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Junio C Hamano
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[PATCH] Add 'git show-branch'.
The 'git show-branches' command turns out to be reasonably useful, but painfully slow. So rewrite it in C, using ideas from merge-base while enhancing it a bit more. - Unlike show-branches, it can take --heads (show me all my heads), --tags (show me all my tags), or --all (both). - It can take --more=<number> to show beyond the merge-base. - It shows the short name for each commit in the extended SHA1 syntax. - It can find merge-base for more than two heads. Examples: $ git show-branch --more=6 HEAD is almost the same as "git log --pretty=oneline --max-count=6". $ git show-branch --merge-base master mhf misc finds the merge base of the three given heads. $ git show-branch master mhf misc shows logs from the top of these three branch heads, up to their common ancestor commit is shown. $ git show-branch --all --more=10 is poor-man's gitk, showing all the tags and heads, and going back 10 commits beyond the merge base of those refs. Signed-off-by: Junio C Hamano <junkio@cox.net>
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4 files changed

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lines changed

‎Makefile‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -84,7 +84,7 @@ PROG= git-update-cache git-diff-files git-init-db git-write-tree \
8484
git-diff-stages git-rev-parse git-patch-id git-pack-objects \
8585
git-unpack-objects git-verify-pack git-receive-pack git-send-pack \
8686
git-prune-packed git-fetch-pack git-upload-pack git-clone-pack \
87-
git-show-index git-daemon git-var git-peek-remote \
87+
git-show-index git-daemon git-var git-peek-remote git-show-branch \
8888
git-update-server-info git-show-rev-cache git-build-rev-cache
8989

9090
ifndef NO_CURL

‎commit.c‎

Lines changed: 15 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -38,23 +38,32 @@ enum cmit_fmt get_commit_format(const char *arg)
3838
die("invalid --pretty format");
3939
}
4040

41-
static struct commit *check_commit(struct object *obj, const unsigned char *sha1)
41+
static struct commit *check_commit(struct object *obj,
42+
const unsigned char *sha1,
43+
int quiet)
4244
{
4345
if (obj->type != commit_type) {
44-
error("Object %s is a %s, not a commit",
45-
sha1_to_hex(sha1), obj->type);
46+
if (!quiet)
47+
error("Object %s is a %s, not a commit",
48+
sha1_to_hex(sha1), obj->type);
4649
return NULL;
4750
}
4851
return (struct commit *) obj;
4952
}
5053

51-
struct commit *lookup_commit_reference(const unsigned char *sha1)
54+
struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
55+
int quiet)
5256
{
5357
struct object *obj = deref_tag(parse_object(sha1));
5458

5559
if (!obj)
5660
return NULL;
57-
return check_commit(obj, sha1);
61+
return check_commit(obj, sha1, quiet);
62+
}
63+
64+
struct commit *lookup_commit_reference(const unsigned char *sha1)
65+
{
66+
return lookup_commit_reference_gently(sha1, 0);
5867
}
5968

6069
struct commit *lookup_commit(const unsigned char *sha1)
@@ -69,7 +78,7 @@ struct commit *lookup_commit(const unsigned char *sha1)
6978
}
7079
if (!obj->type)
7180
obj->type = commit_type;
72-
return check_commit(obj, sha1);
81+
return check_commit(obj, sha1, 0);
7382
}
7483

7584
static unsigned long parse_commit_date(const char *buf)

‎commit.h‎

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -21,6 +21,8 @@ extern const char *commit_type;
2121

2222
struct commit *lookup_commit(const unsigned char *sha1);
2323
struct commit *lookup_commit_reference(const unsigned char *sha1);
24+
struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
25+
int quiet);
2426

