Adding upstream version 1:2.39.2.upstream/1%2.39.2upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 831 insertions, 0 deletions

diff --git a/list-objects-filter.c b/list-objects-filter.c
new file mode 100644
index 0000000..b954354
--- /dev/null
+++ b/list-objects-filter.c
@@ -0,0 +1,831 @@
+#include "cache.h"
+#include "dir.h"
+#include "tag.h"
+#include "commit.h"
+#include "tree.h"
+#include "blob.h"
+#include "diff.h"
+#include "tree-walk.h"
+#include "revision.h"
+#include "list-objects.h"
+#include "list-objects-filter.h"
+#include "list-objects-filter-options.h"
+#include "oidmap.h"
+#include "oidset.h"
+#include "object-store.h"
+
+/* Remember to update object flag allocation in object.h */
+/*
+ * FILTER_SHOWN_BUT_REVISIT -- we set this bit on tree objects
+ * that have been shown, but should be revisited if they appear
+ * in the traversal (until we mark it SEEN).  This is a way to
+ * let us silently de-dup calls to show() in the caller.  This
+ * is subtly different from the "revision.h:SHOWN" and the
+ * "object-name.c:ONELINE_SEEN" bits.  And also different from
+ * the non-de-dup usage in pack-bitmap.c
+ */
+#define FILTER_SHOWN_BUT_REVISIT (1<<21)
+
+struct subfilter {
+	struct filter *filter;
+	struct oidset seen;
+	struct oidset omits;
+	struct object_id skip_tree;
+	unsigned is_skipping_tree : 1;
+};
+
+struct filter {
+	enum list_objects_filter_result (*filter_object_fn)(
+		struct repository *r,
+		enum list_objects_filter_situation filter_situation,
+		struct object *obj,
+		const char *pathname,
+		const char *filename,
+		struct oidset *omits,
+		void *filter_data);
+
+	/*
+	 * Optional. If this function is supplied and the filter needs
+	 * to collect omits, then this function is called once before
+	 * free_fn is called.
+	 *
+	 * This is required because the following two conditions hold:
+	 *
+	 *   a. A tree filter can add and remove objects as an object
+	 *      graph is traversed.
+	 *   b. A combine filter's omit set is the union of all its
+	 *      subfilters, which may include tree: filters.
+	 *
+	 * As such, the omits sets must be separate sets, and can only
+	 * be unioned after the traversal is completed.
+	 */
+	void (*finalize_omits_fn)(struct oidset *omits, void *filter_data);
+
+	void (*free_fn)(void *filter_data);
+
+	void *filter_data;
+
+	/* If non-NULL, the filter collects a list of the omitted OIDs here. */
+	struct oidset *omits;
+};
+
+static enum list_objects_filter_result filter_blobs_none(
+	struct repository *r,
+	enum list_objects_filter_situation filter_situation,
+	struct object *obj,
+	const char *pathname,
+	const char *filename,
+	struct oidset *omits,
+	void *filter_data_)
+{
+	switch (filter_situation) {
+	default:
+		BUG("unknown filter_situation: %d", filter_situation);
+
+	case LOFS_TAG:
+		assert(obj->type == OBJ_TAG);
+		/* always include all tag objects */
+		return LOFR_MARK_SEEN | LOFR_DO_SHOW;
+
+	case LOFS_COMMIT:
+		assert(obj->type == OBJ_COMMIT);
+		/* always include all commit objects */
+		return LOFR_MARK_SEEN | LOFR_DO_SHOW;
+
+	case LOFS_BEGIN_TREE:
+		assert(obj->type == OBJ_TREE);
+		/* always include all tree objects */
+		return LOFR_MARK_SEEN | LOFR_DO_SHOW;
+
+	case LOFS_END_TREE:
+		assert(obj->type == OBJ_TREE);
+		return LOFR_ZERO;
+
+	case LOFS_BLOB:
+		assert(obj->type == OBJ_BLOB);
+		assert((obj->flags & SEEN) == 0);
+
+		if (omits)
+			oidset_insert(omits, &obj->oid);
+		return LOFR_MARK_SEEN; /* but not LOFR_DO_SHOW (hard omit) */
+	}
+}
+
+static void filter_blobs_none__init(
+	struct list_objects_filter_options *filter_options,
+	struct filter *filter)
+{
+	filter->filter_object_fn = filter_blobs_none;
+	filter->free_fn = free;
+}
+
+/*
+ * A filter for list-objects to omit ALL trees and blobs from the traversal.
