show-branch.c

   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         char **label;
 227
 228         while (1 < ac && av[1][0] == '-') {
 229                 char *arg = av[1];
 230                 if (!strcmp(arg, "--all"))
 231                         all_heads = all_tags = 1;
 232                 else if (!strcmp(arg, "--heads"))
 233                         all_heads = 1;
 234                 else if (!strcmp(arg, "--tags"))
 235                         all_tags = 1;
 236                 else if (!strcmp(arg, "--more"))
 237                         extra = 1;
 238                 else if (!strncmp(arg, "--more=", 7)) {
 239                         extra = atoi(arg + 7);
 240                         if (extra < 0)
 241                                 usage(show_branch_usage);
 242                 }
 243                 else if (!strcmp(arg, "--merge-base"))
 244                         merge_base = 1;
 245                 else
 246                         usage(show_branch_usage);
 247                 ac--; av++;
 248         }
 249         ac--; av++;
 250
 251         if (all_heads + all_tags)
 252                 snarf_refs(all_heads, all_tags);
 253
 254         while (0 < ac) {
 255                 unsigned char revkey[20];
 256                 if (get_sha1(*av, revkey))
 257                         die("bad sha1 reference %s", *av);
 258                 append_ref(*av, revkey);
 259                 ac--; av++;
 260         }
 261
 262         /* If still no revs, then add heads */
 263         if (!ref_name_cnt)
 264                 snarf_refs(1, 0);
 265
 266         for (num_rev = 0; ref_name[num_rev]; num_rev++) {
 267                 unsigned char revkey[20];
 268
 269                 if (MAX_REVS <= num_rev)
 270                         die("cannot handle more than %d revs.", MAX_REVS);
 271                 if (get_sha1(ref_name[num_rev], revkey))
 272                         usage(show_branch_usage);
 273                 commit = lookup_commit_reference(revkey);
 274                 if (!commit)
 275                         die("cannot find commit %s (%s)",
 276                             ref_name[num_rev], revkey);
 277                 parse_commit(commit);
 278                 if (!commit->object.util)
 279                         name_commit(commit, num_rev, 0);
 280                 mark_seen(commit, &seen);
 281
 282                 /* rev#0 uses bit REV_SHIFT, rev#1 uses bit REV_SHIFT+1,
 283                  * and so on.  REV_SHIFT bits from bit 0 are used for
 284                  * internal bookkeeping.
 285                  */
 286                 commit->object.flags |= 1u << (num_rev + REV_SHIFT);
 287                 insert_by_date(commit, &list);
 288                 rev[num_rev] = commit;
 289         }
 290         join_revs(&list, &seen, num_rev, extra);
 291
 292         head_path_len = readlink(".git/HEAD", head_path, sizeof(head_path)-1);
 293         if ((head_path_len < 0) || get_sha1("HEAD", head_sha1))
 294                 head_path[0] = 0;
 295         else
 296                 head_path[head_path_len] = 0;
 297
 298         if (merge_base)
 299                 return show_merge_base(seen, num_rev);
 300
 301         /* Show list */
 302         if (1 < num_rev) {
 303                 for (i = 0; i < num_rev; i++) {
 304                         int j;
 305                         int is_head = rev_is_head(head_path,
 306                                                   head_path_len,
 307                                                   ref_name[i],
 308                                                   head_sha1,
 309                                                   rev[i]->object.sha1);
 310                         for (j = 0; j < i; j++)
 311                                 putchar(' ');
 312                         printf("%c [%s] ", is_head ? '*' : '!', ref_name[i]);
 313                         show_one_commit(rev[i], NULL);
 314                 }
 315                 for (i = 0; i < num_rev; i++)
 316                         putchar('-');
 317                 putchar('\n');
 318         }
 319
 320         label = ref_name;
 321         while (seen) {
 322                 struct commit *commit = pop_one_commit(&seen);
 323                 int this_flag = commit->object.flags;
 324                 static char *obvious[] = { "" };
 325
 326                 if ((this_flag & UNINTERESTING) && (--extra < 0))
 327                         break;
 328                 if (1 < num_rev) {
 329                         for (i = 0; i < num_rev; i++)
 330                                 putchar((this_flag & (1u << (i + REV_SHIFT)))
 331                                         ? '+' : ' ');
 332                         putchar(' ');
 333                 }
 334                 show_one_commit(commit, label);
 335                 if (num_rev == 1)
 336                         label = obvious;
 337         }
 338         return 0;
 339 }