Migrating to real Observer design pattern usage

Change-Id: I2fa4e1dc81f5dff852e619a425b8caf26b94b55a
Signed-off-by: Romain Forlot <romain.forlot@iot.bzh>

3 files changed, 214 insertions, 30 deletions

diff --git a/signal-composer-binding/observer-pattern.hpp b/signal-composer-binding/observer-pattern.hpp
new file mode 100644
index 0000000..aba2847
--- /dev/null
+++ b/signal-composer-binding/observer-pattern.hpp
@@ -0,0 +1,139 @@
+/*
+ * Copyright (C) 2015, 2016 "IoT.bzh"
+ * Author "Romain Forlot" <romain.forlot@iot.bzh>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *	http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+*/
+
+/* This is a classic observer design pattern a bit enhanced to be
+ able to pull and push info in 2 ways */
+
+
+ #include <list>
+ #include <algorithm>
+
+template<class T>
+class Observable;
+
+template<class T>
+class Observer
+{
+protected:
+	virtual ~Observer()
+	{
+		const_iterator_ ite = observableList_.end();
+
+		for(iterator_ itb=observableList_.begin();itb!=ite;++itb)
+		{
+				(*itb)->delObserver(this);
+		}
+	}
+
+	std::list<Observable<T>*> observableList_;
+	typedef typename std::list<Observable<T>*>::iterator iterator_;
+	typedef typename std::list<Observable<T>*>::const_iterator const_iterator_;
+
+public:
+	virtual void update(T* observable) = 0;
+
+	void addObservable(Observable<T>* observable)
+	{
+		for (auto& obs : observableList_)
+		{
+			if (obs == observable)
+				{return;}
+		}
+
+		observableList_.push_back(observable);
+	}
+
+	void delObservable(Observable<T>* observable)
+	{
+		const_iterator_ it = std::find(observableList_.begin(), observableList_.end(), observable);
+		if(it != observableList_.end())
+			{observableList_.erase(it);}
+	}
+/*
+	void recursionCheck(T* obs)
+	{
+		for (const auto& obs: observersList_)
+		{
+			if( id_ == obs->id())
+				{return -1;}
+			if( origId == obs->id())
+				{return -1;}
+			if(! obs->recursionCheck(origId))
+				{return -1;}
+		}
+		return 0;
+	}
+*/
+};
+
+template <class T>
+class Observable
+{
+private:
+	std::list<Observer<T>*> observerList_;
+	typedef typename std::list<Observer<T>*>::iterator iterator_;
+	typedef typename std::list<Observer<T>*>::const_iterator const_iterator_;
+
+public:
+	void addObserver(Observer<T>* observer)
+	{
+		observerList_.push_back(observer);
+		observer->addObservable(this);
+	}
+
+	void delObserver(Observer<T>* observer)
+	{
+		const_iterator_ it = find(observerList_.begin(), observerList_.end(), observer);
+		if(it != observerList_.end())
+			{observerList_.erase(it);}
+	}
+/*
+	int recursionCheck()
+	{
+		for (auto& obs: observerList_)
+		{
+			if( static_cast<T*>(obs) == static_cast<T*>(this))
+				{return -1;}
+			if( obs->recursionCheck(id_))
+				{return -1;}
+		}
+		return 0;
+	}
+*/
+	virtual ~Observable()
+	{
+		iterator_ itb = observerList_.begin();
+		const_iterator_ ite = observerList_.end();
+
+		for(;itb!=ite;++itb)
+		{
+			(*itb)->delObservable(this);
+		}
+	}
+
+protected:
+	void notify()
+	{
+		iterator_ itb=observerList_.begin();
+		const_iterator_ ite=observerList_.end();
+
+		for(;itb!=ite;++itb)
+		{
+			(*itb)->update(static_cast<T*>(this));
+		}
+	}
+};
diff --git a/signal-composer-binding/signal.cpp b/signal-composer-binding/signal.cpp
index 2d49c3c..2dcc552 100644
--- a/signal-composer-binding/signal.cpp
+++ b/signal-composer-binding/signal.cpp
@@ -88,23 +88,30 @@ json_object* Signal::toJSON() const
 			dependsSignalName.push_back(src.substr(sep+1));
 		}
 	}
-	json_object* nameArray = json_object_new_array();
+	json_object *nameArrayJ = json_object_new_array();
 	for (const std::string& lowSig: dependsSignalName)
 	{
-		json_object_array_add(nameArray, json_object_new_string(lowSig.c_str()));
+		json_object_array_add(nameArrayJ, json_object_new_string(lowSig.c_str()));
 	}
-	wrap_json_pack(&queryJ, "{ss,ss*,so*,ss*,sf*,so*}",
+
+	wrap_json_pack(&queryJ, "{ss,so*}",
 			"id", id_.c_str(),
-			"event", event_.c_str(),
-			"depends", nameArray,
-			"unit", unit_.c_str(),
-			"frequency", frequency_,
 			"getSignalsArgs", getSignalsArgs_);
 
