Change the API for getting the bootstrapped defs.

The symtab that contains them is now hidden, and
you can look them up by name but there is no access
to the symtab itself, so there is no risk of
mutating it (by extending it, adding other defs
to it, etc).

1 files changed, 15 insertions, 12 deletions

diff --git a/src/upb_def.h b/src/upb_def.h
index db33fbb..121d5bc 100644
--- a/src/upb_def.h
+++ b/src/upb_def.h
@@ -276,7 +276,7 @@ void _upb_symtab_free(upb_symtab *s);  // Must not be called directly!
 
 INLINE void upb_symtab_ref(upb_symtab *s) { upb_atomic_ref(&s->refcount); }
 INLINE void upb_symtab_unref(upb_symtab *s) {
-  if(upb_atomic_unref(&s->refcount)) _upb_symtab_free(s);
+  if(s && upb_atomic_unref(&s->refcount)) _upb_symtab_free(s);
 }
 
 // Resolves the given symbol using the rules described in descriptor.proto,
@@ -314,17 +314,20 @@ upb_def **upb_symtab_getdefs(upb_symtab *s, int *count, upb_deftype_t type);
 // more useful?  Maybe it should be an option.
 void upb_symtab_addfds(upb_symtab *s, upb_src *desc, upb_status *status);
 
-// Adds defs for google.protobuf.FileDescriptorSet and friends to this symtab.
-// This is necessary for bootstrapping, since these are the upb_defs that
-// specify other defs and allow them to be loaded.
-void upb_symtab_add_descriptorproto(upb_symtab *s);
-
-// Returns the upb_msgdef for google.protobuf.FileDescriptorSet, which the
-// caller owns a ref on.  This is a convenience method that is equivalent to
-// looking up the symbol called "google.protobuf.FileDescriptorSet" yourself,
-// except that it only will return a def that was added by
-// upb_symtab_add_descriptorproto().
-upb_msgdef *upb_symtab_fds_def(upb_symtab *s);
+// Returns a def corresponding to the given name, from descriptor.proto.
+// upb internally bootstraps the defs in descriptor.proto, since they are
+// necessary for loading other descriptors.  The caller owns a ref on the
+// returned def (which is NULL if no such def exists in descriptor.proto).
+//
+// The name should *not* be qualified by the package, to promote
+// interoperability between the internal and external releases of Protocol
+// Buffers (inside Google, these are in the "proto2" package, externally they
+// are in "google.protobuf".
+upb_def *upb_getdescriptordef(upb_string *str);
+
+// A convenience method for getting the upb_def for FileDescriptorProto.
+// Return should never be NULL.
+upb_msgdef *upb_getfdsdef();
 
 
 /* upb_def casts **************************************************************/