diff options
Diffstat (limited to 'src/google/protobuf/message.h')
| -rw-r--r-- | src/google/protobuf/message.h | 692 |
1 files changed, 692 insertions, 0 deletions
diff --git a/src/google/protobuf/message.h b/src/google/protobuf/message.h new file mode 100644 index 0000000..54b596d --- /dev/null +++ b/src/google/protobuf/message.h @@ -0,0 +1,692 @@ +// Protocol Buffers - Google's data interchange format +// Copyright 2008 Google Inc. All rights reserved. +// http://code.google.com/p/protobuf/ +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are +// met: +// +// * Redistributions of source code must retain the above copyright +// 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. +// * Neither the name of Google Inc. nor the names of its +// 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 +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// 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 Message, the abstract interface implemented by non-lite +// protocol message objects. Although it's possible to implement this +// interface manually, most users will use the protocol compiler to +// generate implementations. +// +// Example usage: +// +// Say you have a message defined as: +// +// message Foo { +// optional string text = 1; +// repeated int32 numbers = 2; +// } +// +// Then, if you used the protocol compiler to generate a class from the above +// definition, you could use it like so: +// +// string data; // Will store a serialized version of the message. +// +// { +// // Create a message and serialize it. +// Foo foo; +// foo.set_text("Hello World!"); +// foo.add_numbers(1); +// foo.add_numbers(5); +// foo.add_numbers(42); +// +// foo.SerializeToString(&data); +// } +// +// { +// // Parse the serialized message and check that it contains the +// // correct data. +// Foo foo; +// foo.ParseFromString(data); +// +// assert(foo.text() == "Hello World!"); +// assert(foo.numbers_size() == 3); +// assert(foo.numbers(0) == 1); +// assert(foo.numbers(1) == 5); +// assert(foo.numbers(2) == 42); +// } +// +// { +// // Same as the last block, but do it dynamically via the Message +// // reflection interface. +// Message* foo = new Foo; +// Descriptor* descriptor = foo->GetDescriptor(); +// +// // Get the descriptors for the fields we're interested in and verify +// // their types. +// FieldDescriptor* text_field = descriptor->FindFieldByName("text"); +// assert(text_field != NULL); +// assert(text_field->type() == FieldDescriptor::TYPE_STRING); +// assert(text_field->label() == FieldDescriptor::TYPE_OPTIONAL); +// FieldDescriptor* numbers_field = descriptor->FindFieldByName("numbers"); +// assert(numbers_field != NULL); +// assert(numbers_field->type() == FieldDescriptor::TYPE_INT32); +// assert(numbers_field->label() == FieldDescriptor::TYPE_REPEATED); +// +// // Parse the message. +// foo->ParseFromString(data); +// +// // Use the reflection interface to examine the contents. +// const Reflection* reflection = foo->GetReflection(); +// assert(reflection->GetString(foo, text_field) == "Hello World!"); +// assert(reflection->FieldSize(foo, numbers_field) == 3); +// assert(reflection->GetRepeatedInt32(foo, numbers_field, 0) == 1); +// assert(reflection->GetRepeatedInt32(foo, numbers_field, 1) == 5); +// assert(reflection->GetRepeatedInt32(foo, numbers_field, 2) == 42); +// +// delete foo; +// } + +#ifndef GOOGLE_PROTOBUF_MESSAGE_H__ +#define GOOGLE_PROTOBUF_MESSAGE_H__ + +#include <vector> +#include <string> + +#ifdef __DECCXX +// HP C++'s iosfwd doesn't work. +#include <iostream> +#else +#include <iosfwd> +#endif + +#include <google/protobuf/message_lite.h> + +#include <google/protobuf/stubs/common.h> + +#if defined(_WIN32) && defined(GetMessage) +// windows.h defines GetMessage() as a macro. Let's re-define it as an inline +// function. This is necessary because Reflection has a method called +// GetMessage() which we don't want overridden. The inline function should be +// equivalent for C++ users. +inline BOOL GetMessage_Win32( + LPMSG lpMsg, HWND hWnd, + UINT wMsgFilterMin, UINT wMsgFilterMax) { + return GetMessage(lpMsg, hWnd, wMsgFilterMin, wMsgFilterMax); +} +#undef GetMessage +inline BOOL GetMessage( + LPMSG lpMsg, HWND hWnd, + UINT wMsgFilterMin, UINT wMsgFilterMax) { + return GetMessage_Win32(lpMsg, hWnd, wMsgFilterMin, wMsgFilterMax); +} +#endif + + +namespace google { +namespace protobuf { + +// Defined in this file. +class Message; +class Reflection; + +// Defined in other files. +class Descriptor; // descriptor.h +class FieldDescriptor; // descriptor.h +class EnumDescriptor; // descriptor.h +class EnumValueDescriptor; // descriptor.h +namespace io { + class ZeroCopyInputStream; // zero_copy_stream.h + class