QProcessPrivate: repack and reorganize the members

Reduce the number of #ifdef blocks and use quint8 for the enums that
don't need more than 8 bits anyway (none of them do). Plus move the
std::function callback to an indirect block, as most users of QProcess
won't set them and this type is 4 pointers with libstdc++ and libc++.

After this, QProcessPrivate on 64-bit Unix is 688 bytes, of which:
- 392 bytes from QIODevicePrivate
- 295 bytes of own data
- 3x56 bytes per Channel (which have 5 bytes of tail padding each)
- 1 byte of tail padding and no middle padding

Pick-to: 6.5
Change-Id: Icfe44ecf285a480fafe4fffd174d188a0821d060
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

src/corelib/io/qprocess.cpp

@@ -922,7 +922,7 @@ void QProcessPrivate::setErrorAndEmit(QProcess::ProcessError error, const QStrin
     Q_Q(QProcess);
     Q_ASSERT(error != QProcess::UnknownError);
     setError(error, description);
-    emit q->errorOccurred(processError);
+    emit q->errorOccurred(QProcess::ProcessError(processError));
 }
 
 /*!
@@ -1154,7 +1154,7 @@ void QProcessPrivate::processFinished()
     //emit q->standardOutputClosed();
     //emit q->standardErrorClosed();
 
-    emit q->finished(exitCode, exitStatus);
+    emit q->finished(exitCode, QProcess::ExitStatus(exitStatus));
 
 #if defined QPROCESS_DEBUG
     qDebug("QProcessPrivate::processFinished(): process is dead");
@@ -1239,7 +1239,7 @@ QProcess::~QProcess()
 QProcess::ProcessChannelMode QProcess::processChannelMode() const
 {
     Q_D(const QProcess);
-    return d->processChannelMode;
+    return ProcessChannelMode(d->processChannelMode);
 }
 
 /*!
@@ -1269,7 +1269,7 @@ void QProcess::setProcessChannelMode(ProcessChannelMode mode)
 QProcess::InputChannelMode QProcess::inputChannelMode() const
 {
     Q_D(const QProcess);
-    return d->inputChannelMode;
+    return InputChannelMode(d->inputChannelMode);
 }
 
 /*!
@@ -1558,7 +1558,7 @@ void QProcess::setCreateProcessArgumentsModifier(CreateProcessArgumentModifier m
 std::function<void(void)> QProcess::childProcessModifier() const
 {
     Q_D(const QProcess);
-    return d->childProcessModifier;
+    return d->unixExtras ? d->unixExtras->childProcessModifier : std::function<void(void)>();
 }
 
 /*!
@@ -1602,7 +1602,9 @@ std::function<void(void)> QProcess::childProcessModifier() const
 void QProcess::setChildProcessModifier(const std::function<void(void)> &modifier)
 {
     Q_D(QProcess);
-    d->childProcessModifier = modifier;
+    if (!d->unixExtras)
+        d->unixExtras.reset(new QProcessPrivate::UnixExtras);
+    d->unixExtras->childProcessModifier = modifier;
 }
 #endif
 
@@ -1693,7 +1695,7 @@ qint64 QProcess::bytesToWrite() const
 QProcess::ProcessError QProcess::error() const
 {
     Q_D(const QProcess);
-    return d->processError;
+    return ProcessError(d->processError);
 }
 
 /*!
@@ -1704,7 +1706,7 @@ QProcess::ProcessError QProcess::error() const
 QProcess::ProcessState QProcess::state() const
 {
     Q_D(const QProcess);
-    return d->processState;
+    return ProcessState(d->processState);
 }
 
 /*!
@@ -2373,7 +2375,7 @@ int QProcess::exitCode() const
 QProcess::ExitStatus QProcess::exitStatus() const
 {
     Q_D(const QProcess);
-    return d->exitStatus;
+    return ExitStatus(d->exitStatus);
 }
 
 /*!

src/corelib/io/qprocess_p.h

@@ -259,20 +259,6 @@ public:
     bool _q_startupNotification();
     void _q_processDied();
 
-    QProcess::ProcessChannelMode processChannelMode = QProcess::SeparateChannels;
-    QProcess::InputChannelMode inputChannelMode = QProcess::ManagedInputChannel;
-    QProcess::ProcessError processError = QProcess::UnknownError;
-    QProcess::ProcessState processState = QProcess::NotRunning;
-    QString workingDirectory;
-#ifdef Q_OS_WIN
-    Q_PROCESS_INFORMATION *pid = nullptr;
-#else
-    qint64 pid = 0;
-#endif
-
-    bool emittedReadyRead = false;
-    bool emittedBytesWritten = false;
-
     Channel stdinChannel;
     Channel stdoutChannel;
     Channel stderrChannel;
@@ -286,22 +272,33 @@ public:
 
     QString program;
     QStringList arguments;
+    QString workingDirectory;
+    QProcessEnvironment environment = QProcessEnvironment::InheritFromParent;
 #if defined(Q_OS_WIN)
     QString nativeArguments;
     QProcess::CreateProcessArgumentModifier modifyCreateProcessArgs;
-#else
-    std::function<void(void)> childProcessModifier;
-#endif
-    QProcessEnvironment environment = QProcessEnvironment::InheritFromParent;
-
-#ifdef Q_OS_UNIX
-    Q_PIPE childStartedPipe[2] = {INVALID_Q_PIPE, INVALID_Q_PIPE};
-    QSocketNotifier *stateNotifier = nullptr;
-    int forkfd = -1;
-#else
     QWinEventNotifier *processFinishedNotifier = nullptr;
+    Q_PROCESS_INFORMATION *pid = nullptr;
+#else
+    struct UnixExtras {
+        std::function<void(void)> childProcessModifier;
+    };
+    std::unique_ptr<UnixExtras> unixExtras;
+    qint64 pid = 0;
+    QSocketNotifier *stateNotifier = nullptr;
+    Q_PIPE childStartedPipe[2] = {INVALID_Q_PIPE, INVALID_Q_PIPE};
+    int forkfd = -1;
 #endif
 
+    int exitCode = 0;
+    quint8 processState = QProcess::NotRunning;
+    quint8 exitStatus = QProcess::NormalExit;
+    quint8 processError = QProcess::UnknownError;
+    quint8 processChannelMode = QProcess::SeparateChannels;
+    quint8 inputChannelMode = QProcess::ManagedInputChannel;
+    bool emittedReadyRead = false;
+    bool emittedBytesWritten = false;
+
     void start(QIODevice::OpenMode mode);
     void startProcess();
 #if defined(Q_OS_UNIX)
@@ -325,9 +322,6 @@ public:
 
     bool startDetached(qint64 *pPid);
 
-    int exitCode = 0;
-    QProcess::ExitStatus exitStatus = QProcess::NormalExit;
-
     bool waitForStarted(const QDeadlineTimer &deadline);
     bool waitForReadyRead(const QDeadlineTimer &deadline);
     bool waitForBytesWritten(const QDeadlineTimer &deadline);

src/corelib/io/qprocess_unix.cpp

@@ -544,8 +544,10 @@ void QProcessPrivate::execChild(const char *workingDir, char **argv, char **envp
         goto report_errno;
     }
 
-    if (childProcessModifier)
-        childProcessModifier();
+    if (unixExtras) {
+        if (unixExtras->childProcessModifier)
+            unixExtras->childProcessModifier();
+    }
 
     // execute the process
     if (!envp) {