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Diffstat (limited to 'third_party/rust/uuid/src/error.rs')
| -rw-r--r-- | third_party/rust/uuid/src/error.rs | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/third_party/rust/uuid/src/error.rs b/third_party/rust/uuid/src/error.rs new file mode 100644 index 0000000000..e9aecbf82c --- /dev/null +++ b/third_party/rust/uuid/src/error.rs @@ -0,0 +1,172 @@ +use crate::std::fmt; + +/// A general error that can occur when working with UUIDs. +#[derive(Clone, Debug, Eq, Hash, PartialEq)] +pub struct Error(pub(crate) ErrorKind); + +#[derive(Clone, Debug, Eq, Hash, PartialEq)] +pub(crate) enum ErrorKind { + /// Invalid character in the [`Uuid`] string. + /// + /// [`Uuid`]: ../struct.Uuid.html + Char { character: char, index: usize }, + /// A simple [`Uuid`] didn't contain 32 characters. + /// + /// [`Uuid`]: ../struct.Uuid.html + SimpleLength { len: usize }, + /// A byte array didn't contain 16 bytes + ByteLength { len: usize }, + /// A hyphenated [`Uuid`] didn't contain 5 groups + /// + /// [`Uuid`]: ../struct.Uuid.html + GroupCount { count: usize }, + /// A hyphenated [`Uuid`] had a group that wasn't the right length + /// + /// [`Uuid`]: ../struct.Uuid.html + GroupLength { + group: usize, + len: usize, + index: usize, + }, + /// The input was not a valid UTF8 string + InvalidUTF8, + /// Some other error occurred. + Other, +} + +/// A string that is guaranteed to fail to parse to a [`Uuid`]. +/// +/// This type acts as a lightweight error indicator, suggesting +/// that the string cannot be parsed but offering no error +/// details. To get details, use `InvalidUuid::into_err`. +/// +/// [`Uuid`]: ../struct.Uuid.html +#[derive(Clone, Debug, Eq, Hash, PartialEq)] +pub struct InvalidUuid<'a>(pub(crate) &'a [u8]); + +impl<'a> InvalidUuid<'a> { + /// Converts the lightweight error type into detailed diagnostics. + pub fn into_err(self) -> Error { + // Check whether or not the input was ever actually a valid UTF8 string + let input_str = match std::str::from_utf8(self.0) { + Ok(s) => s, + Err(_) => return Error(ErrorKind::InvalidUTF8), + }; + + let (uuid_str, offset, simple) = match input_str.as_bytes() { + [b'{', s @ .., b'}'] => (s, 1, false), + [b'u', b'r', b'n', b':', b'u', b'u', b'i', b'd', b':', s @ ..] => { + (s, "urn:uuid:".len(), false) + } + s => (s, 0, true), + }; + + let mut hyphen_count = 0; + let mut group_bounds = [0; 4]; + + // SAFETY: the byte array came from a valid utf8 string, + // and is aligned along char boundaries. + let uuid_str = unsafe { std::str::from_utf8_unchecked(uuid_str) }; + + for (index, character) in uuid_str.char_indices() { + let byte = character as u8; + if character as u32 - byte as u32 > 0 { + // Multibyte char + return Error(ErrorKind::Char { + character, + index: index + offset + 1, + }); + } else if byte == b'-' { + // While we search, also count group breaks + if hyphen_count < 4 { + group_bounds[hyphen_count] = index; + } + hyphen_count += 1; + } else if !matches!(byte, b'0'..=b'9' | b'a'..=b'f' | b'A'..=b'F') { + // Non-hex char + return Error(ErrorKind::Char { + character: byte as char, + index: index + offset + 1, + }); + } + } + + if hyphen_count == 0 && simple { + // This means that we tried and failed to parse a simple uuid. + // Since we verified that all the characters are valid, this means + // that it MUST have an invalid length. + Error(ErrorKind::SimpleLength { + len: input_str.len(), + }) + } else if hyphen_count != 4 { + // We tried to parse a hyphenated variant, but there weren't + // 5 groups (4 hyphen splits). + Error(ErrorKind::GroupCount { + count: hyphen_count + 1, + }) + } else { + // There are 5 groups, one of them has an incorrect length + const BLOCK_STARTS: [usize; 5] = [0, 9, 14, 19, 24]; + for i in 0..4 { + if group_bounds[i] != BLOCK_STARTS[i + 1] - 1 { + return Error(ErrorKind::GroupLength { + group: i, + len: group_bounds[i] - BLOCK_STARTS[i], + index: offset + BLOCK_STARTS[i] + 1, + }); + } + } + + // The last group must be too long + Error(ErrorKind::GroupLength { + group: 4, + len: input_str.len() - BLOCK_STARTS[4], + index: offset + BLOCK_STARTS[4] + 1, + }) + } + } +} + +// NOTE: This impl is part of the public API. Breaking changes to it should be carefully considered +impl fmt::Display for Error { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + match self.0 { + ErrorKind::Char { + character, index, .. + } => { + write!(f, "invalid character: expected an optional prefix of `urn:uuid:` followed by [0-9a-fA-F-], found `{}` at {}", character, index) + } + ErrorKind::SimpleLength { len } => { + write!( + f, + "invalid length: expected length 32 for simple format, found {}", + len + ) + } + ErrorKind::ByteLength { len } => { + write!(f, "invalid length: expected 16 bytes, found {}", len) + } + ErrorKind::GroupCount { count } => { + write!(f, "invalid group count: expected 5, found {}", count) + } + ErrorKind::GroupLength { group, len, .. } => { + let expected = [8, 4, 4, 4, 12][group]; + write!( + f, + "invalid group length in group {}: expected {}, found {}", + group, expected, len + ) + } + ErrorKind::InvalidUTF8 => write!(f, "non-UTF8 input"), + ErrorKind::Other => write!(f, "failed to parse a UUID"), + } + } +} + +#[cfg(feature = "std")] +mod std_support { + use super::*; + use crate::std::error; + + impl error::Error for Error {} +} |