ZeroCopyOutputStream; // zero_copy_stream.h + class CodedInputStream; // coded_stream.h + class CodedOutputStream; // coded_stream.h +} +class UnknownFieldSet; // unknown_field_set.h + +// A container to hold message metadata. +struct Metadata { + const Descriptor* descriptor; + const Reflection* reflection; +}; + +// Returns the EnumDescriptor for enum type E, which must be a +// proto-declared enum type. Code generated by the protocol compiler +// will include specializations of this template for each enum type declared. +template <typename E> +const EnumDescriptor* GetEnumDescriptor(); + +// Abstract interface for protocol messages. +// +// See also MessageLite, which contains most every-day operations. Message +// adds descriptors and reflection on top of that. +// +// The methods of this class that are virtual but not pure-virtual have +// default implementations based on reflection. Message classes which are +// optimized for speed will want to override these with faster implementations, +// but classes optimized for code size may be happy with keeping them. See +// the optimize_for option in descriptor.proto. +class LIBPROTOBUF_EXPORT Message : public MessageLite { + public: + inline Message() {} + virtual ~Message(); + + // Basic Operations ------------------------------------------------ + + // Construct a new instance of the same type. Ownership is passed to the + // caller. (This is also defined in MessageLite, but is defined again here + // for return-type covariance.) + virtual Message* New() const = 0; + + // Make this message into a copy of the given message. The given message + // must have the same descriptor, but need not necessarily be the same class. + // By default this is just implemented as "Clear(); MergeFrom(from);". + virtual void CopyFrom(const Message& from); + + // Merge the fields from the given message into this message. Singular + // fields will be overwritten, except for embedded messages which will + // be merged. Repeated fields will be concatenated. The given message + // must be of the same type as this message (i.e. the exact same class). + virtual void MergeFrom(const Message& from); + + // Verifies that IsInitialized() returns true. GOOGLE_CHECK-fails otherwise, with + // a nice error message. + void CheckInitialized() const; + + // Slowly build a list of all required fields that are not set. + // This is much, much slower than IsInitialized() as it is implemented + // purely via reflection. Generally, you should not call this unless you + // have already determined that an error exists by calling IsInitialized(). + void FindInitializationErrors(vector<string>* errors) const; + + // Like FindInitializationErrors, but joins all the strings, delimited by + // commas, and returns them. + string InitializationErrorString() const; + + // Clears all unknown fields from this message and all embedded messages. + // Normally, if unknown tag numbers are encountered when parsing a message, + // the tag and value are stored in the message's UnknownFieldSet and + // then written back out when the message is serialized. This allows servers + // which simply route messages to other servers to pass through messages + // that have new field definitions which they don't yet know about. However, + // this behavior can have security implications. To avoid it, call this + // method after parsing. + // + // See Reflection::GetUnknownFields() for more on unknown fields. + virtual void DiscardUnknownFields(); + + // Computes (an estimate of) the total number of bytes currently used for + // storing the message in memory. The default implementation calls the + // Reflection object's SpaceUsed() method. + virtual int SpaceUsed() const; + + // Debugging ------------------------------------------------------- + + // Generates a human readable form of this message, useful for debugging + // and other purposes. + string DebugString() const; + // Like DebugString(), but with less whitespace. + string ShortDebugString() const; + // Convenience function useful in GDB. Prints DebugString() to stdout. + void PrintDebugString() const; + + // Heavy I/O ------------------------------------------------------- + // Additional parsing and serialization methods not implemented by + // MessageLite because they are not supported by the lite library. + + // Parse a protocol buffer from a file descriptor. If successful, the entire + // input will be consumed. + bool ParseFromFileDescriptor(int file_descriptor); + // Like ParseFromFileDescriptor(), but accepts messages that are missing + // required fields. + bool ParsePartialFromFileDescriptor(int file_descriptor); + // Parse a protocol buffer from a C++ istream. If successful, the entire + // input will