fast-export: avoid NULL pointer arithmetic
[git] / builtin / name-rev.c
1 #include "builtin.h"
2 #include "cache.h"
3 #include "commit.h"
4 #include "tag.h"
5 #include "refs.h"
6 #include "parse-options.h"
7 #include "sha1-lookup.h"
8
9 #define CUTOFF_DATE_SLOP 86400 /* one day */
10
11 typedef struct rev_name {
12         const char *tip_name;
13         unsigned long taggerdate;
14         int generation;
15         int distance;
16 } rev_name;
17
18 static long cutoff = LONG_MAX;
19
20 /* How many generations are maximally preferred over _one_ merge traversal? */
21 #define MERGE_TRAVERSAL_WEIGHT 65535
22
23 static void name_rev(struct commit *commit,
24                 const char *tip_name, unsigned long taggerdate,
25                 int generation, int distance,
26                 int deref)
27 {
28         struct rev_name *name = (struct rev_name *)commit->util;
29         struct commit_list *parents;
30         int parent_number = 1;
31
32         parse_commit(commit);
33
34         if (commit->date < cutoff)
35                 return;
36
37         if (deref) {
38                 tip_name = xstrfmt("%s^0", tip_name);
39
40                 if (generation)
41                         die("generation: %d, but deref?", generation);
42         }
43
44         if (name == NULL) {
45                 name = xmalloc(sizeof(rev_name));
46                 commit->util = name;
47                 goto copy_data;
48         } else if (name->taggerdate > taggerdate ||
49                         (name->taggerdate == taggerdate &&
50                          name->distance > distance)) {
51 copy_data:
52                 name->tip_name = tip_name;
53                 name->taggerdate = taggerdate;
54                 name->generation = generation;
55                 name->distance = distance;
56         } else
57                 return;
58
59         for (parents = commit->parents;
60                         parents;
61                         parents = parents->next, parent_number++) {
62                 if (parent_number > 1) {
63                         size_t len;
64                         char *new_name;
65
66                         strip_suffix(tip_name, "^0", &len);
67                         if (generation > 0)
68                                 new_name = xstrfmt("%.*s~%d^%d", (int)len, tip_name,
69                                                    generation, parent_number);
70                         else
71                                 new_name = xstrfmt("%.*s^%d", (int)len, tip_name,
72                                                    parent_number);
73
74                         name_rev(parents->item, new_name, taggerdate, 0,
75                                 distance + MERGE_TRAVERSAL_WEIGHT, 0);
76                 } else {
77                         name_rev(parents->item, tip_name, taggerdate,
78                                 generation + 1, distance + 1, 0);
79                 }
80         }
81 }
82
83 static int subpath_matches(const char *path, const char *filter)
84 {
85         const char *subpath = path;
86
87         while (subpath) {
88                 if (!wildmatch(filter, subpath, 0, NULL))
89                         return subpath - path;
90                 subpath = strchr(subpath, '/');
91                 if (subpath)
92                         subpath++;
93         }
94         return -1;
95 }
96
97 static const char *name_ref_abbrev(const char *refname, int shorten_unambiguous)
98 {
99         if (shorten_unambiguous)
100                 refname = shorten_unambiguous_ref(refname, 0);
101         else if (starts_with(refname, "refs/heads/"))
102                 refname = refname + 11;
103         else if (starts_with(refname, "refs/"))
104                 refname = refname + 5;
105         return refname;
106 }
107
108 struct name_ref_data {
109         int tags_only;
110         int name_only;
111         const char *ref_filter;
112 };
113
114 static struct tip_table {
115         struct tip_table_entry {
116                 unsigned char sha1[20];
117                 const char *refname;
118         } *table;
119         int nr;
120         int alloc;
121         int sorted;
122 } tip_table;
123
124 static void add_to_tip_table(const unsigned char *sha1, const char *refname,
125                              int shorten_unambiguous)
126 {
127         refname = name_ref_abbrev(refname, shorten_unambiguous);
128
129         ALLOC_GROW(tip_table.table, tip_table.nr + 1, tip_table.alloc);
130         hashcpy(tip_table.table[tip_table.nr].sha1, sha1);
131         tip_table.table[tip_table.nr].refname = xstrdup(refname);
132         tip_table.nr++;
133         tip_table.sorted = 0;
134 }
135
136 static int tipcmp(const void *a_, const void *b_)
137 {
138         const struct tip_table_entry *a = a_, *b = b_;
139         return hashcmp(a->sha1, b->sha1);
140 }
141
142 static int name_ref(const char *path, const struct object_id *oid, int flags, void *cb_data)
143 {
144         struct object *o = parse_object(oid->hash);
145         struct name_ref_data *data = cb_data;
146         int can_abbreviate_output = data->tags_only && data->name_only;
147         int deref = 0;
148         unsigned long taggerdate = ULONG_MAX;
