Why is it bad to rewind a branch that has already been pushed out?
[git] / builtin-rev-list.c
1 #include "cache.h"
2 #include "refs.h"
3 #include "tag.h"
4 #include "commit.h"
5 #include "tree.h"
6 #include "blob.h"
7 #include "tree-walk.h"
8 #include "diff.h"
9 #include "revision.h"
10 #include "list-objects.h"
11 #include "builtin.h"
12
13 /* bits #0-15 in revision.h */
14
15 #define COUNTED         (1u<<16)
16
17 static const char rev_list_usage[] =
18 "git-rev-list [OPTION] <commit-id>... [ -- paths... ]\n"
19 "  limiting output:\n"
20 "    --max-count=nr\n"
21 "    --max-age=epoch\n"
22 "    --min-age=epoch\n"
23 "    --sparse\n"
24 "    --no-merges\n"
25 "    --remove-empty\n"
26 "    --all\n"
27 "    --stdin\n"
28 "  ordering output:\n"
29 "    --topo-order\n"
30 "    --date-order\n"
31 "  formatting output:\n"
32 "    --parents\n"
33 "    --objects | --objects-edge\n"
34 "    --unpacked\n"
35 "    --header | --pretty\n"
36 "    --abbrev=nr | --no-abbrev\n"
37 "    --abbrev-commit\n"
38 "  special purpose:\n"
39 "    --bisect"
40 ;
41
42 static struct rev_info revs;
43
44 static int bisect_list;
45 static int show_timestamp;
46 static int hdr_termination;
47 static const char *header_prefix;
48
49 static void show_commit(struct commit *commit)
50 {
51         if (show_timestamp)
52                 printf("%lu ", commit->date);
53         if (header_prefix)
54                 fputs(header_prefix, stdout);
55         if (commit->object.flags & BOUNDARY)
56                 putchar('-');
57         else if (revs.left_right) {
58                 if (commit->object.flags & SYMMETRIC_LEFT)
59                         putchar('<');
60                 else
61                         putchar('>');
62         }
63         if (revs.abbrev_commit && revs.abbrev)
64                 fputs(find_unique_abbrev(commit->object.sha1, revs.abbrev),
65                       stdout);
66         else
67                 fputs(sha1_to_hex(commit->object.sha1), stdout);
68         if (revs.parents) {
69                 struct commit_list *parents = commit->parents;
70                 while (parents) {
71                         struct object *o = &(parents->item->object);
72                         parents = parents->next;
73                         if (o->flags & TMP_MARK)
74                                 continue;
75                         printf(" %s", sha1_to_hex(o->sha1));
76                         o->flags |= TMP_MARK;
77                 }
78                 /* TMP_MARK is a general purpose flag that can
79                  * be used locally, but the user should clean
80                  * things up after it is done with them.
81                  */
82                 for (parents = commit->parents;
83                      parents;
84                      parents = parents->next)
85                         parents->item->object.flags &= ~TMP_MARK;
86         }
87         if (revs.commit_format == CMIT_FMT_ONELINE)
88                 putchar(' ');
89         else
90                 putchar('\n');
91
92         if (revs.verbose_header) {
93                 static char pretty_header[16384];
94                 pretty_print_commit(revs.commit_format, commit, ~0,
95                                     pretty_header, sizeof(pretty_header),
96                                     revs.abbrev, NULL, NULL, revs.relative_date);
97                 printf("%s%c", pretty_header, hdr_termination);
98         }
99         fflush(stdout);
100         if (commit->parents) {
101                 free_commit_list(commit->parents);
102                 commit->parents = NULL;
103         }
104         free(commit->buffer);
105         commit->buffer = NULL;
106 }
107
108 static void show_object(struct object_array_entry *p)
109 {
110         /* An object with name "foo\n0000000..." can be used to
111          * confuse downstream git-pack-objects very badly.
112          */
113         const char *ep = strchr(p->name, '\n');
114         if (ep) {
115                 printf("%s %.*s\n", sha1_to_hex(p->item->sha1),
116                        (int) (ep - p->name),
117                        p->name);
118         }
119         else
120                 printf("%s %s\n", sha1_to_hex(p->item->sha1), p->name);
121 }
122
123 static void show_edge(struct commit *commit)
124 {
125         printf("-%s\n", sha1_to_hex(commit->object.sha1));
126 }
127
128 /*
129  * This is a truly stupid algorithm, but it's only
130  * used for bisection, and we just don't care enough.
131  *
132  * We care just barely enough to avoid recursing for
133  * non-merge entries.
