| // Protocol Buffers - Google's data interchange format |
| // Copyright 2008 Google Inc. All rights reserved. |
| // https://developers.google.com/protocol-buffers/ |
| // |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are |
| // met: |
| // |
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| // notice, this list of conditions and the following disclaimer. |
| // * Redistributions in binary form must reproduce the above |
| // copyright notice, this list of conditions and the following disclaimer |
| // in the documentation and/or other materials provided with the |
| // distribution. |
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| // contributors may be used to endorse or promote products derived from |
| // this software without specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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| // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| // Author: kenton@google.com (Kenton Varda) |
| // Based on original Protocol Buffers design by |
| // Sanjay Ghemawat, Jeff Dean, and others. |
| // |
| // Defines an implementation of Message which can emulate types which are not |
| // known at compile-time. |
| |
| #ifndef GOOGLE_PROTOBUF_DYNAMIC_MESSAGE_H__ |
| #define GOOGLE_PROTOBUF_DYNAMIC_MESSAGE_H__ |
| |
| #include <memory> |
| #ifndef _SHARED_PTR_H |
| #include <google/protobuf/stubs/shared_ptr.h> |
| #endif |
| |
| #include <google/protobuf/message.h> |
| #include <google/protobuf/stubs/common.h> |
| |
| namespace google { |
| namespace protobuf { |
| |
| // Defined in other files. |
| class Descriptor; // descriptor.h |
| class DescriptorPool; // descriptor.h |
| |
| // Constructs implementations of Message which can emulate types which are not |
| // known at compile-time. |
| // |
| // Sometimes you want to be able to manipulate protocol types that you don't |
| // know about at compile time. It would be nice to be able to construct |
| // a Message object which implements the message type given by any arbitrary |
| // Descriptor. DynamicMessage provides this. |
| // |
| // As it turns out, a DynamicMessage needs to construct extra |
| // information about its type in order to operate. Most of this information |
| // can be shared between all DynamicMessages of the same type. But, caching |
| // this information in some sort of global map would be a bad idea, since |
| // the cached information for a particular descriptor could outlive the |
| // descriptor itself. To avoid this problem, DynamicMessageFactory |
| // encapsulates this "cache". All DynamicMessages of the same type created |
| // from the same factory will share the same support data. Any Descriptors |
| // used with a particular factory must outlive the factory. |
| class LIBPROTOBUF_EXPORT DynamicMessageFactory : public MessageFactory { |
| public: |
| // Construct a DynamicMessageFactory that will search for extensions in |
| // the DescriptorPool in which the extendee is defined. |
| DynamicMessageFactory(); |
| |
| // Construct a DynamicMessageFactory that will search for extensions in |
| // the given DescriptorPool. |
| // |
| // DEPRECATED: Use CodedInputStream::SetExtensionRegistry() to tell the |
| // parser to look for extensions in an alternate pool. However, note that |
| // this is almost never what you want to do. Almost all users should use |
| // the zero-arg constructor. |
| DynamicMessageFactory(const DescriptorPool* pool); |
| |
| ~DynamicMessageFactory(); |
| |
| // Call this to tell the DynamicMessageFactory that if it is given a |
| // Descriptor d for which: |
| // d->file()->pool() == DescriptorPool::generated_pool(), |
| // then it should delegate to MessageFactory::generated_factory() instead |
| // of constructing a dynamic implementation of the message. In theory there |
| // is no down side to doing this, so it may become the default in the future. |
| void SetDelegateToGeneratedFactory(bool enable) { |
| delegate_to_generated_factory_ = enable; |
| } |
| |
| // implements MessageFactory --------------------------------------- |
| |
| // Given a Descriptor, constructs the default (prototype) Message of that |
| // type. You can then call that message's New() method to construct a |
| // mutable message of that type. |
| // |
| // Calling this method twice with the same Descriptor returns the same |
| // object. The returned object remains property of the factory and will |
| // be destroyed when the factory is destroyed. Also, any objects created |
| // by calling the prototype's New() method share some data with the |
| // prototype, so these must be destroyed before the DynamicMessageFactory |
| // is destroyed. |
| // |
| // The given descriptor must outlive the returned message, and hence must |
| // outlive the DynamicMessageFactory. |
| // |
| // The method is thread-safe. |
| const Message* GetPrototype(const Descriptor* type); |
| |
| private: |
| const DescriptorPool* pool_; |
| bool delegate_to_generated_factory_; |
| |
| // This struct just contains a hash_map. We can't #include <google/protobuf/stubs/hash.h> from |
| // this header due to hacks needed for hash_map portability in the open source |
| // release. Namely, stubs/hash.h, which defines hash_map portably, is not a |
| // public header (for good reason), but dynamic_message.h is, and public |
| // headers may only #include other public headers. |
| struct PrototypeMap; |
| google::protobuf::scoped_ptr<PrototypeMap> prototypes_; |
| mutable Mutex prototypes_mutex_; |
| |
| friend class DynamicMessage; |
| const Message* GetPrototypeNoLock(const Descriptor* type); |
| |
| // Construct default oneof instance for reflection usage if oneof |
| // is defined. |
| static void ConstructDefaultOneofInstance(const Descriptor* type, |
| const int offsets[], |
| void* default_oneof_instance); |
| // Delete default oneof instance. Called by ~DynamicMessageFactory. |
| static void DeleteDefaultOneofInstance(const Descriptor* type, |
| const int offsets[], |
| void* default_oneof_instance); |
| |
| GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(DynamicMessageFactory); |
| }; |
| |
| } // namespace protobuf |
| |
| } // namespace google |
| #endif // GOOGLE_PROTOBUF_DYNAMIC_MESSAGE_H__ |