1 // Protocol Buffers - Google's data interchange format 2 // Copyright 2023 Google LLC. All rights reserved. 3 // 4 // Use of this source code is governed by a BSD-style 5 // license that can be found in the LICENSE file or at 6 // https://developers.google.com/open-source/licenses/bsd 7 8 #ifndef UPB_MINI_TABLE_TAGGED_PTR_H_ 9 #define UPB_MINI_TABLE_TAGGED_PTR_H_ 10 11 #include <stdint.h> 12 13 #include "upb/message/internal/tagged_ptr.h" 14 #include "upb/message/message.h" 15 16 // Must be last. 17 #include "upb/port/def.inc" 18 19 // When a upb_Message* is stored in a message, array, or map, it is stored in a 20 // tagged form. If the tag bit is set, the referenced upb_Message is of type 21 // _kUpb_MiniTable_Empty (a sentinel message type with no fields) instead of 22 // that field's true message type. This forms the basis of what we call 23 // "dynamic tree shaking." 24 // 25 // See the documentation for kUpb_DecodeOption_ExperimentalAllowUnlinked for 26 // more information. 27 28 typedef uintptr_t upb_TaggedMessagePtr; 29 30 #ifdef __cplusplus 31 extern "C" { 32 #endif 33 34 // Users who enable unlinked sub-messages must use this to test whether a 35 // message is empty before accessing it. If a message is empty, it must be 36 // first promoted using the interfaces in message/promote.h. upb_TaggedMessagePtr_IsEmpty(upb_TaggedMessagePtr ptr)37UPB_INLINE bool upb_TaggedMessagePtr_IsEmpty(upb_TaggedMessagePtr ptr) { 38 return UPB_PRIVATE(_upb_TaggedMessagePtr_IsEmpty)(ptr); 39 } 40 upb_TaggedMessagePtr_GetNonEmptyMessage(upb_TaggedMessagePtr ptr)41UPB_INLINE upb_Message* upb_TaggedMessagePtr_GetNonEmptyMessage( 42 upb_TaggedMessagePtr ptr) { 43 return UPB_PRIVATE(_upb_TaggedMessagePtr_GetNonEmptyMessage)(ptr); 44 } 45 46 #ifdef __cplusplus 47 } /* extern "C" */ 48 #endif 49 50 #include "upb/port/undef.inc" 51 52 #endif /* UPB_MINI_TABLE_TAGGED_PTR_H_ */ 53