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git/commit-reach.c

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#define USE_THE_REPOSITORY_VARIABLE
#include "git-compat-util.h"
#include "commit.h"
#include "commit-graph.h"
#include "decorate.h"
#include "hex.h"
#include "prio-queue.h"
#include "ref-filter.h"
#include "revision.h"
#include "tag.h"
#include "commit-reach.h"
#include "ewah/ewok.h"
/* Remember to update object flag allocation in object.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 int compare_commits_by_gen(const void *_a, const void *_b)
{
const struct commit *a = *(const struct commit * const *)_a;
const struct commit *b = *(const struct commit * const *)_b;
timestamp_t generation_a = commit_graph_generation(a);
timestamp_t generation_b = commit_graph_generation(b);
if (generation_a < generation_b)
return -1;
if (generation_a > generation_b)
return 1;
if (a->date < b->date)
return -1;
if (a->date > b->date)
return 1;
return 0;
}
static int queue_has_nonstale(struct prio_queue *queue)
{
int i;
for (i = 0; i < queue->nr; i++) {
struct commit *commit = queue->array[i].data;
if (!(commit->object.flags & STALE))
return 1;
}
return 0;
}
/* all input commits in one and twos[] must have been parsed! */
static int paint_down_to_common(struct repository *r,
struct commit *one, int n,
struct commit **twos,
timestamp_t min_generation,
int ignore_missing_commits,
struct commit_list **result)
{
struct prio_queue queue = { compare_commits_by_gen_then_commit_date };
int i;
timestamp_t last_gen = GENERATION_NUMBER_INFINITY;
if (!min_generation && !corrected_commit_dates_enabled(r))
queue.compare = compare_commits_by_commit_date;
one->object.flags |= PARENT1;
if (!n) {
commit_list_append(one, result);
return 0;
}
prio_queue_put(&queue, one);
for (i = 0; i < n; i++) {
twos[i]->object.flags |= PARENT2;
prio_queue_put(&queue, twos[i]);
}
while (queue_has_nonstale(&queue)) {
struct commit *commit = prio_queue_get(&queue);
struct commit_list *parents;
int flags;
timestamp_t generation = commit_graph_generation(commit);
if (min_generation && generation > last_gen)
BUG("bad generation skip %"PRItime" > %"PRItime" at %s",
generation, last_gen,
oid_to_hex(&commit->object.oid));
last_gen = generation;
if (generation < min_generation)
break;
flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
if (flags == (PARENT1 | PARENT2)) {
if (!(commit->object.flags & RESULT)) {
commit->object.flags |= RESULT;
commit_list_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 (repo_parse_commit(r, p)) {
clear_prio_queue(&queue);
free_commit_list(*result);
*result = NULL;
/*
* At this stage, we know that the commit is
* missing: `repo_parse_commit()` uses
* `OBJECT_INFO_DIE_IF_CORRUPT` and therefore
* corrupt commits would already have been
* dispatched with a `die()`.
*/
if (ignore_missing_commits)
return 0;
return error(_("could not parse commit %s"),
oid_to_hex(&p->object.oid));
}
p->object.flags |= flags;
prio_queue_put(&queue, p);
}
}
clear_prio_queue(&queue);
return 0;
}
static int merge_bases_many(struct repository *r,
struct commit *one, int n,
struct commit **twos,
struct commit_list **result)
{
struct commit_list *list = 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.
