ufo2ft rust precompilation patch

precompilation.patch

diff --git a/Lib/ufo2ft/__init__.py b/Lib/ufo2ft/__init__.py
index 4295caa..a98528a 100644
--- a/Lib/ufo2ft/__init__.py
+++ b/Lib/ufo2ft/__init__.py
@@ -1,12 +1,15 @@
 import logging
 import os
 from enum import IntEnum
+import tempfile
 
 from fontTools import varLib
 from fontTools.designspaceLib import DesignSpaceDocument
 from fontTools.designspaceLib.split import splitInterpolable, splitVariableFonts
 from fontTools.otlLib.optimize.gpos import GPOS_COMPACT_MODE_ENV_KEY
 
+from glyphcompiler import compile as precompile_glyphs
+
 from ufo2ft.constants import SPARSE_OTF_MASTER_TABLES, SPARSE_TTF_MASTER_TABLES
 from ufo2ft.errors import InvalidDesignSpaceData
 from ufo2ft.featureCompiler import (
@@ -14,9 +17,14 @@ from ufo2ft.featureCompiler import (
     FeatureCompiler,
     MtiFeatureCompiler,
 )
-from ufo2ft.outlineCompiler import OutlineOTFCompiler, OutlineTTFCompiler
+from ufo2ft.outlineCompiler import (
+    OutlineOTFCompiler,
+    OutlineTTFCompiler,
+    PrecompiledTTFCompiler,
+)
 from ufo2ft.postProcessor import PostProcessor
 from ufo2ft.preProcessor import (
+    BasePreProcessor,
     OTFPreProcessor,
     TTFInterpolatablePreProcessor,
     TTFPreProcessor,
@@ -26,6 +34,7 @@ from ufo2ft.util import (
     ensure_all_sources_have_names,
     init_kwargs,
     prune_unknown_kwargs,
+    _GlyphSet,
 )
 
 try:
@@ -260,6 +269,7 @@ compileInterpolatableTTFs_args = {
         flattenComponents=False,
         layerNames=None,
         colrLayerReuse=False,
+        precompiledGlyphs=None,
     ),
 }
 
@@ -294,15 +304,36 @@ def compileInterpolatableTTFs(ufos, **kwargs):
         kwargs["layerNames"] = [None] * len(ufos)
     assert len(ufos) == len(kwargs["layerNames"])
 
-    glyphSets = call_preprocessor(ufos, **kwargs)
+    if kwargs["precompiledGlyphs"]:
+        kwargs["outlineCompilerClass"] = PrecompiledTTFCompiler
+        kwargs["preProcessorClass"] = BasePreProcessor
+        precompiledGlyphs = kwargs["precompiledGlyphs"]
+        glyphSets = [
+            _GlyphSet.from_layer(
+                ufo,
+                layerName,
+                copy=not kwargs["inplace"],
+                skipExportGlyphs=kwargs["skipExportGlyphs"],
+            )
+            for ufo, layerName in zip(ufos, kwargs["layerNames"])
+        ]
+    else:
+        precompiledGlyphs = None
+        glyphSets = call_preprocessor(ufos, **kwargs)
 
-    for ufo, glyphSet, layerName in zip(ufos, glyphSets, kwargs["layerNames"]):
+    for ix, (ufo, glyphSet, layerName) in enumerate(
+        zip(ufos, glyphSets, kwargs["layerNames"])
+    ):
         fontName = _LazyFontName(ufo)
         if layerName is not None:
             logger.info("Building OpenType tables for %s-%s", fontName, layerName)
         else:
             logger.info("Building OpenType tables for %s", fontName)
 
+        if precompiledGlyphs:
+            kwargs["precompiledGlyphs"] = {
+                k: v[ix] for k, v in precompiledGlyphs.items()
+            }
         ttf = call_outline_compiler(
             ufo,
             glyphSet,
@@ -375,6 +406,16 @@ def compileInterpolatableTTFsFromDS(designSpaceDoc, **kwargs):
     if kwargs["notdefGlyph"] is None:
         kwargs["notdefGlyph"] = _getDefaultNotdefGlyph(designSpaceDoc)
 
+    if True:  # Basically if the filter set is "predictable"
+        # Oh, at this point, I don't actually know where it lives. It's just a text file, let's save it.
+        root = os.path.commonpath([s.path for s in designSpaceDoc.sources])
+        tmpname = root + "/tmp.designspace"
+        glyphset = (
+            designSpaceDoc.findDefault().font.keys()
+        )  # Forget skipExportGlyphs for now
+        designSpaceDoc.write(tmpname)
+        kwargs["precompiledGlyphs"] = precompile_glyphs(tmpname, list(glyphset))
+
     ttfs = compileInterpolatableTTFs(ufos, **kwargs)
 
     if kwargs["inplace"]:
diff --git a/Lib/ufo2ft/outlineCompiler.py b/Lib/ufo2ft/outlineCompiler.py
index 424f706..943255b 100644
--- a/Lib/ufo2ft/outlineCompiler.py
+++ b/Lib/ufo2ft/outlineCompiler.py
@@ -1508,6 +1508,28 @@ class OutlineTTFCompiler(BaseOutlineCompiler):
                     break
 
 
+class PrecompiledTTFCompiler(OutlineTTFCompiler):
+    def __init__(
+        self,
+        font,
+        glyphSet=None,
+        glyphOrder=None,
+        tables=None,
+        notdefGlyph=None,
+        colrLayerReuse=True,
+        precompiledGlyphs=None,
+    ):
+        super().__init__(
+            font,
+            glyphSet=glyphSet,
+            glyphOrder=glyphOrder,
+            tables=tables,
+            notdefGlyph=notdefGlyph,
+            colrLayerReuse=colrLayerReuse,
+        )
+        self._compiledGlyphs = precompiledGlyphs
+
+
 class StubGlyph:
 
     """