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rust: make `Revision` a newtype...
rust: make `Revision` a newtype This change is the one we've been building towards during this series. The aim is to make `Revision` mean more than a simple integer, holding the information that it is valid for a given revlog index. While this still allows for programmer error, since creating a revision directly and querying a different index with a "checked" revision are still possible, the friction created by the newtype will hopefully make us think twice about which type to use. Enough of the Rust ecosystem relies on the newtype pattern to be efficiently optimized away (even compiler in codegen testsĀ¹), so I'm not worried about this being a fundamental problem. [1] https://github.com/rust-lang/rust/blob/7a70647f195f6b0a0f1ebd72b1542ba91a32f43a/tests/codegen/vec-in-place.rs#L47

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path_encode.rs
639 lines | 18.5 KiB | application/rls-services+xml | RustLexer
use sha1::{Digest, Sha1};
#[derive(PartialEq, Debug)]
#[allow(non_camel_case_types)]
#[allow(clippy::upper_case_acronyms)]
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)]
#[allow(clippy::upper_case_acronyms)]
enum dir_state {
DDOT,
DH,
DHGDI,
DDEFAULT,
}
trait Sink {
fn write_byte(&mut self, c: u8);
fn write_bytes(&mut self, c: &[u8]);
}
fn inset(bitset: &[u32; 8], c: u8) -> bool {
bitset[(c as usize) >> 5] & (1 << (c & 31)) != 0
}
const MAXENCODE: usize = 4096 * 4;
struct DestArr<const N: usize> {
buf: [u8; N],
pub len: usize,
}
impl<const N: usize> DestArr<N> {
pub fn create() -> Self {
DestArr {
buf: [0; N],
len: 0,
}
}
pub fn contents(&self) -> &[u8] {
&self.buf[..self.len]
}
}
impl<const N: usize> Sink for DestArr<N> {
fn write_byte(&mut self, c: u8) {
self.buf[self.len] = c;
self.len += 1;
}
fn write_bytes(&mut self, src: &[u8]) {
self.buf[self.len..self.len + src.len()].copy_from_slice(src);
self.len += src.len();
}
}
struct MeasureDest {
pub len: usize,
}
impl Sink for Vec<u8> {
fn write_byte(&mut self, c: u8) {
self.push(c)
}
fn write_bytes(&mut self, src: &[u8]) {
self.extend_from_slice(src)
}
}
impl MeasureDest {
fn create() -> Self {
Self { len: 0 }
}
}
impl Sink for MeasureDest {
fn write_byte(&mut self, _c: u8) {
self.len += 1;
}
fn write_bytes(&mut self, src: &[u8]) {
self.len += src.len();
}
}
fn hexencode(dest: &mut impl Sink, c: u8) {
let hexdigit = b"0123456789abcdef";
dest.write_byte(hexdigit[(c as usize) >> 4]);
dest.write_byte(hexdigit[(c as usize) & 15]);
}
/* 3-byte escape: tilde followed by two hex digits */
fn escape3(dest: &mut impl Sink, c: u8) {
dest.write_byte(b'~');
hexencode(dest, c);
}
fn encode_dir(dest: &mut impl Sink, src: &[u8]) {
let mut state = dir_state::DDEFAULT;
let mut i = 0;
while i < src.len() {
match state {
dir_state::DDOT => match src[i] {
b'd' | b'i' => {
state = dir_state::DHGDI;
dest.write_byte(src[i]);
i += 1;
}
b'h' => {
state = dir_state::DH;
dest.write_byte(src[i]);
i += 1;
}
_ => {
state = dir_state::DDEFAULT;
}
},
dir_state::DH => {
if src[i] == b'g' {
state = dir_state::DHGDI;
dest.write_byte(src[i]);
i += 1;
} else {
state = dir_state::DDEFAULT;
}
}
dir_state::DHGDI => {
if src[i] == b'/' {
dest.write_bytes(b".hg");
dest.write_byte(src[i]);
i += 1;
}
state = dir_state::DDEFAULT;
}
dir_state::DDEFAULT => {
if src[i] == b'.' {
state = dir_state::DDOT
}
dest.write_byte(src[i]);
i += 1;
}
}
}
}
fn _encode(
twobytes: &[u32; 8],
onebyte: &[u32; 8],
