ref: d1dc287210afd73705c21675dcbaa4eaf997fdde
dir: /sys/src/cmd/hgfs/revlog.c/
#include <u.h>
#include <libc.h>
#include <thread.h>
#include "dat.h"
#include "fns.h"
int
fmktemp(void)
{
static ulong id = 1;
char path[MAXPATH];
snprint(path, sizeof(path), "/tmp/hg%.12d%.8lux", getpid(), id++);
return create(path, OEXCL|ORDWR|ORCLOSE, 0600);
}
void
revlogupdate(Revlog *r)
{
uchar buf[64];
Revmap *m;
vlong noff;
int rev;
if(seek(r->ifd, r->ioff, 0) < 0)
return;
for(rev=r->nmap;;rev++){
if(readn(r->ifd, buf, sizeof(buf)) != sizeof(buf))
break;
if((rev % 16) == 0)
r->map = realloc(r->map, sizeof(r->map[0])*(rev+16));
m = &r->map[rev];
memset(m, 0, sizeof(*m));
m->hoff = (vlong)buf[0]<<40 |
(vlong)buf[1]<<32 |
(vlong)buf[2]<<24 |
(vlong)buf[3]<<16 |
(vlong)buf[4]<<8 |
(vlong)buf[5];
if(rev == 0)
m->hoff &= 0xFFFF;
m->rev = rev;
m->flags = buf[6]<<8 | buf[7];
m->hlen = buf[8]<<24 | buf[9]<<16 | buf[10]<<8 | buf[11];
m->flen = buf[12]<<24 | buf[13]<<16 | buf[14]<<8 | buf[15];
m->baserev = buf[16]<<24 | buf[17]<<16 | buf[18]<<8 | buf[19];
m->linkrev = buf[20]<<24 | buf[21]<<16 | buf[22]<<8 | buf[23];
m->p1rev = buf[24]<<24 | buf[25]<<16 | buf[26]<<8 | buf[27];
m->p2rev = buf[28]<<24 | buf[29]<<16 | buf[30]<<8 | buf[31];
memmove(m->hash, buf+32, HASHSZ);
noff = r->ioff + sizeof(buf);
if(r->dfd < 0){
m->hoff = noff;
noff = seek(r->ifd, m->hoff + m->hlen, 0);
if(noff < 0)
break;
}
r->ioff = noff;
}
r->nmap = rev;
}
int
revlogopen(Revlog *r, char *path, int mode)
{
r->ifd = -1;
r->dfd = -1;
r->tfd = -1;
r->tid = -1;
path = smprint("%s.i", path);
if((r->ifd = open(path, mode)) < 0){
free(path);
return -1;
}
path[strlen(path)-1] = 'd';
r->dfd = open(path, mode);
path[strlen(path)-2] = 0;
r->path = path;
r->ioff = 0;
r->nmap = 0;
r->map = nil;
revlogupdate(r);
return 0;
}
void
revlogclose(Revlog *r)
{
if(r->ifd >= 0){
close(r->ifd);
r->ifd = -1;
}
if(r->dfd >= 0){
close(r->dfd);
r->dfd = -1;
}
if(r->tfd >= 0){
close(r->tfd);
r->tfd = -1;
}
r->tid = -1;
free(r->map);
r->map = nil;
r->nmap = 0;
free(r->path);
r->path = nil;
}
uchar*
revhash(Revlog *r, int rev)
{
if(rev < 0 || rev >= r->nmap)
return nullid;
return r->map[rev].hash;
}
int
hashrev(Revlog *r, uchar hash[])
{
int rev;
for(rev=0; rev<r->nmap; rev++)
if(memcmp(r->map[rev].hash, hash, HASHSZ) == 0)
return rev;
return -1;
}
static int
prevlogrev(Revlog *r, int rev)
{
if(r->map[rev].baserev == rev)
return -1;
return rev-1;
}
static int
prevbundlerev(Revlog *r, int rev)
{
if(r->map[rev].baserev == rev)
return -1;
return r->map[rev].p1rev;
}
static Revmap**
getchain1(Revlog *r, int rev, int *count, int (*next)(Revlog *, int))
{
Revmap **chain;
if(rev < 0 || rev >= r->nmap){
if(*count <= 0)
return nil;
chain = malloc(sizeof(chain[0]) * ((*count)+1));
chain[*count] = nil;
