view rust/hg-core/src/revlog/path_encode.rs @ 46243:63c923fd7fa8

setup: when possible, build and bundle man pages

This makes it so the manual pages are built as part of the Python
build, and includes them in any wheel generated. This should make
Python wheels a much more useful and complete way of distributing
Mercurial binaries.

Differential Revision: https://phab.mercurial-scm.org/D9640

use crypto::digest::Digest;
use crypto::sha1::Sha1;

#[derive(PartialEq, Debug)]
#[allow(non_camel_case_types)]
enum path_state {
    START, /* first byte of a path component */
    A,     /* "AUX" */
    AU,
    THIRD, /* third of a 3-byte sequence, e.g. "AUX", "NUL" */
    C,     /* "CON" or "COMn" */
    CO,
    COMLPT, /* "COM" or "LPT" */
    COMLPTn,
    L,
    LP,
    N,
    NU,
    P, /* "PRN" */
    PR,
    LDOT, /* leading '.' */
    DOT,  /* '.' in a non-leading position */
    H,    /* ".h" */
    HGDI, /* ".hg", ".d", or ".i" */
    SPACE,
    DEFAULT, /* byte of a path component after the first */
}

/* state machine for dir-encoding */
#[allow(non_camel_case_types)]
enum dir_state {
    DDOT,
    DH,
    DHGDI,
    DDEFAULT,
}

fn inset(bitset: &[u32; 8], c: u8) -> bool {
    bitset[(c as usize) >> 5] & (1 << (c & 31)) != 0
}

fn charcopy(dest: Option<&mut [u8]>, destlen: &mut usize, c: u8) {
    if let Some(slice) = dest {
        slice[*destlen] = c
    }
    *destlen += 1
}

fn memcopy(dest: Option<&mut [u8]>, destlen: &mut usize, src: &[u8]) {
    if let Some(slice) = dest {
        slice[*destlen..*destlen + src.len()].copy_from_slice(src)
    }
    *destlen += src.len();
}

fn rewrap_option<'a, 'b: 'a>(
    x: &'a mut Option<&'b mut [u8]>,
) -> Option<&'a mut [u8]> {
    match x {
        None => None,
        Some(y) => Some(y),
    }
}

fn hexencode<'a>(mut dest: Option<&'a mut [u8]>, destlen: &mut usize, c: u8) {
    let hexdigit = b"0123456789abcdef";
    charcopy(
        rewrap_option(&mut dest),
        destlen,
        hexdigit[(c as usize) >> 4],
    );
    charcopy(dest, destlen, hexdigit[(c as usize) & 15]);
}

/* 3-byte escape: tilde followed by two hex digits */
fn escape3(mut dest: Option<&mut [u8]>, destlen: &mut usize, c: u8) {
    charcopy(rewrap_option(&mut dest), destlen, b'~');
    hexencode(dest, destlen, c);
}

fn encode_dir(mut dest: Option<&mut [u8]>, src: &[u8]) -> usize {
    let mut state = dir_state::DDEFAULT;
    let mut i = 0;
    let mut destlen = 0;

    while i < src.len() {
        match state {
            dir_state::DDOT => match src[i] {
                b'd' | b'i' => {
                    state = dir_state::DHGDI;
                    charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
                    i += 1;
                }
                b'h' => {
                    state = dir_state::DH;
                    charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
                    i += 1;
                }
                _ => {
                    state = dir_state::DDEFAULT;
                }
            },
            dir_state::DH => {
                if src[i] == b'g' {
                    state = dir_state::DHGDI;
                    charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
                    i += 1;
                } else {
                    state = dir_state::DDEFAULT;
                }
            }
            dir_state::DHGDI => {
                if src[i] == b'/' {
                    memcopy(rewrap_option(&mut dest), &mut destlen, b".hg");
                    charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
                    i += 1;
                }
                state = dir_state::DDEFAULT;
            }
            dir_state::DDEFAULT => {
                if src[i] == b'.' {
                    state = dir_state::DDOT
                }
                charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
                i += 1;
            }
        }
    }
    destlen
}

fn _encode(
    twobytes: &[u32; 8],
    onebyte: &[u32; 8],
    mut dest: Option<&mut [u8]>,
    src: &[u8],
    encodedir: bool,
) -> usize {
    let mut state = path_state::START;
    let mut i = 0;
    let mut destlen = 0;
    let len = src.len();

