Added upb::FileDef, which represents the file defs are declared in.

It is entirely optional: MessageDef/EnumDef can still exist
on their own.  But this can represent a def's file when it is
desirable to do so (eg. for code generators).

This approach will require that we change the way we handle
extensions.  But I think it will be a good change overall.

Specifically, we previously handled extensions by duplicating
the extended message and then adding the extension as a regular
field to the duplicated message.  This required also duplicating
any messages that could reach the extended message.

In the new world we will need a way of declaring and looking up
extensions separately from the message being extended.

This change also involves some notable changes to the generated
code:

- files are now called foo.upbdefs.h instead of foo.upb.h.
  This reflects the fact that we might possibly generate several
  different output files for a .proto file, and this one is just
  for defs.

- we no longer generate selectors in the .h file.

- the upbdefs.c no longer vends a SymbolTable.  Now it vends the
  individual messages (and possibly a FileDef later).  I think this
  will compose better once we can generate files where one
  generated files imports another.

We also make the descriptor reader vend a list of FileDefs now.
This is the best conceptual match for parsing a FileDescriptorSet.

1 files changed, 23 insertions, 29 deletions

diff --git a/upb/pb/glue.h b/upb/pb/glue.h
index f65753c..014562b 100644
--- a/upb/pb/glue.h
+++ b/upb/pb/glue.h
@@ -25,49 +25,43 @@
 #include "upb/symtab.h"
 
 #ifdef __cplusplus
+#include <vector>
+
 extern "C" {
 #endif
 
-/* Loads all defs from the given protobuf binary descriptor, setting default
- * accessors and a default layout on all messages.  The caller owns the
- * returned array of defs, which will be of length *n.  On error NULL is
- * returned and status is set (if non-NULL). */
-upb_def **upb_load_defs_from_descriptor(const char *str, size_t len, int *n,
-                                        void *owner, upb_status *status);
-
-/* Like the previous but also adds the loaded defs to the given symtab. */
-bool upb_load_descriptor_into_symtab(upb_symtab *symtab, const char *str,
-                                     size_t len, upb_status *status);
-
-/* Like the previous but also reads the descriptor from the given filename. */
-bool upb_load_descriptor_file_into_symtab(upb_symtab *symtab, const char *fname,
-                                          upb_status *status);
-
-/* Reads the given filename into a character string, returning NULL if there
- * was an error. */
-char *upb_readfile(const char *filename, size_t *len);
+/* Loads a binary descriptor and returns a NULL-terminated array of unfrozen
+ * filedefs.  The caller owns the returned array. */
+upb_filedef **upb_loaddescriptor(const char *buf, size_t n, const void *owner,
+                                 upb_status *status);
 
 #ifdef __cplusplus
 }  /* extern "C" */
 
 namespace upb {
 
-/* All routines that load descriptors expect the descriptor to be a
- * FileDescriptorSet. */
-inline bool LoadDescriptorFileIntoSymtab(SymbolTable* s, const char *fname,
-                                         Status* status) {
-  return upb_load_descriptor_file_into_symtab(s, fname, status);
-}
+inline bool LoadDescriptor(const char* buf, size_t n, Status* status,
+                           std::vector<reffed_ptr<FileDef> >* files) {
+  FileDef** parsed_files = upb_loaddescriptor(buf, n, &parsed_files, status);
 
-inline bool LoadDescriptorIntoSymtab(SymbolTable* s, const char* str,
-                                     size_t len, Status* status) {
-  return upb_load_descriptor_into_symtab(s, str, len, status);
+  if (parsed_files) {
+    FileDef** p = parsed_files;
+    while (*p) {
+      files->push_back(reffed_ptr<FileDef>(*p, &parsed_files));
+      ++p;
+    }
+    free(parsed_files);
+    return true;
+  } else {
+    return false;
+  }
 }
 
 /* Templated so it can accept both string and std::string. */
 template <typename T>
-bool LoadDescriptorIntoSymtab(SymbolTable* s, const T& desc, Status* status) {
-  return upb_load_descriptor_into_symtab(s, desc.c_str(), desc.size(), status);
+bool LoadDescriptor(const T& desc, Status* status,
+                    std::vector<reffed_ptr<FileDef> >* files) {
+  return LoadDescriptor(desc.c_str(), desc.size(), status, files);
 }
 
 }  /* namespace upb */