//%/////////////////////////////////////////////////////////////////////////////
//
// Copyright (c) 2000, 2001 The Open group, BMC Software, Tivoli Systems, IBM
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to 
// deal in the Software without restriction, including without limitation the 
// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or 
// sell copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// 
// THE ABOVE COPYRIGHT NOTICE AND THIS PERMISSION NOTICE SHALL BE INCLUDED IN 
// ALL COPIES OR SUBSTANTIAL PORTIONS OF THE SOFTWARE. THE SOFTWARE IS PROVIDED
// "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT
// LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR 
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT 
// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN 
// ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
//==============================================================================
//
// Author: Mike Brasher (mbrasher@bmc.com)
//
// Modified By:
//
//%/////////////////////////////////////////////////////////////////////////////

#include "Selector.h"

PEGASUS_NAMESPACE_BEGIN

#define FD_SETSIZE 1024

#include <winsock.h>

using namespace std;

#define DDD(X) // X

////////////////////////////////////////////////////////////////////////////////
//
// Local routines:
//
////////////////////////////////////////////////////////////////////////////////

static inline int select_wrapper(
    int nfds,
    fd_set* rd_fd_set,
    fd_set* wr_fd_set,
    fd_set* ex_fd_set,
    const struct timeval* tv)
{
    return select(FD_SETSIZE, rd_fd_set, wr_fd_set, ex_fd_set, tv);
}

////////////////////////////////////////////////////////////////////////////////
//
// Routines for starting and stoping WinSock:
//
////////////////////////////////////////////////////////////////////////////////

static Uint32 _wsaCount = 0;

static void _WSAInc()
{
    if (_wsaCount == 0)
    {
	WSADATA tmp;

	if (WSAStartup(0x202, &tmp) == SOCKET_ERROR)
	    WSACleanup();
    }

    _wsaCount++;
}

static void _WSADec()
{
    _wsaCount--;

    if (_wsaCount == 0)
	WSACleanup();
}

////////////////////////////////////////////////////////////////////////////////
//
// SelectorRep
//
////////////////////////////////////////////////////////////////////////////////

struct SelectorRep
{
    fd_set rd_fd_set;
    fd_set wr_fd_set;
    fd_set ex_fd_set;
    fd_set active_rd_fd_set;
    fd_set active_wr_fd_set;
    fd_set active_ex_fd_set;
};

////////////////////////////////////////////////////////////////////////////////
//
// Selector
//
////////////////////////////////////////////////////////////////////////////////


Selector::Selector()
{
    _rep = new SelectorRep;
    FD_ZERO(&_rep->rd_fd_set);
    FD_ZERO(&_rep->wr_fd_set);
    FD_ZERO(&_rep->ex_fd_set);
    FD_ZERO(&_rep->active_rd_fd_set);
    FD_ZERO(&_rep->active_wr_fd_set);
    FD_ZERO(&_rep->active_ex_fd_set);
}

Selector::~Selector()
{
    for (Uint32 i = 0, n = _entries.size(); i < n; i++)
	delete _entries[i].handler;

    delete _rep;
}

Boolean Selector::select(Uint32 milliseconds)
{
    // Windows select() has a strange little bug. It returns immediately if
    // there are no descriptors in the set even if the timeout is non-zero.
    // To work around this, we call Sleep() for now:

    if (_entries.size() == 0)
	Sleep(milliseconds);

    // Check for events on the selected file descriptors. Only do this if
    // there were no undispatched events from last time.

    static int count = 0;

    if (count == 0)
    {
	memcpy(&_rep->active_rd_fd_set, &_rep->rd_fd_set, sizeof(fd_set));
	memcpy(&_rep->active_wr_fd_set, &_rep->wr_fd_set, sizeof(fd_set));
	memcpy(&_rep->active_ex_fd_set, &_rep->ex_fd_set, sizeof(fd_set));

	const Uint32 SEC = milliseconds / 1000;
	const Uint32 USEC = (milliseconds % 1000) * 1000;
	struct timeval tv = { SEC, USEC };

	count = select_wrapper(
	    FD_SETSIZE,
	    &_rep->active_rd_fd_set,
	    &_rep->active_wr_fd_set,
	    &_rep->active_ex_fd_set,
	    &tv);

	if (count == 0)
	    return false;
	else if (count == SOCKET_ERROR)
	{
	    count = 0;
	    return false;
	}
    }

    // Dispatch any handler events:

    for (Uint32 i = 0, n = _entries.size(); i < n; i++)
    {
	Sint32 desc = _entries[i].desc;
	Uint32 reasons = 0;
	DDD(cout << "Selector For Loop " << i << endl;)
	if (FD_ISSET(desc, &_rep->active_rd_fd_set))
	    reasons |= READ;

	if (FD_ISSET(desc, &_rep->active_wr_fd_set))
	    reasons |= WRITE;

	if (FD_ISSET(desc, &_rep->active_ex_fd_set))
	    reasons |= EXCEPTION;

	if (reasons)
	{
	    SelectorHandler* handler = _entries[i].handler;
	    DDD(cout << "Reasons = " << reasons << endl;)
	    if (!handler->handle(desc, reasons))
		removeHandler(handler);

	    if (reasons & WRITE)
	    {
		FD_CLR(desc, &_rep->active_wr_fd_set);
	    }

	    if (reasons & EXCEPTION)
	    {
		FD_CLR(desc, &_rep->active_ex_fd_set);
	    }

	    if (reasons & READ)
	    {
		FD_CLR(desc, &_rep->active_rd_fd_set);
	    }

	    count--;
	    return true;
	}
    }

    return false;
}

Boolean Selector::addHandler(
    Sint32 desc,
    Uint32 reasons,
    SelectorHandler* handler)
{
    // See whether a handler is already registered for this one:

    Uint32 pos = _findEntry(desc);

    if (pos != PEG_NOT_FOUND)
	return false;

    // Set the reasons:

    if (reasons & READ)
	FD_SET(desc, &_rep->rd_fd_set);

    if (reasons & WRITE)
	FD_SET(desc, &_rep->wr_fd_set);

    if (reasons & EXCEPTION)
	FD_SET(desc, &_rep->ex_fd_set);

    // Add the entry to the list:

    SelectorEntry entry = { desc, handler };
    _entries.append(entry);

    // Success!

    return true;
}

Boolean Selector::removeHandler(SelectorHandler* handler)
{
    // Look for the given handler and remove it!

    for (Uint32 i = 0, n = _entries.size(); i < n; i++)
    {
	if (_entries[i].handler == handler)
	{
	    Sint32 desc = _entries[i].desc;
	    FD_CLR(desc, &_rep->rd_fd_set);
	    FD_CLR(desc, &_rep->wr_fd_set);
	    FD_CLR(desc, &_rep->ex_fd_set);
	    _entries.remove(i);
	    delete handler;
	    return true;
	}
    }

    // Not found:

    return false;
}

PEGASUS_NAMESPACE_END