Implement Windows VCL backend as plugin

Change-Id: If9c7c67f48311ac68ecc9f8e3a07f9bb7c73d962
Reviewed-on: https://gerrit.libreoffice.org/61101
Tested-by: Jenkins
Reviewed-by: Jan-Marek Glogowski <glogow@fbihome.de>

18 files changed, 349 insertions, 118 deletions

diff --git a/vcl/Library_vcl.mk b/vcl/Library_vcl.mk
index f9df0a3a5f36..095e040154c9 100644
--- a/vcl/Library_vcl.mk
+++ b/vcl/Library_vcl.mk
@@ -731,52 +731,19 @@ endif
 
 ifeq ($(OS),WNT)
 $(eval $(call gb_Library_add_exception_objects,vcl,\
-    vcl/opengl/win/gdiimpl \
     vcl/opengl/win/WinDeviceInfo \
     vcl/opengl/win/blocklist_parser \
-    vcl/win/app/saldata \
-    vcl/win/app/salinfo \
-    vcl/win/app/salinst \
-    vcl/win/app/salshl \
-    vcl/win/app/saltimer \
-    vcl/win/gdi/gdiimpl \
-    vcl/win/gdi/salbmp \
-    vcl/win/gdi/salgdi \
-    vcl/win/gdi/salgdi2 \
-    vcl/win/gdi/salfont \
-    vcl/win/gdi/salgdi_gdiplus \
-    vcl/win/gdi/salnativewidgets-luna \
-    vcl/win/gdi/salprn \
-    vcl/win/gdi/salvd \
-    vcl/win/gdi/winlayout \
-    vcl/win/gdi/DWriteTextRenderer \
-    vcl/win/window/salframe \
-    vcl/win/window/keynames \
-    vcl/win/window/salmenu \
-    vcl/win/window/salobj \
+    vcl/win/app/salplug \
 ))
 
 $(eval $(call gb_Library_use_system_win32_libs,vcl,\
-    advapi32 \
-    crypt32 \
-    gdi32 \
-    gdiplus \
-    imm32 \
-    mpr \
     ole32 \
-    shell32 \
-    usp10 \
-    uuid \
-    version \
-    winspool \
     setupapi \
-    shlwapi \
+    version \
 ))
 
