1 // Protocol Buffers - Google's data interchange format 2 // Copyright 2008 Google Inc. All rights reserved. 3 // https://developers.google.com/protocol-buffers/ 4 // 5 // Redistribution and use in source and binary forms, with or without 6 // modification, are permitted provided that the following conditions are 7 // met: 8 // 9 // * Redistributions of source code must retain the above copyright 10 // notice, this list of conditions and the following disclaimer. 11 // * Redistributions in binary form must reproduce the above 12 // copyright notice, this list of conditions and the following disclaimer 13 // in the documentation and/or other materials provided with the 14 // distribution. 15 // * Neither the name of Google Inc. nor the names of its 16 // contributors may be used to endorse or promote products derived from 17 // this software without specific prior written permission. 18 // 19 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 20 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 21 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 22 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 23 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 24 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 25 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 26 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 27 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 28 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 29 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 30 31 // Author: kenton@google.com (Kenton Varda) 32 // Based on original Protocol Buffers design by 33 // Sanjay Ghemawat, Jeff Dean, and others. 34 // 35 // This header is logically internal, but is made public because it is used 36 // from protocol-compiler-generated code, which may reside in other components. 37 38 #ifndef GOOGLE_PROTOBUF_GENERATED_MESSAGE_REFLECTION_H__ 39 #define GOOGLE_PROTOBUF_GENERATED_MESSAGE_REFLECTION_H__ 40 41 #include <string> 42 #include <vector> 43 #include <google/protobuf/stubs/casts.h> 44 #include <google/protobuf/stubs/common.h> 45 // TODO(jasonh): Remove this once the compiler change to directly include this 46 // is released to components. 47 #include <google/protobuf/descriptor.h> 48 #include <google/protobuf/generated_enum_reflection.h> 49 #include <google/protobuf/stubs/once.h> 50 #include <google/protobuf/port.h> 51 #include <google/protobuf/unknown_field_set.h> 52 53 54 #include <google/protobuf/port_def.inc> 55 56 #ifdef SWIG 57 #error "You cannot SWIG proto headers" 58 #endif 59 60 namespace google { 61 namespace protobuf { 62 class DescriptorPool; 63 class MapKey; 64 class MapValueRef; 65 class MessageLayoutInspector; 66 class Message; 67 struct Metadata; 68 } // namespace protobuf 69 } // namespace google 70 71 namespace google { 72 namespace protobuf { 73 namespace internal { 74 class DefaultEmptyOneof; 75 // Defined in other files. 76 class ExtensionSet; // extension_set.h 77 class WeakFieldMap; // weak_field_map.h 78 79 // This struct describes the internal layout of the message, hence this is 80 // used to act on the message reflectively. 81 // default_instance: The default instance of the message. This is only 82 // used to obtain pointers to default instances of embedded 83 // messages, which GetMessage() will return if the particular 84 // sub-message has not been initialized yet. (Thus, all 85 // embedded message fields *must* have non-null pointers 86 // in the default instance.) 87 // offsets: An array of ints giving the byte offsets. 88 // For each oneof or weak field, the offset is relative to the 89 // default_instance. These can be computed at compile time 90 // using the 91 // PROTO2_GENERATED_DEFAULT_ONEOF_FIELD_OFFSET() 92 // macro. For each none oneof field, the offset is related to 93 // the start of the message object. These can be computed at 94 // compile time using the 95 // PROTO2_GENERATED_MESSAGE_FIELD_OFFSET() macro. 96 // Besides offsets for all fields, this array also contains 97 // offsets for oneof unions. The offset of the i-th oneof union 98 // is offsets[descriptor->field_count() + i]. 99 // has_bit_indices: Mapping from field indexes to their index in the has 100 // bit array. 101 // has_bits_offset: Offset in the message of an array of uint32s of size 102 // descriptor->field_count()/32, rounded up. This is a 103 // bitfield where each bit indicates whether or not the 104 // corresponding field of the message has been initialized. 