*/
*result = commit_list_insert(one, result);
return 0;
}
}
if (!one)
return 0;
if (repo_parse_commit(r, one))
return error(_("could not parse commit %s"),
oid_to_hex(&one->object.oid));
for (i = 0; i < n; i++) {
if (!twos[i])
return 0;
if (repo_parse_commit(r, twos[i]))
return error(_("could not parse commit %s"),
oid_to_hex(&twos[i]->object.oid));
}
if (paint_down_to_common(r, one, n, twos, 0, 0, &list)) {
free_commit_list(list);
return -1;
}
while (list) {
struct commit *commit = pop_commit(&list);
if (!(commit->object.flags & STALE))
commit_list_insert_by_date(commit, result);
}
return 0;
}
int get_octopus_merge_bases(struct commit_list *in, struct commit_list **result)
{
struct commit_list *i, *j, *k;
if (!in)
return 0;
commit_list_insert(in->item, result);
for (i = in->next; i; i = i->next) {
struct commit_list *new_commits = NULL, *end = NULL;
for (j = *result; j; j = j->next) {
struct commit_list *bases = NULL;
if (repo_get_merge_bases(the_repository, i->item,
j->item, &bases) < 0) {
free_commit_list(bases);
free_commit_list(*result);
*result = NULL;
return -1;
}
if (!new_commits)
new_commits = bases;
else
end->next = bases;
for (k = bases; k; k = k->next)
end = k;
}
free_commit_list(*result);
*result = new_commits;
}
return 0;
}
static int remove_redundant_no_gen(struct repository *r,
struct commit **array, int cnt)
{
struct commit **work;
unsigned char *redundant;
int *filled_index;
int i, j, filled;
CALLOC_ARRAY(work, cnt);
redundant = xcalloc(cnt, 1);
ALLOC_ARRAY(filled_index, cnt - 1);
for (i = 0; i < cnt; i++)
repo_parse_commit(r, array[i]);
for (i = 0; i < cnt; i++) {
struct commit_list *common = NULL;
timestamp_t min_generation = commit_graph_generation(array[i]);
if (redundant[i])
continue;
for (j = filled = 0; j < cnt; j++) {
timestamp_t curr_generation;
if (i == j || redundant[j])
continue;
filled_index[filled] = j;
work[filled++] = array[j];
curr_generation = commit_graph_generation(array[j]);
if (curr_generation < min_generation)
min_generation = curr_generation;
}
if (paint_down_to_common(r, array[i], filled,
work, min_generation, 0, &common)) {
clear_commit_marks(array[i], all_flags);
clear_commit_marks_many(filled, work, all_flags);
free_commit_list(common);
free(work);
free(redundant);
free(filled_index);
return -1;
}
if (array[i]->object.flags & PARENT2)
redundant[i] = 1;
for (j = 0; j < filled; j++)
if (work[j]->object.flags & PARENT1)
redundant[filled_index[j]] = 1;
clear_commit_marks(array[i], all_flags);
clear_commit_marks_many(filled, work, all_flags);
free_commit_list(common);
}
/* Now collect the result */
COPY_ARRAY(work, array, cnt);
for (i = filled = 0; i < cnt; i++)
if (!redundant[i])
array[filled++] = work[i];
free(work);
free(redundant);
free(filled_index);
return filled;
}
static int remove_redundant_with_gen(struct repository *r,
struct commit **array, int cnt)
{
int i, count_non_stale = 0, count_still_independent = cnt;
timestamp_t min_generation = GENERATION_NUMBER_INFINITY;
struct commit **walk_start, **sorted;
size_t walk_start_nr = 0, walk_start_alloc = cnt;
int min_gen_pos = 0;
/*
* Sort the input by generation number, ascending. This allows
* us to increase the "min_generation" limit when we discover
* the commit with lowest generation is STALE. The index
* min_gen_pos points to the current position within 'array'
* that is not yet known to be STALE.
*/
DUP_ARRAY(sorted, array, cnt);
QSORT(sorted, cnt, compare_commits_by_gen);
min_generation = commit_graph_generation(sorted[0]);
ALLOC_ARRAY(walk_start, walk_start_alloc);
/* Mark all parents of the input as STALE */
for (i = 0; i < cnt; i++) {
struct commit_list *parents;
repo_parse_commit(r, array[i]);
array[i]->object.flags |= RESULT;
parents = array[i]->parents;
while (parents) {
repo_parse_commit(r, parents->item);
if (!(parents->item->object.flags & STALE)) {
parents->item->object.flags |= STALE;
ALLOC_GROW(walk_start, walk_start_nr + 1, walk_start_alloc);
walk_start[walk_start_nr++] = parents->item;
}
parents = parents->next;
}
}
QSORT(walk_start, walk_start_nr, compare_commits_by_gen);
/* remove STALE bit for now to allow walking through parents */
for (i = 0; i < walk_start_nr; i++)
walk_start[i]->object.flags &= ~STALE;
/*
* Start walking from the highest generation. Hopefully, it will
* find all other items during the first-parent walk, and we can
* terminate early. Otherwise, we will do the same amount of work
* as before.
