trailer: process command line trailer arguments

Parse the trailer command line arguments and put
the result into an arg_tok doubly linked list.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

trailer.c

@@ -1,4 +1,5 @@
 #include "cache.h"
+#include "string-list.h"
 /*
  * Copyright (c) 2013, 2014 Christian Couder <chriscool@tuxfamily.org>
  */
@@ -462,3 +463,114 @@ static int git_trailer_config(const char *conf_key, const char *value, void *cb)
 	}
 	return 0;
 }
+
+static int parse_trailer(struct strbuf *tok, struct strbuf *val, const char *trailer)
+{
+	size_t len;
+	struct strbuf seps = STRBUF_INIT;
+	strbuf_addstr(&seps, separators);
+	strbuf_addch(&seps, '=');
+	len = strcspn(trailer, seps.buf);
+	strbuf_release(&seps);
+	if (len == 0)
+		return error(_("empty trailer token in trailer '%s'"), trailer);
+	if (len < strlen(trailer)) {
+		strbuf_add(tok, trailer, len);
+		strbuf_trim(tok);
+		strbuf_addstr(val, trailer + len + 1);
+		strbuf_trim(val);
+	} else {
+		strbuf_addstr(tok, trailer);
+		strbuf_trim(tok);
+	}
+	return 0;
+}
+
+static const char *token_from_item(struct trailer_item *item, char *tok)
+{
+	if (item->conf.key)
+		return item->conf.key;
+	if (tok)
+		return tok;
+	return item->conf.name;
+}
+
+static struct trailer_item *new_trailer_item(struct trailer_item *conf_item,
+					     char *tok, char *val)
+{
+	struct trailer_item *new = xcalloc(sizeof(*new), 1);
+	new->value = val;
+
+	if (conf_item) {
+		duplicate_conf(&new->conf, &conf_item->conf);
+		new->token = xstrdup(token_from_item(conf_item, tok));
+		free(tok);
+	} else {
+		duplicate_conf(&new->conf, &default_conf_info);
+		new->token = tok;
+	}
+
+	return new;
+}
+
+static int token_matches_item(const char *tok, struct trailer_item *item, int tok_len)
+{
+	if (!strncasecmp(tok, item->conf.name, tok_len))
+		return 1;
+	return item->conf.key ? !strncasecmp(tok, item->conf.key, tok_len) : 0;
+}
+
+static struct trailer_item *create_trailer_item(const char *string)
+{
+	struct strbuf tok = STRBUF_INIT;
+	struct strbuf val = STRBUF_INIT;
+	struct trailer_item *item;
+	int tok_len;
+
+	if (parse_trailer(&tok, &val, string))
+		return NULL;
+
+	tok_len = token_len_without_separator(tok.buf, tok.len);
+
+	/* Lookup if the token matches something in the config */
+	for (item = first_conf_item; item; item = item->next) {
+		if (token_matches_item(tok.buf, item, tok_len))
+			return new_trailer_item(item,
+						strbuf_detach(&tok, NULL),
+						strbuf_detach(&val, NULL));
+	}
+
+	return new_trailer_item(NULL,
+				strbuf_detach(&tok, NULL),
+				strbuf_detach(&val, NULL));
+}
+
+static void add_trailer_item(struct trailer_item **first,
+			     struct trailer_item **last,
+			     struct trailer_item *new)
+{
+	if (!new)
+		return;
+	if (!*last) {
+		*first = new;
+		*last = new;
+	} else {
+		(*last)->next = new;
+		new->previous = *last;
+		*last = new;
+	}
+}
+
+static struct trailer_item *process_command_line_args(struct string_list *trailers)
+{
+	struct trailer_item *arg_tok_first = NULL;
+	struct trailer_item *arg_tok_last = NULL;
+	struct string_list_item *tr;
+
+	for_each_string_list_item(tr, trailers) {
+		struct trailer_item *new = create_trailer_item(tr->string);
+		add_trailer_item(&arg_tok_first, &arg_tok_last, new);
+	}
+
+	return arg_tok_first;
+}