Adding git_config_foreach_match() iteration fn

Adding a new config iteration function that let's you iterate
over just the config entries that match a particular regular
expression.  The old foreach becomes a simple use of this with
an empty pattern.

This also fixes an apparent bug in the existing `git_config_foreach`
where returning a non-zero value from the iteration callback was
not correctly aborting the iteration and the returned value was
not being propogated back to the caller of foreach.

Added to tests to cover all these changes.

1 files changed, 30 insertions, 7 deletions

diff --git a/src/config_file.c b/src/config_file.c
index fd1aa8d08..1f3ebfca9 100644
--- a/src/config_file.c
+++ b/src/config_file.c
@@ -188,25 +188,46 @@ static void backend_free(git_config_file *_backend)
 	git__free(backend);
 }
 
-static int file_foreach(git_config_file *backend, int (*fn)(const char *, const char *, void *), void *data)
+static int file_foreach(
+	git_config_file *backend,
+	const char *regexp,
+	int (*fn)(const char *, const char *, void *),
+	void *data)
 {
 	diskfile_backend *b = (diskfile_backend *)backend;
 	cvar_t *var;
 	const char *key;
+	regex_t regex;
+	int result = 0;
 
 	if (!b->values)
 		return 0;
 
+	if (regexp != NULL) {
+		if ((result = regcomp(&regex, regexp, REG_EXTENDED)) < 0) {
+			giterr_set_regex(&regex, result);
+			regfree(&regex);
+			return -1;
+		}
+	}
+
 	git_strmap_foreach(b->values, key, var,
-		do {
-			if (fn(key, var->value, data) < 0)
-				break;
+		for (; var != NULL; var = CVAR_LIST_NEXT(var)) {
+			/* skip non-matching keys if regexp was provided */
+			if (regexp && regexec(&regex, key, 0, NULL, 0) != 0)
+				continue;
 
-			var = CVAR_LIST_NEXT(var);
-		} while (var != NULL);
+			/* abort iterator on non-zero return value */
+			if ((result = fn(key, var->value, data)) != 0)
+				goto cleanup;
+		}
 	);
 
-	return 0;
+cleanup:
+	if (regexp != NULL)
+		regfree(&regex);
+
+	return result;
 }
 
 static int config_set(git_config_file *cfg, const char *name, const char *value)
@@ -337,6 +358,7 @@ static int config_get_multivar(
 		result = regcomp(&regex, regex_str, REG_EXTENDED);
 		if (result < 0) {
 			giterr_set_regex(&regex, result);
+			regfree(&regex);
 			return -1;
 		}
 
@@ -396,6 +418,7 @@ static int config_set_multivar(
 	if (result < 0) {
 		git__free(key);
 		giterr_set_regex(&preg, result);
+		regfree(&preg);
 		return -1;
 	}