some != NULL checks

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@6627 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/html/helpfrm.cpp

@@ -92,6 +92,7 @@ class wxHtmlHelpHashData : public wxObject
     public:
         wxHtmlHelpHashData(int index, wxTreeItemId id) : wxObject()
             { m_Index = index; m_Id = id;}
+        ~wxHtmlHelpHashData() {}
         
         int m_Index;
         wxTreeItemId m_Id;
@@ -1147,7 +1148,10 @@ void wxHtmlHelpFrame::OnToolbar(wxCommandEvent& event)
             {
                 if (m_Printer == NULL) 
                     m_Printer = new wxHtmlEasyPrinting(_("Help Printing"), this);
-                m_Printer -> PrintFile(m_HtmlWin -> GetOpenedPage());
+                if (!m_HtmlWin -> GetOpenedPage())
+                    wxLogWarning(_("Cannot print empty page."));
+                else
+                    m_Printer -> PrintFile(m_HtmlWin -> GetOpenedPage());
             }
             break;
 #endif

src/html/htmprint.cpp

@@ -266,6 +266,13 @@ void wxHtmlPrintout::SetHtmlFile(const wxString& htmlfile)
 {
     wxFileSystem fs;
     wxFSFile *ff = fs.OpenFile(htmlfile);
+    
+    if (ff == NULL)
+    {   
+        wxLogError(htmlfile + _(": file does not exist!"));
+        return;
+    }
+    
     wxInputStream *st = ff -> GetStream();
     char *t = new char[st -> GetSize() + 1];
     st -> Read(t, st -> GetSize());