MINOR: acl: Extract the pattern parsing and indexation from the "acl_read_patterns_from_file()" function

With this split, the pattern indexation can apply to any source. The map
feature needs this functionality because the map cannot be loaded with the
same file format as the ones supported by acl_read_patterns_from_file().

The code was only moved to its own function, no functional changes were made.
diff --git a/src/acl.c b/src/acl.c
index 5c28e27..7b06e85 100644
--- a/src/acl.c
+++ b/src/acl.c
@@ -900,6 +900,50 @@
 	return expr;
 }
 
+/* return 1 if the process is ok
+ * return -1 if the parser fail. The err message is filled.
+ * return -2 if out of memory
+ */
+int acl_register_pattern(struct acl_expr *expr, char *text,
+                         struct acl_pattern **pattern,
+                         int patflags, char **err)
+{
+	const char *args[2];
+	int opaque = 0;
+
+	args[0] = text;
+	args[1] = "";
+
+	/* we keep the previous pattern along iterations as long as it's not used */
+	if (!*pattern)
+		*pattern = (struct acl_pattern *)malloc(sizeof(**pattern));
+	if (!*pattern)
+		return -1;
+
+	memset(*pattern, 0, sizeof(**pattern));
+	(*pattern)->flags = patflags;
+
+	if (!((*pattern)->flags & ACL_PAT_F_IGNORE_CASE) &&
+	    (expr->match == acl_match_str || expr->match == acl_match_ip)) {
+		/* we pre-set the data pointer to the tree's head so that functions
+		 * which are able to insert in a tree know where to do that.
+		 */
+		(*pattern)->flags |= ACL_PAT_F_TREE_OK;
+		(*pattern)->val.tree = &expr->pattern_tree;
+	}
+
+	(*pattern)->type = SMP_TYPES; /* unspecified type by default */
+	if (!expr->parse(args, *pattern, &opaque, err))
+		return -1;
+
+	/* if the parser did not feed the tree, let's chain the pattern to the list */
+	if (!((*pattern)->flags & ACL_PAT_F_TREE)) {
+		LIST_ADDQ(&expr->patterns, &(*pattern)->list);
+		*pattern = NULL; /* get a new one */
+	}
+
+	return 1;
+}
 
 /* Reads patterns from a file. If <err_msg> is non-NULL, an error message will
  * be returned there on errors and the caller will have to free it.
@@ -910,11 +954,11 @@
 {
 	FILE *file;
 	char *c;
-	const char *args[2];
+	char *arg;
 	struct acl_pattern *pattern;
-	int opaque;
 	int ret = 0;
 	int line = 0;
+	int code;
 
 	file = fopen(filename, "r");
 	if (!file) {
@@ -926,9 +970,7 @@
 	 * line. If the line contains spaces, they will be part of the pattern.
 	 * The pattern stops at the first CR, LF or EOF encountered.
 	 */
-	opaque = 0;
 	pattern = NULL;
-	args[1] = "";
 	while (fgets(trash.str, trash.size, file) != NULL) {
 		line++;
 		c = trash.str;
@@ -942,43 +984,23 @@
 			c++;
 
 
-		args[0] = c;
+		arg = c;
 		while (*c && *c != '\n' && *c != '\r')
 			c++;
 		*c = 0;
 
 		/* empty lines are ignored too */
-		if (c == args[0])
+		if (c == arg)
 			continue;
 
-		/* we keep the previous pattern along iterations as long as it's not used */
-		if (!pattern)
-			pattern = (struct acl_pattern *)malloc(sizeof(*pattern));
-		if (!pattern) {
+		code = acl_register_pattern(expr, arg, &pattern, patflags, err);
+		if (code == -2) {
 			memprintf(err, "out of memory when loading patterns from file <%s>", filename);
 			goto out_close;
 		}
-
-		memset(pattern, 0, sizeof(*pattern));
-		pattern->flags = patflags;
-
-		if (!(pattern->flags & ACL_PAT_F_IGNORE_CASE) &&
-		    (expr->match == acl_match_str || expr->match == acl_match_ip)) {
-			/* we pre-set the data pointer to the tree's head so that functions
-			 * which are able to insert in a tree know where to do that.
-			 */
-			pattern->flags |= ACL_PAT_F_TREE_OK;
-			pattern->val.tree = &expr->pattern_tree;
-		}
-
-		pattern->type = SMP_TYPES; /* unspecified type by default */
-		if (!expr->parse(args, pattern, &opaque, err))
+		else if (code < 0) {
+			memprintf(err, "%s when loading patterns from file <%s>", *err, filename);
 			goto out_free_pattern;
-
-		/* if the parser did not feed the tree, let's chain the pattern to the list */
-		if (!(pattern->flags & ACL_PAT_F_TREE)) {
-			LIST_ADDQ(&expr->patterns, &pattern->list);
-			pattern = NULL; /* get a new one */
 		}
 	}