/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing
**
** This file is part of Qt Creator.
**
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company.  For licensing terms and
** conditions see http://www.qt.io/terms-conditions.  For further information
** use the contact form at http://www.qt.io/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 or version 3 as published by the Free
** Software Foundation and appearing in the file LICENSE.LGPLv21 and
** LICENSE.LGPLv3 included in the packaging of this file.  Please review the
** following information to ensure the GNU Lesser General Public License
** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, The Qt Company gives you certain additional
** rights.  These rights are described in The Qt Company LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
****************************************************************************/

#include "windebuginterface.h"

#ifdef Q_OS_WIN

#include <windows.h>


/*!
    \class ProjectExplorer::Internal::WinDebugInterface
    \brief The WinDebugInterface class is used on Windows to capture output of
    the Windows API \c OutputDebugString() function.

    Emits output by process id.

    The \c OutputDebugString() function puts its data into a shared memory segment named
    \c DBWIN_BUFFER which can be accessed via file mapping.
*/

namespace ProjectExplorer {
namespace Internal {

WinDebugInterface *WinDebugInterface::m_instance = 0;

WinDebugInterface *WinDebugInterface::instance()
{
    return m_instance;
}

bool WinDebugInterface::stop()
{
    if (!m_waitHandles[TerminateEventHandle])
        return false;
    SetEvent(m_waitHandles[TerminateEventHandle]);
    return true;
}

WinDebugInterface::WinDebugInterface(QObject *parent) :
    QThread(parent)
{
    m_instance = this;
    setObjectName(QLatin1String("WinDebugInterfaceThread"));
}

WinDebugInterface::~WinDebugInterface()
{
    if (stop())
        wait(500);
    m_instance = 0;
}

void WinDebugInterface::run()
{
    m_waitHandles[DataReadyEventHandle] = m_waitHandles[TerminateEventHandle] = 0;
    m_bufferReadyEvent = 0;
    m_sharedFile = 0;
    m_sharedMem  = 0;
    if (!runLoop())
        emit cannotRetrieveDebugOutput();
    if (m_sharedMem) {
        UnmapViewOfFile(m_sharedMem);
        m_sharedMem = 0;
    }
    if (m_sharedFile) {
        CloseHandle(m_sharedFile);
        m_sharedFile = 0;
    }
    if (m_waitHandles[TerminateEventHandle]) {
        CloseHandle(m_waitHandles[TerminateEventHandle]);
        m_waitHandles[TerminateEventHandle] = 0;
    }
    if (m_waitHandles[DataReadyEventHandle]) {
        CloseHandle(m_waitHandles[DataReadyEventHandle]);
        m_waitHandles[DataReadyEventHandle] = 0;
    }
    if (m_bufferReadyEvent) {
        CloseHandle(m_bufferReadyEvent);
        m_bufferReadyEvent = 0;
    }
}

bool WinDebugInterface::runLoop()
{
    m_waitHandles[TerminateEventHandle] = CreateEvent(NULL, FALSE, FALSE, NULL);
    if (GetLastError() == ERROR_ALREADY_EXISTS)
        return false;
    m_waitHandles[DataReadyEventHandle] = CreateEvent(NULL, FALSE, FALSE, L"DBWIN_DATA_READY");
    if (!m_waitHandles[TerminateEventHandle] || !m_waitHandles[DataReadyEventHandle]
            || GetLastError() == ERROR_ALREADY_EXISTS)
        return false;
    m_bufferReadyEvent = CreateEvent(NULL, FALSE, FALSE, L"DBWIN_BUFFER_READY");
    if (!m_bufferReadyEvent
            || GetLastError() == ERROR_ALREADY_EXISTS)
        return false;
    m_sharedFile = CreateFileMapping((HANDLE)-1, NULL, PAGE_READWRITE, 0, 4096, L"DBWIN_BUFFER");
    if (!m_sharedFile || GetLastError() == ERROR_ALREADY_EXISTS)
        return false;
    m_sharedMem = MapViewOfFile(m_sharedFile, FILE_MAP_READ, 0, 0,  512);
    if (!m_sharedMem)
        return false;

    LPSTR  message = reinterpret_cast<LPSTR>(m_sharedMem) + sizeof(DWORD);
    LPDWORD processId = reinterpret_cast<LPDWORD>(m_sharedMem);

    SetEvent(m_bufferReadyEvent);

    while (true) {
        const DWORD ret = WaitForMultipleObjects(HandleCount, m_waitHandles, FALSE, INFINITE);
        if (ret == WAIT_FAILED || ret - WAIT_OBJECT_0 == TerminateEventHandle)
            break;
        if (ret - WAIT_OBJECT_0 == DataReadyEventHandle) {
            emit debugOutput(*processId, QString::fromLocal8Bit(message));
            SetEvent(m_bufferReadyEvent);
        }
    }
    return true;
}

} // namespace Internal
} // namespace ProjectExplorer

#else

namespace ProjectExplorer {
namespace Internal {

WinDebugInterface *WinDebugInterface::m_instance = 0;

WinDebugInterface *WinDebugInterface::instance() { return 0; }

WinDebugInterface::WinDebugInterface(QObject *) {}

WinDebugInterface::~WinDebugInterface() {}

void WinDebugInterface::run() {}

bool WinDebugInterface::runLoop() { return false; }

} // namespace Internal
} // namespace ProjectExplorer

#endif