+ * Can OPTIONALLY collect a list of the omitted OIDs.
+ */
+struct filter_trees_depth_data {
+	/*
+	 * Maps trees to the minimum depth at which they were seen. It is not
+	 * necessary to re-traverse a tree at deeper or equal depths than it has
+	 * already been traversed.
+	 *
+	 * We can't use LOFR_MARK_SEEN for tree objects since this will prevent
+	 * it from being traversed at shallower depths.
+	 */
+	struct oidmap seen_at_depth;
+
+	unsigned long exclude_depth;
+	unsigned long current_depth;
+};
+
+struct seen_map_entry {
+	struct oidmap_entry base;
+	size_t depth;
+};
+
+/* Returns 1 if the oid was in the omits set before it was invoked. */
+static int filter_trees_update_omits(
+	struct object *obj,
+	struct oidset *omits,
+	int include_it)
+{
+	if (!omits)
+		return 0;
+
+	if (include_it)
+		return oidset_remove(omits, &obj->oid);
+	else
+		return oidset_insert(omits, &obj->oid);
+}
+
+static enum list_objects_filter_result filter_trees_depth(
+	struct repository *r,
+	enum list_objects_filter_situation filter_situation,
+	struct object *obj,
+	const char *pathname,
+	const char *filename,
+	struct oidset *omits,
+	void *filter_data_)
+{
+	struct filter_trees_depth_data *filter_data = filter_data_;
+	struct seen_map_entry *seen_info;
+	int include_it = filter_data->current_depth <
+		filter_data->exclude_depth;
+	int filter_res;
+	int already_seen;
+
+	/*
+	 * Note that we do not use _MARK_SEEN in order to allow re-traversal in
+	 * case we encounter a tree or blob again at a shallower depth.
+	 */
+
+	switch (filter_situation) {
+	default:
+		BUG("unknown filter_situation: %d", filter_situation);
+
+	case LOFS_TAG:
+		assert(obj->type == OBJ_TAG);
+		/* always include all tag objects */
+		return LOFR_MARK_SEEN | LOFR_DO_SHOW;
+
+	case LOFS_COMMIT:
+		assert(obj->type == OBJ_COMMIT);
+		/* always include all commit objects */
+		return LOFR_MARK_SEEN | LOFR_DO_SHOW;
+
+	case LOFS_END_TREE:
+		assert(obj->type == OBJ_TREE);
+		filter_data->current_depth--;
+		return LOFR_ZERO;
+
+	case LOFS_BLOB:
+		filter_trees_update_omits(obj, omits, include_it);
+		return include_it ? LOFR_MARK_SEEN | LOFR_DO_SHOW : LOFR_ZERO;
+
+	case LOFS_BEGIN_TREE:
+		seen_info = oidmap_get(
+			&filter_data->seen_at_depth, &obj->oid);
+		if (!seen_info) {
+			CALLOC_ARRAY(seen_info, 1);
+			oidcpy(&seen_info->base.oid, &obj->oid);
+			seen_info->depth = filter_data->current_depth;
+			oidmap_put(&filter_data->seen_at_depth, seen_info);
+			already_seen = 0;
+		} else {
+			already_seen =
+				filter_data->current_depth >= seen_info->depth;
+		}
+
+		if (already_seen) {
+			filter_res = LOFR_SKIP_TREE;
+		} else {
+			int been_omitted = filter_trees_update_omits(
+				obj, omits, include_it);
+			seen_info->depth = filter_data->current_depth;
+
+			if (include_it)
+				filter_res = LOFR_DO_SHOW;
+			else if (omits && !been_omitted)
+				/*
+				 * Must update omit information of children
+				 * recursively; they have not been omitted yet.
