git/csum-file.c
Dana L. How f02153696f Alter sha1close() 3rd argument to request flush only
update=0 suppressed writing the final SHA-1 but was not used.
Now final=0 suppresses SHA-1 finalization, SHA-1 writing,
and closing -- in other words,  only flush the buffer.

Signed-off-by: Dana L. How <danahow@gmail.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-05-20 21:55:26 -07:00

163 lines
3.2 KiB
C

/*
* csum-file.c
*
* Copyright (C) 2005 Linus Torvalds
*
* Simple file write infrastructure for writing SHA1-summed
* files. Useful when you write a file that you want to be
* able to verify hasn't been messed with afterwards.
*/
#include "cache.h"
#include "csum-file.h"
static void sha1flush(struct sha1file *f, unsigned int count)
{
void *buf = f->buffer;
for (;;) {
int ret = xwrite(f->fd, buf, count);
if (ret > 0) {
buf = (char *) buf + ret;
count -= ret;
if (count)
continue;
return;
}
if (!ret)
die("sha1 file '%s' write error. Out of diskspace", f->name);
die("sha1 file '%s' write error (%s)", f->name, strerror(errno));
}
}
int sha1close(struct sha1file *f, unsigned char *result, int final)
{
unsigned offset = f->offset;
if (offset) {
SHA1_Update(&f->ctx, f->buffer, offset);
sha1flush(f, offset);
f->offset = 0;
}
if (!final)
return 0; /* only want to flush (no checksum write, no close) */
SHA1_Final(f->buffer, &f->ctx);
if (result)
hashcpy(result, f->buffer);
sha1flush(f, 20);
if (close(f->fd))
die("%s: sha1 file error on close (%s)", f->name, strerror(errno));
free(f);
return 0;
}
int sha1write(struct sha1file *f, void *buf, unsigned int count)
{
if (f->do_crc)
f->crc32 = crc32(f->crc32, buf, count);
while (count) {
unsigned offset = f->offset;
unsigned left = sizeof(f->buffer) - offset;
unsigned nr = count > left ? left : count;
memcpy(f->buffer + offset, buf, nr);
count -= nr;
offset += nr;
buf = (char *) buf + nr;
left -= nr;
if (!left) {
SHA1_Update(&f->ctx, f->buffer, offset);
sha1flush(f, offset);
offset = 0;
}
f->offset = offset;
}
return 0;
}
struct sha1file *sha1create(const char *fmt, ...)
{
struct sha1file *f;
unsigned len;
va_list arg;
int fd;
f = xmalloc(sizeof(*f));
va_start(arg, fmt);
len = vsnprintf(f->name, sizeof(f->name), fmt, arg);
va_end(arg);
if (len >= PATH_MAX)
die("you wascally wabbit, you");
f->namelen = len;
fd = open(f->name, O_CREAT | O_EXCL | O_WRONLY, 0666);
if (fd < 0)
die("unable to open %s (%s)", f->name, strerror(errno));
f->fd = fd;
f->error = 0;
f->offset = 0;
f->do_crc = 0;
SHA1_Init(&f->ctx);
return f;
}
struct sha1file *sha1fd(int fd, const char *name)
{
struct sha1file *f;
unsigned len;
f = xmalloc(sizeof(*f));
len = strlen(name);
if (len >= PATH_MAX)
die("you wascally wabbit, you");
f->namelen = len;
memcpy(f->name, name, len+1);
f->fd = fd;
f->error = 0;
f->offset = 0;
f->do_crc = 0;
SHA1_Init(&f->ctx);
return f;
}
int sha1write_compressed(struct sha1file *f, void *in, unsigned int size, int level)
{
z_stream stream;
unsigned long maxsize;
void *out;
memset(&stream, 0, sizeof(stream));
deflateInit(&stream, level);
maxsize = deflateBound(&stream, size);
out = xmalloc(maxsize);
/* Compress it */
stream.next_in = in;
stream.avail_in = size;
stream.next_out = out;
stream.avail_out = maxsize;
while (deflate(&stream, Z_FINISH) == Z_OK)
/* nothing */;
deflateEnd(&stream);
size = stream.total_out;
sha1write(f, out, size);
free(out);
return size;
}
void crc32_begin(struct sha1file *f)
{
f->crc32 = crc32(0, Z_NULL, 0);
f->do_crc = 1;
}
uint32_t crc32_end(struct sha1file *f)
{
f->do_crc = 0;
return f->crc32;
}