    while i < len {
        match state {
            path_state::START => match src[i] {
                b'/' => {
                    charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
                    i += 1;
                }
                b'.' => {
                    state = path_state::LDOT;
                    escape3(rewrap_option(&mut dest), &mut destlen, src[i]);
                    i += 1;
                }
                b' ' => {
                    state = path_state::DEFAULT;
                    escape3(rewrap_option(&mut dest), &mut destlen, src[i]);
                    i += 1;
                }
                b'a' => {
                    state = path_state::A;
                    charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
                    i += 1;
                }
                b'c' => {
                    state = path_state::C;
                    charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
                    i += 1;
                }
                b'l' => {
                    state = path_state::L;
                    charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
                    i += 1;
                }
                b'n' => {
                    state = path_state::N;
                    charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
                    i += 1;
                }
                b'p' => {
                    state = path_state::P;
                    charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
                    i += 1;
                }
                _ => {
                    state = path_state::DEFAULT;
                }
            },
            path_state::A => {
                if src[i] == b'u' {
                    state = path_state::AU;
                    charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
                    i += 1;
                } else {
                    state = path_state::DEFAULT;
                }
            }
            path_state::AU => {
                if src[i] == b'x' {
                    state = path_state::THIRD;
                    i += 1;
                } else {
                    state = path_state::DEFAULT;
                }
            }
            path_state::THIRD => {
                state = path_state::DEFAULT;
                match src[i] {
                    b'.' | b'/' | b'\0' => escape3(
                        rewrap_option(&mut dest),
                        &mut destlen,
                        src[i - 1],
                    ),
                    _ => i -= 1,
                }
            }
            path_state::C => {
                if src[i] == b'o' {
                    state = path_state::CO;
                    charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
                    i += 1;
                } else {
                    state = path_state::DEFAULT;
                }
            }
            path_state::CO => {
                if src[i] == b'm' {
                    state = path_state::COMLPT;
                    i += 1;
                } else if src[i] == b'n' {
                    state = path_state::THIRD;
                    i += 1;
                } else {
                    state = path_state::DEFAULT;
                }
            }
            path_state::COMLPT => {
                if src[i] >= b'1' && src[i] <= b'9' {
                    state = path_state::COMLPTn;
                    i += 1;
                } else {
                    state = path_state::DEFAULT;
                    charcopy(
                        rewrap_option(&mut dest),
                        &mut destlen,
                        src[i - 1],
                    );
                }
            }
            path_state::COMLPTn => {
                state = path_state::DEFAULT;
                match src[i] {
                    b'.' | b'/' | b'\0' => {
                        escape3(
                            rewrap_option(&mut dest),
                            &mut destlen,
                            src[i - 2],
                        );
                        charcopy(
                            rewrap_option(&mut dest),
                            &mut destlen,
                            src[i - 1],
                        );
                    }
                    _ => {
                        memcopy(
                            rewrap_option(&mut dest),
                            &mut destlen,
                            &src[i - 2..i],
                        );
                    }
                }
            }
            path_state::L => {
                if src[i] == b'p' {
                    state = path_state::LP;
                    charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
                    i += 1;
                } else {
                    state = path_state::DEFAULT;
                }
            }
            path_state::LP => {
                if src[i] == b't' {
                    state = path_state::COMLPT;
                    i += 1;
                } else {
                    state = path_state::DEFAULT;
                }
            }
            path_state::N => {
                if src[i] == b'u' {
                    state = path_state::NU;
                    charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
                    i += 1;
                } else {
                    state = path_state::DEFAULT;
                }
            }
            path_state::NU => {
                if src[i] == b'l' {
                    state = path_state::THIRD;
                    i += 1;
                } else {
                    state = path_state::DEFAULT;
                }
            }
            path_state::P => {
                if src[i] == b'r' {
                    state = path_state::PR;
                    charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
                    i += 1;
                } else {
                    state = path_state::DEFAULT;
                }
            }
            path_state::PR => {
                if src[i] == b'n' {
                    state = path_state::THIRD;
                    i += 1;
                } else {
                    state = path_state::DEFAULT;
                }
            }
            path_state::LDOT => match src[i] {
