revision: introduce struct to handle exclusions

The functions that handle exclusion of refs work on a single string
list. We're about to add a second mechanism for excluding refs though,
and it makes sense to reuse much of the same architecture for both kinds
of exclusion.

Introduce a new `struct ref_exclusions` that encapsulates all the logic
related to excluding refs and move the `struct string_list` that holds
all wildmatch patterns of excluded refs into it. Rename functions that
operate on this struct to match its name.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Taylor Blau <me@ttaylorr.com>

3 files changed, 47 insertions, 36 deletions

diff --git a/builtin/rev-parse.c b/builtin/rev-parse.c
index 8f61050bde..7fa5b6991b 100644
--- a/builtin/rev-parse.c
+++ b/builtin/rev-parse.c
@@ -39,7 +39,7 @@ static int abbrev_ref_strict;
 static int output_sq;
 
 static int stuck_long;
-static struct string_list *ref_excludes;
+static struct ref_exclusions ref_excludes = REF_EXCLUSIONS_INIT;
 
 /*
  * Some arguments are relevant "revision" arguments,
@@ -198,7 +198,7 @@ static int show_default(void)
 static int show_reference(const char *refname, const struct object_id *oid,
 			  int flag UNUSED, void *cb_data UNUSED)
 {
-	if (ref_excluded(ref_excludes, refname))
+	if (ref_excluded(&ref_excludes, refname))
 		return 0;
 	show_rev(NORMAL, oid, refname);
 	return 0;
@@ -585,7 +585,7 @@ static void handle_ref_opt(const char *pattern, const char *prefix)
 		for_each_glob_ref_in(show_reference, pattern, prefix, NULL);
 	else
 		for_each_ref_in(prefix, show_reference, NULL);
-	clear_ref_exclusion(&ref_excludes);
+	clear_ref_exclusions(&ref_excludes);
 }
 
 enum format_type {
@@ -863,7 +863,7 @@ int cmd_rev_parse(int argc, const char **argv, const char *prefix)
 			}
 			if (!strcmp(arg, "--all")) {
 				for_each_ref(show_reference, NULL);
-				clear_ref_exclusion(&ref_excludes);
+				clear_ref_exclusions(&ref_excludes);
 				continue;
 			}
 			if (skip_prefix(arg, "--disambiguate=", &arg)) {
diff --git a/revision.c b/revision.c
index be755670e2..fe3ec98f46 100644
--- a/revision.c
+++ b/revision.c
@@ -1517,35 +1517,30 @@ static void add_rev_cmdline_list(struct rev_info *revs,
 	}
 }
 
-int ref_excluded(struct string_list *ref_excludes, const char *path)
+int ref_excluded(const struct ref_exclusions *exclusions, const char *path)
 {
 	struct string_list_item *item;
-
-	if (!ref_excludes)
-		return 0;
-	for_each_string_list_item(item, ref_excludes) {
+	for_each_string_list_item(item, &exclusions->excluded_refs) {
 		if (!wildmatch(item->string, path, 0))
 			return 1;
 	}
 	return 0;
 }
 
-void clear_ref_exclusion(struct string_list **ref_excludes_p)
+void init_ref_exclusions(struct ref_exclusions *exclusions)
 {
-	if (*ref_excludes_p) {
-		string_list_clear(*ref_excludes_p, 0);
-		free(*ref_excludes_p);
-	}
-	*ref_excludes_p = NULL;
+	struct ref_exclusions blank = REF_EXCLUSIONS_INIT;
+	memcpy(exclusions, &blank, sizeof(*exclusions));
 }
 
-void add_ref_exclusion(struct string_list **ref_excludes_p, const char *exclude)
+void clear_ref_exclusions(struct ref_exclusions *exclusions)
 {
-	if (!*ref_excludes_p) {
-		CALLOC_ARRAY(*ref_excludes_p, 1);
-		(*ref_excludes_p)->strdup_strings = 1;
-	}
-	string_list_append(*ref_excludes_p, exclude);
+	string_list_clear(&exclusions->excluded_refs, 0);
+}
+
+void add_ref_exclusion(struct ref_exclusions *exclusions, const char *exclude)
+{
+	string_list_append(&exclusions->excluded_refs, exclude);
 }
 
 struct all_refs_cb {
@@ -1563,7 +1558,7 @@ static int handle_one_ref(const char *path, const struct object_id *oid,
 	struct all_refs_cb *cb = cb_data;
 	struct object *object;
 
