git/commit.c
Junio C Hamano 711f6b295c reduce_heads(): protect from duplicate input
Because we do not try computing merge base with itself for obvious
reasons, the code was not prepared for an arguably insane case of
the caller feeding the same commit twice to it.

Noticed and test written by Sverre Hvammen Johansen

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-14 00:09:41 -07:00

779 lines
17 KiB
C

#include "cache.h"
#include "tag.h"
#include "commit.h"
#include "pkt-line.h"
#include "utf8.h"
#include "diff.h"
#include "revision.h"
int save_commit_buffer = 1;
const char *commit_type = "commit";
static struct commit *check_commit(struct object *obj,
const unsigned char *sha1,
int quiet)
{
if (obj->type != OBJ_COMMIT) {
if (!quiet)
error("Object %s is a %s, not a commit",
sha1_to_hex(sha1), typename(obj->type));
return NULL;
}
return (struct commit *) obj;
}
struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
int quiet)
{
struct object *obj = deref_tag(parse_object(sha1), NULL, 0);
if (!obj)
return NULL;
return check_commit(obj, sha1, quiet);
}
struct commit *lookup_commit_reference(const unsigned char *sha1)
{
return lookup_commit_reference_gently(sha1, 0);
}
struct commit *lookup_commit(const unsigned char *sha1)
{
struct object *obj = lookup_object(sha1);
if (!obj)
return create_object(sha1, OBJ_COMMIT, alloc_commit_node());
if (!obj->type)
obj->type = OBJ_COMMIT;
return check_commit(obj, sha1, 0);
}
static unsigned long parse_commit_date(const char *buf, const char *tail)
{
unsigned long date;
const char *dateptr;
if (buf + 6 >= tail)
return 0;
if (memcmp(buf, "author", 6))
return 0;
while (buf < tail && *buf++ != '\n')
/* nada */;
if (buf + 9 >= tail)
return 0;
if (memcmp(buf, "committer", 9))
return 0;
while (buf < tail && *buf++ != '>')
/* nada */;
if (buf >= tail)
return 0;
dateptr = buf;
while (buf < tail && *buf++ != '\n')
/* nada */;
if (buf >= tail)
return 0;
/* dateptr < buf && buf[-1] == '\n', so strtoul will stop at buf-1 */
date = strtoul(dateptr, NULL, 10);
if (date == ULONG_MAX)
date = 0;
return date;
}
static struct commit_graft **commit_graft;
static int commit_graft_alloc, commit_graft_nr;
static int commit_graft_pos(const unsigned char *sha1)
{
int lo, hi;
lo = 0;
hi = commit_graft_nr;
while (lo < hi) {
int mi = (lo + hi) / 2;
struct commit_graft *graft = commit_graft[mi];
int cmp = hashcmp(sha1, graft->sha1);
if (!cmp)
return mi;
if (cmp < 0)
hi = mi;
else
lo = mi + 1;
}
return -lo - 1;
}
int register_commit_graft(struct commit_graft *graft, int ignore_dups)
{
int pos = commit_graft_pos(graft->sha1);
if (0 <= pos) {
if (ignore_dups)
free(graft);
else {
free(commit_graft[pos]);
commit_graft[pos] = graft;
}
return 1;
}
pos = -pos - 1;
if (commit_graft_alloc <= ++commit_graft_nr) {
commit_graft_alloc = alloc_nr(commit_graft_alloc);
commit_graft = xrealloc(commit_graft,
sizeof(*commit_graft) *
commit_graft_alloc);
}
if (pos < commit_graft_nr)
memmove(commit_graft + pos + 1,
commit_graft + pos,
(commit_graft_nr - pos - 1) *
sizeof(*commit_graft));
commit_graft[pos] = graft;
return 0;
}
struct commit_graft *read_graft_line(char *buf, int len)
{
/* The format is just "Commit Parent1 Parent2 ...\n" */
int i;
struct commit_graft *graft = NULL;
if (buf[len-1] == '\n')
buf[--len] = 0;
if (buf[0] == '#' || buf[0] == '\0')
return NULL;
if ((len + 1) % 41) {
bad_graft_data:
error("bad graft data: %s", buf);
free(graft);
return NULL;
}
i = (len + 1) / 41 - 1;
graft = xmalloc(sizeof(*graft) + 20 * i);
graft->nr_parent = i;
if (get_sha1_hex(buf, graft->sha1))
goto bad_graft_data;
for (i = 40; i < len; i += 41) {
if (buf[i] != ' ')
goto bad_graft_data;
if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
goto bad_graft_data;
}
return graft;
}
int read_graft_file(const char *graft_file)
{
FILE *fp = fopen(graft_file, "r");
char buf[1024];
if (!fp)
return -1;
while (fgets(buf, sizeof(buf), fp)) {
/* The format is just "Commit Parent1 Parent2 ...\n" */
int len = strlen(buf);
struct commit_graft *graft = read_graft_line(buf, len);
if (!graft)
continue;
if (register_commit_graft(graft, 1))
error("duplicate graft data: %s", buf);
}
fclose(fp);
return 0;
}
static void prepare_commit_graft(void)
{
static int commit_graft_prepared;
char *graft_file;
if (commit_graft_prepared)
return;
graft_file = get_graft_file();
read_graft_file(graft_file);
/* make sure shallows are read */
is_repository_shallow();
commit_graft_prepared = 1;
}
struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
{
int pos;
prepare_commit_graft();
pos = commit_graft_pos(sha1);
if (pos < 0)
