[libcamera-devel] [PATCH v4 29/37] libcamera: IPAProxy: Remove registration mechanism

[Paul Elder]

Implementations of IPA proxies use a registration mechanism to register
themselves with the main IPA proxy factory. This registration declares
static objects, causing a risk of things being constructed before the
proper libcamera facilities are ready. Since each pipeline handler has
its own IPA proxy and knows the type, it isn't necessary to have a proxy
factory. Remove it to alleviate the risk of early construction.

Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>

---
No change in v4

No change in v3

Changes in v2:
- remove documentation
---
 include/libcamera/internal/ipa_proxy.h | 29 --------
 src/libcamera/ipa_proxy.cpp            | 93 --------------------------
 2 files changed, 122 deletions(-)

diff --git a/include/libcamera/internal/ipa_proxy.h b/include/libcamera/internal/ipa_proxy.h
index 195d2cb4..f651a3ae 100644
--- a/include/libcamera/internal/ipa_proxy.h
+++ b/include/libcamera/internal/ipa_proxy.h
@@ -36,35 +36,6 @@ private:
 	IPAModule *ipam_;
 };
 
-class IPAProxyFactory
-{
-public:
-	IPAProxyFactory(const char *name);
-	virtual ~IPAProxyFactory() = default;
-
-	virtual std::unique_ptr<IPAProxy> create(IPAModule *ipam, bool isolate) = 0;
-
-	const std::string &name() const { return name_; }
-
-	static void registerType(IPAProxyFactory *factory);
-	static std::vector<IPAProxyFactory *> &factories();
-
-private:
-	std::string name_;
-};
-
-#define REGISTER_IPA_PROXY(proxy)					\
-class proxy##Factory final : public IPAProxyFactory			\
-{									\
-public:									\
-	proxy##Factory() : IPAProxyFactory(#proxy) {}			\
-	std::unique_ptr<IPAProxy> create(IPAModule *ipam, bool isolate)	\
-	{								\
-		return std::make_unique<proxy>(ipam, isolate);		\
-	}								\
-};									\
-static proxy##Factory global_##proxy##Factory;
-
 } /* namespace libcamera */
 
 #endif /* __LIBCAMERA_INTERNAL_IPA_PROXY_H__ */
diff --git a/src/libcamera/ipa_proxy.cpp b/src/libcamera/ipa_proxy.cpp
index ee5e6f3e..29c0e9e0 100644
--- a/src/libcamera/ipa_proxy.cpp
+++ b/src/libcamera/ipa_proxy.cpp
@@ -30,17 +30,11 @@ LOG_DEFINE_CATEGORY(IPAProxy)
  * \brief IPA Proxy
  *
  * Isolate IPA into separate process.
- *
- * Every subclass of proxy shall be registered with libcamera using
- * the REGISTER_IPA_PROXY() macro.
  */
 
 /**
  * \brief Construct an IPAProxy instance
  * \param[in] ipam The IPA module
- *
- * IPAProxy instances shall be constructed through the IPAProxyFactory::create()
- * method implemented by the respective factories.
  */
 IPAProxy::IPAProxy(IPAModule *ipam)
 	: valid_(false), ipam_(ipam)
@@ -219,91 +213,4 @@ std::string IPAProxy::resolvePath(const std::string &file) const
  * construction.
  */
 
-/**
- * \class IPAProxyFactory
- * \brief Registration of IPAProxy classes and creation of instances
- *
- * To facilitate discovery and instantiation of IPAProxy classes, the
- * IPAProxyFactory class maintains a registry of IPAProxy classes. Each
- * IPAProxy subclass shall register itself using the REGISTER_IPA_PROXY()
- * macro, which will create a corresponding instance of a IPAProxyFactory
- * subclass and register it with the static list of factories.
- */
-
-/**
- * \brief Construct a IPAProxy factory
- * \param[in] name Name of the IPAProxy class
- *
- * Creating an instance of the factory registers is with the global list of
- * factories, accessible through the factories() function.
- *
- * The factory \a name is used for debugging and IPAProxy matching purposes
- * and shall be unique.
- */
-IPAProxyFactory::IPAProxyFactory(const char *name)
-	: name_(name)
-{
-	registerType(this);
-}
-
-/**
- * \fn IPAProxyFactory::create()
- * \brief Create an instance of the IPAProxy corresponding to the factory
- * \param[in] ipam The IPA module
- * \param[in] isolate Flag to isolate the IPA module
- *
- * This virtual function is implemented by the REGISTER_IPA_PROXY() macro.
- * It creates a IPAProxy instance that isolates an IPA interface designated
- * by the IPA module \a ipam. If \a isolate is true, then the IPA module will
- * be isolated.
- *
- * \return A pointer to a newly constructed instance of the IPAProxy subclass
- * corresponding to the factory
- */
-
-/**
- * \fn IPAProxyFactory::name()
- * \brief Retrieve the factory name
- * \return The factory name
- */
-
-/**
- * \brief Add a IPAProxy class to the registry
- * \param[in] factory Factory to use to construct the IPAProxy
- *
- * The caller is responsible to guarantee the uniqueness of the IPAProxy name.
- */
-void IPAProxyFactory::registerType(IPAProxyFactory *factory)
-{
-	std::vector<IPAProxyFactory *> &factories = IPAProxyFactory::factories();
-
-	factories.push_back(factory);
-
-	LOG(IPAProxy, Debug)
-		<< "Registered proxy \"" << factory->name() << "\"";
-}
-
-/**
- * \brief Retrieve the list of all IPAProxy factories
- *
- * The static factories map is defined inside the function to ensure it gets
- * initialized on first use, without any dependency on link order.
- *
- * \return The list of pipeline handler factories
- */
-std::vector<IPAProxyFactory *> &IPAProxyFactory::factories()
-{
-	static std::vector<IPAProxyFactory *> factories;
-	return factories;
-}
-
-/**
- * \def REGISTER_IPA_PROXY
- * \brief Register a IPAProxy with the IPAProxy factory
- * \param[in] proxy Class name of IPAProxy derived class to register
- *
- * Register a proxy subclass with the factory and make it available to
- * isolate IPA modules.
- */
-
 } /* namespace libcamera */
-- 
2.27.0