Fixes #10926. Safely teardown MythPainters.

The deadlock was actually the least of our problems.
Since MythPainter::DeleteFormatImagePriv() is a pure
virtual in MythPainter calling ExpireImages() in
the dtor is unsafe. This puts the teardown code
into a Teardown() method which is called from all
the child classes where it is safe to do the teardown.

mythtv/libs/libmythbase/mythversion.h

@@ -12,7 +12,7 @@
 /// Update this whenever the plug-in API changes.
 /// Including changes in the libmythbase, libmyth, libmythtv, libmythav* and
 /// libmythui class methods used by plug-ins.
-#define MYTH_BINARY_VERSION "0.26.20120719-1"
+#define MYTH_BINARY_VERSION "0.26.20120721-1"
 
 /** \brief Increment this whenever the MythTV network protocol changes.
  *

mythtv/libs/libmythui/mythpainter.cpp

@@ -21,20 +21,23 @@ MythPainter::MythPainter()
     SetMaximumCacheSizes(96, 96);
 }
 
-MythPainter::~MythPainter(void)
+void MythPainter::Teardown(void)
 {
-    QMutexLocker locker(&m_allocationLock);
-
     ExpireImages(0);
 
-    if (m_allocatedImages.isEmpty())
-        return;
+    QMutexLocker locker(&m_allocationLock);
 
-    LOG(VB_GENERAL, LOG_WARNING,
-        QString("MythPainter: %1 images not yet de-allocated.")
+    if (!m_allocatedImages.isEmpty())
+    {
+        LOG(VB_GENERAL, LOG_WARNING,
+            QString("MythPainter: %1 images not yet de-allocated.")
             .arg(m_allocatedImages.size()));
-    while (!m_allocatedImages.isEmpty())
-        m_allocatedImages.takeLast()->SetParent(NULL);
+    }
+
+    QSet<MythImage*>::iterator it = m_allocatedImages.begin();
+    for (; it !=  m_allocatedImages.end(); ++it)
+        (*it)->SetParent(NULL);
+    m_allocatedImages.clear();
 }
 
 void MythPainter::SetClipRect(const QRect &)
@@ -506,34 +509,29 @@ MythImage* MythPainter::GetImageFromRect(const QRect &area, int radius,
     return im;
 }
 
-MythImage *MythPainter::GetFormatImage()
+MythImage *MythPainter::GetFormatImage(void)
 {
-    m_allocationLock.lock();
+    QMutexLocker locker(&m_allocationLock);
     MythImage *result = GetFormatImagePriv();
     result->SetFileName("GetFormatImage");
-    m_allocatedImages.append(result);
-    m_allocationLock.unlock();
+    m_allocatedImages.insert(result);
     return result;
 }
 
 void MythPainter::DeleteFormatImage(MythImage *im)
 {
-    m_allocationLock.lock();
+    QMutexLocker locker(&m_allocationLock);
     DeleteFormatImagePriv(im);
-
-    while (m_allocatedImages.contains(im))
-        m_allocatedImages.removeOne(im);
-    m_allocationLock.unlock();
+    m_allocatedImages.remove(im);
 }
 
 void MythPainter::CheckFormatImage(MythImage *im)
 {
     if (im && !im->GetParent())
     {
-        m_allocationLock.lock();
-        m_allocatedImages.append(im);
+        QMutexLocker locker(&m_allocationLock);
+        m_allocatedImages.insert(im);
         im->SetParent(this);
-        m_allocationLock.unlock();
     }
 }
 

mythtv/libs/libmythui/mythpainter.h

@@ -7,6 +7,7 @@
 #include <QWidget>
 #include <QPaintDevice>
 #include <QMutex>
+#include <QSet>
 
 class QRect;
 class QRegion;
@@ -29,7 +30,14 @@ class MUI_PUBLIC MythPainter
 {
   public:
     MythPainter();
-    virtual ~MythPainter();
+    /** MythPainter destructor.
+     *
+     *  The MythPainter destructor does not cleanup, it is unsafe
+     *  to do cleanup in the MythPainter destructor because
+     *  DeleteImagePriv() is a pure virtual in this class. Instead
+     *  children should call MythPainter::Teardown() for cleanup.
+     */
+    virtual ~MythPainter() {}
 
     virtual QString GetName(void) = 0;
     virtual bool SupportsAnimation(void) = 0;
@@ -108,6 +116,10 @@ class MUI_PUBLIC MythPainter
     virtual void DeleteFormatImagePriv(MythImage *im) = 0;
     void ExpireImages(int64_t max = 0);
 
