src/msw/snglinst.cpp

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