标题:[Protobuf] (1)快速上手
@水墨不写bug
一、什么是protobuf?
Protocol Buffers(简称 protobuf)是由 Google 开发的一种与语言无关、平台无关、可扩展的序列化数据结构的方法。它用于结构化数据的序列化与反序列化,类似于 XML 或 JSON,但更小、更快、更简单。
二、protobuf的特点
protobuf 可以把数据结构(比如对象或消息)编码成紧凑的二进制格式,之后再还原回原始的数据结构。 这阐明protobuf编码是比较安全的,由于二进制无法被直接阅读。
其他重要特点:
- 跨语言(支持 Java、C++、Python、Go、C#、JavaScript 等多种语言)
- 二进制格式,高效且体积小
- 向后兼容和向前兼容性好(得当长期演进的体系)
- 需要提前定义数据结构(.proto 文件)
减少开发周期和负担
protobuf可以通过protoc编译器来编译proto文件来生成对应的头文件和源文件,内部已经实现了序列化和反序列化的接口。- - - 节省开发时间,制止重复性造轮子
三、使用protobuf的过程?
1、定义消息格式(.proto文件)
(1)指定语法版本
创建**.proto**文件后,首行需要先指定protobuf的语法版本,假如不指定,默认使用proto2。一般我们都使用proto3。 - - - proto3的语法更加简便,支持更多的语言(比如C#)
(2)package 声明符
在proto文件编译之后,假如写了pageage声明,那么cc和h文件内部会被定名空间封装。
假如没有package声明,则cc和h文件的对应类不会被定名空间包裹。
2、使用protoc编译器生成代码
经过1、2两步,后,就可以编写消息的内部数据结构了,假如如下设计(文件名称为 “contact.proto” ):
- //首行:语法指定行
- syntax = "proto3";
- //package 声明符
- package contast;
- //定义联系人信息
- message PersonInfo
- {
- string name = 1;
- int32 age = 2;
- }
复制代码 下一步就需要编译:
(1)当前目录直接编译:
- protoc --cpp_out=. contact.proto
复制代码 这段指令的含义如下:
- protoc:表示 Protocol Buffers 的编译器程序(Protocol Compiler)。
- --cpp_out=.:指定生成 C++ 语言的代码文件,并将生成的文件输出到当前目录(. 代表当前目录)。
- contact.proto:需要被编译的 proto 文件,即你定义了消息结构的协议文件。
综合解释
这条命令的作用是:
使用 Protocol Buffers 的编译器 protoc,将 contact.proto 文件中定义的消息结构,自动生成对应的 C++ 源代码文件(通常为 contact.pb.h 和 contact.pb.cc),并把它们输出到当前目录下。
如许你就可以在 C++ 项目中直接包含和使用这些自动生成的代码了。
(2)指定目录编译
这种情况适用于当前没有处在contact.proto文件所在的目录时:
- protoc -I contact_dir/ --cpp_out=contact_dir/ contact.proto
复制代码 这段指令的含义如下:
- protoc
Protocol Buffers 的编译器(protocol compiler)。
- -I contact_dir/
指定包含 proto 文件的搜索目录(即 import 路径)。表示编译器在 contact_dir/ 目录下查找 proto 文件及其 import 的依赖。
- --cpp_out=contact_dir/
指定输出目录为 contact_dir/,并生成 C++ 源代码(通常为 .pb.h 和 .pb.cc 文件)。
- contact.proto
要编译的 proto 文件,定义了详细的数据结构。
综合解释:
这条命令会让 protoc 在 contact_dir/ 目录下查找 contact.proto,将其编译为 C++ 源代码,并把生成的 .pb.h 和 .pb.cc 文件输出到同样的 contact_dir/ 目录下。
这种写法常用于项目结构较复杂时,便于管理 proto 文件及生成的代码。
3、在业务中引入并使用生成的类
通过protoc编译proto文件之后,会生成下面两个文件:
- // Generated by the protocol buffer compiler. DO NOT EDIT!
- // NO CHECKED-IN PROTOBUF GENCODE
- // source: contact.proto
- // Protobuf C++ Version: 6.31.0
- #include "contact.pb.h"
- #include <algorithm>
- #include <type_traits>
- #include "google/protobuf/io/coded_stream.h"
- #include "google/protobuf/generated_message_tctable_impl.h"
- #include "google/protobuf/extension_set.h"
- #include "google/protobuf/generated_message_util.h"
- #include "google/protobuf/wire_format_lite.h"
- #include "google/protobuf/descriptor.h"
- #include "google/protobuf/generated_message_reflection.h"
- #include "google/protobuf/reflection_ops.h"
- #include "google/protobuf/wire_format.h"
- // @@protoc_insertion_point(includes)
- // Must be included last.
