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/*
* upb - a minimalist implementation of protocol buffers.
*
* Copyright (c) 2011 Google Inc. See LICENSE for details.
* Author: Josh Haberman <jhaberman@gmail.com>
*
* upb::descriptor::Reader provides a way of building upb::Defs from
* data in descriptor.proto format.
*/
#ifndef UPB_DESCRIPTOR_H
#define UPB_DESCRIPTOR_H
#include "upb/sink.h"
#ifdef __cplusplus
namespace upb {
namespace descriptor {
class Reader;
} // namespace descriptor
} // namespace upb
typedef upb::descriptor::Reader upb_descreader;
#else
struct upb_descreader;
typedef struct upb_descreader upb_descreader;
#endif
// Internal-only structs used by Reader.
// upb_deflist is an internal-only dynamic array for storing a growing list of
// upb_defs.
typedef struct {
UPB_PRIVATE_FOR_CPP
upb_def **defs;
size_t len;
size_t size;
bool owned;
} upb_deflist;
// We keep a stack of all the messages scopes we are currently in, as well as
// the top-level file scope. This is necessary to correctly qualify the
// definitions that are contained inside. "name" tracks the name of the
// message or package (a bare name -- not qualified by any enclosing scopes).
typedef struct {
UPB_PRIVATE_FOR_CPP
char *name;
// Index of the first def that is under this scope. For msgdefs, the
// msgdef itself is at start-1.
int start;
} upb_descreader_frame;
// The maximum number of nested declarations that are allowed, ie.
// message Foo {
// message Bar {
// message Baz {
// }
// }
// }
//
// This is a resource limit that affects how big our runtime stack can grow.
// TODO: make this a runtime-settable property of the Reader instance.
#define UPB_MAX_MESSAGE_NESTING 64
#ifdef __cplusplus
// Class that receives descriptor data according to the descriptor.proto schema
// and use it to build upb::Defs corresponding to that schema.
class upb::descriptor::Reader {
public:
// These handlers must have come from NewHandlers() and must outlive the
// Reader.
//
// TODO: generate the handlers statically (like we do with the
// descriptor.proto defs) so that there is no need to pass this parameter (or
// to build/memory-manage the handlers at runtime at all). Unfortunately this
// is a bit tricky to implement for Handlers, but necessary to simplify this
// interface.
Reader(const Handlers* handlers, Status* status);
~Reader();
// Resets the reader's state and discards any defs it may have built.
void Reset();
// The reader's input; this is where descriptor.proto data should be sent.
Sink* input();
// Returns an array of all defs that have been parsed, and transfers ownership
// of them to "owner". The number of defs is stored in *n. Ownership of the
// returned array is retained and is invalidated by any other call into
// Reader.
//
// These defs are not frozen or resolved; they are ready to be added to a
// symtab.
upb::Def** GetDefs(void* owner, int* n);
// Builds and returns handlers for the reader, owned by "owner."
static Handlers* NewHandlers(const void* owner);
private:
#else
struct upb_descreader {
#endif
char sink[sizeof(upb_sink)];
upb_deflist defs;
upb_descreader_frame stack[UPB_MAX_MESSAGE_NESTING];
int stack_len;
uint32_t number;
char *name;
bool saw_number;
bool saw_name;
char *default_string;
upb_fielddef *f;
};
#ifdef __cplusplus
extern "C" {
#endif
// C API.
void upb_descreader_init(upb_descreader *r, const upb_handlers *handlers,
upb_status *status);
void upb_descreader_uninit(upb_descreader *r);
void upb_descreader_reset(upb_descreader *r);
upb_sink *upb_descreader_input(upb_descreader *r);
upb_def **upb_descreader_getdefs(upb_descreader *r, void *owner, int *n);
const upb_handlers *upb_descreader_newhandlers(const void *owner);
#ifdef __cplusplus
} // extern "C"
// C++ implementation details. /////////////////////////////////////////////////
namespace upb {
namespace descriptor {
inline Reader::Reader(const Handlers *h, Status *s) {
upb_descreader_init(this, h, s);
}
inline Reader::~Reader() { upb_descreader_uninit(this); }
inline void Reader::Reset() { upb_descreader_reset(this); }
inline Sink* Reader::input() { return upb_descreader_input(this); }
inline upb::Def** Reader::GetDefs(void* owner, int* n) {
return upb_descreader_getdefs(this, owner, n);
}
} // namespace descriptor
} // namespace upb
#endif
#endif // UPB_DESCRIPTOR_H
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