Fix some narrowing conversion warnings

ioctl call for FIONREAD takes an int arg, it won't work correctly
otherwise. Cast the return of the read() call to int, because it won't
read more than buffSize (which is an int).

Change-Id: I130202a732684257bbb0e79c9358b60a61010c46
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/global/qlogging.cpp

@@ -1632,7 +1632,7 @@ QString qFormatLogMessage(QtMsgType type, const QMessageLogContext &context, con
             } else if (timeFormat == "boot"_L1) {
                 // just print the milliseconds since the elapsed timer reference
                 // like the Linux kernel does
-                uint ms = QDeadlineTimer::current().deadline();
+                qint64 ms = QDeadlineTimer::current().deadline();
                 message.append(QString::asprintf("%6d.%03d", uint(ms / 1000), uint(ms % 1000)));
 #if QT_CONFIG(datestring)
             } else if (timeFormat.isEmpty()) {

src/corelib/io/qfilesystemwatcher_inotify.cpp

@@ -334,7 +334,7 @@ void QInotifyFileSystemWatcherEngine::readFromInotify()
         return;
 
     QVarLengthArray<char, 4096> buffer(buffSize);
-    buffSize = read(inotifyFd, buffer.data(), buffSize);
+    buffSize = int(read(inotifyFd, buffer.data(), buffSize));
     char *at = buffer.data();
     char * const end = at + buffSize;
 

src/corelib/io/qiodevice.cpp

@@ -1500,7 +1500,7 @@ qint64 QIODevice::readLineData(char *data, qint64 maxSize)
     Q_D(QIODevice);
     qint64 readSoFar = 0;
     char c;
-    int lastReadReturn = 0;
+    qint64 lastReadReturn = 0;
     d->baseReadLineDataCalled = true;
 
     while (readSoFar < maxSize && (lastReadReturn = read(&c, 1)) == 1) {

src/corelib/io/qipaddress.cpp

@@ -61,7 +61,7 @@ static bool parseIp4Internal(IPv4Address &address, const char *ptr, bool acceptL
             return false;
 
         auto [ll, used] = qstrntoull(ptr, stop - ptr, 0);
-        quint32 x = ll;
+        const quint32 x = quint32(ll);
         if (used <= 0 || ll != x)
             return false;
 

src/corelib/io/qlockfile_unix.cpp

@@ -170,7 +170,7 @@ bool QLockFilePrivate::removeStaleLock()
 
 bool QLockFilePrivate::isProcessRunning(qint64 pid, const QString &appname)
 {
-    if (::kill(pid, 0) == -1 && errno == ESRCH)
+    if (::kill(pid_t(pid), 0) == -1 && errno == ESRCH)
         return false; // PID doesn't exist anymore
 
     const QString processName = processNameByPid(pid);

src/corelib/io/qprocess_unix.cpp

@@ -95,8 +95,8 @@ struct AutoPipe
 
 struct ChildError
 {
-    qint64 code;
-    char function[8];
+    int code;
+    char function[12];
 };
 
 // Used for argv and envp arguments to execve()
@@ -568,7 +568,7 @@ bool QProcessPrivate::processStarted(QString *errorMessage)
     Q_Q(QProcess);
 
     ChildError buf;
-    int ret = qt_safe_read(childStartedPipe[0], &buf, sizeof(buf));
+    ssize_t ret = qt_safe_read(childStartedPipe[0], &buf, sizeof(buf));
 
     if (stateNotifier) {
         stateNotifier->setEnabled(false);

src/corelib/serialization/qxmlutils.cpp

@@ -48,7 +48,7 @@ bool QXmlUtils::rangeContains(RangeIter begin, RangeIter end, const QChar c)
         return cp >= begin->min;
 
     while (begin != end) {
-        int delta = (end - begin) / 2;
+        qptrdiff delta = (end - begin) / 2;
         RangeIter mid = begin + delta;
 
         if (mid->min > cp)

src/corelib/text/qstring.cpp

@@ -981,7 +981,7 @@ Q_CORE_EXPORT void qt_from_latin1(char16_t *dst, const char *str, size_t size) n
         return;
     } else {
         size = size % 4;
-        return UnrollTailLoop<3>::exec(qsizetype(size), [=](int i) { dst[i] = (uchar)str[i]; });
+        return UnrollTailLoop<3>::exec(qsizetype(size), [=](qsizetype i) { dst[i] = uchar(str[i]); });
     }
 #  endif
 #endif

src/corelib/text/qstringmatcher.cpp

@@ -13,7 +13,7 @@ static void bm_init_skiptable(QStringView needle, uchar *skiptable, Qt::CaseSens
     const char16_t *uc = needle.utf16();
     const qsizetype len =
             cs == Qt::CaseSensitive ? needle.size() : qMin(needle.size(), FoldBufferCapacity);
-    qsizetype l = qMin(len, qsizetype(255));
+    int l = qMin(int(len), 255);
     memset(skiptable, l, 256 * sizeof(uchar));
     uc += len - l;
     if (cs == Qt::CaseSensitive) {

src/corelib/time/qgregoriancalendar.cpp

@@ -93,7 +93,7 @@ bool QGregorianCalendar::validParts(int year, int month, int day)
 
 int QGregorianCalendar::weekDayOfJulian(qint64 jd)
 {
-    return qMod<7>(jd) + 1;
+    return int(qMod<7>(jd) + 1);
 }
 
 bool QGregorianCalendar::dateToJulianDay(int year, int month, int day, qint64 *jd) const

src/testlib/qbenchmarkperfevents.cpp

@@ -108,7 +108,8 @@ static QList<PerfEvent> defaultCounters()
 static int perf_event_open(perf_event_attr *attr, pid_t pid, int cpu, int group_fd, unsigned long flags)
 {
 #ifdef SYS_perf_event_open
-    return syscall(SYS_perf_event_open, attr, pid, cpu, group_fd, flags);
+    // syscall() returns long, but perf_event_open() is used to get a file descriptor
+    return int(syscall(SYS_perf_event_open, attr, pid, cpu, group_fd, flags));
 #else
     Q_UNUSED(attr);
     Q_UNUSED(pid);