- #include "google/protobuf/port_def.inc"
- PROTOBUF_PRAGMA_INIT_SEG
- namespace _pb = ::google::protobuf;
- namespace _pbi = ::google::protobuf::internal;
- namespace _fl = ::google::protobuf::internal::field_layout;
- namespace contact {
- inline constexpr Info::Impl_::Impl_(
- ::_pbi::ConstantInitialized) noexcept
- : _cached_size_{0},
- name_(
- &::google::protobuf::internal::fixed_address_empty_string,
- ::_pbi::ConstantInitialized()),
- age_{0} {}
- template <typename>
- PROTOBUF_CONSTEXPR Info::Info(::_pbi::ConstantInitialized)
- #if defined(PROTOBUF_CUSTOM_VTABLE)
- : ::google::protobuf::Message(Info_class_data_.base()),
- #else // PROTOBUF_CUSTOM_VTABLE
- : ::google::protobuf::Message(),
- #endif // PROTOBUF_CUSTOM_VTABLE
- _impl_(::_pbi::ConstantInitialized()) {
- }
- struct InfoDefaultTypeInternal {
- PROTOBUF_CONSTEXPR InfoDefaultTypeInternal() : _instance(::_pbi::ConstantInitialized{}) {}
- ~InfoDefaultTypeInternal() {}
- union {
- Info _instance;
- };
- };
- PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT
- PROTOBUF_ATTRIBUTE_INIT_PRIORITY1 InfoDefaultTypeInternal _Info_default_instance_;
- } // namespace contact
- static constexpr const ::_pb::EnumDescriptor *PROTOBUF_NONNULL *PROTOBUF_NULLABLE
- file_level_enum_descriptors_contact_2eproto = nullptr;
- static constexpr const ::_pb::ServiceDescriptor *PROTOBUF_NONNULL *PROTOBUF_NULLABLE
- file_level_service_descriptors_contact_2eproto = nullptr;
- const ::uint32_t
- TableStruct_contact_2eproto::offsets[] ABSL_ATTRIBUTE_SECTION_VARIABLE(
- protodesc_cold) = {
- 0x081, // bitmap
- PROTOBUF_FIELD_OFFSET(::contact::Info, _impl_._has_bits_),
- 5, // hasbit index offset
- PROTOBUF_FIELD_OFFSET(::contact::Info, _impl_.name_),
- PROTOBUF_FIELD_OFFSET(::contact::Info, _impl_.age_),
- 0,
- 1,
- };
- static const ::_pbi::MigrationSchema
- schemas[] ABSL_ATTRIBUTE_SECTION_VARIABLE(protodesc_cold) = {
- {0, sizeof(::contact::Info)},
- };
- static const ::_pb::Message* PROTOBUF_NONNULL const file_default_instances[] = {
- &::contact::_Info_default_instance_._instance,
- };
- const char descriptor_table_protodef_contact_2eproto[] ABSL_ATTRIBUTE_SECTION_VARIABLE(
- protodesc_cold) = {
- "\n\rcontact.proto\022\007contact"!\n\004Info\022\014\n\004name"
- "\030\001 \001(\t\022\013\n\003age\030\002 \001(\005b\006proto3"
- };
- static ::absl::once_flag descriptor_table_contact_2eproto_once;
- PROTOBUF_CONSTINIT const ::_pbi::DescriptorTable descriptor_table_contact_2eproto = {
- false,
- false,
- 67,
- descriptor_table_protodef_contact_2eproto,
- "contact.proto",
- &descriptor_table_contact_2eproto_once,
- nullptr,
- 0,
- 1,
- schemas,
- file_default_instances,
- TableStruct_contact_2eproto::offsets,
- file_level_enum_descriptors_contact_2eproto,
- file_level_service_descriptors_contact_2eproto,
- };
- namespace contact {
- // ===================================================================
- class Info::_Internal {
- public:
- using HasBits =
- decltype(::std::declval<Info>()._impl_._has_bits_);
- static constexpr ::int32_t kHasBitsOffset =
- 8 * PROTOBUF_FIELD_OFFSET(Info, _impl_._has_bits_);
- };
- Info::Info(::google::protobuf::Arena* PROTOBUF_NULLABLE arena)
- #if defined(PROTOBUF_CUSTOM_VTABLE)
- : ::google::protobuf::Message(arena, Info_class_data_.base()) {
- #else // PROTOBUF_CUSTOM_VTABLE
- : ::google::protobuf::Message(arena) {
- #endif // PROTOBUF_CUSTOM_VTABLE
- SharedCtor(arena);
- // @@protoc_insertion_point(arena_constructor:contact.Info)
- }
- PROTOBUF_NDEBUG_INLINE Info::Impl_::Impl_(
- ::google::protobuf::internal::InternalVisibility visibility,
- ::google::protobuf::Arena* PROTOBUF_NULLABLE arena, const Impl_& from,
- const ::contact::Info& from_msg)
- : _has_bits_{from._has_bits_},
- _cached_size_{0},
- name_(arena, from.name_) {}
- Info::Info(
- ::google::protobuf::Arena* PROTOBUF_NULLABLE arena,
- const Info& from)
