\' => { |
| 65 | + let next = consume_one_past(&mut input, position)?; |
| 66 | + match next { |
| 67 | + b'n' => out.push(b'\n'), |
| 68 | + b'r' => out.push(b'\r'), |
| 69 | + b't' => out.push(b'\t'), |
| 70 | + b'a' => out.push(7), |
| 71 | + b'b' => out.push(8), |
| 72 | + b'v' => out.push(0xb), |
| 73 | + b'f' => out.push(0xc), |
| 74 | + b'"' => out.push(b'"'), |
| 75 | + b'\\' => out.push(b'\\'), |
| 76 | + b'0' | b'1' | b'2' | b'3' => { |
| 77 | + let mut buf = [next; 3]; |
| 78 | + input |
| 79 | + .get(..2) |
| 80 | + .ok_or_else(|| { |
| 81 | + undo::Error::new( |
| 82 | + "Unexpected end of input when fetching two more octal bytes", |
| 83 | + input, |
| 84 | + ) |
| 85 | + })? |
| 86 | + .read_exact(&mut buf[1..]) |
| 87 | + .expect("impossible to fail as numbers match"); |
| 88 | + let byte = btoi::btou_radix(&buf, 8).map_err(|e| undo::Error::new(e, original))?; |
| 89 | + out.push(byte); |
| 90 | + input = &input[2..]; |
| 91 | + } |
| 92 | + _ => { |
| 93 | + return Err(undo::Error::UnsupportedEscapeByte { |
| 94 | + byte: next, |
| 95 | + input: original.into(), |
| 96 | + }) |
| 97 | + } |
| 98 | + } |
| 99 | + } |
| 100 | + _ => unreachable!("cannot find character that we didn't search for"), |
| 101 | + } |
| 102 | + } |
| 103 | + None => { |
| 104 | + out.extend_from_slice(input); |
| 105 | + break; |
| 106 | + } |
| 107 | + } |
| 108 | + } |
| 109 | + Ok(out.into()) |
| 110 | +} |