list-objects: support for skipping tree traversal

The tree:0 filter does not need to traverse the trees that it has
filtered out, so optimize list-objects and list-objects-filter to skip
traversing the trees entirely. Before this patch, we iterated over all
children of the tree, and did nothing for all of them, which was
wasteful.

Signed-off-by: Matthew DeVore <matvore@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Matthew DeVore 2018-10-17 17:39:15 -07:00 committed by Junio C Hamano
parent d9e6d0942b
commit 8b10a206f0
4 changed files with 32 additions and 3 deletions

View File

@ -102,9 +102,16 @@ static enum list_objects_filter_result filter_trees_none(
case LOFS_BEGIN_TREE:
case LOFS_BLOB:
if (filter_data->omits)
if (filter_data->omits) {
oidset_insert(filter_data->omits, &obj->oid);
return LOFR_MARK_SEEN; /* but not LOFR_DO_SHOW (hard omit) */
/* _MARK_SEEN but not _DO_SHOW (hard omit) */
return LOFR_MARK_SEEN;
} else {
/*
* Not collecting omits so no need to to traverse tree.
*/
return LOFR_SKIP_TREE | LOFR_MARK_SEEN;
}
case LOFS_END_TREE:
assert(obj->type == OBJ_TREE);

View File

@ -20,6 +20,11 @@
* In general, objects should only be shown once, but
* this result DOES NOT imply that we mark it SEEN.
*
* _SKIP_TREE : Used in LOFS_BEGIN_TREE situation - indicates that
* the tree's children should not be iterated over. This
* is used as an optimization when all children will
* definitely be ignored.
*
* Most of the time, you want the combination (_MARK_SEEN | _DO_SHOW)
* but they can be used independently, such as when sparse-checkout
* pattern matching is being applied.
@ -41,6 +46,7 @@ enum list_objects_filter_result {
LOFR_ZERO = 0,
LOFR_MARK_SEEN = 1<<0,
LOFR_DO_SHOW = 1<<1,
LOFR_SKIP_TREE = 1<<2,
};
enum list_objects_filter_situation {

View File

@ -11,6 +11,7 @@
#include "list-objects-filter-options.h"
#include "packfile.h"
#include "object-store.h"
#include "trace.h"
struct traversal_context {
struct rev_info *revs;
@ -184,7 +185,9 @@ static void process_tree(struct traversal_context *ctx,
if (base->len)
strbuf_addch(base, '/');
if (!failed_parse)
if (r & LOFR_SKIP_TREE)
trace_printf("Skipping contents of tree %s...\n", base->buf);
else if (!failed_parse)
process_tree_contents(ctx, tree, base);
if ((obj->flags & NOT_USER_GIVEN) && ctx->filter_fn) {

View File

@ -245,6 +245,19 @@ test_expect_success 'verify tree:0 includes trees in "filtered" output' '
test_cmp expected filtered_types
'
# Make sure tree:0 does not iterate through any trees.
test_expect_success 'filter a GIANT tree through tree:0' '
GIT_TRACE=1 git -C r3 rev-list \
--objects --filter=tree:0 HEAD 2>filter_trace &&
grep "Skipping contents of tree [.][.][.]" filter_trace >actual &&
# One line for each commit traversed.
test_line_count = 2 actual &&
# Make sure no other trees were considered besides the root.
! grep "Skipping contents of tree [^.]" filter_trace
'
# Delete some loose objects and use rev-list, but WITHOUT any filtering.
# This models previously omitted objects that we did not receive.