use git_object::{owned, SHA1_SIZE};use std::io; const _TYPE_EXT1: u8 = 0;const COMMIT: u8 = 1;const TREE: u8 = 2;const BLOB: u8 = 3;const TAG: u8 = 4;const _TYPE_EXT2: u8 = 5;const OFS_DELTA: u8 = 6;const REF_DELTA: u8 = 7; #[derive(PartialEq, Eq, Debug, Hash, Ord, PartialOrd, Clone)]#[cfg_attr(feature = "serde1", derive(serde::Serialize, serde::Deserialize))]pub struct Entry { pub header: Header, /// The decompressed size of the object in bytes pub decompressed_size: u64, /// absolute offset to compressed object data in the pack, just behind the header pub data_offset: u64,} #[derive(PartialEq, Eq, Debug, Hash, Ord, PartialOrd, Clone, Copy)]#[cfg_attr(feature = "serde1", derive(serde::Serialize, serde::Deserialize))]pub enum Header { Commit, Tree, Blob, Tag, /// An object within this pack if the LSB encoded offset would be larger than 20 bytes /// Alternatively an object stored in the repository, if this is a thin pack RefDelta { oid: owned::Id, }, /// The offset into the pack at which to find the base object header OfsDelta { pack_offset: u64, },} impl Header { pub fn to_kind(&self) -> Option<git_object::Kind> { use git_object::Kind::*; Some(match self { Header::Tree => Tree, Header::Blob => Blob, Header::Commit => Commit, Header::Tag => Tag, Header::RefDelta { .. } | Header::OfsDelta { .. } => return None, }) } pub fn is_delta(&self) -> bool { match self { Header::OfsDelta { .. } | Header::RefDelta { .. } => true, _ => false, } }} #[inline]fn leb64decode(d: &[u8]) -> (u64, usize) { let mut i = 0; let mut c = d[i]; i += 1; let mut value = c as u64 & 0x7f; while c & 0x80 != 0 { c = d[i]; i += 1; value += 1; value = (value << 7) + (c as u64 & 0x7f) } (value, i)} #[inline]fn streaming_leb64decode(mut r: impl io::Read) -> Result<(u64, usize), io::Error> { let mut b = [0u8; 1]; let mut i = 0; r.read_exact(&mut b)?; i += 1; let mut value = b[0] as u64 & 0x7f; while b[0] & 0x80 != 0 { r.read_exact(&mut b)?; i += 1; value += 1; value = (value << 7) + (b[0] as u64 & 0x7f) } Ok((value, i))} /// Parses the header of a pack-entry, yielding object type id, decompressed object size, and consumed bytesfn parse_header_info(data: &[u8]) -> (u8, u64, usize) { let mut c = data[0]; let mut i = 1; let type_id = (c >> 4) & 0b0000_0111; let mut size = c as u64 & 0b0000_1111; let mut s = 4; while c & 0b1000_0000 != 0 { c = data[i]; i += 1; size += ((c & 0b0111_1111) as u64) << s; s += 7 } (type_id, size, i)} fn streaming_parse_header_info(mut read: impl io::Read) -> Result<(u8, u64, usize), io::Error> { let mut byte = [0u8; 1]; read.read_exact(&mut byte)?; let mut c = byte[0]; let mut i = 1; let type_id = (c >> 4) & 0b0000_0111; let mut size = c as u64 & 0b0000_1111; let mut s = 4; while c & 0b1000_0000 != 0 { read.read_exact(&mut byte)?; c = byte[0]; i += 1; size += ((c & 0b0111_1111) as u64) << s; s += 7 } Ok((type_id, size, i))} impl Header { pub fn from_bytes(d: &[u8], pack_offset: u64) -> (Header, u64, u64) { let (type_id, size, mut consumed) = parse_header_info(d); use self::Header::*; let object = match type_id { OFS_DELTA => { let (offset, leb_bytes) = leb64decode(&d[consumed..]); let delta = OfsDelta { pack_offset: pack_offset - offset, }; consumed += leb_bytes; delta } REF_DELTA => { let delta = RefDelta { oid: owned::Id::from_20_bytes(&d[consumed..consumed + SHA1_SIZE]), }; consumed += SHA1_SIZE; delta } BLOB => Blob, TREE => Tree, COMMIT => Commit, TAG => Tag, _ => panic!("We currently don't support any V3 features or extensions"), }; (object, size, consumed as u64) } pub fn from_read(mut r: impl io::Read, pack_offset: u64) -> Result<(Header, u64, usize), io::Error> { let (type_id, size, mut consumed) = streaming_parse_header_info(&mut r)?; use self::Header::*; let object = match type_id { OFS_DELTA => { let (offset, leb_bytes) = streaming_leb64decode(&mut r)?; let delta = OfsDelta { pack_offset: pack_offset.checked_sub(offset).ok_or_else(|| { io::Error::new( io::ErrorKind::Other, format!( "Computing the absolute pack offset would underflow: {} - {}", pack_offset, offset ), ) })?, }; consumed += leb_bytes; delta } REF_DELTA => { let mut buf = [0u8; SHA1_SIZE]; r.read_exact(&mut buf)?; let delta = RefDelta { oid: owned::Id::new_sha1(buf), }; consumed += SHA1_SIZE; delta } BLOB => Blob, TREE => Tree, COMMIT => Commit, TAG => Tag, _ => panic!("We currently don't support any V3 features or extensions"), }; Ok((object, size, consumed)) }}
