Pass the upb_fielddef* to the endmsg callback.

src/upb_decoder.c

@@ -197,9 +197,8 @@ static upb_flow_t upb_push(upb_decoder *d, upb_fielddef *f,
       UPB_GROUP_END_OFFSET :
       d->buf_stream_offset + (d->ptr - upb_string_getrobuf(d->buf)) +
           upb_value_getint32(submsg_len);
-  upb_msgdef *md = upb_downcast_msgdef(f->def);
-  d->top->msgdef = md;
-  d->msgdef = md;
+  d->top->f = f;
+  d->msgdef = upb_downcast_msgdef(f->def);
   upb_dstate_setmsgend(d);
   upb_flow_t ret = upb_dispatch_startsubmsg(&d->dispatcher, f);
   if (ret == UPB_SKIPSUBMSG) {
@@ -217,9 +216,9 @@ static upb_flow_t upb_push(upb_decoder *d, upb_fielddef *f,
 
 static upb_flow_t upb_pop(upb_decoder *d) {
   --d->top;
+  d->msgdef = upb_downcast_msgdef(d->top->f->def);
   upb_dstate_setmsgend(d);
-  d->msgdef = d->top->msgdef;
-  return upb_dispatch_endsubmsg(&d->dispatcher);
+  return upb_dispatch_endsubmsg(&d->dispatcher, d->top->f);
 }
 
 void upb_decoder_run(upb_src *src, upb_status *status) {
@@ -228,7 +227,7 @@ void upb_decoder_run(upb_src *src, upb_status *status) {
   d->ptr = NULL;
   d->end = NULL;  // Force a buffer pull.
   d->submsg_end = (void*)0x1;  // But don't let end-of-message get triggered.
-  d->msgdef = d->top->msgdef;
+  d->msgdef = upb_downcast_msgdef(d->top->f->def);
 
 // TODO: handle UPB_SKIPSUBMSG
 #define CHECK_FLOW(expr) if ((expr) == UPB_BREAK) { /*assert(!upb_ok(status));*/ goto callback_err; }
@@ -373,9 +372,6 @@ void upb_decoder_sethandlers(upb_src *src, upb_handlers *handlers) {
   upb_dispatcher_reset(&d->dispatcher, handlers, true);
   d->top = d->stack;
   d->buf_stream_offset = 0;
-  // The top-level message is not delimited (we can keep receiving data for it
-  // indefinitely), so we treat it like a group.
-  d->top->end_offset = 0;
 }
 
 void upb_decoder_init(upb_decoder *d, upb_msgdef *msgdef) {
@@ -385,7 +381,9 @@ void upb_decoder_init(upb_decoder *d, upb_msgdef *msgdef) {
   };
   upb_src_init(&d->src, &vtbl);
   upb_dispatcher_init(&d->dispatcher);
-  d->stack[0].msgdef = msgdef;
+  d->f.def = UPB_UPCAST(msgdef);
+  d->stack[0].f = &d->f;
+  // Never want to end top-level message, so treat it like a group.
   d->stack[0].end_offset = UPB_GROUP_END_OFFSET;
   d->limit = &d->stack[UPB_MAX_NESTING];
   d->buf = NULL;

src/upb_decoder.h

@@ -30,7 +30,7 @@ extern "C" {
 // The decoder keeps a stack with one entry per level of recursion.
 // upb_decoder_frame is one frame of that stack.
 typedef struct {
-  upb_msgdef *msgdef;
+  upb_fielddef *f;
   size_t end_offset;  // For groups, 0.
 } upb_decoder_frame;
 
@@ -69,6 +69,8 @@ struct _upb_decoder {
   // Where we will store any errors that occur.
   upb_status *status;
 
+  // A fake fielddef for storing the msgdef for the top-level message.
+  upb_fielddef f;
   upb_decoder_frame stack[UPB_MAX_NESTING];
 };
 

src/upb_def.c

@@ -1471,7 +1471,7 @@ static void upb_baredecoder_run(upb_src *src, upb_status *status) {
     }
     // Detect end-of-submessage.
     while(d->offset >= *top) {
-      CHECK(upb_dispatch_endsubmsg(&d->dispatcher));
+      CHECK(upb_dispatch_endsubmsg(&d->dispatcher, &f));
       d->offset = *(top--);
     }
   }

src/upb_msg.c

@@ -270,7 +270,8 @@ static upb_flow_t upb_msgpopulator_startsubmsg(void *_p, upb_fielddef *f,
   return UPB_CONTINUE;
 }
 
