label listed updates in text output

bin/simple-apt-update

@@ -112,7 +112,7 @@ class UpdateWindow(Gtk.ApplicationWindow):
     def insert(self, text, iter):
         self.buffer.insert(iter, text + "\n")
 
-    def run_thread(self, args, env):
+    def run_thread(self, args, env, prefix=None):
         if self.thread is None:
             do_run = True
         elif not self.thread.is_alive():
@@ -123,7 +123,7 @@ class UpdateWindow(Gtk.ApplicationWindow):
         if do_run:
             self.thread = threading.Thread(
                 target=self.run,
-                args=(args, env,))
+                args=(args, env, prefix,))
 
             self.thread.start()
 
@@ -137,6 +137,7 @@ class UpdateWindow(Gtk.ApplicationWindow):
         ignore_stderr=False,
         output_msg=None,
         empty_msg=None,
+        prefix=None,
         env={},
         clear=True
     ):
@@ -154,9 +155,15 @@ class UpdateWindow(Gtk.ApplicationWindow):
             "INFO",
             "Running command \"%s\" ..." % " ".join(args))
 
-        GLib.timeout_add(250, self.run_thread, args, env)
+        GLib.timeout_add(
+            250,
+            self.run_thread,
+            args,
+            env,
+            prefix
+        )
 
-    def run(self, args, env={}):
+    def run(self, args, env={}, prefix=None):
         p = subprocess.Popen(
             args,
             stdout=subprocess.PIPE,
@@ -175,7 +182,10 @@ class UpdateWindow(Gtk.ApplicationWindow):
 
                 if data:
                     if key.fileobj is p.stdout:
-                        self.stdout_queue.put(data)
+                        if prefix is None:
+                            self.stdout_queue.put(data)
+                        else:
+                            self.stdout_queue.put(prefix + " " + data)
                     else:
                         self.stderr_queue.put(data)
 
@@ -222,7 +232,8 @@ class UpdateWindow(Gtk.ApplicationWindow):
             args,
             ignore_stderr=True,
             clear=clear,
-            output_msg="Found the following package upgrades:",
+            prefix="UPDATE",
+            output_msg="Done listing available upgrades.",
             empty_msg="No package upgrades found."
         )
 
@@ -238,29 +249,39 @@ class UpdateWindow(Gtk.ApplicationWindow):
     def on_quit(self, *args):
         self.application.quit()
 
+    def process_exit(self, exit_code, empty_msg=None, output_msg=None):
+        self.thread.join()
+
+        if exit_code != 0:
+            self.append_mesg(
+                "ERROR",
+                "Command exited with code %d" % exit_code
+            )
+        elif self.stdout == '' and self.empty_msg is not None:
+            self.append_mesg("INFO", self.empty_msg)
+        elif self.stdout != '' and self.output_msg is not None:
+            self.append_mesg("INFO", self.output_msg)
+
+        self.unlock()
+
     def update_buffer(self):
         try:
             text = self.stdout_queue.get(block=False)
-            match = re.fullmatch(r'EXIT (\d+)', text)
+            match = re.fullmatch(r'(EXIT|UPDATE) (.*)', text)
 
             if match is None:
                 self.stdout += text
                 self.append_mesg("STDOUT", text)
+            elif match.group(1) == 'EXIT':
+                exit_code = int(match.group(2))
+                self.process_exit(exit_code)
+            elif match.group(1) == 'UPDATE':
+                text = match.group(2)
+                self.stdout += text
+                self.append_mesg("UPDATE", text)
             else:
-                exit_code = int(match.group(1))
+                self.stdout += text
-                self.thread.join()
+                self.append_mesg("UPDATE", text)
-
-                if exit_code != 0:
-                    self.append_mesg(
-                        "ERROR",
-                        "Command exited with code %d" % exit_code
-                    )
-                elif self.stdout == '' and self.empty_msg is not None:
-                    self.append_mesg("INFO", self.empty_msg)
-                elif self.stdout != '' and self.output_msg is not None:
-                    self.append_mesg("INFO", self.output_msg)
-
-                self.unlock()
 
         except queue.Empty:
             pass