refs: plumb `exclude_patterns` argument throughout

The subsequent patch will want to access an optional `excluded_patterns`
array within `refs/packed-backend.c` that will cull out certain
references matching any of the given patterns on a best-effort basis.

To do so, the refs subsystem needs to be updated to pass this value
across a number of different locations.

Prepare for a future patch by introducing this plumbing now, passing
NULLs at top-level APIs in order to make that patch less noisy and more
easily readable.

Signed-off-by: Taylor Blau <me@ttaylorr.co>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

9 files changed, 42 insertions, 26 deletions

diff --git a/ls-refs.c b/ls-refs.c
index f385938b64..6f490b2d9c 100644
--- a/ls-refs.c
+++ b/ls-refs.c
@@ -193,7 +193,7 @@ int ls_refs(struct repository *r, struct packet_reader *request)
 		strvec_push(&data.prefixes, "");
 	refs_for_each_fullref_in_prefixes(get_main_ref_store(r),
 					  get_git_namespace(), data.prefixes.v,
-					  send_ref, &data);
+					  NULL, send_ref, &data);
 	packet_fflush(stdout);
 	strvec_clear(&data.prefixes);
 	strbuf_release(&data.buf);
diff --git a/ref-filter.c b/ref-filter.c
index ec9b79c918..c72d016bcc 100644
--- a/ref-filter.c
+++ b/ref-filter.c
@@ -2215,7 +2215,7 @@ static int for_each_fullref_in_pattern(struct ref_filter *filter,
 
 	return refs_for_each_fullref_in_prefixes(get_main_ref_store(the_repository),
 						 NULL, filter->name_patterns,
-						 cb, cb_data);
+						 NULL, cb, cb_data);
 }
 
 /*
diff --git a/refs.c b/refs.c
index b9b77d2eff..538bde644e 100644
--- a/refs.c
+++ b/refs.c
@@ -1526,7 +1526,9 @@ int head_ref(each_ref_fn fn, void *cb_data)
 
 struct ref_iterator *refs_ref_iterator_begin(
 		struct ref_store *refs,
-		const char *prefix, int trim,
+		const char *prefix,
+		const char **exclude_patterns,
+		int trim,
 		enum do_for_each_ref_flags flags)
 {
 	struct ref_iterator *iter;
@@ -1542,8 +1544,7 @@ struct ref_iterator *refs_ref_iterator_begin(
 		}
 	}
 
-	iter = refs->be->iterator_begin(refs, prefix, flags);
-
+	iter = refs->be->iterator_begin(refs, prefix, exclude_patterns, flags);
 	/*
 	 * `iterator_begin()` already takes care of prefix, but we
 	 * might need to do some trimming:
@@ -1577,7 +1578,7 @@ static int do_for_each_repo_ref(struct repository *r, const char *prefix,
 	if (!refs)
 		return 0;
 
-	iter = refs_ref_iterator_begin(refs, prefix, trim, flags);
+	iter = refs_ref_iterator_begin(refs, prefix, NULL, trim, flags);
 
 	return do_for_each_repo_ref_iterator(r, iter, fn, cb_data);
 }
@@ -1599,6 +1600,7 @@ static int do_for_each_ref_helper(struct repository *r,
 }
 
 static int do_for_each_ref(struct ref_store *refs, const char *prefix,
+			   const char **exclude_patterns,
 			   each_ref_fn fn, int trim,
 			   enum do_for_each_ref_flags flags, void *cb_data)
 {
@@ -1608,7 +1610,8 @@ static int do_for_each_ref(struct ref_store *refs, const char *prefix,
 	if (!refs)
 		return 0;
 
-	iter = refs_ref_iterator_begin(refs, prefix, trim, flags);
+	iter = refs_ref_iterator_begin(refs, prefix, exclude_patterns, trim,
+				       flags);
 
 	return do_for_each_repo_ref_iterator(the_repository, iter,
 					do_for_each_ref_helper, &hp);
@@ -1616,7 +1619,7 @@ static int do_for_each_ref(struct ref_store *refs, const char *prefix,
 
 int refs_for_each_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
 {
-	return do_for_each_ref(refs, "", fn, 0, 0, cb_data);
+	return do_for_each_ref(refs, "", NULL, fn, 0, 0, cb_data);
 }
 
 int for_each_ref(each_ref_fn fn, void *cb_data)
@@ -1627,7 +1630,7 @@ int for_each_ref(each_ref_fn fn, void *cb_data)
 int refs_for_each_ref_in(struct ref_store *refs, const char *prefix,
 			 each_ref_fn fn, void *cb_data)
 {
-	return do_for_each_ref(refs, prefix, fn, strlen(prefix), 0, cb_data);
+	return do_for_each_ref(refs, prefix, NULL, fn, strlen(prefix), 0, cb_data);
 }
 
