Add Chromium-only Blender WebEngine parity work

blender-5.2.0/scripts/modules/blend_render_info.py

@@ -0,0 +1,123 @@
+#!/usr/bin/env python3
+# SPDX-FileCopyrightText: 2010-2023 Blender Authors
+#
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+# This module can get render info without running from inside blender.
+
+
+__all__ = (
+    "read_blend_rend_chunk",
+)
+
+import _blendfile_header
+
+
+class RawBlendFileReader:
+    """
+    Return a file handle to the raw blend file data (abstracting compressed formats).
+    """
+    __slots__ = (
+        # The path to load.
+        "_filepath",
+        # The file base file handler or None (only set for compressed formats).
+        "_blendfile_base",
+        # The file handler to return to the caller (always uncompressed data).
+        "_blendfile",
+    )
+
+    def __init__(self, filepath):
+        self._filepath = filepath
+        self._blendfile_base = None
+        self._blendfile = None
+
+    def __enter__(self):
+        blendfile = open(self._filepath, "rb")
+        blendfile_base = None
+        head = blendfile.read(4)
+        blendfile.seek(0)
+        if head[0:2] == b'\x1f\x8b':  # GZIP magic.
+            import gzip
+            blendfile_base = blendfile
+            blendfile = gzip.open(blendfile, "rb")
+        elif head[0:4] == b'\x28\xb5\x2f\xfd':  # Z-standard magic.
+            import zstandard
+            blendfile_base = blendfile
+            blendfile = zstandard.open(blendfile, "rb")
+
+        self._blendfile_base = blendfile_base
+        self._blendfile = blendfile
+
+        return self._blendfile
+
+    def __exit__(self, _exc_type, _exc_value, _exc_traceback):
+        self._blendfile.close()
+        if self._blendfile_base is not None:
+            self._blendfile_base.close()
+
+        return False
+
+
+def get_render_info_structure(endian_str, size):
+    import struct
+    # The maximum size of the scene name changed over time, so create a different
+    # structure depending on the size of the entire block.
+    if size == 2 * 4 + 24:
+        return struct.Struct(endian_str + b'ii24s')
+    if size == 2 * 4 + 64:
+        return struct.Struct(endian_str + b'ii64s')
+    if size == 2 * 4 + 256:
+        return struct.Struct(endian_str + b'ii256s')
+    raise ValueError("Unknown REND chunk size: {:d}".format(size))
+
+
+def _read_blend_rend_chunk_from_file(blendfile, filepath):
+    import sys
+
+    from os import SEEK_CUR
+
+    try:
+        blender_header = _blendfile_header.BlendFileHeader(blendfile)
+    except _blendfile_header.BlendHeaderError:
+        sys.stderr.write("Not a blend file: {:s}\n".format(filepath))
+        return []
+
+    scenes = []
+
+    endian_str = b'<' if blender_header.is_little_endian else b'>'
+
+    block_header_struct = blender_header.create_block_header_struct()
+    while bhead := _blendfile_header.BlockHeader(blendfile, block_header_struct):
+        if bhead.code == b'ENDB':
+            break
+        remaining_bytes = bhead.size
+        if bhead.code == b'REND':
+            rend_block_struct = get_render_info_structure(endian_str, bhead.size)
+            start_frame, end_frame, scene_name = rend_block_struct.unpack(blendfile.read(rend_block_struct.size))
+            remaining_bytes -= rend_block_struct.size
+
+            scene_name = scene_name[:scene_name.index(b'\0')]
+            # It's possible old blend files are not UTF8 compliant, use `surrogateescape`.
+            scene_name = scene_name.decode("utf8", errors="surrogateescape")
+            scenes.append((start_frame, end_frame, scene_name))
+
+        blendfile.seek(remaining_bytes, SEEK_CUR)
+
+    return scenes
+
+
+def read_blend_rend_chunk(filepath):
+    with RawBlendFileReader(filepath) as blendfile:
+        return _read_blend_rend_chunk_from_file(blendfile, filepath)
+
+
+def main():
+    import sys
+
+    for filepath in sys.argv[1:]:
+        for value in read_blend_rend_chunk(filepath):
+            print("{:d} {:d} {:s}".format(*value))
+
+
+if __name__ == '__main__':
+    main()