2527
int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size);
2628

‎show-branch.c‎

Lines changed: 325 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,325 @@
1+
#include <stdlib.h>
2+
#include "cache.h"
3+
#include "commit.h"
4+
#include "refs.h"
5+
6+
static const char show_branch_usage[] =
7+
"git-show-branch [--all] [--heads] [--tags] [--more=count] [<refs>...]";
8+
9+
#define UNINTERESTING 01
10+
11+
#define REV_SHIFT 2
12+
#define MAX_REVS 29 /* should not exceed bits_per_int - REV_SHIFT */
13+
14+
static struct commit *interesting(struct commit_list *list)
15+
{
16+
while (list) {
17+
struct commit *commit = list->item;
18+
list = list->next;
19+
if (commit->object.flags & UNINTERESTING)
20+
continue;
21+
return commit;
22+
}
23+
return NULL;
24+
}
25+
26+
static struct commit *pop_one_commit(struct commit_list **list_p)
27+
{
28+
struct commit *commit;
29+
struct commit_list *list;
30+
list = *list_p;
31+
commit = list->item;
32+
*list_p = list->next;
33+
free(list);
34+
return commit;
35+
}
36+
37+
struct commit_name {
38+
int head_rev; /* which head's ancestor? */
39+
int generation; /* how many parents away from head_rev */
40+
};
41+
42+
/* Name the commit as nth generation ancestor of head_rev;
43+
* we count only the first-parent relationship for naming purposes.
44+
*/
45+
static void name_commit(struct commit *commit, int head_rev, int nth)
46+
{
47+
struct commit_name *name;
48+
if (!commit->object.util)
49+
commit->object.util = xmalloc(sizeof(struct commit_name));
50+
name = commit->object.util;
51+
name->head_rev = head_rev;
52+
name->generation = nth;
53+
}
54+
55+
/* Parent is the first parent of the commit. We may name it
56+
* as (n+1)th generation ancestor of the same head_rev as
57+
* commit is nth generation ancestore of, if that generation
58+
* number is better than the name it already has.
59+
*/
60+
static void name_parent(struct commit *commit, struct commit *parent)
61+
{
62+
struct commit_name *commit_name = commit->object.util;
63+
struct commit_name *parent_name = parent->object.util;
64+
if (!commit_name)
65+
return;
66+
if (!parent_name ||
67+
commit_name->generation + 1 < parent_name->generation)
68+
name_commit(parent, commit_name->head_rev,
69+
commit_name->generation + 1);
70+
}
71+
72+
static int mark_seen(struct commit *commit, struct commit_list **seen_p)
73+
{
74+
if (!commit->object.flags) {
75+
insert_by_date(commit, seen_p);
76+
return 1;
77+
}
78+
return 0;
79+
}
80+
81+
static void join_revs(struct commit_list **list_p,
82+
struct commit_list **seen_p,
83+
int num_rev, int extra)
84+
{
85+
int all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
86+
int all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
87+
88+
while (*list_p) {
89+
struct commit_list *parents;
90+
struct commit *commit = pop_one_commit(list_p);
91+
int flags = commit->object.flags & all_mask;
92+
int nth_parent = 0;
93+
int still_interesting = !!interesting(*list_p);
94+
95+
if (!still_interesting && extra < 0)
96+
break;
97+
98+
mark_seen(commit, seen_p);
99+
if ((flags & all_revs) == all_revs)
100+
flags |= UNINTERESTING;
101+
parents = commit->parents;
102+
103+
while (parents) {
104+
struct commit *p = parents->item;
105+
int this_flag = p->object.flags;
106+
parents = parents->next;
107+
nth_parent++;
108+
if (nth_parent == 1)
109+
name_parent(commit, p);
110+
111+
if ((this_flag & flags) == flags)
112+
continue;
113+
parse_commit(p);
114+
if (mark_seen(p, seen_p) && !still_interesting)
115+
extra--;
116+
p->object.flags |= flags;
117+
insert_by_date(p, list_p);
118+
}
119+
}
120+
}
121+
122+
static void show_one_commit(struct commit *commit, char **head_name)
123+
{
124+
char pretty[128], *cp;
125+
struct commit_name *name = commit->object.util;
126+
pretty_print_commit(CMIT_FMT_ONELINE, commit->buffer, ~0,
127+
pretty, sizeof(pretty));
128+
if (!strncmp(pretty, "[PATCH] ", 8))
129+
cp = pretty + 8;
130+
else
131+
cp = pretty;
132+
if (name && head_name) {
133+
printf("[%s", head_name[name->head_rev]);
134+
if (name->generation)
135+
printf("~%d", name->generation);
136+
printf("] ");
137+
}
138+
puts(cp);
139+
}
140+
141+
static char *ref_name[MAX_REVS + 1];
142+
static int ref_name_cnt;
143+
144+
static int append_ref(const char *refname, const unsigned char *sha1)
145+
{
146+
struct commit *commit = lookup_commit_reference_gently(sha1, 1);
147+
if (!commit)
148+
return 0;
149+
if (MAX_REVS < ref_name_cnt) {
150+
fprintf(stderr, "warning: ignoring %s; "
151+
"cannot handle more than %d refs",
152+
refname, MAX_REVS);
153+
return 0;
154+
}
155+
ref_name[ref_name_cnt++] = strdup(refname);
156+
ref_name[ref_name_cnt] = NULL;
157+
return 0;
158+
}
159+
160+