return NULL;
return commit_graft[pos];
}
int write_shallow_commits(int fd, int use_pack_protocol)
{
int i, count = 0;
for (i = 0; i < commit_graft_nr; i++)
if (commit_graft[i]->nr_parent < 0) {
const char *hex =
sha1_to_hex(commit_graft[i]->sha1);
count++;
if (use_pack_protocol)
packet_write(fd, "shallow %s", hex);
else {
if (write_in_full(fd, hex, 40) != 40)
break;
if (write_in_full(fd, "\n", 1) != 1)
break;
}
}
return count;
}
int unregister_shallow(const unsigned char *sha1)
{
int pos = commit_graft_pos(sha1);
if (pos < 0)
return -1;
if (pos + 1 < commit_graft_nr)
memcpy(commit_graft + pos, commit_graft + pos + 1,
sizeof(struct commit_graft *)
* (commit_graft_nr - pos - 1));
commit_graft_nr--;
return 0;
}
int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)
{
char *tail = buffer;
char *bufptr = buffer;
unsigned char parent[20];
struct commit_list **pptr;
struct commit_graft *graft;
if (item->object.parsed)
return 0;
item->object.parsed = 1;
tail += size;
if (tail <= bufptr + 46 || memcmp(bufptr, "tree ", 5) || bufptr[45] != '\n')
return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
if (get_sha1_hex(bufptr + 5, parent) < 0)
return error("bad tree pointer in commit %s",
sha1_to_hex(item->object.sha1));
item->tree = lookup_tree(parent);
bufptr += 46; /* "tree " + "hex sha1" + "\n" */
pptr = &item->parents;
graft = lookup_commit_graft(item->object.sha1);
while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
struct commit *new_parent;
if (tail <= bufptr + 48 ||
get_sha1_hex(bufptr + 7, parent) ||
bufptr[47] != '\n')
return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
bufptr += 48;
if (graft)
continue;
new_parent = lookup_commit(parent);
if (new_parent)
pptr = &commit_list_insert(new_parent, pptr)->next;
}
if (graft) {
int i;
struct commit *new_parent;
for (i = 0; i < graft->nr_parent; i++) {
new_parent = lookup_commit(graft->parent[i]);
if (!new_parent)
continue;
pptr = &commit_list_insert(new_parent, pptr)->next;
}
}
item->date = parse_commit_date(bufptr, tail);
return 0;
}
int parse_commit(struct commit *item)
{
enum object_type type;
void *buffer;
unsigned long size;
int ret;
if (!item)
return -1;
if (item->object.parsed)
return 0;
buffer = read_sha1_file(item->object.sha1, &type, &size);
if (!buffer)
return error("Could not read %s",
sha1_to_hex(item->object.sha1));
if (type != OBJ_COMMIT) {
free(buffer);
return error("Object %s not a commit",
sha1_to_hex(item->object.sha1));
}
ret = parse_commit_buffer(item, buffer, size);
if (save_commit_buffer && !ret) {
item->buffer = buffer;
return 0;
}
free(buffer);
return ret;
}
struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
{
struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
new_list->item = item;
new_list->next = *list_p;
*list_p = new_list;
return new_list;
}
unsigned commit_list_count(const struct commit_list *l)
{
unsigned c = 0;
for (; l; l = l->next )
c++;
return c;
}
void free_commit_list(struct commit_list *list)
{
while (list) {
struct commit_list *temp = list;
list = temp->next;
free(temp);
}
}
struct commit_list * insert_by_date(struct commit *item, struct commit_list **list)
{
struct commit_list **pp = list;
struct commit_list *p;
while ((p = *pp) != NULL) {
if (p->item->date < item->date) {
break;
}
pp = &p->next;
}
return commit_list_insert(item, pp);
}
void sort_by_date(struct commit_list **list)
{
struct commit_list *ret = NULL;
while (*list) {
insert_by_date((*list)->item, &ret);
*list = (*list)->next;
}
*list = ret;
}
struct commit *pop_most_recent_commit(struct commit_list **list,
unsigned int mark)
{
struct commit *ret = (*list)->item;
struct commit_list *parents = ret->parents;
struct commit_list *old = *list;
*list = (*list)->next;
free(old);
while (parents) {
struct commit *commit = parents->item;
if (!parse_commit(commit) && !(commit->object.flags & mark)) {
commit->object.flags |= mark;
insert_by_date(commit, list);
}
parents = parents->next;
}
return ret;
}
void clear_commit_marks(struct commit *commit, unsigned int mark)
{
while (commit) {
struct commit_list *parents;
if (!(mark & commit->object.flags))
return;
commit->object.flags &= ~mark;
parents = commit->parents;
if (!parents)
return;
while ((parents = parents->next))
clear_commit_marks(parents->item, mark);
commit = commit->parents->item;
}
}
struct commit *pop_commit(struct commit_list **stack)
{
struct commit_list *top = *stack;
struct commit *item = top ? top->item : NULL;
if (top) {
*stack = top->next;
free(top);
}
return item;
}
/*
* Performs an in-place topological sort on the list supplied.
