path: root/src/corelib/global/qlogging.cpp

/****************************************************************************
**
** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** GNU Lesser General Public License Usage
** This file may be used under the terms of the GNU Lesser General Public
** License version 2.1 as published by the Free Software Foundation and
** appearing in the file LICENSE.LGPL included in the packaging of this
** file. Please review the following information to ensure the GNU Lesser
** General Public License version 2.1 requirements will be met:
** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights. These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU General
** Public License version 3.0 as published by the Free Software Foundation
** and appearing in the file LICENSE.GPL included in the packaging of this
** file. Please review the following information to ensure the GNU General
** Public License version 3.0 requirements will be met:
** http://www.gnu.org/copyleft/gpl.html.
**
** Other Usage
** Alternatively, this file may be used in accordance with the terms and
** conditions contained in a signed written agreement between you and Nokia.
**
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**
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**
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "qlogging.h"
#include "qlist.h"
#include "qbytearray.h"
#include "qstring.h"
#include "qvarlengtharray.h"
#include "qdebug.h"
#ifndef QT_BOOTSTRAPPED
#include "qcoreapplication.h"
#include "qthread.h"
#endif
#ifdef Q_OS_WIN
#include <qt_windows.h>
#endif

#include <stdio.h>

QT_BEGIN_NAMESPACE

/*!
    \class QMessageLogContext
    \relates <QtGlobal>
    \brief The QMessageLogContext class provides additional information about a log message.
    \since 5.0

    The class provides information about the source code location a qDebug(), qWarning(),
    qCritical() or qFatal() message was generated.

    \sa QMessageLogger, QtMessageHandler, qInstallMessageHandler()
*/

/*!
    \class QMessageLogger
    \relates <QtGlobal>
    \brief The QMessageLogger class generates log messages.
    \since 5.0

    QMessageLogger is used to generate messages for the Qt logging framework. Usually one uses
    it through qDebug(), qWarning(), qCritical, or qFatal() functions,
    which are actually macros that expand to QMessageLogger(__FILE__, __LINE__, Q_FUNC_INFO).debug()
    et al.

    One example of direct use is to forward errors that stem from a scripting language, e.g. QML:

    \snippet doc/src/snippets/code/qlogging/qloggingsnippet.cpp 1

    \sa QMessageLogContext, qDebug(), qWarning(), qCritical(), qFatal()
*/

#if !defined(QT_NO_EXCEPTIONS)
/*!
    \internal
    Uses a local buffer to output the message. Not locale safe + cuts off
    everything after character 255, but will work in out of memory situations.
    Stop the execution afterwards.
*/
static void qEmergencyOut(QtMsgType msgType, const char *msg, va_list ap)
{
    char emergency_buf[256] = { '\0' };
    emergency_buf[255] = '\0';
    if (msg)
        qvsnprintf(emergency_buf, 255, msg, ap);

#if defined(Q_OS_WIN) && defined(QT_BUILD_CORE_LIB)
    OutputDebugStringA(emergency_buf);
#else
    fprintf(stderr, "%s", emergency_buf);
    fflush(stderr);
#endif

    if (msgType == QtFatalMsg
            || (msgType == QtWarningMsg
                && (!qgetenv("QT_FATAL_WARNINGS").isNull())) ) {
#if defined(Q_CC_MSVC) && defined(QT_DEBUG) && defined(_DEBUG) && defined(_CRT_ERROR)
        // get the current report mode
        int reportMode = _CrtSetReportMode(_CRT_ERROR, _CRTDBG_MODE_WNDW);
        _CrtSetReportMode(_CRT_ERROR, reportMode);
        int ret = _CrtDbgReport(_CRT_ERROR, __FILE__, __LINE__, QT_VERSION_STR,
                                msg);
        if (ret == 1)
            _CrtDbgBreak();
#endif

