Andrew's git - gitweb.git/blob

   1#ifndef REVISION_H
   2#define REVISION_H
   3
   4/*
   5 * The low 16 bits of the "flags" field shows whether
   6 * a commit is part of the path to the root for that
   7 * parent.
   8 *
   9 * Bit 16 is an internal flag that we've seen the
  10 * definition for this rev, and not just seen it as
  11 * a parent target.
  12 */
  13#define marked(rev)     ((rev)->flags & 0xffff)
  14#define SEEN 0x10000
  15#define USED 0x20000
  16#define REACHABLE 0x40000
  17
  18struct parent {
  19        struct revision *parent;
  20        struct parent *next;
  21};
  22
  23struct revision {
  24        unsigned int flags;
  25        unsigned char sha1[20];
  26        unsigned long date;
  27        struct parent *parent;
  28        char tag[1];
  29};
  30
  31static struct revision **revs;
  32static int nr_revs, rev_allocs;
  33
  34static int find_rev(unsigned char *sha1)
  35{
  36        int first = 0, last = nr_revs;
  37
  38        while (first < last) {
  39                int next = (first + last) / 2;
  40                struct revision *rev = revs[next];
  41                int cmp;
  42
  43                cmp = memcmp(sha1, rev->sha1, 20);
  44                if (!cmp)
  45                        return next;
  46                if (cmp < 0) {
  47                        last = next;
  48                        continue;
  49                }
  50                first = next+1;
  51        }
  52        return -first-1;
  53}
  54
  55static struct revision *lookup_rev(unsigned char *sha1, const char *tag)
  56{
  57        int pos = find_rev(sha1);
  58        struct revision *n;
  59
  60        if (pos >= 0) {
  61                n = revs[pos];
  62                if (strcmp(n->tag, tag))
  63                        error("expected tag %s on object %s: got %s", tag, sha1_to_hex(sha1), n->tag);
  64                return n;
  65        }
  66        
  67        pos = -pos-1;
  68
  69        if (rev_allocs == nr_revs) {
  70                rev_allocs = alloc_nr(rev_allocs);
  71                revs = realloc(revs, rev_allocs * sizeof(struct revision *));
  72        }
  73        n = malloc(sizeof(struct revision) + strlen(tag));
  74
  75        n->flags = 0;
  76        memcpy(n->sha1, sha1, 20);
  77        n->parent = NULL;
  78        strcpy(n->tag, tag);
  79
  80        /* Insert it into the right place */
  81        memmove(revs + pos + 1, revs + pos, (nr_revs - pos) * sizeof(struct revision *));
  82        revs[pos] = n;
  83        nr_revs++;
  84
  85        return n;
  86}
  87
  88static struct revision *add_relationship(struct revision *rev, unsigned char *needs, const char *tag)
  89{
  90        struct revision *parent_rev = lookup_rev(needs, tag);
  91        struct parent **pp = &rev->parent, *p;
  92
  93        while ((p = *pp) != NULL) {
  94                if (p->parent == parent_rev)
  95                        return parent_rev;
  96                pp = &p->next;
  97        }
  98
  99        p = malloc(sizeof(*p));
 100        p->parent = parent_rev;
 101        p->next = NULL;
 102        *pp = p;
 103        return parent_rev;
 104}
 105
 106static void mark_reachable(struct revision *rev, unsigned int mask)
 107{
 108        struct parent *p = rev->parent;
 109
 110        /* If we've been here already, don't bother */
 111        if (rev->flags & mask)
 112                return;
 113        rev->flags |= mask | USED;
 114        while (p) {
 115                mark_reachable(p->parent, mask);
 116                p = p->next;
 117        }
 118}
 119
 120static unsigned long parse_commit_date(const char *buf)
 121{
 122        unsigned long date;
 123
 124        if (memcmp(buf, "author", 6))
 125                return 0;
 126        while (*buf++ != '\n')
 127                /* nada */;
 128        if (memcmp(buf, "committer", 9))
 129                return 0;
 130        while (*buf++ != '>')
 131                /* nada */;
 132        date = strtoul(buf, NULL, 10);
 133        if (date == ULONG_MAX)
 134                date = 0;
 135        return date;
 136}
 137
 138static struct revision * parse_commit(unsigned char *sha1)
 139{
 140        struct revision *rev = lookup_rev(sha1, "commit");
 141
 142        if (!(rev->flags & SEEN)) {
 143                void *buffer, *bufptr;
 144                unsigned long size;
 145                char type[20];
 146                unsigned char parent[20];
 147
 148                rev->flags |= SEEN;
 149                buffer = bufptr = read_sha1_file(sha1, type, &size);
 150                if (!buffer || strcmp(type, "commit"))
 151                        die("%s is not a commit object", sha1_to_hex(sha1));
 152                bufptr += 46; /* "tree " + "hex sha1" + "\n" */
 153                while (!memcmp(bufptr, "parent ", 7) && !get_sha1_hex(bufptr+7, parent)) {
 154                        add_relationship(rev, parent, "commit");
 155                        parse_commit(parent);
 156                        bufptr += 48;   /* "parent " + "hex sha1" + "\n" */
 157                }
 158                rev->date = parse_commit_date(bufptr);
 159                free(buffer);
 160        }
 161        return rev;
 162}
 163
 164#endif /* REVISION_H */