User-Defined Data Types in Messages（用戶自定義類型）
All user-defined types must be explicitly “announced” so that CAF can (de)serialize them correctly.

之前干活，一開始不知道CAF自帶序列化，都用boost庫來做序列化，就是變string 類型發送，發現很多STL有些搞搞比較麻煩，發現誒？CAF居然比boost庫好使！

那么就來搞一下看看.

先看一個例子（也是usermanual 里唯一的一個例子，呵呵呵～）其他的例子在github官網里https://github.com/actor-framework/actor-framework/tree/master/examples/type_system?（就五個收益很大）

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沒看錯就是那么簡單的使用，announce函數。第一個參數是一個string那么之后就是他的所有成員。怎么實現我也不是很懂，上圖

大致就是TS 就是參數的類型，可以是可變長度，然后檢查他們的類型，我第一看到Is_pod 查了一下（pod類型 是plain old data）就是完全兼容C語言的編程的。（漲姿勢了～）

還有uniform_type_info是CAF自己的一個關于類型什么的（沒深究，只知道與RTTI有關）。還有一個重要的地方就是你必須寫明你要發送的結構體的比較函數 ==（下面代碼上有）

進入正題。（announce1.cpp）代碼有一點點小長但是信息量很大。

// POD struct struct foo {std::vector<int> a;int b; };// announce requires foo to have the equal operator implemented bool operator==(const foo& lhs, const foo& rhs) {return lhs.a == rhs.a && lhs.b == rhs.b; }// a pair of two ints using foo_pair = std::pair<int, int>;// another pair of two ints using foo_pair2 = std::pair<int, int>;// a struct with member vector<vector<...>> struct foo2 {int a;vector<vector<double>> b; };bool operator==(const foo2& lhs, const foo2& rhs) {return lhs.a == rhs.a && lhs.b == rhs.b; }// receives `remaining` messages void testee(event_based_actor* self, size_t remaining) {auto set_next_behavior = [=] {if (remaining > 1) testee(self, remaining - 1);else self->quit();};self->become (// note: we sent a foo_pair2, but match on foo_pair// that's safe because both are aliases for std::pair<int, int>[=](const foo_pair& val) {cout << "foo_pair("<< val.first << ", "<< val.second << ")"<< endl;set_next_behavior();},[=](const foo& val) {cout << "foo({";auto i = val.a.begin();auto end = val.a.end();if (i != end) {cout << *i;while (++i != end) {cout << ", " << *i;}}cout << "}, " << val.b << ")" << endl;set_next_behavior();}); }int main(int, char**) {// announces foo to the libcaf type system;// the function expects member pointers to all elements of fooannounce<foo>("foo", &foo::a, &foo::b);// announce foo2 to the libcaf type system,// note that recursive containers are managed automatically by libcafannounce<foo2>("foo2", &foo2::a, &foo2::b);// serialization can throw if types are not announced properlytry {// init some test data foo2 vd;vd.a = 5;vd.b.resize(1);vd.b.back().push_back(42);// serialize test datavector<char> buf;binary_serializer bs(std::back_inserter(buf));bs << vd;// deserialize written test data from buffer binary_deserializer bd(buf.data(), buf.size());foo2 vd2;uniform_typeid<foo2>()->deserialize(&vd2, &bd);// deserialized data must be equal to original inputassert(vd == vd2);// announce std::pair<int, int> to the type systemannounce<foo_pair>("foo_pair", &foo_pair::first, &foo_pair::second);// libcaf returns the same uniform_type_info// instance for the type aliases foo_pair and foo_pair2assert(uniform_typeid<foo_pair>() == uniform_typeid<foo_pair2>());}catch (std::exception& e) {cerr << "error during type (de)serialization: " << e.what() << endl;return -1;}// spawn a testee that receives two messages of user-defined typeauto t = spawn(testee, size_t{2});{ // lifetime scope of self scoped_actor self;// send t a fooself->send(t, foo{std::vector<int>{1, 2, 3, 4}, 5});// send t a foo_pair2self->send(t, foo_pair2{3, 4});}await_all_actors_done();shutdown(); }

一開始看，就是聲明了兩種結構體。foo 和foo2，foo2里面有vector<vector<double>> b（其實這里就告訴我們，它不但支持STL，還支持嵌套，而且我親測pair，map都是可以的。其他應該也沒問題吧。）

然后testee里定義了接受兩種類型的消息一種是<int,int>（不管別名）,一種是結構體foo 是的沒看錯，都不用序列化了，直接傳（// note that recursive containers are managed automatically by libcaf）。

真心方便，然后是main函數里，使用了二進制去序列化類，再使用反序列化，整個過程就像用讀文件非常的方便(注意捕獲異常)。那么在最后的scoped_actor send也直接把類傳過去非常的方便。

為了證明好用，支持remote actor我寫了一個很難看的代碼。

#include <vector> #include <iostream> #include "caf/all.hpp" #include "caf/io/all.hpp" using std::cout; using std::endl; using std::vector; using std::map; using std::pair; using namespace caf;struct foo {std::vector<vector<map<int,pair<int,int>>>> a;int b; }; bool operator==(const foo& lhs, const foo& rhs) {return lhs.a == rhs.a && lhs.b == rhs.b; } // receives `remaining` messages void testee(event_based_actor* self) {self->become ([=](const foo& val) {aout(self)<<"get it"<<endl;}); } int main(int, char**) { // announce<foo2>("foo2", &foo2::a, &foo2::b);announce<foo>("foo", &foo::a, &foo::b);auto actor = spawn(testee);caf::io::publish(actor,10000);{ // lifetime scope of self scoped_actor self;auto remoter = caf::io::remote_actor("localhost", 10000);self->send(remoter, foo{std::vector<vector<map<int,pair<int,int>>>>{},1,});}await_all_actors_done();shutdown(); }

結果為

不得不服還是很方便的！

碼字不容易，求粉絲～互粉呀～

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轉載于:https://www.cnblogs.com/zhejiangxiaomai/p/5259625.html

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