#if (defined(Q_OS_UNIX) || defined(Q_CC_MINGW))
        abort(); // trap; generates core dump
#else
        exit(1); // goodbye cruel world
#endif
    }
}
#endif

/*!
    \internal
*/
static void qt_message(QtMsgType msgType, const QMessageLogContext &context, const char *msg,
                       va_list ap)
{
#if !defined(QT_NO_EXCEPTIONS)
    if (std::uncaught_exception()) {
        qEmergencyOut(msgType, msg, ap);
        return;
    }
#endif
    QString buf;
    if (msg) {
        QT_TRY {
            buf = QString().vsprintf(msg, ap);
        } QT_CATCH(const std::bad_alloc &) {
#if !defined(QT_NO_EXCEPTIONS)
            qEmergencyOut(msgType, msg, ap);
            // don't rethrow - we use qWarning and friends in destructors.
            return;
#endif
        }
    }
    qt_message_output(msgType, context, buf);
}

#undef qDebug

void QMessageLogger::debug(const char *msg, ...)
{
    va_list ap;
    va_start(ap, msg); // use variable arg list
    qt_message(QtDebugMsg, context, msg, ap);
    va_end(ap);
}

#ifndef QT_NO_DEBUG_STREAM

QDebug QMessageLogger::debug()
{
    QDebug dbg = QDebug(QtDebugMsg);
    QMessageLogContext &ctxt = dbg.stream->context;
    ctxt.copy(context);
    return dbg;
}

QNoDebug QMessageLogger::noDebug()
{
    return QNoDebug();
}

#endif

#undef qWarning
void QMessageLogger::warning(const char *msg, ...)
{
    va_list ap;
    va_start(ap, msg); // use variable arg list
    qt_message(QtWarningMsg, context, msg, ap);
    va_end(ap);
}

#ifndef QT_NO_DEBUG_STREAM
QDebug QMessageLogger::warning()
{
    QDebug dbg = QDebug(QtWarningMsg);
    QMessageLogContext &ctxt = dbg.stream->context;
    ctxt.copy(context);
    return dbg;
}
#endif

#undef qCritical

void QMessageLogger::critical(const char *msg, ...)
{
    va_list ap;
    va_start(ap, msg); // use variable arg list
    qt_message(QtCriticalMsg, context, msg, ap);
    va_end(ap);
}

#ifndef QT_NO_DEBUG_STREAM
QDebug QMessageLogger::critical()
{
    QDebug dbg = QDebug(QtCriticalMsg);
    QMessageLogContext &ctxt = dbg.stream->context;
    ctxt.copy(context);
    return dbg;
}
#endif

#undef qFatal

void QMessageLogger::fatal(const char *msg, ...)
{
    va_list ap;
    va_start(ap, msg); // use variable arg list
    qt_message(QtFatalMsg, context, msg, ap);
    va_end(ap);
}

/*!
    \internal
*/
Q_AUTOTEST_EXPORT QByteArray qCleanupFuncinfo(QByteArray info)
{
    // Strip the function info down to the base function name
    // note that this throws away the template definitions,
    // the parameter types (overloads) and any const/volatile qualifiers.

    if (info.isEmpty())
        return info;

    int pos;

    // skip trailing [with XXX] for templates (gcc)
    pos = info.size() - 1;
    if (info.endsWith(']')) {
        while (--pos) {
            if (info.at(pos) == '[')
                info.truncate(pos);
        }
    }

    // operator names with '(', ')', '<', '>' in it
    static const char operator_call[] = "operator()";
    static const char operator_lessThan[] = "operator<";
    static const char operator_greaterThan[] = "operator>";
    static const char operator_lessThanEqual[] = "operator<=";
    static const char operator_greaterThanEqual[] = "operator>=";

    // canonize operator names
    info.replace("operator ", "operator");

    // remove argument list
    forever {
        int parencount = 0;
        pos = info.lastIndexOf(')');
        if (pos == -1) {
            // Don't know how to parse this function name
            return info;
        }