 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
@@ -1638,13 +1641,14 @@ int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
 int for_each_fullref_in(const char *prefix, each_ref_fn fn, void *cb_data)
 {
 	return do_for_each_ref(get_main_ref_store(the_repository),
-			       prefix, fn, 0, 0, cb_data);
+			       prefix, NULL, fn, 0, 0, cb_data);
 }
 
 int refs_for_each_fullref_in(struct ref_store *refs, const char *prefix,
+			     const char **exclude_patterns,
 			     each_ref_fn fn, void *cb_data)
 {
-	return do_for_each_ref(refs, prefix, fn, 0, 0, cb_data);
+	return do_for_each_ref(refs, prefix, exclude_patterns, fn, 0, 0, cb_data);
 }
 
 int for_each_replace_ref(struct repository *r, each_repo_ref_fn fn, void *cb_data)
@@ -1661,14 +1665,14 @@ int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
 	int ret;
 	strbuf_addf(&buf, "%srefs/", get_git_namespace());
 	ret = do_for_each_ref(get_main_ref_store(the_repository),
-			      buf.buf, fn, 0, 0, cb_data);
+			      buf.buf, NULL, fn, 0, 0, cb_data);
 	strbuf_release(&buf);
 	return ret;
 }
 
 int refs_for_each_rawref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
 {
-	return do_for_each_ref(refs, "", fn, 0,
+	return do_for_each_ref(refs, "", NULL, fn, 0,
 			       DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
 }
 
@@ -1738,6 +1742,7 @@ static void find_longest_prefixes(struct string_list *out,
 int refs_for_each_fullref_in_prefixes(struct ref_store *ref_store,
 				      const char *namespace,
 				      const char **patterns,
+				      const char **exclude_patterns,
 				      each_ref_fn fn, void *cb_data)
 {
 	struct string_list prefixes = STRING_LIST_INIT_DUP;
@@ -1753,7 +1758,8 @@ int refs_for_each_fullref_in_prefixes(struct ref_store *ref_store,
 
 	for_each_string_list_item(prefix, &prefixes) {
 		strbuf_addstr(&buf, prefix->string);
-		ret = refs_for_each_fullref_in(ref_store, buf.buf, fn, cb_data);
+		ret = refs_for_each_fullref_in(ref_store, buf.buf,
+					       exclude_patterns, fn, cb_data);
 		if (ret)
 			break;
 		strbuf_setlen(&buf, namespace_len);
@@ -2408,7 +2414,7 @@ int refs_verify_refname_available(struct ref_store *refs,
 	strbuf_addstr(&dirname, refname + dirname.len);
 	strbuf_addch(&dirname, '/');
 
-	iter = refs_ref_iterator_begin(refs, dirname.buf, 0,
+	iter = refs_ref_iterator_begin(refs, dirname.buf, NULL, 0,
 				       DO_FOR_EACH_INCLUDE_BROKEN);
 	while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
 		if (skip &&
diff --git a/refs.h b/refs.h
index 123cfa4424..d672d636cf 100644
--- a/refs.h
+++ b/refs.h
@@ -338,6 +338,7 @@ int for_each_ref(each_ref_fn fn, void *cb_data);
 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data);
 
 int refs_for_each_fullref_in(struct ref_store *refs, const char *prefix,
+			     const char **exclude_patterns,
 			     each_ref_fn fn, void *cb_data);
 int for_each_fullref_in(const char *prefix, each_ref_fn fn, void *cb_data);
 
@@ -345,10 +346,15 @@ int for_each_fullref_in(const char *prefix, each_ref_fn fn, void *cb_data);
  * iterate all refs in "patterns" by partitioning patterns into disjoint sets
  * and iterating the longest-common prefix of each set.
  *
+ * references matching any pattern in "exclude_patterns" are omitted from the
+ * result set on a best-effort basis.
+ *
  * callers should be prepared to ignore references that they did not ask for.
  */
 int refs_for_each_fullref_in_prefixes(struct ref_store *refs,
-				      const char *namespace, const char **patterns,
+				      const char *namespace,
+				      const char **patterns,
+				      const char **exclude_patterns,
 				      each_ref_fn fn, void *cb_data);
 