- #if defined(PROTOBUF_CUSTOM_VTABLE)
- : ::google::protobuf::Message(arena, Info_class_data_.base()) {
- #else // PROTOBUF_CUSTOM_VTABLE
- : ::google::protobuf::Message(arena) {
- #endif // PROTOBUF_CUSTOM_VTABLE
- Info* const _this = this;
- (void)_this;
- _internal_metadata_.MergeFrom<::google::protobuf::UnknownFieldSet>(
- from._internal_metadata_);
- new (&_impl_) Impl_(internal_visibility(), arena, from._impl_, from);
- _impl_.age_ = from._impl_.age_;
- // @@protoc_insertion_point(copy_constructor:contact.Info)
- }
- PROTOBUF_NDEBUG_INLINE Info::Impl_::Impl_(
- ::google::protobuf::internal::InternalVisibility visibility,
- ::google::protobuf::Arena* PROTOBUF_NULLABLE arena)
- : _cached_size_{0},
- name_(arena) {}
- inline void Info::SharedCtor(::_pb::Arena* PROTOBUF_NULLABLE arena) {
- new (&_impl_) Impl_(internal_visibility(), arena);
- _impl_.age_ = {};
- }
- Info::~Info() {
- // @@protoc_insertion_point(destructor:contact.Info)
- SharedDtor(*this);
- }
- inline void Info::SharedDtor(MessageLite& self) {
- Info& this_ = static_cast<Info&>(self);
- this_._internal_metadata_.Delete<::google::protobuf::UnknownFieldSet>();
- ABSL_DCHECK(this_.GetArena() == nullptr);
- this_._impl_.name_.Destroy();
- this_._impl_.~Impl_();
- }
- inline void* PROTOBUF_NONNULL Info::PlacementNew_(
- const void* PROTOBUF_NONNULL, void* PROTOBUF_NONNULL mem,
- ::google::protobuf::Arena* PROTOBUF_NULLABLE arena) {
- return ::new (mem) Info(arena);
- }
- constexpr auto Info::InternalNewImpl_() {
- return ::google::protobuf::internal::MessageCreator::CopyInit(sizeof(Info),
- alignof(Info));
- }
- constexpr auto Info::InternalGenerateClassData_() {
- return ::google::protobuf::internal::ClassDataFull{
- ::google::protobuf::internal::ClassData{
- &_Info_default_instance_._instance,
- &_table_.header,
- nullptr, // OnDemandRegisterArenaDtor
- nullptr, // IsInitialized
- &Info::MergeImpl,
- ::google::protobuf::Message::GetNewImpl<Info>(),
- #if defined(PROTOBUF_CUSTOM_VTABLE)
- &Info::SharedDtor,
- ::google::protobuf::Message::GetClearImpl<Info>(), &Info::ByteSizeLong,
- &Info::_InternalSerialize,
- #endif // PROTOBUF_CUSTOM_VTABLE
- PROTOBUF_FIELD_OFFSET(Info, _impl_._cached_size_),
- false,
- },
- &Info::kDescriptorMethods,
- &descriptor_table_contact_2eproto,
- nullptr, // tracker
- };
- }
- PROTOBUF_CONSTINIT PROTOBUF_ATTRIBUTE_INIT_PRIORITY1 const
- ::google::protobuf::internal::ClassDataFull Info_class_data_ =
- Info::InternalGenerateClassData_();
- PROTOBUF_ATTRIBUTE_WEAK const ::google::protobuf::internal::ClassData* PROTOBUF_NONNULL
- Info::GetClassData() const {
- ::google::protobuf::internal::PrefetchToLocalCache(&Info_class_data_);
- ::google::protobuf::internal::PrefetchToLocalCache(Info_class_data_.tc_table);
- return Info_class_data_.base();
- }
- PROTOBUF_CONSTINIT PROTOBUF_ATTRIBUTE_INIT_PRIORITY1
- const ::_pbi::TcParseTable<1, 2, 0, 25, 2>
- Info::_table_ = {
- {
- PROTOBUF_FIELD_OFFSET(Info, _impl_._has_bits_),
- 0, // no _extensions_
- 2, 8, // max_field_number, fast_idx_mask
- offsetof(decltype(_table_), field_lookup_table),
- 4294967292, // skipmap
- offsetof(decltype(_table_), field_entries),
- 2, // num_field_entries
- 0, // num_aux_entries
- offsetof(decltype(_table_), field_names), // no aux_entries
- Info_class_data_.base(),
- nullptr, // post_loop_handler
- ::_pbi::TcParser::GenericFallback, // fallback
- #ifdef PROTOBUF_PREFETCH_PARSE_TABLE
- ::_pbi::TcParser::GetTable<::contact::Info>(), // to_prefetch
- #endif // PROTOBUF_PREFETCH_PARSE_TABLE
- }, {{
- // int32 age = 2;
- {::_pbi::TcParser::SingularVarintNoZag1<::uint32_t, offsetof(Info, _impl_.age_), 1>(),
- {16, 1, 0, PROTOBUF_FIELD_OFFSET(Info, _impl_.age_)}},
- // string name = 1;
- {::_pbi::TcParser::FastUS1,
- {10, 0, 0, PROTOBUF_FIELD_OFFSET(Info, _impl_.name_)}},
- }}, {{
- 65535, 65535
- }}, {{
- // string name = 1;