        // find the beginning of the argument list
        --pos;
        ++parencount;
        while (pos && parencount) {
            if (info.at(pos) == ')')
                ++parencount;
            else if (info.at(pos) == '(')
                --parencount;
            --pos;
        }
        if (parencount != 0)
            return info;

        info.truncate(++pos);

        if (info.at(pos - 1) == ')') {
            if (info.indexOf(operator_call) == pos - (int)strlen(operator_call))
                break;

            // this function returns a pointer to a function
            // and we matched the arguments of the return type's parameter list
            // try again
            info.remove(0, info.indexOf('('));
            info.chop(1);
            continue;
        } else {
            break;
        }
    }

    // find the beginning of the function name
    int parencount = 0;
    int templatecount = 0;
    --pos;

    // make sure special characters in operator names are kept
    if (pos > -1) {
        switch (info.at(pos)) {
        case ')':
            if (info.indexOf(operator_call) == pos - (int)strlen(operator_call) + 1)
                pos -= 2;
            break;
        case '<':
            if (info.indexOf(operator_lessThan) == pos - (int)strlen(operator_lessThan) + 1)
                --pos;
            break;
        case '>':
            if (info.indexOf(operator_greaterThan) == pos - (int)strlen(operator_greaterThan) + 1)
                --pos;
            break;
        case '=': {
            int operatorLength = (int)strlen(operator_lessThanEqual);
            if (info.indexOf(operator_lessThanEqual) == pos - operatorLength + 1)
                pos -= 2;
            else if (info.indexOf(operator_greaterThanEqual) == pos - operatorLength + 1)
                pos -= 2;
            break;
        }
        default:
            break;
        }
    }

    while (pos > -1) {
        if (parencount < 0 || templatecount < 0)
            return info;

        char c = info.at(pos);
        if (c == ')')
            ++parencount;
        else if (c == '(')
            --parencount;
        else if (c == '>')
            ++templatecount;
        else if (c == '<')
            --templatecount;
        else if (c == ' ' && templatecount == 0 && parencount == 0)
            break;

        --pos;
    }
    info = info.mid(pos + 1);

    // remove trailing '*', '&' that are part of the return argument
    while ((info.at(0) == '*')
           || (info.at(0) == '&'))
        info = info.mid(1);

    // we have the full function name now.
    // clean up the templates
    while ((pos = info.lastIndexOf('>')) != -1) {
        if (!info.contains('<'))
            break;

        // find the matching close
        int end = pos;
        templatecount = 1;
        --pos;
        while (pos && templatecount) {
            register char c = info.at(pos);
            if (c == '>')
                ++templatecount;
            else if (c == '<')
                --templatecount;
            --pos;
        }
        ++pos;
        info.remove(pos, end - pos + 1);
    }

    return info;
}

// tokens as recognized in QT_MESSAGE_PATTERN
static const char categoryTokenC[] = "%{category}";
static const char typeTokenC[] = "%{type}";
static const char messageTokenC[] = "%{message}";
static const char fileTokenC[] = "%{file}";
static const char lineTokenC[] = "%{line}";
static const char functionTokenC[] = "%{function}";
static const char pidTokenC[] = "%{pid}";
static const char appnameTokenC[] = "%{appname}";
static const char threadidTokenC[] = "%{threadid}";
static const char emptyTokenC[] = "";

struct QMessagePattern {
    QMessagePattern();
    ~QMessagePattern();

    // 0 terminated arrays of literal tokens / literal or placeholder tokens
    const char **literals;
    const char **tokens;
};

QMessagePattern::QMessagePattern()
{
    QString pattern = QString::fromLocal8Bit(qgetenv("QT_MESSAGE_PATTERN"));
    if (pattern.isEmpty()) {
        pattern = QLatin1String("%{message}");
    }