 $(eval $(call gb_Library_add_nativeres,vcl,vcl/salsrc))
-endif
 
-ifeq ($(OS),WNT)
 # HACK: dependency on icon themes so running unit tests don't
 # prevent delivering these by having open file handles on WNT
 $(eval $(call gb_Library_use_package,vcl,postprocess_images))
diff --git a/vcl/Library_vclplug_win.mk b/vcl/Library_vclplug_win.mk
new file mode 100644
index 000000000000..97a83d436cc1
--- /dev/null
+++ b/vcl/Library_vclplug_win.mk
@@ -0,0 +1,98 @@
+# -*- Mode: makefile-gmake; tab-width: 4; indent-tabs-mode: t -*-
+#
+# This file is part of the LibreOffice project.
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+#
+# This file incorporates work covered by the following license notice:
+#
+#   Licensed to the Apache Software Foundation (ASF) under one or more
+#   contributor license agreements. See the NOTICE file distributed
+#   with this work for additional information regarding copyright
+#   ownership. The ASF licenses this file to you under the Apache
+#   License, Version 2.0 (the "License"); you may not use this file
+#   except in compliance with the License. You may obtain a copy of
+#   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+#
+
+$(eval $(call gb_Library_Library,vclplug_win))
+
+$(eval $(call gb_Library_set_include,vclplug_win,\
+    $$(INCLUDE) \
+    -I$(SRCDIR)/vcl/inc \
+    -I$(SRCDIR)/vcl/inc/win \
+))
+
+$(eval $(call gb_Library_add_defs,vclplug_win,\
+    -DVCLPLUG_WIN_IMPLEMENTATION \
+))
+
+$(eval $(call gb_Library_use_custom_headers,vclplug_win,\
+    officecfg/registry \
+))
+
+$(eval $(call gb_Library_use_sdk_api,vclplug_win))
+
+$(eval $(call gb_Library_use_libraries,vclplug_win,\
+    basegfx \
+    comphelper \
+    cppu \
+    i18nlangtag \
+    i18nutil \
+    sal \
+    salhelper \
+    tl \
+    utl \
+    vcl \
+))
+
+$(eval $(call gb_Library_use_externals,vclplug_win,\
+    boost_headers \
+    epoxy \
+    glm_headers \
+    harfbuzz \
+))
+
+$(eval $(call gb_Library_add_exception_objects,vclplug_win,\
+    vcl/opengl/win/gdiimpl \
+    vcl/win/app/saldata \
+    vcl/win/app/salinfo \
+    vcl/win/app/salinst \
+    vcl/win/app/salshl \
+    vcl/win/app/saltimer \
+    vcl/win/gdi/gdiimpl \
+    vcl/win/gdi/salbmp \
+    vcl/win/gdi/salgdi \
+    vcl/win/gdi/salgdi2 \
+    vcl/win/gdi/salfont \
+    vcl/win/gdi/salgdi_gdiplus \
+    vcl/win/gdi/salnativewidgets-luna \
+    vcl/win/gdi/salprn \
+    vcl/win/gdi/salvd \
+    vcl/win/gdi/winlayout \
+    vcl/win/gdi/DWriteTextRenderer \
+    vcl/win/window/salframe \
+    vcl/win/window/keynames \
+    vcl/win/window/salmenu \
+    vcl/win/window/salobj \
+))
+
+$(eval $(call gb_Library_use_system_win32_libs,vclplug_win,\
+    gdi32 \
+    gdiplus \
+    imm32 \
+    ole32 \
+    shell32 \
+    version \
+    winspool \
+))
+
+$(eval $(call gb_Library_add_nativeres,vclplug_win,vcl/salsrc))
+
+# HACK: dependency on icon themes so running unit tests don't
+# prevent delivering these by having open file handles on WNT
+$(eval $(call gb_Library_use_package,vclplug_win,postprocess_images))
+
+# vim: set noet sw=4 ts=4:
diff --git a/vcl/Module_vcl.mk b/vcl/Module_vcl.mk
index b8731614797a..4f8d26c01c4b 100644
--- a/vcl/Module_vcl.mk
+++ b/vcl/Module_vcl.mk
@@ -112,6 +112,7 @@ endif
 ifeq ($(OS),WNT)
 $(eval $(call gb_Module_add_targets,vcl,\
     WinResTarget_vcl \
+    Library_vclplug_win \
 ))
 endif
 
diff --git a/vcl/inc/fontselect.hxx b/vcl/inc/fontselect.hxx
index 9707ba4e5fa9..51f70997ac53 100644
--- a/vcl/inc/fontselect.hxx
+++ b/vcl/inc/fontselect.hxx
@@ -34,7 +34,7 @@ class LogicalFontInstance;
 class PhysicalFontFace;
 class Size;
 
-class FontSelectPattern : public FontAttributes
+class VCL_DLLPUBLIC FontSelectPattern : public FontAttributes
 {
 public:
                     FontSelectPattern( const vcl::Font&, const OUString& rSearchName,
diff --git a/vcl/inc/fontsubset.hxx b/vcl/inc/fontsubset.hxx
index 66368b7cbcb9..76551c29d89d 100644
--- a/vcl/inc/fontsubset.hxx
+++ b/vcl/inc/fontsubset.hxx
@@ -44,7 +44,7 @@ namespace o3tl {
     template<> struct typed_flags<FontType> : is_typed_flags<FontType, (1<<8)-1> {};
 }
 
-class FontSubsetInfo final
+class VCL_DLLPUBLIC FontSubsetInfo final
 {
 public:
     explicit    FontSubsetInfo();
diff --git a/vcl/inc/helpwin.hxx b/vcl/inc/helpwin.hxx
index 09fed59b7138..765dac0508e5 100644
--- a/vcl/inc/helpwin.hxx
+++ b/vcl/inc/helpwin.hxx
@@ -74,7 +74,7 @@ public:
 void ImplShowHelpWindow( vcl::Window* pParent, sal_uInt16 nHelpWinStyle, QuickHelpFlags nStyle,
         const OUString& rHelpText, const OUString& rStatusText,
         const Point& rScreenPos, const tools::Rectangle& rHelpArea );
-void ImplDestroyHelpWindow( bool bUpdateHideTime );
+VCL_DLLPUBLIC void ImplDestroyHelpWindow( bool bUpdateHideTime );
 void ImplSetHelpWindowPos( vcl::Window* pHelpWindow, sal_uInt16 nHelpWinStyle, QuickHelpFlags nStyle,
                             const Point& rPos, const tools::Rectangle& rHelpArea );
 
