src/msw/snglinst.cpp

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // Name:        msw/snglinst.cpp
   3 // Purpose:     implements wxSingleInstanceChecker class for Win32 using
   4 //              named mutexes
   5 // Author:      Vadim Zeitlin
   6 // Modified by:
   7 // Created:     08.06.01
   8 // RCS-ID:      $Id$
   9 // Copyright:   (c) 2001 Vadim Zeitlin <zeitlin@dptmaths.ens-cachan.fr>
  10 // License:     wxWindows licence
  11 ///////////////////////////////////////////////////////////////////////////////
  12
  13 // ============================================================================
  14 // declarations
  15 // ============================================================================
  16
  17 // ----------------------------------------------------------------------------
  18 // headers
  19 // ----------------------------------------------------------------------------
  20
  21 #if defined(__GNUG__) && !defined(NO_GCC_PRAGMA)
  22     #pragma implementation "snglinst.h"
  23 #endif
  24
  25 // For compilers that support precompilation, includes "wx.h".
  26 #include "wx/wxprec.h"
  27
  28 #ifdef __BORLANDC__
  29     #pragma hdrstop
  30 #endif
  31
  32 #if wxUSE_SNGLINST_CHECKER && defined(__WIN32__)
  33
  34 #ifndef WX_PRECOMP
  35     #include "wx/string.h"
  36     #include "wx/log.h"
  37 #endif //WX_PRECOMP
  38
  39 #include "wx/snglinst.h"
  40
  41 #include "wx/msw/private.h"
  42
  43 // ----------------------------------------------------------------------------
  44 // wxSingleInstanceCheckerImpl: the real implementation class
  45 // ----------------------------------------------------------------------------
  46
  47 class WXDLLEXPORT wxSingleInstanceCheckerImpl
  48 {
  49 public:
  50     wxSingleInstanceCheckerImpl()
  51     {
  52         // we don't care about m_wasOpened, it can't be accessed before being
  53         // initialized
  54         m_hMutex = NULL;
  55     }
  56
  57     bool Create(const wxString& name)
  58     {
  59         m_hMutex = ::CreateMutex(NULL, FALSE, name);
  60         if ( !m_hMutex )
  61         {
  62             wxLogLastError(_T("CreateMutex"));
  63
  64             return FALSE;
  65         }
  66
  67         // mutex was either created or opened - see what really happened
  68         m_wasOpened = ::GetLastError() == ERROR_ALREADY_EXISTS;
  69
  70         return TRUE;
  71     }
  72
  73     bool WasOpened() const
  74     {
  75         wxCHECK_MSG( m_hMutex, FALSE,
  76                      _T("can't be called if mutex creation failed") );
  77
  78         return m_wasOpened;
  79     }
  80
  81     ~wxSingleInstanceCheckerImpl()
  82     {
  83         if ( m_hMutex )
  84         {
  85             if ( !::CloseHandle(m_hMutex) )
  86             {
  87                 wxLogLastError(_T("CloseHandle(mutex)"));
  88             }
  89         }
  90     }
  91
  92 private:
  93     // the result of the CreateMutex() call
  94     bool m_wasOpened;
  95
  96     // the mutex handle, may be NULL
  97     HANDLE m_hMutex;
  98
  99     DECLARE_NO_COPY_CLASS(wxSingleInstanceCheckerImpl)
 100 };
 101
 102 // ============================================================================
 103 // wxSingleInstanceChecker implementation
 104 // ============================================================================
 105
 106 bool wxSingleInstanceChecker::Create(const wxString& name,
 107                                      const wxString& WXUNUSED(path))
 108 {
 109     wxASSERT_MSG( !m_impl,
 110                   _T("calling wxSingleInstanceChecker::Create() twice?") );
 111
 112     // creating unnamed mutex doesn't have the same semantics!
 113     wxASSERT_MSG( !name.empty(), _T("mutex name can't be empty") );
 114
 115     m_impl = new wxSingleInstanceCheckerImpl;
 116
 117     return m_impl->Create(name);
 118 }
 119
 120 bool wxSingleInstanceChecker::IsAnotherRunning() const
 121 {
 122     wxCHECK_MSG( m_impl, FALSE, _T("must call Create() first") );
 123
 124     // if the mutex had been opened, another instance is running - otherwise we
 125     // would have created it
 126     return m_impl->WasOpened();
 127 }
 128
 129 wxSingleInstanceChecker::~wxSingleInstanceChecker()
 130 {
 131     delete m_impl;
 132 }
 133
 134 #endif // wxUSE_SNGLINST_CHECKER