-	if (ref_excluded(cb->all_revs->ref_excludes, path))
+	if (ref_excluded(&cb->all_revs->ref_excludes, path))
 	    return 0;
 
 	object = get_reference(cb->all_revs, path, oid, cb->all_flags);
@@ -1901,6 +1896,7 @@ void repo_init_revisions(struct repository *r,
 
 	init_display_notes(&revs->notes_opt);
 	list_objects_filter_init(&revs->filter);
+	init_ref_exclusions(&revs->ref_excludes);
 }
 
 static void add_pending_commit_list(struct rev_info *revs,
@@ -2689,10 +2685,10 @@ static int handle_revision_pseudo_opt(struct rev_info *revs,
 			init_all_refs_cb(&cb, revs, *flags);
 			other_head_refs(handle_one_ref, &cb);
 		}
-		clear_ref_exclusion(&revs->ref_excludes);
+		clear_ref_exclusions(&revs->ref_excludes);
 	} else if (!strcmp(arg, "--branches")) {
 		handle_refs(refs, revs, *flags, refs_for_each_branch_ref);
-		clear_ref_exclusion(&revs->ref_excludes);
+		clear_ref_exclusions(&revs->ref_excludes);
 	} else if (!strcmp(arg, "--bisect")) {
 		read_bisect_terms(&term_bad, &term_good);
 		handle_refs(refs, revs, *flags, for_each_bad_bisect_ref);
@@ -2701,15 +2697,15 @@ static int handle_revision_pseudo_opt(struct rev_info *revs,
 		revs->bisect = 1;
 	} else if (!strcmp(arg, "--tags")) {
 		handle_refs(refs, revs, *flags, refs_for_each_tag_ref);
-		clear_ref_exclusion(&revs->ref_excludes);
+		clear_ref_exclusions(&revs->ref_excludes);
 	} else if (!strcmp(arg, "--remotes")) {
 		handle_refs(refs, revs, *flags, refs_for_each_remote_ref);
-		clear_ref_exclusion(&revs->ref_excludes);
+		clear_ref_exclusions(&revs->ref_excludes);
 	} else if ((argcount = parse_long_opt("glob", argv, &optarg))) {
 		struct all_refs_cb cb;
 		init_all_refs_cb(&cb, revs, *flags);
 		for_each_glob_ref(handle_one_ref, optarg, &cb);
-		clear_ref_exclusion(&revs->ref_excludes);
+		clear_ref_exclusions(&revs->ref_excludes);
 		return argcount;
 	} else if ((argcount = parse_long_opt("exclude", argv, &optarg))) {
 		add_ref_exclusion(&revs->ref_excludes, optarg);
@@ -2718,17 +2714,17 @@ static int handle_revision_pseudo_opt(struct rev_info *revs,
 		struct all_refs_cb cb;
 		init_all_refs_cb(&cb, revs, *flags);
 		for_each_glob_ref_in(handle_one_ref, optarg, "refs/heads/", &cb);
-		clear_ref_exclusion(&revs->ref_excludes);
+		clear_ref_exclusions(&revs->ref_excludes);
 	} else if (skip_prefix(arg, "--tags=", &optarg)) {
 		struct all_refs_cb cb;
 		init_all_refs_cb(&cb, revs, *flags);
 		for_each_glob_ref_in(handle_one_ref, optarg, "refs/tags/", &cb);
-		clear_ref_exclusion(&revs->ref_excludes);
+		clear_ref_exclusions(&revs->ref_excludes);
 	} else if (skip_prefix(arg, "--remotes=", &optarg)) {
 		struct all_refs_cb cb;
 		init_all_refs_cb(&cb, revs, *flags);
 		for_each_glob_ref_in(handle_one_ref, optarg, "refs/remotes/", &cb);
-		clear_ref_exclusion(&revs->ref_excludes);
+		clear_ref_exclusions(&revs->ref_excludes);
 	} else if (!strcmp(arg, "--reflog")) {
 		add_reflogs_to_pending(revs, *flags);
 	} else if (!strcmp(arg, "--indexed-objects")) {
diff --git a/revision.h b/revision.h
index afe1b77985..5c8ab16047 100644
--- a/revision.h
+++ b/revision.h
@@ -81,6 +81,21 @@ struct rev_cmdline_info {
 	} *rev;
 };
 
+struct ref_exclusions {
+	/*
+	 * Excluded refs is a list of wildmatch patterns. If any of the
+	 * patterns matches, the reference will be excluded.
+	 */
+	struct string_list excluded_refs;
+};
+
+/**
+ * Initialize a `struct ref_exclusions` with a macro.
+ */
+#define REF_EXCLUSIONS_INIT { \
+	.excluded_refs = STRING_LIST_INIT_DUP, \
+}
+
 struct oidset;
 struct topo_walk_info;
 
@@ -103,7 +118,7 @@ struct rev_info {
 	struct list_objects_filter_options filter;
 
 	/* excluding from --branches, --refs, etc. expansion */
-	struct string_list *ref_excludes;
+	struct ref_exclusions ref_excludes;
 
 	/* Basic information */
 	const char *prefix;
@@ -439,12 +454,12 @@ void mark_trees_uninteresting_sparse(struct repository *r, struct oidset *trees)
 void show_object_with_name(FILE *, struct object *, const char *);
 
 /**
- * Helpers to check if a "struct string_list" item matches with
- * wildmatch().
+ * Helpers to check if a reference should be excluded.
  */
-int ref_excluded(struct string_list *, const char *path);
-void clear_ref_exclusion(struct string_list **);
-void add_ref_exclusion(struct string_list **, const char *exclude);
+int ref_excluded(const struct ref_exclusions *exclusions, const char *path);
+void init_ref_exclusions(struct ref_exclusions *);
+void clear_ref_exclusions(struct ref_exclusions *);
+void add_ref_exclusion(struct ref_exclusions *, const char *exclude);
 
 /**
  * This function can be used if you want to add commit objects as revision