be consumed. + bool ParseFromIstream(istream* input); + // Like ParseFromIstream(), but accepts messages that are missing + // required fields. + bool ParsePartialFromIstream(istream* input); + + // Serialize the message and write it to the given file descriptor. All + // required fields must be set. + bool SerializeToFileDescriptor(int file_descriptor) const; + // Like SerializeToFileDescriptor(), but allows missing required fields. + bool SerializePartialToFileDescriptor(int file_descriptor) const; + // Serialize the message and write it to the given C++ ostream. All + // required fields must be set. + bool SerializeToOstream(ostream* output) const; + // Like SerializeToOstream(), but allows missing required fields. + bool SerializePartialToOstream(ostream* output) const; + + + // Reflection-based methods ---------------------------------------- + // These methods are pure-virtual in MessageLite, but Message provides + // reflection-based default implementations. + + virtual string GetTypeName() const; + virtual void Clear(); + virtual bool IsInitialized() const; + virtual void CheckTypeAndMergeFrom(const MessageLite& other); + virtual bool MergePartialFromCodedStream(io::CodedInputStream* input); + virtual int ByteSize() const; + virtual void SerializeWithCachedSizes(io::CodedOutputStream* output) const; + + private: + // This is called only by the default implementation of ByteSize(), to + // update the cached size. If you override ByteSize(), you do not need + // to override this. If you do not override ByteSize(), you MUST override + // this; the default implementation will crash. + // + // The method is private because subclasses should never call it; only + // override it. Yes, C++ lets you do that. Crazy, huh? + virtual void SetCachedSize(int size) const; + + public: + + // Introspection --------------------------------------------------- + + // Typedef for backwards-compatibility. + typedef google::protobuf::Reflection Reflection; + + // Get a Descriptor for this message's type. This describes what + // fields the message contains, the types of those fields, etc. + const Descriptor* GetDescriptor() const { return GetMetadata().descriptor; } + + // Get the Reflection interface for this Message, which can be used to + // read and modify the fields of the Message dynamically (in other words, + // without knowing the message type at compile time). This object remains + // property of the Message. + // + // This method remains virtual in case a subclass does not implement + // reflection and wants to override the default behavior. + virtual const Reflection* GetReflection() const { + return GetMetadata().reflection; + } + + protected: + // Get a struct containing the metadata for the Message. Most subclasses only + // need to implement this method, rather than the GetDescriptor() and + // GetReflection() wrappers. + virtual Metadata GetMetadata() const = 0; + + private: + GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(Message); +}; + +// This interface contains methods that can be used to dynamically access +// and modify the fields of a protocol message. Their semantics are +// similar to the accessors the protocol compiler generates. +// +// To get the Reflection for a given Message, call Message::GetReflection(). +// +// This interface is separate from Message only for efficiency reasons; +// the vast majority of implementations of Message will share the same +// implementation of Reflection (GeneratedMessageReflection, +// defined in generated_message.h), and all Messages of a particular class +// should share the same Reflection object (though you should not rely on +// the latter fact). +// +// There are several ways that these methods can be used incorrectly. For +// example, any of the following conditions will lead to undefined +// results (probably assertion failures): +// - The FieldDescriptor is not a field of this message type. +// - The method called is not appropriate for the field's type. For +// each field type in FieldDescriptor::TYPE_*, there is only one +// Get*() method, one Set*() method, and one Add*() method that is +// valid for that type. It should be obvious which (except maybe +// for TYPE_BYTES, which are represented using strings in C++). +// - A Get*() or Set*() method for singular fields is called on a repeated +// field. +// - GetRepeated*(), SetRepeated*(), or Add*() is called on a non-repeated +// field. +// - The Message object passed to any method is not of the right type for +// this Reflection object (i.e. message.GetReflection() != reflection). +// +// You might wonder why there is not any abstract representation for a field +// of arbitrary type. E.g., why isn't there just a "GetField()" method