make SalLayoutGlyphs work with MultiSalLayout

Code that needs to lay out texts repeatedly can cache the result
of SalLayout::GetGlyphs() can reuse it. But GetGlyphs() returns
nullptr for MultiSalLayout, so caching for it doesn't work. Worse
still, it actually increases the number of layout calls, because
there's the initial layout for caching and then each call
will need to do the layout again because of the nullptr that's
not cached.

This commit changes SalLayoutGlyphs to possibly include multiple
SalLayoutGlyphsImpl objects, one for each SalLayout handled
by MultiSalLayout. Changes include making GenericSalLayout
work directly with the Impl class, which avoids an indirection
and simplifies code.

Change-Id: Ic4b19934a8a06d4955b51527fe3777c5e91107b2
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/112590
Tested-by: Jenkins
Reviewed-by: Luboš Luňák <l.lunak@collabora.com>

3 files changed, 20 insertions, 11 deletions

diff --git a/include/vcl/glyphitem.hxx b/include/vcl/glyphitem.hxx
index 7634bd3a4413..02d783a3e166 100644
--- a/include/vcl/glyphitem.hxx
+++ b/include/vcl/glyphitem.hxx
@@ -23,23 +23,30 @@
 #include <sal/types.h>
 #include <vcl/dllapi.h>
 
+#include <vector>
+
 typedef sal_uInt16 sal_GlyphId;
 
 class SalLayoutGlyphsImpl;
 
 class VCL_DLLPUBLIC SalLayoutGlyphs final
 {
-    friend class SalLayoutGlyphsImpl;
-    SalLayoutGlyphsImpl* m_pImpl;
+    std::vector<SalLayoutGlyphsImpl*> m_pImpls;
 
 public:
-    SalLayoutGlyphs();
-    SalLayoutGlyphs(const SalLayoutGlyphs&);
+    SalLayoutGlyphs() = default;
+    SalLayoutGlyphs(const SalLayoutGlyphs&) = delete;
+    SalLayoutGlyphs(SalLayoutGlyphs&&);
     ~SalLayoutGlyphs();
 
-    SalLayoutGlyphs& operator=(const SalLayoutGlyphs&);
+    SalLayoutGlyphs& operator=(const SalLayoutGlyphs&) = delete;
+    SalLayoutGlyphs& operator=(SalLayoutGlyphs&&);
 
-    SalLayoutGlyphsImpl* Impl() const { return m_pImpl; }
+    SalLayoutGlyphsImpl* Impl(unsigned int nLevel) const
+    {
+        return nLevel < m_pImpls.size() ? m_pImpls[nLevel] : nullptr;
+    }
+    void AppendImpl(SalLayoutGlyphsImpl* pImpl) { m_pImpls.push_back(pImpl); }
 
     bool IsValid() const;
     void Invalidate();
diff --git a/include/vcl/outdev.hxx b/include/vcl/outdev.hxx
index a8d77c77b30e..ce7d54e75689 100644
--- a/include/vcl/outdev.hxx
+++ b/include/vcl/outdev.hxx
@@ -1352,11 +1352,13 @@ public:
                                                          SalLayoutFlags flags = SalLayoutFlags::NONE,
                                                          vcl::TextLayoutCache const* = nullptr) const;
     SAL_DLLPRIVATE std::unique_ptr<SalLayout>
-                                ImplGlyphFallbackLayout( std::unique_ptr<SalLayout>, ImplLayoutArgs& ) const;
+                                ImplGlyphFallbackLayout( std::unique_ptr<SalLayout>,
+                                                         ImplLayoutArgs&,
+                                                         const SalLayoutGlyphs* ) const;
     SAL_DLLPRIVATE std::unique_ptr<SalLayout>
                                 getFallbackLayout(
                                     LogicalFontInstance* pLogicalFont, int nFallbackLevel,
-                                    ImplLayoutArgs& rLayoutArgs) const;
+                                    ImplLayoutArgs& rLayoutArgs, const SalLayoutGlyphs* ) const;
 
 
     // Enabling/disabling RTL only makes sense for OutputDevices that use a mirroring SalGraphicsLayout
diff --git a/include/vcl/vcllayout.hxx b/include/vcl/vcllayout.hxx
index 7d53d12bd40b..e09e54f59d65 100644
--- a/include/vcl/vcllayout.hxx
+++ b/include/vcl/vcllayout.hxx
@@ -24,13 +24,13 @@
 #include <tools/gen.hxx>
 #include <tools/degree.hxx>
 #include <vcl/devicecoordinate.hxx>
+#include <vcl/glyphitem.hxx>
 #include <vcl/dllapi.h>
 
 class ImplLayoutArgs;
 class PhysicalFontFace;
 class SalGraphics;
 class GlyphItem;
-class SalLayoutGlyphs;
 
 // all positions/widths are in font units
 // one exception: drawposition is in pixel units
@@ -73,7 +73,7 @@ public:
     const Point&    DrawOffset() const                      { return maDrawOffset; }
     Point           GetDrawPosition( const Point& rRelative = Point(0,0) ) const;
 
-    virtual bool    LayoutText( ImplLayoutArgs&, const SalLayoutGlyphs* ) = 0;  // first step of layouting
+    virtual bool    LayoutText( ImplLayoutArgs&, const SalLayoutGlyphsImpl* ) = 0;  // first step of layouting
     virtual void    AdjustLayout( ImplLayoutArgs& );    // adjusting after fallback etc.
     virtual void    InitFont() const {}
     virtual void    DrawText( SalGraphics& ) const = 0;
@@ -94,7 +94,7 @@ public:
     virtual bool GetOutline(basegfx::B2DPolyPolygonVector&) const;
     bool GetBoundRect(tools::Rectangle&) const;
 
-    virtual const SalLayoutGlyphs* GetGlyphs() const;
+    virtual SalLayoutGlyphs GetGlyphs() const;
 
 protected:
     // used by layout engines