Add async buffered pubsub, websocket updates endpoint and initial fast hashing of objects

yacv_server/tessellate.py

@@ -1,5 +1,8 @@
 import concurrent
 import copyreg
+import hashlib
+import io
+import re
 from concurrent.futures import ProcessPoolExecutor, Executor
 from dataclasses import dataclass
 from typing import Tuple, Callable, Generator
@@ -9,7 +12,9 @@ import numpy as np
 from OCP.BRep import BRep_Tool
 from OCP.BRepAdaptor import BRepAdaptor_Curve
 from OCP.GCPnts import GCPnts_TangentialDeflection
+from OCP.TopExp import TopExp
 from OCP.TopLoc import TopLoc_Location
+from OCP.TopTools import TopTools_IndexedMapOfShape
 from OCP.TopoDS import TopoDS_Face, TopoDS_Edge, TopoDS_Shape, TopoDS_Vertex
 from build123d import Face, Vector, Shape, Vertex
 from partcad.wrappers import cq_serialize
@@ -188,3 +193,21 @@ def _tessellate_vertex(ocp_vertex: TopoDS_Vertex) -> GLTF2:
         pbrMetallicRoughness=PbrMetallicRoughness(baseColorFactor=[1.0, 0.5, 0.5, 1.0]),
         alphaCutoff=None)
     return create_gltf(vertices, indices, tex_coord, mode, material)
+
+
+def _hashcode(obj: TopoDS_Shape) -> str:
+    """Utility to compute the hash code of a shape recursively without the need to tessellate it"""
+    # NOTE: obj.HashCode(MAX_HASH_CODE) is not stable across different runs of the same program
+    # This is best-effort and not guaranteed to be unique
+    data = io.BytesIO()
+    map_of_shapes = TopTools_IndexedMapOfShape()
+    TopExp.MapShapes_s(obj, map_of_shapes)
+    for i in range(1, map_of_shapes.Extent() + 1):
+        sub_shape = map_of_shapes.FindKey(i)
+        sub_data = io.BytesIO()
+        TopoDS_Shape.DumpJson(sub_shape, sub_data)
+        val = sub_data.getvalue()
+        val = re.sub(b'"this": "[^"]*"', b'', val)  # Remove memory address
+        data.write(val)
+    to_hash = data.getvalue()
+    return hashlib.md5(to_hash, usedforsecurity=False).hexdigest()