From 741dd45f676faa94151f723776e07d5a72a52c39 Mon Sep 17 00:00:00 2001
From: Mat Sutcliffe <oktal3700@gmail.com>
Date: Tue, 26 Feb 2019 01:51:43 +0000
Subject: [PATCH] Issue #15 Added CActiveObserver and CActiveMutator

These extend CPassiveObserver and CPassiveMutator with a one-to-many request/reply pattern.
---
 src/blackmisc/sharedstate/activemutator.cpp  | 22 ++++++++
 src/blackmisc/sharedstate/activemutator.h    | 56 +++++++++++++++++++
 src/blackmisc/sharedstate/activeobserver.cpp | 35 ++++++++++++
 src/blackmisc/sharedstate/activeobserver.h   | 58 ++++++++++++++++++++
 4 files changed, 171 insertions(+)
 create mode 100644 src/blackmisc/sharedstate/activemutator.cpp
 create mode 100644 src/blackmisc/sharedstate/activemutator.h
 create mode 100644 src/blackmisc/sharedstate/activeobserver.cpp
 create mode 100644 src/blackmisc/sharedstate/activeobserver.h

diff --git a/src/blackmisc/sharedstate/activemutator.cpp b/src/blackmisc/sharedstate/activemutator.cpp
new file mode 100644
index 000000000..25dd4f5ea
--- /dev/null
+++ b/src/blackmisc/sharedstate/activemutator.cpp
@@ -0,0 +1,22 @@
+/* Copyright (C) 2017
+ * swift Project Community / Contributors
+ *
+ * This file is part of swift project. It is subject to the license terms in the LICENSE file found in the top-level
+ * directory of this distribution. No part of swift project, including this file, may be copied, modified, propagated,
+ * or distributed except according to the terms contained in the LICENSE file.
+ */
+
+//! \file
+
+#include "blackmisc/sharedstate/activemutator.h"
+
+namespace BlackMisc
+{
+    namespace SharedState
+    {
+        QFuture<CVariant> CActiveMutator::handleRequest(const CVariant& param) const
+        {
+            return m_requestHandler(param);
+        }
+    }
+}
diff --git a/src/blackmisc/sharedstate/activemutator.h b/src/blackmisc/sharedstate/activemutator.h
new file mode 100644
index 000000000..b6aeb10d4
--- /dev/null
+++ b/src/blackmisc/sharedstate/activemutator.h
@@ -0,0 +1,56 @@
+/* Copyright (C) 2017
+ * swift Project Community / Contributors
+ *
+ * This file is part of swift project. It is subject to the license terms in the LICENSE file found in the top-level
+ * directory of this distribution. No part of swift project, including this file, may be copied, modified, propagated,
+ * or distributed except according to the terms contained in the LICENSE file.
+ */
+
+//! \file
+
+#ifndef BLACKMISC_SHAREDSTATE_ACTIVEMUTATOR_H
+#define BLACKMISC_SHAREDSTATE_ACTIVEMUTATOR_H
+
+#include "blackmisc/sharedstate/passivemutator.h"
+#include "blackmisc/variant.h"
+#include "blackmisc/blackmiscexport.h"
+#include <QObject>
+#include <QFuture>
+#include <functional>
+
+namespace BlackMisc
+{
+    namespace SharedState
+    {
+        /*!
+         * Extends CPassiveMutator with the ability to respond to requests.
+         */
+        class BLACKMISC_EXPORT CActiveMutator final : public CPassiveMutator
+        {
+            Q_OBJECT
+            friend QSharedPointer<CActiveMutator>;
+
+            template <typename T, typename F>
+            CActiveMutator(T *parent, F requestHandler) :
+                CPassiveMutator(parent),
+                m_requestHandler([ = ](const CVariant &param) { return Private::invokeMethod(parent, requestHandler, param); })
+            {}
+
+        public:
+            //! Factory method.
+            template <typename T, typename F>
+            static auto create(T *parent, F requestHandler) { return QSharedPointer<CActiveMutator>::create(parent, requestHandler); }
+
+            //! Respond to a request and return a reply.
+            QFuture<CVariant> handleRequest(const CVariant& param) const;
+
+            //! Get a QWeakPointer pointing to this object.