105 // The bit for field index i is obtained by the expression: 106 // has_bits[i / 32] & (1 << (i % 32)) 107 // unknown_fields_offset: Offset in the message of the UnknownFieldSet for 108 // the message. 109 // extensions_offset: Offset in the message of the ExtensionSet for the 110 // message, or -1 if the message type has no extension 111 // ranges. 112 // oneof_case_offset: Offset in the message of an array of uint32s of 113 // size descriptor->oneof_decl_count(). Each uint32 114 // indicates what field is set for each oneof. 115 // object_size: The size of a message object of this type, as measured 116 // by sizeof(). 117 // arena_offset: If a message doesn't have a unknown_field_set that stores 118 // the arena, it must have a direct pointer to the arena. 119 // weak_field_map_offset: If the message proto has weak fields, this is the 120 // offset of _weak_field_map_ in the generated proto. Otherwise 121 // -1. 122 struct ReflectionSchema { 123 public: 124 // Size of a google::protobuf::Message object of this type. GetObjectSizeReflectionSchema125 uint32 GetObjectSize() const { return static_cast<uint32>(object_size_); } 126 InRealOneofReflectionSchema127 bool InRealOneof(const FieldDescriptor* field) const { 128 return field->containing_oneof() && 129 !field->containing_oneof()->is_synthetic(); 130 } 131 132 // Offset of a non-oneof field. Getting a field offset is slightly more 133 // efficient when we know statically that it is not a oneof field. GetFieldOffsetNonOneofReflectionSchema134 uint32 GetFieldOffsetNonOneof(const FieldDescriptor* field) const { 135 GOOGLE_DCHECK(!InRealOneof(field)); 136 return OffsetValue(offsets_[field->index()], field->type()); 137 } 138 139 // Offset of any field. GetFieldOffsetReflectionSchema140 uint32 GetFieldOffset(const FieldDescriptor* field) const { 141 if (InRealOneof(field)) { 142 size_t offset = 143 static_cast<size_t>(field->containing_type()->field_count() + 144 field->containing_oneof()->index()); 145 return OffsetValue(offsets_[offset], field->type()); 146 } else { 147 return GetFieldOffsetNonOneof(field); 148 } 149 } 150 IsFieldInlinedReflectionSchema151 bool IsFieldInlined(const FieldDescriptor* field) const { 152 if (InRealOneof(field)) { 153 size_t offset = 154 static_cast<size_t>(field->containing_type()->field_count() + 155 field->containing_oneof()->index()); 156 return Inlined(offsets_[offset], field->type()); 157 } else { 158 return Inlined(offsets_[field->index()], field->type()); 159 } 160 } 161 GetOneofCaseOffsetReflectionSchema162 uint32 GetOneofCaseOffset(const OneofDescriptor* oneof_descriptor) const { 163 return static_cast<uint32>(oneof_case_offset_) + 164 static_cast<uint32>(static_cast<size_t>(oneof_descriptor->index()) * 165 sizeof(uint32)); 166 } 167 HasHasbitsReflectionSchema168 bool HasHasbits() const { return has_bits_offset_ != -1; } 169 170 // Bit index within the bit array of hasbits. Bit order is low-to-high. HasBitIndexReflectionSchema171 uint32 HasBitIndex(const FieldDescriptor* field) const { 172 if (has_bits_offset_ == -1) return static_cast<uint32>(-1); 173 GOOGLE_DCHECK(HasHasbits()); 174 return has_bit_indices_[field->index()]; 175 } 176 177 // Byte offset of the hasbits array. HasBitsOffsetReflectionSchema178 uint32 HasBitsOffset() const { 179 GOOGLE_DCHECK(HasHasbits()); 180 return static_cast<uint32>(has_bits_offset_); 181 } 182 183 // The offset of the InternalMetadataWithArena member. 184 // For Lite this will actually be an InternalMetadataWithArenaLite. 185 // The schema doesn't contain enough information to distinguish between 186 // these two cases. GetMetadataOffsetReflectionSchema187 uint32 GetMetadataOffset() const { 188 return static_cast<uint32>(metadata_offset_); 189 } 190 191 // Whether this message has an ExtensionSet. HasExtensionSetReflectionSchema192 bool HasExtensionSet() const { return extensions_offset_ != -1; } 193 194 // The offset of the ExtensionSet in this message. GetExtensionSetOffsetReflectionSchema195 uint32 GetExtensionSetOffset() const { 196 GOOGLE_DCHECK(HasExtensionSet()); 197 return static_cast<uint32>(extensions_offset_); 198 } 199 200 // The off set of WeakFieldMap when the message contains weak fields. 