hold LogicalFontInstance with rtl::Reference

instead of manual reference counting.

Also the releasing of not-currently-in-use LogicalFontInstance objects
from the cache is made less aggressive - we now only flush entries until
we have less than CACHE_SIZE instances, instead of flushing the whole
cache.

Change-Id: Ib235b132776b5f09ae8ae93a933c2eebe5fa9610
Reviewed-on: https://gerrit.libreoffice.org/55384
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

4 files changed, 36 insertions, 137 deletions

diff --git a/vcl/source/font/PhysicalFontFace.cxx b/vcl/source/font/PhysicalFontFace.cxx
index 690fd1fdc401..d356438e43a1 100644
--- a/vcl/source/font/PhysicalFontFace.cxx
+++ b/vcl/source/font/PhysicalFontFace.cxx
@@ -45,7 +45,7 @@ PhysicalFontFace::PhysicalFontFace( const PhysicalFontFace& other )
 {
 }
 
-LogicalFontInstance* PhysicalFontFace::CreateFontInstance(const FontSelectPattern& rFSD) const
+rtl::Reference<LogicalFontInstance> PhysicalFontFace::CreateFontInstance(const FontSelectPattern& rFSD) const
 {
     return new LogicalFontInstance(*this, rFSD);
 }
diff --git a/vcl/source/font/fontcache.cxx b/vcl/source/font/fontcache.cxx
index 205b49ada4e0..a58d9b6931f2 100644
--- a/vcl/source/font/fontcache.cxx
+++ b/vcl/source/font/fontcache.cxx
@@ -83,23 +83,14 @@ bool ImplFontCache::IFSD_Equal::operator()(const FontSelectPattern& rA, const Fo
 }
 
 ImplFontCache::ImplFontCache()
-:   mpLastHitCacheEntry( nullptr ),
-    mnRef0Count( 0 )
+:   mpLastHitCacheEntry( nullptr )
 {}
 
 ImplFontCache::~ImplFontCache()
 {
-    for (auto const& fontInstance : maFontInstanceList)
-    {
-        LogicalFontInstance* pFontInstance = fontInstance.second;
-        if (pFontInstance->mnRefCount)
-            pFontInstance->mpFontCache = nullptr;
-        else
-            delete pFontInstance;
-    }
 }
 
-LogicalFontInstance* ImplFontCache::GetFontInstance( PhysicalFontCollection const * pFontList,
+rtl::Reference<LogicalFontInstance> ImplFontCache::GetFontInstance( PhysicalFontCollection const * pFontList,
     const vcl::Font& rFont, const Size& rSize, float fExactHeight )
 {
     // initialize internal font request object
@@ -107,10 +98,10 @@ LogicalFontInstance* ImplFontCache::GetFontInstance( PhysicalFontCollection cons
     return GetFontInstance( pFontList, aFontSelData );
 }
 
-LogicalFontInstance* ImplFontCache::GetFontInstance( PhysicalFontCollection const * pFontList,
+rtl::Reference<LogicalFontInstance> ImplFontCache::GetFontInstance( PhysicalFontCollection const * pFontList,
     FontSelectPattern& aFontSelData )
 {
-    LogicalFontInstance *pFontInstance = nullptr;
+    rtl::Reference<LogicalFontInstance> pFontInstance;
     PhysicalFontFamily* pFontFamily = nullptr;
 
     // check if a directly matching logical font instance is already cached,
@@ -140,12 +131,7 @@ LogicalFontInstance* ImplFontCache::GetFontInstance( PhysicalFontCollection cons
         }
     }
 
-    if( pFontInstance ) // cache hit => use existing font instance
-    {
-        // increase the font instance's reference count
-        pFontInstance->Acquire();
-    }
-    else if (pFontFamily) // still no cache hit => create a new font instance
+    if( !pFontInstance && pFontFamily) // still no cache hit => create a new font instance
     {
         PhysicalFontFace* pFontData = pFontFamily->FindBestFontFace(aFontSelData);
 
@@ -173,19 +159,38 @@ LogicalFontInstance* ImplFontCache::GetFontInstance( PhysicalFontCollection cons
         }
 #endif
 
