Start of dependency tracer work.

blender_asset_tracer/tracer/__init__.py

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+import logging
+import pathlib
+import typing
+
+from blender_asset_tracer import bpathlib, blendfile
+from . import result, blocks
+
+log = logging.getLogger(__name__)
+
+codes_to_skip = {
+    b'LI',  # Library blocks we handle after the blend file itself.
+    b'ID', b'WM', b'SN',  # These blocks never have external assets.
+}
+
+
+def deps(bfilepath: pathlib.Path) -> typing.Iterator[result.BlockUsage]:
+    log.info('Tracing %s', bfilepath)
+
+    with blendfile.BlendFile(bfilepath) as bfile:
+        for block in asset_holding_blocks(bfile):
+            yield from blocks.from_block(block)
+
+        # TODO: handle library blocks for recursion.
+
+
+def asset_holding_blocks(bfile: blendfile.BlendFile) -> typing.Iterator[blendfile.BlendFileBlock]:
+    for block in bfile.blocks:
+        assert isinstance(block, blendfile.BlendFileBlock)
+        code = block.code
+
+        # The longer codes are either arbitrary data or data blocks that
+        # don't refer to external assets. The former data blocks will be
+        # visited when we hit the two-letter datablocks that use them.
+        if len(code) > 2 or code in codes_to_skip:
+            continue
+
+        yield block

blender_asset_tracer/tracer/blocks.py

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+import logging
+import sys
+import typing
+
+from blender_asset_tracer import blendfile
+from . import result, cdefs
+
+log = logging.getLogger(__name__)
+
+_warned_about_types = set()
+
+
+class NoReaderImplemented(NotImplementedError):
+    """There is no reader implementation for a specific block code."""
+
+    def __init__(self, message: str, code: bytes):
+        super().__init__(message)
+        self.code = code
+
+
+def from_block(block: blendfile.BlendFileBlock) -> typing.Iterator[result.BlockUsage]:
+    assert block.code != b'DATA'
+
+    module = sys.modules[__name__]
+    funcname = '_from_block_' + block.code.decode().lower()
+    try:
+        block_reader = getattr(module, funcname)
+    except AttributeError:
+        if block.code not in _warned_about_types:
+            log.warning('No reader implemented for block type %r', block.code.decode())
+            _warned_about_types.add(block.code)
+        return
+
+    yield from block_reader(block)
+
+
+def _from_block_im(block: blendfile.BlendFileBlock) -> typing.Iterator[result.BlockUsage]:
+    # old files miss this
+    image_source = block.get(b'source', default=cdefs.IMA_SRC_FILE)
+    if image_source not in {cdefs.IMA_SRC_FILE, cdefs.IMA_SRC_SEQUENCE, cdefs.IMA_SRC_MOVIE}:
+        return
+    if block[b'packedfile']:
+        return
+
+    pathname, field = block.get(b'name', return_field=True)
+
+    # TODO: the receiver should inspect the 'source' property too, and if set
+    # to cdefs.IMA_SRC_SEQUENCE yield the entire sequence of files.
+    yield result.BlockUsage(block, field, pathname)

blender_asset_tracer/tracer/cdefs.py

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+# ***** BEGIN GPL LICENSE BLOCK *****
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software Foundation,
+# Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+#
+# ***** END GPL LICENCE BLOCK *****
+
+"""Constants defined in C."""
+
+# DNA_sequence_types.h (Sequence.type)
+SEQ_TYPE_IMAGE = 0
+SEQ_TYPE_META = 1
+SEQ_TYPE_SCENE = 2
+SEQ_TYPE_MOVIE = 3
+SEQ_TYPE_SOUND_RAM = 4
+SEQ_TYPE_SOUND_HD = 5
+SEQ_TYPE_MOVIECLIP = 6
+SEQ_TYPE_MASK = 7
+SEQ_TYPE_EFFECT = 8
+
+IMA_SRC_FILE = 1
+IMA_SRC_SEQUENCE = 2
+IMA_SRC_MOVIE = 3
+
+# DNA_modifier_types.h
+eModifierType_MeshCache = 46
+
+# DNA_particle_types.h
+PART_DRAW_OB = 7
+PART_DRAW_GR = 8
+
+# DNA_object_types.h
+# Object.transflag
+OB_DUPLIGROUP = 1 << 8
+
+CACHE_LIBRARY_SOURCE_CACHE = 1

blender_asset_tracer/tracer/result.py

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+
+
+class BlockUsage:
+    """Represents the use of an asset by a data block.
+
+    :ivar block:
+    :type block: blendfile.BlendFileBlock
+    :ivar field:
+    :type field: dna.Field
+    :ivar asset_path:
+    :type asset_path: bpathlib.BlendPath
+    """
+
+    def __init__(self, block, field, asset_path):
+        self.block_idname = block[b'id', b'name']
+
+        from blender_asset_tracer import blendfile, bpathlib
+        from blender_asset_tracer.blendfile import dna
+
+        assert isinstance(block, blendfile.BlendFileBlock)
+        assert isinstance(field, dna.Field), 'field should be dna.Field, not %r' % type(field)
+        assert isinstance(asset_path, (bytes, bpathlib.BlendPath)), \
+            'asset_path should be BlendPath, not %r' % type(asset_path)
+
+        if isinstance(asset_path, bytes):
+            asset_path = bpathlib.BlendPath(asset_path)
+
+        self.block = block
+        self.field = field
+        self.asset_path = asset_path
+
+    def __repr__(self):
+        return '<BlockUsage name=%r type=%r field=%r asset=%r>' % (
+            self.block_idname, self.block.dna_type_name,
+            self.field.name.name_full.decode(), self.asset_path)