+				 */
+				filter_res = LOFR_ZERO;
+			else
+				filter_res = LOFR_SKIP_TREE;
+		}
+
+		filter_data->current_depth++;
+		return filter_res;
+	}
+}
+
+static void filter_trees_free(void *filter_data) {
+	struct filter_trees_depth_data *d = filter_data;
+	if (!d)
+		return;
+	oidmap_free(&d->seen_at_depth, 1);
+	free(d);
+}
+
+static void filter_trees_depth__init(
+	struct list_objects_filter_options *filter_options,
+	struct filter *filter)
+{
+	struct filter_trees_depth_data *d = xcalloc(1, sizeof(*d));
+	oidmap_init(&d->seen_at_depth, 0);
+	d->exclude_depth = filter_options->tree_exclude_depth;
+	d->current_depth = 0;
+
+	filter->filter_data = d;
+	filter->filter_object_fn = filter_trees_depth;
+	filter->free_fn = filter_trees_free;
+}
+
+/*
+ * A filter for list-objects to omit large blobs.
+ * And to OPTIONALLY collect a list of the omitted OIDs.
+ */
+struct filter_blobs_limit_data {
+	unsigned long max_bytes;
+};
+
+static enum list_objects_filter_result filter_blobs_limit(
+	struct repository *r,
+	enum list_objects_filter_situation filter_situation,
+	struct object *obj,
+	const char *pathname,
+	const char *filename,
+	struct oidset *omits,
+	void *filter_data_)
+{
+	struct filter_blobs_limit_data *filter_data = filter_data_;
+	unsigned long object_length;
+	enum object_type t;
+
+	switch (filter_situation) {
+	default:
+		BUG("unknown filter_situation: %d", filter_situation);
+
+	case LOFS_TAG:
+		assert(obj->type == OBJ_TAG);
+		/* always include all tag objects */
+		return LOFR_MARK_SEEN | LOFR_DO_SHOW;
+
+	case LOFS_COMMIT:
+		assert(obj->type == OBJ_COMMIT);
+		/* always include all commit objects */
+		return LOFR_MARK_SEEN | LOFR_DO_SHOW;
+
+	case LOFS_BEGIN_TREE:
+		assert(obj->type == OBJ_TREE);
+		/* always include all tree objects */
+		return LOFR_MARK_SEEN | LOFR_DO_SHOW;
+
+	case LOFS_END_TREE:
+		assert(obj->type == OBJ_TREE);
+		return LOFR_ZERO;
+
+	case LOFS_BLOB:
+		assert(obj->type == OBJ_BLOB);
+		assert((obj->flags & SEEN) == 0);
+
+		t = oid_object_info(r, &obj->oid, &object_length);
+		if (t != OBJ_BLOB) { /* probably OBJ_NONE */
+			/*
+			 * We DO NOT have the blob locally, so we cannot
+			 * apply the size filter criteria.  Be conservative
+			 * and force show it (and let the caller deal with
+			 * the ambiguity).
+			 */
+			goto include_it;
+		}
+
+		if (object_length < filter_data->max_bytes)
+			goto include_it;
+
+		if (omits)
+			oidset_insert(omits, &obj->oid);
+		return LOFR_MARK_SEEN; /* but not LOFR_DO_SHOW (hard omit) */
+	}
+
+include_it:
+	if (omits)
+		oidset_remove(omits, &obj->oid);
+	return LOFR_MARK_SEEN | LOFR_DO_SHOW;
+}
+
+static void filter_blobs_limit__init(
+	struct list_objects_filter_options *filter_options,
+	struct filter *filter)
+{
+	struct filter_blobs_limit_data *d = xcalloc(1, sizeof(*d));
+	d->max_bytes = filter_options->blob_limit_value;
+
+	filter->filter_data = d;
+	filter->filter_object_fn = filter_blobs_limit;
+	filter->free_fn = free;
+}
+
+/*
+ * A filter driven by a sparse-checkout specification to only
+ * include blobs that a sparse checkout would populate.
+ *
+ * The sparse-checkout spec can be loaded from a blob with the
+ * given OID or from a local pathname.  We allow an OID because
+ * the repo may be bare or we may be doing the filtering on the
+ * server.
