From aaa97edf001e8a527fba8b8a5bcdfbe66d65e81f Mon Sep 17 00:00:00 2001
From: Alex Biddulph <abiddulph@4tel.com.au>
Date: Mon, 9 Oct 2023 16:36:26 +1100
Subject: [PATCH] Allow extra arguments to be passed to reactor constructor
 (#97)

---
 src/PowerPlant.hpp        |  7 +++--
 src/PowerPlant.ipp        |  7 +++--
 tests/api/ReactorArgs.cpp | 62 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 71 insertions(+), 5 deletions(-)
 create mode 100644 tests/api/ReactorArgs.cpp

diff --git a/src/PowerPlant.hpp b/src/PowerPlant.hpp
index 9ec3374db..ca1807483 100644
--- a/src/PowerPlant.hpp
+++ b/src/PowerPlant.hpp
@@ -121,12 +121,15 @@ class PowerPlant {
      *  in the environment of that reactor so that it can be used to filter logs.
      *
      * @tparam T        The type of the reactor to build and install
+     * @tparam Args     The types of the extra arguments to pass to the reactor constructor
      * @tparam level    The initial logging level for this reactor to use
      *
+     * @param arg       Extra arguments to pass to the reactor constructor
+     *
      * @return A reference to the installed reactor
      */
-    template <typename T>
-    T& install();
+    template <typename T, typename... Args>
+    T& install(Args&&... args);
 
     /**
      * @brief Generic submit function for submitting tasks to the thread pool.
diff --git a/src/PowerPlant.ipp b/src/PowerPlant.ipp
index 3f12de36b..002c15d5c 100644
--- a/src/PowerPlant.ipp
+++ b/src/PowerPlant.ipp
@@ -52,14 +52,15 @@ inline PowerPlant::PowerPlant(Configuration config, int argc, const char* argv[]
     emit(std::make_unique<message::CommandLineArguments>(args));
 }
 
-template <typename T>
-T& PowerPlant::install() {
+template <typename T, typename... Args>
+T& PowerPlant::install(Args&&... args) {
 
     // Make sure that the class that we received is a reactor
     static_assert(std::is_base_of<Reactor, T>::value, "You must install Reactors");
 
     // The reactor constructor should handle subscribing to events
-    reactors.push_back(std::make_unique<T>(std::make_unique<Environment>(*this, util::demangle(typeid(T).name()))));
+    reactors.push_back(std::make_unique<T>(std::make_unique<Environment>(*this, util::demangle(typeid(T).name())),
+                                           std::forward<Args>(args)...));
 
     return static_cast<T&>(*reactors.back());
 }
diff --git a/tests/api/ReactorArgs.cpp b/tests/api/ReactorArgs.cpp
new file mode 100644
index 000000000..07ba1ffd5
--- /dev/null
+++ b/tests/api/ReactorArgs.cpp
@@ -0,0 +1,62 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2015 NUClear Contributors
+ *
+ * This file is part of the NUClear codebase.
+ * See https://github.com/Fastcode/NUClear for further info.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated
+ * documentation files (the "Software"), to deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
+ * WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+ * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <catch.hpp>
+#include <nuclear>
+
+// Anonymous namespace to keep everything file local
+namespace {
+
+class TestReactorNoArgs : public NUClear::Reactor {
+public:
+    TestReactorNoArgs(std::unique_ptr<NUClear::Environment> environment) : NUClear::Reactor(std::move(environment)) {}
+
+    std::string s{};
+    bool b{false};
+    uint32_t i{0};
+};
+class TestReactorArgs : public NUClear::Reactor {
+public:
+    TestReactorArgs(std::unique_ptr<NUClear::Environment> environment, std::string s, const bool& b, const uint32_t& i)
+        : NUClear::Reactor(std::move(environment)), s(std::move(s)), b(b), i(i) {}
+
+    std::string s{};
+    bool b{false};
+    uint32_t i{0};
+};
+
+}  // namespace
+
+TEST_CASE("Testing Reactor installation arguments", "[api][reactorargs]") {
+    NUClear::Configuration config;
+    config.thread_count = 1;
+    NUClear::PowerPlant plant(config);
+    const TestReactorArgs& r1   = plant.install<TestReactorArgs>("Hello NUClear", true, 0x00E298A2);
+    const TestReactorNoArgs& r2 = plant.install<TestReactorNoArgs>();
+
+    REQUIRE(r1.s == "Hello NUClear");
+    REQUIRE(r1.b);
+    REQUIRE(r1.i == 0x00E298A2);
+    REQUIRE(r2.s.empty());
+    REQUIRE(!r2.b);
+    REQUIRE(r2.i == 0);
+}