- {PROTOBUF_FIELD_OFFSET(Info, _impl_.name_), _Internal::kHasBitsOffset + 0, 0,
- (0 | ::_fl::kFcOptional | ::_fl::kUtf8String | ::_fl::kRepAString)},
- // int32 age = 2;
- {PROTOBUF_FIELD_OFFSET(Info, _impl_.age_), _Internal::kHasBitsOffset + 1, 0,
- (0 | ::_fl::kFcOptional | ::_fl::kInt32)},
- }},
- // no aux_entries
- {{
- "\14\4\0\0\0\0\0\0"
- "contact.Info"
- "name"
- }},
- };
- PROTOBUF_NOINLINE void Info::Clear() {
- // @@protoc_insertion_point(message_clear_start:contact.Info)
- ::google::protobuf::internal::TSanWrite(&_impl_);
- ::uint32_t cached_has_bits = 0;
- // Prevent compiler warnings about cached_has_bits being unused
- (void) cached_has_bits;
- cached_has_bits = _impl_._has_bits_[0];
- if ((cached_has_bits & 0x00000001u) != 0) {
- _impl_.name_.ClearNonDefaultToEmpty();
- }
- _impl_.age_ = 0;
- _impl_._has_bits_.Clear();
- _internal_metadata_.Clear<::google::protobuf::UnknownFieldSet>();
- }
- #if defined(PROTOBUF_CUSTOM_VTABLE)
- ::uint8_t* PROTOBUF_NONNULL Info::_InternalSerialize(
- const ::google::protobuf::MessageLite& base, ::uint8_t* PROTOBUF_NONNULL target,
- ::google::protobuf::io::EpsCopyOutputStream* PROTOBUF_NONNULL stream) {
- const Info& this_ = static_cast<const Info&>(base);
- #else // PROTOBUF_CUSTOM_VTABLE
- ::uint8_t* PROTOBUF_NONNULL Info::_InternalSerialize(
- ::uint8_t* PROTOBUF_NONNULL target,
- ::google::protobuf::io::EpsCopyOutputStream* PROTOBUF_NONNULL stream) const {
- const Info& this_ = *this;
- #endif // PROTOBUF_CUSTOM_VTABLE
- // @@protoc_insertion_point(serialize_to_array_start:contact.Info)
- ::uint32_t cached_has_bits = 0;
- (void)cached_has_bits;
- // string name = 1;
- if ((this_._impl_._has_bits_[0] & 0x00000001u) != 0) {
- if (!this_._internal_name().empty()) {
- const ::std::string& _s = this_._internal_name();
- ::google::protobuf::internal::WireFormatLite::VerifyUtf8String(
- _s.data(), static_cast<int>(_s.length()), ::google::protobuf::internal::WireFormatLite::SERIALIZE, "contact.Info.name");
- target = stream->WriteStringMaybeAliased(1, _s, target);
- }
- }
- // int32 age = 2;
- if ((this_._impl_._has_bits_[0] & 0x00000002u) != 0) {
- if (this_._internal_age() != 0) {
- target =
- ::google::protobuf::internal::WireFormatLite::WriteInt32ToArrayWithField<2>(
- stream, this_._internal_age(), target);
- }
- }
- if (ABSL_PREDICT_FALSE(this_._internal_metadata_.have_unknown_fields())) {
- target =
- ::_pbi::WireFormat::InternalSerializeUnknownFieldsToArray(
- this_._internal_metadata_.unknown_fields<::google::protobuf::UnknownFieldSet>(::google::protobuf::UnknownFieldSet::default_instance), target, stream);
- }
- // @@protoc_insertion_point(serialize_to_array_end:contact.Info)
- return target;
- }
- #if defined(PROTOBUF_CUSTOM_VTABLE)
- ::size_t Info::ByteSizeLong(const MessageLite& base) {
- const Info& this_ = static_cast<const Info&>(base);
- #else // PROTOBUF_CUSTOM_VTABLE
- ::size_t Info::ByteSizeLong() const {
- const Info& this_ = *this;
- #endif // PROTOBUF_CUSTOM_VTABLE
- // @@protoc_insertion_point(message_byte_size_start:contact.Info)
- ::size_t total_size = 0;
- ::uint32_t cached_has_bits = 0;
- // Prevent compiler warnings about cached_has_bits being unused
- (void)cached_has_bits;
- ::_pbi::Prefetch5LinesFrom7Lines(&this_);
- cached_has_bits = this_._impl_._has_bits_[0];
- if ((cached_has_bits & 0x00000003u) != 0) {
- // string name = 1;
- if ((cached_has_bits & 0x00000001u) != 0) {
- if (!this_._internal_name().empty()) {
- total_size += 1 + ::google::protobuf::internal::WireFormatLite::StringSize(
- this_._internal_name());
- }
- }
- // int32 age = 2;
- if ((cached_has_bits & 0x00000002u) != 0) {
- if (this_._internal_age() != 0) {
- total_size += ::_pbi::WireFormatLite::Int32SizePlusOne(
- this_._internal_age());
- }
- }
- }
- return this_.MaybeComputeUnknownFieldsSize(total_size,
- &this_._impl_._cached_size_);