+            QWeakPointer<const CActiveMutator> weakRef() const { return qSharedPointerCast<const CActiveMutator>(CPassiveMutator::weakRef()); }
+
+        private:
+            const std::function<QFuture<CVariant>(const CVariant &)> m_requestHandler;
+        };
+    }
+}
+
+#endif
diff --git a/src/blackmisc/sharedstate/activeobserver.cpp b/src/blackmisc/sharedstate/activeobserver.cpp
new file mode 100644
index 000000000..9d0110113
--- /dev/null
+++ b/src/blackmisc/sharedstate/activeobserver.cpp
@@ -0,0 +1,35 @@
+/* Copyright (C) 2017
+ * swift Project Community / Contributors
+ *
+ * This file is part of swift project. It is subject to the license terms in the LICENSE file found in the top-level
+ * directory of this distribution. No part of swift project, including this file, may be copied, modified, propagated,
+ * or distributed except according to the terms contained in the LICENSE file.
+ */
+
+//! \file
+
+#include "blackmisc/sharedstate/activeobserver.h"
+
+namespace BlackMisc
+{
+    namespace SharedState
+    {
+        CVariant CActiveObserver::request(const CVariant &param)
+        {
+            CPromise<CVariant> promise;
+            emit requestPosted(param, promise);
+            return promise.future().result();
+        }
+
+        void CActiveObserver::requestAsync(const CVariant &param, std::function<void(const CVariant &)> callback)
+        {
+            CPromise<CVariant> promise;
+            emit requestPosted(param, promise);
+            doAfter(promise.future(), this, [callback = std::move(callback), weakRef = weakRef()](const CVariant &reply)
+            {
+                const auto lock = weakRef.lock();
+                if (lock) { callback(reply); }
+            });
+        }
+    }
+}
diff --git a/src/blackmisc/sharedstate/activeobserver.h b/src/blackmisc/sharedstate/activeobserver.h
new file mode 100644
index 000000000..abc7df3ca
--- /dev/null
+++ b/src/blackmisc/sharedstate/activeobserver.h
@@ -0,0 +1,58 @@
+/* Copyright (C) 2017
+ * swift Project Community / Contributors
+ *
+ * This file is part of swift project. It is subject to the license terms in the LICENSE file found in the top-level
+ * directory of this distribution. No part of swift project, including this file, may be copied, modified, propagated,
+ * or distributed except according to the terms contained in the LICENSE file.
+ */
+
+//! \file
+
+#ifndef BLACKMISC_SHAREDSTATE_ACTIVEOBSERVER_H
+#define BLACKMISC_SHAREDSTATE_ACTIVEOBSERVER_H
+
+#include "blackmisc/sharedstate/passiveobserver.h"
+#include "blackmisc/promise.h"
+#include "blackmisc/variant.h"
+#include "blackmisc/blackmiscexport.h"
+#include <QObject>
+#include <QSharedPointer>
+
+namespace BlackMisc
+{
+    namespace SharedState
+    {
+        /*!
+         * Extends CPassiveObserver with the ability to send requests and receive replies.
+         */
+        class BLACKMISC_EXPORT CActiveObserver final : public CPassiveObserver
+        {
+            Q_OBJECT
+            friend QSharedPointer<CActiveObserver>;
+
+            template <typename T, typename F>
+            CActiveObserver(T *parent, F eventHandler) : CPassiveObserver(parent, eventHandler) {}
+
+        public:
+            //! Factory method.
+            template <typename T, typename F>
+            static auto create(T *parent, F eventHandler) { return QSharedPointer<CActiveObserver>::create(parent, eventHandler); }
+
+            //! Send a request and receive a synchronous reply.
+            CVariant request(const CVariant &param);
+
+            //! Send a request and receive an asynchronous reply.
+            //! The callback will not be called if the reply is received after the observer has been destroyed.
+            void requestAsync(const CVariant &param, std::function<void(const CVariant &)> callback);
+
+            //! Get a QWeakPointer pointing to this object.
+            QWeakPointer<const CActiveObserver> weakRef() const { return qSharedPointerCast<const CActiveObserver>(CPassiveObserver::weakRef()); }
+
+        signals:
+            //! Emitted by request and requestAsync.
+            void requestPosted(const CVariant &param, BlackMisc::CPromise<BlackMisc::CVariant> o_reply);
+        };
+    }
+}
+
+#endif