config: implement config snapshotting

In order to have consistent views of the config files for remotes,
submodules et al. and a configuration that represents what is currently
stored on-disk, we need a way to provide a view of the configuration
that does not change.

The goal here is to provide the snapshotting part by creating a
read-only copy of the state of the configuration at a particular point
in time, which does not change when a repository's main config changes.

1 files changed, 69 insertions, 0 deletions

diff --git a/tests/config/snapshot.c b/tests/config/snapshot.c
new file mode 100644
index 000000000..a9d3eadd3
--- /dev/null
+++ b/tests/config/snapshot.c
@@ -0,0 +1,69 @@
+#include "clar_libgit2.h"
+
+void test_config_snapshot__create_snapshot(void)
+{
+	int32_t tmp;
+	git_config *cfg, *snapshot;
+	const char *filename = "config-ext-change";
+
+	cl_git_mkfile(filename, "[old]\nvalue = 5\n");
+
+	cl_git_pass(git_config_open_ondisk(&cfg, filename));
+
+	cl_git_pass(git_config_get_int32(&tmp, cfg, "old.value"));
+	cl_assert_equal_i(5, tmp);
+
+	cl_git_pass(git_config_snapshot(&snapshot, cfg));
+
+	/* Change the value on the file itself (simulate external process) */
+	cl_git_mkfile(filename, "[old]\nvalue = 56\n");
+
+	cl_git_pass(git_config_get_int32(&tmp, cfg, "old.value"));
+	cl_assert_equal_i(5, tmp);
+
+	cl_git_pass(git_config_refresh(cfg));
+
+	cl_git_pass(git_config_get_int32(&tmp, cfg, "old.value"));
+	cl_assert_equal_i(56, tmp);
+
+	cl_git_pass(git_config_get_int32(&tmp, snapshot, "old.value"));
+	cl_assert_equal_i(5, tmp);
+	
+	git_config_free(snapshot);
+	git_config_free(cfg);
+}
+
+static int count_me(const git_config_entry *entry, void *payload)
+{
+	int *n = (int *) payload;
+
+	GIT_UNUSED(entry);
+
+	(*n)++;
+
+	return 0;
+}
+
+void test_config_snapshot__multivar(void)
+{
+	int count = 0;
+	git_config *cfg, *snapshot;
+	const char *filename = "config-file";
+
+	cl_git_mkfile(filename, "[old]\nvalue = 5\nvalue = 6\n");
+
+	cl_git_pass(git_config_open_ondisk(&cfg, filename));
+	cl_git_pass(git_config_get_multivar_foreach(cfg, "old.value", NULL, count_me, &count));
+
+	cl_assert_equal_i(2, count);
+
+	cl_git_pass(git_config_snapshot(&snapshot, cfg));
+	git_config_free(cfg);
+
+	count = 0;
+	cl_git_pass(git_config_get_multivar_foreach(snapshot, "old.value", NULL, count_me, &count));
+
+	cl_assert_equal_i(2, count);
+
+	git_config_free(snapshot);
+}