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 compare_ref_name(const void *a_, const void *b_)
 145 {
 146         const char * const*a = a_, * const*b = b_;
 147         return strcmp(*a, *b);
 148 }
 149
 150 static void sort_ref_range(int bottom, int top)
 151 {
 152         qsort(ref_name + bottom, top - bottom, sizeof(ref_name[0]),
 153               compare_ref_name);
 154 }
 155
 156 static int append_ref(const char *refname, const unsigned char *sha1)
 157 {
 158         struct commit *commit = lookup_commit_reference_gently(sha1, 1);
 159         if (!commit)
 160                 return 0;
 161         if (MAX_REVS < ref_name_cnt) {
 162                 fprintf(stderr, "warning: ignoring %s; "
 163                         "cannot handle more than %d refs",
 164                         refname, MAX_REVS);
 165                 return 0;
 166         }
 167         ref_name[ref_name_cnt++] = strdup(refname);
 168         ref_name[ref_name_cnt] = NULL;
 169         return 0;
 170 }
 171
 172 static int append_head_ref(const char *refname, const unsigned char *sha1)
 173 {
 174         if (strncmp(refname, "refs/heads/", 11))
 175                 return 0;
 176         return append_ref(refname + 11, sha1);
 177 }
 178
 179 static int append_tag_ref(const char *refname, const unsigned char *sha1)
 180 {
 181         if (strncmp(refname, "refs/tags/", 10))
 182                 return 0;
 183         return append_ref(refname + 5, sha1);
 184 }
 185
 186 static void snarf_refs(int head, int tag)
 187 {
 188         if (head) {
 189                 int orig_cnt = ref_name_cnt;
 190                 for_each_ref(append_head_ref);
 191                 sort_ref_range(orig_cnt, ref_name_cnt);
 192         }
 193         if (tag) {
 194                 int orig_cnt = ref_name_cnt;
 195                 for_each_ref(append_tag_ref);
 196                 sort_ref_range(orig_cnt, ref_name_cnt);
 197         }
 198 }
 199
 200 static int rev_is_head(char *head_path, int headlen,
 201                        char *name,
 202                        unsigned char *head_sha1, unsigned char *sha1)
 203 {
 204         int namelen;
 205         if ((!head_path[0]) || memcmp(head_sha1, sha1, 20))
 206                 return 0;
 207         namelen = strlen(name);
 208         if ((headlen < namelen) ||
 209             memcmp(head_path + headlen - namelen, name, namelen))
 210                 return 0;
 211         if (headlen == namelen ||
 212             head_path[headlen - namelen - 1] == '/')
 213                 return 1;
 214         return 0;
 215 }
 216
 217 static int show_merge_base(struct commit_list *seen, int num_rev)
 218 {
 219         int all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
 220         int all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
 221
 222         while (seen) {
 223                 struct commit *commit = pop_one_commit(&seen);
 224                 int flags = commit->object.flags & all_mask;
 225                 if (!(flags & UNINTERESTING) &&
 226                     ((flags & all_revs) == all_revs)) {
 227                         puts(sha1_to_hex(commit->object.sha1));
 228                         return 0;
 229                 }
 230         }
 231         return 1;
 232 }
 233
 234 int main(int ac, char **av)
 235 {
 236         struct commit *rev[MAX_REVS], *commit;
 237         struct commit_list *list = NULL, *seen = NULL;
 238         int num_rev, i, extra = 0;
 239         int all_heads = 0, all_tags = 0;
 240         char head_path[128];
 241         int head_path_len;
 242         unsigned char head_sha1[20];
 243         int merge_base = 0;
 244         char **label;
 245
 246         while (1 < ac && av[1][0] == '-') {
 247                 char *arg = av[1];
 248                 if (!strcmp(arg, "--all"))
 249                         all_heads = all_tags = 1;
 250                 else if (!strcmp(arg, "--heads"))
 251                         all_heads = 1;
 252                 else if (!strcmp(arg, "--tags"))
 253                         all_tags = 1;
 254                 else if (!strcmp(arg, "--more"))
 255                         extra = 1;
 256                 else if (!strncmp(arg, "--more=", 7)) {
 257                         extra = atoi(arg + 7);
