[PATCH v3 1/7] submodule: add a print_config_from_gitmodules() helper

[Antonio Ospite <ao2@ao2.it>]

Add a new print_config_from_gitmodules() helper function to print values
from .gitmodules just like "git config -f .gitmodules" would.

This will be used by a new submodule--helper subcommand to be able to
access the .gitmodules file in a more controlled way.

Signed-off-by: Antonio Ospite <ao2@ao2.it>
---
 submodule-config.c | 25 +++++++++++++++++++++++++
 submodule-config.h |  2 ++
 2 files changed, 27 insertions(+)

diff --git a/submodule-config.c b/submodule-config.c
index fc2c41b947..eef96c4198 100644
--- a/submodule-config.c
+++ b/submodule-config.c
@@ -682,6 +682,31 @@ void submodule_free(struct repository *r)
 		submodule_cache_clear(r->submodule_cache);
 }
 
+static int config_print_callback(const char *key_, const char *value_, void *cb_data)
+{
+	char *key = cb_data;
+
+	if (!strcmp(key, key_))
+		printf("%s\n", value_);
+
+	return 0;
+}
+
+int print_config_from_gitmodules(const char *key)
+{
+	int ret;
+	char *store_key;
+
+	ret = git_config_parse_key(key, &store_key, NULL);
+	if (ret < 0)
+		return CONFIG_INVALID_KEY;
+
+	config_from_gitmodules(config_print_callback, the_repository, store_key);
+
+	free(store_key);
+	return 0;
+}
+
 struct fetch_config {
 	int *max_children;
 	int *recurse_submodules;
diff --git a/submodule-config.h b/submodule-config.h
index dc7278eea4..ed40e9a478 100644
--- a/submodule-config.h
+++ b/submodule-config.h
@@ -56,6 +56,8 @@ void submodule_free(struct repository *r);
  */
 int check_submodule_name(const char *name);
 
+int print_config_from_gitmodules(const char *key);
+
 /*
  * Note: these helper functions exist solely to maintain backward
  * compatibility with 'fetch' and 'update_clone' storing configuration in
-- 
2.18.0