+ */
+struct frame {
+	/*
+	 * default_match is the usual default include/exclude value that
+	 * should be inherited as we recurse into directories based
+	 * upon pattern matching of the directory itself or of a
+	 * containing directory.
+	 */
+	enum pattern_match_result default_match;
+
+	/*
+	 * 1 if the directory (recursively) contains any provisionally
+	 * omitted objects.
+	 *
+	 * 0 if everything (recursively) contained in this directory
+	 * has been explicitly included (SHOWN) in the result and
+	 * the directory may be short-cut later in the traversal.
+	 */
+	unsigned child_prov_omit : 1;
+};
+
+struct filter_sparse_data {
+	struct pattern_list pl;
+
+	size_t nr, alloc;
+	struct frame *array_frame;
+};
+
+static enum list_objects_filter_result filter_sparse(
+	struct repository *r,
+	enum list_objects_filter_situation filter_situation,
+	struct object *obj,
+	const char *pathname,
+	const char *filename,
+	struct oidset *omits,
+	void *filter_data_)
+{
+	struct filter_sparse_data *filter_data = filter_data_;
+	int dtype;
+	struct frame *frame;
+	enum pattern_match_result match;
+
+	switch (filter_situation) {
+	default:
+		BUG("unknown filter_situation: %d", filter_situation);
+
+	case LOFS_TAG:
+		assert(obj->type == OBJ_TAG);
+		/* always include all tag objects */
+		return LOFR_MARK_SEEN | LOFR_DO_SHOW;
+
+	case LOFS_COMMIT:
+		assert(obj->type == OBJ_COMMIT);
+		/* always include all commit objects */
+		return LOFR_MARK_SEEN | LOFR_DO_SHOW;
+
+	case LOFS_BEGIN_TREE:
+		assert(obj->type == OBJ_TREE);
+		dtype = DT_DIR;
+		match = path_matches_pattern_list(pathname, strlen(pathname),
+						  filename, &dtype, &filter_data->pl,
+						  r->index);
+		if (match == UNDECIDED)
+			match = filter_data->array_frame[filter_data->nr - 1].default_match;
+
+		ALLOC_GROW(filter_data->array_frame, filter_data->nr + 1,
+			   filter_data->alloc);
+		filter_data->array_frame[filter_data->nr].default_match = match;
+		filter_data->array_frame[filter_data->nr].child_prov_omit = 0;
+		filter_data->nr++;
+
+		/*
+		 * A directory with this tree OID may appear in multiple
+		 * places in the tree. (Think of a directory move or copy,
+		 * with no other changes, so the OID is the same, but the
+		 * full pathnames of objects within this directory are new
+		 * and may match is_excluded() patterns differently.)
+		 * So we cannot mark this directory as SEEN (yet), since
+		 * that will prevent process_tree() from revisiting this
+		 * tree object with other pathname prefixes.
+		 *
+		 * Only _DO_SHOW the tree object the first time we visit
+		 * this tree object.
+		 *
+		 * We always show all tree objects.  A future optimization
+		 * may want to attempt to narrow this.
+		 */
+		if (obj->flags & FILTER_SHOWN_BUT_REVISIT)
+			return LOFR_ZERO;
+		obj->flags |= FILTER_SHOWN_BUT_REVISIT;
+		return LOFR_DO_SHOW;
+
+	case LOFS_END_TREE:
+		assert(obj->type == OBJ_TREE);
+		assert(filter_data->nr > 1);
+
+		frame = &filter_data->array_frame[--filter_data->nr];
+
+		/*
+		 * Tell our parent directory if any of our children were
+		 * provisionally omitted.
+		 */
+		filter_data->array_frame[filter_data->nr - 1].child_prov_omit |=
+			frame->child_prov_omit;
+
+		/*
+		 * If there are NO provisionally omitted child objects (ALL child
+		 * objects in this folder were INCLUDED), then we can mark the
+		 * folder as SEEN (so we will not have to revisit it again).