*/
for (i = walk_start_nr - 1; i >= 0 && count_still_independent > 1; i--) {
/* push the STALE bits up to min generation */
struct commit_list *stack = NULL;
commit_list_insert(walk_start[i], &stack);
walk_start[i]->object.flags |= STALE;
while (stack) {
struct commit_list *parents;
struct commit *c = stack->item;
repo_parse_commit(r, c);
if (c->object.flags & RESULT) {
c->object.flags &= ~RESULT;
if (--count_still_independent <= 1)
break;
if (oideq(&c->object.oid, &sorted[min_gen_pos]->object.oid)) {
while (min_gen_pos < cnt - 1 &&
(sorted[min_gen_pos]->object.flags & STALE))
min_gen_pos++;
min_generation = commit_graph_generation(sorted[min_gen_pos]);
}
}
if (commit_graph_generation(c) < min_generation) {
pop_commit(&stack);
continue;
}
parents = c->parents;
while (parents) {
if (!(parents->item->object.flags & STALE)) {
parents->item->object.flags |= STALE;
commit_list_insert(parents->item, &stack);
break;
}
parents = parents->next;
}
/* pop if all parents have been visited already */
if (!parents)
pop_commit(&stack);
}
free_commit_list(stack);
}
free(sorted);
/* clear result */
for (i = 0; i < cnt; i++)
array[i]->object.flags &= ~RESULT;
/* rearrange array */
for (i = count_non_stale = 0; i < cnt; i++) {
if (!(array[i]->object.flags & STALE))
array[count_non_stale++] = array[i];
}
/* clear marks */
clear_commit_marks_many(walk_start_nr, walk_start, STALE);
free(walk_start);
return count_non_stale;
}
static int remove_redundant(struct repository *r, struct commit **array, int cnt)
{
/*
* Some commit in the array may be an ancestor of
* another commit. Move the independent commits to the
* beginning of 'array' and return their number. Callers
* should not rely upon the contents of 'array' after
* that number.
*/
if (generation_numbers_enabled(r)) {
int i;
/*
* If we have a single commit with finite generation
* number, then the _with_gen algorithm is preferred.
*/
for (i = 0; i < cnt; i++) {
if (commit_graph_generation(array[i]) < GENERATION_NUMBER_INFINITY)
return remove_redundant_with_gen(r, array, cnt);
}
}
return remove_redundant_no_gen(r, array, cnt);
}
static int get_merge_bases_many_0(struct repository *r,
struct commit *one,
int n,
struct commit **twos,
int cleanup,
struct commit_list **result)
{
struct commit_list *list;
struct commit **rslt;
int cnt, i;
if (merge_bases_many(r, one, n, twos, result) < 0)
return -1;
for (i = 0; i < n; i++) {
if (one == twos[i])
return 0;
}
if (!*result || !(*result)->next) {
if (cleanup) {
clear_commit_marks(one, all_flags);
clear_commit_marks_many(n, twos, all_flags);
}
return 0;
}
/* There are more than one */
cnt = commit_list_count(*result);
CALLOC_ARRAY(rslt, cnt);
for (list = *result, i = 0; list; list = list->next)
rslt[i++] = list->item;
free_commit_list(*result);
*result = NULL;
clear_commit_marks(one, all_flags);
clear_commit_marks_many(n, twos, all_flags);
cnt = remove_redundant(r, rslt, cnt);
if (cnt < 0) {
free(rslt);
return -1;
}
for (i = 0; i < cnt; i++)
commit_list_insert_by_date(rslt[i], result);
free(rslt);
return 0;
}
int repo_get_merge_bases_many(struct repository *r,
struct commit *one,
int n,
struct commit **twos,
struct commit_list **result)
{
return get_merge_bases_many_0(r, one, n, twos, 1, result);
}
int repo_get_merge_bases_many_dirty(struct repository *r,
struct commit *one,
int n,
struct commit **twos,
struct commit_list **result)
{
return get_merge_bases_many_0(r, one, n, twos, 0, result);
}
int repo_get_merge_bases(struct repository *r,
struct commit *one,
struct commit *two,
struct commit_list **result)
{
return get_merge_bases_many_0(r, one, 1, &two, 1, result);
}
/*
* Is "commit" a descendant of one of the elements on the "with_commit" list?
*/
int repo_is_descendant_of(struct repository *r,
struct commit *commit,
struct commit_list *with_commit)
{
if (!with_commit)
return 1;
if (generation_numbers_enabled(r)) {
struct commit_list *from_list = NULL;
int result;
commit_list_insert(commit, &from_list);
result = can_all_from_reach(from_list, with_commit, 0);
free_commit_list(from_list);
return result;
} else {
while (with_commit) {
struct commit *other;
int ret;
other = with_commit->item;
with_commit = with_commit->next;
ret = repo_in_merge_bases_many(r, other, 1, &commit, 0);
if (ret)
return ret;
}
return 0;
}
}
/*
* Is "commit" an ancestor of one of the "references"?
