obs/source-factory: Add function to register proxy objects

Proxies allow for older configurations to work fine on newer versions, without having to manually adjust the scene collection to match the new ids at all. Thanks to the migration system we can freely support any number of old versions, as long as we write migration code.

source/common.hpp

@@ -33,12 +33,15 @@
 // Common C++ includes
 #include <algorithm>
 #include <limits>
+#include <map>
 #include <memory>
+#include <set>
 #include <stdexcept>
 #include <string>
 #include <string_view>
 #include <type_traits>
 #include <utility>
+#include <vector>
 
 // Common Plugin includes
 #include "strings.hpp"

source/obs/obs-source-factory.hpp

@@ -25,7 +25,9 @@ namespace obs {
 	template<class _factory, typename _instance>
 	class source_factory {
 		protected:
-		obs_source_info _info = {};
+		obs_source_info                                         _info = {};
+		std::map<std::string, std::shared_ptr<obs_source_info>> _proxies;
+		std::set<std::string>                                   _proxy_names;
 
 		public:
 		source_factory()
@@ -166,6 +168,20 @@ namespace obs {
 			obs_register_source(&_info);
 		}
 
+		void register_proxy(std::string_view name)
+		{
+			auto iter = _proxy_names.emplace(name);
+
+			// Create proxy.
+			std::shared_ptr<obs_source_info> proxy = std::make_shared<obs_source_info>();
+			memcpy(proxy.get(), &_info, sizeof(obs_source_info));
+			proxy->id = iter.first->c_str();
+			proxy->output_flags |= OBS_SOURCE_DEPRECATED;
+			obs_register_source(proxy.get());
+
+			_proxies.emplace(name, proxy);
+		}
+
 		private /* Factory */:
 		static const char* _get_name(void* type_data) noexcept
 		try {
@@ -509,7 +525,7 @@ namespace obs {
 		public:
 		virtual const char* get_name()
 		{
-			return "Not Implemented Yet";
+			return "Not Yet Implemented";
 		}
 
 		virtual void* create(obs_data_t* settings, obs_source_t* source)