Add Support for Geometry Node Cache (#92890)

Add support for geometry node simulation cache files.

This also adds support for dealing with dynamic arrays in Blender's
DNA, because `modifier.bakes` is a pointer to such an array.

Co-authored-by: Sybren A. Stüvel <sybren@blender.org>
Reviewed-on: https://projects.blender.org/blender/blender-asset-tracer/pulls/92890

blender_asset_tracer/trace/modifier_walkers.py

@@ -27,6 +27,7 @@ import logging
 import typing
 
 from blender_asset_tracer import blendfile, bpathlib, cdefs
+from blender_asset_tracer.blendfile import iterators
 from . import result
 
 log = logging.getLogger(__name__)
@@ -337,7 +338,7 @@ def modifier_dynamic_paint(
 
     surfaces = canvas_settings.get_pointer((b"surfaces", b"first"))
 
-    for surf_idx, surface in enumerate(blendfile.iterators.listbase(surfaces)):
+    for surf_idx, surface in enumerate(iterators.listbase(surfaces)):
         surface_block_name = block_name + b".canvas_settings.surfaces[%d]" % (surf_idx)
         point_cache = surface.get_pointer(b"pointcache")
         if point_cache is None:
@@ -351,3 +352,62 @@ def modifier_dynamic_paint(
         yield from _walk_point_cache(
             ctx, surface_block_name, modifier.bfile, point_cache, cdefs.PTCACHE_EXT
         )
+
+
+@mod_handler(cdefs.eModifierType_Nodes)
+def modifier_nodes(
+    ctx: ModifierContext, modifier: blendfile.BlendFileBlock, block_name: bytes
+) -> typing.Iterator[result.BlockUsage]:
+    if not modifier.has_field(b"simulation_bake_directory"):
+        return
+
+    mod_directory_ptr, mod_directory_field = modifier.get(
+        b"simulation_bake_directory", return_field=True
+    )
+
+    bakes = modifier.get_pointer(b"bakes")
+    if not bakes:
+        return
+
+    mod_bake_target = modifier.get(b"bake_target")
+
+    for bake_idx, bake in enumerate(iterators.dynamic_array(bakes)):
+        # Check for packed data.
+        bake_target = bake.get(b"bake_target")
+        if bake_target == cdefs.NODES_MODIFIER_BAKE_TARGET_INHERIT:
+            bake_target = mod_bake_target
+        if bake_target == cdefs.NODES_MODIFIER_BAKE_TARGET_PACKED:
+            # This data is packed in the blend file, it's not a dependency to trace.
+            continue
+
+        flag = bake.get(b"flag")
+        use_custom_directory = bool(flag & cdefs.NODES_MODIFIER_BAKE_CUSTOM_PATH)
+
+        if use_custom_directory:
+            bake_directory_ptr, bake_directory_field = bake.get(
+                b"directory", return_field=True
+            )
+            directory_ptr = bake_directory_ptr
+            field = bake_directory_field
+            block = bake
+        else:
+            directory_ptr = mod_directory_ptr
+            field = mod_directory_field
+            block = modifier
+
+        if not directory_ptr:
+            continue
+        directory = bake.bfile.dereference_pointer(directory_ptr)
+        if not directory:
+            continue
+
+        bpath = bpathlib.BlendPath(directory.as_bytes_string())
+        bake_block_name = block_name + b".bakes[%d]" % bake_idx
+
+        yield result.BlockUsage(
+            block,
+            bpath,
+            block_name=bake_block_name,
+            path_full_field=field,
+            is_sequence=True,
+        )