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use crate::store::loose::{sha1_path, Store, HEADER_READ_UNCOMPRESSED_BYTES};
use git_features::zlib;
use git_pack::{data, loose::object::header};
use std::{convert::TryInto, fs, io::Read, path::PathBuf};
#[derive(thiserror::Error, Debug)]
#[allow(missing_docs)]
pub enum Error {
#[error("decompression of loose object at '{path}' failed")]
DecompressFile {
source: zlib::inflate::Error,
path: PathBuf,
},
#[error(transparent)]
Decode(#[from] header::Error),
#[error("Could not {action} data at '{path}'")]
Io {
source: std::io::Error,
action: &'static str,
path: PathBuf,
},
}
impl Store {
const OPEN_ACTION: &'static str = "open";
pub fn contains(&self, id: impl AsRef<git_hash::oid>) -> bool {
sha1_path(id.as_ref(), self.path.clone()).is_file()
}
pub fn find<'a>(
&self,
id: impl AsRef<git_hash::oid>,
out: &'a mut Vec<u8>,
) -> Result<Option<data::Object<'a>>, Error> {
match self.find_inner(id.as_ref(), out) {
Ok(obj) => Ok(Some(obj)),
Err(err) => match err {
Error::Io {
source: err,
action,
path,
} => {
if action == Self::OPEN_ACTION && err.kind() == std::io::ErrorKind::NotFound {
Ok(None)
} else {
Err(Error::Io {
source: err,
action,
path,
})
}
}
err => Err(err),
},
}
}
fn find_inner<'a>(&self, id: &git_hash::oid, buf: &'a mut Vec<u8>) -> Result<data::Object<'a>, Error> {
let path = sha1_path(id, self.path.clone());
let mut inflate = zlib::Inflate::default();
let ((status, consumed_in, consumed_out), bytes_read) = {
let mut istream = fs::File::open(&path).map_err(|e| Error::Io {
source: e,
action: Self::OPEN_ACTION,
path: path.to_owned(),
})?;
buf.clear();
let bytes_read = istream.read_to_end(buf).map_err(|e| Error::Io {
source: e,
action: "read",
path: path.to_owned(),
})?;
buf.resize(bytes_read + HEADER_READ_UNCOMPRESSED_BYTES, 0);
let (input, output) = buf.split_at_mut(bytes_read);
(
inflate
.once(&input[..bytes_read], output)
.map_err(|e| Error::DecompressFile {
source: e,
path: path.to_owned(),
})?,
bytes_read,
)
};
assert_ne!(
status,
zlib::Status::BufError,
"Buffer errors might mean we encountered huge headers"
);
let decompressed_start = bytes_read;
let (kind, size, header_size) = header::decode(&buf[decompressed_start..decompressed_start + consumed_out])?;
let size: usize = size.try_into().expect("object size fits into machine architecture");
if status == zlib::Status::StreamEnd {
let decompressed_body_bytes_sans_header =
decompressed_start + header_size..decompressed_start + consumed_out;
assert_eq!(
consumed_out,
size + header_size,
"At this point we have decompressed everything and given 'size' should match"
);
buf.copy_within(decompressed_body_bytes_sans_header, 0);
} else {
buf.resize(bytes_read + size + header_size, 0);
{
let (input, output) = buf.split_at_mut(bytes_read);
let num_decompressed_bytes = zlib::stream::inflate::read(
&mut &input[consumed_in..],
&mut inflate.state,
&mut output[consumed_out..],
)
.map_err(|e| Error::Io {
source: e,
action: "deflate",
path: path.to_owned(),
})?;
assert_eq!(
num_decompressed_bytes + consumed_out,
size + header_size,
"Object should have been decompressed entirely and match given 'size'"
);
};
buf.copy_within(decompressed_start + header_size.., 0);
}
buf.resize(size, 0);
Ok(git_pack::data::Object {
kind,
data: buf,
pack_location: None,
})
}
}