e725ba4fc2
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@56089 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
120 lines
4.0 KiB
Objective-C
120 lines
4.0 KiB
Objective-C
/////////////////////////////////////////////////////////////////////////////
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// Name: snglinst.h
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// Purpose: interface of wxSingleInstanceChecker
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// Author: wxWidgets team
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// RCS-ID: $Id$
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// Licence: wxWindows license
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/////////////////////////////////////////////////////////////////////////////
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/**
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@class wxSingleInstanceChecker
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wxSingleInstanceChecker class allows to check that only a single instance of a
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program is running.
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To do it, you should create an object of this class. As long as this object
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is alive, calls to wxSingleInstanceChecker::IsAnotherRunning from other
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processes will return @true.
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As the object should have the life span as big as possible, it makes sense to
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create it either as a global or in wxApp::OnInit.
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For example:
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@code
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bool MyApp::OnInit()
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{
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const wxString name = wxString::Format("MyApp-%s", wxGetUserId().c_str());
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m_checker = new wxSingleInstanceChecker(name);
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if ( m_checker-IsAnotherRunning() )
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{
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wxLogError(_("Another program instance is already running, aborting."));
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delete m_checker; // OnExit() won't be called if we return false
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m_checker = NULL;
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return false;
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}
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... more initializations ...
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return true;
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}
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int MyApp::OnExit()
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{
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delete m_checker;
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return 0;
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}
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@endcode
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Note using wxGetUserId() to construct the name: this allows different user
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to run the application concurrently which is usually the intended goal.
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If you don't use the user name in the wxSingleInstanceChecker name, only
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one user would be able to run the application at a time.
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This class is implemented for Win32 and Unix platforms (supporting @c fcntl()
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system call, but almost all of modern Unix systems do) only.
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@library{wxbase}
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@category{misc}
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*/
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class wxSingleInstanceChecker
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{
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public:
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/**
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Default ctor, use Create() after it.
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*/
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wxSingleInstanceChecker();
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/**
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Like Create() but without error checking.
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*/
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wxSingleInstanceChecker(const wxString& name,
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const wxString& path = wxEmptyString);
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/**
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Destructor frees the associated resources.
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Note that it is not virtual, this class is not meant to be used polymorphically.
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*/
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~wxSingleInstanceChecker();
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/**
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Initialize the object if it had been created using the default constructor.
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Note that you can't call Create() more than once, so calling it if the
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@ref wxSingleInstanceChecker() "non default ctor" had been used is an error.
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@param name
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Must be given and be as unique as possible. It is used as the
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mutex name under Win32 and the lock file name under Unix.
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GetAppName() and wxGetUserId() are commonly used to construct
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this parameter.
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@param path
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The path is optional and is ignored under Win32 and used as the
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directory to create the lock file in under Unix
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(default is wxGetHomeDir()).
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@return Returns @false if initialization failed, it doesn't mean that
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another instance is running - use IsAnotherRunning() to check
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for it.
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@note
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One of possible reasons while Create may fail on Unix is that the lock
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file used for checking already exists but was not created by the user.
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Therefore applications shouldn't treat failure of this function as fatal
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condition, because doing so would open them to the possibility of a
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Denial of Service attack. Instead, they should alert the user about
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the problem and offer to continue execution without checking if
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another instance is running.
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*/
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bool Create(const wxString& name,
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const wxString& path = wxEmptyString);
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/**
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Returns @true if another copy of this program is already running, @false
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otherwise.
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*/
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bool IsAnotherRunning() const;
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};
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