[PATCH v2 6/8] sparse-checkout: load sparse-checkout patterns

["Derrick Stolee via GitGitGadget" <gitgitgadget@gmail.com>]

From: Derrick Stolee <dstolee@microsoft.com>

A future feature will want to load the sparse-checkout patterns into a
pattern_list, but the current mechanism to do so is a bit complicated.
This is made difficult due to needing to find the sparse-checkout file
in different ways throughout the codebase.

The logic implemented in the new get_sparse_checkout_patterns() was
duplicated in populate_from_existing_patterns() in unpack-trees.c. Use
the new method instead, keeping the logic around handling the struct
unpack_trees_options.

The callers to get_sparse_checkout_filename() in
builtin/sparse-checkout.c manipulate the sparse-checkout file directly,
so it is not appropriate to replace logic in that file with
get_sparse_checkout_patterns().

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
---
 builtin/sparse-checkout.c |  5 -----
 dir.c                     | 17 +++++++++++++++++
 dir.h                     |  2 ++
 unpack-trees.c            |  6 +-----
 4 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/builtin/sparse-checkout.c b/builtin/sparse-checkout.c
index e3140db2a0a..2306a9ad98e 100644
--- a/builtin/sparse-checkout.c
+++ b/builtin/sparse-checkout.c
@@ -22,11 +22,6 @@ static char const * const builtin_sparse_checkout_usage[] = {
 	NULL
 };
 
-static char *get_sparse_checkout_filename(void)
-{
-	return git_pathdup("info/sparse-checkout");
-}
-
 static void write_patterns_to_file(FILE *fp, struct pattern_list *pl)
 {
 	int i;
diff --git a/dir.c b/dir.c
index d637461da5c..d153a63bbd1 100644
--- a/dir.c
+++ b/dir.c
@@ -2998,6 +2998,23 @@ void setup_standard_excludes(struct dir_struct *dir)
 	}
 }
 
+char *get_sparse_checkout_filename(void)
+{
+	return git_pathdup("info/sparse-checkout");
+}
+
+int get_sparse_checkout_patterns(struct pattern_list *pl)
+{
+	int res;
+	char *sparse_filename = get_sparse_checkout_filename();
+
+	pl->use_cone_patterns = core_sparse_checkout_cone;
+	res = add_patterns_from_file_to_list(sparse_filename, "", 0, pl, NULL);
+
+	free(sparse_filename);
+	return res;
+}
+
 int remove_path(const char *name)
 {
 	char *slash;
diff --git a/dir.h b/dir.h
index a3c40dec516..facfae47402 100644
--- a/dir.h
+++ b/dir.h
@@ -448,6 +448,8 @@ int is_empty_dir(const char *dir);
 
 void setup_standard_excludes(struct dir_struct *dir);
 
+char *get_sparse_checkout_filename(void);
+int get_sparse_checkout_patterns(struct pattern_list *pl);
 
 /* Constants for remove_dir_recursively: */
 
diff --git a/unpack-trees.c b/unpack-trees.c
index af6e9b9c2fd..837b8bb42fb 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -1549,14 +1549,10 @@ static void mark_new_skip_worktree(struct pattern_list *pl,
 static void populate_from_existing_patterns(struct unpack_trees_options *o,
 					    struct pattern_list *pl)
 {
-	char *sparse = git_pathdup("info/sparse-checkout");
-
-	pl->use_cone_patterns = core_sparse_checkout_cone;
-	if (add_patterns_from_file_to_list(sparse, "", 0, pl, NULL) < 0)
+	if (get_sparse_checkout_patterns(pl) < 0)
 		o->skip_sparse_checkout = 1;
 	else
 		o->pl = pl;
-	free(sparse);
 }
 
 
-- 
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