redAcore/SelectCore.cpp

/*
 * SelectCore.cpp
 *
 *  Created on: 13 May 2016
 *      Author: wentzelc
 */

// redA Libraries
#include "SelectableCore.h"
#include "TimingCore.h"
#include "LogCore.h"

// Standard C/C++ Libraries
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>

//---------------------------------------------------------------------------

extern char ProcessName[];

//---------------------------------------------------------------------------

// Create Select
CSelect::CSelect( long SelectTimeout, CLogCore * pLog, EDebugLevel pDebugLevel )
{
    // Clear List
    FirstHandle     = NULL;

    // Clear Select sets
    FD_ZERO( &ReadTestFDS );
    FD_ZERO( &WriteTestFDS );

    // Reset maximum File Descriptor
    MaxFD = 0;

    // Set Timeout
    SetInterval( &Timeout, SelectTimeout );

    // Output
    Log = pLog;
    DebugLevel = pDebugLevel;

    // Show status
    if (Log)  Log->Message( DebugLevel, dlLow, "%s: Select - Created", ProcessName );
}
//---------------------------------------------------------------------------

// Destroy Select
CSelect::~CSelect()
{
    TSelectHandle   * NextHandle;

    // Destroy handles
    while (FirstHandle)
    {
        NextHandle = FirstHandle->Next;
        free( FirstHandle );
        FirstHandle = NextHandle;
    }

    // Show status
    if (Log)  Log->Message( DebugLevel, dlLow, "%s: Select - Destroyed", ProcessName );
    return;
}
//---------------------------------------------------------------------------

// Clear Select File Descriptors
void CSelect::Clear()
{
    // Clear Select sets
    FD_ZERO( &ReadTestFDS );
    FD_ZERO( &WriteTestFDS );

    // Reset maximum File Descriptor
    MaxFD = 0;
}
//---------------------------------------------------------------------------

// Add Select File Descriptor
void CSelect::Add( int FD, bool Read, bool Write, CSelectableCore * Function )
{
    TSelectHandle   ** Handle   = NULL;

    // Check if Handle already exists
    Handle = &FirstHandle;
    while (*Handle && ((*Handle)->FD != FD)) {
        Handle = &((*Handle)->Next);
    }

    // Create if not exist
    if (!*Handle) {
        // Create
        *Handle = (TSelectHandle*)malloc( sizeof(TSelectHandle) );
        memset( *Handle, 0, sizeof(TSelectHandle) );

        // Set Parameters
        (*Handle)->FD       = FD;
        (*Handle)->Function = Function;
    }

    // Add Read select
    if (Read && !(*Handle)->Read) {
        (*Handle)->Read = true;
        FD_SET( FD, &ReadTestFDS );

        // Log event
        if (Log)  Log->Message( DebugLevel, dlHigh, "Select: FD [%d] - Add Read", FD );
    }

    // Add Write Select
    if (Write && !(*Handle)->Write) {
        (*Handle)->Write = true;
        FD_SET( FD, &WriteTestFDS );

        // Log event
        if (Log)  Log->Message( DebugLevel, dlHigh, "Select: FD [%d] - Add Write", FD );
    }

    // Check Maximum File Handle
    if (MaxFD <= FD)
        MaxFD = FD+1;
}
//---------------------------------------------------------------------------

void CSelect::Remove( int FD, bool Read, bool Write )
{
    TSelectHandle   ** Handle       = NULL;

    // Check if Handle already exists
    Handle = &FirstHandle;
    while (*Handle && ((*Handle)->FD != FD)) {
        Handle = &((*Handle)->Next);
    }
    // Check if found
    if (!*Handle)
        return;

    // Remove from set for select read check
    if (Read && (*Handle)->Read) {
        (*Handle)->Read = false;
        FD_CLR( FD, &ReadTestFDS);

        // Log event
        if (Log)  Log->Message( DebugLevel, dlHigh, "Select: FD [%d] - Remove Read", FD );
    }

    // Remove from set for select write check
    if (Write && (*Handle)->Write) {
        (*Handle)->Write = false;
        FD_CLR( FD, &WriteTestFDS);

        // Log event
        if (Log)  Log->Message( DebugLevel, dlHigh, "Select: FD [%d] - Remove Write", FD );
    }
    // Handle will be removed in Test() if both Read & Write flags are false
}
//---------------------------------------------------------------------------

bool CSelect::Test()
{
    TSelectHandle   * Handle        = NULL;
    TSelectHandle   ** HandlePtr    = NULL;
    int             TestFD          = 0;
    int             Events          = 0;
    timeval         STimeout        = Timeout;

    // Set Test sets
    ReadFDS     = ReadTestFDS;
    WriteFDS    = WriteTestFDS;

    // Perform select
    Events = select( MaxFD, &ReadFDS, &WriteFDS, (fd_set*)NULL, &STimeout );
    if (Events < 0)
    {
        if (Log)  Log->Message( DebugLevel, dlHigh, "Select: Select operation failed" );
        return false;
    }

    // Check all descriptors for events
    if (Events) {
        Handle = FirstHandle;
        while (Handle)
        {
            // Check if to remove from list
            if (!Handle->Read && !Handle->Write)
            {
                // Update Maximum Test FD
                if (Handle->FD == MaxFD-1) {
                    for (TestFD = MaxFD-1; TestFD >= 0; TestFD--) {
                        if (FD_ISSET( TestFD, &ReadTestFDS ) || FD_ISSET( TestFD, &WriteTestFDS )) {
                            break;
                        }
                    }
                    MaxFD = TestFD+1;
                }

                // Remove from list
                HandlePtr = &FirstHandle;
                while (*HandlePtr && (*HandlePtr != Handle))
                    HandlePtr = &((*HandlePtr)->Next);
                *HandlePtr = (*HandlePtr)->Next;

                // Destroy and go to next
                free( Handle );
                Handle = *HandlePtr;
                continue;
            }
            else
            {
                // Check read Event
                if (FD_ISSET( Handle->FD, &ReadFDS ) && Handle->Function) {
                    Handle->Function->Read( Handle->FD );
                }

                // Check Write Event
                if (FD_ISSET( Handle->FD, &WriteFDS ) && Handle->Function) {
                    Handle->Function->Write( Handle->FD );
                }
            }
            // Next
            Handle = Handle->Next;
        }
    }

    // return success
    return (bool)Events;
}
//---------------------------------------------------------------------------