interpret-trailers: add an option to show only existing trailers

diff --git a/trailer.c b/trailer.c
index 11f0b9fb40bcedbfcd3111fa8076ce0d9e1eb20f..847417ef89906694aaa3b27809d2a50b6afef789 100644 (file)
--- a/trailer.c
+++ b/trailer.c
@@ -163,13 +163,15 @@ static void print_tok_val(FILE *outfile, const char *tok, const char *val)
                fprintf(outfile, "%s%c %s\n", tok, separators[0], val);
 }
 
-static void print_all(FILE *outfile, struct list_head *head, int trim_empty)
+static void print_all(FILE *outfile, struct list_head *head,
+                     const struct process_trailer_options *opts)
 {
        struct list_head *pos;
        struct trailer_item *item;
        list_for_each(pos, head) {
                item = list_entry(pos, struct trailer_item, list);
-               if (!trim_empty || strlen(item->value) > 0)
+               if ((!opts->trim_empty || strlen(item->value) > 0) &&
+                   (!opts->only_trailers || item->token))
                        print_tok_val(outfile, item->token, item->value);
        }
 }
@@ -886,7 +888,8 @@ static int ends_with_blank_line(const char *buf, size_t len)
 
 static int process_input_file(FILE *outfile,
                              const char *str,
-                             struct list_head *head)
+                             struct list_head *head,
+                             const struct process_trailer_options *opts)
 {
        struct trailer_info info;
        struct strbuf tok = STRBUF_INIT;
@@ -896,9 +899,10 @@ static int process_input_file(FILE *outfile,
        trailer_info_get(&info, str);
 
        /* Print lines before the trailers as is */
-       fwrite(str, 1, info.trailer_start - str, outfile);
+       if (!opts->only_trailers)
+               fwrite(str, 1, info.trailer_start - str, outfile);
 
-       if (!info.blank_line_before_trailer)
+       if (!opts->only_trailers && !info.blank_line_before_trailer)
                fprintf(outfile, "\n");
 
        for (i = 0; i < info.trailer_nr; i++) {
@@ -913,7 +917,7 @@ static int process_input_file(FILE *outfile,
                        add_trailer_item(head,
                                         strbuf_detach(&tok, NULL),
                                         strbuf_detach(&val, NULL));
-               } else {
+               } else if (!opts->only_trailers) {
                        strbuf_addstr(&val, trailer);
                        strbuf_strip_suffix(&val, "\n");
                        add_trailer_item(head,
@@ -967,10 +971,11 @@ static FILE *create_in_place_tempfile(const char *file)
        return outfile;
 }
 
-void process_trailers(const char *file, int in_place, int trim_empty, struct string_list *trailers)
+void process_trailers(const char *file,
+                     const struct process_trailer_options *opts,
+                     struct string_list *trailers)
 {
        LIST_HEAD(head);
-       LIST_HEAD(arg_head);
        struct strbuf sb = STRBUF_INIT;
        int trailer_end;
        FILE *outfile = stdout;
@@ -979,24 +984,27 @@ void process_trailers(const char *file, int in_place, int trim_empty, struct str
 
        read_input_file(&sb, file);
 
-       if (in_place)
+       if (opts->in_place)
                outfile = create_in_place_tempfile(file);
 
        /* Print the lines before the trailers */
-       trailer_end = process_input_file(outfile, sb.buf, &head);
+       trailer_end = process_input_file(outfile, sb.buf, &head, opts);
 
-       process_command_line_args(&arg_head, trailers);
-
-       process_trailers_lists(&head, &arg_head);
+       if (!opts->only_input) {
+               LIST_HEAD(arg_head);
+               process_command_line_args(&arg_head, trailers);
+               process_trailers_lists(&head, &arg_head);
+       }
 
-       print_all(outfile, &head, trim_empty);
+       print_all(outfile, &head, opts);
 
        free_all(&head);
 
        /* Print the lines after the trailers as is */
-       fwrite(sb.buf + trailer_end, 1, sb.len - trailer_end, outfile);
+       if (!opts->only_trailers)
+               fwrite(sb.buf + trailer_end, 1, sb.len - trailer_end, outfile);
 
-       if (in_place)
+       if (opts->in_place)
                if (rename_tempfile(&trailers_tempfile, file))
                        die_errno(_("could not rename temporary file to %s"), file);