+		 */
+		if (!frame->child_prov_omit)
+			return LOFR_MARK_SEEN;
+		return LOFR_ZERO;
+
+	case LOFS_BLOB:
+		assert(obj->type == OBJ_BLOB);
+		assert((obj->flags & SEEN) == 0);
+
+		frame = &filter_data->array_frame[filter_data->nr - 1];
+
+		dtype = DT_REG;
+		match = path_matches_pattern_list(pathname, strlen(pathname),
+					    filename, &dtype, &filter_data->pl,
+					    r->index);
+		if (match == UNDECIDED)
+			match = frame->default_match;
+		if (match == MATCHED) {
+			if (omits)
+				oidset_remove(omits, &obj->oid);
+			return LOFR_MARK_SEEN | LOFR_DO_SHOW;
+		}
+
+		/*
+		 * Provisionally omit it.  We've already established that
+		 * this pathname is not in the sparse-checkout specification
+		 * with the CURRENT pathname, so we *WANT* to omit this blob.
+		 *
+		 * However, a pathname elsewhere in the tree may also
+		 * reference this same blob, so we cannot reject it yet.
+		 * Leave the LOFR_ bits unset so that if the blob appears
+		 * again in the traversal, we will be asked again.
+		 */
+		if (omits)
+			oidset_insert(omits, &obj->oid);
+
+		/*
+		 * Remember that at least 1 blob in this tree was
+		 * provisionally omitted.  This prevents us from short
+		 * cutting the tree in future iterations.
+		 */
+		frame->child_prov_omit = 1;
+		return LOFR_ZERO;
+	}
+}
+
+
+static void filter_sparse_free(void *filter_data)
+{
+	struct filter_sparse_data *d = filter_data;
+	free(d->array_frame);
+	free(d);
+}
+
+static void filter_sparse_oid__init(
+	struct list_objects_filter_options *filter_options,
+	struct filter *filter)
+{
+	struct filter_sparse_data *d = xcalloc(1, sizeof(*d));
+	struct object_context oc;
+	struct object_id sparse_oid;
+
+	if (get_oid_with_context(the_repository,
+				 filter_options->sparse_oid_name,
+				 GET_OID_BLOB, &sparse_oid, &oc))
+		die(_("unable to access sparse blob in '%s'"),
+		    filter_options->sparse_oid_name);
+	if (add_patterns_from_blob_to_list(&sparse_oid, "", 0, &d->pl) < 0)
+		die(_("unable to parse sparse filter data in %s"),
+		    oid_to_hex(&sparse_oid));
+
+	ALLOC_GROW(d->array_frame, d->nr + 1, d->alloc);
+	d->array_frame[d->nr].default_match = 0; /* default to include */
+	d->array_frame[d->nr].child_prov_omit = 0;
+	d->nr++;
+
+	filter->filter_data = d;
+	filter->filter_object_fn = filter_sparse;
+	filter->free_fn = filter_sparse_free;
+}
+
+/*
+ * A filter for list-objects to omit large blobs.
+ * And to OPTIONALLY collect a list of the omitted OIDs.
+ */
+struct filter_object_type_data {
+	enum object_type object_type;
+};
+
+static enum list_objects_filter_result filter_object_type(
+	struct repository *r,
+	enum list_objects_filter_situation filter_situation,
+	struct object *obj,
+	const char *pathname,
+	const char *filename,
+	struct oidset *omits,
+	void *filter_data_)
+{
+	struct filter_object_type_data *filter_data = filter_data_;
+
+	switch (filter_situation) {
+	default:
+		BUG("unknown filter_situation: %d", filter_situation);
+
+	case LOFS_TAG:
+		assert(obj->type == OBJ_TAG);
+		if (filter_data->object_type == OBJ_TAG)
+			return LOFR_MARK_SEEN | LOFR_DO_SHOW;
+		return LOFR_MARK_SEEN;
+
+	case LOFS_COMMIT:
+		assert(obj->type == OBJ_COMMIT);
+		if (filter_data->object_type == OBJ_COMMIT)
+			return LOFR_MARK_SEEN | LOFR_DO_SHOW;
+		return LOFR_MARK_SEEN;
+
+	case LOFS_BEGIN_TREE:
+		assert(obj->type == OBJ_TREE);
+
+		/*
+		 * If we only want to show commits or tags, then there is no
+		 * need to walk down trees.
