//%LICENSE////////////////////////////////////////////////////////////////
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// agreements.  Refer to the OpenPegasusNOTICE.txt file distributed with
// this work for additional information regarding copyright ownership.
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//%/////////////////////////////////////////////////////////////////////////////

#ifndef Pegasus_ServerRunStatus_h
#define Pegasus_ServerRunStatus_h

#ifdef PEGASUS_OS_TYPE_WINDOWS
#include <windows.h>
#endif
#include <Pegasus/Common/Config.h>
#include <Pegasus/Common/String.h>
#include <Service/Linkage.h>

PEGASUS_NAMESPACE_BEGIN

#if defined(PEGASUS_OS_TYPE_WINDOWS)
typedef int PEGASUS_PID_T;
#else
typedef pid_t PEGASUS_PID_T;
#endif

/**
    The ServerRunStatus class is used to manage the run status of a
    server.  It can be used to determine if an instance of the server is
    already running, to kill a running instance, and to indicate that an
    instance is being started.

    The implementation varies per platform.  On Unix platforms, a PID file
    is used to record the process ID of the running server.  On Windows,
    an event handle is used and the PID parameters are not meaningful.
*/
class PEGASUS_SERVICE_LINKAGE ServerRunStatus
{
public:

    /**
        Constructs a ServerRunStatus instance with the specified server
        parameters.
    */
    ServerRunStatus(
        const char* serverName,
        const char* pidFilePath);

    /**
        Destructs the ServerRunStatus instance.  On Windows, this
        indicates to the system that this instance of the server is no
        longer running.
    */
    ~ServerRunStatus();

    /**
        Determines whether the server is running, based on the parameters
        specified in the constructor.
    */
    Boolean isServerRunning();

    /**
        Indicates that this instance of the server is now running.
    */
    void setServerRunning();

    /**
        On platforms that use a PID file, this method allows a parent process
        ID to be specified.  This allows the isServerRunning() method to take
        the parent process into consideration.
    */
    void setParentPid(PEGASUS_PID_T parentPid);

    /**
        Sends a SIGKILL signal to the running server process on platforms
        that support signals.
    */
    Boolean kill();

private:

    /**
        Determines whether the specified process ID is an instance of the
        server specified in the constructor.
    */
    Boolean _isServerProcess(PEGASUS_PID_T pid);

    const char* _serverName;

    /**
        The path to the PID file for this server.  The PID of the server
        process is written to this file by setServerRunning().  The
        isServerRunning() and kill() methods also use this file.
        NOTE: The PID file is not used in the Windows implementation.
    */
    const char* _pidFilePath;

    /**
        Indicates whether this ServerRunStatus instance is for the server that
        is actually running.  A call to setServerRunning() sets this to true.
        If this flag is true when the ServerRunStatus instance is destructed,
        the PID file is removed.
    */
    Boolean _isRunningServerInstance;

    PEGASUS_PID_T _parentPid;

#ifdef PEGASUS_OS_TYPE_WINDOWS
    HANDLE _event;
    Boolean _wasAlreadyRunning;
#endif
};

PEGASUS_NAMESPACE_END

#endif // Pegasus_ServerRunStatus_h
