tdf#94006 - re-factor to use rtl::Reference for OpenGLContexts.

Don't use rtl::Reference for the global / list state, so the
ref-count reflects the number of real users.
Hold a reference during ~OpenGLContext.

Change-Id: I4e57a7246159acd58ae7d5a0dfc8704b9795c894

3 files changed, 15 insertions, 47 deletions

diff --git a/vcl/source/app/svdata.cxx b/vcl/source/app/svdata.cxx
index bfc2bb402ee7..ca815a2f3103 100644
--- a/vcl/source/app/svdata.cxx
+++ b/vcl/source/app/svdata.cxx
@@ -140,15 +140,9 @@ vcl::Window* ImplGetDefaultWindow()
             pSVData->mpDefaultWin->SetText( OUString( "VCL ImplGetDefaultWindow"  ) );
 
             // Add a reference to the default context so it never gets deleted
-            OpenGLContext* pContext = pSVData->mpDefaultWin->GetGraphics()->GetOpenGLContext();
-            if( pContext )
-            {
-#ifdef DBG_UTIL
-                pContext->AddRef(NULL);
-#else
-                pContext->AddRef();
-#endif
-            }
+            rtl::Reference<OpenGLContext> pContext = pSVData->mpDefaultWin->GetGraphics()->GetOpenGLContext();
+            if( pContext.is() )
+                pContext->acquire();
         }
         Application::GetSolarMutex().release();
     }
diff --git a/vcl/source/gdi/salgdilayout.cxx b/vcl/source/gdi/salgdilayout.cxx
index 46f76ffb33cc..945f7ae9f687 100644
--- a/vcl/source/gdi/salgdilayout.cxx
+++ b/vcl/source/gdi/salgdilayout.cxx
@@ -76,7 +76,7 @@ SalGraphics::~SalGraphics()
 {
 }
 
-OpenGLContext* SalGraphics::GetOpenGLContext() const
+rtl::Reference<OpenGLContext> SalGraphics::GetOpenGLContext() const
 {
     OpenGLSalGraphicsImpl *pImpl = dynamic_cast<OpenGLSalGraphicsImpl*>(GetImpl());
     if (pImpl)
diff --git a/vcl/source/opengl/OpenGLContext.cxx b/vcl/source/opengl/OpenGLContext.cxx
index df8c6a60c18b..d070e3fb3b6b 100644
--- a/vcl/source/opengl/OpenGLContext.cxx
+++ b/vcl/source/opengl/OpenGLContext.cxx
@@ -58,7 +58,7 @@ OpenGLContext::OpenGLContext():
     mpWindow(NULL),
     m_pChildWindow(NULL),
     mbInitialized(false),
-    mnRefCount(1),
+    mnRefCount(0),
     mbRequestLegacyContext(false),
     mbUseDoubleBufferedRendering(true),
     mnFramebufferCount(0),
@@ -93,6 +93,9 @@ OpenGLContext::OpenGLContext():
 OpenGLContext::~OpenGLContext()
 {
     VCL_GL_INFO("vcl.opengl", "delete context: " << this);
+    assert (mnRefCount == 0);
+
+    mnRefCount = 1; // guard the shutdown paths.
     reset();
 
     ImplSVData* pSVData = ImplGetSVData();
@@ -106,42 +109,13 @@ OpenGLContext::~OpenGLContext()
         pSVData->maGDIData.mpLastContext = mpPrevContext;
 
     m_pChildWindow.disposeAndClear();
+    assert (mnRefCount == 1);
 }
 
-#ifdef DBG_UTIL
-void OpenGLContext::AddRef(SalGraphicsImpl* pImpl)
-{
-    assert(mnRefCount > 0);
-    mnRefCount++;
-
-    maParents.insert(pImpl);
-}
-
-void OpenGLContext::DeRef(SalGraphicsImpl* pImpl)
+rtl::Reference<OpenGLContext> OpenGLContext::Create()
 {
-
-    auto it = maParents.find(pImpl);
-    if(it != maParents.end())
-        maParents.erase(it);
-
-    assert(mnRefCount > 0);
-    if( --mnRefCount == 0 )
-        delete this;
+    return rtl::Reference<OpenGLContext>(new OpenGLContext);
 }
-#else
-void OpenGLContext::AddRef()
-{
-    assert(mnRefCount > 0);
-    mnRefCount++;
-}
-
-void OpenGLContext::DeRef()
-{
-    assert(mnRefCount > 0);
-    if( --mnRefCount == 0 )
-        delete this;
-}
-#endif
 
 void OpenGLContext::requestLegacyContext()
 {
@@ -1337,8 +1311,8 @@ void OpenGLContext::clearCurrent()
 
     // release all framebuffers from the old context so we can re-attach the
     // texture in the new context
-    OpenGLContext* pCurrentCtx = pSVData->maGDIData.mpLastContext;
-    if( pCurrentCtx && pCurrentCtx->isCurrent() )
+    rtl::Reference<OpenGLContext> pCurrentCtx = pSVData->maGDIData.mpLastContext;
+    if( pCurrentCtx.is() && pCurrentCtx->isCurrent() )
         pCurrentCtx->ReleaseFramebuffers();
 }
 
@@ -1348,9 +1322,9 @@ void OpenGLContext::prepareForYield()
 
     // release all framebuffers from the old context so we can re-attach the
     // texture in the new context
-    OpenGLContext* pCurrentCtx = pSVData->maGDIData.mpLastContext;
+    rtl::Reference<OpenGLContext> pCurrentCtx = pSVData->maGDIData.mpLastContext;
 
-    if ( !pCurrentCtx )
+    if ( !pCurrentCtx.is() )
         return;                 // Not using OpenGL
 
     SAL_INFO("vcl.opengl", "Unbinding contexts in preparation for yield");