 /**
diff --git a/refs/debug.c b/refs/debug.c
index 6f11e6de46..328f894177 100644
--- a/refs/debug.c
+++ b/refs/debug.c
@@ -229,11 +229,12 @@ static struct ref_iterator_vtable debug_ref_iterator_vtable = {
 
 static struct ref_iterator *
 debug_ref_iterator_begin(struct ref_store *ref_store, const char *prefix,
-			 unsigned int flags)
+			 const char **exclude_patterns, unsigned int flags)
 {
 	struct debug_ref_store *drefs = (struct debug_ref_store *)ref_store;
 	struct ref_iterator *res =
-		drefs->refs->be->iterator_begin(drefs->refs, prefix, flags);
+		drefs->refs->be->iterator_begin(drefs->refs, prefix,
+						exclude_patterns, flags);
 	struct debug_ref_iterator *diter = xcalloc(1, sizeof(*diter));
 	base_ref_iterator_init(&diter->base, &debug_ref_iterator_vtable, 1);
 	diter->iter = res;
diff --git a/refs/files-backend.c b/refs/files-backend.c
index bca7b851c5..3bc3c57c05 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -829,7 +829,8 @@ static struct ref_iterator_vtable files_ref_iterator_vtable = {
 
 static struct ref_iterator *files_ref_iterator_begin(
 		struct ref_store *ref_store,
-		const char *prefix, unsigned int flags)
+		const char *prefix, const char **exclude_patterns,
+		unsigned int flags)
 {
 	struct files_ref_store *refs;
 	struct ref_iterator *loose_iter, *packed_iter, *overlay_iter;
@@ -874,7 +875,7 @@ static struct ref_iterator *files_ref_iterator_begin(
 	 * the packed and loose references.
 	 */
 	packed_iter = refs_ref_iterator_begin(
-			refs->packed_ref_store, prefix, 0,
+			refs->packed_ref_store, prefix, exclude_patterns, 0,
 			DO_FOR_EACH_INCLUDE_BROKEN);
 
 	overlay_iter = overlay_ref_iterator_begin(loose_iter, packed_iter);
diff --git a/refs/packed-backend.c b/refs/packed-backend.c
index 5b412a133b..176bd3905b 100644
--- a/refs/packed-backend.c
+++ b/refs/packed-backend.c
@@ -924,7 +924,8 @@ static struct ref_iterator_vtable packed_ref_iterator_vtable = {
 
 static struct ref_iterator *packed_ref_iterator_begin(
 		struct ref_store *ref_store,
-		const char *prefix, unsigned int flags)
+		const char *prefix, const char **exclude_patterns,
+		unsigned int flags)
 {
 	struct packed_ref_store *refs;
 	struct snapshot *snapshot;
@@ -1149,7 +1150,7 @@ static int write_with_updates(struct packed_ref_store *refs,
 	 * list of refs is exhausted, set iter to NULL. When the list
 	 * of updates is exhausted, leave i set to updates->nr.
 	 */
-	iter = packed_ref_iterator_begin(&refs->base, "",
+	iter = packed_ref_iterator_begin(&refs->base, "", NULL,
 					 DO_FOR_EACH_INCLUDE_BROKEN);
 	if ((ok = ref_iterator_advance(iter)) != ITER_OK)
 		iter = NULL;
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index a85d113123..28a11b9d61 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -367,8 +367,8 @@ int is_empty_ref_iterator(struct ref_iterator *ref_iterator);
  */
 struct ref_iterator *refs_ref_iterator_begin(
 		struct ref_store *refs,
-		const char *prefix, int trim,
-		enum do_for_each_ref_flags flags);
+		const char *prefix, const char **exclude_patterns,
+		int trim, enum do_for_each_ref_flags flags);
 
 /*
  * A callback function used to instruct merge_ref_iterator how to
@@ -570,7 +570,8 @@ typedef int copy_ref_fn(struct ref_store *ref_store,
  */
 typedef struct ref_iterator *ref_iterator_begin_fn(
 		struct ref_store *ref_store,
-		const char *prefix, unsigned int flags);
+		const char *prefix, const char **exclude_patterns,
+		unsigned int flags);
 
 /* reflog functions */
 
diff --git a/revision.c b/revision.c
index b33cc1d106..89953592f9 100644
--- a/revision.c
+++ b/revision.c
@@ -2670,7 +2670,7 @@ static int for_each_bisect_ref(struct ref_store *refs, each_ref_fn fn,
 	struct strbuf bisect_refs = STRBUF_INIT;
 	int status;
 	strbuf_addf(&bisect_refs, "refs/bisect/%s", term);
-	status = refs_for_each_fullref_in(refs, bisect_refs.buf, fn, cb_data);
+	status = refs_for_each_fullref_in(refs, bisect_refs.buf, NULL, fn, cb_data);
 	strbuf_release(&bisect_refs);
 	return status;
 }