- }
- void Info::MergeImpl(::google::protobuf::MessageLite& to_msg, const ::google::protobuf::MessageLite& from_msg) {
- auto* const _this = static_cast<Info*>(&to_msg);
- auto& from = static_cast<const Info&>(from_msg);
- // @@protoc_insertion_point(class_specific_merge_from_start:contact.Info)
- ABSL_DCHECK_NE(&from, _this);
- ::uint32_t cached_has_bits = 0;
- (void) cached_has_bits;
- cached_has_bits = from._impl_._has_bits_[0];
- if ((cached_has_bits & 0x00000003u) != 0) {
- if ((cached_has_bits & 0x00000001u) != 0) {
- if (!from._internal_name().empty()) {
- _this->_internal_set_name(from._internal_name());
- } else {
- if (_this->_impl_.name_.IsDefault()) {
- _this->_internal_set_name("");
- }
- }
- }
- if ((cached_has_bits & 0x00000002u) != 0) {
- if (from._internal_age() != 0) {
- _this->_impl_.age_ = from._impl_.age_;
- }
- }
- }
- _this->_impl_._has_bits_[0] |= cached_has_bits;
- _this->_internal_metadata_.MergeFrom<::google::protobuf::UnknownFieldSet>(from._internal_metadata_);
- }
- void Info::CopyFrom(const Info& from) {
- // @@protoc_insertion_point(class_specific_copy_from_start:contact.Info)
- if (&from == this) return;
- Clear();
- MergeFrom(from);
- }
- void Info::InternalSwap(Info* PROTOBUF_RESTRICT PROTOBUF_NONNULL other) {
- using ::std::swap;
- auto* arena = GetArena();
- ABSL_DCHECK_EQ(arena, other->GetArena());
- _internal_metadata_.InternalSwap(&other->_internal_metadata_);
- swap(_impl_._has_bits_[0], other->_impl_._has_bits_[0]);
- ::_pbi::ArenaStringPtr::InternalSwap(&_impl_.name_, &other->_impl_.name_, arena);
- swap(_impl_.age_, other->_impl_.age_);
- }
- ::google::protobuf::Metadata Info::GetMetadata() const {
- return ::google::protobuf::Message::GetMetadataImpl(GetClassData()->full());
- }
- // @@protoc_insertion_point(namespace_scope)
- } // namespace contact
- namespace google {
- namespace protobuf {
- } // namespace protobuf
- } // namespace google
- // @@protoc_insertion_point(global_scope)
- PROTOBUF_ATTRIBUTE_INIT_PRIORITY2 static ::std::false_type
- _static_init2_ [[maybe_unused]] =
- (::_pbi::AddDescriptors(&descriptor_table_contact_2eproto),
- ::std::false_type{});
- #include "google/protobuf/port_undef.inc"
复制代码- // Generated by the protocol buffer compiler. DO NOT EDIT!
- // NO CHECKED-IN PROTOBUF GENCODE
- // source: contact.proto
- // Protobuf C++ Version: 6.31.0
- #ifndef contact_2eproto_2epb_2eh
- #define contact_2eproto_2epb_2eh
- #include <limits>
- #include <string>
- #include <type_traits>
- #include <utility>
- #include "google/protobuf/runtime_version.h"
- #if PROTOBUF_VERSION != 6031000
- #error "Protobuf C++ gencode is built with an incompatible version of"
- #error "Protobuf C++ headers/runtime. See"
- #error "https://protobuf.dev/support/cross-version-runtime-guarantee/#cpp"
- #endif
- #include "google/protobuf/io/coded_stream.h"
- #include "google/protobuf/arena.h"
- #include "google/protobuf/arenastring.h"
- #include "google/protobuf/generated_message_tctable_decl.h"
- #include "google/protobuf/generated_message_util.h"
- #include "google/protobuf/metadata_lite.h"
- #include "google/protobuf/generated_message_reflection.h"
- #include "google/protobuf/message.h"
- #include "google/protobuf/message_lite.h"
- #include "google/protobuf/repeated_field.h" // IWYU pragma: export
- #include "google/protobuf/extension_set.h" // IWYU pragma: export
- #include "google/protobuf/unknown_field_set.h"
- // @@protoc_insertion_point(includes)
- // Must be included last.
- #include "google/protobuf/port_def.inc"
- #define PROTOBUF_INTERNAL_EXPORT_contact_2eproto
- namespace google {
- namespace protobuf {
- namespace internal {
- template <typename T>
- ::absl::string_view GetAnyMessageName();
- } // namespace internal
- } // namespace protobuf
- } // namespace google
- // Internal implementation detail -- do not use these members.
