mhshow: fix display of alternatives after certain nested multiparts

adjust return codes so that we now have a clear indication of whether
there was a hard error (NOTOK), a failure to display due to type
mismatch (DONE), or complete success (OK).  use those codes in
show_multi_internal() to decide whether we're finished with this
multipart or not.

prior to this change, it was impossible to show part 1.2 of a
message constructed like the following, because the disinction
between (the new, as described above) DONE and OK states was
lost while processing multipart/related part 1.1.
 msg part  type/subtype              size description
  28       multipart/mixed           1040
     1     multipart/alternative      623
     1.1   multipart/related          275
     1.1.1 text/html                  105
     1.2   text/plain                  33
     2     text/plain                  83

this fix is related to 9cc2510 and c9794733.  hopefully it's right
this time.

diff --git a/uip/mhshowsbr.c b/uip/mhshowsbr.c
index fe8552b..c0ce69f 100644 (file)
--- a/uip/mhshowsbr.c
+++ b/uip/mhshowsbr.c
@@ -22,6 +22,8 @@
 #endif /* ! HAVE_ICONV */
 
 extern int debugsw;
+extern int npart;
+extern int ntype;
 
 int nolist   = 0;
 
@@ -546,8 +548,9 @@ show_multi (CT ct, int alternate, int concatsw, int textonly, int inlineonly,
     if ((cp = context_find_by_type ("show", ci->ci_type, ci->ci_subtype)))
        return show_multi_aux (ct, alternate, cp, fmt);
 
-    if ((cp = ct->c_showproc))
+    if ((cp = ct->c_showproc)) {
        return show_multi_aux (ct, alternate, cp, fmt);
+    }
 
     /*
      * Use default method to display this multipart content.  Even
@@ -572,6 +575,8 @@ show_multi_internal (CT ct, int alternate, int concatsw, int textonly,
     struct multipart *m = (struct multipart *) ct->c_ctparams;
     struct part *part;
     int request_matched;
+    int display_success;
+    int ret;
     CT p;
 
     alternating = 0;
@@ -583,12 +588,13 @@ show_multi_internal (CT ct, int alternate, int concatsw, int textonly,
     }
 
     /*
-     * alternate   -> we are a part inside an multipart/alternative
+     * alternate   -> we are a part inside a multipart/alternative
      * alternating -> we are a multipart/alternative
      */
 
     result = alternate ? NOTOK : OK;
     request_matched = 0;
+    display_success = 0;
 
     for (part = m->mp_parts; part; part = part->mp_next) {
        p = part->mp_part;
@@ -596,19 +602,24 @@ show_multi_internal (CT ct, int alternate, int concatsw, int textonly,
        if (part_ok (p) && type_ok (p, 1)) {
            int inneresult;
 
-           request_matched = 1;
 
            inneresult = show_switch (p, nowalternate, concatsw, textonly,
                                      inlineonly, fmt);
            switch (inneresult) {
-               case NOTOK:
+               case NOTOK:  /* hard display error */
+                   request_matched = 1;
                    if (alternate && !alternating) {
                        result = NOTOK;
                        goto out;
                    }
                    continue;
 
-               case OK:
+               case DONE:  /* found no match on content type */
+                   continue;
+
+               case OK:  /* display successful */
+                   request_matched = 1;
+                   display_success = 1;
                    if (alternating) {
                        break;
                    }
@@ -623,7 +634,12 @@ show_multi_internal (CT ct, int alternate, int concatsw, int textonly,
        }
     }
 
-    if (alternating && !part && request_matched) {
+    /* we're supposed to be displaying at least something from a
+     * multipart.  if we've had parts to consider, and we've had no
+     * success, then we should complain.  we shouldn't complain if
+     * none of the parts matched any -part option or -type option.
+     */
+    if (alternating && request_matched && !display_success) {
        if (!alternate)
            content_error (NULL, ct, "don't know how to display any of the contents");
        result = NOTOK;
@@ -632,8 +648,9 @@ show_multi_internal (CT ct, int alternate, int concatsw, int textonly,
 
 out:
     /* if no parts matched what was requested, there can't have been
-     * any display errors, so we report OK. */
-    return request_matched ? result : OK;
+     * any display errors.  we report DONE rather than OK. */
+    ret = request_matched ? result : DONE;
+    return ret;
 }