+    // This needs to be called by classes inheriting from MythPainter
+    // in the destructor.
+    virtual void Teardown(void);
+
     void CheckFormatImage(MythImage *im);
 
     QPaintDevice *m_Parent;
@@ -118,8 +130,8 @@ class MUI_PUBLIC MythPainter
     int64_t m_SoftwareCacheSize;
     int64_t m_MaxSoftwareCacheSize;
 
-    QList<MythImage*> m_allocatedImages;
-    QMutex            m_allocationLock;
+    QMutex           m_allocationLock;
+    QSet<MythImage*> m_allocatedImages;
 
     QMap<QString, MythImage *> m_StringToImageMap;
     std::list<QString>         m_StringExpireList;

mythtv/libs/libmythui/mythpainter_d3d9.cpp

@@ -46,7 +46,7 @@ bool MythD3D9Painter::InitD3D9(QPaintDevice *parent)
 
 void MythD3D9Painter::Teardown(void)
 {
-    ExpireImages();
+    MythPainter::Teardown();
     ClearCache();
     DeleteBitmaps();
 

mythtv/libs/libmythui/mythpainter_d3d9.h

@@ -34,8 +34,9 @@ class MUI_PUBLIC MythD3D9Painter : public MythPainter
   protected:
     virtual MythImage* GetFormatImagePriv(void) { return new MythImage(this); }
     virtual void DeleteFormatImagePriv(MythImage *im);
+    virtual void Teardown(void);
+
     bool InitD3D9(QPaintDevice *parent);
-    void Teardown(void);
     void ClearCache(void);
     void DeleteBitmaps(void);
     D3D9Image* GetImageFromCache(MythImage *im);

mythtv/libs/libmythui/mythpainter_ogl.cpp

@@ -31,7 +31,7 @@ MythOpenGLPainter::MythOpenGLPainter(MythRenderOpenGL *render,
 
 MythOpenGLPainter::~MythOpenGLPainter()
 {
-    ExpireImages(0);
+    Teardown();
     FreeResources();
 }
 

mythtv/libs/libmythui/mythpainter_qimage.cpp

@@ -17,7 +17,7 @@ MythQImagePainter::MythQImagePainter() :
 
 MythQImagePainter::~MythQImagePainter()
 {
-    ExpireImages();
+    Teardown();
 }
 
 void MythQImagePainter::Begin(QPaintDevice *parent)

mythtv/libs/libmythui/mythpainter_qt.cpp

@@ -61,6 +61,7 @@ MythQtPainter::MythQtPainter() :
 
 MythQtPainter::~MythQtPainter()
 {
+    Teardown();
     DeletePixmaps();
 }
 

mythtv/libs/libmythui/mythpainter_vdpau.cpp

@@ -52,7 +52,8 @@ bool MythVDPAUPainter::InitVDPAU(QPaintDevice *parent)
 
 void MythVDPAUPainter::Teardown(void)
 {
-    ExpireImages();
+    MythPainter::Teardown();
+
     FreeResources();
 
     m_ImageBitmapMap.clear();

mythtv/libs/libmythui/mythpainter_vdpau.h

@@ -33,9 +33,9 @@ class MUI_PUBLIC MythVDPAUPainter : public MythPainter
   protected:
     virtual MythImage* GetFormatImagePriv(void) { return new MythImage(this); }
     virtual void DeleteFormatImagePriv(MythImage *im);
+    virtual void Teardown(void);
 
     bool InitVDPAU(QPaintDevice *parent);
-    void Teardown(void);
     void ClearCache(void);
     void DeleteBitmaps(void);
     uint GetTextureFromCache(MythImage *im);

mythtv/libs/libmythui/mythpainter_yuva.cpp

@@ -11,6 +11,7 @@ QColor inline rgb_to_yuv(const QColor &original);
 
 MythYUVAPainter::~MythYUVAPainter()
 {
+    Teardown();
     foreach(MythFontProperties* font, m_convertedFonts)
         delete font;
 }