*/
int repo_in_merge_bases_many(struct repository *r, struct commit *commit,
int nr_reference, struct commit **reference,
int ignore_missing_commits)
{
struct commit_list *bases = NULL;
int ret = 0, i;
timestamp_t generation, max_generation = GENERATION_NUMBER_ZERO;
if (repo_parse_commit(r, commit))
return ignore_missing_commits ? 0 : -1;
for (i = 0; i < nr_reference; i++) {
if (repo_parse_commit(r, reference[i]))
return ignore_missing_commits ? 0 : -1;
generation = commit_graph_generation(reference[i]);
if (generation > max_generation)
max_generation = generation;
}
generation = commit_graph_generation(commit);
if (generation > max_generation)
return ret;
if (paint_down_to_common(r, commit,
nr_reference, reference,
generation, ignore_missing_commits, &bases))
ret = -1;
else if (commit->object.flags & PARENT2)
ret = 1;
clear_commit_marks(commit, all_flags);
clear_commit_marks_many(nr_reference, reference, all_flags);
free_commit_list(bases);
return ret;
}
/*
* Is "commit" an ancestor of (i.e. reachable from) the "reference"?
*/
int repo_in_merge_bases(struct repository *r,
struct commit *commit,
struct commit *reference)
{
int res;
struct commit_list *list = NULL;
struct commit_list **next = &list;
next = commit_list_append(commit, next);
res = repo_is_descendant_of(r, reference, list);
free_commit_list(list);
return res;
}
struct commit_list *reduce_heads(struct commit_list *heads)
{
struct commit_list *p;
struct commit_list *result = NULL, **tail = &result;
struct commit **array;
int num_head, i;
if (!heads)
return NULL;
/* Uniquify */
for (p = heads; p; p = p->next)
p->item->object.flags &= ~STALE;
for (p = heads, num_head = 0; p; p = p->next) {
if (p->item->object.flags & STALE)
continue;
p->item->object.flags |= STALE;
num_head++;
}
CALLOC_ARRAY(array, num_head);
for (p = heads, i = 0; p; p = p->next) {
if (p->item->object.flags & STALE) {
array[i++] = p->item;
p->item->object.flags &= ~STALE;
}
}
num_head = remove_redundant(the_repository, array, num_head);
if (num_head < 0) {
free(array);
return NULL;
}
for (i = 0; i < num_head; i++)
tail = &commit_list_insert(array[i], tail)->next;
free(array);
return result;
}
void reduce_heads_replace(struct commit_list **heads)
{
struct commit_list *result = reduce_heads(*heads);
free_commit_list(*heads);
*heads = result;
}
int ref_newer(const struct object_id *new_oid, const struct object_id *old_oid)
{
struct object *o;
struct commit *old_commit, *new_commit;
struct commit_list *old_commit_list = NULL;
int ret;
/*
* Both new_commit and old_commit must be commit-ish and new_commit is descendant of
* old_commit. Otherwise we require --force.
*/
o = deref_tag(the_repository, parse_object(the_repository, old_oid),
NULL, 0);
if (!o || o->type != OBJ_COMMIT)
return 0;
old_commit = (struct commit *) o;
o = deref_tag(the_repository, parse_object(the_repository, new_oid),
NULL, 0);
if (!o || o->type != OBJ_COMMIT)
return 0;
new_commit = (struct commit *) o;
if (repo_parse_commit(the_repository, new_commit) < 0)
return 0;
commit_list_insert(old_commit, &old_commit_list);
ret = repo_is_descendant_of(the_repository,
new_commit, old_commit_list);
if (ret < 0)
exit(128);
free_commit_list(old_commit_list);
return ret;
}
/*
* Mimicking the real stack, this stack lives on the heap, avoiding stack
* overflows.
*
* At each recursion step, the stack items points to the commits whose
* ancestors are to be inspected.
*/
struct contains_stack {
int nr, alloc;
struct contains_stack_entry {
struct commit *commit;
struct commit_list *parents;
} *contains_stack;
};
static int in_commit_list(const struct commit_list *want, struct commit *c)
{
for (; want; want = want->next)
if (oideq(&want->item->object.oid, &c->object.oid))
return 1;
return 0;
}
/*
* Test whether the candidate is contained in the list.
* Do not recurse to find out, though, but return -1 if inconclusive.
