This patch contains two new very small utility classes:

  1. base/inc/TRedirectOutputGuard.h

     Very simple guard class for RedirectOutput (similar to TLockGuard)
     to redirect the output to a file. Usage:

     void redir() {
        TRedirectOutputGuard guard("/tmp/pippo.txt","w");
        Printf("Here we go ...");
        cout << "Me too!" << endl;
     }

     If the file does not exist it is created. The mode has the same meaning
     as in TSystem::RedirectOutput(). When the guard object goes out of scope
     the redirection is restored to stdout and stderr, this is exception
     safe.

  2. gui/inc/TGRedirectOutputGuard.h, gui/src/TGRedirectOutputGuard.cxx

     Same functionality but with a text frame window. Usage:

     #include "TGTextView.h"

     void guiredir(TGTextView *tv, const char *fout, const char *mode) {
        TGRedirectOutputGuard guard(tv, fout, mode);
        Printf("Here we go ...");
        cout << "Me too!" << endl;
     }

     where 'tv' is a TGTextView object initialized by the caller; optionally
     one can save the logs into a file.


git-svn-id: http://root.cern.ch/svn/root/trunk@12928 27541ba8-7e3a-0410-8455-c3a389f83636