diff --git a/vcl/inc/opengl/FixedTextureAtlas.hxx b/vcl/inc/opengl/FixedTextureAtlas.hxx
index c273a5e36c0c..145ddf52f5e1 100644
--- a/vcl/inc/opengl/FixedTextureAtlas.hxx
+++ b/vcl/inc/opengl/FixedTextureAtlas.hxx
@@ -16,7 +16,7 @@
 
 struct FixedTexture;
 
-class VCL_PLUGIN_PUBLIC FixedTextureAtlasManager
+class FixedTextureAtlasManager final
 {
     std::vector<std::unique_ptr<FixedTexture>> maFixedTextures;
 
@@ -26,9 +26,13 @@ class VCL_PLUGIN_PUBLIC FixedTextureAtlasManager
 
     void CreateNewTexture();
 
+    FixedTextureAtlasManager( const FixedTextureAtlasManager& ) = delete;
+    FixedTextureAtlasManager& operator=( const FixedTextureAtlasManager& ) = delete;
+
 public:
     FixedTextureAtlasManager(int nWidthFactor, int nHeightFactor, int nTextureSize);
     ~FixedTextureAtlasManager();
+
     OpenGLTexture InsertBuffer(int nWidth, int nHeight, int nFormat, int nType, sal_uInt8 const * pData);
     OpenGLTexture Reserve(int nWidth, int nHeight);
 
diff --git a/vcl/inc/opengl/PackedTextureAtlas.hxx b/vcl/inc/opengl/PackedTextureAtlas.hxx
index 8e6def84c9e4..c7f39d86b4d9 100644
--- a/vcl/inc/opengl/PackedTextureAtlas.hxx
+++ b/vcl/inc/opengl/PackedTextureAtlas.hxx
@@ -26,7 +26,7 @@ struct PackedTexture;
  * [2]: https://github.com/lukaszdk/texture-atlas-generator
  *
  */
-class VCL_PLUGIN_PUBLIC PackedTextureAtlasManager
+class VCL_DLLPUBLIC PackedTextureAtlasManager final
 {
     std::vector<std::unique_ptr<PackedTexture>> maPackedTextures;
 
@@ -35,6 +35,9 @@ class VCL_PLUGIN_PUBLIC PackedTextureAtlasManager
 
     void CreateNewTexture();
 
+    PackedTextureAtlasManager( const PackedTextureAtlasManager& ) = delete;
+    PackedTextureAtlasManager& operator=( const PackedTextureAtlasManager& ) = delete;
+
 public:
 
     /**
@@ -43,6 +46,7 @@ public:
      */
     PackedTextureAtlasManager(int nTextureWidth, int nTextureHeight);
     ~PackedTextureAtlasManager();
+
     OpenGLTexture InsertBuffer(int nWidth, int nHeight, int nFormat, int nType, sal_uInt8 const * pData);
     OpenGLTexture Reserve(int nWidth, int nHeight);
     std::vector<GLuint> ReduceTextureNumber(int nMaxNumberOfTextures);
diff --git a/vcl/inc/salinst.hxx b/vcl/inc/salinst.hxx
index 3ee6aca23567..9f20394fe4e6 100644
--- a/vcl/inc/salinst.hxx
+++ b/vcl/inc/salinst.hxx
@@ -209,7 +209,7 @@ void DestroySalInstance( SalInstance* pInst );
 
 void SalAbort( const OUString& rErrorText, bool bDumpCore );
 