                b'd' | b'i' => {
                    state = path_state::HGDI;
                    charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
                    i += 1;
                }
                b'h' => {
                    state = path_state::H;
                    charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
                    i += 1;
                }
                _ => {
                    state = path_state::DEFAULT;
                }
            },
            path_state::DOT => match src[i] {
                b'/' | b'\0' => {
                    state = path_state::START;
                    memcopy(rewrap_option(&mut dest), &mut destlen, b"~2e");
                    charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
                    i += 1;
                }
                b'd' | b'i' => {
                    state = path_state::HGDI;
                    charcopy(rewrap_option(&mut dest), &mut destlen, b'.');
                    charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
                    i += 1;
                }
                b'h' => {
                    state = path_state::H;
                    memcopy(rewrap_option(&mut dest), &mut destlen, b".h");
                    i += 1;
                }
                _ => {
                    state = path_state::DEFAULT;
                    charcopy(rewrap_option(&mut dest), &mut destlen, b'.');
                }
            },
            path_state::H => {
                if src[i] == b'g' {
                    state = path_state::HGDI;
                    charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
                    i += 1;
                } else {
                    state = path_state::DEFAULT;
                }
            }
            path_state::HGDI => {
                if src[i] == b'/' {
                    state = path_state::START;
                    if encodedir {
                        memcopy(
                            rewrap_option(&mut dest),
                            &mut destlen,
                            b".hg",
                        );
                    }
                    charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
                    i += 1
                } else {
                    state = path_state::DEFAULT;
                }
            }
            path_state::SPACE => match src[i] {
                b'/' | b'\0' => {
                    state = path_state::START;
                    memcopy(rewrap_option(&mut dest), &mut destlen, b"~20");
                    charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
                    i += 1;
                }
                _ => {
                    state = path_state::DEFAULT;
                    charcopy(rewrap_option(&mut dest), &mut destlen, b' ');
                }
            },
            path_state::DEFAULT => {
                while i != len && inset(onebyte, src[i]) {
                    charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
                    i += 1;
                }
                if i == len {
                    break;
                }
                match src[i] {
                    b'.' => {
                        state = path_state::DOT;
                        i += 1
                    }
                    b' ' => {
                        state = path_state::SPACE;
                        i += 1
                    }
                    b'/' => {
                        state = path_state::START;
                        charcopy(rewrap_option(&mut dest), &mut destlen, b'/');
                        i += 1;
                    }
                    _ => {
                        if inset(onebyte, src[i]) {
                            loop {
                                charcopy(
                                    rewrap_option(&mut dest),
                                    &mut destlen,
                                    src[i],
                                );
                                i += 1;
                                if !(i < len && inset(onebyte, src[i])) {
                                    break;
                                }
                            }
                        } else if inset(twobytes, src[i]) {
                            let c = src[i];
                            i += 1;
                            charcopy(
                                rewrap_option(&mut dest),
                                &mut destlen,
                                b'_',
                            );
                            charcopy(
                                rewrap_option(&mut dest),
                                &mut destlen,
                                if c == b'_' { b'_' } else { c + 32 },
                            );
                        } else {
                            escape3(
                                rewrap_option(&mut dest),
                                &mut destlen,
                                src[i],
                            );
                            i += 1;
                        }
                    }
                }
            }
        }
    }
    match state {
        path_state::START => (),
        path_state::A => (),
        path_state::AU => (),
        path_state::THIRD => {
            escape3(rewrap_option(&mut dest), &mut destlen, src[i - 1])
        }
        path_state::C => (),
        path_state::CO => (),
        path_state::COMLPT => {
            charcopy(rewrap_option(&mut dest), &mut destlen, src[i - 1])
        }
        path_state::COMLPTn => {
            escape3(rewrap_option(&mut dest), &mut destlen, src[i - 2]);
            charcopy(rewrap_option(&mut dest), &mut destlen, src[i - 1]);
        }
        path_state::L => (),
        path_state::LP => (),
        path_state::N => (),
        path_state::NU => (),
        path_state::P => (),
        path_state::PR => (),
        path_state::LDOT => (),
        path_state::DOT => {
            memcopy(rewrap_option(&mut dest), &mut destlen, b"~2e");
        }
        path_state::H => (),
        path_state::HGDI => (),
        path_state::SPACE => {
            memcopy(rewrap_option(&mut dest), &mut destlen, b"~20");
        }
        path_state::DEFAULT => (),
    };
    destlen
}