 258                         if (extra < 0)
 259                                 usage(show_branch_usage);
 260                 }
 261                 else if (!strcmp(arg, "--merge-base"))
 262                         merge_base = 1;
 263                 else
 264                         usage(show_branch_usage);
 265                 ac--; av++;
 266         }
 267         ac--; av++;
 268
 269         if (all_heads + all_tags)
 270                 snarf_refs(all_heads, all_tags);
 271
 272         while (0 < ac) {
 273                 unsigned char revkey[20];
 274                 if (get_sha1(*av, revkey))
 275                         die("bad sha1 reference %s", *av);
 276                 append_ref(*av, revkey);
 277                 ac--; av++;
 278         }
 279
 280         /* If still no revs, then add heads */
 281         if (!ref_name_cnt)
 282                 snarf_refs(1, 0);
 283
 284         for (num_rev = 0; ref_name[num_rev]; num_rev++) {
 285                 unsigned char revkey[20];
 286
 287                 if (MAX_REVS <= num_rev)
 288                         die("cannot handle more than %d revs.", MAX_REVS);
 289                 if (get_sha1(ref_name[num_rev], revkey))
 290                         usage(show_branch_usage);
 291                 commit = lookup_commit_reference(revkey);
 292                 if (!commit)
 293                         die("cannot find commit %s (%s)",
 294                             ref_name[num_rev], revkey);
 295                 parse_commit(commit);
 296                 if (!commit->object.util)
 297                         name_commit(commit, num_rev, 0);
 298                 mark_seen(commit, &seen);
 299
 300                 /* rev#0 uses bit REV_SHIFT, rev#1 uses bit REV_SHIFT+1,
 301                  * and so on.  REV_SHIFT bits from bit 0 are used for
 302                  * internal bookkeeping.
 303                  */
 304                 commit->object.flags |= 1u << (num_rev + REV_SHIFT);
 305                 insert_by_date(commit, &list);
 306                 rev[num_rev] = commit;
 307         }
 308         join_revs(&list, &seen, num_rev, extra);
 309
 310         head_path_len = readlink(".git/HEAD", head_path, sizeof(head_path)-1);
 311         if ((head_path_len < 0) || get_sha1("HEAD", head_sha1))
 312                 head_path[0] = 0;
 313         else
 314                 head_path[head_path_len] = 0;
 315
 316         if (merge_base)
 317                 return show_merge_base(seen, num_rev);
 318
 319         /* Show list */
 320         if (1 < num_rev) {
 321                 for (i = 0; i < num_rev; i++) {
 322                         int j;
 323                         int is_head = rev_is_head(head_path,
 324                                                   head_path_len,
 325                                                   ref_name[i],
 326                                                   head_sha1,
 327                                                   rev[i]->object.sha1);
 328                         for (j = 0; j < i; j++)
 329                                 putchar(' ');
 330                         printf("%c [%s] ", is_head ? '*' : '!', ref_name[i]);
 331                         show_one_commit(rev[i], NULL);
 332                 }
 333                 for (i = 0; i < num_rev; i++)
 334                         putchar('-');
 335                 putchar('\n');
 336         }
 337
 338         label = ref_name;
 339         while (seen) {
 340                 struct commit *commit = pop_one_commit(&seen);
 341                 int this_flag = commit->object.flags;
 342                 static char *obvious[] = { "" };
 343
 344                 if ((this_flag & UNINTERESTING) && (--extra < 0))
 345                         break;
 346                 if (1 < num_rev) {
 347                         for (i = 0; i < num_rev; i++)
 348                                 putchar((this_flag & (1u << (i + REV_SHIFT)))
 349                                         ? '+' : ' ');
 350                         putchar(' ');
 351                 }
 352                 show_one_commit(commit, label);
 353                 if (num_rev == 1)
 354                         label = obvious;
 355         }
 356         return 0;
 357 }