Add attributes to filters and fix registry

The filter registry as implemented was too primitive to actually
work once multiple filters were coming into play.  This expands
the implementation of the registry to handle multiple prioritized
filters correctly.

Additionally, this adds an "attributes" field to a filter that
makes it really really easy to implement filters that are based
on one or more attribute values.  The lookup and even simple value
checking can all happen automatically without custom filter code.

Lastly, with the registry improvements, this fills out the filter
lifecycle callbacks, with initialize and shutdown callbacks that
will be called before the filter is first used and after it is
last invoked.  This allows for system-wide initialization and
cleanup by the filter.

1 files changed, 16 insertions, 0 deletions

diff --git a/tests-clar/attr/repo.c b/tests-clar/attr/repo.c
index ca3e71e7f..ef2ad5ce9 100644
--- a/tests-clar/attr/repo.c
+++ b/tests-clar/attr/repo.c
@@ -100,6 +100,22 @@ void test_attr_repo__get_many(void)
 	cl_assert_equal_s("yes", values[3]);
 }
 
+void test_attr_repo__get_many_in_place(void)
+{
+	const char *vals[4] = { "repoattr", "rootattr", "missingattr", "subattr" };
+
+	/* it should be legal to look up values into the same array that has
+	 * the attribute names, overwriting each name as the value is found.
+	 */
+
+	cl_git_pass(git_attr_get_many(vals, g_repo, 0, "sub/subdir_test1", 4, vals));
+
+	cl_assert(GIT_ATTR_TRUE(vals[0]));
+	cl_assert(GIT_ATTR_TRUE(vals[1]));
+	cl_assert(GIT_ATTR_UNSPECIFIED(vals[2]));
+	cl_assert_equal_s("yes", vals[3]);
+}
+
 static int count_attrs(
 	const char *name,
 	const char *value,