get-state: Move code into __main__ functions

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2448>

tools/get-state.py

@@ -13,41 +13,6 @@ class Source(enum.Enum):
     FILE = 2
 
 
-parser = argparse.ArgumentParser(description='Get display state')
-parser.add_argument('file', metavar='FILE', type=str, nargs='?',
-                    help='Read the output from gdbus call instead of calling D-Bus')
-parser.add_argument('--short', action='store_true')
-
-args = parser.parse_args()
-
-if args.file:
-  source = Source.FILE
-  path = args.file
-else:
-  source = Source.DBUS
-
-short = args.short
-
-type_signature = '(ua((ssss)a(siiddada{sv})a{sv})a(iiduba(ssss)a{sv})a{sv})'
-variant_type = GLib.VariantType.new(type_signature)
-
-if source == Source.DBUS:
-    command = 'gdbus call -e '\
-        '-d org.gnome.Mutter.DisplayConfig '\
-        '-o /org/gnome/Mutter/DisplayConfig '\
-        '-m org.gnome.Mutter.DisplayConfig.GetCurrentState'
-    result = subprocess.run(command,
-                            shell=True, check=True, capture_output=True, text=True)
-    data = result.stdout
-else:
-    if path == '-':
-        data = sys.stdin.read()
-    else:
-        with open(path) as file:
-            data = file.read()
-
-variant = GLib.variant_parse(variant_type, data)
-
 def transform_to_string(transform):
     match transform:
         case 0: return 'normal'
@@ -97,6 +62,35 @@ def print_properties(level, lines, properties):
         print_data(level + 1, is_last, lines,
                 f'{property} ⇒ {properties[property]}')
 
+def print_current_state(args):
+    if args.file:
+        source = Source.FILE
+        path = args.file
+    else:
+        source = Source.DBUS
+
+    short = args.short
+
+    type_signature = '(ua((ssss)a(siiddada{sv})a{sv})a(iiduba(ssss)a{sv})a{sv})'
+    variant_type = GLib.VariantType.new(type_signature)
+
+    if source == Source.DBUS:
+        command = 'gdbus call -e '\
+            '-d org.gnome.Mutter.DisplayConfig '\
+            '-o /org/gnome/Mutter/DisplayConfig '\
+            '-m org.gnome.Mutter.DisplayConfig.GetCurrentState'
+        result = subprocess.run(command,
+                                shell=True, check=True, capture_output=True, text=True)
+        data = result.stdout
+    else:
+        if path == '-':
+            data = sys.stdin.read()
+        else:
+            with open(path) as file:
+                data = file.read()
+
+    variant = GLib.variant_parse(variant_type, data)
+
     print('Serial: {}'.format(variant[0]))
     print()
     print('Monitors:')
@@ -108,7 +102,8 @@ for monitor in monitors:
         modes = monitor[1]
         properties = monitor[2]
         print_data(0, is_last, lines, 'Monitor {}'.format(spec[0]))
-    print_data(1, False, lines, f'EDID: vendor: {spec[1]}, product: {spec[2]}, serial: {spec[3]}')
+        print_data(
+            1, False, lines, f'EDID: vendor: {spec[1]}, product: {spec[2]}, serial: {spec[3]}')
 
         mode_count = len(modes)
         if short:
@@ -164,3 +159,14 @@ for logical_monitor in logical_monitors:
     properties = variant[3]
     print()
     print_properties(-1, lines, properties)
+
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser(description='Get display state')
+    parser.add_argument('file', metavar='FILE', type=str, nargs='?',
+                        help='Read the output from gdbus call instead of calling D-Bus')
+    parser.add_argument('--short', action='store_true')
+
+    args = parser.parse_args()
+
+    print_current_state(args)