Terminate subprocesses when the application is quit

For #3

src/pydiode/gui/common.py

@@ -77,30 +77,30 @@ def stuck_running(returncodes):
         return False
 
 
-def check_subprocesses(widget, cancelled, *args):
+def check_subprocesses(widget, cancelled, processes):
     """
     Check whether all the subprocesses have exited. If so, display their error
     messages and clean up after them.
 
     :param widget: Used to schedule another check
     :param cancelled: Boolean variable indicating cancellation request
-    :param args: An array of tuples, each containing a subprocess's name and
-                 its popen object.
+    :param processes: An array of tuples, each containing a subprocess's name
+                      and its popen object.
     """
     # If requested, cancel subprocesses
     if cancelled.get():
         # Signal each process to exit
-        for name, popen in args:
+        for name, popen in processes:
             popen.terminate()
         # Mark this cancellation request as handled
         cancelled.set(False)
         # At the next check, hopefully the processes will have exited
         widget.after(
-            SLEEP, lambda: check_subprocesses(widget, cancelled, *args)
+            SLEEP, lambda: check_subprocesses(widget, cancelled, processes)
         )
     else:
         # Get returncodes for exited processes, None for running processes
-        returncodes = [popen.poll() for name, popen in args]
+        returncodes = [popen.poll() for name, popen in processes]
         # Are any of the subprocesses still running?
         still_running = any(code is None for code in returncodes)
 
@@ -109,10 +109,10 @@ def check_subprocesses(widget, cancelled, *args):
             # Request termination of the processes
             cancelled.set(True)
             widget.after(
-                SLEEP, lambda: check_subprocesses(widget, cancelled, *args)
+                SLEEP, lambda: check_subprocesses(widget, cancelled, processes)
             )
             # Describe the issue
-            process_names = [name for name, popen in args]
+            process_names = [name for name, popen in processes]
             error_msgs = get_premature_errors(
                 list(zip(process_names, returncodes))
             )
@@ -121,15 +121,18 @@ def check_subprocesses(widget, cancelled, *args):
         # If subprocesses are still running, keep waiting for them
         elif still_running:
             widget.after(
-                SLEEP, lambda: check_subprocesses(widget, cancelled, *args)
+                SLEEP, lambda: check_subprocesses(widget, cancelled, processes)
             )
         # Otherwise, all subprocesses have exited
         else:
             # If any subprocesses exited irregularly, describe the issue
-            error_msgs = get_process_errors(args)
+            error_msgs = get_process_errors(processes)
             if error_msgs:
                 showerror(title="Error", message=error_msgs)
             # Clean up
-            for name, popen in args:
+            for name, popen in processes:
                 popen.stdout.close()
                 popen.stderr.close()
+            # The array of subprocesses should be cleared, so it doesn't grow
+            # each time more subprocesses are started
+            processes.clear()

src/pydiode/gui/main.py

@@ -3,13 +3,17 @@
 import sys
 from tkinter import BooleanVar, IntVar, Listbox, StringVar, Tk, ttk
 
-
-from pydiode.gui.receive import receive_files, set_target_directory
+from pydiode.gui.receive import (
+    receive_files,
+    set_target_directory,
+    RECEIVE_PROCESSES,
+)
 from pydiode.gui.send import (
     add_source_files,
     remove_source_files,
     send_files,
     update_tx_btn,
+    SEND_PROCESSES,
 )
 import pydiode.pydiode
 import pydiode.tar
@@ -166,9 +170,17 @@ def gui_main():
     port.set(config["pydiode"].get("port", "1234"))
     # TODO Add options for maximum bitrate and redundancy
 
+    # Override the default behavior of the Quit menu, so it doesn't cause the
+    # application to exit immediately
+    root.createcommand("tk::mac::Quit", root.quit)
+
     # Start handling user input
     root.mainloop()
 
+    # Cancel send and receive subprocesses
+    for name, popen in SEND_PROCESSES + RECEIVE_PROCESSES:
+        popen.terminate()
+
     # Save settings
     config["pydiode"] = {
         "tab": active_tab.get(),

src/pydiode/gui/receive.py

@@ -4,6 +4,9 @@
 
 from pydiode.gui.common import check_subprocesses, SLEEP
 
+# An array of tuples, each containing a subprocess's name and its popen object
+RECEIVE_PROCESSES = []
+
 
 def set_target_directory(target):
     """
@@ -45,11 +48,10 @@ def receive_files(
             stdout=subprocess.PIPE,
             stderr=subprocess.PIPE,
         )
+        RECEIVE_PROCESSES.extend([("pydiode", pydiode), ("tar", tar)])
         root.after(
             SLEEP,
-            lambda: check_subprocesses(
-                root, cancelled, ("pydiode", pydiode), ("tar", tar)
-            ),
+            lambda: check_subprocesses(root, cancelled, RECEIVE_PROCESSES),
         )
 
         def animate():

src/pydiode/gui/send.py

@@ -16,6 +16,8 @@
 OVERHEAD = 1.085
 # Increment progress bars every 25 milliseconds, for smooth animation.
 INCREMENT_INTERVAL = 25
+# An array of tuples, each containing a subprocess's name and its popen object
+SEND_PROCESSES = []
 
 
 def add_source_files(sources_var, sources_list):
@@ -132,14 +134,10 @@ def send_files(
             stdout=subprocess.PIPE,
             stderr=subprocess.PIPE,
         )
+        SEND_PROCESSES.extend([("tar", tar), ("pydiode", pydiode)])
         root.after(
             SLEEP,
-            lambda: check_subprocesses(
-                root,
-                cancelled,
-                ("tar", tar),
-                ("pydiode", pydiode),
-            ),
+            lambda: check_subprocesses(root, cancelled, SEND_PROCESSES),
         )
 
         increment_size = get_increment_size(sources_list, progress_bar)