Generate layouts arrays used in settings

`gen_layouts.py` lists the layouts in `res/xml` and generate the
`pref_layout_values` and `pref_layout_entries` arrays into
`res/values/layouts.xml`.

These arrays are hard to maintain as the order has to match, which is
fragile.

This relies on every layouts having a `name` attribute.

1 files changed, 64 insertions, 0 deletions

diff --git a/gen_layouts.py b/gen_layouts.py
new file mode 100644
index 0000000..2b86883
--- /dev/null
+++ b/gen_layouts.py
@@ -0,0 +1,64 @@
+#!/usr/bin/env python
+
+# Generates the list of layouts in res/values/layouts.xml from the layout files
+# in res/xml. Every layouts must have a 'name' attribute to be listed.
+
+import itertools as it
+import sys, os, glob
+import xml.etree.ElementTree as XML
+
+# Layouts first in the list (these are the programming layouts). Other layouts
+# are sorted alphabetically.
+FIRST_LAYOUTS = [ "latn_qwerty_us", "latn_colemak", "latn_dvorak" ]
+
+# Read a layout from a file. Returns [None] if [fname] is not a layout.
+def read_layout(fname):
+    root = XML.parse(fname).getroot()
+    if root.tag != "keyboard":
+        return None
+    return { "name": root.get("name") }
+
+# Yields the id (based on the file name) and the display name for every layouts
+def read_layouts(files):
+    for layout_file in files:
+        layout_id, _ = os.path.splitext(os.path.basename(layout_file))
+        layout = read_layout(layout_file)
+        if layout == None:
+            print("Not a layout file: %s" % layout_file)
+        elif layout["name"] == None:
+            print("Layout doesn't have a name: %s" % layout_id)
+        else:
+            yield (layout_id, layout["name"])
+
+# Sort layouts alphabetically, except for layouts in FIRST_LAYOUTS, which are
+# placed at the top.
+# Returns a list. 'layouts' can be an iterator.
+def sort_layouts(layouts):
+    layouts = dict(layouts)
+    head = [ (lid, layouts.pop(lid)) for lid in FIRST_LAYOUTS ]
+    return head + sorted(layouts.items())
+
+# Write the XML arrays used in the preferences.
+def generate_arrays(out, layouts):
+    def add_items(parent, strings):
+        for s in strings:
+            item = XML.Element("item")
+            item.text = s
+            parent.append(item)
+    none_item = [ ("none", "None") ]
+    custom_item = [ ("custom", "@string/pref_layout_e_custom") ]
+    lids, names = zip(*(none_item + layouts + custom_item)) # unzip
+    values = XML.Element("string-array", name="pref_layout_values")
+    add_items(values, lids)
+    entries = XML.Element("string-array", name="pref_layout_entries")
+    add_items(entries, names)
+    root = XML.Element("resources")
+    root.append(XML.Comment(text="DO NOT EDIT. This file is generated, see gen_layouts.py."))
+    root.append(values)
+    root.append(entries)
+    XML.indent(root)
+    XML.ElementTree(element=root).write(out, encoding="unicode", xml_declaration=True)
+
+layouts = sort_layouts(read_layouts(glob.glob("res/xml/*.xml")))
+with open("res/values/layouts.xml", "w") as out:
+    generate_arrays(out, layouts)