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#ifndef REVISION_H
#define REVISION_H
/*
* The low 16 bits of the "flags" field shows whether
* a commit is part of the path to the root for that
* parent.
*
* Bit 16 is an internal flag that we've seen the
* definition for this rev, and not just seen it as
* a parent target.
*/
#define marked(rev) ((rev)->flags & 0xffff)
#define SEEN 0x10000
#define USED 0x20000
#define REACHABLE 0x40000
struct parent {
struct revision *parent;
struct parent *next;
};
struct revision {
unsigned int flags;
unsigned char sha1[20];
unsigned long date;
struct parent *parent;
char tag[1];
};
static struct revision **revs;
static int nr_revs, rev_allocs;
static int find_rev(unsigned char *sha1)
{
int first = 0, last = nr_revs;
while (first < last) {
int next = (first + last) / 2;
struct revision *rev = revs[next];
int cmp;
cmp = memcmp(sha1, rev->sha1, 20);
if (!cmp)
return next;
if (cmp < 0) {
last = next;
continue;
}
first = next+1;
}
return -first-1;
}
static struct revision *lookup_rev(unsigned char *sha1, const char *tag)
{
int pos = find_rev(sha1);
struct revision *n;
if (pos >= 0) {
n = revs[pos];
if (strcmp(n->tag, tag))
error("expected tag %s on object %s: got %s", tag, sha1_to_hex(sha1), n->tag);
return n;
}
pos = -pos-1;
if (rev_allocs == nr_revs) {
rev_allocs = alloc_nr(rev_allocs);
revs = realloc(revs, rev_allocs * sizeof(struct revision *));
}
n = malloc(sizeof(struct revision) + strlen(tag));
n->flags = 0;
memcpy(n->sha1, sha1, 20);
n->parent = NULL;
strcpy(n->tag, tag);
/* Insert it into the right place */
memmove(revs + pos + 1, revs + pos, (nr_revs - pos) * sizeof(struct revision *));
revs[pos] = n;
nr_revs++;
return n;
}
static struct revision *add_relationship(struct revision *rev, unsigned char *needs, const char *tag)
{
struct revision *parent_rev = lookup_rev(needs, tag);
struct parent **pp = &rev->parent, *p;
while ((p = *pp) != NULL) {
if (p->parent == parent_rev)
return parent_rev;
pp = &p->next;
}
p = malloc(sizeof(*p));
p->parent = parent_rev;
p->next = NULL;
*pp = p;
return parent_rev;
}
static void mark_reachable(struct revision *rev, unsigned int mask)
{
struct parent *p = rev->parent;
/* If we've been here already, don't bother */
if (rev->flags & mask)
return;
rev->flags |= mask | USED;
while (p) {
mark_reachable(p->parent, mask);
p = p->next;
}
}
static unsigned long parse_commit_date(const char *buf)
{
unsigned long date;
if (memcmp(buf, "author", 6))
return 0;
while (*buf++ != '\n')
/* nada */;
if (memcmp(buf, "committer", 9))
return 0;
while (*buf++ != '>')
/* nada */;
date = strtoul(buf, NULL, 10);
if (date == ULONG_MAX)
date = 0;
return date;
}
static struct revision * parse_commit(unsigned char *sha1)
{
struct revision *rev = lookup_rev(sha1, "commit");
if (!(rev->flags & SEEN)) {
void *buffer, *bufptr;
unsigned long size;
char type[20];
unsigned char parent[20];
rev->flags |= SEEN;
buffer = bufptr = read_sha1_file(sha1, type, &size);
if (!buffer || strcmp(type, "commit"))
die("%s is not a commit object", sha1_to_hex(sha1));
bufptr += 46; /* "tree " + "hex sha1" + "\n" */
while (!memcmp(bufptr, "parent ", 7) && !get_sha1_hex(bufptr+7, parent)) {
add_relationship(rev, parent, "commit");
parse_commit(parent);
bufptr += 48; /* "parent " + "hex sha1" + "\n" */
}
rev->date = parse_commit_date(bufptr);
free(buffer);
}
return rev;
}
#endif /* REVISION_H */
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