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git-rev-list libification: rev-list walking
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This actually moves the "meat" of the revision walking from rev-list.c
to the new library code in revision.h. It introduces the new functions

	void prepare_revision_walk(struct rev_info *revs);
	struct commit *get_revision(struct rev_info *revs);

to prepare and then walk the revisions that we have.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
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Linus Torvalds authored and Junio C Hamano committed Feb 28, 2006
1 parent d9a8368 commit a4a88b2
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Showing 3 changed files with 266 additions and 251 deletions.
264 changes: 16 additions & 248 deletions rev-list.c
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Original file line number Diff line number Diff line change
Expand Up @@ -8,11 +8,10 @@
#include "diff.h"
#include "revision.h"

/* bits #0 and #1 in revision.h */
/* bits #0-2 in revision.h */

#define COUNTED (1u << 2)
#define SHOWN (1u << 3)
#define TREECHANGE (1u << 4)
#define COUNTED (1u << 3)
#define SHOWN (1u << 4)
#define TMP_MARK (1u << 5) /* for isolated cases; clean after use */

static const char rev_list_usage[] =
Expand Down Expand Up @@ -213,17 +212,17 @@ static struct object_list **process_tree(struct tree *tree,
return p;
}

static void show_commit_list(struct commit_list *list)
static void show_commit_list(struct rev_info *revs)
{
struct commit *commit;
struct object_list *objects = NULL, **p = &objects, *pending;
while (list) {
struct commit *commit = pop_most_recent_commit(&list, SEEN);

while ((commit = get_revision(revs)) != NULL) {
p = process_tree(commit->tree, p, NULL, "");
if (process_commit(commit) == STOP)
break;
}
for (pending = revs.pending_objects; pending; pending = pending->next) {
for (pending = revs->pending_objects; pending; pending = pending->next) {
struct object *obj = pending->item;
const char *name = pending->name;
if (obj->flags & (UNINTERESTING | SEEN))
Expand Down Expand Up @@ -259,19 +258,6 @@ static void show_commit_list(struct commit_list *list)
}
}

static int everybody_uninteresting(struct commit_list *orig)
{
struct commit_list *list = orig;
while (list) {
struct commit *commit = list->item;
list = list->next;
if (commit->object.flags & UNINTERESTING)
continue;
return 0;
}
return 1;
}

/*
* This is a truly stupid algorithm, but it's only
* used for bisection, and we just don't care enough.
Expand Down Expand Up @@ -379,224 +365,12 @@ static void mark_edges_uninteresting(struct commit_list *list)
}
}

#define TREE_SAME 0
#define TREE_NEW 1
#define TREE_DIFFERENT 2
static int tree_difference = TREE_SAME;

static void file_add_remove(struct diff_options *options,
int addremove, unsigned mode,
const unsigned char *sha1,
const char *base, const char *path)
{
int diff = TREE_DIFFERENT;

/*
* Is it an add of a new file? It means that
* the old tree didn't have it at all, so we
* will turn "TREE_SAME" -> "TREE_NEW", but
* leave any "TREE_DIFFERENT" alone (and if
* it already was "TREE_NEW", we'll keep it
* "TREE_NEW" of course).
*/
if (addremove == '+') {
diff = tree_difference;
if (diff != TREE_SAME)
return;
diff = TREE_NEW;
}
tree_difference = diff;
}

static void file_change(struct diff_options *options,
unsigned old_mode, unsigned new_mode,
const unsigned char *old_sha1,
const unsigned char *new_sha1,
const char *base, const char *path)
{
tree_difference = TREE_DIFFERENT;
}

static struct diff_options diff_opt = {
.recursive = 1,
.add_remove = file_add_remove,
.change = file_change,
};

static int compare_tree(struct tree *t1, struct tree *t2)
{
if (!t1)
return TREE_NEW;
if (!t2)
return TREE_DIFFERENT;
tree_difference = TREE_SAME;
if (diff_tree_sha1(t1->object.sha1, t2->object.sha1, "", &diff_opt) < 0)
return TREE_DIFFERENT;
return tree_difference;
}

static int same_tree_as_empty(struct tree *t1)
{
int retval;
void *tree;
struct tree_desc empty, real;

if (!t1)
return 0;

tree = read_object_with_reference(t1->object.sha1, "tree", &real.size, NULL);
if (!tree)
return 0;
real.buf = tree;

empty.buf = "";
empty.size = 0;

tree_difference = 0;
retval = diff_tree(&empty, &real, "", &diff_opt);
free(tree);

return retval >= 0 && !tree_difference;
}

static void try_to_simplify_commit(struct commit *commit)
{
struct commit_list **pp, *parent;

