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