Introduce QSocketNotifier::activate(QSocketDescriptor, QSN::Type)

The pre-existing overload passes an int, but this can mean the
descriptor gets truncated in compilations where the descriptor
is 64-bit.

The old overload with int is visible when querying the metaobject system
so string-based connects still work as before, and connecting to it will
produce a deprecation warning in the output.
At the same time the PMF-based connect will, on recompile, pick the
QSocketDescriptor overload. As an added improvement it also comes with
the notification type, removing the need for separate slots where the
code would be mostly shared anyway.

The QSocketDescriptor type can be implicitly converted to and from
qintptr to ensure existing code still compiles. It can also be
constructed from Qt::HANDLE on Windows.

In this same patch I also update the existing string-based connects in
this module, which then includes updating the parameters for some slots
as well.

[ChangeLog][QtCore][QSocketNotifier] Added
QSocketNotifier::activated(QSocketDescriptor, QSocketNotifier::Type).
This replaces the activated(int) signal which in 64-bit environments
could truncate the socket descriptor. If you use "activated" with the
string-based connect() then you need to update the parameter type of the
signal and slot if it had one. If you use it with the pointer to member
function based connect() then all you need to do is update your slot's
parameter type if it has one. If you need to compile your source code
with multiple versions of Qt then connect() to this function using
pointer to member function and update the slot's parameter type if
needed.

Task-number: QTBUG-70441
Change-Id: Ic43d6bc4c5bcb4040867b2ffad8d36fb01eed8af
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>

3 files changed, 6 insertions, 6 deletions

diff --git a/src/corelib/io/qfilesystemwatcher_inotify.cpp b/src/corelib/io/qfilesystemwatcher_inotify.cpp
index 888af998a5..94d9d06bcb 100644
--- a/src/corelib/io/qfilesystemwatcher_inotify.cpp
+++ b/src/corelib/io/qfilesystemwatcher_inotify.cpp
@@ -253,7 +253,7 @@ QInotifyFileSystemWatcherEngine::QInotifyFileSystemWatcherEngine(int fd, QObject
       notifier(fd, QSocketNotifier::Read, this)
 {
     fcntl(inotifyFd, F_SETFD, FD_CLOEXEC);
-    connect(&notifier, SIGNAL(activated(int)), SLOT(readFromInotify()));
+    connect(&notifier, SIGNAL(activated(QSocketDescriptor)), SLOT(readFromInotify()));
 }
 
 QInotifyFileSystemWatcherEngine::~QInotifyFileSystemWatcherEngine()
diff --git a/src/corelib/io/qfilesystemwatcher_kqueue.cpp b/src/corelib/io/qfilesystemwatcher_kqueue.cpp
index c2028e3641..06383a103a 100644
--- a/src/corelib/io/qfilesystemwatcher_kqueue.cpp
+++ b/src/corelib/io/qfilesystemwatcher_kqueue.cpp
@@ -77,7 +77,7 @@ QKqueueFileSystemWatcherEngine::QKqueueFileSystemWatcherEngine(int kqfd, QObject
       kqfd(kqfd),
       notifier(kqfd, QSocketNotifier::Read, this)
 {
-    connect(&notifier, SIGNAL(activated(int)), SLOT(readFromKqueue()));
+    connect(&notifier, SIGNAL(activated(QSocketDescriptor)), SLOT(readFromKqueue()));
 
     fcntl(kqfd, F_SETFD, FD_CLOEXEC);
 }
diff --git a/src/corelib/io/qprocess_unix.cpp b/src/corelib/io/qprocess_unix.cpp
index 930007ff04..e8efe6481f 100644
--- a/src/corelib/io/qprocess_unix.cpp
+++ b/src/corelib/io/qprocess_unix.cpp
@@ -251,7 +251,7 @@ bool QProcessPrivate::openChannel(Channel &channel)
                 channel.notifier = new QSocketNotifier(channel.pipe[1],
                                                        QSocketNotifier::Write, q);
                 channel.notifier->setEnabled(false);
-                QObject::connect(channel.notifier, SIGNAL(activated(int)),
+                QObject::connect(channel.notifier, SIGNAL(activated(QSocketDescriptor)),
                                  q, SLOT(_q_canWrite()));
             } else {
                 channel.notifier = new QSocketNotifier(channel.pipe[0],
@@ -261,7 +261,7 @@ bool QProcessPrivate::openChannel(Channel &channel)
                     receiver = SLOT(_q_canReadStandardOutput());
                 else
                     receiver = SLOT(_q_canReadStandardError());
-                QObject::connect(channel.notifier, SIGNAL(activated(int)),
+                QObject::connect(channel.notifier, SIGNAL(activated(QSocketDescriptor)),
                                  q, receiver);
             }
         }
@@ -380,7 +380,7 @@ void QProcessPrivate::startProcess()
     if (threadData.loadRelaxed()->hasEventDispatcher()) {
         startupSocketNotifier = new QSocketNotifier(childStartedPipe[0],
                                                     QSocketNotifier::Read, q);
-        QObject::connect(startupSocketNotifier, SIGNAL(activated(int)),
+        QObject::connect(startupSocketNotifier, SIGNAL(activated(QSocketDescriptor)),
                          q, SLOT(_q_startupNotification()));
     }
 
@@ -531,7 +531,7 @@ void QProcessPrivate::startProcess()
 
     if (threadData.loadRelaxed()->eventDispatcher.loadAcquire()) {
         deathNotifier = new QSocketNotifier(forkfd, QSocketNotifier::Read, q);
-        QObject::connect(deathNotifier, SIGNAL(activated(int)),
+        QObject::connect(deathNotifier, SIGNAL(activated(QSocketDescriptor)),
                          q, SLOT(_q_processDied()));
     }
 }