*/
void sort_in_topological_order(struct commit_list ** list, int lifo)
{
struct commit_list *next, *orig = *list;
struct commit_list *work, **insert;
struct commit_list **pptr;
if (!orig)
return;
*list = NULL;
/* Mark them and clear the indegree */
for (next = orig; next; next = next->next) {
struct commit *commit = next->item;
commit->object.flags |= TOPOSORT;
commit->indegree = 0;
}
/* update the indegree */
for (next = orig; next; next = next->next) {
struct commit_list * parents = next->item->parents;
while (parents) {
struct commit *parent = parents->item;
if (parent->object.flags & TOPOSORT)
parent->indegree++;
parents = parents->next;
}
}
/*
* find the tips
*
* tips are nodes not reachable from any other node in the list
*
* the tips serve as a starting set for the work queue.
*/
work = NULL;
insert = &work;
for (next = orig; next; next = next->next) {
struct commit *commit = next->item;
if (!commit->indegree)
insert = &commit_list_insert(commit, insert)->next;
}
/* process the list in topological order */
if (!lifo)
sort_by_date(&work);
pptr = list;
*list = NULL;
while (work) {
struct commit *commit;
struct commit_list *parents, *work_item;
work_item = work;
work = work_item->next;
work_item->next = NULL;
commit = work_item->item;
for (parents = commit->parents; parents ; parents = parents->next) {
struct commit *parent=parents->item;
if (!(parent->object.flags & TOPOSORT))
continue;
/*
* parents are only enqueued for emission
* when all their children have been emitted thereby
* guaranteeing topological order.
*/
if (!--parent->indegree) {
if (!lifo)
insert_by_date(parent, &work);
else
commit_list_insert(parent, &work);
}
}
/*
* work_item is a commit all of whose children
* have already been emitted. we can emit it now.
*/
commit->object.flags &= ~TOPOSORT;
*pptr = work_item;
pptr = &work_item->next;
}
}
/* merge-base stuff */
/* bits #0..15 in revision.h */
#define PARENT1 (1u<<16)
#define PARENT2 (1u<<17)
#define STALE (1u<<18)
#define RESULT (1u<<19)
static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
static struct commit *interesting(struct commit_list *list)
{
while (list) {
struct commit *commit = list->item;
list = list->next;
if (commit->object.flags & STALE)
continue;
return commit;
}
return NULL;
}
static struct commit_list *merge_bases_many(struct commit *one, int n, struct commit **twos)
{
struct commit_list *list = NULL;
struct commit_list *result = NULL;
int i;
for (i = 0; i < n; i++) {
if (one == twos[i])
/*
* We do not mark this even with RESULT so we do not
* have to clean it up.