-VCL_PLUGIN_PUBLIC const OUString& SalGetDesktopEnvironment();
+VCL_DLLPUBLIC const OUString& SalGetDesktopEnvironment();
 
 void InitSalData();                         // called from Application-Ctor
 void DeInitSalData();                       // called from Application-Dtor
diff --git a/vcl/inc/salprn.hxx b/vcl/inc/salprn.hxx
index 014f61179b47..d9669793655d 100644
--- a/vcl/inc/salprn.hxx
+++ b/vcl/inc/salprn.hxx
@@ -86,6 +86,9 @@ public:
 
 class VCL_PLUGIN_PUBLIC SalPrinter
 {
+    SalPrinter( const SalPrinter& ) = delete;
+    SalPrinter& operator=( const SalPrinter& ) = delete;
+
 public:
     SalPrinter() {}
     virtual ~SalPrinter();
diff --git a/vcl/inc/salsys.hxx b/vcl/inc/salsys.hxx
index 5e3478e45b2b..fc80e90d0ca9 100644
--- a/vcl/inc/salsys.hxx
+++ b/vcl/inc/salsys.hxx
@@ -83,7 +83,7 @@ public:
 
 };
 
-SalSystem* ImplGetSalSystem();
+VCL_DLLPUBLIC SalSystem* ImplGetSalSystem();
 
 #endif // INCLUDED_VCL_INC_SALSYS_HXX
 
diff --git a/vcl/inc/sft.hxx b/vcl/inc/sft.hxx
index 00cf119a4ca4..95fbcadb0d8d 100644
--- a/vcl/inc/sft.hxx
+++ b/vcl/inc/sft.hxx
@@ -344,7 +344,7 @@ namespace vcl
  * @ingroup sft
  *
  */
-    SFErrCodes CreateTTFromTTGlyphs(TrueTypeFont  *ttf,
+    VCL_DLLPUBLIC SFErrCodes CreateTTFromTTGlyphs(TrueTypeFont  *ttf,
                               const char    *fname,
                               sal_uInt16 const *glyphArray,
                               sal_uInt8 const *encoding,
@@ -387,7 +387,7 @@ namespace vcl
  * @ingroup sft
  *
  */
-    std::unique_ptr<sal_uInt16[]> GetTTSimpleGlyphMetrics(TrueTypeFont const *ttf, const sal_uInt16 *glyphArray, int nGlyphs, bool vertical);
+    VCL_DLLPUBLIC std::unique_ptr<sal_uInt16[]> GetTTSimpleGlyphMetrics(TrueTypeFont const *ttf, const sal_uInt16 *glyphArray, int nGlyphs, bool vertical);
 
 #if defined(_WIN32) || defined(MACOSX) || defined(IOS)
 /**
@@ -399,7 +399,7 @@ namespace vcl
  * @return glyph ID, if the character is missing in the font, the return value is 0.
  * @ingroup sft
  */
-    sal_uInt16 MapChar(TrueTypeFont const *ttf, sal_uInt16 ch);
+    VCL_DLLPUBLIC sal_uInt16 MapChar(TrueTypeFont const *ttf, sal_uInt16 ch);
 #endif
 
 /**
@@ -411,7 +411,7 @@ namespace vcl
  * @ingroup sft
  *
  */
-    void GetTTGlobalFontInfo(TrueTypeFont *ttf, TTGlobalFontInfo *info);
+    VCL_DLLPUBLIC void GetTTGlobalFontInfo(TrueTypeFont *ttf, TTGlobalFontInfo *info);
 
 /**
  * Returns fonts metrics.
@@ -430,7 +430,7 @@ namespace vcl
 /**
  * returns the number of glyphs in a font
  */
- int GetTTGlyphCount( TrueTypeFont const * ttf );
+ VCL_DLLPUBLIC int GetTTGlyphCount( TrueTypeFont const * ttf );
 
 /**
  * provide access to the raw data of a SFNT-container's subtable
diff --git a/vcl/inc/svdata.hxx b/vcl/inc/svdata.hxx
index 6df874abc74b..b36ecf7e6a41 100644
--- a/vcl/inc/svdata.hxx
+++ b/vcl/inc/svdata.hxx
@@ -387,7 +387,7 @@ VCL_PLUGIN_PUBLIC OUString VclResId(const char* pId);
 DockingManager*     ImplGetDockingManager();
 BlendFrameCache*    ImplGetBlendFrameCache();
 
-bool        ImplCallPreNotify( NotifyEvent& rEvt );
+VCL_DLLPUBLIC bool        ImplCallPreNotify( NotifyEvent& rEvt );
 
