protobuf/upb/pb/glue.h

/*
** upb's core components like upb_decoder and upb_msg are carefully designed to
** avoid depending on each other for maximum orthogonality.  In other words,
** you can use a upb_decoder to decode into *any* kind of structure; upb_msg is
** just one such structure.  A upb_msg can be serialized/deserialized into any
** format, protobuf binary format is just one such format.
**
** However, for convenience we provide functions here for doing common
** operations like deserializing protobuf binary format into a upb_msg.  The
** compromise is that this file drags in almost all of upb as a dependency,
** which could be undesirable if you're trying to use a trimmed-down build of
** upb.
**
** While these routines are convenient, they do not reuse any encoding/decoding
** state.  For example, if a decoder is JIT-based, it will be re-JITted every
** time these functions are called.  For this reason, if you are parsing lots
** of data and efficiency is an issue, these may not be the best functions to
** use (though they are useful for prototyping, before optimizing).
*/

#ifndef UPB_GLUE_H
#define UPB_GLUE_H

#include <stdbool.h>
#include "upb/symtab.h"

#ifdef __cplusplus
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);

#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 LoadDescriptorIntoSymtab(SymbolTable* s, const char* str,
                                     size_t len, Status* status) {
  return upb_load_descriptor_into_symtab(s, str, len, status);
}

/* 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);
}

}  /* namespace upb */

#endif

#endif  /* UPB_GLUE_H */