    // scanner
    QList<QString> lexemes;
    QString lexeme;
    bool inPlaceholder = false;
    for (int i = 0; i < pattern.size(); ++i) {
        const QChar c = pattern.at(i);
        if ((c == QLatin1Char('%'))
                && !inPlaceholder) {
            if ((i + 1 < pattern.size())
                    && pattern.at(i + 1) == QLatin1Char('{')) {
                // beginning of placeholder
                if (!lexeme.isEmpty()) {
                    lexemes.append(lexeme);
                    lexeme.clear();
                }
                inPlaceholder = true;
            }
        }

        lexeme.append(c);

        if ((c == QLatin1Char('}') && inPlaceholder)) {
            // end of placeholder
            lexemes.append(lexeme);
            lexeme.clear();
            inPlaceholder = false;
        }
    }
    if (!lexeme.isEmpty())
        lexemes.append(lexeme);

    // tokenizer
    QVarLengthArray<const char*> literalsVar;
    tokens = new const char*[lexemes.size() + 1];
    tokens[lexemes.size()] = 0;

    for (int i = 0; i < lexemes.size(); ++i) {
        const QString lexeme = lexemes.at(i);
        if (lexeme.startsWith(QLatin1String("%{"))
                && lexeme.endsWith(QLatin1Char('}'))) {
            // placeholder
            if (lexeme == QLatin1String(typeTokenC)) {
                tokens[i] = typeTokenC;
            } else if (lexeme == QLatin1String(categoryTokenC))
                tokens[i] = categoryTokenC;
            else if (lexeme == QLatin1String(messageTokenC))
                tokens[i] = messageTokenC;
            else if (lexeme == QLatin1String(fileTokenC))
                tokens[i] = fileTokenC;
            else if (lexeme == QLatin1String(lineTokenC))
                tokens[i] = lineTokenC;
            else if (lexeme == QLatin1String(functionTokenC))
                tokens[i] = functionTokenC;
            else if (lexeme == QLatin1String(pidTokenC))
                tokens[i] = pidTokenC;
            else if (lexeme == QLatin1String(appnameTokenC))
                tokens[i] = appnameTokenC;
            else if (lexeme == QLatin1String(threadidTokenC))
                tokens[i] = threadidTokenC;
            else {
                fprintf(stderr, "%s\n",
                        QString::fromLatin1("QT_MESSAGE_PATTERN: Unknown placeholder %1\n"
                                            ).arg(lexeme).toLatin1().constData());
                fflush(stderr);
                tokens[i] = emptyTokenC;
            }
        } else {
            char *literal = new char[lexeme.size() + 1];
            strncpy(literal, lexeme.toLatin1().constData(), lexeme.size());
            literal[lexeme.size()] = '\0';
            literalsVar.append(literal);
            tokens[i] = literal;
        }
    }
    literals = new const char*[literalsVar.size() + 1];
    literals[literalsVar.size()] = 0;
    memcpy(literals, literalsVar.constData(), literalsVar.size() * sizeof(const char*));
}

QMessagePattern::~QMessagePattern()
{
    for (int i = 0; literals[i] != 0; ++i)
        delete [] literals[i];
    delete [] literals;
    literals = 0;
    delete [] tokens;
    tokens = 0;
}

Q_GLOBAL_STATIC(QMessagePattern, qMessagePattern)

/*!
    \internal
*/
Q_CORE_EXPORT QString qMessageFormatString(QtMsgType type, const QMessageLogContext &context,
                                              const QString &str)
{
    QString message;

    QMessagePattern *pattern = qMessagePattern();
    if (!pattern) {
        // after destruction of static QMessagePattern instance
        message.append(str);
        message.append(QLatin1Char('\n'));
        return message;
    }