that +// returns "const Field&", where "Field" is some class with accessors like +// "GetInt32Value()". The problem is that someone would have to deal with +// allocating these Field objects. For generated message classes, having to +// allocate space for an additional object to wrap every field would at least +// double the message's memory footprint, probably worse. Allocating the +// objects on-demand, on the other hand, would be expensive and prone to +// memory leaks. So, instead we ended up with this flat interface. +// +// TODO(kenton): Create a utility class which callers can use to read and +// write fields from a Reflection without paying attention to the type. +class LIBPROTOBUF_EXPORT Reflection { + public: + // TODO(kenton): Remove parameter. + inline Reflection() {} + virtual ~Reflection(); + + // Get the UnknownFieldSet for the message. This contains fields which + // were seen when the Message was parsed but were not recognized according + // to the Message's definition. + virtual const UnknownFieldSet& GetUnknownFields( + const Message& message) const = 0; + // Get a mutable pointer to the UnknownFieldSet for the message. This + // contains fields which were seen when the Message was parsed but were not + // recognized according to the Message's definition. + virtual UnknownFieldSet* MutableUnknownFields(Message* message) const = 0; + + // Estimate the amount of memory used by the message object. + virtual int SpaceUsed(const Message& message) const = 0; + + // Check if the given non-repeated field is set. + virtual bool HasField(const Message& message, + const FieldDescriptor* field) const = 0; + + // Get the number of elements of a repeated field. + virtual int FieldSize(const Message& message, + const FieldDescriptor* field) const = 0; + + // Clear the value of a field, so that HasField() returns false or + // FieldSize() returns zero. + virtual void ClearField(Message* message, + const FieldDescriptor* field) const = 0; + + // Remove the last element of a repeated field. + // We don't provide a way to remove any element other than the last + // because it invites inefficient use, such as O(n^2) filtering loops + // that should have been O(n). If you want to remove an element other + // than the last, the best way to do it is to re-arrange the elements + // (using Swap()) so that the one you want removed is at the end, then + // call RemoveLast(). + virtual void RemoveLast(Message* message, + const FieldDescriptor* field) const = 0; + + // Swap the complete contents of two messages. + virtual void Swap(Message* message1, Message* message2) const = 0; + + // Swap two elements of a repeated field. + virtual void SwapElements(Message* message, + const FieldDescriptor* field, + int index1, + int index2) const = 0; + + // List all fields of the message which are currently set. This includes + // extensions. Singular fields will only be listed if HasField(field) would + // return true and repeated fields will only be listed if FieldSize(field) + // would return non-zero. Fields (both normal fields and extension fields) + // will be listed ordered by field number. + virtual void ListFields(const Message& message, + vector<const FieldDescriptor*>* output) const = 0; + + // Singular field getters ------------------------------------------ + // These get the value of a non-repeated field. They return the default + // value for fields that aren't set. + + virtual int32 GetInt32 (const Message& message, + const FieldDescriptor* field) const = 0; + virtual int64 GetInt64 (const Message& message, + const FieldDescriptor* field) const = 0; + virtual uint32 GetUInt32(const Message& message, + const FieldDescriptor* field) const = 0; + virtual uint64 GetUInt64(const Message& message, + const FieldDescriptor* field) const = 0; + virtual float GetFloat (const Message& message, + const FieldDescriptor* field) const = 0; + virtual double GetDouble(const Message& message, + const FieldDescriptor* field) const = 0; + virtual bool GetBool (const Message& message, + const FieldDescriptor* field) const = 0; + virtual string GetString(const Message& message, + const FieldDescriptor* field) const = 0; + virtual const EnumValueDescriptor* GetEnum( + const Message& message, const FieldDescriptor* field) const = 0; + virtual const Message& GetMessage(const Message& message, + const FieldDescriptor* field) const = 0; + + // Get a string value without copying, if possible. + // + // GetString() necessarily returns a copy of the string. This can be + // inefficient when the string is already stored in a string object in the + // underlying message. GetStringReference() will return a reference to the + // underlying string in this case. Otherwise, it will