/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
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**
** 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
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** 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
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#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;
}

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

WinDebugInterface::~WinDebugInterface()
{
    if (m_waitHandles[TerminateEventHandle]) {
        SetEvent(m_waitHandles[TerminateEventHandle]);
        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
