libcamera: bound_method: Decouple from Signal implementation

To make the BoundMethod classes more generic, replace direct access to
private member from Signal classes with accessors or helper functions.
This allows removal of friend statements from the BoundMethod classes.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>

2 files changed, 12 insertions, 11 deletions

diff --git a/include/libcamera/bound_method.h b/include/libcamera/bound_method.h
index 38c44b92..54c40fc5 100644
--- a/include/libcamera/bound_method.h
+++ b/include/libcamera/bound_method.h
@@ -13,9 +13,6 @@
 namespace libcamera {
 
 class Object;
-template<typename... Args>
-class Signal;
-class SignalBase;
 
 class BoundMethodBase
 {
@@ -28,7 +25,7 @@ public:
 	bool match(T *obj) { return obj == obj_; }
 	bool match(Object *object) { return object == object_; }
 
-	void disconnect(SignalBase *signal);
+	Object *object() const { return object_; }
 
 	void activatePack(void *pack);
 	virtual void invokePack(void *pack) = 0;
@@ -93,6 +90,8 @@ public:
 	BoundMemberMethod(T *obj, Object *object, void (T::*func)(Args...))
 		: BoundMethodArgs<Args...>(obj, object), func_(func) {}
 
+	bool match(void (T::*func)(Args...)) const { return func == func_; }
+
 	void activate(Args... args)
 	{
 		if (this->object_)
@@ -107,7 +106,6 @@ public:
 	}
 
 private:
-	friend class Signal<Args...>;
 	void (T::*func_)(Args...);
 };
 
@@ -118,11 +116,12 @@ public:
 	BoundStaticMethod(void (*func)(Args...))
 		: BoundMethodArgs<Args...>(nullptr, nullptr), func_(func) {}
 
+	bool match(void (*func)(Args...)) const { return func == func_; }
+
 	void activate(Args... args) { (*func_)(args...); }
 	void invoke(Args... args) {}
 
 private:
-	friend class Signal<Args...>;
 	void (*func_)(Args...);
 };
 
diff --git a/include/libcamera/signal.h b/include/libcamera/signal.h
index 3b6de30f..b8a60281 100644
--- a/include/libcamera/signal.h
+++ b/include/libcamera/signal.h
@@ -46,7 +46,9 @@ public:
 	~Signal()
 	{
 		for (BoundMethodBase *slot : slots_) {
-			slot->disconnect(this);
+			Object *object = slot->object();
+			if (object)
+				object->disconnect(this);
 			delete slot;
 		}
 	}
@@ -95,11 +97,11 @@ public:
 			/*
 			 * If the object matches the slot, the slot is
 			 * guaranteed to be a member slot, so we can safely
-			 * cast it to BoundMemberMethod<T, Args...> and access its
-			 * func_ member.
+			 * cast it to BoundMemberMethod<T, Args...> to match
+			 * func.
 			 */
 			if (slot->match(obj) &&
-			    static_cast<BoundMemberMethod<T, Args...> *>(slot)->func_ == func) {
+			    static_cast<BoundMemberMethod<T, Args...> *>(slot)->match(func)) {
 				iter = slots_.erase(iter);
 				delete slot;
 			} else {
@@ -113,7 +115,7 @@ public:
 		for (auto iter = slots_.begin(); iter != slots_.end(); ) {
 			BoundMethodArgs<Args...> *slot = *iter;
 			if (slot->match(nullptr) &&
-			    static_cast<BoundStaticMethod<Args...> *>(slot)->func_ == func) {
+			    static_cast<BoundStaticMethod<Args...> *>(slot)->match(func)) {
 				iter = slots_.erase(iter);
 				delete slot;
 			} else {