examples: Improvements to the asyncio examples

- The asyncio AsyncHelper enters a quasi idle loop of switching between
  the asyncio event loop and the Qt event loop, where the asyncio event
  loop never receives new work at some point (besides yielding to Qt)
  and wastes memory and CPU cycles. Remedy this by signaling to
  AsyncHelper when asyncio's work is done.
- Don't pass signals as parameters.
- Fix comments in the asyncio examples that mentioned Trio.
- Renamed the requirements files as only the Trio examples need them.
- Remove unused imports.

Task-number: PYSIDE-2169
Change-Id: Ia7197ea3446dd6ae514089b0dd260214c458db6a
Reviewed-by: Christian Tismer <tismer@stackless.com>
(cherry picked from commit e49516c724a11ac084372b5f0d7d62a35af363cc)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

1 files changed, 7 insertions, 7 deletions

diff --git a/examples/async/eratosthenes/eratosthenes_trio.py b/examples/async/eratosthenes/eratosthenes_trio.py
index 5fb2a35be..862a4fddd 100644
--- a/examples/async/eratosthenes/eratosthenes_trio.py
+++ b/examples/async/eratosthenes/eratosthenes_trio.py
@@ -61,7 +61,7 @@ class MainWindow(QMainWindow):
         widget.setPalette(palette)
 
 
-class Eratosthenes():
+class Eratosthenes(QObject):
 
     """ This Sieve of Eratosthenes runs on a configurable tick (default
         0.1 seconds). At each tick, a new subroutine will be created
@@ -69,6 +69,7 @@ class Eratosthenes():
         these subroutines also operates on the same tick. """
 
     def __init__(self, num, window, tick=0.1):
+        super().__init__()
         self.num = num
         self.sieve = [True] * self.num
         self.base = 0
@@ -119,8 +120,6 @@ class Eratosthenes():
 
 class AsyncHelper(QObject):
 
-    trigger_signal = Signal()
-
     class ReenterQtObject(QObject):
         """ This is a QObject to which an event will be posted, allowing
             Trio to resume when the event is handled. event.fn() is the
@@ -138,13 +137,14 @@ class AsyncHelper(QObject):
             super().__init__(QEvent.Type(QEvent.User + 1))
             self.fn = fn
 
-    def __init__(self, entry=None):
+    def __init__(self, worker, entry):
         super().__init__()
         self.reenter_qt = self.ReenterQtObject()
         self.entry = entry
 
-    def set_entry(self, entry):
-        self.entry = entry
+        self.worker = worker
+        if hasattr(self.worker, "start_signal") and isinstance(self.worker.start_signal, Signal):
+            self.worker.start_signal.connect(self.launch_guest_run)
 
     @Slot()
     def launch_guest_run(self):
@@ -183,7 +183,7 @@ if __name__ == "__main__":
     app = QApplication(sys.argv)
     main_window = MainWindow(rows, cols)
     eratosthenes = Eratosthenes(num, main_window)
-    async_helper = AsyncHelper(entry=eratosthenes.start)
+    async_helper = AsyncHelper(eratosthenes, eratosthenes.start)
 
     # This establishes the entry point for the Trio guest run. It varies
     # depending on how and when its event loop is to be triggered, e.g.,