unotools: don't go belly-up if temp dir is wrong or empty

When a wrong temp directory was set (e.g. wrong path in xcu ist set),
you get a assert in the LO-Debug Version, this patch avoid this assertion.

Change-Id: I192f682860ad9cddf907e4b239eff36b4bd6072d
Reviewed-on: https://gerrit.libreoffice.org/46846Reviewed-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>
Tested-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>

sal/CppunitTest_sal_osl.mk

@@ -27,6 +27,7 @@ $(eval $(call gb_CppunitTest_add_exception_objects,sal_osl,\
 
 $(eval $(call gb_CppunitTest_use_libraries,sal_osl,\
 	sal \
+	utl \
 ))
 
 # the test uses the library created by Module_DLL

sal/qa/osl/file/osl_old_test_file.cxx

@@ -32,6 +32,9 @@
 #include <cppunit/extensions/HelperMacros.h>
 #include <cppunit/plugin/TestPlugIn.h>
 
+#include <unotools/tempfile.hxx>
+
+
 namespace osl_test_file
 {
 
@@ -137,8 +140,30 @@ void oldtestfile::test_file_004()
 #endif
 }
 
+class TempFileTest : public CppUnit::TestFixture
+{
+
+public:
+    TempFileTest() {}
+
+    void SetTempNameBaseDirectory()
+    {   // only testing: of not found the directory
+        OUString path = utl::TempFile::SetTempNameBaseDirectory("file:///not/found/dir");
+
+        CPPUNIT_ASSERT_MESSAGE("SetTempNameBaseDirectory must give a empty string back",
+            path.isEmpty());
+    }
+
+
+    CPPUNIT_TEST_SUITE(TempFileTest);
+    CPPUNIT_TEST(SetTempNameBaseDirectory);
+    CPPUNIT_TEST_SUITE_END();
+};
+
+
 } // namespace osl_test_file
 
 CPPUNIT_TEST_SUITE_REGISTRATION( osl_test_file::oldtestfile);
+CPPUNIT_TEST_SUITE_REGISTRATION( osl_test_file::TempFileTest);
 
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */

unotools/source/ucbhelper/tempfile.cxx

@@ -57,13 +57,18 @@ namespace utl
 OUString getParentName( const OUString& aFileName )
 {
     sal_Int32 lastIndex = aFileName.lastIndexOf( '/' );
-    OUString aParent = aFileName.copy( 0, lastIndex );
+    OUString aParent;
 
-    if( aParent.endsWith(":") && aParent.getLength() == 6 )
+    if (lastIndex > -1)
+    {
+        aParent = aFileName.copy(0, lastIndex);
+
+        if (aParent.endsWith(":") && aParent.getLength() == 6)
             aParent += "/";
 
-    if( aParent.equalsIgnoreAsciiCase( "file://" ) )
+        if (aParent.equalsIgnoreAsciiCase("file://"))
             aParent = "file:///";
+    }
 
     return aParent;
 }