*/
static enum contains_result contains_test(struct commit *candidate,
const struct commit_list *want,
struct contains_cache *cache,
timestamp_t cutoff)
{
enum contains_result *cached = contains_cache_at(cache, candidate);
/* If we already have the answer cached, return that. */
if (*cached)
return *cached;
/* or are we it? */
if (in_commit_list(want, candidate)) {
*cached = CONTAINS_YES;
return CONTAINS_YES;
}
/* Otherwise, we don't know; prepare to recurse */
parse_commit_or_die(candidate);
if (commit_graph_generation(candidate) < cutoff)
return CONTAINS_NO;
return CONTAINS_UNKNOWN;
}
static void push_to_contains_stack(struct commit *candidate, struct contains_stack *contains_stack)
{
ALLOC_GROW(contains_stack->contains_stack, contains_stack->nr + 1, contains_stack->alloc);
contains_stack->contains_stack[contains_stack->nr].commit = candidate;
contains_stack->contains_stack[contains_stack->nr++].parents = candidate->parents;
}
static enum contains_result contains_tag_algo(struct commit *candidate,
const struct commit_list *want,
struct contains_cache *cache)
{
struct contains_stack contains_stack = { 0, 0, NULL };
enum contains_result result;
timestamp_t cutoff = GENERATION_NUMBER_INFINITY;
const struct commit_list *p;
for (p = want; p; p = p->next) {
timestamp_t generation;
struct commit *c = p->item;
load_commit_graph_info(the_repository, c);
generation = commit_graph_generation(c);
if (generation < cutoff)
cutoff = generation;
}
result = contains_test(candidate, want, cache, cutoff);
if (result != CONTAINS_UNKNOWN)
return result;
push_to_contains_stack(candidate, &contains_stack);
while (contains_stack.nr) {
struct contains_stack_entry *entry = &contains_stack.contains_stack[contains_stack.nr - 1];
struct commit *commit = entry->commit;
struct commit_list *parents = entry->parents;
if (!parents) {
*contains_cache_at(cache, commit) = CONTAINS_NO;
contains_stack.nr--;
}
/*
* If we just popped the stack, parents->item has been marked,
* therefore contains_test will return a meaningful yes/no.
*/
else switch (contains_test(parents->item, want, cache, cutoff)) {
case CONTAINS_YES:
*contains_cache_at(cache, commit) = CONTAINS_YES;
contains_stack.nr--;
break;
case CONTAINS_NO:
entry->parents = parents->next;
break;
case CONTAINS_UNKNOWN:
push_to_contains_stack(parents->item, &contains_stack);
break;
}
}
free(contains_stack.contains_stack);
return contains_test(candidate, want, cache, cutoff);
}
int commit_contains(struct ref_filter *filter, struct commit *commit,
struct commit_list *list, struct contains_cache *cache)
{
if (filter->with_commit_tag_algo)
return contains_tag_algo(commit, list, cache) == CONTAINS_YES;
return repo_is_descendant_of(the_repository, commit, list);
}
int can_all_from_reach_with_flag(struct object_array *from,
unsigned int with_flag,
unsigned int assign_flag,
time_t min_commit_date,
timestamp_t min_generation)
{
struct commit **list = NULL;
int i;
int nr_commits;
int result = 1;
ALLOC_ARRAY(list, from->nr);
nr_commits = 0;
for (i = 0; i < from->nr; i++) {
struct object *from_one = from->objects[i].item;
if (!from_one || from_one->flags & assign_flag)
continue;
from_one = deref_tag(the_repository, from_one,
"a from object", 0);
if (!from_one || from_one->type != OBJ_COMMIT) {
/*
* no way to tell if this is reachable by
* looking at the ancestry chain alone, so
* leave a note to ourselves not to worry about
* this object anymore.