dest: &mut impl Sink,
src: &[u8],
encodedir: bool,
) {
let mut state = path_state::START;
let mut i = 0;
let len = src.len();
while i < len {
match state {
path_state::START => match src[i] {
b'/' => {
dest.write_byte(src[i]);
i += 1;
}
b'.' => {
state = path_state::LDOT;
escape3(dest, src[i]);
i += 1;
}
b' ' => {
state = path_state::DEFAULT;
escape3(dest, src[i]);
i += 1;
}
b'a' => {
state = path_state::A;
dest.write_byte(src[i]);
i += 1;
}
b'c' => {
state = path_state::C;
dest.write_byte(src[i]);
i += 1;
}
b'l' => {
state = path_state::L;
dest.write_byte(src[i]);
i += 1;
}
b'n' => {
state = path_state::N;
dest.write_byte(src[i]);
i += 1;
}
b'p' => {
state = path_state::P;
dest.write_byte(src[i]);
i += 1;
}
_ => {
state = path_state::DEFAULT;
}
},
path_state::A => {
if src[i] == b'u' {
state = path_state::AU;
dest.write_byte(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(dest, src[i - 1]),
_ => i -= 1,
}
}
path_state::C => {
if src[i] == b'o' {
state = path_state::CO;
dest.write_byte(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;
dest.write_byte(src[i - 1]);
}
}
path_state::COMLPTn => {
state = path_state::DEFAULT;
match src[i] {
b'.' | b'/' | b'\0' => {
escape3(dest, src[i - 2]);
dest.write_byte(src[i - 1]);
}
_ => {
dest.write_bytes(&src[i - 2..i]);
}
}
}
path_state::L => {
if src[i] == b'p' {
state = path_state::LP;
dest.write_byte(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;
dest.write_byte(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;
dest.write_byte(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;
dest.write_byte(src[i]);
i += 1;
}
b'h' => {
state = path_state::H;
dest.write_byte(src[i]);
i += 1;
}
_ => {
state = path_state::DEFAULT;
}
},
path_state::DOT => match src[i] {
b'/' | b'\0' => {
state = path_state::START;
dest.write_bytes(b"~2e");
dest.write_byte(src[i]);
i += 1;
}
b'd' | b'i' => {
state = path_state::HGDI;
dest.write_byte(b'.');
dest.write_byte(src[i]);
i += 1;
}
b'h' => {
state = path_state::H;
dest.write_bytes(b".h");
i += 1;
}
_ => {
state = path_state::DEFAULT;
dest.write_byte(b'.');
}
},
path_state::H => {
if src[i] == b'g' {
state = path_state::HGDI;
dest.write_byte(src[i]);
i += 1;
} else {
state = path_state::DEFAULT;
}
}
path_state::HGDI => {
if src[i] == b'/' {
state = path_state::START;
if encodedir {
dest.write_bytes(b".hg");
}
dest.write_byte(src[i]);
i += 1
} else {
state = path_state::DEFAULT;
}
}
path_state::SPACE => match src[i] {
b'/' | b'\0' => {
state = path_state::START;
dest.write_bytes(b"~20");
dest.write_byte(src[i]);
i += 1;
}
_ => {
state = path_state::DEFAULT;
dest.write_byte(b' ');
}
},
path_state::DEFAULT => {
while i != len && inset(onebyte, src[i]) {
dest.write_byte(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;
dest.write_byte(b'/');
i += 1;
}
_ => {
if inset(onebyte, src[i]) {
loop {
dest.write_byte(src[i]);
i += 1;
if !(i < len && inset(onebyte, src[i])) {
break;
}
}
} else if inset(twobytes, src[i]) {
let c = src[i];
i += 1;
dest.write_byte(b'_');
dest.write_byte(if c == b'_' {
b'_'
} else {
c + 32
});
} else {
escape3(dest, src[i]);
i += 1;
}
}
}
}
}
}
match state {
path_state::START => (),
path_state::A => (),
path_state::AU => (),
path_state::THIRD => escape3(dest, src[i - 1]),
path_state::C => (),
path_state::CO => (),
path_state::COMLPT => dest.write_byte(src[i - 1]),
path_state::COMLPTn => {
escape3(dest, src[i - 2]);
dest.write_byte(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 => {
dest.write_bytes(b"~2e");