+	if (!event_.empty()) {json_object_object_add(queryJ, "event", json_object_new_string(event_.c_str()));}
+	if (json_object_array_length(nameArrayJ)) {json_object_object_add(queryJ, "depends", nameArrayJ);}
+	if (!unit_.empty()) {json_object_object_add(queryJ, "unit", json_object_new_string(unit_.c_str()));}
+	if (frequency_) {json_object_object_add(queryJ, "frequency", json_object_new_double(frequency_));}
+
+	if(timestamp_) {json_object_object_add(queryJ, "timestamp", json_object_new_int64(timestamp_));}
+
+	if (value_.hasBool) {json_object_object_add(queryJ, "value", json_object_new_boolean(value_.boolVal));}
+	else if (value_.hasNum) {json_object_object_add(queryJ, "value", json_object_new_double(value_.numVal));}
+	else if (value_.hasStr) {json_object_object_add(queryJ, "value", json_object_new_string(value_.strVal.c_str()));}
+
 	return queryJ;
 }
 
-
 /// @brief Set Signal timestamp and value property when an incoming
 /// signal arrived. Called by a plugin because treatment can't be
 /// standard as signals sources format could changes. See low-can plugin
@@ -121,11 +128,10 @@ void Signal::set(long long int timestamp, struct SignalValue& value)
 
 /// @brief Observer method called when a Observable Signal has changes.
 ///
-/// @param[in] timestamp - timestamp of occured signal
-/// @param[in] value - value of change
-void Signal::update(long long int timestamp, struct SignalValue value)
+/// @param[in] Observable - object from which update come from
+void Signal::update(Signal* sig)
 {
-	AFB_DEBUG("Got an update from observed signal. Timestamp: %lld, vb: %d, vn: %lf, vs: %s", timestamp, value.boolVal, value.numVal, value.strVal.c_str());
+	AFB_NOTICE("Got an update from observed signal %s", sig->id().c_str());
 }
 
 /// @brief Notify observers that there is a change and execute callback defined
@@ -145,7 +151,7 @@ int Signal::onReceivedCB(json_object *queryJ)
 /// present in the Observers vector.
 ///
 /// @param[in] obs - pointer to a Signal observable
-void Signal::attach(Signal* obs)
+/*void Signal::attach(Signal* obs)
 {
 	for ( auto& sig : Observers_)
 	{
@@ -154,7 +160,7 @@ void Signal::attach(Signal* obs)
 	}
 
 	Observers_.push_back(obs);
-}
+}*/
 
 /// @brief Make a Signal observer observes Signals observables
 /// set in its observable vector.
@@ -166,11 +172,11 @@ void Signal::attachToSourceSignals(Composer& composer)
 	{
 		if(srcSig.find("/") == std::string::npos)
 		{
-			std::vector<std::shared_ptr<Signal>> sig = composer.searchSignals(srcSig);
-			if(sig[0])
+			std::vector<Signal*> observables = composer.searchSignals(srcSig);
+			if(observables[0])
 			{
 				AFB_NOTICE("Attaching %s to %s", id_.c_str(), srcSig.c_str());
-				sig[0]->attach(this);
+				observables[0]->addObserver(this);
 				continue;
 			}
 			AFB_WARNING("Can't attach. Is %s exists ?", srcSig.c_str());
@@ -180,7 +186,7 @@ void Signal::attachToSourceSignals(Composer& composer)
 
