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, 39 deletions

diff --git a/src/crlf.c b/src/crlf.c
index cfc2d1eb1..1242450d8 100644
--- a/src/crlf.c
+++ b/src/crlf.c
@@ -74,39 +74,6 @@ static int crlf_input_action(struct crlf_attrs *ca)
 	return ca->crlf_action;
 }
 
-static int crlf_load_attributes(
-	struct crlf_attrs *ca, git_repository *repo, const char *path)
-{
-#define NUM_CONV_ATTRS 3
-
-	static const char *attr_names[NUM_CONV_ATTRS] = {
-		"crlf", "eol", "text",
-	};
-
-	const char *attr_vals[NUM_CONV_ATTRS];
-	int error;
-
-	error = git_attr_get_many(attr_vals,
-		repo, 0, path, NUM_CONV_ATTRS, attr_names);
-
-	if (error == GIT_ENOTFOUND) {
-		ca->crlf_action = GIT_CRLF_GUESS;
-		ca->eol = GIT_EOL_UNSET;
-		return 0;
-	}
-
-	if (error == 0) {
-		ca->crlf_action = check_crlf(attr_vals[2]); /* text */
-		if (ca->crlf_action == GIT_CRLF_GUESS)
-			ca->crlf_action = check_crlf(attr_vals[0]); /* clrf */
-
-		ca->eol = check_eol(attr_vals[1]); /* eol */
-		return 0;
-	}
-
-	return -1;
-}
-
 static int has_cr_in_index(const git_filter_source *src)
 {
 	git_repository *repo = git_filter_source_repo(src);
@@ -283,7 +250,8 @@ static int crlf_check(
 	git_filter        *self,
 	void              **payload, /* points to NULL ptr on entry, may be set */
 	git_filter_mode_t mode,
-	const git_filter_source *src)
+	const git_filter_source *src,
+	const char **attr_values)
 {
 	int error;
 	struct crlf_attrs ca;
@@ -291,11 +259,16 @@ static int crlf_check(
 	GIT_UNUSED(self);
 	GIT_UNUSED(mode);
 
-	/* Load gitattributes for the path */
-	error = crlf_load_attributes(
-		&ca, git_filter_source_repo(src), git_filter_source_path(src));
-	if (error < 0)
-		return error;
+	if (!attr_values) {
+		ca.crlf_action = GIT_CRLF_GUESS;
+		ca.eol = GIT_EOL_UNSET;
+	} else {
+		ca.crlf_action = check_crlf(attr_values[2]); /* text */
+		if (ca.crlf_action == GIT_CRLF_GUESS)
+			ca.crlf_action = check_crlf(attr_values[0]); /* clrf */
+		ca.eol = check_eol(attr_values[1]); /* eol */
+	}
+	ca.auto_crlf = GIT_AUTO_CRLF_DEFAULT;
 
 	/*
 	 * Use the core Git logic to see if we should perform CRLF for this file
@@ -350,7 +323,11 @@ static void crlf_cleanup(
 git_filter *git_crlf_filter_new(void)
 {
 	struct crlf_filter *f = git__calloc(1, sizeof(struct crlf_filter));
+
 	f->f.version = GIT_FILTER_VERSION;
+	f->f.attributes = "crlf eol text";
+	f->f.initialize = NULL;
+	f->f.shutdown   = NULL;
 	f->f.check   = crlf_check;
 	f->f.apply   = crlf_apply;
 	f->f.cleanup = crlf_cleanup;