fn basic_encode(dest: Option<&mut [u8]>, src: &[u8]) -> usize {
    let twobytes: [u32; 8] = [0, 0, 0x87ff_fffe, 0, 0, 0, 0, 0];
    let onebyte: [u32; 8] =
        [1, 0x2bff_3bfa, 0x6800_0001, 0x2fff_ffff, 0, 0, 0, 0];
    _encode(&twobytes, &onebyte, dest, src, true)
}

const MAXSTOREPATHLEN: usize = 120;

fn lower_encode(mut dest: Option<&mut [u8]>, src: &[u8]) -> usize {
    let onebyte: [u32; 8] =
        [1, 0x2bff_fbfb, 0xe800_0001, 0x2fff_ffff, 0, 0, 0, 0];
    let lower: [u32; 8] = [0, 0, 0x07ff_fffe, 0, 0, 0, 0, 0];
    let mut destlen = 0;
    for c in src {
        if inset(&onebyte, *c) {
            charcopy(rewrap_option(&mut dest), &mut destlen, *c)
        } else if inset(&lower, *c) {
            charcopy(rewrap_option(&mut dest), &mut destlen, *c + 32)
        } else {
            escape3(rewrap_option(&mut dest), &mut destlen, *c)
        }
    }
    destlen
}

fn aux_encode(dest: Option<&mut [u8]>, src: &[u8]) -> usize {
    let twobytes = [0; 8];
    let onebyte: [u32; 8] = [!0, 0xffff_3ffe, !0, !0, !0, !0, !0, !0];
    _encode(&twobytes, &onebyte, dest, src, false)
}

fn hash_mangle(src: &[u8], sha: &[u8]) -> Vec<u8> {
    let dirprefixlen = 8;
    let maxshortdirslen = 68;
    let mut destlen = 0;

    let last_slash = src.iter().rposition(|b| *b == b'/');
    let last_dot: Option<usize> = {
        let s = last_slash.unwrap_or(0);
        src[s..]
            .iter()
            .rposition(|b| *b == b'.')
            .and_then(|i| Some(i + s))
    };

    let mut dest = vec![0; MAXSTOREPATHLEN];
    memcopy(Some(&mut dest), &mut destlen, b"dh/");

    {
        let mut first = true;
        for slice in src[..last_slash.unwrap_or_else(|| src.len())]
            .split(|b| *b == b'/')
        {
            let slice = &slice[..std::cmp::min(slice.len(), dirprefixlen)];
            if destlen + (slice.len() + if first { 0 } else { 1 })
                > maxshortdirslen + 3
            {
                break;
            } else {
                if !first {
                    charcopy(Some(&mut dest), &mut destlen, b'/')
                };
                memcopy(Some(&mut dest), &mut destlen, slice);
                if dest[destlen - 1] == b'.' || dest[destlen - 1] == b' ' {
                    dest[destlen - 1] = b'_'
                }
            }
            first = false;
        }
        if !first {
            charcopy(Some(&mut dest), &mut destlen, b'/');
        }
    }

    let used = destlen + 40 + {
        if let Some(l) = last_dot {
            src.len() - l
        } else {
            0
        }
    };

    if MAXSTOREPATHLEN > used {
        let slop = MAXSTOREPATHLEN - used;
        let basenamelen = match last_slash {
            Some(l) => src.len() - l - 1,
            None => src.len(),
        };
        let basenamelen = std::cmp::min(basenamelen, slop);
        if basenamelen > 0 {
            let start = match last_slash {
                Some(l) => l + 1,
                None => 0,
            };
            memcopy(
                Some(&mut dest),
                &mut destlen,
                &src[start..][..basenamelen],
            )
        }
    }
    for c in sha {
        hexencode(Some(&mut dest), &mut destlen, *c);
    }
    if let Some(l) = last_dot {
        memcopy(Some(&mut dest), &mut destlen, &src[l..]);
    }
    if destlen == dest.len() {
        dest
    } else {
        // sometimes the path are shorter than MAXSTOREPATHLEN
        dest[..destlen].to_vec()
    }
}

const MAXENCODE: usize = 4096 * 4;
fn hash_encode(src: &[u8]) -> Vec<u8> {
    let dired = &mut [0; MAXENCODE];
    let lowered = &mut [0; MAXENCODE];
    let auxed = &mut [0; MAXENCODE];
    let baselen = (src.len() - 5) * 3;
    if baselen >= MAXENCODE {
        panic!("path_encode::hash_encore: string too long: {}", baselen)
    };
    let dirlen = encode_dir(Some(&mut dired[..]), src);
    let sha = {
        let mut hasher = Sha1::new();
        hasher.input(&dired[..dirlen]);
        let mut hash = vec![0; 20];
        hasher.result(&mut hash);
        hash
    };
    let lowerlen = lower_encode(Some(&mut lowered[..]), &dired[..dirlen][5..]);
    let auxlen = aux_encode(Some(&mut auxed[..]), &lowered[..lowerlen]);
    hash_mangle(&auxed[..auxlen], &sha)
}

pub fn path_encode(path: &[u8]) -> Vec<u8> {
    let newlen = if path.len() <= MAXSTOREPATHLEN {
        basic_encode(None, path)
    } else {
        MAXSTOREPATHLEN + 1
    };
    if newlen <= MAXSTOREPATHLEN {
        if newlen == path.len() {
            path.to_vec()
        } else {
            let mut res = vec![0; newlen];
            basic_encode(Some(&mut res), path);
            res
        }
    } else {
        hash_encode(&path)
    }
}