[PATCH v5 05/14] trailer: parse trailers from input file

[Christian Couder <chriscool@tuxfamily.org>]

This patch reads trailers from an input file, parses
them and puts the result into a doubly linked list.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
---
 trailer.c | 71 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 71 insertions(+)

diff --git a/trailer.c b/trailer.c
index 3fde21d..f59efd1 100644
--- a/trailer.c
+++ b/trailer.c
@@ -49,6 +49,13 @@ static inline size_t alnum_len(const char *buf, int len)
 	return (size_t) len + 1;
 }
 
+static inline int contains_only_spaces(const char *str)
+{
+	const char *s;
+	for (s = str; *s && isspace(*s); s++);
+	return !*s;
+}
+
 static void add_arg_to_infile(struct trailer_item *infile_tok,
 			      struct trailer_item *arg_tok)
 {
@@ -451,3 +458,67 @@ static struct trailer_item *process_command_line_args(int argc, const char **arg
 
 	return arg_tok_first;
 }
+
+static struct strbuf **read_input_file(const char *infile)
+{
+	struct strbuf sb = STRBUF_INIT;
+
+	if (strbuf_read_file(&sb, infile, 0) < 0)
+		die_errno(_("could not read input file '%s'"), infile);
+
+	return strbuf_split(&sb, '\n');
+}
+
+/*
+ * Return the the (0 based) index of the first trailer line
+ * or the line count if there are no trailers.
+ */
+static int find_trailer_start(struct strbuf **lines)
+{
+	int count, start, empty = 1;
+
+	/* Get the line count */
+	for (count = 0; lines[count]; count++);
+
+	/*
+	 * Get the start of the trailers by looking starting from the end
+	 * for a line with only spaces before lines with one ':'.
+	 */
+	for (start = count - 1; start >= 0; start--) {
+		if (contains_only_spaces(lines[start]->buf)) {
+			if (empty)
+				continue;
+			return start + 1;
+		}
+		if (strchr(lines[start]->buf, ':')) {
+			if (empty)
+				empty = 0;
+			continue;
+		}
+		return count;
+	}
+
+	return empty ? count : start + 1;
+}
+
+static void process_input_file(const char *infile,
+			       struct trailer_item **infile_tok_first,
+			       struct trailer_item **infile_tok_last)
+{
+	struct strbuf **lines = read_input_file(infile);
+	int start = find_trailer_start(lines);
+	int i;
+
+	/* Print non trailer lines as is */
+	for (i = 0; lines[i] && i < start; i++) {
+		printf("%s", lines[i]->buf);
+	}
+
+	/* Parse trailer lines */
+	for (i = start; lines[i]; i++) {
+		struct trailer_item *new = create_trailer_item(lines[i]->buf);
+		add_trailer_item(infile_tok_first, infile_tok_last, new);
+	}
+
+	strbuf_list_free(lines);
+}
-- 
1.8.5.2.206.g98f5689.dirty