    // we do not convert file, function, line literals to local encoding due to overhead
    for (int i = 0; pattern->tokens[i] != 0; ++i) {
        const char *token = pattern->tokens[i];
        if (token == messageTokenC) {
            message.append(str);
        } else if (token == categoryTokenC) {
            message.append(QLatin1String(context.category));
        } else if (token == typeTokenC) {
            switch (type) {
            case QtDebugMsg:   message.append(QLatin1String("debug")); break;
            case QtWarningMsg: message.append(QLatin1String("warning")); break;
            case QtCriticalMsg:message.append(QLatin1String("critical")); break;
            case QtFatalMsg:   message.append(QLatin1String("fatal")); break;
            }
        } else if (token == fileTokenC) {
            if (context.file)
                message.append(QLatin1String(context.file));
            else
                message.append(QLatin1String("unknown"));
        } else if (token == lineTokenC) {
            message.append(QString::number(context.line));
        } else if (token == functionTokenC) {
            if (context.function)
                message.append(QString::fromLatin1(qCleanupFuncinfo(context.function)));
            else
                message.append(QLatin1String("unknown"));
#ifndef QT_BOOTSTRAPPED
        } else if (token == pidTokenC) {
            message.append(QString::number(QCoreApplication::applicationPid()));
        } else if (token == appnameTokenC) {
            message.append(QCoreApplication::applicationName());
        } else if (token == threadidTokenC) {
            message.append(QLatin1String("0x"));
            message.append(QString::number(qlonglong(QThread::currentThread()->currentThread()), 16));
#endif
        } else {
            message.append(QLatin1String(token));
        }
    }
    message.append(QLatin1Char('\n'));
    return message;
}

static QtMsgHandler msgHandler = 0;                // pointer to debug handler (without context)
static QtMessageHandler messageHandler = 0;         // pointer to debug handler (with context)
static QMessageHandler messageHandler2 = 0;       // TODO: Remove before Qt5.0 beta

/*!
    \internal
*/
static void qDefaultMessageHandler(QtMsgType type, const QMessageLogContext &context,
                                   const QString &buf)
{
    QString logMessage = qMessageFormatString(type, context, buf);
#if defined(Q_OS_WINCE)
    OutputDebugString(reinterpret_cast<const wchar_t *> (logMessage.utf16()));
#else
    fprintf(stderr, "%s", logMessage.toLocal8Bit().constData());
    fflush(stderr);
#endif
}

/*!
    \internal
*/
static void qDefaultMessageHandler2(QtMsgType type, const QMessageLogContext &context,
                                   const char *buf)
{
    qDefaultMessageHandler(type, context, QString::fromLocal8Bit(buf));
}

/*!
    \internal
*/
static void qDefaultMsgHandler(QtMsgType type, const char *buf)
{
    QMessageLogContext emptyContext;
    qDefaultMessageHandler(type, emptyContext, QLatin1String(buf));
}

/*!
    \internal
*/
void qt_message_output(QtMsgType msgType, const QMessageLogContext &context, const QString &message)
{
    if (!msgHandler)
        msgHandler = qDefaultMsgHandler;
    if (!messageHandler)
        messageHandler = qDefaultMessageHandler;
    if (!messageHandler2)
        messageHandler2 = qDefaultMessageHandler2;

    if (messageHandler == qDefaultMessageHandler
            && messageHandler2 != qDefaultMessageHandler2)
        (*messageHandler2)(msgType, context, message.toLocal8Bit().constData());

    // prefer new message handler over the old one
    if (msgHandler == qDefaultMsgHandler
            || messageHandler != qDefaultMessageHandler) {
        (*messageHandler)(msgType, context, message);
    } else {
        (*msgHandler)(msgType, message.toLocal8Bit().constData());
    }

    if (msgType == QtFatalMsg
            || (msgType == QtWarningMsg
                && (!qgetenv("QT_FATAL_WARNINGS").isNull())) ) {

