[PATCH v5 05/17] sparse-checkout: add '--stdin' option to set subcommand

["Derrick Stolee via GitGitGadget" <gitgitgadget@xxxxxxxxx>]

From: Derrick Stolee <dstolee@xxxxxxxxxxxxx>

The 'git sparse-checkout set' subcommand takes a list of patterns
and places them in the sparse-checkout file. Then, it updates the
working directory to match those patterns. For a large list of
patterns, the command-line call can get very cumbersome.

Add a '--stdin' option to instead read patterns over standard in.

Signed-off-by: Derrick Stolee <dstolee@xxxxxxxxxxxxx>
---
 builtin/sparse-checkout.c          | 35 ++++++++++++++++++++++++++++--
 t/t1091-sparse-checkout-builtin.sh | 20 +++++++++++++++++
 2 files changed, 53 insertions(+), 2 deletions(-)

diff --git a/builtin/sparse-checkout.c b/builtin/sparse-checkout.c
index 834ee421f0..f2e2bd772d 100644
--- a/builtin/sparse-checkout.c
+++ b/builtin/sparse-checkout.c
@@ -154,6 +154,15 @@ static int write_patterns_and_update(struct pattern_list *pl)
 	return update_working_directory();
 }
 
+static char const * const builtin_sparse_checkout_set_usage[] = {
+	N_("git sparse-checkout set [--stdin|<patterns>]"),
+	NULL
+};
+
+static struct sparse_checkout_set_opts {
+	int use_stdin;
+} set_opts;
+
 static int sparse_checkout_set(int argc, const char **argv, const char *prefix)
 {
 	static const char *empty_base = "";
@@ -161,10 +170,32 @@ static int sparse_checkout_set(int argc, const char **argv, const char *prefix)
 	struct pattern_list pl;
 	int result;
 	int set_config = 0;
+
+	static struct option builtin_sparse_checkout_set_options[] = {
+		OPT_BOOL(0, "stdin", &set_opts.use_stdin,
+			 N_("read patterns from standard in")),
+		OPT_END(),
+	};
+
 	memset(&pl, 0, sizeof(pl));
 
-	for (i = 1; i < argc; i++)
-		add_pattern(argv[i], empty_base, 0, &pl, 0);
+	argc = parse_options(argc, argv, prefix,
+			     builtin_sparse_checkout_set_options,
+			     builtin_sparse_checkout_set_usage,
+			     PARSE_OPT_KEEP_UNKNOWN);
+
+	if (set_opts.use_stdin) {
+		struct strbuf line = STRBUF_INIT;
+
+		while (!strbuf_getline(&line, stdin)) {
+			size_t len;
+			char *buf = strbuf_detach(&line, &len);
+			add_pattern(buf, empty_base, 0, &pl, 0);
+		}
+	} else {
+		for (i = 0; i < argc; i++)
+			add_pattern(argv[i], empty_base, 0, &pl, 0);
+	}
 
 	if (!core_apply_sparse_checkout) {
 		sc_set_config(MODE_ALL_PATTERNS);
diff --git a/t/t1091-sparse-checkout-builtin.sh b/t/t1091-sparse-checkout-builtin.sh
index bf2dc55bb1..a9ff5eb9ec 100755
--- a/t/t1091-sparse-checkout-builtin.sh
+++ b/t/t1091-sparse-checkout-builtin.sh
@@ -128,4 +128,24 @@ test_expect_success 'set sparse-checkout using builtin' '
 	test_cmp expect dir
 '
 
+test_expect_success 'set sparse-checkout using --stdin' '
+	cat >expect <<-EOF &&
+		/*
+		!/*/
+		/folder1/
+		/folder2/
+	EOF
+	git -C repo sparse-checkout set --stdin <expect &&
+	git -C repo sparse-checkout list >actual &&
+	test_cmp expect actual &&
+	test_cmp expect repo/.git/info/sparse-checkout &&
+	ls repo >dir  &&
+	cat >expect <<-EOF &&
+		a
+		folder1
+		folder2
+	EOF
+	test_cmp expect dir
+'
+
 test_done
-- 
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