149
150         if (data->tags_only && !starts_with(path, "refs/tags/"))
151                 return 0;
152
153         if (data->ref_filter) {
154                 switch (subpath_matches(path, data->ref_filter)) {
155                 case -1: /* did not match */
156                         return 0;
157                 case 0:  /* matched fully */
158                         break;
159                 default: /* matched subpath */
160                         can_abbreviate_output = 1;
161                         break;
162                 }
163         }
164
165         add_to_tip_table(oid->hash, path, can_abbreviate_output);
166
167         while (o && o->type == OBJ_TAG) {
168                 struct tag *t = (struct tag *) o;
169                 if (!t->tagged)
170                         break; /* broken repository */
171                 o = parse_object(t->tagged->oid.hash);
172                 deref = 1;
173                 taggerdate = t->date;
174         }
175         if (o && o->type == OBJ_COMMIT) {
176                 struct commit *commit = (struct commit *)o;
177
178                 path = name_ref_abbrev(path, can_abbreviate_output);
179                 name_rev(commit, xstrdup(path), taggerdate, 0, 0, deref);
180         }
181         return 0;
182 }
183
184 static const unsigned char *nth_tip_table_ent(size_t ix, void *table_)
185 {
186         struct tip_table_entry *table = table_;
187         return table[ix].sha1;
188 }
189
190 static const char *get_exact_ref_match(const struct object *o)
191 {
192         int found;
193
194         if (!tip_table.table || !tip_table.nr)
195                 return NULL;
196
197         if (!tip_table.sorted) {
198                 qsort(tip_table.table, tip_table.nr, sizeof(*tip_table.table),
199                       tipcmp);
200                 tip_table.sorted = 1;
201         }
202
203         found = sha1_pos(o->oid.hash, tip_table.table, tip_table.nr,
204                          nth_tip_table_ent);
205         if (0 <= found)
206                 return tip_table.table[found].refname;
207         return NULL;
208 }
209
210 /* returns a static buffer */
211 static const char *get_rev_name(const struct object *o)
212 {
213         static char buffer[1024];
214         struct rev_name *n;
215         struct commit *c;
216
217         if (o->type != OBJ_COMMIT)
218                 return get_exact_ref_match(o);
219         c = (struct commit *) o;
220         n = c->util;
221         if (!n)
222                 return NULL;
223
224         if (!n->generation)
225                 return n->tip_name;
226         else {
227                 int len = strlen(n->tip_name);
228                 if (len > 2 && !strcmp(n->tip_name + len - 2, "^0"))
229                         len -= 2;
230                 snprintf(buffer, sizeof(buffer), "%.*s~%d", len, n->tip_name,
231                                 n->generation);
232
233                 return buffer;
234         }
235 }
236
237 static void show_name(const struct object *obj,
238                       const char *caller_name,
239                       int always, int allow_undefined, int name_only)
240 {
241         const char *name;
242         const struct object_id *oid = &obj->oid;
243
244         if (!name_only)
245                 printf("%s ", caller_name ? caller_name : oid_to_hex(oid));
246         name = get_rev_name(obj);
247         if (name)
248                 printf("%s\n", name);
249         else if (allow_undefined)
250                 printf("undefined\n");
251         else if (always)
252                 printf("%s\n", find_unique_abbrev(oid->hash, DEFAULT_ABBREV));
253         else
254                 die("cannot describe '%s'", oid_to_hex(oid));
255 }
256
257 static char const * const name_rev_usage[] = {
258         N_("git name-rev [<options>] <commit>..."),
259         N_("git name-rev [<options>] --all"),
260         N_("git name-rev [<options>] --stdin"),
261         NULL
262 };
263
264 static void name_rev_line(char *p, struct name_ref_data *data)
265 {
266         int forty = 0;
267         char *p_start;
268         for (p_start = p; *p; p++) {
269 #define ishex(x) (isdigit((x)) || ((x) >= 'a' && (x) <= 'f'))
270                 if (!ishex(*p))
271                         forty = 0;
272                 else if (++forty == 40 &&
273                          !ishex(*(p+1))) {
274                         unsigned char sha1[40];
275                         const char *name = NULL;
276                         char c = *(p+1);
277                         int p_len = p - p_start + 1;
278
279                         forty = 0;
280
281                         *(p+1) = 0;
282                         if (!get_sha1(p - 39, sha1)) {
283                                 struct object *o =
284                                         lookup_object(sha1);
285                                 if (o)
286                                         name = get_rev_name(o);
287                         }
288                         *(p+1) = c;
289
290                         if (!name)
291                                 continue;
292
293                         if (data->name_only)
294                                 printf("%.*s%s", p_len - 40, p_start, name);
