override SFNTReader __deepcopy__ for 'file' isn't copyable; use it in varLib

Lib/fontTools/ttLib/sfnt.py

@@ -123,6 +123,31 @@ class SFNTReader(object):
 	def close(self):
 		self.file.close()
 
+	def __deepcopy__(self, memo):
+		"""Overrides the default deepcopy of SFNTReader object, to make it work
+		in the case when TTFont is loaded with lazy=True, and thus reader holds a
+		reference to a file object which is not pickleable.
+		We work around it by manually copying the data into a in-memory stream.
+		"""
+		from copy import deepcopy
+
+		cls = self.__class__
+		obj = cls.__new__(cls)
+		for k, v in self.__dict__.items():
+			if k == "file":
+				f = self.file
+				start = f.tell()
+				f.seek(0)
+				buf = BytesIO(f.read())
+				f.seek(start)
+				buf.seek(start)
+				if hasattr(f, "name"):
+					buf.name = f.name
+				obj.file = buf
+			else:
+				obj.__dict__[k] = deepcopy(v, memo)
+		return obj
+
 
 # default compression level for WOFF 1.0 tables and metadata
 ZLIB_COMPRESSION_LEVEL = 6

Lib/fontTools/ttLib/ttFont.py

@@ -693,19 +693,6 @@ class TTFont(object):
 		"""
 		return self["cmap"].getBestCmap(cmapPreferences=cmapPreferences)
 
-	def copy(self):
-		"""Return a new TTFont instance containing the same data.
-
-		>>> f1 = TTFont()
-		>>> f2 = f1.copy()
-		>>> f2 is not f1
-		True
-		"""
-		buf = BytesIO()
-		self.save(buf)
-		buf.seek(0)
-		return TTFont(buf)
-
 
 class _TTGlyphSet(object):
 

Lib/fontTools/varLib/__init__.py

@@ -40,6 +40,7 @@ from fontTools.designspaceLib import DesignSpaceDocument, AxisDescriptor
 from collections import OrderedDict, namedtuple
 import os.path
 import logging
+from copy import deepcopy
 from pprint import pformat
 
 log = logging.getLogger("fontTools.varLib")
@@ -764,7 +765,7 @@ def build(designspace, master_finder=lambda s:s, exclude=[], optimize=True):
 			master_ttfs.append(None)  # in-memory fonts have no path
 
 	# Copy the base master to work from it
-	vf = master_fonts[ds.base_idx].copy()
+	vf = deepcopy(master_fonts[ds.base_idx])
 
 	# TODO append masters as named-instances as well; needs .designspace change.
 	fvar = _add_fvar(vf, ds.axes, ds.instances)

Lib/fontTools/varLib/interpolate_layout.py

@@ -8,6 +8,7 @@ from fontTools.varLib import models, VarLibError, load_designspace, load_masters
 from fontTools.varLib.merger import InstancerMerger
 import os.path
 import logging
+from copy import deepcopy
 from pprint import pformat
 
 log = logging.getLogger("fontTools.varLib.interpolate_layout")
@@ -37,7 +38,7 @@ def interpolate_layout(designspace, loc, master_finder=lambda s:s, mapped=False)
 
 	log.info("Loading master fonts")
 	master_fonts = load_masters(designspace, master_finder)
-	font = master_fonts[ds.base_idx].copy()
+	font = deepcopy(master_fonts[ds.base_idx])
 
 	log.info("Location: %s", pformat(loc))
 	if not mapped: