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 // Defines an implementation of Message which can emulate types which are not 36 // known at compile-time. 37 38 #ifndef GOOGLE_PROTOBUF_DYNAMIC_MESSAGE_H__ 39 #define GOOGLE_PROTOBUF_DYNAMIC_MESSAGE_H__ 40 41 #include <algorithm> 42 #include <memory> 43 #include <unordered_map> 44 #include <vector> 45 46 #include <google/protobuf/stubs/common.h> 47 #include <google/protobuf/message.h> 48 #include <google/protobuf/stubs/mutex.h> 49 #include <google/protobuf/reflection.h> 50 #include <google/protobuf/repeated_field.h> 51 52 #ifdef SWIG 53 #error "You cannot SWIG proto headers" 54 #endif 55 56 #include <google/protobuf/port_def.inc> 57 58 namespace google { 59 namespace protobuf { 60 61 // Defined in other files. 62 class Descriptor; // descriptor.h 63 class DescriptorPool; // descriptor.h 64 65 // Constructs implementations of Message which can emulate types which are not 66 // known at compile-time. 67 // 68 // Sometimes you want to be able to manipulate protocol types that you don't 69 // know about at compile time. It would be nice to be able to construct 70 // a Message object which implements the message type given by any arbitrary 71 // Descriptor. DynamicMessage provides this. 72 // 73 // As it turns out, a DynamicMessage needs to construct extra 74 // information about its type in order to operate. Most of this information 75 // can be shared between all DynamicMessages of the same type. But, caching 76 // this information in some sort of global map would be a bad idea, since 77 // the cached information for a particular descriptor could outlive the 78 // descriptor itself. To avoid this problem, DynamicMessageFactory 79 // encapsulates this "cache". All DynamicMessages of the same type created 80 // from the same factory will share the same support data. Any Descriptors 81 // used with a particular factory must outlive the factory. 82 class PROTOBUF_EXPORT DynamicMessageFactory : public MessageFactory { 83 public: 84 // Construct a DynamicMessageFactory that will search for extensions in 85 // the DescriptorPool in which the extendee is defined. 86 DynamicMessageFactory(); 87 88 // Construct a DynamicMessageFactory that will search for extensions in 89 // the given DescriptorPool. 90 // 91 // DEPRECATED: Use CodedInputStream::SetExtensionRegistry() to tell the 92 // parser to look for extensions in an alternate pool. However, note that 93 // this is almost never what you want to do. Almost all users should use 94 // the zero-arg constructor. 95 DynamicMessageFactory(const DescriptorPool* pool); 96 97 ~DynamicMessageFactory(); 98 99 // Call this to tell the DynamicMessageFactory that if it is given a 100 // Descriptor d for which: 101 // d->file()->pool() == DescriptorPool::generated_pool(), 102 // then it should delegate to MessageFactory::generated_factory() instead 103 // of constructing a dynamic implementation of the message. In theory there 104 // is no down side to doing this, so it may become the default in the future. SetDelegateToGeneratedFactory(bool enable)105 void SetDelegateToGeneratedFactory(bool enable) { 106 delegate_to_generated_factory_ = enable; 107 } 108 109 // implements MessageFactory --------------------------------------- 110 111 // Given a Descriptor, constructs the default (prototype) Message of that 112 // type. You can then call that message's New() method to construct a 113 // mutable message of that type. 114 // 115 // Calling this method twice with the same Descriptor returns the same 116 // object. The returned object remains property of the factory and will 117 // be destroyed when the factory is destroyed. Also, any objects created 118 // by calling the prototype's New() method share some data with the 119 // prototype, so these must be destroyed before the DynamicMessageFactory 120 // is destroyed. 