From f8f072fb3d784419f357891ae6849241e4ed597f Mon Sep 17 00:00:00 2001
From: Ghislain MARY <ghislain.mary@belledonne-communications.com>
Date: Thu, 14 Sep 2017 11:15:36 +0200
Subject: [PATCH] Handle C back pointer in C++ objects.

---
 src/c-wrapper/c-tools.h        | 42 +++++++++++++++++++++++++++++-----
 src/object/clonable-object-p.h |  4 ++++
 src/object/clonable-object.cpp | 16 +++++++++++++
 src/object/clonable-object.h   |  8 +++++++
 src/variant/variant.h          |  2 +-
 5 files changed, 65 insertions(+), 7 deletions(-)

diff --git a/src/c-wrapper/c-tools.h b/src/c-wrapper/c-tools.h
index 0f4855089..4fbb27a49 100644
--- a/src/c-wrapper/c-tools.h
+++ b/src/c-wrapper/c-tools.h
@@ -22,6 +22,8 @@
 #include <list>
 #include <memory>
 
+#include "variant/variant.h"
+
 // From coreapi.
 #include "private.h"
 
@@ -97,18 +99,21 @@ public:
 	}
 
 	template<typename T>
-	static inline void setCppPtrFromC (void *object, std::shared_ptr<T> &cppPtr) {
+	static inline void setCppPtrFromC (void *object, const std::shared_ptr<T> &cppPtr) {
 		L_ASSERT(object);
 		static_cast<WrappedObject<T> *>(object)->cppPtr = cppPtr;
+		cppPtr->setProperty("LinphonePrivate::Wrapper::cBackPtr", object);
 	}
 
 	template<typename T>
-	static inline void setCppPtrFromC (void *object, T *cppPtr) {
+	static inline void setCppPtrFromC (void *object, const T *cppPtr) {
 		L_ASSERT(object);
-		T *tPtr = reinterpret_cast<T *>(static_cast<WrappedClonableObject<T> *>(object)->cppPtr);
-		if (tPtr != cppPtr) {
-			delete tPtr;
-			static_cast<WrappedClonableObject<T> *>(object)->cppPtr = new T(*cppPtr);
+		T *oldPtr = reinterpret_cast<T *>(static_cast<WrappedClonableObject<T> *>(object)->cppPtr);
+		if (oldPtr != cppPtr) {
+			delete oldPtr;
+			T *cppObject = static_cast<WrappedClonableObject<T> *>(object)->cppPtr;
+			cppObject = new T(*cppPtr);
+			cppObject->setProperty("LinphonePrivate::Wrapper::cBackPtr", object);
 		}
 	}
 
@@ -122,6 +127,28 @@ public:
 		return cppPtr;
 	}
 
+	template<typename CType, typename CppType>
+	static inline CType * getCBackPtr (const std::shared_ptr<CppType> &object, CType *(*cTypeAllocator)()) {
+		Variant v = object->getProperty("LinphonePrivate::Wrapper::cBackPtr");
+		void *value = v.getValue<void *>();
+		if (!value) {
+			CType *cObject = cTypeAllocator();
+			setCppPtrFromC(cObject, object);
+		}
+		return reinterpret_cast<CType *>(value);
+	}
+
+	template<typename CType, typename CppType>
+	static inline CType * getCBackPtr (const CppType *object, CType *(*cTypeAllocator)()) {
+		Variant v = object->getProperty("LinphonePrivate::Wrapper::cBackPtr");
+		void *value = v.getValue<void *>();
+		if (!value) {
+			CType *cObject = cTypeAllocator();
+			setCppPtrFromC(cObject, object);
+		}
+		return reinterpret_cast<CType *>(value);
+	}
+
 	// ---------------------------------------------------------------------------
 
 	template<typename T>
@@ -235,6 +262,9 @@ LINPHONE_END_NAMESPACE
 		L_GET_CPP_PTR_FROM_C_STRUCT(OBJECT, CPP_TYPE, C_TYPE) \
 	))
 
+#define L_GET_C_BACK_PTR(OBJECT, C_TYPE, C_NAME) \
+	LINPHONE_NAMESPACE::Wrapper::getCBackPtr<Linphone ## C_TYPE>(OBJECT, _linphone_ ## C_NAME ## _init)
+
 #define L_GET_C_LIST_FROM_CPP_LIST(LIST, TYPE) \
 	LINPHONE_NAMESPACE::Wrapper::getCListFromCppList<TYPE *>(LIST)
 #define L_GET_CPP_LIST_FROM_C_LIST(LIST, TYPE) \
diff --git a/src/object/clonable-object-p.h b/src/object/clonable-object-p.h
index 7d507599f..87266a2c5 100644
--- a/src/object/clonable-object-p.h
+++ b/src/object/clonable-object-p.h
@@ -23,6 +23,8 @@
 
 #include "linphone/utils/general.h"
 
+#include "variant/variant.h"
+
 // =============================================================================
 
 LINPHONE_BEGIN_NAMESPACE
@@ -41,6 +43,8 @@ private:
 
 	int nRefs = 0;
 
+	std::unordered_map<std::string, Variant> properties;
+
 	L_DECLARE_PUBLIC(ClonableObject);
 
 	// It's forbidden to copy directly one Clonable object private.
diff --git a/src/object/clonable-object.cpp b/src/object/clonable-object.cpp
index 45412dc88..72a9f290d 100644
--- a/src/object/clonable-object.cpp
+++ b/src/object/clonable-object.cpp
@@ -82,4 +82,20 @@ void ClonableObject::setRef (const ClonableObjectPrivate &p) {
 	mPrivate->ref();
 }
 
+Variant ClonableObject::getProperty (const string &name) const {
+	L_D(const ClonableObject);
+	auto it = d->properties.find(name);
+	return it == d->properties.cend() ? Variant() : it->second;
+}
+
+void ClonableObject::setProperty (const string &name, const Variant &value) {
+	L_D(ClonableObject);
+	d->properties[name] = value;
+}
+
+void ClonableObject::setProperty (const string &name, Variant &&value) {
+	L_D(ClonableObject);
+	d->properties[name] = move(value);
+}
+
 LINPHONE_END_NAMESPACE
diff --git a/src/object/clonable-object.h b/src/object/clonable-object.h
index 34d4771c6..e36c5add2 100644
--- a/src/object/clonable-object.h
+++ b/src/object/clonable-object.h
@@ -19,16 +19,24 @@
 #ifndef _CLONABLE_OBJECT_H_
 #define _CLONABLE_OBJECT_H_
 
+#include <string>
+
 #include "linphone/utils/general.h"
 
 // =============================================================================
 
 LINPHONE_BEGIN_NAMESPACE
 
+class Variant;
+
 class LINPHONE_PUBLIC ClonableObject {
 public:
 	virtual ~ClonableObject ();
 
+	Variant getProperty (const std::string &name) const;
+	void setProperty (const std::string &name, const Variant &value);
+	void setProperty (const std::string &name, Variant &&value);
+
 protected:
 	// Use a new ClonableObjectPrivate without owner.
 	explicit ClonableObject (ClonableObjectPrivate &p);
diff --git a/src/variant/variant.h b/src/variant/variant.h
index 2966f79d1..4b1ffe529 100644
--- a/src/variant/variant.h
+++ b/src/variant/variant.h
@@ -82,7 +82,7 @@ public:
 
 	template<typename T, typename = typename std::enable_if<std::is_same<T, void *>::value> >
 	// void* constructor. Must be explicitly called.
-	Variant (T value);
+	Variant (T value) {}
 
 	~Variant ();