*/
return commit_list_insert(one, &result);
}
if (parse_commit(one))
return NULL;
for (i = 0; i < n; i++) {
if (parse_commit(twos[i]))
return NULL;
}
one->object.flags |= PARENT1;
insert_by_date(one, &list);
for (i = 0; i < n; i++) {
twos[i]->object.flags |= PARENT2;
insert_by_date(twos[i], &list);
}
while (interesting(list)) {
struct commit *commit;
struct commit_list *parents;
struct commit_list *n;
int flags;
commit = list->item;
n = list->next;
free(list);
list = n;
flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
if (flags == (PARENT1 | PARENT2)) {
if (!(commit->object.flags & RESULT)) {
commit->object.flags |= RESULT;
insert_by_date(commit, &result);
}
/* Mark parents of a found merge stale */
flags |= STALE;
}
parents = commit->parents;
while (parents) {
struct commit *p = parents->item;
parents = parents->next;
if ((p->object.flags & flags) == flags)
continue;
if (parse_commit(p))
return NULL;
p->object.flags |= flags;
insert_by_date(p, &list);
}
}
/* Clean up the result to remove stale ones */
free_commit_list(list);
list = result; result = NULL;
while (list) {
struct commit_list *n = list->next;
if (!(list->item->object.flags & STALE))
insert_by_date(list->item, &result);
free(list);
list = n;
}
return result;
}
struct commit_list *get_octopus_merge_bases(struct commit_list *in)
{
struct commit_list *i, *j, *k, *ret = NULL;
struct commit_list **pptr = &ret;
for (i = in; i; i = i->next) {
if (!ret)
pptr = &commit_list_insert(i->item, pptr)->next;
else {
struct commit_list *new = NULL, *end = NULL;
for (j = ret; j; j = j->next) {
struct commit_list *bases;
bases = get_merge_bases(i->item, j->item, 1);
if (!new)
new = bases;
else
end->next = bases;
for (k = bases; k; k = k->next)
end = k;
}
ret = new;
}
}
return ret;
}
struct commit_list *get_merge_bases_many(struct commit *one,
int n,
struct commit **twos,
int cleanup)
{
struct commit_list *list;
struct commit **rslt;
struct commit_list *result;
int cnt, i, j;
result = merge_bases_many(one, n, twos);
for (i = 0; i < n; i++) {
if (one == twos[i])
return result;
}
if (!result || !result->next) {
if (cleanup) {
clear_commit_marks(one, all_flags);
for (i = 0; i < n; i++)
clear_commit_marks(twos[i], all_flags);
}
return result;
}
/* There are more than one */
cnt = 0;
list = result;
while (list) {
list = list->next;
cnt++;
}
rslt = xcalloc(cnt, sizeof(*rslt));
for (list = result, i = 0; list; list = list->next)
rslt[i++] = list->item;
free_commit_list(result);
clear_commit_marks(one, all_flags);
for (i = 0; i < n; i++)
clear_commit_marks(twos[i], all_flags);
for (i = 0; i < cnt - 1; i++) {
for (j = i+1; j < cnt; j++) {
if (!rslt[i] || !rslt[j])
continue;
result = merge_bases_many(rslt[i], 1, &rslt[j]);
clear_commit_marks(rslt[i], all_flags);
clear_commit_marks(rslt[j], all_flags);
for (list = result; list; list = list->next) {
if (rslt[i] == list->item)
rslt[i] = NULL;
if (rslt[j] == list->item)
rslt[j] = NULL;
}
}
}
/* Surviving ones in rslt[] are the independent results */
result = NULL;
for (i = 0; i < cnt; i++) {
if (rslt[i])
insert_by_date(rslt[i], &result);
}
free(rslt);
return result;
}
struct commit_list *get_merge_bases(struct commit *one, struct commit *two,
int cleanup)
{
return get_merge_bases_many(one, 1, &two, cleanup);
}
int in_merge_bases(struct commit *commit, struct commit **reference, int num)
{
struct commit_list *bases, *b;
int ret = 0;
if (num == 1)
bases = get_merge_bases(commit, *reference, 1);
else
die("not yet");
for (b = bases; b; b = b->next) {
if (!hashcmp(commit->object.sha1, b->item->object.sha1)) {
ret = 1;
break;
}
}
free_commit_list(bases);
return ret;
}
struct commit_list *reduce_heads(struct commit_list *heads)
{
struct commit_list *p;
struct commit_list *result = NULL, **tail = &result;
struct commit **other;
size_t num_head, num_other;
if (!heads)
return NULL;
/* Avoid unnecessary reallocations */
for (p = heads, num_head = 0; p; p = p->next)
num_head++;
other = xcalloc(sizeof(*other), num_head);
/* For each commit, see if it can be reached by others */
for (p = heads; p; p = p->next) {
struct commit_list *q, *base;
/* Do we already have this in the result? */
for (q = result; q; q = q->next)
if (p->item == q->item)
break;
if (q)
continue;
num_other = 0;
for (q = heads; q; q = q->next) {
if (p->item == q->item)
continue;
other[num_other++] = q->item;
}
if (num_other)
base = get_merge_bases_many(p->item, num_other, other, 1);
else
base = NULL;
/*
* If p->item does not have anything common with other
* commits, there won't be any merge base. If it is
* reachable from some of the others, p->item will be
* the merge base. If its history is connected with
* others, but p->item is not reachable by others, we
* will get something other than p->item back.
*/
if (!base || (base->item != p->item))
tail = &(commit_list_insert(p->item, tail)->next);
free_commit_list(base);
}
free(other);
return result;
}