Merge pull request #2994 from adamreichold/improve-singletons

Continue to simplify and improve singletons

rtgui/cachemanager.cc

@@ -30,18 +30,8 @@
 CacheManager*
 CacheManager::getInstance(void)
 {
-    static CacheManager* instance_ = 0;
-
-    if ( instance_ == 0 ) {
-        static MyMutex smutex_;
-        MyMutex::MyLock lock(smutex_);
-
-        if ( instance_ == 0 ) {
-            instance_ = new CacheManager();
-        }
-    }
-
-    return instance_;
+    static CacheManager instance_;
+    return &instance_;
 }
 
 void CacheManager::init ()

rtgui/editwindow.cc

@@ -24,8 +24,6 @@
 #include "rtimage.h"
 #include "threadutils.h"
 
-static EditWindow* editWnd = NULL;
-
 // Check if the system has more than one display and option is set
 bool EditWindow::isMultiDisplayEnabled()
 {
@@ -35,29 +33,26 @@ bool EditWindow::isMultiDisplayEnabled()
 // Should only be created once, auto-creates window on correct display
 EditWindow* EditWindow::getInstance(RTWindow* p)
 {
+    struct EditWindowInstance
+    {
+        EditWindow editWnd;
 
-    if (editWnd == NULL) {
-        static MyMutex smutex_;
-        MyMutex::MyLock lock(smutex_);
-
-        if ( editWnd == 0 ) {
-            editWnd = new EditWindow(p);
-
+        EditWindowInstance(RTWindow* p) : editWnd(p)
+        {
             // Determine the other display and maximize the window on that
             const Glib::RefPtr< Gdk::Window >& wnd = p->get_window();
             int monNo = p->get_screen()->get_monitor_at_window (wnd);
 
             Gdk::Rectangle lMonitorRect;
-            editWnd->get_screen()->get_monitor_geometry(isMultiDisplayEnabled() ? (monNo == 0 ?  1 : 0) : monNo, lMonitorRect);
-            editWnd->move(lMonitorRect.get_x(), lMonitorRect.get_y());
-            editWnd->maximize();
-            editWnd->show();
-        } else {
-            editWnd->show_all();
+            editWnd.get_screen()->get_monitor_geometry(isMultiDisplayEnabled() ? (monNo == 0 ?  1 : 0) : monNo, lMonitorRect);
+            editWnd.move(lMonitorRect.get_x(), lMonitorRect.get_y());
+            editWnd.maximize();
         }
-    }
+    };
 
-    return editWnd;
+    static EditWindowInstance instance_(p);
+    instance_.editWnd.show_all();
+    return &instance_.editWnd;
 }
 
 EditWindow::EditWindow (RTWindow* p) : parent(p) , isFullscreen(false)

rtgui/extprog.cc

@@ -74,18 +74,8 @@ bool ExtProgAction::Execute(std::vector<Glib::ustring> fileNames)
 // Generates as singleton
 ExtProgStore* ExtProgStore::getInstance()
 {
-    static ExtProgStore* instance_ = 0;
-
-    if ( instance_ == 0 ) {
-        static MyMutex smutex_;
-        MyMutex::MyLock lock(smutex_);
-
-        if ( instance_ == 0 ) {
-            instance_ = new ExtProgStore();
-        }
-    }
-
-    return instance_;
+    static ExtProgStore instance_;
+    return &instance_;
 }
 
 ExtProgStore::~ExtProgStore()

rtgui/previewloader.cc

@@ -168,19 +168,8 @@ PreviewLoader::PreviewLoader():
 
 PreviewLoader* PreviewLoader::getInstance(void)
 {
-    // this will not be deleted...
-    static PreviewLoader* instance_ = NULL;
-
-    if ( instance_ == NULL ) {
-        static MyMutex smutex_;
-        MyMutex::MyLock lock(smutex_);
-
-        if ( instance_ == NULL ) {
-            instance_ = new PreviewLoader();
-        }
-    }
-
-    return instance_;
+    static PreviewLoader instance_;
+    return &instance_;
 }
 
 void PreviewLoader::add(int dir_id, const Glib::ustring& dir_entry, PreviewLoaderListener* l)

rtgui/thumbimageupdater.cc

@@ -192,14 +192,8 @@ public:
 ThumbImageUpdater*
 ThumbImageUpdater::getInstance(void)
 {
-    // this will not be deleted...
-    static ThumbImageUpdater* instance_ = 0;
-
-    if ( instance_ == 0 ) {
-        instance_ = new ThumbImageUpdater();
-    }
-
-    return instance_;
+    static ThumbImageUpdater instance_;
+    return &instance_;
 }
 
 ThumbImageUpdater::ThumbImageUpdater():