Opportunistically use iondrive if available

Lib/fontmake/font_project.py

@@ -27,6 +27,7 @@
 import ufo2ft
 import ufo2ft.errors
 import ufoLib2
+import ufoLib2.objects
 from fontTools import designspaceLib
 from fontTools.misc.loggingTools import Timer, configLogger
 from fontTools.misc.plistlib import load as readPlist
@@ -118,6 +119,12 @@ def __init__(self, timing=False, verbose="INFO", validate_ufo=False):
 
     def open_ufo(self, path):
         try:
+            try:
+                import iondrive
+
+                return iondrive.load(ufoLib2.objects, path)
+            except ImportError:
+                pass
             return ufoLib2.Font.open(path, validate=self.validate_ufo)
         except Exception as e:
             raise FontmakeError("Reading UFO source failed", path) from e

setup.py

@@ -34,6 +34,7 @@
         # "lxml>=4.2.4",
     ],
     "mutatormath": ["MutatorMath>=2.1.2"],
+    "iondrive": ["iondrive>=1.0"],
 }
 # use a special 'all' key as shorthand to includes all the extra dependencies
 extras_require["all"] = sum(extras_require.values(), [])