 VCL_PLUGIN_PUBLIC ImplSVData* ImplGetSVData();
 VCL_PLUGIN_PUBLIC void ImplHideSplash();
diff --git a/vcl/inc/vclpluginapi.h b/vcl/inc/vclpluginapi.h
index e8677d239937..88defd3972d6 100644
--- a/vcl/inc/vclpluginapi.h
+++ b/vcl/inc/vclpluginapi.h
@@ -59,6 +59,12 @@
 #define VCLPLUG_SVP_PUBLIC SAL_DLLPUBLIC_IMPORT
 #endif
 
+#if defined VCLPLUG_WIN_IMPLEMENTATION
+#define VCLPLUG_WIN_PUBLIC SAL_DLLPUBLIC_EXPORT
+#else
+#define VCLPLUG_WIN_PUBLIC SAL_DLLPUBLIC_IMPORT
+#endif
+
 #if defined DESKTOP_DETECTOR_IMPLEMENTATION
 #define DESKTOP_DETECTOR_PUBLIC SAL_DLLPUBLIC_EXPORT
 #else
diff --git a/vcl/source/app/svapp.cxx b/vcl/source/app/svapp.cxx
index ca3848d58a22..bd5127f444c5 100644
--- a/vcl/source/app/svapp.cxx
+++ b/vcl/source/app/svapp.cxx
@@ -1138,8 +1138,7 @@ OUString Application::GetHWOSConfInfo()
         aDetails.append( VclResId(SV_APP_DEFAULT) );
     aDetails.append( "; " );
 
-#ifdef LINUX
-    // Only linux has different backends, so don't show blank for others.
+#if (defined LINUX || defined _WIN32)
     aDetails.append( SV_APP_VCLBACKEND );
     aDetails.append( GetToolkitName() );
     aDetails.append( "; " );
diff --git a/vcl/win/app/salinst.cxx b/vcl/win/app/salinst.cxx
index 1c67113322dc..d5fca66f6bd2 100644
--- a/vcl/win/app/salinst.cxx
+++ b/vcl/win/app/salinst.cxx
@@ -32,6 +32,7 @@
 #include <vcl/opengl/OpenGLHelper.hxx>
 #include <vcl/opengl/OpenGLContext.hxx>
 #include <vcl/timer.hxx>
+#include <vclpluginapi.h>
 
 #include <opengl/salbmp.hxx>
 #include <opengl/win/gdiimpl.hxx>
@@ -299,55 +300,33 @@ SalData::SalData()
 
     SetSalData( this );
     initNWF();
+
+    CoInitialize(nullptr); // put main thread in Single Threaded Apartment (STA)
+    static Gdiplus::GdiplusStartupInput gdiplusStartupInput;
+    Gdiplus::GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, nullptr);
 }
 
 SalData::~SalData()
 {
     deInitNWF();
     SetSalData( nullptr );
-}
-
-void InitSalData()
-{
-    SalData* pSalData = new SalData;
-    CoInitialize(nullptr); // put main thread in Single Threaded Apartment (STA)
-
-    // init GDIPlus
-    static Gdiplus::GdiplusStartupInput gdiplusStartupInput;
-    Gdiplus::GdiplusStartup(&pSalData->gdiplusToken, &gdiplusStartupInput, nullptr);
-}
 
-void DeInitSalData()
-{
     CoUninitialize();
-    SalData* pSalData = GetSalData();
 
-    // deinit GDIPlus
-    if(pSalData)
-    {
-        Gdiplus::GdiplusShutdown(pSalData->gdiplusToken);
-    }
-
-    delete pSalData;
+    if (gdiplusToken)
+        Gdiplus::GdiplusShutdown(gdiplusToken);
 }
 
-void InitSalMain()
+extern "C" {
+VCLPLUG_WIN_PUBLIC SalInstance* create_SalInstance()
 {
-    // remember data, copied from WinMain
-    SalData* pData = GetSalData();
-    if ( pData )    // Im AppServer NULL
-    {
-        STARTUPINFOW aSI;
-        aSI.cb = sizeof( aSI );
-        GetStartupInfoW( &aSI );
-        pData->mhInst    = GetModuleHandleW( nullptr );
-        pData->mnCmdShow = aSI.wShowWindow;
-    }
-}
+    SalData* pSalData = new SalData();
 