+		 */
+		if (filter_data->object_type == OBJ_COMMIT ||
+		    filter_data->object_type == OBJ_TAG)
+			return LOFR_SKIP_TREE;
+
+		if (filter_data->object_type == OBJ_TREE)
+			return LOFR_MARK_SEEN | LOFR_DO_SHOW;
+
+		return LOFR_MARK_SEEN;
+
+	case LOFS_BLOB:
+		assert(obj->type == OBJ_BLOB);
+
+		if (filter_data->object_type == OBJ_BLOB)
+			return LOFR_MARK_SEEN | LOFR_DO_SHOW;
+		return LOFR_MARK_SEEN;
+
+	case LOFS_END_TREE:
+		return LOFR_ZERO;
+	}
+}
+
+static void filter_object_type__init(
+	struct list_objects_filter_options *filter_options,
+	struct filter *filter)
+{
+	struct filter_object_type_data *d = xcalloc(1, sizeof(*d));
+	d->object_type = filter_options->object_type;
+
+	filter->filter_data = d;
+	filter->filter_object_fn = filter_object_type;
+	filter->free_fn = free;
+}
+
+/* A filter which only shows objects shown by all sub-filters. */
+struct combine_filter_data {
+	struct subfilter *sub;
+	size_t nr;
+};
+
+static enum list_objects_filter_result process_subfilter(
+	struct repository *r,
+	enum list_objects_filter_situation filter_situation,
+	struct object *obj,
+	const char *pathname,
+	const char *filename,
+	struct subfilter *sub)
+{
+	enum list_objects_filter_result result;
+
+	/*
+	 * Check and update is_skipping_tree before oidset_contains so
+	 * that is_skipping_tree gets unset even when the object is
+	 * marked as seen.  As of this writing, no filter uses
+	 * LOFR_MARK_SEEN on trees that also uses LOFR_SKIP_TREE, so the
+	 * ordering is only theoretically important. Be cautious if you
+	 * change the order of the below checks and more filters have
+	 * been added!
+	 */
+	if (sub->is_skipping_tree) {
+		if (filter_situation == LOFS_END_TREE &&
+		    oideq(&obj->oid, &sub->skip_tree))
+			sub->is_skipping_tree = 0;
+		else
+			return LOFR_ZERO;
+	}
+	if (oidset_contains(&sub->seen, &obj->oid))
+		return LOFR_ZERO;
+
+	result = list_objects_filter__filter_object(
+		r, filter_situation, obj, pathname, filename, sub->filter);
+
+	if (result & LOFR_MARK_SEEN)
+		oidset_insert(&sub->seen, &obj->oid);
+
+	if (result & LOFR_SKIP_TREE) {
+		sub->is_skipping_tree = 1;
+		sub->skip_tree = obj->oid;
+	}
+
+	return result;
+}
+
+static enum list_objects_filter_result filter_combine(
+	struct repository *r,
+	enum list_objects_filter_situation filter_situation,
+	struct object *obj,
+	const char *pathname,
+	const char *filename,
+	struct oidset *omits,
+	void *filter_data)
+{
+	struct combine_filter_data *d = filter_data;
+	enum list_objects_filter_result combined_result =
+		LOFR_DO_SHOW | LOFR_MARK_SEEN | LOFR_SKIP_TREE;
+	size_t sub;
+
+	for (sub = 0; sub < d->nr; sub++) {
+		enum list_objects_filter_result sub_result = process_subfilter(
+			r, filter_situation, obj, pathname, filename,
+			&d->sub[sub]);
+		if (!(sub_result & LOFR_DO_SHOW))
+			combined_result &= ~LOFR_DO_SHOW;
+		if (!(sub_result & LOFR_MARK_SEEN))
+			combined_result &= ~LOFR_MARK_SEEN;
+		if (!d->sub[sub].is_skipping_tree)
+			combined_result &= ~LOFR_SKIP_TREE;
+	}
+
+	return combined_result;
+}
+
+static void filter_combine__free(void *filter_data)
+{
+	struct combine_filter_data *d = filter_data;
+	size_t sub;
+	for (sub = 0; sub < d->nr; sub++) {
+		list_objects_filter__free(d->sub[sub].filter);