 /// @brief Call update() method on observer Signal with
 /// current Signal timestamp and value
-void Signal::notify() const
+/*void Signal::notify() const
 {
 	for (int i = 0; i < Observers_.size(); ++i)
 	  Observers_[i]->update(timestamp_, value_);
@@ -194,7 +200,7 @@ void Signal::notify() const
 /// @return 0 if no infinite loop detected, -1 if not.
 int Signal::recursionCheck(const std::string& origId) const
 {
-	for (const auto& obs: Observers_)
+	for (const auto& obs: observersList_)
 	{
 		if( id_ == obs->id())
 			{return -1;}
@@ -214,7 +220,7 @@ int Signal::recursionCheck(const std::string& origId) const
 /// @return 0 if no infinite loop detected, -1 if not.
 int Signal::recursionCheck() const
 {
-	for (const auto& obs: Observers_)
+	for (const auto& obs: observersList_)
 	{
 		if( id_ == obs->id())
 			{return -1;}
@@ -222,7 +228,7 @@ int Signal::recursionCheck() const
 			{return -1;}
 	}
 	return 0;
-}
+}*/
 
 /// @brief Make an average over the last X 'seconds'
 ///
@@ -332,3 +338,40 @@ struct SignalValue Signal::last() const
 {
 	return history_.rbegin()->second;
 }
+
+/*
+template<class Signal>
+Observable<Signal>::~Observable()
+{
+	iterator_ itb = observerList_.begin();
+	const_iterator_ ite = observerList_.end();
+
+	for(;itb!=ite;++itb)
+	{
+		(*itb)->delObservable(this);
+	}
+}
+
+template <class Signal>
+Observer<Signal>::~Observer()
+{
+	const_iterator_ ite = observableList_.end();
+
+	for(iterator_ itb=observableList_.begin();itb!=ite;++itb)
+	{
+			(*itb)->delObserver(this);
+	}
+}
+
+template <class Signal>
+void Observable<Signal>::notify()
+{
+	iterator_ itb=observerList_.begin();
+	const_iterator_ ite=observerList_.end();
+
+	for(;itb!=ite;++itb)
+	{
+		(*itb)->update(static_cast<Signal*>(this));
+	}
+}
+*/
diff --git a/signal-composer-binding/signal.hpp b/signal-composer-binding/signal.hpp
index 870843e..8d0d1ab 100644
--- a/signal-composer-binding/signal.hpp
+++ b/signal-composer-binding/signal.hpp
@@ -22,8 +22,15 @@
 #include <vector>
 #include <ctl-config.h>
 
+#include "observer-pattern.hpp"
+
 class Composer;
 
+/// @brief Structure holding a possible value of a Signal
+///  as it could be different type of value, we declare all
+///  possibility.
+///  Not very efficient or optimized, maybe use of Variant in
+///  C++17 but this is a bit too new to uses it for now
 struct SignalValue {
 	bool hasBool = false;
 	bool boolVal;
@@ -33,7 +40,7 @@ struct SignalValue {
 	std::string strVal;
 };
 
-class Signal
+class Signal: public Observable<Signal>, public Observer<Signal>
 {
 private:
 	std::string id_;
@@ -47,12 +54,7 @@ private:
 	CtlActionT* onReceived_;
 	json_object* getSignalsArgs_;
 
-	std::vector<Signal*> Observers_;
-
-	void notify() const;
-	void attach(Signal *obs);
-	int recursionCheck(const std::string& origId) const;
-
+	//int recursionCheck(const std::string& origId) const;
 public:
 	Signal(const std::string& id, const std::string& event, std::vector<std::string>& depends, const std::string& unit, double frequency, CtlActionT* onReceived, json_object* getSignalsArgs);
 	Signal(const std::string& id, std::vector<std::string>& depends, const std::string& unit, double frequency, CtlActionT* onReceived);
@@ -65,7 +67,7 @@ public:
 	json_object* toJSON() const;
 
 	void set(long long int timestamp, struct SignalValue& value);
-	void update(long long int timestamp,  struct SignalValue value);
+	void update(Signal* sig);
 	int onReceivedCB(json_object *queryJ);
 	void attachToSourceSignals(Composer& composer);
 
@@ -73,5 +75,5 @@ public:
 	double minimum(int seconds = 0) const;
 	double maximum(int seconds = 0) const;
 	struct SignalValue last() const;
-	int recursionCheck() const;
+	//int recursionCheck() const;
 };