-SalInstance* CreateSalInstance()
-{
-    SalData* pSalData = GetSalData();
+    STARTUPINFOW aSI;
+    aSI.cb = sizeof( aSI );
+    GetStartupInfoW( &aSI );
+    pSalData->mhInst = GetModuleHandleW( nullptr );
+    pSalData->mnCmdShow = aSI.wShowWindow;
 
     pSalData->mnAppThreadId = GetCurrentThreadId();
 
@@ -405,20 +384,6 @@ SalInstance* CreateSalInstance()
 
     return pInst;
 }
-
-void DestroySalInstance( SalInstance* pInst )
-{
-    SalData* pSalData = GetSalData();
-
-    //  (only one instance in this version !!!)
-
-    ImplFreeSalGDI();
-
-    // reset instance
-    if ( pSalData->mpInstance == pInst )
-        pSalData->mpInstance = nullptr;
-
-    delete pInst;
 }
 
 WinSalInstance::WinSalInstance()
@@ -426,12 +391,13 @@ WinSalInstance::WinSalInstance()
     , mhComWnd( nullptr )
     , m_nNoYieldLock( 0 )
 {
-    GetYieldMutex()->acquire();
+    ImplSVData* pSVData = ImplGetSVData();
+    pSVData->maAppData.mxToolkitName = OUString("win");
 }
 
 WinSalInstance::~WinSalInstance()
 {
-    GetYieldMutex()->release();
+    ImplFreeSalGDI();
     DestroyWindow( mhComWnd );
 }
 
@@ -1000,12 +966,6 @@ std::shared_ptr<SalBitmap> WinSalInstance::CreateSalBitmap()
         return std::make_shared<WinSalBitmap>();
 }
 
