add Dealer interfaces

iface/CMakeLists.txt

@@ -9,6 +9,7 @@ target_sources(nf7_iface
   PRIVATE
     version.cc
   PUBLIC
+    common/dealer.hh
     common/container.hh
     common/future.hh
     common/observer.hh
@@ -18,6 +19,7 @@ target_sources(nf7_iface
 add_executable(nf7_iface_test)
 target_sources(nf7_iface_test
   PRIVATE
+    common/dealer_test.cc
     common/container_test.cc
     common/future_test.cc
     common/observer_test.hh

iface/common/dealer.hh

@@ -0,0 +1,65 @@
+// No copyright
+#pragma once
+
+#include <string>
+#include <utility>
+
+#include "iface/common/observer.hh"
+
+
+namespace nf7 {
+
+struct DealerMeta {
+ public:
+  std::string name;
+  std::string description;
+};
+
+template <typename T>
+class Dealer {
+ public:
+  explicit Dealer(const DealerMeta& meta) noexcept : meta_(meta) { }
+  virtual ~Dealer() = default;
+
+  Dealer(const Dealer&) = default;
+  Dealer(Dealer&&) = default;
+  Dealer& operator=(const Dealer&) = default;
+  Dealer& operator=(Dealer&&) = default;
+
+  const DealerMeta& meta() const noexcept { return meta_; }
+
+ private:
+  const DealerMeta& meta_;
+};
+
+template <typename T>
+class Maker : public Dealer<T>, public Observer<T>::Target {
+ public:
+  explicit Maker(const DealerMeta& meta) noexcept : Dealer<T>(meta) { }
+
+ protected:
+  void Emit(T&& v) noexcept { Observer<T>::Target::Notify(std::move(v)); }
+};
+
+template <typename T>
+class Emitter : public Maker<T> {
+ public:
+  explicit Emitter(const DealerMeta& meta) noexcept : Maker<T>(meta) { }
+  using Maker<T>::Emit;
+};
+
+template <typename T>
+class Taker : public Dealer<T>, public Observer<T>::Target {
+ public:
+  explicit Taker(const DealerMeta& meta) noexcept : Dealer<T>(meta) { }
+
+  void Take(const T& v) noexcept {
+    Notify(v);
+    onTake();
+  }
+
+ protected:
+  virtual void onTake() noexcept = 0;
+};
+
+}  // namespace nf7

iface/common/dealer_test.cc

@@ -0,0 +1,16 @@
+// No copyright
+#include "iface/common/dealer.hh"
+
+#include <gtest/gtest.h>
+
+#include "iface/common/observer_test.hh"
+
+
+TEST(Emitter, Emit) {
+  nf7::Emitter<int32_t> sut {{"hello", "this is a maker"}};
+  nf7::test::ObserverMock<int32_t> obs {sut};
+
+  EXPECT_CALL(obs, NotifyWithMove(int32_t {777})).Times(1);
+
+  sut.Emit(int32_t {777});
+}