121 // 122 // The given descriptor must outlive the returned message, and hence must 123 // outlive the DynamicMessageFactory. 124 // 125 // The method is thread-safe. 126 const Message* GetPrototype(const Descriptor* type) override; 127 128 private: 129 const DescriptorPool* pool_; 130 bool delegate_to_generated_factory_; 131 132 struct TypeInfo; 133 std::unordered_map<const Descriptor*, const TypeInfo*> prototypes_; 134 mutable internal::WrappedMutex prototypes_mutex_; 135 136 friend class DynamicMessage; 137 const Message* GetPrototypeNoLock(const Descriptor* type); 138 139 GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(DynamicMessageFactory); 140 }; 141 142 // Helper for computing a sorted list of map entries via reflection. 143 class PROTOBUF_EXPORT DynamicMapSorter { 144 public: Sort(const Message & message,int map_size,const Reflection * reflection,const FieldDescriptor * field)145 static std::vector<const Message*> Sort(const Message& message, int map_size, 146 const Reflection* reflection, 147 const FieldDescriptor* field) { 148 std::vector<const Message*> result; 149 result.reserve(map_size); 150 RepeatedFieldRef<Message> map_field = 151 reflection->GetRepeatedFieldRef<Message>(message, field); 152 for (auto it = map_field.begin(); it != map_field.end(); ++it) { 153 result.push_back(&*it); 154 } 155 MapEntryMessageComparator comparator(field->message_type()); 156 std::stable_sort(result.begin(), result.end(), comparator); 157 // Complain if the keys aren't in ascending order. 158 #ifndef NDEBUG 159 for (size_t j = 1; j < static_cast<size_t>(map_size); j++) { 160 if (!comparator(result[j - 1], result[j])) { 161 GOOGLE_LOG(ERROR) << (comparator(result[j], result[j - 1]) 162 ? "internal error in map key sorting" 163 : "map keys are not unique"); 164 } 165 } 166 #endif 167 return result; 168 } 169 170 private: 171 class PROTOBUF_EXPORT MapEntryMessageComparator { 172 public: MapEntryMessageComparator(const Descriptor * descriptor)173 explicit MapEntryMessageComparator(const Descriptor* descriptor) 174 : field_(descriptor->field(0)) {} 175 operator()176 bool operator()(const Message* a, const Message* b) { 177 const Reflection* reflection = a->GetReflection(); 178 switch (field_->cpp_type()) { 179 case FieldDescriptor::CPPTYPE_BOOL: { 180 bool first = reflection->GetBool(*a, field_); 181 bool second = reflection->GetBool(*b, field_); 182 return first < second; 183 } 184 case FieldDescriptor::CPPTYPE_INT32: { 185 int32 first = reflection->GetInt32(*a, field_); 186 int32 second = reflection->GetInt32(*b, field_); 187 return first < second; 188 } 189 case FieldDescriptor::CPPTYPE_INT64: { 190 int64 first = reflection->GetInt64(*a, field_); 191 int64 second = reflection->GetInt64(*b, field_); 192 return first < second; 193 } 194 case FieldDescriptor::CPPTYPE_UINT32: { 195 uint32 first = reflection->GetUInt32(*a, field_); 196 uint32 second = reflection->GetUInt32(*b, field_); 197 return first < second; 198 } 199 case FieldDescriptor::CPPTYPE_UINT64: { 200 uint64 first = reflection->GetUInt64(*a, field_); 201 uint64 second = reflection->GetUInt64(*b, field_); 202 return first < second; 203 } 204 case FieldDescriptor::CPPTYPE_STRING: { 205 std::string first = reflection->GetString(*a, field_); 206 std::string second = reflection->GetString(*b, field_); 207 return first < second; 208 } 209 default: 210 GOOGLE_LOG(DFATAL) << "Invalid key for map field."; 211 return true; 212 } 213 } 214 215 private: 216 const FieldDescriptor* field_; 217 }; 218 }; 219 220 } // namespace protobuf 221 } // namespace google 222 223 #include <google/protobuf/port_undef.inc> 224 225 #endif // GOOGLE_PROTOBUF_DYNAMIC_MESSAGE_H__ 226