diff --submodule: split into bite-sized pieces

Introduce two functions:

 - prepare_submodule_summary prepares the revision walker
   to list changes in a submodule.  That is, it:

   * finds merge bases between the commits pointed to this
     path from before ("left") and after ("right") the change;
   * checks whether this is a fast-forward or fast-backward;
   * prepares a revision walk to list commits in the symmetric
     difference between the commits at each endpoint.

   It returns nonzero on error.

 - print_submodule_summary runs the revision walk and saves
   the result to a strbuf in --left-right format.

The goal is just readability.  No functional change intended.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Acked-by: Jens Lehmann <Jens.Lehmann@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/submodule.c b/submodule.c
index 6f1c10722f744f4a27f18dae4867b15ecbf57d49..e9f2b19e1c867b870b0b5f3ef3db3c871fe20689 100644 (file)
--- a/submodule.c
+++ b/submodule.c
@@ -152,17 +152,69 @@ void handle_ignore_submodules_arg(struct diff_options *diffopt,
                die("bad --ignore-submodules argument: %s", arg);
 }
 
+static int prepare_submodule_summary(struct rev_info *rev, const char *path,
+               struct commit *left, struct commit *right,
+               int *fast_forward, int *fast_backward)
+{
+       struct commit_list *merge_bases, *list;
+
+       init_revisions(rev, NULL);
+       setup_revisions(0, NULL, rev, NULL);
+       rev->left_right = 1;
+       rev->first_parent_only = 1;
+       left->object.flags |= SYMMETRIC_LEFT;
+       add_pending_object(rev, &left->object, path);
+       add_pending_object(rev, &right->object, path);
+       merge_bases = get_merge_bases(left, right, 1);
+       if (merge_bases) {
+               if (merge_bases->item == left)
+                       *fast_forward = 1;
+               else if (merge_bases->item == right)
+                       *fast_backward = 1;
+       }
+       for (list = merge_bases; list; list = list->next) {
+               list->item->object.flags |= UNINTERESTING;
+               add_pending_object(rev, &list->item->object,
+                       sha1_to_hex(list->item->object.sha1));
+       }
+       return prepare_revision_walk(rev);
+}
+
+static void print_submodule_summary(struct rev_info *rev, FILE *f,
+               const char *del, const char *add, const char *reset)
+{
+       static const char format[] = "  %m %s";
+       struct strbuf sb = STRBUF_INIT;
+       struct commit *commit;
+
+       while ((commit = get_revision(rev))) {
+               struct pretty_print_context ctx = {0};
+               ctx.date_mode = rev->date_mode;
+               strbuf_setlen(&sb, 0);
+               if (commit->object.flags & SYMMETRIC_LEFT) {
+                       if (del)
+                               strbuf_addstr(&sb, del);
+               }
+               else if (add)
+                       strbuf_addstr(&sb, add);
+               format_commit_message(commit, format, &sb, &ctx);
+               if (reset)
+                       strbuf_addstr(&sb, reset);
+               strbuf_addch(&sb, '\n');
+               fprintf(f, "%s", sb.buf);
+       }
+       strbuf_release(&sb);
+}
+
 void show_submodule_summary(FILE *f, const char *path,
                unsigned char one[20], unsigned char two[20],
                unsigned dirty_submodule,
                const char *del, const char *add, const char *reset)
 {
        struct rev_info rev;
-       struct commit *commit, *left = left, *right = right;
-       struct commit_list *merge_bases, *list;
+       struct commit *left = left, *right = right;
        const char *message = NULL;
        struct strbuf sb = STRBUF_INIT;
-       static const char *format = "  %m %s";
        int fast_forward = 0, fast_backward = 0;
 
        if (is_null_sha1(two))
@@ -175,29 +227,10 @@ void show_submodule_summary(FILE *f, const char *path,
                 !(right = lookup_commit_reference(two)))
                message = "(commits not present)";
 
-       if (!message) {
-               init_revisions(&rev, NULL);
-               setup_revisions(0, NULL, &rev, NULL);
-               rev.left_right = 1;
-               rev.first_parent_only = 1;
-               left->object.flags |= SYMMETRIC_LEFT;
-               add_pending_object(&rev, &left->object, path);
-               add_pending_object(&rev, &right->object, path);
-               merge_bases = get_merge_bases(left, right, 1);
-               if (merge_bases) {
-                       if (merge_bases->item == left)
-                               fast_forward = 1;
-                       else if (merge_bases->item == right)
-                               fast_backward = 1;
-               }
-               for (list = merge_bases; list; list = list->next) {
-                       list->item->object.flags |= UNINTERESTING;
-                       add_pending_object(&rev, &list->item->object,
-                               sha1_to_hex(list->item->object.sha1));
-               }
-               if (prepare_revision_walk(&rev))
-                       message = "(revision walker failed)";
-       }
+       if (!message &&
+           prepare_submodule_summary(&rev, path, left, right,
+                                       &fast_forward, &fast_backward))
+               message = "(revision walker failed)";
 
        if (dirty_submodule & DIRTY_SUBMODULE_UNTRACKED)
                fprintf(f, "Submodule %s contains untracked content\n", path);
@@ -221,25 +254,11 @@ void show_submodule_summary(FILE *f, const char *path,
        fwrite(sb.buf, sb.len, 1, f);
 
        if (!message) {
-               while ((commit = get_revision(&rev))) {
-                       struct pretty_print_context ctx = {0};
-                       ctx.date_mode = rev.date_mode;
-                       strbuf_setlen(&sb, 0);
-                       if (commit->object.flags & SYMMETRIC_LEFT) {
-                               if (del)
-                                       strbuf_addstr(&sb, del);
-                       }
-                       else if (add)
-                               strbuf_addstr(&sb, add);
-                       format_commit_message(commit, format, &sb, &ctx);
-                       if (reset)
-                               strbuf_addstr(&sb, reset);
-                       strbuf_addch(&sb, '\n');
-                       fprintf(f, "%s", sb.buf);
-               }
+               print_submodule_summary(&rev, f, del, add, reset);
                clear_commit_marks(left, ~0);
                clear_commit_marks(right, ~0);
        }
+
        strbuf_release(&sb);
 }