201 // The default is 0 for now. GetWeakFieldMapOffsetReflectionSchema202 int GetWeakFieldMapOffset() const { return weak_field_map_offset_; } 203 IsDefaultInstanceReflectionSchema204 bool IsDefaultInstance(const Message& message) const { 205 return &message == default_instance_; 206 } 207 208 // Returns a pointer to the default value for this field. The size and type 209 // of the underlying data depends on the field's type. GetFieldDefaultReflectionSchema210 const void* GetFieldDefault(const FieldDescriptor* field) const { 211 return reinterpret_cast<const uint8*>(default_instance_) + 212 OffsetValue(offsets_[field->index()], field->type()); 213 } 214 IsFieldStrippedReflectionSchema215 bool IsFieldStripped(const FieldDescriptor* field) const { 216 return false; 217 } 218 IsMessageStrippedReflectionSchema219 bool IsMessageStripped(const Descriptor* descriptor) const { 220 return false; 221 } 222 223 HasWeakFieldsReflectionSchema224 bool HasWeakFields() const { return weak_field_map_offset_ > 0; } 225 226 // These members are intended to be private, but we cannot actually make them 227 // private because this prevents us from using aggregate initialization of 228 // them, ie. 229 // 230 // ReflectionSchema schema = {a, b, c, d, e, ...}; 231 // private: 232 const Message* default_instance_; 233 const uint32* offsets_; 234 const uint32* has_bit_indices_; 235 int has_bits_offset_; 236 int metadata_offset_; 237 int extensions_offset_; 238 int oneof_case_offset_; 239 int object_size_; 240 int weak_field_map_offset_; 241 242 // We tag offset values to provide additional data about fields (such as 243 // inlined). OffsetValueReflectionSchema244 static uint32 OffsetValue(uint32 v, FieldDescriptor::Type type) { 245 if (type == FieldDescriptor::TYPE_STRING || 246 type == FieldDescriptor::TYPE_BYTES) { 247 return v & ~1u; 248 } else { 249 return v; 250 } 251 } 252 InlinedReflectionSchema253 static bool Inlined(uint32 v, FieldDescriptor::Type type) { 254 if (type == FieldDescriptor::TYPE_STRING || 255 type == FieldDescriptor::TYPE_BYTES) { 256 return v & 1u; 257 } else { 258 // Non string/byte fields are not inlined. 259 return false; 260 } 261 } 262 }; 263 264 // Structs that the code generator emits directly to describe a message. 265 // These should never used directly except to build a ReflectionSchema 266 // object. 267 // 268 // EXPERIMENTAL: these are changing rapidly, and may completely disappear 269 // or merge with ReflectionSchema. 270 struct MigrationSchema { 271 int32 offsets_index; 272 int32 has_bit_indices_index; 273 int object_size; 274 }; 275 276 struct SCCInfoBase; 277 278 struct PROTOBUF_EXPORT DescriptorTable { 279 mutable bool is_initialized; 280 bool is_eager; 281 const char* descriptor; 282 const char* filename; 283 int size; // of serialized descriptor 284 once_flag* once; 285 SCCInfoBase* const* init_default_instances; 286 const DescriptorTable* const* deps; 287 int num_sccs; 288 int num_deps; 289 const MigrationSchema* schemas; 290 const Message* const* default_instances; 291 const uint32* offsets; 292 // update the following descriptor arrays. 293 Metadata* file_level_metadata; 294 int num_messages; 295 const EnumDescriptor** file_level_enum_descriptors; 296 const ServiceDescriptor** file_level_service_descriptors; 297 }; 298 299 // AssignDescriptors() pulls the compiled FileDescriptor from the DescriptorPool 300 // and uses it to populate all of the global variables which store pointers to 301 // the descriptor objects. It also constructs the reflection objects. It is 302 // called the first time anyone calls descriptor() or GetReflection() on one of 303 // the types defined in the file. AssignDescriptors() is thread-safe. 304 void PROTOBUF_EXPORT AssignDescriptors(const DescriptorTable* table, 305 bool eager = false); 306 307 // AddDescriptors() is a file-level procedure which adds the encoded 308 // FileDescriptorProto for this .proto file to the global DescriptorPool for 309 // generated files (DescriptorPool::generated_pool()). It ordinarily runs at 310 // static initialization time, but is not used at all in LITE_RUNTIME mode. 311 // AddDescriptors() is *not* thread-safe. 312 void PROTOBUF_EXPORT AddDescriptors(const DescriptorTable* table); 313 314 // These cannot be in lite so we put them in the reflection. 315 PROTOBUF_EXPORT void UnknownFieldSetSerializer(const uint8* base, uint32 offset, 316 uint32 tag, uint32 has_offset, 317 io::CodedOutputStream* output); 318 319 } // namespace internal 320 } // namespace protobuf 321 } // namespace google 322 323 #include <google/protobuf/port_undef.inc> 324 325 #endif // GOOGLE_PROTOBUF_GENERATED_MESSAGE_REFLECTION_H__ 326