add ok_for_raid property, enable/disable create raid button as appropriate

subiquity/models/filesystem.py

@@ -199,6 +199,11 @@ class _Formattable(ABC):
         assert action in self.supported_actions
         return getattr(self, "_can_" + action.name)
 
+    @property
+    @abstractmethod
+    def ok_for_raid(self):
+        pass
+
 
 # Nothing is put in the first and last megabytes of the disk to allow
 # space for the GPT data.
@@ -360,6 +365,8 @@ class Disk(_Device):
         not self.grub_device and self._fs is None
         and self._constructed_device is None)
 
+    ok_for_raid = _can_FORMAT
+
 
 @attr.s(cmp=False)
 class Partition(_Formattable):
@@ -405,6 +412,16 @@ class Partition(_Formattable):
     _can_DELETE = property(
         lambda self: self.flag not in ('boot', 'bios_grub'))
 
+    @property
+    def ok_for_raid(self):
+        if self.flag:
+            return False
+        if self._fs is not None:
+            return False
+        if self._constructed_device is not None:
+            return False
+        return True
+
 
 @attr.s(cmp=False)
 class Raid(_Device):
@@ -445,6 +462,14 @@ class Raid(_Device):
     def path(self):
         return "/dev/{}".format(self.name)
 
+    @property
+    def ok_for_raid(self):
+        if self._fs is not None:
+            return False
+        if self._constructed_device is not None:
+            return False
+        return True
+
 
 @attr.s(cmp=False)
 class Filesystem:

subiquity/ui/views/filesystem/filesystem.py

@@ -176,7 +176,6 @@ class MountList(WidgetWrap):
         self._no_mounts_content = Color.info_minor(
             Text(_("No disks or partitions mounted.")))
         super().__init__(self.table)
-        self.refresh_model_inputs()
 
     def _mount_action(self, sender, action, mount):
         log.debug('_mount_action %s %s', action, mount)
@@ -276,9 +275,6 @@ class DeviceList(WidgetWrap):
             text = _("No used devices")
         self._no_devices_content = Color.info_minor(Text(text))
         super().__init__(self.table)
-        self.refresh_model_inputs()
-        # I don't really know why this is required:
-        self.table._select_first_selectable()
 
     _disk_INFO = _stretchy_shower(DiskInfoStretchy)
     _disk_PARTITION = _stretchy_shower(PartitionStretchy)
@@ -462,9 +458,9 @@ class FilesystemView(BaseView):
         self.avail_list = DeviceList(self, True)
         self.used_list = DeviceList(self, False)
         self.avail_list.table.bind(self.used_list.table)
-        self._create_raid_btn = menu_btn(
+        self._create_raid_btn = Toggleable(menu_btn(
             label=_("Create software RAID (md)"),
-            on_press=self.create_raid)
+            on_press=self.create_raid))
 
         bp = button_pile([self._create_raid_btn])
         bp.align = 'left'
@@ -494,12 +490,12 @@ class FilesystemView(BaseView):
             focus_buttons=self.model.can_install())
         frame.width = ('relative', 95)
         super().__init__(frame)
+        self.refresh_model_inputs()
         log.debug('FileSystemView init complete()')
 
     def _build_buttons(self):
         log.debug('FileSystemView: building buttons')
         self.done = Toggleable(done_btn(_("Done"), on_press=self.done))
-        self.done.enabled = self.model.can_install()
 
         return [
             self.done,
@@ -508,14 +504,19 @@ class FilesystemView(BaseView):
             ]
 
     def refresh_model_inputs(self):
+        raid_devices = set()
+        for d in self.model.all_devices():
+            if d.ok_for_raid:
+                raid_devices.add(d)
+            for p in d.partitions():
+                if p.ok_for_raid:
+                    raid_devices.add(p)
+            self._create_raid_btn.enabled = len(raid_devices) > 1
         self.mount_list.refresh_model_inputs()
         self.avail_list.refresh_model_inputs()
         self.used_list.refresh_model_inputs()
-        # If refreshing the view has left the focus widget with no
-        # selectable widgets, simulate a tab to move to the next
-        # selectable widget.
-        while not self.lb.base_widget.focus.selectable():
-            self.lb.base_widget.keypress((10, 10), 'tab')
+        # This is an awful hack, actual thinking required:
+        self.lb.base_widget._select_first_selectable()
         self.done.enabled = self.model.can_install()
 
     def create_raid(self, button=None):

subiquity/ui/views/filesystem/raid.py

@@ -54,10 +54,8 @@ from subiquitycore.ui.utils import (
 from .partition import FSTypeField
 from subiquity.ui.mount import MountField
 from subiquity.models.filesystem import (
-    DeviceAction,
     get_raid_size,
     humanize_size,
-    Partition,
     raidlevels,
     raidlevels_by_value,
     )
@@ -346,15 +344,7 @@ class RaidStretchy(Stretchy):
                 return False
             if dev in cur_devices:
                 return True
-            if dev.fs():
-                return False
-            if dev in cur_devices:
-                return True
-            if dev.constructed_device() is not None:
-                return False
-            if isinstance(dev, Partition):
-                return not dev.flag
-            return dev.action_possible(DeviceAction.FORMAT)
+            return dev.ok_for_raid
 
         for dev in self.parent.model.all_devices():
             if device_ok(dev):