-static upb_flow_t upb_msgpopulator_endsubmsg(void *_p) {
+static upb_flow_t upb_msgpopulator_endsubmsg(void *_p, upb_fielddef *f) {
+  (void)f;
   upb_msgpopulator *p = _p;
   --p->top;
   return UPB_CONTINUE;

src/upb_stream.h

@@ -98,7 +98,8 @@ typedef upb_flow_t (*upb_value_handler_t)(void *closure,
 typedef upb_flow_t (*upb_startsubmsg_handler_t)(void *closure,
                                                 struct _upb_fielddef *f,
                                                 upb_handlers *delegate_to);
-typedef upb_flow_t (*upb_endsubmsg_handler_t)(void *closure);
+typedef upb_flow_t (*upb_endsubmsg_handler_t)(void *closure,
+                                              struct _upb_fielddef *f);
 typedef upb_flow_t (*upb_unknownval_handler_t)(void *closure,
                                                upb_field_number_t fieldnum,
                                                upb_value val);
@@ -126,7 +127,7 @@ typedef upb_flow_t (*upb_unknownval_handler_t)(void *closure,
 //   return UPB_CONTINUE;
 // }
 //
-// static upb_flow_t endsubmsg(void *closure) {
+// static upb_flow_t endsubmsg(void *closure, upb_fielddef *f) {
 //   // Called when a submessage ends.
 //   return UPB_CONTINUE;
 // }
@@ -207,7 +208,8 @@ INLINE upb_flow_t upb_dispatch_startmsg(upb_dispatcher *d);
 INLINE upb_flow_t upb_dispatch_endmsg(upb_dispatcher *d);
 INLINE upb_flow_t upb_dispatch_startsubmsg(upb_dispatcher *d,
                                            struct _upb_fielddef *f);
-INLINE upb_flow_t upb_dispatch_endsubmsg(upb_dispatcher *d);
+INLINE upb_flow_t upb_dispatch_endsubmsg(upb_dispatcher *d,
+                                         struct _upb_fielddef *f);
 INLINE upb_flow_t upb_dispatch_value(upb_dispatcher *d, struct _upb_fielddef *f,
                                      upb_value val);
 INLINE upb_flow_t upb_dispatch_unknownval(upb_dispatcher *d,

src/upb_stream_vtbl.h

@@ -186,6 +186,12 @@ INLINE upb_flow_t upb_startsubmsg_nop(void *closure, struct _upb_fielddef *f,
   return UPB_CONTINUE;
 }
 
+INLINE upb_flow_t upb_endsubmsg_nop(void *closure, struct _upb_fielddef *f) {
+  (void)closure;
+  (void)f;
+  return UPB_CONTINUE;
+}
+
 INLINE upb_flow_t upb_unknownval_nop(void *closure, upb_field_number_t fieldnum,
                                      upb_value val) {
   (void)closure;
@@ -199,7 +205,7 @@ INLINE void upb_register_handlerset(upb_handlers *h, upb_handlerset *set) {
   if (!set->endmsg) set->endmsg = &upb_nop;
   if (!set->value) set->value = &upb_value_nop;
   if (!set->startsubmsg) set->startsubmsg = &upb_startsubmsg_nop;
-  if (!set->endsubmsg) set->endsubmsg = &upb_nop;
+  if (!set->endsubmsg) set->endsubmsg = &upb_endsubmsg_nop;
   if (!set->unknownval) set->unknownval = &upb_unknownval_nop;
   h->set = set;
 }
@@ -264,7 +270,8 @@ INLINE upb_flow_t upb_dispatch_startsubmsg(upb_dispatcher *d,
   return ret;
 }
 
-INLINE upb_flow_t upb_dispatch_endsubmsg(upb_dispatcher *d) {
+INLINE upb_flow_t upb_dispatch_endsubmsg(upb_dispatcher *d,
+                                         struct _upb_fielddef *f) {
   upb_flow_t ret;
   if (--d->top->depth == 0) {
     ret = d->top->handlers.set->endmsg(d->top->handlers.closure);
@@ -273,7 +280,7 @@ INLINE upb_flow_t upb_dispatch_endsubmsg(upb_dispatcher *d) {
     --d->top;
     assert(d->top >= d->stack);
   }
-  return d->top->handlers.set->endsubmsg(d->top->handlers.closure);
+  return d->top->handlers.set->endsubmsg(d->top->handlers.closure, f);
 }
 
 INLINE upb_flow_t upb_dispatch_value(upb_dispatcher *d,

src/upb_textprinter.c

@@ -107,8 +107,9 @@ err:
   return UPB_BREAK;
 }
 
-static upb_flow_t upb_textprinter_endsubmsg(void *_p)
+static upb_flow_t upb_textprinter_endsubmsg(void *_p, upb_fielddef *f)
 {
+  (void)f;
   upb_textprinter *p = _p;
   p->indent_depth--;
   upb_textprinter_indent(p);

tests/test_stream.c

@@ -53,7 +53,8 @@ static upb_flow_t startsubmsg(void *closure, struct _upb_fielddef *f,
   }
 }
 
-static upb_flow_t endsubmsg(void *closure) {
+static upb_flow_t endsubmsg(void *closure, struct _upb_fielddef *f) {
+  (void)f;
   test_data *d = closure;
   strappendf(d->str, "endsubmsg\n");
   return UPB_CONTINUE;
@@ -99,9 +100,9 @@ static void test_dispatcher() {
   data.should_delegate = false;
   upb_dispatch_startsubmsg(&d, NULL);
   upb_dispatch_value(&d, NULL, val);
-  upb_dispatch_endsubmsg(&d);
-  upb_dispatch_endsubmsg(&d);
-  upb_dispatch_endsubmsg(&d);
+  upb_dispatch_endsubmsg(&d, NULL);
+  upb_dispatch_endsubmsg(&d, NULL);
+  upb_dispatch_endsubmsg(&d, NULL);
   upb_dispatch_endmsg(&d);
 
   upb_string expected = UPB_STACK_STRING(