Introduce vcl::IsWindowSystemAvailable()

Change-Id: I6e3f804833db7487ddf7ba75c43d15017dcbe1ba

include/vcl/svapp.hxx

@@ -1706,6 +1706,13 @@ inline void Application::EndYield()
     PostUserEvent( Link() );
 }
 
+namespace vcl
+{
+
+VCL_DLLPUBLIC bool IsWindowSystemAvailable();
+
+}
+
 #endif // _APP_HXX
 
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */

vcl/inc/unx/x11/x11display.hxx

+/* -*- 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/.
+ */
+
+#ifndef INCLUDED_VCL_INC_UNX_X11_X11DISPLAY_HXX
+#define INCLUDED_VCL_INC_UNX_X11_X11DISPLAY_HXX
+
+#include <prex.h>
+#include <X11/Xproto.h>
+#include <postx.h>
+
+#include <rtl/string.hxx>
+
+#include <vcl/dllapi.h>
+
+Display* VCL_DLLPUBLIC OpenX11Display(OString& rDisplay);
+
+#endif // INCLUDED_VCL_INC_UNX_X11_X11DISPLAY_HXX
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */

vcl/osx/salinst.cxx

@@ -1070,4 +1070,15 @@ NSImage* CreateNSImage( const Image& rImage )
     return pImage;
 }
 
+namespace vcl
+{
+
+bool IsWindowSystemAvailable()
+{
+    // Yes I know the parens are not needed. I like them in cases like this. So sue me.
+    return ([NSScreen screens] != nil && [[NSScreen screens] count] > 0);
+}
+
+} // namespace vcl
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */

vcl/unx/generic/app/saldata.cxx

@@ -39,10 +39,6 @@
 #include <sys/time.h>
 #endif
 
-#include <prex.h>
-#include <X11/Xproto.h>
-#include <postx.h>
-
 #include <osl/process.h>
 #include <osl/mutex.hxx>
 
@@ -52,6 +48,7 @@
 #include "unx/sm.hxx"
 #include "unx/i18n_im.hxx"
 #include "unx/i18n_xkb.hxx"
+#include "unx/x11/x11display.hxx"
 #include "salinst.hxx"
 
 #include <osl/signal.h>
@@ -395,53 +392,8 @@ void SalXLib::Init()
     pInputMethod->SetLocale();
     XrmInitialize();
 
-    /*
-     * open connection to X11 Display
-     * try in this order:
-     *  o  -display command line parameter,
-     *  o  $DISPLAY environment variable
-     *  o  default display
-     */
-
-    Display *pDisp = NULL;
-
-    // is there a -display command line parameter?
-
-    sal_uInt32 nParams = osl_getCommandArgCount();
-    OUString aParam;
     OString aDisplay;
-    for (sal_uInt16 i=0; i<nParams; i++)
-    {
-        osl_getCommandArg(i, &aParam.pData);
-        if ( aParam == "-display" )
-        {
-            osl_getCommandArg(i+1, &aParam.pData);
-            aDisplay = OUStringToOString(
-                   aParam, osl_getThreadTextEncoding());
-
-            if ((pDisp = XOpenDisplay(aDisplay.getStr()))!=NULL)
-            {
-                /*
-                 * if a -display switch was used, we need
-                 * to set the environment accoringly since
-                 * the clipboard build another connection
-                 * to the xserver using $DISPLAY
-                 */
-                OUString envVar("DISPLAY");
-                osl_setEnvironment(envVar.pData, aParam.pData);
-            }
-            break;
-        }
-    }
-
-    if (!pDisp && aDisplay.isEmpty())
-    {
-        // Open $DISPLAY or default...
-        char *pDisplay = getenv("DISPLAY");
-        if (pDisplay != NULL)
-            aDisplay = OString(pDisplay);
-        pDisp  = XOpenDisplay(pDisplay);
-    }
+    Display *pDisp = OpenX11Display(aDisplay);
 
     if ( !pDisp )
     {

vcl/unx/generic/gdi/x11windowprovider.cxx

@@ -7,10 +7,82 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+#include <vcl/svapp.hxx>
+
 #include "unx/x11windowprovider.hxx"
+#include "unx/x11/x11display.hxx"
 
 X11WindowProvider::~X11WindowProvider()
 {
 }
 
+Display *OpenX11Display(OString& rDisplay)
+{
+    /*
+     * open connection to X11 Display
+     * try in this order:
+     *  o  -display command line parameter,
+     *  o  $DISPLAY environment variable
+     *  o  default display
+     */
+
+    Display *pDisp = NULL;
+
+    // is there a -display command line parameter?
+
+    sal_uInt32 nParams = osl_getCommandArgCount();
+    OUString aParam;
+    for (sal_uInt16 i=0; i<nParams; i++)
+    {
+        osl_getCommandArg(i, &aParam.pData);
+        if ( aParam == "-display" )
+        {
+            osl_getCommandArg(i+1, &aParam.pData);
+            rDisplay = OUStringToOString(
+                   aParam, osl_getThreadTextEncoding());
+
+            if ((pDisp = XOpenDisplay(rDisplay.getStr()))!=NULL)
+            {
+                /*
+                 * if a -display switch was used, we need
+                 * to set the environment accoringly since
+                 * the clipboard build another connection
+                 * to the xserver using $DISPLAY
+                 */
+                OUString envVar("DISPLAY");
+                osl_setEnvironment(envVar.pData, aParam.pData);
+            }
+            break;
+        }
+    }
+
+    if (!pDisp && rDisplay.isEmpty())
+    {
+        // Open $DISPLAY or default...
+        char *pDisplay = getenv("DISPLAY");
+        if (pDisplay != NULL)
+            rDisplay = OString(pDisplay);
+        pDisp  = XOpenDisplay(pDisplay);
+    }
+
+    return pDisp;
+}
+
+namespace vcl
+{
+
+bool IsWindowSystemAvailable()
+{
+    Display *pDisp;
+    OString aDisplay;
+
+    pDisp = OpenX11Display(aDisplay);
+    if (pDisp)
+        XCloseDisplay(pDisp);
+
+    return (pDisp != nullptr);
+}
+
+} // namespace vcl
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */

vcl/win/source/app/saldata.cxx

@@ -74,4 +74,15 @@ int ImplSalWICompareAscii( const wchar_t* pStr1, const char* pStr2 )
     return nRet;
 }
 
+namespace vcl
+{
+
+bool IsWindowSystemAvailable()
+{
+    return true; // FIXME: we want this to return false if logged in
+                 // to some Cygwin ssh session for instance
+}
+
+} // namespace vcl
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */