From 5fc85df38531849aa0d7e0772573dc1d65d8bdb8 Mon Sep 17 00:00:00 2001
From: Ichthyostega <prg@ichthyostega.de>
Date: Thu, 29 Mar 2018 16:57:55 +0200
Subject: [PATCH] DI: inline into lib::Depend to obsolete InstanceHolder

but now we've got two factory functors.
So there is yet more potential for simplification & refactoring
---
 src/lib/depend2.hpp                       | 97 ++++++++++++-----------
 src/lib/format-obj.cpp                    |  2 +-
 tests/library/singleton-subclass-test.cpp |  3 +-
 tests/library/singleton-test.cpp          |  2 +-
 wiki/thinkPad.ichthyo.mm                  | 16 ++++
 5 files changed, 69 insertions(+), 51 deletions(-)

diff --git a/src/lib/depend2.hpp b/src/lib/depend2.hpp
index 179ad53fb..f4eb79f83 100644
--- a/src/lib/depend2.hpp
+++ b/src/lib/depend2.hpp
@@ -105,49 +105,6 @@ namespace lib {
   namespace error = lumiera::error;
   
   
-  namespace { // Implementation helper...
-    
-    using lib::meta::enable_if;
-    
-    template<typename TAR, typename SEL =void>
-    class InstanceHolder
-      : util::NonCopyable
-      {
-        std::unique_ptr<TAR> instance_;
-        
-      public:
-        TAR*
-        buildInstance()
-          {
-            return buildInstance ([]{ return new TAR{}; });
-          }
-        
-        template<class FUN>
-        TAR*
-        buildInstance(FUN&& ctor)
-          {
-            if (instance_)
-              throw error::Fatal("Attempt to double-create a singleton service. "
-                                 "Either the application logic, or the compiler "
-                                 "or runtime system is seriously broken"
-                                ,error::LUMIERA_ERROR_LIFECYCLE);
-            instance_.reset (ctor());
-            return instance_.get();
-          }
-      };
-    
-    template<typename ABS>
-    class InstanceHolder<ABS,  enable_if<std::is_abstract<ABS>>>
-      {
-      public:
-        ABS*
-        buildInstance(...)
-          {
-            throw error::Fatal("Attempt to create a singleton instance of an abstract class. "
-                               "Application architecture or lifecycle is seriously broken.");
-          }
-      };
-  }//(End)Implementation helper
   
   
   
@@ -181,8 +138,6 @@ namespace lib {
       static std::atomic<SRV*> instance;
       static Factory            factory;
       
-      static InstanceHolder<SRV> singleton;
-      
       friend class DependInject<SRV>;
       
       
@@ -204,7 +159,13 @@ namespace lib {
               if (!object)
                 {
                   if (!factory)
-                    object = singleton.buildInstance();
+                    {
+                      object = buildInstance<SRV>();
+                      deleter = []{
+                                    destroy (instance);
+                                    instance = nullptr;
+                                  };
+                    }
                   else
                     object = factory();
                   factory = disabledFactory;
@@ -224,6 +185,48 @@ namespace lib {
           throw error::Fatal("Service not available at this point of the Application Lifecycle"
                             ,error::LUMIERA_ERROR_LIFECYCLE);
         }
+      
+      template<class ABS>
+      static     meta::enable_if<std::is_abstract<ABS>,
+      ABS*                      >
+      buildInstance()
+        {
+          throw error::Fatal("Attempt to create a singleton instance of an abstract class. "
+                             "Application architecture or lifecycle is seriously broken.");
+        }
+      template<class TAR>
+      static     meta::disable_if<std::is_abstract<TAR>,
+      TAR*                      >
+      buildInstance()
+        {
+          return new TAR;
+        }
+      
+      static void
+      destroy (SRV* obj)
+        {
+          if (obj)
+            delete obj;
+        }
+      
+      class Deleter
+        {
+          std::function<void(void)> cleanUp_;
+          
+        public:
+         ~Deleter()
+            {
+              if (cleanUp_)
+                cleanUp_();
+            }
+          template<typename DEL>
+          void operator= (DEL&& fun)
+            {
+              cleanUp_ = std::forward<DEL> (fun);
+            }
+        };
+      
+      static Deleter deleter;
     };
   
