upb/decode.h

/*
 * Copyright (c) 2009-2021, Google LLC
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 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of Google LLC nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 */

/*
 * upb_decode: parsing into a upb_Message using a upb_MiniTable.
 */

#ifndef UPB_DECODE_H_
#define UPB_DECODE_H_

#include "upb/msg.h"

/* Must be last. */
#include "upb/port_def.inc"

#ifdef __cplusplus
extern "C" {
#endif

enum {
  /* If set, strings will alias the input buffer instead of copying into the
   * arena. */
  kUpb_DecodeOption_AliasString = 1,

  /* If set, the parse will return failure if any message is missing any
   * required fields when the message data ends.  The parse will still continue,
   * and the failure will only be reported at the end.
   *
   * IMPORTANT CAVEATS:
   *
   * 1. This can throw a false positive failure if an incomplete message is seen
   *    on the wire but is later completed when the sub-message occurs again.
   *    For this reason, a second pass is required to verify a failure, to be
   *    truly robust.
   *
   * 2. This can return a false success if you are decoding into a message that
   *    already has some sub-message fields present.  If the sub-message does
   *    not occur in the binary payload, we will never visit it and discover the
   *    incomplete sub-message.  For this reason, this check is only useful for
   *    implemting ParseFromString() semantics.  For MergeFromString(), a
   *    post-parse validation step will always be necessary. */
  kUpb_DecodeOption_CheckRequired = 2,
};

#define UPB_DECODE_MAXDEPTH(depth) ((depth) << 16)

typedef enum {
  kUpb_DecodeStatus_Ok = 0,
  kUpb_DecodeStatus_Malformed = 1,         // Wire format was corrupt
  kUpb_DecodeStatus_OutOfMemory = 2,       // Arena alloc failed
  kUpb_DecodeStatus_BadUtf8 = 3,           // String field had bad UTF-8
  kUpb_DecodeStatus_MaxDepthExceeded = 4,  // Exceeded UPB_DECODE_MAXDEPTH

  // kUpb_DecodeOption_CheckRequired failed (see above), but the parse otherwise
  // succeeded.
  kUpb_DecodeStatus_MissingRequired = 5,
} upb_DecodeStatus;

upb_DecodeStatus upb_Decode(const char* buf, size_t size, upb_Message* msg,
                            const upb_MiniTable* l,
                            const upb_ExtensionRegistry* extreg, int options,
                            upb_Arena* arena);

#ifdef __cplusplus
} /* extern "C" */
#endif

#include "upb/port_undef.inc"

#endif /* UPB_DECODE_H_ */