- struct TableStruct_contact_2eproto {
- static const ::uint32_t offsets[];
- };
- extern "C" {
- extern const ::google::protobuf::internal::DescriptorTable descriptor_table_contact_2eproto;
- } // extern "C"
- namespace contact {
- class Info;
- struct InfoDefaultTypeInternal;
- extern InfoDefaultTypeInternal _Info_default_instance_;
- extern const ::google::protobuf::internal::ClassDataFull Info_class_data_;
- } // namespace contact
- namespace google {
- namespace protobuf {
- } // namespace protobuf
- } // namespace google
- namespace contact {
- // ===================================================================
- // -------------------------------------------------------------------
- class Info final : public ::google::protobuf::Message
- /* @@protoc_insertion_point(class_definition:contact.Info) */ {
- public:
- inline Info() : Info(nullptr) {}
- ~Info() PROTOBUF_FINAL;
- #if defined(PROTOBUF_CUSTOM_VTABLE)
- void operator delete(Info* PROTOBUF_NONNULL msg, std::destroying_delete_t) {
- SharedDtor(*msg);
- ::google::protobuf::internal::SizedDelete(msg, sizeof(Info));
- }
- #endif
- template <typename = void>
- explicit PROTOBUF_CONSTEXPR Info(::google::protobuf::internal::ConstantInitialized);
- inline Info(const Info& from) : Info(nullptr, from) {}
- inline Info(Info&& from) noexcept
- : Info(nullptr, ::std::move(from)) {}
- inline Info& operator=(const Info& from) {
- CopyFrom(from);
- return *this;
- }
- inline Info& operator=(Info&& from) noexcept {
- if (this == &from) return *this;
- if (::google::protobuf::internal::CanMoveWithInternalSwap(GetArena(), from.GetArena())) {
- InternalSwap(&from);
- } else {
- CopyFrom(from);
- }
- return *this;
- }
- inline const ::google::protobuf::UnknownFieldSet& unknown_fields() const
- ABSL_ATTRIBUTE_LIFETIME_BOUND {
- return _internal_metadata_.unknown_fields<::google::protobuf::UnknownFieldSet>(::google::protobuf::UnknownFieldSet::default_instance);
- }
- inline ::google::protobuf::UnknownFieldSet* PROTOBUF_NONNULL mutable_unknown_fields()
- ABSL_ATTRIBUTE_LIFETIME_BOUND {
- return _internal_metadata_.mutable_unknown_fields<::google::protobuf::UnknownFieldSet>();
- }
- static const ::google::protobuf::Descriptor* PROTOBUF_NONNULL descriptor() {
- return GetDescriptor();
- }
- static const ::google::protobuf::Descriptor* PROTOBUF_NONNULL GetDescriptor() {
- return default_instance().GetMetadata().descriptor;
- }
- static const ::google::protobuf::Reflection* PROTOBUF_NONNULL GetReflection() {
- return default_instance().GetMetadata().reflection;
- }
- static const Info& default_instance() {
- return *reinterpret_cast<const Info*>(
- &_Info_default_instance_);
- }
- static constexpr int kIndexInFileMessages = 0;
- friend void swap(Info& a, Info& b) { a.Swap(&b); }
- inline void Swap(Info* PROTOBUF_NONNULL other) {
- if (other == this) return;
- if (::google::protobuf::internal::CanUseInternalSwap(GetArena(), other->GetArena())) {
- InternalSwap(other);
- } else {
- ::google::protobuf::internal::GenericSwap(this, other);
- }
- }
- void UnsafeArenaSwap(Info* PROTOBUF_NONNULL other) {
- if (other == this) return;
- ABSL_DCHECK(GetArena() == other->GetArena());
- InternalSwap(other);
- }
- // implements Message ----------------------------------------------
- Info* PROTOBUF_NONNULL New(::google::protobuf::Arena* PROTOBUF_NULLABLE arena = nullptr) const {
- return ::google::protobuf::Message::DefaultConstruct<Info>(arena);
- }
- using ::google::protobuf::Message::CopyFrom;
- void CopyFrom(const Info& from);
- using ::google::protobuf::Message::MergeFrom;
- void MergeFrom(const Info& from) { Info::MergeImpl(*this, from); }
- private:
- static void MergeImpl(::google::protobuf::MessageLite& to_msg,
- const ::google::protobuf::MessageLite& from_msg);
- public:
- bool IsInitialized() const {
- return true;
- }
- ABSL_ATTRIBUTE_REINITIALIZES void Clear() PROTOBUF_FINAL;
- #if defined(PROTOBUF_CUSTOM_VTABLE)
- private:
- static ::size_t ByteSizeLong(const ::google::protobuf::MessageLite& msg);
- static ::uint8_t* PROTOBUF_NONNULL _InternalSerialize(
- const ::google::protobuf::MessageLite& msg, ::uint8_t* PROTOBUF_NONNULL target,
- ::google::protobuf::io::EpsCopyOutputStream* PROTOBUF_NONNULL stream);
- public:
- ::size_t ByteSizeLong() const { return ByteSizeLong(*this); }
- ::uint8_t* PROTOBUF_NONNULL _InternalSerialize(
- ::uint8_t* PROTOBUF_NONNULL target,
- ::google::protobuf::io::EpsCopyOutputStream* PROTOBUF_NONNULL stream) const {