*count = 0;
}else{
(*count)++;
if(chain = getchain1(r, (*next)(r, rev), count, next))
chain[(*count)++] = &r->map[rev];
}
return chain;
}
static Revmap**
getchain(Revlog *r, int rev, int (*next)(Revlog *, int))
{
int count = 0;
return getchain1(r, rev, &count, next);
}
int
revlogextract(Revlog *r, int rev, int ofd)
{
int err, hfd, pfd, bfd;
uchar hash[HASHSZ];
Revmap **chain, *m;
char buf[32];
vlong off;
int i;
err = -1;
bfd = -1;
pfd = -1;
if((chain = getchain(r, rev, prevlogrev)) == nil){
werrstr("bad patch chain");
goto errout;
}
off = seek(ofd, 0, 1);
if(off < 0){
werrstr("seek outfile: %r");
goto errout;
}
hfd = r->dfd < 0 ? r->ifd : r->dfd;
for(i=0; m = chain[i]; i++){
if(seek(hfd, m->hoff, 0) < 0){
werrstr("seek index: %r");
goto errout;
}
if(m == chain[0] && m->baserev == m->rev){
if(chain[1]){
if(bfd >= 0 && bfd != ofd)
close(bfd);
if((bfd = fmktemp()) < 0){
werrstr("create basefile: %r");
goto errout;
}
} else
bfd = ofd;
if(funzip(bfd, hfd, m->hlen) < 0){
werrstr("unzip basefile: %r");
goto errout;
}
} else {
if(pfd < 0){
if((pfd = fmktemp()) < 0){
werrstr("create patchfile: %r");
goto errout;
}
}
/* put a mark before the patch data */
snprint(buf, sizeof(buf), "%H", m->hash);
if(fpatchmark(pfd, buf) < 0){
werrstr("patchmark: %r");
goto errout;
}
if(funzip(pfd, hfd, m->hlen) < 0){
werrstr("unzip patchfile: %r");
goto errout;
}
}
}
m = chain[i-1];
if(pfd >= 0 && bfd >= 0 && bfd != ofd){
if(seek(pfd, 0, 0) < 0){
werrstr("seek patchfile: %r");
goto errout;
}
if(fpatch(ofd, bfd, pfd) < 0){
werrstr("patch: %r");
goto errout;
}
}
if(seek(ofd, off, 0) < 0){
werrstr("seek outfile: %r");
goto errout;
}
if(fhash(ofd, revhash(r, m->p1rev), revhash(r, m->p2rev), hash) < 0){
werrstr("hash outfile: %r");
goto errout;
}
if(memcmp(m->hash, hash, HASHSZ)){
werrstr("got bad hash");
goto errout;
}
err = 0;
errout:
if(pfd >= 0)
close(pfd);
if(bfd >= 0 && bfd != ofd)
close(bfd);
free(chain);
return err;
}
int
revlogopentemp(Revlog *r, int rev)
{
int fd;
if(r->tfd < 0 || rev != r->tid){
if((fd = fmktemp()) < 0)
return -1;
if(revlogextract(r, rev, fd) < 0){
close(fd);
return -1;
}
if(r->tfd >= 0)
close(r->tfd);
r->tfd = fd;
r->tid = rev;
}
fd = dup(r->tfd, -1);
if(seek(fd, 0, 0) < 0){
close(fd);
return -1;
}
return fd;
}
int
fmetaheader(int fd)
{
static char magic[2] = { 0x01, 0x0A, };
char buf[4096], *s, *p;
int o, n;
o = 0;
while(o < sizeof(buf)){
if((n = pread(fd, buf+o, sizeof(buf)-o, o)) <= 0)
break;
o += n;
if(o < sizeof(magic))
continue;
if(memcmp(buf, magic, sizeof(magic)) != 0)
break;
s = buf + sizeof(magic);
while((s - buf) <= (o - sizeof(magic))){
if((p = memchr(s, magic[0], o - (s - buf))) == nil)
break;
if(memcmp(p, magic, sizeof(magic)) == 0)
return (p - buf) + sizeof(magic);
s = p+1;
}
}
return 0;
}