295                         else
296                                 printf("%.*s (%s)", p_len, p_start, name);
297                         p_start = p + 1;
298                 }
299         }
300
301         /* flush */
302         if (p_start != p)
303                 fwrite(p_start, p - p_start, 1, stdout);
304 }
305
306 int cmd_name_rev(int argc, const char **argv, const char *prefix)
307 {
308         struct object_array revs = OBJECT_ARRAY_INIT;
309         int all = 0, transform_stdin = 0, allow_undefined = 1, always = 0, peel_tag = 0;
310         struct name_ref_data data = { 0, 0, NULL };
311         struct option opts[] = {
312                 OPT_BOOL(0, "name-only", &data.name_only, N_("print only names (no SHA-1)")),
313                 OPT_BOOL(0, "tags", &data.tags_only, N_("only use tags to name the commits")),
314                 OPT_STRING(0, "refs", &data.ref_filter, N_("pattern"),
315                                    N_("only use refs matching <pattern>")),
316                 OPT_GROUP(""),
317                 OPT_BOOL(0, "all", &all, N_("list all commits reachable from all refs")),
318                 OPT_BOOL(0, "stdin", &transform_stdin, N_("read from stdin")),
319                 OPT_BOOL(0, "undefined", &allow_undefined, N_("allow to print `undefined` names (default)")),
320                 OPT_BOOL(0, "always",     &always,
321                            N_("show abbreviated commit object as fallback")),
322                 {
323                         /* A Hidden OPT_BOOL */
324                         OPTION_SET_INT, 0, "peel-tag", &peel_tag, NULL,
325                         N_("dereference tags in the input (internal use)"),
326                         PARSE_OPT_NOARG | PARSE_OPT_HIDDEN, NULL, 1,
327                 },
328                 OPT_END(),
329         };
330
331         git_config(git_default_config, NULL);
332         argc = parse_options(argc, argv, prefix, opts, name_rev_usage, 0);
333         if (all + transform_stdin + !!argc > 1) {
334                 error("Specify either a list, or --all, not both!");
335                 usage_with_options(name_rev_usage, opts);
336         }
337         if (all || transform_stdin)
338                 cutoff = 0;
339
340         for (; argc; argc--, argv++) {
341                 unsigned char sha1[20];
342                 struct object *object;
343                 struct commit *commit;
344
345                 if (get_sha1(*argv, sha1)) {
346                         fprintf(stderr, "Could not get sha1 for %s. Skipping.\n",
347                                         *argv);
348                         continue;
349                 }
350
351                 commit = NULL;
352                 object = parse_object(sha1);
353                 if (object) {
354                         struct object *peeled = deref_tag(object, *argv, 0);
355                         if (peeled && peeled->type == OBJ_COMMIT)
356                                 commit = (struct commit *)peeled;
357                 }
358
359                 if (!object) {
360                         fprintf(stderr, "Could not get object for %s. Skipping.\n",
361                                         *argv);
362                         continue;
363                 }
364
365                 if (commit) {
366                         if (cutoff > commit->date)
367                                 cutoff = commit->date;
368                 }
369
370                 if (peel_tag) {
371                         if (!commit) {
372                                 fprintf(stderr, "Could not get commit for %s. Skipping.\n",
373                                         *argv);
374                                 continue;
375                         }
376                         object = (struct object *)commit;
377                 }
378                 add_object_array(object, *argv, &revs);
379         }
380
381         if (cutoff)
382                 cutoff = cutoff - CUTOFF_DATE_SLOP;
383         for_each_ref(name_ref, &data);
384
385         if (transform_stdin) {
386                 char buffer[2048];
387
388                 while (!feof(stdin)) {
389                         char *p = fgets(buffer, sizeof(buffer), stdin);
390                         if (!p)
391                                 break;
392                         name_rev_line(p, &data);
393                 }
394         } else if (all) {
395                 int i, max;
396
397                 max = get_max_object_index();
398                 for (i = 0; i < max; i++) {
399                         struct object *obj = get_indexed_object(i);
400                         if (!obj || obj->type != OBJ_COMMIT)
401                                 continue;
402                         show_name(obj, NULL,
403                                   always, allow_undefined, data.name_only);
404                 }
405         } else {
406                 int i;
407                 for (i = 0; i < revs.nr; i++)
408                         show_name(revs.objects[i].item, revs.objects[i].name,
409                                   always, allow_undefined, data.name_only);
410         }
411
412         return 0;
413 }