From 7342bc84f52e2f27fd08e3e3a0392acaabade624 Mon Sep 17 00:00:00 2001
From: Andrew Meadows <andrew@highfidelity.io>
Date: Mon, 12 Feb 2018 16:20:33 -0800
Subject: [PATCH] 'Hello world.' implementation of a Job engine

---
 libraries/workload/src/workload/Engine.cpp | 57 ++++++++++++++++
 libraries/workload/src/workload/Engine.h   | 76 ++++++++++++++++++++++
 2 files changed, 133 insertions(+)
 create mode 100644 libraries/workload/src/workload/Engine.cpp
 create mode 100644 libraries/workload/src/workload/Engine.h

diff --git a/libraries/workload/src/workload/Engine.cpp b/libraries/workload/src/workload/Engine.cpp
new file mode 100644
index 0000000000..7e69731d4e
--- /dev/null
+++ b/libraries/workload/src/workload/Engine.cpp
@@ -0,0 +1,57 @@
+//
+//  Engine.cpp
+//  libraries/workload/src/workload
+//
+//  Created by Andrew Meadows 2018.02.08
+//  Copyright 2018 High Fidelity, Inc.
+//
+//  Originally from lighthouse3d. Modified to utilize glm::vec3 and clean up to our coding standards
+//  Simple plane class.
+//
+//  Distributed under the Apache License, Version 2.0.
+//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
+//
+
+#include "Engine.h"
+
+#include <iostream>
+
+namespace workload {
+
+    // the "real Job"
+    class HelloWorld {
+        QString _message;
+        bool _isEnabled { true };
+    public:
+        using JobModel = Job::Model<HelloWorld, HelloWorldConfig>;
+        HelloWorld() {}
+        void configure(const HelloWorldConfig& configuration) {
+            _isEnabled = configuration.isEnabled();
+            _message = configuration.getMessage();
+        }
+        void run(const WorkloadContextPointer& context) {
+            if (_isEnabled) {
+                std::cout << _message.toStdString() << std::endl;
+            }
+	    }
+    };
+
+    WorkloadContext::WorkloadContext() : task::JobContext(trace_workload()) {}
+
+    using EngineModel = Task::Model<class HelloWorldBuilder>;
+
+    // the 'Builder' is the 'Data' on which the EngineModel templatizes.
+    // It must implement build() which is called by EngineModel::create().
+    class HelloWorldBuilder {
+    public:
+        using JobModel = Task::Model<EngineModel>;
+        void build(EngineModel& model, const Varying& in, Varying& out) {
+            model.addJob<HelloWorld>("helloWorld");
+        }
+    };
+
+    Engine::Engine() : Task("Engine", EngineModel::create()),
+            _context(std::make_shared<WorkloadContext>()) {
+    }
+} // namespace workload
+
diff --git a/libraries/workload/src/workload/Engine.h b/libraries/workload/src/workload/Engine.h
new file mode 100644
index 0000000000..a422c5d715
--- /dev/null
+++ b/libraries/workload/src/workload/Engine.h
@@ -0,0 +1,76 @@
+//
+//  Engine.h
+//  libraries/workload/src/workload
+//
+//  Created by Andrew Meadows 2018.02.08
+//  Copyright 2018 High Fidelity, Inc.
+//
+//  Originally from lighthouse3d. Modified to utilize glm::vec3 and clean up to our coding standards
+//  Simple plane class.
+//
+//  Distributed under the Apache License, Version 2.0.
+//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
+//
+
+#ifndef hifi_workload_Engine_h
+#define hifi_workload_Engine_h
+
+#include <QtCore/QObject>
+#include <QLoggingCategory>
+
+#include <task/Task.h>
+
+namespace workload {
+
+    // How to make an Engine under the task::Task<C> paradigm...
+
+    // (1) Derive class C from task::JobContext
+    class WorkloadContext : public task::JobContext {
+    public:
+        WorkloadContext();
+        virtual ~WorkloadContext() {}
+    };
+    using WorkloadContextPointer = std::shared_ptr<WorkloadContext>;
+
+    // (2) Apply a macro which will create local aliases (via "using") for example:
+    //     using Task = task::Task<C>;
+    Task_DeclareTypeAliases(WorkloadContext)
+
+    // (3) You'll need a 'real Job' but it will need a Config for exposing settings to JS,
+    // and you should do that here:
+    class HelloWorldConfig : public Job::Config {
+        Q_OBJECT
+        Q_PROPERTY(QString message READ getMessage WRITE setMessage)
+        QString _message {"Hello World."};
+    public:
+	    HelloWorldConfig() : Job::Config(true) {}
+        QString getMessage() const { return _message; }
+        void setMessage(const QString& msg) { _message = msg; }
+    };
+
+    // (4) In cpp file the 'real Job' will need a 'builder'.  The 'builder' is the 'Data' argument
+    // for the Model template.
+    // Data must implement Data::build().
+    // Data::build() is called when the Model is added (in Engine ctor) as the first child job of the Engine
+
+    // (5) Engine derives from task::Task<C> and will run all the Job<C>'s
+    class Engine : public Task {
+    public:
+        Engine();
+        ~Engine() = default;
+
+        // (6) The Engine's Context is passed to its Jobs when they are run()
+        void run() { assert(_context); Task::run(_context); }
+
+    protected:
+        // (6) Again, the Engine's Context is passed to its Jobs when they are run()
+        void run(const WorkloadContextPointer& context) override { assert(_context);  Task::run(_context); }
+
+    private:
+        WorkloadContextPointer _context;
+    };
+    using EnginePointer = std::shared_ptr<Engine>;
+
+} // namespace workload
+
+#endif // hifi_workload_Space_h