static int append_head_ref(const char *refname, const unsigned char *sha1)
161+
{
162+
if (strncmp(refname, "refs/heads/", 11))
163+
return 0;
164+
return append_ref(refname + 5, sha1);
165+
}
166+
167+
static int append_tag_ref(const char *refname, const unsigned char *sha1)
168+
{
169+
if (strncmp(refname, "refs/tags/", 10))
170+
return 0;
171+
return append_ref(refname + 5, sha1);
172+
}
173+
174+
static void snarf_refs(int head, int tag)
175+
{
176+
if (head)
177+
for_each_ref(append_head_ref);
178+
if (tag)
179+
for_each_ref(append_tag_ref);
180+
}
181+
182+
static int rev_is_head(char *head_path, int headlen,
183+
char *name,
184+
unsigned char *head_sha1, unsigned char *sha1)
185+
{
186+
int namelen;
187+
if ((!head_path[0]) || memcmp(head_sha1, sha1, 20))
188+
return 0;
189+
namelen = strlen(name);
190+
if ((headlen < namelen) ||
191+
memcmp(head_path + headlen - namelen, name, namelen))
192+
return 0;
193+
if (headlen == namelen ||
194+
head_path[headlen - namelen - 1] == '/')
195+
return 1;
196+
return 0;
197+
}
198+
199+
static int show_merge_base(struct commit_list *seen, int num_rev)
200+
{
201+
int all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
202+
int all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
203+
204+
while (seen) {
205+
struct commit *commit = pop_one_commit(&seen);
206+
int flags = commit->object.flags & all_mask;
207+
if (!(flags & UNINTERESTING) &&
208+
((flags & all_revs) == all_revs)) {
209+
puts(sha1_to_hex(commit->object.sha1));
210+
return 0;
211+
}
212+
}
213+
return 1;
214+
}
215+
216+
int main(int ac, char **av)
217+
{
218+
struct commit *rev[MAX_REVS], *commit;
219+
struct commit_list *list = NULL, *seen = NULL;
220+
int num_rev, i, extra = 0;
221+
int all_heads = 0, all_tags = 0;
222+
char head_path[128];
223+
int head_path_len;
224+
unsigned char head_sha1[20];
225+
int merge_base = 0;
226+
227+
while (1 < ac && av[1][0] == '-') {
228+
char *arg = av[1];
229+
if (!strcmp(arg, "--all"))
230+
all_heads = all_tags = 1;
231+
else if (!strcmp(arg, "--heads"))
232+
all_heads = 1;
233+
else if (!strcmp(arg, "--tags"))
234+
all_tags = 1;
235+
else if (!strcmp(arg, "--more"))
236+
extra = 1;
237+
else if (!strncmp(arg, "--more=", 7)) {
238+
extra = atoi(arg + 7);
239+
if (extra < 0)
240+
usage(show_branch_usage);
241+
}
242+
else if (!strcmp(arg, "--merge-base"))
243+
merge_base = 1;
244+
else
245+
usage(show_branch_usage);
246+
ac--; av++;
247+
}
248+
ac--; av++;
249+
250+
if (all_heads + all_tags)
251+
snarf_refs(all_heads, all_tags);
252+
253+
while (0 < ac) {
254+
unsigned char revkey[20];
255+
if (get_sha1(*av, revkey))
256+
die("bad sha1 reference %s", *av);
257+
append_ref(*av, revkey);
258+
ac--; av++;
259+
}
260+
261+
/* If still no revs, then add heads */
262+
if (!ref_name_cnt)
263+
snarf_refs(1, 0);
264+
265+
for (num_rev = 0; ref_name[num_rev]; num_rev++) {
266+
unsigned char revkey[20];
267+
268+
if (MAX_REVS <= num_rev)
269+
die("cannot handle more than %d revs.", MAX_REVS);
270+
if (get_sha1(ref_name[num_rev], revkey))
271+
usage(show_branch_usage);
272+
commit = lookup_commit_reference(revkey);
273+
if (!commit)
274+
die("cannot find commit %s (%s)",
275+
ref_name[num_rev], revkey);
276+
parse_commit(commit);
277+
if (!commit->object.util)
278+
name_commit(commit, num_rev, 0);
279+
mark_seen(commit, &seen);
280+
281+
/* rev#0 uses bit REV_SHIFT, rev#1 uses bit REV_SHIFT+1,
282+
* and so on. REV_SHIFT bits from bit 0 are used for
283+
* internal bookkeeping.
284+
*/
285+
commit->object.flags |= 1u << (num_rev + REV_SHIFT);
286+
insert_by_date(commit, &list);
287+
rev[num_rev] = commit;
288+
}
289+
join_revs(&list, &seen, num_rev, extra);
290+
291+
head_path_len = readlink(".git/HEAD", head_path, sizeof(head_path)-1);
292+
if ((head_path_len < 0) || get_sha1("HEAD", head_sha1))
293+
head_path[0] = 0;
294+
else
295+
head_path[head_path_len] = 0;
296+
297+
if (merge_base)
298+
return show_merge_base(seen, num_rev);
299+
300+
if (1 < num_rev)
301+
for (i = 0; i < num_rev; i++) {
302+
int j;
303+
int is_head = rev_is_head(head_path,
304+
head_path_len,
305+
ref_name[i],
306+
head_sha1,
307+
rev[i]->object.sha1);
308+
for (j = 0; j < i; j++)
309+
putchar(' ');
310+
printf("%c [%s] ", is_head ? '*' : '!', ref_name[i]);
311+
show_one_commit(rev[i], NULL);
312+
}
313+
while (seen) {
314+
struct commit *commit = pop_one_commit(&seen);
315+
int this_flag = commit->object.flags;
316+
if ((this_flag & UNINTERESTING) && (--extra < 0))
317+
break;
318+
for (i = 0; i < num_rev; i++)
319+
putchar((this_flag & (1u << (i + REV_SHIFT)))
320+
? '+' : ' ');
321+
putchar(' ');
322+
show_one_commit(commit, ref_name);
323+
}
324+
return 0;
325+
}

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