feat: implement tool to convert proto to struct pb

[helintongh]

proto file to struct pb.

[qicosmos]

不要用PUBLIC，使用完整的public iguana::base_impl。
另外可以增加一个参数：enable_reflection，如果设置为true，才从 iguana::base_impl派生。
默认情况下，不需要派生。
默认情况下构造函数也是不需要的，只有派生的时候才需要增加构造函数。

[codecov-commenter]

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All modified and coverable lines are covered by tests ✅

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@@            Coverage Diff             @@
##           master     #323      +/-   ##
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+ Coverage   45.64%   45.71%   +0.07%     
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  Lines        7582     7592      +10     
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[qicosmos]

把readme里面inherit 的两种情况都给个例子吧，看得清楚一点。

[helintongh]

把readme里面inherit 的两种情况都给个例子吧，看得清楚一点。

例子已经提供.

下面的多个文件的例子:

文件路径如下所示:

------------proto_dir
|---------component.proto
|---------computer.proto

其中component.proto如下:

syntax = "proto3";

option optimize_for = SPEED;
option cc_enable_arenas = true;

package import;

message CPU {
  string Name = 1;
  int64 Frequency = 2;
}
message Memory {
  string Name = 1;
  int64 Cap = 2;
}

computer.proto如下:

syntax = "proto3";
option optimize_for = SPEED;
option cc_enable_arenas = true;
package import;
import "proto_dir/component.proto";

message Computer {
  string name = 1;
  import.CPU cpu = 2;
  import.Memory memory = 3;
}

此时执行:

protoc --plugin=protoc-gen-custom=./build/proto_to_struct proto_dir/*    --custom_out=add_optional:./protos

生成文件component.proto.h如下:

#pragma once
#include <ylt/struct_pb.hpp>

struct CPU {
	std::optional<std::string> Name;
	int64_t Frequency;
};
YLT_REFL(CPU, Name, Frequency);

struct Memory {
	std::optional<std::string> Name;
	int64_t Cap;
};
YLT_REFL(Memory, Name, Cap);

computer.proto.h如下:

#pragma once
#include <ylt/struct_pb.hpp>

struct Computer {
	std::optional<std::string> name;
	std::optional<CPU> cpu;
	std::optional<Memory> memory;
};
YLT_REFL(Computer, name, cpu, memory);

可以看到生成的文件无误.

[qicosmos]

LGTM