comparison rust/hg-core/src/revlog/node.rs @ 46033:88e741bf2d93

rust: use NodePrefix::from_hex instead of hex::decode directly

This adds support for prefixes with an odd number of hex digits.

Differential Revision: https://phab.mercurial-scm.org/D9490

46032:8d6164098782

//!
//! In Mercurial code base, it is customary to call "a node" the binary SHA
//! of a revision.

use hex::{self, FromHex, FromHexError};

/// The length in bytes of a `Node`
///
/// This constant is meant to ease refactors of this module, and
/// are private so that calling code does not expect all nodes have

    fn from(data: NodeData) -> Node {
        Node { data }
    }
}

#[derive(Debug, PartialEq)]
pub enum NodeError {
    ExactLengthRequired(usize, String),
    PrefixTooLong(String),
    HexError(FromHexError, String),

    ///
    /// Exact length is required.
    ///
    /// To be used in FFI and I/O only, in order to facilitate future
    /// changes of hash format.
    pub fn from_hex(hex: &str) -> Result<Node, NodeError> {
        Ok(NodeData::from_hex(hex)
            .map_err(|e| NodeError::from((e, hex)))?
            .into())
    }

    /// Convert to hexadecimal string representation

    pub fn as_bytes(&self) -> &[u8] {
        &self.data
    }
}

impl<T: AsRef<str>> From<(FromHexError, T)> for NodeError {
    fn from(err_offender: (FromHexError, T)) -> Self {
        let (err, offender) = err_offender;
        match err {
            FromHexError::InvalidStringLength => {
                NodeError::ExactLengthRequired(
                    NODE_NYBBLES_LENGTH,
                    offender.as_ref().to_owned(),
                )
            }
            _ => NodeError::HexError(err, offender.as_ref().to_owned()),
        }
    }
}

/// The beginning of a binary revision SHA.

            ));
        }

        let is_odd = len % 2 == 1;
        let even_part = if is_odd { &hex[..len - 1] } else { hex };
        let mut buf: Vec<u8> = Vec::from_hex(&even_part)
            .map_err(|e| (e, String::from_utf8_lossy(hex)))?;

        if is_odd {
            let latest_char = char::from(hex[len - 1]);
            let latest_nybble = latest_char.to_digit(16).ok_or_else(|| {
                (
                    FromHexError::InvalidHexCharacter {
                        c: latest_char,
                        index: len - 1,
                    },
                    String::from_utf8_lossy(hex),
                )
            })? as u8;
            buf.push(latest_nybble << 4);
        }
        Ok(NodePrefix { buf, is_odd })

            is_odd: false,
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    fn sample_node() -> Node {

        ]);
        data.into()
    }

    /// Pad an hexadecimal string to reach `NODE_NYBBLES_LENGTH`
    ///
    /// The padding is made with zeros
    pub fn hex_pad_right(hex: &str) -> String {
        let mut res = hex.to_string();
        while res.len() < NODE_NYBBLES_LENGTH {
            res.push('0');

46033:88e741bf2d93

//!
//! In Mercurial code base, it is customary to call "a node" the binary SHA
//! of a revision.

use hex::{self, FromHex, FromHexError};
use std::convert::{TryFrom, TryInto};

/// The length in bytes of a `Node`
///
/// This constant is meant to ease refactors of this module, and
/// are private so that calling code does not expect all nodes have

    fn from(data: NodeData) -> Node {
        Node { data }
    }
}

/// Return an error if the slice has an unexpected length
impl<'a> TryFrom<&'a [u8]> for &'a Node {
    type Error = std::array::TryFromSliceError;

    #[inline]
    fn try_from(bytes: &'a [u8]) -> Result<&'a Node, Self::Error> {
        let data = bytes.try_into()?;
        // Safety: `#[repr(transparent)]` makes it ok to "wrap" the target
        // of a reference to the type of the single field.
        Ok(unsafe { std::mem::transmute::<&NodeData, &Node>(data) })
    }
}

#[derive(Debug, PartialEq)]
pub enum NodeError {
    ExactLengthRequired(usize, String),
    PrefixTooLong(String),
    HexError(FromHexError, String),

    ///
    /// Exact length is required.
    ///
    /// To be used in FFI and I/O only, in order to facilitate future
    /// changes of hash format.
    pub fn from_hex(hex: impl AsRef<[u8]>) -> Result<Node, NodeError> {
        Ok(NodeData::from_hex(hex.as_ref())
            .map_err(|e| NodeError::from((e, hex)))?
            .into())
    }

    /// Convert to hexadecimal string representation

    pub fn as_bytes(&self) -> &[u8] {
        &self.data
    }
}

impl<T: AsRef<[u8]>> From<(FromHexError, T)> for NodeError {
    fn from(err_offender: (FromHexError, T)) -> Self {
        let (err, offender) = err_offender;
        let offender = String::from_utf8_lossy(offender.as_ref()).into_owned();
        match err {
            FromHexError::InvalidStringLength => {
                NodeError::ExactLengthRequired(NODE_NYBBLES_LENGTH, offender)
            }
            _ => NodeError::HexError(err, offender),
        }
    }
}

/// The beginning of a binary revision SHA.

            ));
        }

        let is_odd = len % 2 == 1;
        let even_part = if is_odd { &hex[..len - 1] } else { hex };
        let mut buf: Vec<u8> =
            Vec::from_hex(&even_part).map_err(|e| (e, hex))?;

        if is_odd {
            let latest_char = char::from(hex[len - 1]);
            let latest_nybble = latest_char.to_digit(16).ok_or_else(|| {
                (
                    FromHexError::InvalidHexCharacter {
                        c: latest_char,
                        index: len - 1,
                    },
                    hex,
                )
            })? as u8;
            buf.push(latest_nybble << 4);
        }
        Ok(NodePrefix { buf, is_odd })

            is_odd: false,
        }
    }
}

impl PartialEq<Node> for NodePrefixRef<'_> {
    fn eq(&self, other: &Node) -> bool {
        !self.is_odd && self.buf == other.data
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    fn sample_node() -> Node {

        ]);
        data.into()
    }

    /// Pad an hexadecimal string to reach `NODE_NYBBLES_LENGTH`
    ///check_hash
    /// The padding is made with zeros
    pub fn hex_pad_right(hex: &str) -> String {
        let mut res = hex.to_string();
        while res.len() < NODE_NYBBLES_LENGTH {
            res.push('0');