-const OUString& SalGetDesktopEnvironment()
-{
-    static OUString aDesktopEnvironment( "Windows" );
-    return aDesktopEnvironment;
-}
-
 int WinSalInstance::WorkaroundExceptionHandlingInUSER32Lib(int, LPEXCEPTION_POINTERS pExceptionInfo)
 {
     // Decide if an exception is a c++ (mostly UNO) exception or a process violation.
diff --git a/vcl/win/app/salplug.cxx b/vcl/win/app/salplug.cxx
new file mode 100644
index 000000000000..1ef61976a23d
--- /dev/null
+++ b/vcl/win/app/salplug.cxx
@@ -0,0 +1,199 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements. See the NOTICE file distributed
+ *   with this work for additional information regarding copyright
+ *   ownership. The ASF licenses this file to you under the Apache
+ *   License, Version 2.0 (the "License"); you may not use this file
+ *   except in compliance with the License. You may obtain a copy of
+ *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+#include <osl/module.hxx>
+#include <osl/process.h>
+
+#include <rtl/bootstrap.hxx>
+#include <rtl/process.h>
+#include <sal/log.hxx>
+
+#include <salinst.hxx>
+#include <saldatabasic.hxx>
+#include <config_vclplug.h>
+#include <desktop/crashreport.hxx>
+
+#include <cstdio>
+#include <Windows.h>
+
+extern "C" {
+typedef SalInstance*(*salFactoryProc)();
+}
+
+namespace {
+
+// HACK to obtain Application::IsHeadlessModeEnabled early on, before
+// Application::EnableHeadlessMode has potentially been called:
+bool IsHeadlessModeRequested()
+{
+    if (Application::IsHeadlessModeEnabled()) {
+        return true;
+    }
+    sal_uInt32 n = rtl_getAppCommandArgCount();
+    for (sal_uInt32 i = 0; i < n; ++i) {
+        OUString arg;
+        rtl_getAppCommandArg(i, &arg.pData);
+        if ( arg == "--headless" || arg == "-headless" ) {
+            return true;
+        }
+    }
+    return false;
+}
+
+}
+
+static oslModule pCloseModule = nullptr;
+
+static SalInstance* tryInstance( const OUString& rModuleBase, bool bForce = false )
+{
+    SalInstance* pInst = nullptr;
+    OUString aModule(
+#ifdef SAL_DLLPREFIX
+            SAL_DLLPREFIX
+#endif
+            "vclplug_" + rModuleBase + "lo" SAL_DLLEXTENSION );
+
+    osl::Module aMod;
+    if (aMod.loadRelative(reinterpret_cast<oslGenericFunction>(&tryInstance), aModule, SAL_LOADMODULE_GLOBAL))
+    {
+        salFactoryProc aProc = reinterpret_cast<salFactoryProc>(aMod.getFunctionSymbol("create_SalInstance"));
+        if (aProc)
+        {
+            pInst = aProc();
+            SAL_INFO(
+                "vcl.plugadapt",
+                "sal plugin " << aModule << " produced instance " << pInst);
+            if (pInst)
+            {
+                pCloseModule = static_cast<oslModule>(aMod);
+                aMod.release();
+                pCloseModule = nullptr;
+            }
+        }
+        else
+        {
+            SAL_WARN(
+                "vcl.plugadapt",
+                "could not load symbol create_SalInstance from shared object "
+                    << aModule);
+        }
+    }
+    else if (bForce)
+    {
+        SAL_WARN("vcl.plugadapt", "could not load shared object " << aModule);
+    }
+    else
+    {
+        SAL_INFO("vcl.plugadapt", "could not load shared object " << aModule);
+    }
+
+    // coverity[leaked_storage] - this is on purpose
+    return pInst;
+}
+
+SalInstance *CreateSalInstance()
+{
+    SalInstance *pInst = nullptr;
+
+    OUString aUsePlugin;
+    rtl::Bootstrap::get( "SAL_USE_VCLPLUGIN", aUsePlugin );
+
+    if( !aUsePlugin.isEmpty() )
+        pInst = tryInstance( aUsePlugin, true );
+
+    // fallback, try everything
+    static const char* const pPlugin[] = { "win" };
+
+    for ( int i = 0; !pInst && i != SAL_N_ELEMENTS(pPlugin); ++i )
+        pInst = tryInstance( OUString::createFromAscii( pPlugin[ i ] ) );
+
+    if( ! pInst )
+    {
+        std::fprintf( stderr, "no suitable windowing system found, exiting.\n" );
+        _exit( 1 );
+    }
+
+    // acquire SolarMutex
+    pInst->AcquireYieldMutex();
+
+    return pInst;
+}
+
+void DestroySalInstance( SalInstance *pInst )
+{
+    // release SolarMutex
+    pInst->ReleaseYieldMutexAll();
+
+    delete pInst;
+    if( pCloseModule )
+        osl_unloadModule( pCloseModule );
+}
+
+void InitSalData()
+{
+}
+
+void DeInitSalData()
+{
+}
+
+void InitSalMain()
+{
+}
+
+void SalAbort( const OUString& rErrorText, bool bDumpCore )
+{
+    if( rErrorText.isEmpty() )
+        std::fprintf( stderr, "Application Error\n" );
+    else
+    {
+        CrashReporter::AddKeyValue("AbortMessage", rErrorText);
+        std::fprintf( stderr, "%s\n", OUStringToOString(rErrorText, osl_getThreadTextEncoding()).getStr() );
+    }
+    if( bDumpCore )
+        abort();
+    else
+        _exit(1);
+}
+
+const OUString& SalGetDesktopEnvironment()
+{
+    static OUString aDesktopEnvironment( "Windows" );
+    return aDesktopEnvironment;
+}
+
+SalData::SalData() :
+    m_pInstance(nullptr),
+    m_pPIManager(nullptr)
+{
+}
+
+SalData::~SalData() COVERITY_NOEXCEPT_FALSE
+{
+}
+
+bool HasAtHook()
+{
+    BOOL bIsRunning = FALSE;
+    // pvParam must be BOOL
+    return SystemParametersInfoW(SPI_GETSCREENREADER, 0, &bIsRunning, 0)
+        && bIsRunning;
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/vcl/win/window/salframe.cxx b/vcl/win/window/salframe.cxx
index 35da3a0b5f04..d96aa4776fa1 100644
--- a/vcl/win/window/salframe.cxx
+++ b/vcl/win/window/salframe.cxx
@@ -5860,14 +5860,4 @@ bool ImplHandleGlobalMsg( HWND hWnd, UINT nMsg, WPARAM wParam, LPARAM lParam, LR
     return bResult;
 }
 
-#ifdef _WIN32
-bool HasAtHook()
-{
-    BOOL bIsRunning = FALSE;
-    // pvParam must be BOOL
-    return SystemParametersInfoW(SPI_GETSCREENREADER, 0, &bIsRunning, 0)
-        && bIsRunning;
-}
-#endif
-
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */