| 1 | ///////////////////////////////////////////////////////////////////////////// |
| 2 | // Name: snglinst.h |
| 3 | // Purpose: interface of wxSingleInstanceChecker |
| 4 | // Author: wxWidgets team |
| 5 | // RCS-ID: $Id$ |
| 6 | // Licence: wxWindows licence |
| 7 | ///////////////////////////////////////////////////////////////////////////// |
| 8 | |
| 9 | /** |
| 10 | @class wxSingleInstanceChecker |
| 11 | |
| 12 | wxSingleInstanceChecker class allows to check that only a single instance of a |
| 13 | program is running. |
| 14 | |
| 15 | To do it, you should create an object of this class. As long as this object |
| 16 | is alive, calls to wxSingleInstanceChecker::IsAnotherRunning from other |
| 17 | processes will return @true. |
| 18 | |
| 19 | As the object should have the life span as big as possible, it makes sense to |
| 20 | create it either as a global or in wxApp::OnInit. |
| 21 | For example: |
| 22 | |
| 23 | @code |
| 24 | bool MyApp::OnInit() |
| 25 | { |
| 26 | m_checker = new wxSingleInstanceChecker; |
| 27 | if ( m_checker-IsAnotherRunning() ) |
| 28 | { |
| 29 | wxLogError(_("Another program instance is already running, aborting.")); |
| 30 | |
| 31 | delete m_checker; // OnExit() won't be called if we return false |
| 32 | m_checker = NULL; |
| 33 | |
| 34 | return false; |
| 35 | } |
| 36 | |
| 37 | ... more initializations ... |
| 38 | |
| 39 | return true; |
| 40 | } |
| 41 | |
| 42 | int MyApp::OnExit() |
| 43 | { |
| 44 | delete m_checker; |
| 45 | |
| 46 | return 0; |
| 47 | } |
| 48 | @endcode |
| 49 | |
| 50 | Note that by default wxSingleInstanceChecker::CreateDefault() is used to |
| 51 | create the checker meaning that it will be initialized differently for |
| 52 | different users and thus will allow different users to run the application |
| 53 | concurrently which is usually the required behaviour. However if only a |
| 54 | single instance of a program should be running system-wide, you need to |
| 55 | call Create() with a custom name which does @em not include wxGetUserId(). |
| 56 | |
| 57 | This class is implemented for Win32 and Unix platforms (supporting @c fcntl() |
| 58 | system call, but almost all of modern Unix systems do) only. |
| 59 | |
| 60 | @library{wxbase} |
| 61 | @category{appmanagement} |
| 62 | */ |
| 63 | class wxSingleInstanceChecker |
| 64 | { |
| 65 | public: |
| 66 | /** |
| 67 | Default constructor. |
| 68 | |
| 69 | You may call Create() after using it or directly call |
| 70 | IsAnotherRunning() in which case CreateDefault() will be implicitly |
| 71 | used. |
| 72 | */ |
| 73 | wxSingleInstanceChecker(); |
| 74 | |
| 75 | /** |
| 76 | Constructor calling Create(). |
| 77 | |
| 78 | This constructor does exactly the same thing as Create() but doesn't |
| 79 | allow to check for errors. |
| 80 | */ |
| 81 | wxSingleInstanceChecker(const wxString& name, |
| 82 | const wxString& path = wxEmptyString); |
| 83 | |
| 84 | /** |
| 85 | Destructor frees the associated resources. |
| 86 | |
| 87 | Note that it is not virtual, this class is not meant to be used polymorphically. |
| 88 | */ |
| 89 | ~wxSingleInstanceChecker(); |
| 90 | |
| 91 | /** |
| 92 | Initialize the object if it had been created using the default constructor. |
| 93 | |
| 94 | Note that you can't call Create() more than once, so calling it if the |
| 95 | non default ctor had been used is an error. |
| 96 | |
| 97 | @param name |
| 98 | Must be given and be as unique as possible. It is used as the |
| 99 | mutex name under Win32 and the lock file name under Unix. |
| 100 | wxApp::GetAppName() and wxGetUserId() are commonly used to construct |
| 101 | this parameter. |
| 102 | @param path |
| 103 | The path is optional and is ignored under Win32 and used as the |
| 104 | directory to create the lock file in under Unix |
| 105 | (default is wxGetHomeDir()). |
| 106 | |
| 107 | @return |
| 108 | Returns @false if initialization failed, it doesn't mean that |
| 109 | another instance is running -- use IsAnotherRunning() to check for |
| 110 | it. |
| 111 | |
| 112 | @note |
| 113 | One of possible reasons while Create() may fail on Unix is that the lock |
| 114 | file used for checking already exists but was not created by the user. |
| 115 | Therefore applications shouldn't treat failure of this function as fatal |
| 116 | condition, because doing so would open them to the possibility of a |
| 117 | Denial of Service attack. Instead, they should alert the user about |
| 118 | the problem and offer to continue execution without checking if |
| 119 | another instance is running. |
| 120 | */ |
| 121 | bool Create(const wxString& name, |
| 122 | const wxString& path = wxEmptyString); |
| 123 | |
| 124 | /** |
| 125 | Calls Create() with default name. |
| 126 | |
| 127 | This method simply calls Create() with a string composed of |
| 128 | wxApp::GetAppName() and wxGetUserId(). |
| 129 | |
| 130 | Because this method uses wxApp::GetAppName(), it may only be called |
| 131 | after the global application was constructed. |
| 132 | |
| 133 | @since 2.9.1 |
| 134 | */ |
| 135 | bool CreateDefault(); |
| 136 | |
| 137 | /** |
| 138 | Returns @true if another copy of this program is already running and |
| 139 | @false otherwise. |
| 140 | |
| 141 | Notice that if the object was created using the default constructor |
| 142 | Create() hadn't been called before this method, it will call |
| 143 | CreateDefault() automatically. |
| 144 | */ |
| 145 | bool IsAnotherRunning() const; |
| 146 | }; |
| 147 | |