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0001 // Protocol Buffers - Google's data interchange format 0002 // Copyright 2023 Google LLC. All rights reserved. 0003 // 0004 // Use of this source code is governed by a BSD-style 0005 // license that can be found in the LICENSE file or at 0006 // https://developers.google.com/open-source/licenses/bsd 0007 0008 // upb_decode: parsing into a upb_Message using a upb_MiniTable. 0009 0010 #ifndef UPB_WIRE_DECODE_H_ 0011 #define UPB_WIRE_DECODE_H_ 0012 0013 #include <stddef.h> 0014 #include <stdint.h> 0015 0016 #include "upb/mem/arena.h" 0017 #include "upb/message/message.h" 0018 #include "upb/mini_table/extension_registry.h" 0019 #include "upb/mini_table/message.h" 0020 0021 // Must be last. 0022 #include "upb/port/def.inc" 0023 0024 #ifdef __cplusplus 0025 extern "C" { 0026 #endif 0027 0028 enum { 0029 /* If set, strings will alias the input buffer instead of copying into the 0030 * arena. */ 0031 kUpb_DecodeOption_AliasString = 1, 0032 0033 /* If set, the parse will return failure if any message is missing any 0034 * required fields when the message data ends. The parse will still continue, 0035 * and the failure will only be reported at the end. 0036 * 0037 * IMPORTANT CAVEATS: 0038 * 0039 * 1. This can throw a false positive failure if an incomplete message is seen 0040 * on the wire but is later completed when the sub-message occurs again. 0041 * For this reason, a second pass is required to verify a failure, to be 0042 * truly robust. 0043 * 0044 * 2. This can return a false success if you are decoding into a message that 0045 * already has some sub-message fields present. If the sub-message does 0046 * not occur in the binary payload, we will never visit it and discover the 0047 * incomplete sub-message. For this reason, this check is only useful for 0048 * implemting ParseFromString() semantics. For MergeFromString(), a 0049 * post-parse validation step will always be necessary. */ 0050 kUpb_DecodeOption_CheckRequired = 2, 0051 0052 /* EXPERIMENTAL: 0053 * 0054 * If set, the parser will allow parsing of sub-message fields that were not 0055 * previously linked using upb_MiniTable_SetSubMessage(). The data will be 0056 * parsed into an internal "empty" message type that cannot be accessed 0057 * directly, but can be later promoted into the true message type if the 0058 * sub-message fields are linked at a later time. 0059 * 0060 * Users should set this option if they intend to perform dynamic tree shaking 0061 * and promoting using the interfaces in message/promote.h. If this option is 0062 * enabled, it is important that the resulting messages are only accessed by 0063 * code that is aware of promotion rules: 0064 * 0065 * 1. Message pointers in upb_Message, upb_Array, and upb_Map are represented 0066 * by a tagged pointer upb_TaggedMessagePointer. The tag indicates whether 0067 * the message uses the internal "empty" type. 0068 * 0069 * 2. Any code *reading* these message pointers must test whether the "empty" 0070 * tag bit is set, using the interfaces in mini_table/types.h. However 0071 * writing of message pointers should always use plain upb_Message*, since 0072 * users are not allowed to create "empty" messages. 0073 * 0074 * 3. It is always safe to test whether a field is present or test the array 0075 * length; these interfaces will reflect that empty messages are present, 0076 * even though their data cannot be accessed without promoting first. 0077 * 0078 * 4. If a message pointer is indeed tagged as empty, the message may not be 0079 * accessed directly, only promoted through the interfaces in 0080 * message/promote.h. 0081 * 0082 * 5. Tagged/empty messages may never be created by the user. They may only 0083 * be created by the parser or the message-copying logic in message/copy.h. 0084 */ 0085 kUpb_DecodeOption_ExperimentalAllowUnlinked = 4, 0086 0087 /* EXPERIMENTAL: 0088 * 0089 * If set, decoding will enforce UTF-8 validation for string fields, even for 0090 * proto2 or fields with `features.utf8_validation = NONE`. Normally, only 0091 * proto3 string fields will be validated for UTF-8. Decoding will return 0092 * kUpb_DecodeStatus_BadUtf8 for non-UTF-8 strings, which is the same behavior 0093 * as non-UTF-8 proto3 string fields. 0094 */ 0095 kUpb_DecodeOption_AlwaysValidateUtf8 = 8, 0096 }; 0097 0098 UPB_INLINE uint32_t upb_DecodeOptions_MaxDepth(uint16_t depth) { 0099 return (uint32_t)depth << 16; 0100 } 0101 0102 UPB_INLINE uint16_t upb_DecodeOptions_GetMaxDepth(uint32_t options) { 0103 return options >> 16; 0104 } 0105 0106 // Enforce an upper bound on recursion depth. 0107 UPB_INLINE int upb_Decode_LimitDepth(uint32_t decode_options, uint32_t limit) { 0108 uint32_t max_depth = upb_DecodeOptions_GetMaxDepth(decode_options); 0109 if (max_depth > limit) max_depth = limit; 0110 return upb_DecodeOptions_MaxDepth(max_depth) | (decode_options & 0xffff); 0111 } 0112 0113 // LINT.IfChange 0114 typedef enum { 0115 kUpb_DecodeStatus_Ok = 0, 0116 kUpb_DecodeStatus_Malformed = 1, // Wire format was corrupt 0117 kUpb_DecodeStatus_OutOfMemory = 2, // Arena alloc failed 0118 kUpb_DecodeStatus_BadUtf8 = 3, // String field had bad UTF-8 0119 kUpb_DecodeStatus_MaxDepthExceeded = 0120 4, // Exceeded upb_DecodeOptions_MaxDepth 0121 0122 // kUpb_DecodeOption_CheckRequired failed (see above), but the parse otherwise 0123 // succeeded. 0124 kUpb_DecodeStatus_MissingRequired = 5, 0125 0126 // Unlinked sub-message field was present, but 0127 // kUpb_DecodeOptions_ExperimentalAllowUnlinked was not specified in the list 0128 // of options. 0129 kUpb_DecodeStatus_UnlinkedSubMessage = 6, 0130 } upb_DecodeStatus; 0131 // LINT.ThenChange(//depot/google3/third_party/protobuf/rust/upb.rs:decode_status) 0132 0133 UPB_API upb_DecodeStatus upb_Decode(const char* buf, size_t size, 0134 upb_Message* msg, const upb_MiniTable* mt, 0135 const upb_ExtensionRegistry* extreg, 0136 int options, upb_Arena* arena); 0137 0138 // Same as upb_Decode but with a varint-encoded length prepended. 0139 // On success 'num_bytes_read' will be set to the how many bytes were read, 0140 // on failure the contents of num_bytes_read is undefined. 0141 UPB_API upb_DecodeStatus upb_DecodeLengthPrefixed( 0142 const char* buf, size_t size, upb_Message* msg, size_t* num_bytes_read, 0143 const upb_MiniTable* mt, const upb_ExtensionRegistry* extreg, int options, 0144 upb_Arena* arena); 0145 0146 // Utility function for wrapper languages to get an error string from a 0147 // upb_DecodeStatus. 0148 UPB_API const char* upb_DecodeStatus_String(upb_DecodeStatus status); 0149 #ifdef __cplusplus 0150 } /* extern "C" */ 0151 #endif 0152 0153 #include "upb/port/undef.inc" 0154 0155 #endif /* UPB_WIRE_DECODE_H_ */
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