The windows installer now asks to run the uninstaller if an

existing STK installation is found, and will not install
otherwise. This avoids problems when installing a new
stk on top of an older stk installation (e.g. old tracks
might show up in new installation, but not work). 


git-svn-id: svn+ssh://svn.code.sf.net/p/supertuxkart/code/main/trunk@11953 178a84e3-b1eb-0310-8ba1-8eac791a3b58

src/windows_installer/supertuxkart.nsi

@@ -56,12 +56,29 @@
 
   !define MUI_ABORTWARNING
 
+;--------------------------------
+Function validate_dir
+  IfFileExists $INSTDIR\data\*.* 0 return
+    IfFileExists $INSTDIR\Uninstall.exe 0 dont_uninstall
+      MessageBox MB_YESNO "You can't install SuperTuxKart 0.8 in an existing directory. Do you wish to run the uninstaller in $INSTDIR?"  IDNO dont_uninstall
+	; -?=$INSTDIR makes sure that this installer waits for the uninstaller
+	; to finish. The uninstaller (and directory) are not removed, but the
+	; uninstaller will be overwritten by our installer anyway.
+        ExecWait '"$INSTDIR\Uninstall.exe" _?=$INSTDIR'
+        goto return
+    dont_uninstall:
+      MessageBox MB_OK "You can't install SuperTuxKart 0.8 in an existing directory. Please select a new directory."
+      abort
+  return:
+FunctionEnd
 ;--------------------------------
 ;Pages
 
   ;Installer pages
   !insertmacro MUI_PAGE_WELCOME
   !insertmacro MUI_PAGE_LICENSE "SuperTuxKart\License.txt"
+
+  !define MUI_PAGE_CUSTOMFUNCTION_LEAVE validate_dir
   !insertmacro MUI_PAGE_DIRECTORY
 
   ;Start Menu Folder Page Configuration
@@ -92,7 +109,7 @@ Section "Main Section" SecMain
 
   SetOutPath "$INSTDIR"
 
-  ;Adds all the tux kart files
+  ; Adds all SuperTuxKart files
   File /r supertuxkart\*.*
 
   ;Store installation folder