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Do not try to handle OOM exceptions in logging

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We duplicate quite some code here in an attempt to still print
messages, even in OOM situations. However, we've in general given up
on handling OOM exceptions gracefully in Qt: On modern systems
you hardly reach the point of not being able to allocate (smaller)
chunks in the first place, since the system will usually overcommit,
or bring the system to halt by heavy paging.

In 7cafb62538 we removed already similar logic in QDebug
class.

Change-Id: I4f84641c41c5e230a60dc0b7a5b0a13dec20f90f
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
This commit is contained in:
Kai Koehne 2014-06-04 12:10:24 +02:00 committed by The Qt Project
parent 9e01483cdf
commit 7cbd9cffd3
1 changed files with 3 additions and 77 deletions
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80
src/corelib/global/qlogging.cpp
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@ -171,89 +171,15 @@ static inline void convert_to_wchar_t_elided(wchar_t *d, size_t space, const cha
}
#endif
#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) Q_DECL_NOEXCEPT
{
char emergency_buf[256] = { '\0' };
emergency_buf[sizeof emergency_buf - 1] = '\0';
#if defined(Q_OS_WIN) && defined(QT_BUILD_CORE_LIB) && (defined(Q_OS_WINCE) || defined(Q_OS_WINRT)) \
|| defined(Q_CC_MSVC) && defined(QT_DEBUG) && defined(_DEBUG) && defined(_CRT_ERROR)
wchar_t emergency_bufL[sizeof emergency_buf];
#endif
if (msg)
qvsnprintf(emergency_buf, sizeof emergency_buf - 1, msg, ap);
#if defined(Q_OS_WIN) && defined(QT_BUILD_CORE_LIB)
# if defined(Q_OS_WINCE) || defined(Q_OS_WINRT)
convert_to_wchar_t_elided(emergency_bufL, sizeof emergency_buf, emergency_buf);
OutputDebugStringW(emergency_bufL);
# else
if (qWinLogToStderr()) {
fprintf(stderr, "%s\n", emergency_buf);
fflush(stderr);
} else {
OutputDebugStringA(emergency_buf);
}
# endif
#else
fprintf(stderr, "%s\n", emergency_buf);
fflush(stderr);
#endif
if (isFatal(msgType)) {
#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);
# ifndef Q_OS_WINCE // otherwise already converted to wchar_t above
convert_to_wchar_t_elided(emergency_bufL, sizeof emergency_buf, emergency_buf);
# endif
int ret = _CrtDbgReportW(_CRT_ERROR, _CRT_WIDE(__FILE__), __LINE__,
_CRT_WIDE(QT_VERSION_STR),
emergency_bufL);
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, QString &buf)
{
#if !defined(QT_NO_EXCEPTIONS)
if (std::uncaught_exception()) {
qEmergencyOut(msgType, msg, ap);
return;
}
#endif
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
}
}
if (msg)
buf = QString().vsprintf(msg, ap);
qt_message_print(msgType, context, buf);
}