use git_object::{owned, SHA1_SIZE};
use std::io;
const _TYPE_EXT1: u8 = 0;
const COMMIT: u8 = 1;
const TREE: u8 = 2;
const BLOB: u8 = 3;
const TAG: u8 = 4;
const _TYPE_EXT2: u8 = 5;
const OFS_DELTA: u8 = 6;
const REF_DELTA: u8 = 7;
#[derive(PartialEq, Eq, Debug, Hash, Ord, PartialOrd, Clone)]
#[cfg_attr(feature = "serde1", derive(serde::Serialize, serde::Deserialize))]
pub struct Entry {
pub header: Header,
/// The decompressed size of the object in bytes
pub decompressed_size: u64,
/// absolute offset to compressed object data in the pack, just behind the header
pub data_offset: u64,
}
#[derive(PartialEq, Eq, Debug, Hash, Ord, PartialOrd, Clone, Copy)]
#[cfg_attr(feature = "serde1", derive(serde::Serialize, serde::Deserialize))]
pub enum Header {
Commit,
Tree,
Blob,
Tag,
/// An object within this pack if the LSB encoded offset would be larger than 20 bytes
/// Alternatively an object stored in the repository, if this is a thin pack
RefDelta {
oid: owned::Id,
},
/// The offset into the pack at which to find the base object header
OfsDelta {
pack_offset: u64,
},
}
impl Header {
pub fn to_kind(&self) -> Option<git_object::Kind> {
use git_object::Kind::*;
Some(match self {
Header::Tree => Tree,
Header::Blob => Blob,
Header::Commit => Commit,
Header::Tag => Tag,
Header::RefDelta { .. } | Header::OfsDelta { .. } => return None,
})
}
pub fn is_delta(&self) -> bool {
match self {
Header::OfsDelta { .. } | Header::RefDelta { .. } => true,
_ => false,
}
}
}
#[inline]
fn leb64decode(d: &[u8]) -> (u64, usize) {
let mut i = 0;
let mut c = d[i];
i += 1;
let mut value = c as u64 & 0x7f;
while c & 0x80 != 0 {
c = d[i];
i += 1;
value += 1;
value = (value << 7) + (c as u64 & 0x7f)
}
(value, i)
}
#[inline]
fn streaming_leb64decode(mut r: impl io::Read) -> Result<(u64, usize), io::Error> {
let mut b = [0u8; 1];
let mut i = 0;
r.read_exact(&mut b)?;
i += 1;
let mut value = b[0] as u64 & 0x7f;
while b[0] & 0x80 != 0 {
r.read_exact(&mut b)?;
i += 1;
value += 1;
value = (value << 7) + (b[0] as u64 & 0x7f)
}
Ok((value, i))
}
/// Parses the header of a pack-entry, yielding object type id, decompressed object size, and consumed bytes
fn parse_header_info(data: &[u8]) -> (u8, u64, usize) {
let mut c = data[0];
let mut i = 1;
let type_id = (c >> 4) & 0b0000_0111;
let mut size = c as u64 & 0b0000_1111;
let mut s = 4;
while c & 0b1000_0000 != 0 {
c = data[i];
i += 1;
size += ((c & 0b0111_1111) as u64) << s;
s += 7
}
(type_id, size, i)
}
fn streaming_parse_header_info(mut read: impl io::Read) -> Result<(u8, u64, usize), io::Error> {
let mut byte = [0u8; 1];
read.read_exact(&mut byte)?;
let mut c = byte[0];
let mut i = 1;
let type_id = (c >> 4) & 0b0000_0111;
let mut size = c as u64 & 0b0000_1111;
let mut s = 4;
while c & 0b1000_0000 != 0 {
read.read_exact(&mut byte)?;
c = byte[0];
i += 1;
size += ((c & 0b0111_1111) as u64) << s;
s += 7
}
Ok((type_id, size, i))
}
impl Header {
pub fn from_bytes(d: &[u8], pack_offset: u64) -> (Header, u64, u64) {
let (type_id, size, mut consumed) = parse_header_info(d);
use self::Header::*;
let object = match type_id {
OFS_DELTA => {
let (offset, leb_bytes) = leb64decode(&d[consumed..]);
let delta = OfsDelta {
pack_offset: pack_offset - offset,
};
consumed += leb_bytes;
delta
}
REF_DELTA => {
let delta = RefDelta {
oid: owned::Id::from_20_bytes(&d[consumed..consumed + SHA1_SIZE]),
};
consumed += SHA1_SIZE;
delta
}
BLOB => Blob,
TREE => Tree,
COMMIT => Commit,
TAG => Tag,
_ => panic!("We currently don't support any V3 features or extensions"),
};
(object, size, consumed as u64)
}
pub fn from_read(mut r: impl io::Read, pack_offset: u64) -> Result<(Header, u64, usize), io::Error> {
let (type_id, size, mut consumed) = streaming_parse_header_info(&mut r)?;
use self::Header::*;
let object = match type_id {
OFS_DELTA => {
let (offset, leb_bytes) = streaming_leb64decode(&mut r)?;
let delta = OfsDelta {
pack_offset: pack_offset.checked_sub(offset).ok_or_else(|| {
io::Error::new(
io::ErrorKind::Other,
format!(
"Computing the absolute pack offset would underflow: {} - {}",
pack_offset, offset
),
)
})?,
};
consumed += leb_bytes;
delta
}
REF_DELTA => {
let mut buf = [0u8; SHA1_SIZE];
r.read_exact(&mut buf)?;
let delta = RefDelta {
oid: owned::Id::new_sha1(buf),
};
consumed += SHA1_SIZE;
delta
}
BLOB => Blob,
TREE => Tree,
COMMIT => Commit,
TAG => Tag,
_ => panic!("We currently don't support any V3 features or extensions"),
};
Ok((object, size, consumed))
}
}