libcaf  0.13.2
announce_4.cpp

An example for announce with non-primitive members.The output of this example program is:

bar(foo(1, 2), 3)

#include <iostream>
#include "caf/all.hpp"
#include "caf/to_string.hpp"
using std::cout;
using std::endl;
using std::make_pair;
using namespace caf;
// the foo class from example 3
class foo {
int a_;
int b_;
public:
foo() : a_(0), b_(0) { }
foo(int a0, int b0) : a_(a0), b_(b0) { }
foo(const foo&) = default;
foo& operator=(const foo&) = default;
int a() const { return a_; }
void set_a(int val) { a_ = val; }
int b() const { return b_; }
void set_b(int val) { b_ = val; }
};
// needed for operator==() of bar
bool operator==(const foo& lhs, const foo& rhs) {
return lhs.a() == rhs.a()
&& lhs.b() == rhs.b();
}
// simple struct that has foo as a member
struct bar {
foo f;
int i;
};
// announce requires bar to have the equal operator implemented
bool operator==(const bar& lhs, const bar& rhs) {
return lhs.f == rhs.f
&& lhs.i == rhs.i;
}
// "worst case" class ... not a good software design at all ;)
class baz {
foo f_;
public:
bar b;
// announce requires a default constructor
baz() = default;
inline baz(const foo& mf, const bar& mb) : f_(mf), b(mb) { }
const foo& f() const { return f_; }
void set_f(const foo& val) { f_ = val; }
};
// even worst case classes have to implement operator==
bool operator==(const baz& lhs, const baz& rhs) {
return lhs.f() == rhs.f()
&& 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 (
on<bar>() >> [=](const bar& val) {
aout(self) << "bar(foo("
<< val.f.a() << ", "
<< val.f.b() << "), "
<< val.i << ")"
<< endl;
set_next_behavior();
},
on<baz>() >> [=](const baz& val) {
// prints: baz ( foo ( 1, 2 ), bar ( foo ( 3, 4 ), 5 ) )
aout(self) << to_string(make_message(val)) << endl;
set_next_behavior();
}
);
}
int main(int, char**) {
// bar has a non-trivial data member f, thus, we have to told
// announce how to serialize/deserialize this member;
// this is was the compound_member function is for;
// it takes a pointer to the non-trivial member as first argument
// followed by all "sub-members" either as member pointer or
// { getter, setter } pair
auto meta_bar_f = [] {
return compound_member(&bar::f,
make_pair(&foo::a, &foo::set_a),
make_pair(&foo::b, &foo::set_b));
};
// with meta_bar_f, we can now announce bar
announce<bar>("bar", meta_bar_f(), &bar::i);
// baz has non-trivial data members with getter/setter pair
// and getter returning a mutable reference
announce<baz>("baz", compound_member(make_pair(&baz::f, &baz::set_f),
make_pair(&foo::a, &foo::set_a),
make_pair(&foo::b, &foo::set_b)),
// compound member that has a compound member
compound_member(&baz::b, meta_bar_f(), &bar::i));
// spawn a testee that receives two messages
auto t = spawn(testee, 2);
{
self->send(t, bar{foo{1, 2}, 3});
self->send(t, baz{foo{1, 2}, bar{foo{3, 4}, 5}});
}
return 0;
}