copy the string into + // *scratch and return that. + // + // Note: It is perfectly reasonable and useful to write code like: + // str = reflection->GetStringReference(field, &str); + // This line would ensure that only one copy of the string is made + // regardless of the field's underlying representation. When initializing + // a newly-constructed string, though, it's just as fast and more readable + // to use code like: + // string str = reflection->GetString(field); + virtual const string& GetStringReference(const Message& message, + const FieldDescriptor* field, + string* scratch) const = 0; + + + // Singular field mutators ----------------------------------------- + // These mutate the value of a non-repeated field. + + virtual void SetInt32 (Message* message, + const FieldDescriptor* field, int32 value) const = 0; + virtual void SetInt64 (Message* message, + const FieldDescriptor* field, int64 value) const = 0; + virtual void SetUInt32(Message* message, + const FieldDescriptor* field, uint32 value) const = 0; + virtual void SetUInt64(Message* message, + const FieldDescriptor* field, uint64 value) const = 0; + virtual void SetFloat (Message* message, + const FieldDescriptor* field, float value) const = 0; + virtual void SetDouble(Message* message, + const FieldDescriptor* field, double value) const = 0; + virtual void SetBool (Message* message, + const FieldDescriptor* field, bool value) const = 0; + virtual void SetString(Message* message, + const FieldDescriptor* field, + const string& value) const = 0; + virtual void SetEnum (Message* message, + const FieldDescriptor* field, + const EnumValueDescriptor* value) const = 0; + // Get a mutable pointer to a field with a message type. + virtual Message* MutableMessage(Message* message, + const FieldDescriptor* field) const = 0; + + + // Repeated field getters ------------------------------------------ + // These get the value of one element of a repeated field. + + virtual int32 GetRepeatedInt32 (const Message& message, + const FieldDescriptor* field, + int index) const = 0; + virtual int64 GetRepeatedInt64 (const Message& message, + const FieldDescriptor* field, + int index) const = 0; + virtual uint32 GetRepeatedUInt32(const Message& message, + const FieldDescriptor* field, + int index) const = 0; + virtual uint64 GetRepeatedUInt64(const Message& message, + const FieldDescriptor* field, + int index) const = 0; + virtual float GetRepeatedFloat (const Message& message, + const FieldDescriptor* field, + int index) const = 0; + virtual double GetRepeatedDouble(const Message& message, + const FieldDescriptor* field, + int index) const = 0; + virtual bool GetRepeatedBool (const Message& message, + const FieldDescriptor* field, + int index) const = 0; + virtual string GetRepeatedString(const Message& message, + const FieldDescriptor* field, + int index) const = 0; + virtual const EnumValueDescriptor* GetRepeatedEnum( + const Message& message, + const FieldDescriptor* field, int index) const = 0; + virtual const Message& GetRepeatedMessage( + const Message& message, + const FieldDescriptor* field, int index) const = 0; + + // See GetStringReference(), above. + virtual const string& GetRepeatedStringReference( + const Message& message, const FieldDescriptor* field, + int index, string* scratch) const = 0; + + + // Repeated field mutators ----------------------------------------- + // These mutate the value of one element of a repeated field. + + virtual void SetRepeatedInt32 (Message* message, + const FieldDescriptor* field, + int index, int32 value) const = 0; + virtual void SetRepeatedInt64 (Message* message, + const FieldDescriptor* field, + int index, int64 value) const = 0; + virtual void SetRepeatedUInt32(Message* message, + const FieldDescriptor* field, + int index, uint32 value) const = 0; + virtual void SetRepeatedUInt64(Message* message, + const FieldDescriptor* field, + int index, uint64 value) const = 0; + virtual void SetRepeatedFloat (Message* message, + const FieldDescriptor* field, + int index, float value) const = 0; + virtual void SetRepeatedDouble(Message* message, + const FieldDescriptor* field, + int index, double value) const = 0; + virtual void SetRepeatedBool (Message* message, + const FieldDescriptor* field, + int index, bool value) const = 0; + virtual void SetRepeatedString(Message* message, + const FieldDescriptor* field, + int index, const string& value) const = 0; + virtual void SetRepeatedEnum(Message* message, + const FieldDescriptor* field, int index, + const EnumValueDescriptor* value) const = 0; + // Get a mutable pointer to an element of a repeated field with a message + // type. + virtual Message* MutableRepeatedMessage( + Message* message, const