git: rename internal 'git/fetch' plumbing to 'git/get'

This caused some confusion, so to make it clear that
it's plumbing and has nothing to do with 'git fetch',
rename it.

1 files changed, 372 insertions, 0 deletions

diff --git a/sys/src/cmd/git/get.c b/sys/src/cmd/git/get.c
new file mode 100644
index 000000000..95dfe106e
--- /dev/null
+++ b/sys/src/cmd/git/get.c
@@ -0,0 +1,372 @@
+#include <u.h>
+#include <libc.h>
+
+#include "git.h"
+
+char *fetchbranch;
+char *upstream = "origin";
+int listonly;
+
+int
+resolveremote(Hash *h, char *ref)
+{
+	char buf[128], *s;
+	int r, f;
+
+	ref = strip(ref);
+	if((r = hparse(h, ref)) != -1)
+		return r;
+	/* Slightly special handling: translate remote refs to local ones. */
+	if(strcmp(ref, "HEAD") == 0){
+		snprint(buf, sizeof(buf), ".git/HEAD");
+	}else if(strstr(ref, "refs/heads") == ref){
+		ref += strlen("refs/heads");
+		snprint(buf, sizeof(buf), ".git/refs/remotes/%s/%s", upstream, ref);
+	}else if(strstr(ref, "refs/tags") == ref){
+		ref += strlen("refs/tags");
+		snprint(buf, sizeof(buf), ".git/refs/tags/%s/%s", upstream, ref);
+	}else{
+		return -1;
+	}
+
+	r = -1;
+	s = strip(buf);
+	if((f = open(s, OREAD)) == -1)
+		return -1;
+	if(readn(f, buf, sizeof(buf)) >= 40)
+		r = hparse(h, buf);
+	close(f);
+
+	if(r == -1 && strstr(buf, "ref:") == buf)
+		return resolveremote(h, buf + strlen("ref:"));
+	return r;
+}
+
+int
+rename(char *pack, char *idx, Hash h)
+{
+	char name[128];
+	Dir st;
+
+	nulldir(&st);
+	st.name = name;
+	snprint(name, sizeof(name), "%H.pack", h);
+	if(access(name, AEXIST) == 0)
+		fprint(2, "warning, pack %s already fetched\n", name);
+	else if(dirwstat(pack, &st) == -1)
+		return -1;
+	snprint(name, sizeof(name), "%H.idx", h);
+	if(access(name, AEXIST) == 0)
+		fprint(2, "warning, pack %s already indexed\n", name);
+	else if(dirwstat(idx, &st) == -1)
+		return -1;
+	return 0;
+}
+
+int
+checkhash(int fd, vlong sz, Hash *hcomp)
+{
+	DigestState *st;
+	Hash hexpect;
+	char buf[Pktmax];
+	vlong n, r;
+	int nr;
+	
+	if(sz < 28){
+		werrstr("undersize packfile");
+		return -1;
+	}
+
+	st = nil;
+	n = 0;
+	while(n != sz - 20){
+		nr = sizeof(buf);
+		if(sz - n - 20 < sizeof(buf))
+			nr = sz - n - 20;
+		r = readn(fd, buf, nr);
+		if(r != nr)
+			return -1;
+		st = sha1((uchar*)buf, nr, nil, st);
+		n += r;
+	}
+	sha1(nil, 0, hcomp->h, st);
+	if(readn(fd, hexpect.h, sizeof(hexpect.h)) != sizeof(hexpect.h))
+		sysfatal("truncated packfile");
+	if(!hasheq(hcomp, &hexpect)){
+		werrstr("bad hash: %H != %H", *hcomp, hexpect);
+		return -1;
+	}
+	return 0;
+}
+
+int
+mkoutpath(char *path)
+{
+	char s[128];
+	char *p;
+	int fd;
+
+	snprint(s, sizeof(s), "%s", path);
+	for(p=strchr(s+1, '/'); p; p=strchr(p+1, '/')){
+		*p = 0;
+		if(access(s, AEXIST) != 0){
+			fd = create(s, OREAD, DMDIR | 0775);
+			if(fd == -1)
+				return -1;
+			close(fd);
+		}		
+		*p = '/';
+	}
+	return 0;
+}
+
+int
+branchmatch(char *br, char *pat)
+{
+	char name[128];
+
+	if(strstr(pat, "refs/heads") == pat)
+		snprint(name, sizeof(name), "%s", pat);
+	else if(strstr(pat, "heads"))
+		snprint(name, sizeof(name), "refs/%s", pat);
+	else
+		snprint(name, sizeof(name), "refs/heads/%s", pat);
+	return strcmp(br, name) == 0;
+}
+
+char *
+matchcap(char *s, char *cap, int full)
+{
+	if(strncmp(s, cap, strlen(cap)) == 0)
+		if(!full || strlen(s) == strlen(cap))
+			return s + strlen(cap);
+	return nil;
+}
+
+void
+handlecaps(char *caps)
+{
+	char *p, *n, *c, *r;
+
+	for(p = caps; p != nil; p = n){
+		n = strchr(p, ' ');
+		if(n != nil)
+			*n++ = 0;
+		if((c = matchcap(p, "symref=", 0)) != nil){
+			if((r = strchr(c, ':')) != nil){
+				*r++ = '\0';
+				print("symref %s %s\n", c, r);
+			}
+		}
+	}
+}
+
+void
+fail(char *pack, char *idx, char *msg, ...)