+        static const size_t FONTCACHE_MAX = getenv("LO_TESTNAME") ? 1 : 50;
+
+        if (maFontInstanceList.size() >= FONTCACHE_MAX)
+        {
+            // remove entries from font instance cache that are only referenced by the cache
+            FontInstanceList::iterator it_next = maFontInstanceList.begin();
+            while( it_next != maFontInstanceList.end() )
+            {
+                LogicalFontInstance* pFontEntry = (*it_next).second.get();
+                if( pFontEntry->m_nCount > 1 )
+                {
+                    ++it_next;
+                    continue;
+                }
+                maFontInstanceList.erase(it_next);
+                if (mpLastHitCacheEntry == pFontEntry)
+                    mpLastHitCacheEntry = nullptr;
+                // just remove one entry, which will bring us back under FONTCACHE_MAX size again
+                break;
+            }
+        }
+
+        assert(pFontInstance);
         // add the new entry to the cache
-#ifndef NDEBUG
-        auto aResult =
-#endif
-        maFontInstanceList.insert({aFontSelData, pFontInstance});
-        assert(aResult.second);
+        maFontInstanceList.insert({aFontSelData, pFontInstance.get()});
     }
 
-    mpLastHitCacheEntry = pFontInstance;
+    mpLastHitCacheEntry = pFontInstance.get();
     return pFontInstance;
 }
 
-LogicalFontInstance* ImplFontCache::GetGlyphFallbackFont( PhysicalFontCollection const * pFontCollection,
+rtl::Reference<LogicalFontInstance> ImplFontCache::GetGlyphFallbackFont( PhysicalFontCollection const * pFontCollection,
     FontSelectPattern& rFontSelData, int nFallbackLevel, OUString& rMissingCodes )
 {
     // get a candidate font for glyph fallback
@@ -216,102 +221,17 @@ LogicalFontInstance* ImplFontCache::GetGlyphFallbackFont( PhysicalFontCollection
         rFontSelData.maSearchName.clear();
     }
 
-    LogicalFontInstance* pFallbackFont = GetFontInstance( pFontCollection, rFontSelData );
+    rtl::Reference<LogicalFontInstance> pFallbackFont = GetFontInstance( pFontCollection, rFontSelData );
     return pFallbackFont;
 }
 
