Darwin-Streaming-Server/CommonUtilitiesLib/EventContext.h

/*
 *
 * @APPLE_LICENSE_HEADER_START@
 *
 * Copyright (c) 1999-2008 Apple Inc.  All Rights Reserved.
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this
 * file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
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/*
    File:       EventContext.h

    Contains:   An event context provides the intelligence to take an event
                generated from a UNIX file descriptor (usually EV_RE or EV_WR)
                and signal a Task. 
                    

    
    
*/

#ifndef __EVENT_CONTEXT_H__
#define __EVENT_CONTEXT_H__

#include "OSThread.h"
#include "Task.h"
#include "OSRef.h"

#if MACOSXEVENTQUEUE
    #ifdef AVAILABLE_MAC_OS_X_VERSION_10_5_AND_LATER
        #include <sys/ev.h>
    #else
        #include "ev.h"
    #endif
#else
    #include "ev.h"
#endif


//enable to trace event context execution and the task associated with the context
#define EVENTCONTEXT_DEBUG 0

class EventThread;

class EventContext
{
    public:
    
        //
        // Constructor. Pass in the EventThread you would like to receive
        // events for this context, and the fd that this context applies to
        EventContext(int inFileDesc, EventThread* inThread);
        virtual ~EventContext() { if (fAutoCleanup) this->Cleanup(); }
        
        //
        // InitNonBlocking
        //
        // Sets inFileDesc to be non-blocking. Once this is called, the
        // EventContext object "owns" the file descriptor, and will close it
        // when Cleanup is called. This is necessary because of some weird
        // select() behavior. DON'T CALL CLOSE ON THE FD ONCE THIS IS CALLED!!!!
        void            InitNonBlocking(int inFileDesc);

        //
        // Cleanup. Will be called by the destructor, but can be called earlier
        void            Cleanup();

        //
        // Arms this EventContext. Pass in the events you would like to receive
        void            RequestEvent(int theMask = EV_RE);

        
        //
        // Provide the task you would like to be notified
        void            SetTask(Task* inTask)
        {  
            fTask = inTask; 
            if (EVENTCONTEXT_DEBUG)
            {
                if (fTask== NULL)  
                    qtss_printf("EventContext::SetTask context=%p task= NULL\n", (void *) this); 
                else 
                    qtss_printf("EventContext::SetTask context=%p task= %p name=%s\n",(void *) this,(void *) fTask, fTask->fTaskName); 
            }
        }
        
        // when the HTTP Proxy tunnels takes over a TCPSocket, we need to maintain this context too
        void            SnarfEventContext( EventContext &fromContext );
        
        // Don't cleanup this socket automatically
        void            DontAutoCleanup() { fAutoCleanup = false; }
        
        // Direct access to the FD is not recommended, but is needed for modules
        // that want to use the Socket classes and need to request events on the fd.
        int             GetSocketFD()       { return fFileDesc; }
        
        enum
        {
            kInvalidFileDesc = -1   //int
        };

    protected:

        //
        // ProcessEvent
        //
        // When an event occurs on this file descriptor, this function
        // will get called. Default behavior is to Signal the associated
        // task, but that behavior may be altered / overridden.
        //
        // Currently, we always generate a Task::kReadEvent
		virtual void ProcessEvent(int /*eventBits*/) 
        {   
            if (EVENTCONTEXT_DEBUG)
            {
                if (fTask== NULL)  
                    qtss_printf("EventContext::ProcessEvent context=%p task=NULL\n",(void *) this); 
                else 
                    qtss_printf("EventContext::ProcessEvent context=%p task=%p TaskName=%s\n",(void *)this,(void *) fTask, fTask->fTaskName); 
            }

            if (fTask != NULL)
                fTask->Signal(Task::kReadEvent); 
        }

        int             fFileDesc;

    private:

        struct eventreq fEventReq;
        
        OSRef           fRef;
        PointerSizedInt fUniqueID;
        StrPtrLen       fUniqueIDStr;
        EventThread*    fEventThread;
        Bool16          fWatchEventCalled;
        int             fEventBits;
        Bool16          fAutoCleanup;

        Task*           fTask;
#if DEBUG
        Bool16          fModwatched;
#endif
        
        static unsigned int sUniqueID;
        
        friend class EventThread;
};

class EventThread : public OSThread
{
    public:
    
        EventThread() : OSThread() {}
        virtual ~EventThread() {}
    
    private:
    
        virtual void Entry();
        OSRefTable      fRefTable;
        
        friend class EventContext;
};

#endif //__EVENT_CONTEXT_H__