   
@@ -237,7 +240,7 @@ namespace lib {
   typename Depend<SRV>::Factory Depend<SRV>::factory;
   
   template<class SRV>
-  InstanceHolder<SRV> Depend<SRV>::singleton;
+  typename Depend<SRV>::Deleter Depend<SRV>::deleter;
   
   
   
diff --git a/src/lib/format-obj.cpp b/src/lib/format-obj.cpp
index 2e6a57848..f2cdc0216 100644
--- a/src/lib/format-obj.cpp
+++ b/src/lib/format-obj.cpp
@@ -306,7 +306,7 @@ apologies for that."
     static regex identifierChars {"[A-Za-z]\\w*", regex::ECMAScript | regex::optimize};
     
     return regex_replace (text, identifierChars, "$&", std::regex_constants::format_no_copy);
-  }
+  }                                                      // don't copy what does not match
   
   
   
diff --git a/tests/library/singleton-subclass-test.cpp b/tests/library/singleton-subclass-test.cpp
index 567308eea..90f9a76e9 100644
--- a/tests/library/singleton-subclass-test.cpp
+++ b/tests/library/singleton-subclass-test.cpp
@@ -66,8 +66,7 @@ namespace test{
       Interface () : TestTargetObj(cnt) {}
       virtual ~Interface() {}
       
-      friend class lib::InstanceHolder<Interface>;
-      friend class std::default_delete<Interface>;
+      friend class lib::Depend<Interface>;
     };
   
   int Interface::cnt = 0;
diff --git a/tests/library/singleton-test.cpp b/tests/library/singleton-test.cpp
index 4a57c7060..6ae29744d 100644
--- a/tests/library/singleton-test.cpp
+++ b/tests/library/singleton-test.cpp
@@ -59,7 +59,7 @@ namespace test{
     protected:
       TargetObj () : TestTargetObj(cnt) {}
       
-      friend class lib::InstanceHolder<TargetObj>;
+      friend class lib::Depend<TargetObj>;
     };
   
   int TargetObj::cnt = 0;
diff --git a/wiki/thinkPad.ichthyo.mm b/wiki/thinkPad.ichthyo.mm
index 412f893c8..fc70113b5 100644
--- a/wiki/thinkPad.ichthyo.mm
+++ b/wiki/thinkPad.ichthyo.mm
@@ -27802,6 +27802,22 @@
 </node>
 </node>
 </node>
+<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1522334796724" ID="ID_1080992734" MODIFIED="1522334873818" TEXT="Funktoren zusammenf&#xfc;hren">
+<icon BUILTIN="flag-yellow"/>
+<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1522334843062" ID="ID_1526236017" MODIFIED="1522334870859" TEXT="DependencyFactory f&#xfc;r">
+<icon BUILTIN="flag-yellow"/>
+<node CREATED="1522334805635" ID="ID_315782435" MODIFIED="1522334817813" TEXT="Erzeugungs-Funktor"/>
+<node CREATED="1522334818473" ID="ID_750129060" MODIFIED="1522334821036" TEXT="Deleter"/>
+<node CREATED="1522334822001" ID="ID_644059909" MODIFIED="1522334935421" TEXT="automatisches Instanz-Management"/>
+</node>
+<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1522334859291" ID="ID_1496044958" MODIFIED="1522334866755" TEXT="einfach konfigurierbar">
+<icon BUILTIN="flag-yellow"/>
+<node CREATED="1522334896942" ID="ID_1215786079" MODIFIED="1522334902129" TEXT="default-Fall"/>
+<node CREATED="1522334903741" ID="ID_1875541619" MODIFIED="1522334911776" TEXT="abstrakte Basisklasse"/>
+<node CREATED="1522334912412" ID="ID_1391948557" MODIFIED="1522334916463" TEXT="custom-Funktor"/>
+<node CREATED="1522334917035" ID="ID_259163474" MODIFIED="1522334922006" TEXT="custom-Deleter"/>
+</node>
+</node>
 </node>
 <node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1521160700669" HGAP="4" ID="ID_978221585" MODIFIED="1521791636399" TEXT="Dokumentation" VSHIFT="25">
 <icon BUILTIN="flag-yellow"/>