134  */
135 static int count_distance(struct commit_list *entry)
136 {
137         int nr = 0;
138
139         while (entry) {
140                 struct commit *commit = entry->item;
141                 struct commit_list *p;
142
143                 if (commit->object.flags & (UNINTERESTING | COUNTED))
144                         break;
145                 if (!revs.prune_fn || (commit->object.flags & TREECHANGE))
146                         nr++;
147                 commit->object.flags |= COUNTED;
148                 p = commit->parents;
149                 entry = p;
150                 if (p) {
151                         p = p->next;
152                         while (p) {
153                                 nr += count_distance(p);
154                                 p = p->next;
155                         }
156                 }
157         }
158
159         return nr;
160 }
161
162 static void clear_distance(struct commit_list *list)
163 {
164         while (list) {
165                 struct commit *commit = list->item;
166                 commit->object.flags &= ~COUNTED;
167                 list = list->next;
168         }
169 }
170
171 static struct commit_list *find_bisection(struct commit_list *list)
172 {
173         int nr, closest;
174         struct commit_list *p, *best;
175
176         nr = 0;
177         p = list;
178         while (p) {
179                 if (!revs.prune_fn || (p->item->object.flags & TREECHANGE))
180                         nr++;
181                 p = p->next;
182         }
183         closest = 0;
184         best = list;
185
186         for (p = list; p; p = p->next) {
187                 int distance;
188
189                 if (revs.prune_fn && !(p->item->object.flags & TREECHANGE))
190                         continue;
191
192                 distance = count_distance(p);
193                 clear_distance(list);
194                 if (nr - distance < distance)
195                         distance = nr - distance;
196                 if (distance > closest) {
197                         best = p;
198                         closest = distance;
199                 }
200         }
201         if (best)
202                 best->next = NULL;
203         return best;
204 }
205
206 static void read_revisions_from_stdin(struct rev_info *revs)
207 {
208         char line[1000];
209
210         while (fgets(line, sizeof(line), stdin) != NULL) {
211                 int len = strlen(line);
212                 if (line[len - 1] == '\n')
213                         line[--len] = 0;
214                 if (!len)
215                         break;
216                 if (line[0] == '-')
217                         die("options not supported in --stdin mode");
218                 if (handle_revision_arg(line, revs, 0, 1))
219                         die("bad revision '%s'", line);
220         }
221 }
222
223 int cmd_rev_list(int argc, const char **argv, const char *prefix)
224 {
225         struct commit_list *list;
226         int i;
227         int read_from_stdin = 0;
228
229         init_revisions(&revs, prefix);
230         revs.abbrev = 0;
231         revs.commit_format = CMIT_FMT_UNSPECIFIED;
232         argc = setup_revisions(argc, argv, &revs, NULL);
233
234         for (i = 1 ; i < argc; i++) {
235                 const char *arg = argv[i];
236
237                 if (!strcmp(arg, "--header")) {
238                         revs.verbose_header = 1;
239                         continue;
240                 }
241                 if (!strcmp(arg, "--timestamp")) {
242                         show_timestamp = 1;
243                         continue;
244                 }
245                 if (!strcmp(arg, "--bisect")) {
246                         bisect_list = 1;
247                         continue;
248                 }
249                 if (!strcmp(arg, "--stdin")) {
250                         if (read_from_stdin++)
251                                 die("--stdin given twice?");
252                         read_revisions_from_stdin(&revs);
253                         continue;
254                 }
255                 usage(rev_list_usage);
256
257         }
258         if (revs.commit_format != CMIT_FMT_UNSPECIFIED) {
259                 /* The command line has a --pretty  */
260                 hdr_termination = '\n';
261                 if (revs.commit_format == CMIT_FMT_ONELINE)
262                         header_prefix = "";
263                 else
264                         header_prefix = "commit ";
265         }
266         else if (revs.verbose_header)
267                 /* Only --header was specified */
268                 revs.commit_format = CMIT_FMT_RAW;
269
270         list = revs.commits;
271
272         if ((!list &&
273              (!(revs.tag_objects||revs.tree_objects||revs.blob_objects) &&
274               !revs.pending.nr)) ||
275             revs.diff)
276                 usage(rev_list_usage);
277
278         save_commit_buffer = revs.verbose_header || revs.grep_filter;
279         track_object_refs = 0;
280         if (bisect_list)
281                 revs.limited = 1;
282
283         prepare_revision_walk(&revs);
284         if (revs.tree_objects)
285                 mark_edges_uninteresting(revs.commits, &revs, show_edge);
286
287         if (bisect_list)
288                 revs.commits = find_bisection(revs.commits);
289
290         traverse_commit_list(&revs, show_commit, show_object);
291
292         return 0;
293 }