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rust-changelog: introducing an intermediate `ChangelogEntry`...
rust-changelog: introducing an intermediate `ChangelogEntry` Before this change, client code needing to extract, e.g, the Node ID and the description from a changeset had no other choice than calling both `entry_for_rev()` and `data_for_rev()`. This duplicates some (limited) computation, and more importantly imposes bad hygiene for client code: at some point of developement, the client code would have to pass over both entry and data in its internal layers, which at some point of development would raise the question whether they are consistent. We introduce the intermediate `ChangelogEntry` from which both conversion to the generic `RevlogEntry` and extraction of `ChangelogRevisionData` are possible. It might grow some convenience methods in the future. We keep the `data_for_rev()` method of `Changelog` for compatibility, pointing users at the more powerful alternative.
Arseniy Alekseyev - - Load All Authors

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r51264:3f513754 stable
r51268:841b13e6 default
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path_encode.rs
622 lines | 17.8 KiB | application/rls-services+xml | RustLexer
/ rust / hg-core / src / revlog / path_encode.rs
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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;
} 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_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)
);
}
}