*/
from->objects[i].item->flags |= assign_flag;
continue;
}
list[nr_commits] = (struct commit *)from_one;
if (repo_parse_commit(the_repository, list[nr_commits]) ||
commit_graph_generation(list[nr_commits]) < min_generation) {
result = 0;
goto cleanup;
}
nr_commits++;
}
QSORT(list, nr_commits, compare_commits_by_gen);
for (i = 0; i < nr_commits; i++) {
/* DFS from list[i] */
struct commit_list *stack = NULL;
list[i]->object.flags |= assign_flag;
commit_list_insert(list[i], &stack);
while (stack) {
struct commit_list *parent;
if (stack->item->object.flags & (with_flag | RESULT)) {
pop_commit(&stack);
if (stack)
stack->item->object.flags |= RESULT;
continue;
}
for (parent = stack->item->parents; parent; parent = parent->next) {
if (parent->item->object.flags & (with_flag | RESULT))
stack->item->object.flags |= RESULT;
if (!(parent->item->object.flags & assign_flag)) {
parent->item->object.flags |= assign_flag;
if (repo_parse_commit(the_repository, parent->item) ||
parent->item->date < min_commit_date ||
commit_graph_generation(parent->item) < min_generation)
continue;
commit_list_insert(parent->item, &stack);
break;
}
}
if (!parent)
pop_commit(&stack);
}
if (!(list[i]->object.flags & (with_flag | RESULT))) {
result = 0;
goto cleanup;
}
}
cleanup:
clear_commit_marks_many(nr_commits, list, RESULT | assign_flag);
free(list);
for (i = 0; i < from->nr; i++) {
struct object *from_one = from->objects[i].item;
if (from_one)
from_one->flags &= ~assign_flag;
}
return result;
}
int can_all_from_reach(struct commit_list *from, struct commit_list *to,
int cutoff_by_min_date)
{
struct object_array from_objs = OBJECT_ARRAY_INIT;
time_t min_commit_date = cutoff_by_min_date ? from->item->date : 0;
struct commit_list *from_iter = from, *to_iter = to;
int result;
timestamp_t min_generation = GENERATION_NUMBER_INFINITY;
while (from_iter) {
add_object_array(&from_iter->item->object, NULL, &from_objs);
if (!repo_parse_commit(the_repository, from_iter->item)) {
timestamp_t generation;
if (from_iter->item->date < min_commit_date)
min_commit_date = from_iter->item->date;
generation = commit_graph_generation(from_iter->item);
if (generation < min_generation)
min_generation = generation;
}
from_iter = from_iter->next;
}
while (to_iter) {
if (!repo_parse_commit(the_repository, to_iter->item)) {
timestamp_t generation;
if (to_iter->item->date < min_commit_date)
min_commit_date = to_iter->item->date;
generation = commit_graph_generation(to_iter->item);
if (generation < min_generation)
min_generation = generation;
}
to_iter->item->object.flags |= PARENT2;
to_iter = to_iter->next;
}
result = can_all_from_reach_with_flag(&from_objs, PARENT2, PARENT1,
min_commit_date, min_generation);
while (from) {
clear_commit_marks(from->item, PARENT1);
from = from->next;
}
while (to) {
clear_commit_marks(to->item, PARENT2);
to = to->next;
}
object_array_clear(&from_objs);
return result;
}
struct commit_list *get_reachable_subset(struct commit **from, int nr_from,
struct commit **to, int nr_to,
unsigned int reachable_flag)
{
struct commit **item;
struct commit *current;
struct commit_list *found_commits = NULL;
struct commit **to_last = to + nr_to;
struct commit **from_last = from + nr_from;
timestamp_t min_generation = GENERATION_NUMBER_INFINITY;
int num_to_find = 0;
struct prio_queue queue = { compare_commits_by_gen_then_commit_date };
for (item = to; item < to_last; item++) {
timestamp_t generation;
struct commit *c = *item;
repo_parse_commit(the_repository, c);
generation = commit_graph_generation(c);
if (generation < min_generation)
min_generation = generation;
if (!(c->object.flags & PARENT1)) {
c->object.flags |= PARENT1;
num_to_find++;
}
}
for (item = from; item < from_last; item++) {
struct commit *c = *item;
if (!(c->object.flags & PARENT2)) {
c->object.flags |= PARENT2;
repo_parse_commit(the_repository, c);
prio_queue_put(&queue, *item);
}
}
while (num_to_find && (current = prio_queue_get(&queue)) != NULL) {
struct commit_list *parents;
if (current->object.flags & PARENT1) {
current->object.flags &= ~PARENT1;
