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_MESSAGE_INTERNAL_EXTENSION_H_ 9 #define UPB_MESSAGE_INTERNAL_EXTENSION_H_ 10 11 #include <stddef.h> 12 13 #include "upb/mem/arena.h" 14 #include "upb/message/value.h" 15 #include "upb/mini_table/extension.h" 16 17 // Must be last. 18 #include "upb/port/def.inc" 19 20 // The internal representation of an extension is self-describing: it contains 21 // enough information that we can serialize it to binary format without needing 22 // to look it up in a upb_ExtensionRegistry. 23 // 24 // This representation allocates 16 bytes to data on 64-bit platforms. 25 // This is rather wasteful for scalars (in the extreme case of bool, 26 // it wastes 15 bytes). We accept this because we expect messages to be 27 // the most common extension type. 28 typedef struct { 29 const upb_MiniTableExtension* ext; 30 upb_MessageValue data; 31 } upb_Extension; 32 33 #ifdef __cplusplus 34 extern "C" { 35 #endif 36 37 // Adds the given extension data to the given message. 38 // |ext| is copied into the message instance. 39 // This logically replaces any previously-added extension with this number. 40 upb_Extension* UPB_PRIVATE(_upb_Message_GetOrCreateExtension)( 41 struct upb_Message* msg, const upb_MiniTableExtension* ext, 42 upb_Arena* arena); 43 44 // Returns an array of extensions for this message. 45 // Note: the array is ordered in reverse relative to the order of creation. 46 const upb_Extension* UPB_PRIVATE(_upb_Message_Getexts)( 47 const struct upb_Message* msg, size_t* count); 48 49 // Returns an extension for a message with a given mini table, 50 // or NULL if no extension exists with this mini table. 51 const upb_Extension* UPB_PRIVATE(_upb_Message_Getext)( 52 const struct upb_Message* msg, const upb_MiniTableExtension* ext); 53 54 #ifdef __cplusplus 55 } /* extern "C" */ 56 #endif 57 58 #include "upb/port/undef.inc" 59 60 #endif /* UPB_MESSAGE_INTERNAL_EXTENSION_H_ */ 61