if (!commit->tree)
return;

if (!commit->parents) {
if (!same_tree_as_empty(commit->tree))
commit->object.flags |= TREECHANGE;
return;
}

pp = &commit->parents;
while ((parent = *pp) != NULL) {
struct commit *p = parent->item;

if (p->object.flags & UNINTERESTING) {
pp = &parent->next;
continue;
}

parse_commit(p);
switch (compare_tree(p->tree, commit->tree)) {
case TREE_SAME:
parent->next = NULL;
commit->parents = parent;
return;

case TREE_NEW:
if (revs.remove_empty_trees && same_tree_as_empty(p->tree)) {
*pp = parent->next;
continue;
}
/* fallthrough */
case TREE_DIFFERENT:
pp = &parent->next;
continue;
}
die("bad tree compare for commit %s", sha1_to_hex(commit->object.sha1));
}
commit->object.flags |= TREECHANGE;
}

static void add_parents_to_list(struct commit *commit, struct commit_list **list)
{
struct commit_list *parent = commit->parents;

/*
* If the commit is uninteresting, don't try to
* prune parents - we want the maximal uninteresting
* set.
*
* Normally we haven't parsed the parent
* yet, so we won't have a parent of a parent
* here. However, it may turn out that we've
* reached this commit some other way (where it
* wasn't uninteresting), in which case we need
* to mark its parents recursively too..
*/
if (commit->object.flags & UNINTERESTING) {
while (parent) {
struct commit *p = parent->item;
parent = parent->next;
parse_commit(p);
p->object.flags |= UNINTERESTING;
if (p->parents)
mark_parents_uninteresting(p);
if (p->object.flags & SEEN)
continue;
p->object.flags |= SEEN;
insert_by_date(p, list);
}
return;
}

/*
* Ok, the commit wasn't uninteresting. Try to
* simplify the commit history and find the parent
* that has no differences in the path set if one exists.
*/
if (revs.paths)
try_to_simplify_commit(commit);

parent = commit->parents;
while (parent) {
struct commit *p = parent->item;

parent = parent->next;

parse_commit(p);
if (p->object.flags & SEEN)
continue;
p->object.flags |= SEEN;
insert_by_date(p, list);
}
}

static struct commit_list *limit_list(struct commit_list *list)
{
struct commit_list *newlist = NULL;
struct commit_list **p = &newlist;
while (list) {
struct commit_list *entry = list;
struct commit *commit = list->item;
struct object *obj = &commit->object;

list = list->next;
free(entry);

if (revs.max_age != -1 && (commit->date < revs.max_age))
obj->flags |= UNINTERESTING;
if (revs.unpacked && has_sha1_pack(obj->sha1))
obj->flags |= UNINTERESTING;
add_parents_to_list(commit, &list);
if (obj->flags & UNINTERESTING) {
mark_parents_uninteresting(commit);
if (everybody_uninteresting(list))
break;
continue;
}
if (revs.min_age != -1 && (commit->date > revs.min_age))
continue;
p = &commit_list_insert(commit, p)->next;
}
if (revs.tree_objects)
mark_edges_uninteresting(newlist);
if (bisect_list)
newlist = find_bisection(newlist);
return newlist;
}

int main(int argc, const char **argv)
{
struct commit_list *list;
int i;

argc = setup_revisions(argc, argv, &revs);
argc = setup_revisions(argc, argv, &revs, NULL);

for (i = 1 ; i < argc; i++) {
const char *arg = argv[i];
Expand Down Expand Up @@ -672,24 +446,18 @@ int main(int argc, const char **argv)
(!(revs.tag_objects||revs.tree_objects||revs.blob_objects) && !revs.pending_objects))
usage(rev_list_usage);

if (revs.paths)
diff_tree_setup_paths(revs.paths);
prepare_revision_walk(&revs);
if (revs.tree_objects)
mark_edges_uninteresting(revs.commits);

if (bisect_list)
revs.commits = find_bisection(revs.commits);

save_commit_buffer = verbose_header;
track_object_refs = 0;

if (!merge_order) {
sort_by_date(&list);
if (list && !revs.limited && revs.max_count == 1 &&
!revs.tag_objects && !revs.tree_objects && !revs.blob_objects) {
show_commit(list->item);
return 0;
}
if (revs.limited)
list = limit_list(list);
if (revs.topo_order)
sort_in_topological_order(&list, revs.lifo);
show_commit_list(list);
if (!merge_order) {
show_commit_list(&revs);
} else {
#ifndef NO_OPENSSL
if (sort_list_in_merge_order(list, &process_commit)) {
Expand Down
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