Use wxString's empty() when checking if the string is (non-)empty throughout wx.

Instead of constructs such as if "( s.length() )" and "if (s.length() > 0)" use "if ( !s.empty() )" instead. Similarly for "if (s.length() == 0)" or "if ( s.IsNull() )", use "if ( s.empty() )".
No code changes intended except for a few instances where a construct like "if ( s.length() && wxFileExists(s) )" was changed to not check the length of the string and let wxFileExists handle such cases.



git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@66728 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/stringimpl.cpp

@@ -395,14 +395,14 @@ bool wxStringImpl::Alloc(size_t nLen)
 
 wxStringImpl::iterator wxStringImpl::begin()
 {
-    if (length() > 0)
+    if ( !empty() )
         CopyBeforeWrite();
     return m_pchData;
 }
 
 wxStringImpl::iterator wxStringImpl::end()
 {
-    if (length() > 0)
+    if ( !empty() )
         CopyBeforeWrite();
     return m_pchData + length();
 }
@@ -528,7 +528,7 @@ size_t wxStringImpl::rfind(const wxStringImpl& str, size_t nStart) const
     if ( length() >= str.length() )
     {
         // avoids a corner case later
-        if ( length() == 0 && str.length() == 0 )
+        if ( empty() && str.empty() )
             return 0;
 
         // "top" is the point where search starts from