}
path_state::H => (),
path_state::HGDI => (),
path_state::SPACE => {
dest.write_bytes(b"~20");
}
path_state::DEFAULT => (),
}
}
fn basic_encode(dest: &mut impl Sink, src: &[u8]) {
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(dest: &mut impl Sink, src: &[u8]) {
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];
for c in src {
if inset(&onebyte, *c) {
dest.write_byte(*c)
} else if inset(&lower, *c) {
dest.write_byte(*c + 32)
} else {
escape3(dest, *c)
}
}
}
fn aux_encode(dest: &mut impl Sink, src: &[u8]) {
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 last_slash = src.iter().rposition(|b| *b == b'/');
let basename_start = match last_slash {
Some(slash) => slash + 1,
None => 0,
};
let basename = &src[basename_start..];
let ext = match basename.iter().rposition(|b| *b == b'.') {
None => &[],
Some(dot) => &basename[dot..],
};
let mut dest = Vec::with_capacity(MAXSTOREPATHLEN);
dest.write_bytes(b"dh/");
if let Some(last_slash) = last_slash {
for slice in src[..last_slash].split(|b| *b == b'/') {
let slice = &slice[..std::cmp::min(slice.len(), dirprefixlen)];
if dest.len() + slice.len() > maxshortdirslen + 3 {
break;
}
if let Some(last_char) = slice.last() {
if *last_char == b'.' || *last_char == b' ' {
dest.write_bytes(&slice[0..slice.len() - 1]);
dest.write_byte(b'_');
} else {
dest.write_bytes(slice);
}
};
dest.write_byte(b'/');
}
}
let used = dest.len() + 40 + ext.len();
if MAXSTOREPATHLEN > used {
let slop = MAXSTOREPATHLEN - used;
let len = std::cmp::min(basename.len(), slop);
dest.write_bytes(&basename[..len])
}
for c in sha {
hexencode(&mut dest, *c);
}
dest.write_bytes(ext);
dest.shrink_to_fit();
dest
}
fn hash_encode(src: &[u8]) -> Vec<u8> {
let mut dired: DestArr<MAXENCODE> = DestArr::create();
let mut lowered: DestArr<MAXENCODE> = DestArr::create();
let mut auxed: DestArr<MAXENCODE> = DestArr::create();
let baselen = (src.len() - 5) * 3;
if baselen >= MAXENCODE {
panic!("path_encode::hash_encore: string too long: {}", baselen)
};
encode_dir(&mut dired, src);
let sha = Sha1::digest(dired.contents());
lower_encode(&mut lowered, &dired.contents()[5..]);
aux_encode(&mut auxed, lowered.contents());
hash_mangle(auxed.contents(), &sha)
}
pub fn path_encode(path: &[u8]) -> Vec<u8> {
let newlen = if path.len() <= MAXSTOREPATHLEN {
let mut measure = MeasureDest::create();
basic_encode(&mut measure, path);
measure.len
} else {
return hash_encode(path);
};
if newlen <= MAXSTOREPATHLEN {
if newlen == path.len() {
path.to_vec()
} else {
let mut dest = Vec::with_capacity(newlen);
basic_encode(&mut dest, path);
assert!(dest.len() == newlen);
dest
}
} else {
hash_encode(path)
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::utils::hg_path::HgPathBuf;
#[test]
fn test_dirname_ends_with_underscore() {
let input = b"data/dir1234.foo/ABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJ.i";
let expected = b"dh/dir1234_/abcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghij.if2e9ce59e095eff5f8f334dc809e65606a0aa50b.i";
let res = path_encode(input);
assert_eq!(
HgPathBuf::from_bytes(&res),
HgPathBuf::from_bytes(expected)
);
}
#[test]
fn test_long_filename_at_root() {
let input = b"data/ABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJ.i";
let expected = b"dh/abcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghij.i708243a2237a7afae259ea3545a72a2ef11c247b.i";
let res = path_encode(input);
assert_eq!(
HgPathBuf::from_bytes(&res),
HgPathBuf::from_bytes(expected)
);
}
}