PyPySide: Fix locker handling which enables Mandelbrot

Not only the QPainter, but also the QMutexLocker
were not correctly modelled after PEP 343 in the
examples. Since that is now fixed, we consider the PyPy
project not as ready, but good enough to publish it.

It also turned out that people have the expectation
to use QSignalBlocker in the "as" form:

    with QSignalBlocker(self.double_spin_box) as blocker:
        self.double_spin_box.setValue(2.5)

https://stackoverflow.com/questions/60384734/how-to-use-qsignalblocker-in-python

But that blocker would be None.

As a side effect, QMutexLocker, QReadLocker, QWriteLocker
and QSignalBlocker were augmented with a default
__enter__ implementation that returns the locker instance.

[ChangeLog][PySide6] The Mandelbrot example needed context managers
for QPainter and QMutexLocker to work in PyPy.

Task-number: PYSIDE-535
Pick-to: 6.2
Change-Id: I2a62ca645a4fddcafbf11869f14a538141f32c39
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>

1 files changed, 7 insertions, 7 deletions

diff --git a/examples/network/blockingfortuneclient/blockingfortuneclient.py b/examples/network/blockingfortuneclient/blockingfortuneclient.py
index 50f4c1662..b997a8f7d 100644
--- a/examples/network/blockingfortuneclient/blockingfortuneclient.py
+++ b/examples/network/blockingfortuneclient/blockingfortuneclient.py
@@ -73,13 +73,13 @@ class FortuneThread(QThread):
         self.wait()
 
     def request_new_fortune(self, hostname, port):
-        locker = QMutexLocker(self.mutex)
-        self._host_name = hostname
-        self.port = port
-        if not self.isRunning():
-            self.start()
-        else:
-            self.cond.wakeOne()
+        with QMutexLocker(self.mutex):
+            self._host_name = hostname
+            self.port = port
+            if not self.isRunning():
+                self.start()
+            else:
+                self.cond.wakeOne()
 
     def run(self):
         self.mutex.lock()