current->object.flags |= reachable_flag;
commit_list_insert(current, &found_commits);
num_to_find--;
}
for (parents = current->parents; parents; parents = parents->next) {
struct commit *p = parents->item;
repo_parse_commit(the_repository, p);
if (commit_graph_generation(p) < min_generation)
continue;
if (p->object.flags & PARENT2)
continue;
p->object.flags |= PARENT2;
prio_queue_put(&queue, p);
}
}
clear_prio_queue(&queue);
clear_commit_marks_many(nr_to, to, PARENT1);
clear_commit_marks_many(nr_from, from, PARENT2);
return found_commits;
}
define_commit_slab(bit_arrays, struct bitmap *);
static struct bit_arrays bit_arrays;
static void insert_no_dup(struct prio_queue *queue, struct commit *c)
{
if (c->object.flags & PARENT2)
return;
prio_queue_put(queue, c);
c->object.flags |= PARENT2;
}
static struct bitmap *get_bit_array(struct commit *c, int width)
{
struct bitmap **bitmap = bit_arrays_at(&bit_arrays, c);
if (!*bitmap)
*bitmap = bitmap_word_alloc(width);
return *bitmap;
}
static void free_bit_array(struct commit *c)
{
struct bitmap **bitmap = bit_arrays_at(&bit_arrays, c);
if (!*bitmap)
return;
bitmap_free(*bitmap);
*bitmap = NULL;
}
void ahead_behind(struct repository *r,
struct commit **commits, size_t commits_nr,
struct ahead_behind_count *counts, size_t counts_nr)
{
struct prio_queue queue = { .compare = compare_commits_by_gen_then_commit_date };
size_t width = DIV_ROUND_UP(commits_nr, BITS_IN_EWORD);
if (!commits_nr || !counts_nr)
return;
for (size_t i = 0; i < counts_nr; i++) {
counts[i].ahead = 0;
counts[i].behind = 0;
}
ensure_generations_valid(r, commits, commits_nr);
init_bit_arrays(&bit_arrays);
for (size_t i = 0; i < commits_nr; i++) {
struct commit *c = commits[i];
struct bitmap *bitmap = get_bit_array(c, width);
bitmap_set(bitmap, i);
insert_no_dup(&queue, c);
}
while (queue_has_nonstale(&queue)) {
struct commit *c = prio_queue_get(&queue);
struct commit_list *p;
struct bitmap *bitmap_c = get_bit_array(c, width);
for (size_t i = 0; i < counts_nr; i++) {
int reach_from_tip = !!bitmap_get(bitmap_c, counts[i].tip_index);
int reach_from_base = !!bitmap_get(bitmap_c, counts[i].base_index);
if (reach_from_tip ^ reach_from_base) {
if (reach_from_base)
counts[i].behind++;
else
counts[i].ahead++;
}
}
for (p = c->parents; p; p = p->next) {
struct bitmap *bitmap_p;
repo_parse_commit(r, p->item);
bitmap_p = get_bit_array(p->item, width);
bitmap_or(bitmap_p, bitmap_c);
/*
* If this parent is reachable from every starting
* commit, then none of its ancestors can contribute
* to the ahead/behind count. Mark it as STALE, so
* we can stop the walk when every commit in the
* queue is STALE.
*/
if (bitmap_popcount(bitmap_p) == commits_nr)
p->item->object.flags |= STALE;
insert_no_dup(&queue, p->item);
}
free_bit_array(c);
}
/* STALE is used here, PARENT2 is used by insert_no_dup(). */
repo_clear_commit_marks(r, PARENT2 | STALE);
while (prio_queue_peek(&queue)) {
struct commit *c = prio_queue_get(&queue);
free_bit_array(c);
}
clear_bit_arrays(&bit_arrays);
clear_prio_queue(&queue);
}
struct commit_and_index {
struct commit *commit;
unsigned int index;
timestamp_t generation;
};
static int compare_commit_and_index_by_generation(const void *va, const void *vb)
{
const struct commit_and_index *a = (const struct commit_and_index *)va;
const struct commit_and_index *b = (const struct commit_and_index *)vb;
if (a->generation > b->generation)
return 1;
if (a->generation < b->generation)
return -1;
return 0;
}
void tips_reachable_from_bases(struct repository *r,
struct commit_list *bases,
struct commit **tips, size_t tips_nr,
int mark)
{
struct commit_and_index *commits;
size_t min_generation_index = 0;
timestamp_t min_generation;
struct commit_list *stack = NULL;
if (!bases || !tips || !tips_nr)
return;
/*
* Do a depth-first search starting at 'bases' to search for the
* tips. Stop at the lowest (un-found) generation number. When
* finding the lowest commit, increase the minimum generation
* number to the next lowest (un-found) generation number.