+{
+	char buf[ERRMAX];
+	va_list ap;
+
+	va_start(ap, msg);
+	snprint(buf, sizeof(buf), msg, ap);
+	va_end(ap);
+
+	remove(pack);
+	remove(idx);
+	fprint(2, "%s", buf);
+	exits(buf);
+}
+
+int
+fetchpack(Conn *c)
+{
+	char buf[Pktmax], *sp[3], *ep;
+	char *packtmp, *idxtmp, **ref;
+	Hash h, *have, *want;
+	int nref, refsz, first;
+	int i, n, l, req, pfd;
+	vlong packsz;
+	Objset hadobj;
+	Object *o;
+
+	nref = 0;
+	refsz = 16;
+	first = 1;
+	have = eamalloc(refsz, sizeof(have[0]));
+	want = eamalloc(refsz, sizeof(want[0]));
+	ref = eamalloc(refsz, sizeof(ref[0]));
+	while(1){
+		n = readpkt(c, buf, sizeof(buf));
+		if(n == -1)
+			return -1;
+		if(n == 0)
+			break;
+		if(strncmp(buf, "ERR ", 4) == 0)
+			sysfatal("%s", buf + 4);
+
+		if(first && n > strlen(buf))
+			handlecaps(buf + strlen(buf) + 1);
+		first = 0;
+
+		getfields(buf, sp, nelem(sp), 1, " \t\n\r");
+		if(strstr(sp[1], "^{}"))
+			continue;
+		if(fetchbranch && !branchmatch(sp[1], fetchbranch))
+			continue;
+		if(refsz == nref + 1){
+			refsz *= 2;
+			have = earealloc(have, refsz, sizeof(have[0]));
+			want = earealloc(want, refsz, sizeof(want[0]));
+			ref = earealloc(ref, refsz, sizeof(ref[0]));
+		}
+		if(hparse(&want[nref], sp[0]) == -1)
+			sysfatal("invalid hash %s", sp[0]);
+		if (resolveremote(&have[nref], sp[1]) == -1)
+			memset(&have[nref], 0, sizeof(have[nref]));
+		ref[nref] = estrdup(sp[1]);
+		nref++;
+	}
+	if(listonly){
+		flushpkt(c);
+		goto showrefs;
+	}
+
+	if(writephase(c) == -1)
+		sysfatal("write: %r");
+	req = 0;
+	for(i = 0; i < nref; i++){
+		if(hasheq(&have[i], &want[i]))
+			continue;
+		if((o = readobject(want[i])) != nil){
+			unref(o);
+			continue;
+		}
+		n = snprint(buf, sizeof(buf), "want %H\n", want[i]);
+		if(writepkt(c, buf, n) == -1)
+			sysfatal("could not send want for %H", want[i]);
+		req = 1;
+	}
+	flushpkt(c);
+	osinit(&hadobj);
+	for(i = 0; i < nref; i++){
+		if(hasheq(&have[i], &Zhash) || oshas(&hadobj, have[i]))
+			continue;
+		if((o = readobject(have[i])) == nil)
+			sysfatal("missing object we should have: %H", have[i]);
+		osadd(&hadobj, o);
+		unref(o);	
+		n = snprint(buf, sizeof(buf), "have %H\n", have[i]);
+		if(writepkt(c, buf, n + 1) == -1)
+			sysfatal("could not send have for %H", have[i]);
+	}
+	osclear(&hadobj);
+	if(!req)
+		flushpkt(c);
+
+	n = snprint(buf, sizeof(buf), "done\n");
+	if(writepkt(c, buf, n) == -1)
+		sysfatal("write: %r");
+	if(!req)
+		goto showrefs;
+	if(readphase(c) == -1)
+		sysfatal("read: %r");
+	if((n = readpkt(c, buf, sizeof(buf))) == -1)
+		sysfatal("read: %r");