#if defined(Q_CC_MSVC) && defined(QT_DEBUG) && defined(_DEBUG) && defined(_CRT_ERROR)
        // get the current report mode
        int reportMode = _CrtSetReportMode(_CRT_ERROR, _CRTDBG_MODE_WNDW);
        _CrtSetReportMode(_CRT_ERROR, reportMode);

        int ret = _CrtDbgReportW(_CRT_ERROR, reinterpret_cast<const wchar_t *> (
                                     QString::fromLatin1(context.file).utf16()),
                                 context.line, _CRT_WIDE(QT_VERSION_STR),
                                 reinterpret_cast<const wchar_t *> (
                                     message.utf16()));
        if (ret == 0  && reportMode & _CRTDBG_MODE_WNDW)
            return; // ignore
        else if (ret == 1)
            _CrtDbgBreak();
#endif

#if (defined(Q_OS_UNIX) || defined(Q_CC_MINGW))
        abort(); // trap; generates core dump
#else
        exit(1); // goodbye cruel world
#endif
    }
}

void qErrnoWarning(const char *msg, ...)
{
    // qt_error_string() will allocate anyway, so we don't have
    // to be careful here (like we do in plain qWarning())
    QString buf;
    va_list ap;
    va_start(ap, msg);
    if (msg)
        buf.vsprintf(msg, ap);
    va_end(ap);

    buf += QLatin1String(" (") + qt_error_string(-1) + QLatin1Char(')');
    QMessageLogContext context;
    qt_message_output(QtCriticalMsg, context, buf);
}

void qErrnoWarning(int code, const char *msg, ...)
{
    // qt_error_string() will allocate anyway, so we don't have
    // to be careful here (like we do in plain qWarning())
    QString buf;
    va_list ap;
    va_start(ap, msg);
    if (msg)
        buf.vsprintf(msg, ap);
    va_end(ap);

    buf += QLatin1String(" (") + qt_error_string(code) + QLatin1Char(')');
    QMessageLogContext context;
    qt_message_output(QtCriticalMsg, context, buf);
}

#if defined(Q_OS_WIN) && defined(QT_BUILD_CORE_LIB)
extern bool usingWinMain;
extern Q_CORE_EXPORT void qWinMsgHandler(QtMsgType t, const char *str);
extern Q_CORE_EXPORT void qWinMessageHandler(QtMsgType t, const QMessageLogContext &context,
                                             const QString &str);

void qWinMessageHandler2(QtMsgType t, const QMessageLogContext &context,
                         const char *str)
{
    qWinMessageHandler(t, context, QString::fromLocal8Bit(str));
}
#endif

QtMessageHandler qInstallMessageHandler(QtMessageHandler h)
{
    if (!messageHandler)
        messageHandler = qDefaultMessageHandler;
    QtMessageHandler old = messageHandler;
    messageHandler = h;
#if defined(Q_OS_WIN) && defined(QT_BUILD_CORE_LIB)
    if (!messageHandler && usingWinMain)
        messageHandler = qWinMessageHandler;
#endif
    return old;
}

QMessageHandler qInstallMessageHandler(QMessageHandler h)
{
    if (!messageHandler2)
        messageHandler2 = qDefaultMessageHandler2;
    QMessageHandler old = messageHandler2;
    messageHandler2 = h;
#if defined(Q_OS_WIN) && defined(QT_BUILD_CORE_LIB)
    if (!messageHandler2 && usingWinMain)
        messageHandler2 = qWinMessageHandler2;
#endif
    return old;
}

QtMsgHandler qInstallMsgHandler(QtMsgHandler h)
{
    //if handler is 0, set it to the
    //default message handler
    if (!msgHandler)
        msgHandler = qDefaultMsgHandler;
    QtMsgHandler old = msgHandler;
    msgHandler = h;
#if defined(Q_OS_WIN) && defined(QT_BUILD_CORE_LIB)
    if (!msgHandler && usingWinMain)
        msgHandler = qWinMsgHandler;
#endif
    return old;
}

void QMessageLogContext::copy(const QMessageLogContext &logContext)
{
    this->category = logContext.category;
    this->file = logContext.file;
    this->line = logContext.line;
    this->function = logContext.function;
}
QT_END_NAMESPACE