- return _InternalSerialize(*this, target, stream);
- }
- #else // PROTOBUF_CUSTOM_VTABLE
- ::size_t ByteSizeLong() const final;
- ::uint8_t* PROTOBUF_NONNULL _InternalSerialize(
- ::uint8_t* PROTOBUF_NONNULL target,
- ::google::protobuf::io::EpsCopyOutputStream* PROTOBUF_NONNULL stream) const final;
- #endif // PROTOBUF_CUSTOM_VTABLE
- int GetCachedSize() const { return _impl_._cached_size_.Get(); }
- private:
- void SharedCtor(::google::protobuf::Arena* PROTOBUF_NULLABLE arena);
- static void SharedDtor(MessageLite& self);
- void InternalSwap(Info* PROTOBUF_NONNULL other);
- private:
- template <typename T>
- friend ::absl::string_view(::google::protobuf::internal::GetAnyMessageName)();
- static ::absl::string_view FullMessageName() { return "contact.Info"; }
- protected:
- explicit Info(::google::protobuf::Arena* PROTOBUF_NULLABLE arena);
- Info(::google::protobuf::Arena* PROTOBUF_NULLABLE arena, const Info& from);
- Info(
- ::google::protobuf::Arena* PROTOBUF_NULLABLE arena, Info&& from) noexcept
- : Info(arena) {
- *this = ::std::move(from);
- }
- const ::google::protobuf::internal::ClassData* PROTOBUF_NONNULL GetClassData() const PROTOBUF_FINAL;
- static void* PROTOBUF_NONNULL PlacementNew_(
- const void* PROTOBUF_NONNULL, void* PROTOBUF_NONNULL mem,
- ::google::protobuf::Arena* PROTOBUF_NULLABLE arena);
- static constexpr auto InternalNewImpl_();
- public:
- static constexpr auto InternalGenerateClassData_();
- ::google::protobuf::Metadata GetMetadata() const;
- // nested types ----------------------------------------------------
- // accessors -------------------------------------------------------
- enum : int {
- kNameFieldNumber = 1,
- kAgeFieldNumber = 2,
- };
- // string name = 1;
- void clear_name() ;
- const ::std::string& name() const;
- template <typename Arg_ = const ::std::string&, typename... Args_>
- void set_name(Arg_&& arg, Args_... args);
- ::std::string* PROTOBUF_NONNULL mutable_name();
- [[nodiscard]] ::std::string* PROTOBUF_NULLABLE release_name();
- void set_allocated_name(::std::string* PROTOBUF_NULLABLE value);
- private:
- const ::std::string& _internal_name() const;
- PROTOBUF_ALWAYS_INLINE void _internal_set_name(const ::std::string& value);
- ::std::string* PROTOBUF_NONNULL _internal_mutable_name();
- public:
- // int32 age = 2;
- void clear_age() ;
- ::int32_t age() const;
- void set_age(::int32_t value);
- private:
- ::int32_t _internal_age() const;
- void _internal_set_age(::int32_t value);
- public:
- // @@protoc_insertion_point(class_scope:contact.Info)
- private:
- class _Internal;
- friend class ::google::protobuf::internal::TcParser;
- static const ::google::protobuf::internal::TcParseTable<1, 2,
- 0, 25,
- 2>
- _table_;
- friend class ::google::protobuf::MessageLite;
- friend class ::google::protobuf::Arena;
- template <typename T>
- friend class ::google::protobuf::Arena::InternalHelper;
- using InternalArenaConstructable_ = void;
- using DestructorSkippable_ = void;
- struct Impl_ {
- inline explicit constexpr Impl_(::google::protobuf::internal::ConstantInitialized) noexcept;
- inline explicit Impl_(
- ::google::protobuf::internal::InternalVisibility visibility,
- ::google::protobuf::Arena* PROTOBUF_NULLABLE arena);
- inline explicit Impl_(
- ::google::protobuf::internal::InternalVisibility visibility,
- ::google::protobuf::Arena* PROTOBUF_NULLABLE arena, const Impl_& from,
- const Info& from_msg);
- ::google::protobuf::internal::HasBits<1> _has_bits_;
- ::google::protobuf::internal::CachedSize _cached_size_;
- ::google::protobuf::internal::ArenaStringPtr name_;
- ::int32_t age_;
- PROTOBUF_TSAN_DECLARE_MEMBER
- };
- union { Impl_ _impl_; };
- friend struct ::TableStruct_contact_2eproto;
- };
- extern const ::google::protobuf::internal::ClassDataFull Info_class_data_;
- // ===================================================================
- // ===================================================================
- #ifdef __GNUC__
- #pragma GCC diagnostic push
- #pragma GCC diagnostic ignored "-Wstrict-aliasing"
- #endif // __GNUC__
- // -------------------------------------------------------------------
- // Info
- // string name = 1;
- inline void Info::clear_name() {
- ::google::protobuf::internal::TSanWrite(&_impl_);
- _impl_.name_.ClearToEmpty();
- _impl_._has_bits_[0] &= ~0x00000001u;
- }
- inline const ::std::string& Info::name() const
- ABSL_ATTRIBUTE_LIFETIME_BOUND {
- // @@protoc_insertion_point(field_get:contact.Info.name)
- return _internal_name();
- }