+	buf[n] = 0;
+
+	if((packtmp = smprint(".git/objects/pack/fetch.%d.pack", getpid())) == nil)
+		sysfatal("smprint: %r");
+	if((idxtmp = smprint(".git/objects/pack/fetch.%d.idx", getpid())) == nil)
+		sysfatal("smprint: %r");
+	if(mkoutpath(packtmp) == -1)
+		sysfatal("could not create %s: %r", packtmp);
+	if((pfd = create(packtmp, ORDWR, 0664)) == -1)
+		sysfatal("could not create %s: %r", packtmp);
+
+	fprint(2, "fetching...\n");
+	/*
+	 * Work around torvalds git bug: we get duplicate have lines
+	 * somtimes, even though the protocol is supposed to start the
+	 * pack file immediately.
+	 *
+	 * Skip ahead until we read 'PACK' off the wire
+	 */
+	while(1){
+		if(readn(c->rfd, buf, 4) != 4)
+			sysfatal("fetch packfile: short read");
+		buf[4] = 0;
+		if(strncmp(buf, "PACK", 4) == 0)
+			break;
+		l = strtol(buf, &ep, 16);
+		if(l == 0 || ep != buf + 4)
+			sysfatal("fetch packfile: junk pktline");
+		if(readn(c->rfd, buf, l) != l)
+			sysfatal("fetch packfile: short read");
+	}
+	if(write(pfd, "PACK", 4) != 4)
+		sysfatal("write pack header: %r");
+	packsz = 4;
+	while(1){
+		n = read(c->rfd, buf, sizeof buf);
+		if(n == 0)
+			break;
+		if(n == -1 || write(pfd, buf, n) != n)
+			sysfatal("fetch packfile: %r");
+		packsz += n;
+	}
+
+	closeconn(c);
+	if(seek(pfd, 0, 0) == -1)
+		fail(packtmp, idxtmp, "packfile seek: %r");
+	if(checkhash(pfd, packsz, &h) == -1)
+		fail(packtmp, idxtmp, "corrupt packfile: %r");
+	close(pfd);
+	if(indexpack(packtmp, idxtmp, h) == -1)
+		fail(packtmp, idxtmp, "could not index fetched pack: %r");
+	if(rename(packtmp, idxtmp, h) == -1)
+		fail(packtmp, idxtmp, "could not rename indexed pack: %r");
+
+showrefs:
+	for(i = 0; i < nref; i++){
+		print("remote %s %H local %H\n", ref[i], want[i], have[i]);
+		free(ref[i]);
+	}
+	free(ref);
+	free(want);
+	free(have);
+	return 0;
+}
+
+void
+usage(void)
+{
+	fprint(2, "usage: %s [-dl] [-b br] [-u upstream] remote\n", argv0);
+	fprint(2, "\t-b br:	only fetch matching branch 'br'\n");
+	fprint(2, "remote:	fetch from this repository\n");
+	exits("usage");
+}
+
+void
+main(int argc, char **argv)
+{
+	Conn c;
+
+	ARGBEGIN{
+	case 'b':	fetchbranch=EARGF(usage());	break;
+	case 'u':	upstream=EARGF(usage());	break;
+	case 'd':	chattygit++;			break;
+	case 'l':	listonly++;			break;
+	default:	usage();			break;
+	}ARGEND;
+
+	gitinit();
+	if(argc != 1)
+		usage();
+
+	if(gitconnect(&c, argv[0], "upload") == -1)
+		sysfatal("could not dial %s: %r", argv[0]);
+	if(fetchpack(&c) == -1)
+		sysfatal("fetch failed: %r");
+	closeconn(&c);
+	exits(nil);
+}