trailer: move interpret_trailers() to interpret-trailers.c

The interpret-trailers.c builtin is the only place we need to call
interpret_trailers(), so move its definition there (together with a few
helper functions called only by it) and remove its external declaration
from <trailer.h>.

Several helper functions that are called by interpret_trailers() remain
in trailer.c because other callers in the same file still call them.
Declare them in <trailer.h> so that interpret_trailers() (now in
builtin/interpret-trailers.c) can continue calling them as a trailer API
user.

This enriches <trailer.h> with a more granular API, which can then be
unit-tested in the future (because interpret_trailers() by itself does
too many things to be able to be easily unit-tested).

Take this opportunity to demote some file-handling functions out of the
trailer API implementation, as these have nothing to do with trailers.

Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Linus Arver <linusa@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 17 insertions, 3 deletions

diff --git a/trailer.h b/trailer.h
index 027bf00282..c6d3ee49bb 100644
--- a/trailer.h
+++ b/trailer.h
@@ -81,15 +81,29 @@ struct process_trailer_options {
 
 #define PROCESS_TRAILER_OPTIONS_INIT {0}
 
-void interpret_trailers(const struct process_trailer_options *opts,
-			struct list_head *new_trailer_head,
-			const char *file);
+void parse_trailers_from_config(struct list_head *config_head);
+
+void parse_trailers_from_command_line_args(struct list_head *arg_head,
+					   struct list_head *new_trailer_head);
+
+void process_trailers_lists(struct list_head *head,
+			    struct list_head *arg_head);
+
+void parse_trailers(const struct process_trailer_options *,
+		    struct trailer_info *,
+		    const char *str,
+		    struct list_head *head);
 
 void trailer_info_get(struct trailer_info *info, const char *str,
 		      const struct process_trailer_options *opts);
 
 void trailer_info_release(struct trailer_info *info);
 
+void trailer_config_init(void);
+void format_trailers(const struct process_trailer_options *,
+		     struct list_head *trailers, FILE *outfile);
+void free_trailers(struct list_head *);
+
 /*
  * Format the trailers from the commit msg "msg" into the strbuf "out".
  * Note two caveats about "opts":