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// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation: version 2 of the License, dated June 1991.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program; if not, see <https://www.gnu.org/licenses/>.
use crate::hash::{HashAlgorithm, GIT_MAX_RAWSZ};
use std::ffi::CStr;
use std::io::{self, Write};
use std::os::raw::c_void;
/// A writer that can write files identified by their hash or containing a trailing hash.
pub struct HashFile {
ptr: *mut c_void,
algo: HashAlgorithm,
}
impl HashFile {
/// Create a new HashFile.
///
/// The hash used will be `algo`, its name should be in `name`, and an open file descriptor
/// pointing to that file should be in `fd`.
pub fn new(algo: HashAlgorithm, fd: i32, name: &CStr) -> HashFile {
HashFile {
ptr: unsafe { c::hashfd(algo.hash_algo_ptr(), fd, name.as_ptr()) },
algo,
}
}
/// Finalize this HashFile instance.
///
/// Returns the hash computed over the data.
pub fn finalize(self, component: u32, flags: u32) -> Vec<u8> {
let mut result = vec![0u8; GIT_MAX_RAWSZ];
unsafe { c::finalize_hashfile(self.ptr, result.as_mut_ptr(), component, flags) };
result.truncate(self.algo.raw_len());
result
}
}
impl Write for HashFile {
fn write(&mut self, data: &[u8]) -> io::Result<usize> {
for chunk in data.chunks(u32::MAX as usize) {
unsafe {
c::hashwrite(
self.ptr,
chunk.as_ptr() as *const c_void,
chunk.len() as u32,
)
};
}
Ok(data.len())
}
fn flush(&mut self) -> io::Result<()> {
unsafe { c::hashflush(self.ptr) };
Ok(())
}
}
pub mod c {
use std::os::raw::{c_char, c_int, c_void};
extern "C" {
pub fn hashfd(algop: *const c_void, fd: i32, name: *const c_char) -> *mut c_void;
pub fn hashwrite(f: *mut c_void, data: *const c_void, len: u32);
pub fn hashflush(f: *mut c_void);
pub fn finalize_hashfile(
f: *mut c_void,
data: *mut u8,
component: u32,
flags: u32,
) -> c_int;
}
}
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