From ec67ab630b31a89b698ad72ef4407828c01ae1b0 Mon Sep 17 00:00:00 2001
From: Erik Boasson <eb@ilities.com>
Date: Thu, 22 Feb 2024 16:57:17 +0100
Subject: [PATCH] Add support for optional members in dynsub

Signed-off-by: Erik Boasson <eb@ilities.com>
---
 examples/dynsub/print_sample.c       | 16 ++++++++++++++--
 examples/dynsub/type_cache.c         |  3 +++
 examples/dynsub/variouspub.c         | 16 ++++++++++++++--
 examples/dynsub/variouspub_types.idl |  7 +++++++
 4 files changed, 38 insertions(+), 4 deletions(-)

diff --git a/examples/dynsub/print_sample.c b/examples/dynsub/print_sample.c
index 2a5ab79228..8b0600d75c 100644
--- a/examples/dynsub/print_sample.c
+++ b/examples/dynsub/print_sample.c
@@ -180,8 +180,20 @@ static void print_sample1_to (const unsigned char *sample, const DDS_XTypes_Comp
       for (uint32_t i = 0; i < t->member_seq._length; i++)
       {
         const DDS_XTypes_CompleteStructMember *m = &t->member_seq._buffer[i];
-        c1.key = c->key && m->common.member_flags & DDS_XTypes_IS_KEY;
-        print_sample1_ti (p, &m->common.member_type_id, &c1, sep, *m->detail.name ? m->detail.name : NULL, false);
+        if (m->common.member_flags & DDS_XTypes_IS_OPTIONAL) {
+          void const * const *p1 = (const void *) align (p, &c1, _Alignof (void *), sizeof (void *));
+          if (*p1 == NULL) {
+            printf ("%s", sep);
+            if (*m->detail.name) printf ("\"%s\":", m->detail.name);
+            printf ("(nothing)");
+          } else {
+            struct context c2 = { .valid_data = c->valid_data, .key = false, .offset = 0, .maxalign = 1 };
+            print_sample1_ti (*p1, &m->common.member_type_id, &c2, sep, *m->detail.name ? m->detail.name : NULL, false);
+          }
+        } else {
+          c1.key = c->key && m->common.member_flags & DDS_XTypes_IS_KEY;
+          print_sample1_ti (p, &m->common.member_type_id, &c1, sep, *m->detail.name ? m->detail.name : NULL, false);
+        }
         sep = ",";
       }
       if (!is_base_type) printf ("}");
diff --git a/examples/dynsub/type_cache.c b/examples/dynsub/type_cache.c
index da845709d0..57cb9e9ba4 100644
--- a/examples/dynsub/type_cache.c
+++ b/examples/dynsub/type_cache.c
@@ -345,6 +345,9 @@ void build_typecache_to (const DDS_XTypes_CompleteTypeObject *typeobj, size_t *a
           const DDS_XTypes_CompleteStructMember *m = &t->member_seq._buffer[i];
           size_t a, s;
           build_typecache_ti (&m->common.member_type_id, &a, &s);
+          if (m->common.member_flags & DDS_XTypes_IS_OPTIONAL) {
+            a = _Alignof (void *); s = sizeof (void *);
+          }
           if (a > *align)
             *align = a;
           if (*size % a)
diff --git a/examples/dynsub/variouspub.c b/examples/dynsub/variouspub.c
index d5398d6b5e..e1773bcf31 100644
--- a/examples/dynsub/variouspub.c
+++ b/examples/dynsub/variouspub.c
@@ -85,6 +85,13 @@ static void *samples_c[] = {
   NULL
 };
 
+static int32_t long_4 = 4;
+static void *samples_M1_O[] = {
+  &(M1_O){ .x = NULL },
+  &(M1_O){ .x = &long_4 },
+  NULL
+};
+
 static struct tpentry {
   const char *name;
   const dds_topic_descriptor_t *descr;
@@ -94,6 +101,7 @@ static struct tpentry {
   { "A", &A_desc, samples_a, offsetof (A, count) },
   { "B", &B_desc, samples_b, offsetof (B, a.count) },
   { "C", &C_desc, samples_c, offsetof (C, b.a.count) },
+  { "M1::O", &M1_O_desc, samples_M1_O, SIZE_MAX },
   { NULL, NULL, NULL, 0 }
 };
 
@@ -145,8 +153,12 @@ int main (int argc, char **argv)
   {
     dds_return_t ret = 0;
     void *sample = tpentry->samples[sample_idx];
-    uint32_t *countp = (uint32_t *) ((unsigned char *) sample + tpentry->count_offset);
-    *countp = count++;
+    uint32_t * const countp =
+      (tpentry->count_offset != SIZE_MAX)
+      ? (uint32_t *) ((unsigned char *) sample + tpentry->count_offset)
+      : 0;
+    if (countp)
+      *countp = count++;
     if ((ret = dds_write (writer, sample)) < 0)
     {
       fprintf (stderr, "dds_write: %s\n", dds_strretcode (ret));
diff --git a/examples/dynsub/variouspub_types.idl b/examples/dynsub/variouspub_types.idl
index 1cf5baba74..b9f79c4c16 100644
--- a/examples/dynsub/variouspub_types.idl
+++ b/examples/dynsub/variouspub_types.idl
@@ -20,3 +20,10 @@ struct C {
   @key
   short k;
 };
+
+module M1 {
+  @appendable
+  struct O {
+    @optional long x;
+  };
+};