git/csum-file.c
Joachim B Haga 12f6c308d5 Make zlib compression level configurable, and change default.
With the change in default, "git add ." on kernel dir is about
twice as fast as before, with only minimal (0.5%) change in
object size. The speed difference is even more noticeable
when committing large files, which is now up to 8 times faster.

The configurability is through setting core.compression = [-1..9]
which maps to the zlib constants; -1 is the default, 0 is no
compression, and 1..9 are various speed/size tradeoffs, 9
being slowest.

Signed-off-by: Joachim B Haga (cjhaga@fys.uio.no)
Acked-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-07-03 13:55:11 -07:00

147 lines
2.9 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 int 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 0;
}
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 update)
{
unsigned offset = f->offset;
if (offset) {
SHA1_Update(&f->ctx, f->buffer, offset);
sha1flush(f, offset);
}
SHA1_Final(f->buffer, &f->ctx);
if (result)
memcpy(result, f->buffer, 20);
if (update)
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)
{
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;
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;
SHA1_Init(&f->ctx);
return f;
}
int sha1write_compressed(struct sha1file *f, void *in, unsigned int size)
{
z_stream stream;
unsigned long maxsize;
void *out;
memset(&stream, 0, sizeof(stream));
deflateInit(&stream, zlib_compression_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;
}