*/
CALLOC_ARRAY(commits, tips_nr);
for (size_t i = 0; i < tips_nr; i++) {
commits[i].commit = tips[i];
commits[i].index = i;
commits[i].generation = commit_graph_generation(tips[i]);
}
/* Sort with generation number ascending. */
QSORT(commits, tips_nr, compare_commit_and_index_by_generation);
min_generation = commits[0].generation;
while (bases) {
repo_parse_commit(r, bases->item);
commit_list_insert(bases->item, &stack);
bases = bases->next;
}
while (stack) {
int explored_all_parents = 1;
struct commit_list *p;
struct commit *c = stack->item;
timestamp_t c_gen = commit_graph_generation(c);
/* Does it match any of our tips? */
for (size_t j = min_generation_index; j < tips_nr; j++) {
if (c_gen < commits[j].generation)
break;
if (commits[j].commit == c) {
tips[commits[j].index]->object.flags |= mark;
if (j == min_generation_index) {
unsigned int k = j + 1;
while (k < tips_nr &&
(tips[commits[k].index]->object.flags & mark))
k++;
/* Terminate early if all found. */
if (k >= tips_nr)
goto done;
min_generation_index = k;
min_generation = commits[k].generation;
}
}
}
for (p = c->parents; p; p = p->next) {
repo_parse_commit(r, p->item);
/* Have we already explored this parent? */
if (p->item->object.flags & SEEN)
continue;
/* Is it below the current minimum generation? */
if (commit_graph_generation(p->item) < min_generation)
continue;
/* Ok, we will explore from here on. */
p->item->object.flags |= SEEN;
explored_all_parents = 0;
commit_list_insert(p->item, &stack);
break;
}
if (explored_all_parents)
pop_commit(&stack);
}
done:
free(commits);
repo_clear_commit_marks(r, SEEN);
free_commit_list(stack);
}
/*
* This slab initializes integers to zero, so use "-1" for "tip is best" and
* "i + 1" for "bases[i] is best".
*/
define_commit_slab(best_branch_base, int);
static struct best_branch_base best_branch_base;
#define get_best(c) (*best_branch_base_at(&best_branch_base, (c)))
#define set_best(c,v) (*best_branch_base_at(&best_branch_base, (c)) = (v))
int get_branch_base_for_tip(struct repository *r,
struct commit *tip,
struct commit **bases,
size_t bases_nr)
{
int best_index = -1;
struct commit *branch_point = NULL;
struct prio_queue queue = { compare_commits_by_gen_then_commit_date };
int found_missing_gen = 0;
if (!bases_nr)
return -1;
repo_parse_commit(r, tip);
if (commit_graph_generation(tip) == GENERATION_NUMBER_INFINITY)
found_missing_gen = 1;
/* Check for missing generation numbers. */
for (size_t i = 0; i < bases_nr; i++) {
struct commit *c = bases[i];
repo_parse_commit(r, c);
if (commit_graph_generation(c) == GENERATION_NUMBER_INFINITY)
found_missing_gen = 1;
}
if (found_missing_gen) {
struct commit **commits;
size_t commits_nr = bases_nr + 1;
CALLOC_ARRAY(commits, commits_nr);
COPY_ARRAY(commits, bases, bases_nr);
commits[bases_nr] = tip;
ensure_generations_valid(r, commits, commits_nr);
free(commits);
}
/* Initialize queue and slab now that generations are guaranteed. */
init_best_branch_base(&best_branch_base);
set_best(tip, -1);
prio_queue_put(&queue, tip);
for (size_t i = 0; i < bases_nr; i++) {
struct commit *c = bases[i];
int best = get_best(c);
/* Has this already been marked as best by another commit? */
if (best) {
if (best == -1) {
/* We agree at this position. Stop now. */
best_index = i + 1;
goto cleanup;
}
continue;
}
set_best(c, i + 1);
prio_queue_put(&queue, c);
}
while (queue.nr) {
struct commit *c = prio_queue_get(&queue);
int best_for_c = get_best(c);
int best_for_p, positive;
struct commit *parent;
/* Have we reached a known branch point? It's optimal. */
if (c == branch_point)
break;
repo_parse_commit(r, c);
if (!c->parents)
continue;
parent = c->parents->item;
repo_parse_commit(r, parent);
best_for_p = get_best(parent);
if (!best_for_p) {
/* 'parent' is new, so pass along best_for_c. */
set_best(parent, best_for_c);
prio_queue_put(&queue, parent);
continue;
}
if (best_for_p > 0 && best_for_c > 0) {
/* Collision among bases. Minimize. */
if (best_for_c < best_for_p)
set_best(parent, best_for_c);
continue;
}
/*
* At this point, we have reached a commit that is reachable
* from the tip, either from 'c' or from an earlier commit to
* have 'parent' as its first parent.
*
* Update 'best_index' to match the minimum of all base indices
* to reach 'parent'.
*/
/* Exactly one is positive due to initial conditions. */
positive = (best_for_c < 0) ? best_for_p : best_for_c;
if (best_index < 0 || positive < best_index)
best_index = positive;
/* No matter what, track that the parent is reachable from tip. */
set_best(parent, -1);
branch_point = parent;
}
cleanup:
clear_best_branch_base(&best_branch_base);
clear_prio_queue(&queue);
return best_index > 0 ? best_index - 1 : -1;
}
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