From: Jeff Hostetler <jeffhost@xxxxxxxxxxxxx>
Create a filter for traverse_commit_list_filtered() to omit the
blobs that would not be needed by a sparse checkout using the
given sparse-checkout spec.
This filter will be used in a future commit by rev-list and
pack-objects for partial/narrow clone/fetch.
A future enhancement should be able to also omit tree objects
not needed by such a sparse checkout, but that is not currently
supported.
Signed-off-by: Jeff Hostetler <jeffhost@xxxxxxxxxxxxx>
---
list-objects-filters.c | 179 +++++++++++++++++++++++++++++++++++++++++++++++++
list-objects-filters.h | 16 +++++
2 files changed, 195 insertions(+)
diff --git a/list-objects-filters.c b/list-objects-filters.c
index f04d70e..cacf645 100644
--- a/list-objects-filters.c
+++ b/list-objects-filters.c
@@ -180,3 +180,182 @@ void traverse_commit_list_omit_large_blobs(
oidset2_clear(&d.omits);
}
+
+/*
+ * A filter driven by a sparse-checkout specification to only
+ * include blobs that a sparse checkout would populate.
+ *
+ * The sparse-checkout spec is loaded from the blob with the
+ * given OID (rather than .git/info/sparse-checkout) because
+ * the repo may be bare.
+ */
+struct frame {
+ int defval;
+ int child_prov_omit : 1;
+};
+
+struct filter_use_sparse_data {
+ struct oidset2 omits;
+ struct exclude_list el;
+
+ size_t nr, alloc;
+ struct frame *array_frame;
+};
+
+static list_objects_filter_result filter_use_sparse(
+ list_objects_filter_type filter_type,
+ struct object *obj,
+ const char *pathname,
+ const char *filename,
+ void *filter_data_)
+{
+ struct filter_use_sparse_data *filter_data = filter_data_;
+ int64_t object_length = -1;
+ int val, dtype;
+ unsigned long s;
+ enum object_type t;
+ struct frame *frame;
+
+ switch (filter_type) {
+ default:
+ die("unkown filter_type");
+ return LOFR_ZERO;
+
+ case LOFT_BEGIN_TREE:
+ assert(obj->type == OBJ_TREE);
+ dtype = DT_DIR;
+ val = is_excluded_from_list(pathname, strlen(pathname),
+ filename, &dtype, &filter_data->el);
+ if (val < 0)
+ val = filter_data->array_frame[filter_data->nr].defval;
+
+ ALLOC_GROW(filter_data->array_frame, filter_data->nr + 1,
+ filter_data->alloc);
+ filter_data->nr++;
+ filter_data->array_frame[filter_data->nr].defval = val;
+ filter_data->array_frame[filter_data->nr].child_prov_omit = 0;
+
+ /*
+ * A directory with this tree OID may appear in multiple
+ * places in the tree. (Think of a directory move, with
+ * no other changes.) And with a different pathname, the
+ * is_excluded...() results for this directory and items
+ * contained within it may be different. So we cannot
+ * mark it SEEN (yet), since that will prevent process_tree()
+ * from revisiting this tree object with other pathnames.
+ *
+ * Only 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_REVISIT)
+ return LOFR_ZERO;
+ obj->flags |= FILTER_REVISIT;
+ return LOFR_SHOW;
+
+ case LOFT_END_TREE:
+ assert(obj->type == OBJ_TREE);
+ assert(filter_data->nr > 0);
+
+ frame = &filter_data->array_frame[filter_data->nr];
+ filter_data->nr--;
+
+ /*
+ * Tell our parent directory if any of our children were
+ * provisionally omitted.
+ */
+ filter_data->array_frame[filter_data->nr].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 LOFT_BLOB:
+ assert(obj->type == OBJ_BLOB);
+ assert((obj->flags & SEEN) == 0);
+
+ frame = &filter_data->array_frame[filter_data->nr];
+
+ /*
+ * If we previously provisionally omitted this blob because
+ * its pathname was not in the sparse-checkout AND this
+ * reference to the blob has the same pathname, we can avoid
+ * repeating the exclusion logic on this pathname and just
+ * continue to provisionally omit it.
+ */
+ if (obj->flags & FILTER_REVISIT) {
+ struct oidset2_entry *entry_prev;
+ entry_prev = oidset2_get(&filter_data->omits, &obj->oid);
+ if (entry_prev && !strcmp(pathname, entry_prev->pathname)) {
+ frame->child_prov_omit = 1;
+ return LOFR_ZERO;
+ }
+ }
+
+ dtype = DT_REG;
+ val = is_excluded_from_list(pathname, strlen(pathname),
+ filename, &dtype, &filter_data->el);
+ if (val < 0)
+ val = frame->defval;
+ if (val > 0)
+ return LOFR_MARK_SEEN | LOFR_SHOW;
+
+ t = sha1_object_info(obj->oid.hash, &s);
+ assert(t == OBJ_BLOB);
+ object_length = (int64_t)((uint64_t)(s));
+
+ /*
+ * Provisionally omit it. We've already established that
+ * this pathname is not in the sparse-checkout specification,
+ * 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.
+ *
+ * The pathname we associate with this omit is just the first
+ * one we saw for this blob. Other instances of this blob may
+ * have other pathnames and that is fine. We just use it for
+ * perf because most of the time, the blob will be in the same
+ * place as we walk the commits.
+ */
+ oidset2_insert(&filter_data->omits, &obj->oid, object_length,
+ pathname);
+ obj->flags |= FILTER_REVISIT;
+ frame->child_prov_omit = 1;
+ return LOFR_ZERO;
+ }
+}
+
+void traverse_commit_list_use_sparse(
+ struct rev_info *revs,
+ show_commit_fn show_commit,
+ show_object_fn show_object,
+ oidset2_foreach_cb print_omitted_object,
+ void *ctx_data,
+ struct object_id *oid)
+{
+ struct filter_use_sparse_data d;
+
+ memset(&d, 0, sizeof(d));
+ if (add_excludes_from_blob_to_list(oid, NULL, 0, &d.el) < 0)
+ die("filter_use_sparse could not load specification");
+ ALLOC_GROW(d.array_frame, d.nr + 1, d.alloc);
+ d.array_frame[d.nr].defval = 0; /* default to include */
+ d.array_frame[d.nr].child_prov_omit = 0;
+
+ traverse_commit_list_filtered(revs, show_commit, show_object, ctx_data,
+ filter_use_sparse, &d);
+
+ if (print_omitted_object)
+ oidset2_foreach(&d.omits, print_omitted_object, ctx_data);
+
+ oidset2_clear(&d.omits);
+}
diff --git a/list-objects-filters.h b/list-objects-filters.h
index 32b2833..52e507b 100644
--- a/list-objects-filters.h
+++ b/list-objects-filters.h
@@ -26,4 +26,20 @@ void traverse_commit_list_omit_large_blobs(
void *ctx_data,
int64_t large_byte_limit);
+/*
+ * A filter driven by a sparse-checkout specification to only
+ * include blobs that a sparse checkout would populate.
+ *
+ * The sparse-checkout spec is loaded from the blob with the
+ * given OID (rather than .git/info/sparse-checkout) because
+ * the repo may be bare.
+ */
+void traverse_commit_list_use_sparse(
+ struct rev_info *revs,
+ show_commit_fn show_commit,
+ show_object_fn show_object,
+ oidset2_foreach_cb print_omitted_object,
+ void *ctx_data,
+ struct object_id *oid);
+
#endif /* LIST_OBJECTS_FILTERS_H */
--
2.9.3
