Keymap: automate using OSKey for Ctrl on macos

Replace hard coded use of oskey with a function.

Add checks to avoid conflicting bindings with the OS.

release/scripts/modules/bl_keymap_utils/platform_helpers.py

@@ -0,0 +1,55 @@
+# ##### BEGIN GPL LICENSE BLOCK #####
+#
+#  This program is free software; you can redistribute it and/or
+#  modify it under the terms of the GNU General Public License
+#  as published by the Free Software Foundation; either version 2
+#  of the License, or (at your option) any later version.
+#
+#  This program is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#  GNU General Public License for more details.
+#
+#  You should have received a copy of the GNU General Public License
+#  along with this program; if not, write to the Free Software Foundation,
+#  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+#
+# ##### END GPL LICENSE BLOCK #####
+
+
+def keyconfig_data_oskey_from_ctrl(keyconfig_data_src, filter_fn=None):
+    keyconfig_data_dst = []
+    for km_name, km_parms, km_items_data_src in keyconfig_data_src:
+        km_items_data_dst = km_items_data_src.copy()
+        items_dst = []
+        km_items_data_dst["items"] = items_dst
+        for item_src in km_items_data_src["items"]:
+            item_op, item_event, item_prop = item_src
+            if "ctrl" in item_event:
+                if filter_fn is None or filter_fn(item_event):
+                    item_event = item_event.copy()
+                    item_event["oskey"] = item_event["ctrl"]
+                    del item_event["ctrl"]
+                    items_dst.append((item_op, item_event, item_prop))
+            items_dst.append(item_src)
+        keyconfig_data_dst.append((km_name, km_parms, km_items_data_dst))
+    return keyconfig_data_dst
+
+
+def keyconfig_data_oskey_from_ctrl_for_macos(keyconfig_data_src):
+    """Use for apple since Cmd is typically used in-place of Ctrl."""
+    def filter_fn(item_event):
+        if (item_event["type"] in {
+                'H',
+                'M',
+                'SPACE',
+                'W',
+        }) and (
+            item_event.get("ctrl") and
+            (not item_event.get("alt")) and
+            (not item_event.get("shift"))
+        ):
+            return False
+        return True
+
+    return keyconfig_data_oskey_from_ctrl(keyconfig_data_src, filter_fn)