+		oidset_clear(&d->sub[sub].seen);
+		if (d->sub[sub].omits.set.size)
+			BUG("expected oidset to be cleared already");
+	}
+	free(d->sub);
+	free(d);
+}
+
+static void add_all(struct oidset *dest, struct oidset *src) {
+	struct oidset_iter iter;
+	struct object_id *src_oid;
+
+	oidset_iter_init(src, &iter);
+	while ((src_oid = oidset_iter_next(&iter)) != NULL)
+		oidset_insert(dest, src_oid);
+}
+
+static void filter_combine__finalize_omits(
+	struct oidset *omits,
+	void *filter_data)
+{
+	struct combine_filter_data *d = filter_data;
+	size_t sub;
+
+	for (sub = 0; sub < d->nr; sub++) {
+		add_all(omits, &d->sub[sub].omits);
+		oidset_clear(&d->sub[sub].omits);
+	}
+}
+
+static void filter_combine__init(
+	struct list_objects_filter_options *filter_options,
+	struct filter* filter)
+{
+	struct combine_filter_data *d = xcalloc(1, sizeof(*d));
+	size_t sub;
+
+	d->nr = filter_options->sub_nr;
+	CALLOC_ARRAY(d->sub, d->nr);
+	for (sub = 0; sub < d->nr; sub++)
+		d->sub[sub].filter = list_objects_filter__init(
+			filter->omits ? &d->sub[sub].omits : NULL,
+			&filter_options->sub[sub]);
+
+	filter->filter_data = d;
+	filter->filter_object_fn = filter_combine;
+	filter->free_fn = filter_combine__free;
+	filter->finalize_omits_fn = filter_combine__finalize_omits;
+}
+
+typedef void (*filter_init_fn)(
+	struct list_objects_filter_options *filter_options,
+	struct filter *filter);
+
+/*
+ * Must match "enum list_objects_filter_choice".
+ */
+static filter_init_fn s_filters[] = {
+	NULL,
+	filter_blobs_none__init,
+	filter_blobs_limit__init,
+	filter_trees_depth__init,
+	filter_sparse_oid__init,
+	filter_object_type__init,
+	filter_combine__init,
+};
+
+struct filter *list_objects_filter__init(
+	struct oidset *omitted,
+	struct list_objects_filter_options *filter_options)
+{
+	struct filter *filter;
+	filter_init_fn init_fn;
+
+	assert((sizeof(s_filters) / sizeof(s_filters[0])) == LOFC__COUNT);
+
+	if (!filter_options)
+		return NULL;
+
+	if (filter_options->choice >= LOFC__COUNT)
+		BUG("invalid list-objects filter choice: %d",
+		    filter_options->choice);
+
+	init_fn = s_filters[filter_options->choice];
+	if (!init_fn)
+		return NULL;
+
+	CALLOC_ARRAY(filter, 1);
+	filter->omits = omitted;
+	init_fn(filter_options, filter);
+	return filter;
+}
+
+enum list_objects_filter_result list_objects_filter__filter_object(
+	struct repository *r,
+	enum list_objects_filter_situation filter_situation,
+	struct object *obj,
+	const char *pathname,
+	const char *filename,
+	struct filter *filter)
+{
+	if (filter && (obj->flags & NOT_USER_GIVEN))
+		return filter->filter_object_fn(r, filter_situation, obj,
+						pathname, filename,
+						filter->omits,
+						filter->filter_data);
+	/*
+	 * No filter is active or user gave object explicitly. In this case,
+	 * always show the object (except when LOFS_END_TREE, since this tree
+	 * had already been shown when LOFS_BEGIN_TREE).
+	 */
+	if (filter_situation == LOFS_END_TREE)
+		return 0;
+	return LOFR_MARK_SEEN | LOFR_DO_SHOW;
+}
+
+void list_objects_filter__free(struct filter *filter)
+{
+	if (!filter)
+		return;
+	if (filter->finalize_omits_fn && filter->omits)
+		filter->finalize_omits_fn(filter->omits, filter->filter_data);
+	filter->free_fn(filter->filter_data);
+	free(filter);
+}