FieldDescriptor* field, int index) const = 0; + + + // Repeated field adders ------------------------------------------- + // These add an element to a repeated field. + + virtual void AddInt32 (Message* message, + const FieldDescriptor* field, int32 value) const = 0; + virtual void AddInt64 (Message* message, + const FieldDescriptor* field, int64 value) const = 0; + virtual void AddUInt32(Message* message, + const FieldDescriptor* field, uint32 value) const = 0; + virtual void AddUInt64(Message* message, + const FieldDescriptor* field, uint64 value) const = 0; + virtual void AddFloat (Message* message, + const FieldDescriptor* field, float value) const = 0; + virtual void AddDouble(Message* message, + const FieldDescriptor* field, double value) const = 0; + virtual void AddBool (Message* message, + const FieldDescriptor* field, bool value) const = 0; + virtual void AddString(Message* message, + const FieldDescriptor* field, + const string& value) const = 0; + virtual void AddEnum (Message* message, + const FieldDescriptor* field, + const EnumValueDescriptor* value) const = 0; + virtual Message* AddMessage(Message* message, + const FieldDescriptor* field) const = 0; + + + // Extensions ------------------------------------------------------ + + // Try to find an extension of this message type by fully-qualified field + // name. Returns NULL if no extension is known for this name or number. + virtual const FieldDescriptor* FindKnownExtensionByName( + const string& name) const = 0; + + // Try to find an extension of this message type by field number. + // Returns NULL if no extension is known for this name or number. + virtual const FieldDescriptor* FindKnownExtensionByNumber( + int number) const = 0; + + private: + GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(Reflection); +}; + +// Abstract interface for a factory for message objects. +class LIBPROTOBUF_EXPORT MessageFactory { + public: + inline MessageFactory() {} + virtual ~MessageFactory(); + + // Given a Descriptor, gets or 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. Also, any + // objects created by calling the prototype's New() method share some data + // with the prototype, so these must be destoyed before the MessageFactory + // is destroyed. + // + // The given descriptor must outlive the returned message, and hence must + // outlive the MessageFactory. + // + // Some implementations do not support all types. GetPrototype() will + // return NULL if the descriptor passed in is not supported. + // + // This method may or may not be thread-safe depending on the implementation. + // Each implementation should document its own degree thread-safety. + virtual const Message* GetPrototype(const Descriptor* type) = 0; + + // Gets a MessageFactory which supports all generated, compiled-in messages. + // In other words, for any compiled-in type FooMessage, the following is true: + // MessageFactory::generated_factory()->GetPrototype( + // FooMessage::descriptor()) == FooMessage::default_instance() + // This factory supports all types which are found in + // DescriptorPool::generated_pool(). If given a descriptor from any other + // pool, GetPrototype() will return NULL. (You can also check if a + // descriptor is for a generated message by checking if + // descriptor->file()->pool() == DescriptorPool::generated_pool().) + // + // This factory is 100% thread-safe; calling GetPrototype() does not modify + // any shared data. + // + // This factory is a singleton. The caller must not delete the object. + static MessageFactory* generated_factory(); + + // For internal use only: Registers a .proto file at static initialization + // time, to be placed in generated_factory. The first time GetPrototype() + // is called with a descriptor from this file, |register_messages| will be + // called, with the file name as the parameter. It must call + // InternalRegisterGeneratedMessage() (below) to register each message type + // in the file. This strange mechanism is necessary because descriptors are + // built lazily, so we can't register types by their descriptor until we + // know that the descriptor exists. |filename| must be a permanent string. + static void InternalRegisterGeneratedFile( + const char* filename, void (*register_messages)(const string&)); + + // For internal use only: Registers a message type. Called only by the + // functions which are registered with InternalRegisterGeneratedFile(), + // above. + static void InternalRegisterGeneratedMessage(const Descriptor* descriptor, + const Message* prototype); + + private: + GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(MessageFactory); +}; + +} // namespace protobuf + +} // namespace google +#endif // GOOGLE_PROTOBUF_MESSAGE_H__ |