//===-- TTYState.cpp --------------------------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//  Created by Greg Clayton on 3/26/07.
//
//===----------------------------------------------------------------------===//

#include "TTYState.h"
#include <fcntl.h>
#include <unistd.h>
#include <sys/signal.h>

TTYState::TTYState() :
    m_fd(-1),
    m_tflags(-1),
    m_ttystateErr(-1),
    m_processGroup(-1)
{
}

TTYState::~TTYState()
{
}

bool
TTYState::GetTTYState (int fd, bool saveProcessGroup)
{
    if (fd >= 0 && ::isatty (fd))
    {
        m_fd = fd;
        m_tflags = fcntl (fd, F_GETFL, 0);
        m_ttystateErr = tcgetattr (fd, &m_ttystate);
        if (saveProcessGroup)
            m_processGroup = tcgetpgrp (0);
        else
            m_processGroup = -1;
    }
    else
    {
        m_fd = -1;
        m_tflags = -1;
        m_ttystateErr = -1;
        m_processGroup = -1;
    }
    return m_ttystateErr == 0;
}

bool
TTYState::SetTTYState () const
{
    int result = 0;
    if (IsValid())
    {
        if (TFlagsValid())
            result = fcntl (m_fd, F_SETFL, m_tflags);

        if (TTYStateValid())
            result = tcsetattr (m_fd, TCSANOW, &m_ttystate);

        if (ProcessGroupValid())
        {
            // Save the original signal handler.
            void (*saved_sigttou_callback) (int) = NULL;
            saved_sigttou_callback = (void (*)(int)) signal (SIGTTOU, SIG_IGN);
            // Set the process group
            result = tcsetpgrp (m_fd, m_processGroup);
            // Restore the original signal handler.
            signal (SIGTTOU, saved_sigttou_callback);
        }
        return true;
    }
    return false;
}


TTYStateSwitcher::TTYStateSwitcher() :
    m_currentState(~0)
{
}

TTYStateSwitcher::~TTYStateSwitcher()
{
}

bool
TTYStateSwitcher::GetState(uint32_t idx, int fd, bool saveProcessGroup)
{
    if (ValidStateIndex(idx))
        return m_ttystates[idx].GetTTYState(fd, saveProcessGroup);
    return false;
}

bool
TTYStateSwitcher::SetState(uint32_t idx) const
{
    if (!ValidStateIndex(idx))
        return false;

    // See if we already are in this state?
    if (ValidStateIndex(m_currentState) && (idx == m_currentState) && m_ttystates[idx].IsValid())
        return true;

    // Set the state to match the index passed in and only update the
    // current state if there are no errors.
    if (m_ttystates[idx].SetTTYState())
    {
        m_currentState = idx;
        return true;
    }

    // We failed to set the state. The tty state was invalid or not
    // initialized.
    return false;
}