-void ImplFontCache::Acquire(LogicalFontInstance* pFontInstance)
-{
-    assert(pFontInstance->mpFontCache == this);
-    assert(IsFontInList(pFontInstance) && "ImplFontCache::Acquire() - font absent in the cache");
-
-    if (0 == pFontInstance->mnRefCount++)
-        --mnRef0Count;
-}
-
-void ImplFontCache::Release(LogicalFontInstance* pFontInstance)
-{
-    static const int FONTCACHE_MAX = getenv("LO_TESTNAME") ? 1 : 50;
-
-    assert(pFontInstance->mpFontCache == this);
-    assert(IsFontInList(pFontInstance) && "ImplFontCache::Release() - font absent in the cache");
-    assert(pFontInstance->mnRefCount > 0 && "ImplFontCache::Release() - font refcount underflow");
-    if( --pFontInstance->mnRefCount > 0 )
-        return;
-
-    if (++mnRef0Count < FONTCACHE_MAX)
-        return;
-
-    assert(CountUnreferencedEntries() == mnRef0Count);
-
-    // remove unused entries from font instance cache
-    FontInstanceList::iterator it_next = maFontInstanceList.begin();
-    while( it_next != maFontInstanceList.end() )
-    {
-        LogicalFontInstance* pFontEntry = (*it_next).second;
-        if( pFontEntry->mnRefCount > 0 )
-        {
-            ++it_next;
-            continue;
-        }
-
-        it_next = maFontInstanceList.erase(it_next);
-        delete pFontEntry;
-        --mnRef0Count;
-        assert(mnRef0Count>=0 && "ImplFontCache::Release() - refcount0 underflow");
-
-        if (mpLastHitCacheEntry == pFontEntry)
-            mpLastHitCacheEntry = nullptr;
-    }
-
-    assert(mnRef0Count==0 && "ImplFontCache::Release() - refcount0 mismatch");
-}
-
-bool ImplFontCache::IsFontInList(const LogicalFontInstance* pFont) const
-{
-    auto Pred = [pFont](const FontInstanceList::value_type& el) -> bool { return el.second == pFont; };
-    return std::find_if(maFontInstanceList.begin(), maFontInstanceList.end(), Pred) != maFontInstanceList.end();
-}
-
-int ImplFontCache::CountUnreferencedEntries() const
-{
-    size_t nCount = 0;
-    // count unreferenced entries
-    for (auto const& fontInstance : maFontInstanceList)
-    {
-        const LogicalFontInstance* pFontEntry = fontInstance.second;
-        if (pFontEntry->mnRefCount > 0)
-            continue;
-        ++nCount;
-    }
-    return nCount;
-}
-
 void ImplFontCache::Invalidate()
 {
-    assert(CountUnreferencedEntries() == mnRef0Count);
-
-    // delete unreferenced entries
-    for (auto const& fontInstance : maFontInstanceList)
-    {
-        LogicalFontInstance* pFontEntry = fontInstance.second;
-        if( pFontEntry->mnRefCount > 0 )
-        {
-            // These fonts will become orphans after clearing the list below;
-            // allow them to control their life from now on and wish good luck :)
-            pFontEntry->mpFontCache = nullptr;
-            continue;
-        }
-
-        delete pFontEntry;
-        --mnRef0Count;
-    }
-
     // #112304# make sure the font cache is really clean
     mpLastHitCacheEntry = nullptr;
+    for (auto const & pair : maFontInstanceList)
+        pair.second->mpFontCache = nullptr;
     maFontInstanceList.clear();
-
-    assert(mnRef0Count==0 && "ImplFontCache::Invalidate() - mnRef0Count non-zero");
 }
 
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/vcl/source/font/fontinstance.cxx b/vcl/source/font/fontinstance.cxx
index fca20fd03ca3..e5fac6c6a67b 100644
--- a/vcl/source/font/fontinstance.cxx
+++ b/vcl/source/font/fontinstance.cxx
@@ -48,7 +48,6 @@ LogicalFontInstance::LogicalFontInstance(const PhysicalFontFace& rFontFace, cons
     , mnOrientation( 0 )
     , mbInit( false )
     , mpFontCache( nullptr )
-    , mnRefCount( 1 )
     , m_aFontSelData(rFontSelData)
     , m_pHbFont(nullptr)
     , m_nAveWidthFactor(1.0f)
@@ -115,27 +114,6 @@ void LogicalFontInstance::GetScale(double* nXScale, double* nYScale)
         *nXScale = nWidth / nUPEM;
 }
 
-void LogicalFontInstance::Acquire()
-{
-    assert(mnRefCount < std::numeric_limits<decltype(mnRefCount)>::max()
-        && "LogicalFontInstance::Release() - refcount overflow");
-    if (mpFontCache)
-        mpFontCache->Acquire(this);
-    else
-        ++mnRefCount;
-}
-
-void LogicalFontInstance::Release()
-{
-    assert(mnRefCount > 0 && "LogicalFontInstance::Release() - refcount underflow");
-
-    if (mpFontCache)
-        mpFontCache->Release(this);
-    else
-        if (--mnRefCount == 0)
-            delete this;
-}
-
 void LogicalFontInstance::AddFallbackForUnicode( sal_UCS4 cChar, FontWeight eWeight, const OUString& rFontName )
 {
     if( !mpUnicodeFallbackList )
diff --git a/vcl/source/font/fontselect.cxx b/vcl/source/font/fontselect.cxx
index 80b9ba78ce6b..563c6ebcbc54 100644
--- a/vcl/source/font/fontselect.cxx
+++ b/vcl/source/font/fontselect.cxx
@@ -21,6 +21,7 @@
 #include <o3tl/safeint.hxx>
 
 #include <fontselect.hxx>
+#include <fontinstance.hxx>
 
 #include <PhysicalFontFace.hxx>
 #include <svdata.hxx>