- template <typename Arg_, typename... Args_>
- PROTOBUF_ALWAYS_INLINE void Info::set_name(Arg_&& arg, Args_... args) {
- ::google::protobuf::internal::TSanWrite(&_impl_);
- _impl_._has_bits_[0] |= 0x00000001u;
- _impl_.name_.Set(static_cast<Arg_&&>(arg), args..., GetArena());
- // @@protoc_insertion_point(field_set:contact.Info.name)
- }
- inline ::std::string* PROTOBUF_NONNULL Info::mutable_name()
- ABSL_ATTRIBUTE_LIFETIME_BOUND {
- ::std::string* _s = _internal_mutable_name();
- // @@protoc_insertion_point(field_mutable:contact.Info.name)
- return _s;
- }
- inline const ::std::string& Info::_internal_name() const {
- ::google::protobuf::internal::TSanRead(&_impl_);
- return _impl_.name_.Get();
- }
- inline void Info::_internal_set_name(const ::std::string& value) {
- ::google::protobuf::internal::TSanWrite(&_impl_);
- _impl_._has_bits_[0] |= 0x00000001u;
- _impl_.name_.Set(value, GetArena());
- }
- inline ::std::string* PROTOBUF_NONNULL Info::_internal_mutable_name() {
- ::google::protobuf::internal::TSanWrite(&_impl_);
- _impl_._has_bits_[0] |= 0x00000001u;
- return _impl_.name_.Mutable( GetArena());
- }
- inline ::std::string* PROTOBUF_NULLABLE Info::release_name() {
- ::google::protobuf::internal::TSanWrite(&_impl_);
- // @@protoc_insertion_point(field_release:contact.Info.name)
- if ((_impl_._has_bits_[0] & 0x00000001u) == 0) {
- return nullptr;
- }
- _impl_._has_bits_[0] &= ~0x00000001u;
- auto* released = _impl_.name_.Release();
- if (::google::protobuf::internal::DebugHardenForceCopyDefaultString()) {
- _impl_.name_.Set("", GetArena());
- }
- return released;
- }
- inline void Info::set_allocated_name(::std::string* PROTOBUF_NULLABLE value) {
- ::google::protobuf::internal::TSanWrite(&_impl_);
- if (value != nullptr) {
- _impl_._has_bits_[0] |= 0x00000001u;
- } else {
- _impl_._has_bits_[0] &= ~0x00000001u;
- }
- _impl_.name_.SetAllocated(value, GetArena());
- if (::google::protobuf::internal::DebugHardenForceCopyDefaultString() && _impl_.name_.IsDefault()) {
- _impl_.name_.Set("", GetArena());
- }
- // @@protoc_insertion_point(field_set_allocated:contact.Info.name)
- }
- // int32 age = 2;
- inline void Info::clear_age() {
- ::google::protobuf::internal::TSanWrite(&_impl_);
- _impl_.age_ = 0;
- _impl_._has_bits_[0] &= ~0x00000002u;
- }
- inline ::int32_t Info::age() const {
- // @@protoc_insertion_point(field_get:contact.Info.age)
- return _internal_age();
- }
- inline void Info::set_age(::int32_t value) {
- _internal_set_age(value);
- _impl_._has_bits_[0] |= 0x00000002u;
- // @@protoc_insertion_point(field_set:contact.Info.age)
- }
- inline ::int32_t Info::_internal_age() const {
- ::google::protobuf::internal::TSanRead(&_impl_);
- return _impl_.age_;
- }
- inline void Info::_internal_set_age(::int32_t value) {
- ::google::protobuf::internal::TSanWrite(&_impl_);
- _impl_.age_ = value;
- }
- #ifdef __GNUC__
- #pragma GCC diagnostic pop
- #endif // __GNUC__
- // @@protoc_insertion_point(namespace_scope)
- } // namespace contact
- // @@protoc_insertion_point(global_scope)
- #include "google/protobuf/port_undef.inc"
- #endif // contact_2eproto_2epb_2eh
复制代码 假如在main函数中需要对PersonInfo类进利用用,需要包含生成的头文件,别的在编译的时候,还需要指定使用-std=c++11选项以及编译连接库 -lprotobuf。
示例:
- #include<iostream>
- #include"contact.pb.h"
- #include<string>
- using std::endl;
- using std::cout;
- using std::cerr;
- int main()
- {
- std::string people_str;
- {
- contact::PersonInfo info1;
- info1.set_age(21);
- info1.set_name("张三");
- if(!info1.SerializeToString(&people_str))
- {
- cerr<<"序列化失败"<<endl;
- exit(-1);
- }
- cout<<"序列化成功"<<endl;
- cout<<"people_str:"<<people_str<<endl;
- cout<<"---------------------------------"<<endl;
- }
- {
- contact::PersonInfo info1;
-
- if(!info1.ParseFromString(people_str))
- {
- cerr<<"反序列化失败"<<endl;
- exit(-1);
- }
- cout<<"反序列化成功"<<endl;
- cout<<"name:"<<info1.name()<<endl;
- cout<<"age:"<<info1.age()<<endl;
- }
- return 0;
- }
复制代码 运行结果:
4、在网络通讯或存储中使用protobuf序列化数据
和本地是类似的,这里不再演示,在反面的讲解和实际项目中再详细展示。
四、快速上手写一个小需求来熟悉怎样编写proto文件?
需求: 我们正在开发一个简单的图书管理体系。需要在客户端和服务器之间传输图书信息。每本图书包含以下内容:
- 图书ID(整数)
- 书名(字符串)
- 作者(字符串)
- 出书年份(整数,可选)
- 是否借出(布尔值)
- 借阅人(字符串,可选,仅在借出时填写)
请根据这个需求,设计一个合适的proto文件。
比较美满的答案如下:
- //声明语法版本
- syntax = "proto3";
- package books;
- // 单本图书信息
- message Book {
- int64 id = 1; // 图书ID
- string title = 2; // 书名
- string author = 3; // 作者
- int32 year = 4; // 出版年份(可选,未知为0)
- bool is_borrowed = 5; // 是否借出
- string borrower = 6; // 借阅人(仅借出时填写,否则为空字符串)
- }
复制代码 完~
未经作者同意克制转载
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