[PATCH v4 06/17] trailer: parse trailers from input file

@@ -439,3 +439,65 @@ 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 (strbuf_isspace(lines[start])) {
+			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);
+	}
+}