Move the selection between the native and Python implementations of l…

…zo and lz4 to dissect.util (#16)

Co-authored-by: Jan Willem Brandenburg <[email protected]>

README.md

@@ -17,7 +17,17 @@ Information on the supported Python versions can be found in the Getting Started
 pip install dissect.btrfs
 ```
 
-This module is also automatically installed if you install the `dissect` package.
+This project decompresses lzo compressed file systems and can use the faster, native (C-based) lzo implementation when
+installed, instead of the slower pure Python implementation provided by `dissect.util`. To use these faster
+implementations, install the package with the lzo extra:
+
+```bash
+pip install "dissect.btrfs[lzo]"
+```
+
+Unfortunately there is no binary `python-lzo` wheel for PyPy installations on Windows, so it won't be installed there.
+
+This module including the lzo extra is also automatically installed if you install the `dissect` package.
 
 ## Build and test instructions
 

dissect/btrfs/stream.py

@@ -6,13 +6,9 @@
 from typing import TYPE_CHECKING, BinaryIO, NamedTuple
 from uuid import UUID
 
+from dissect.util.compression import lzo
 from dissect.util.stream import AlignedStream
 
-try:
- import lzo
-except ImportError:
- from dissect.util.compression import lzo
-
 try:
  import zstandard
 

pyproject.toml

@@ -37,14 +37,16 @@ repository = "https://github.com/fox-it/dissect.btrfs"
 
 [project.optional-dependencies]
 full = [
- # There are no Windows PyPy wheels available for python-lzo
- # So we use a pure python fallback for it.
- "python-lzo; platform_system != 'Windows' or platform_python_implementation != 'PyPy'",
  "zstandard",
 ]
 gcrc32 = [
  "google-crc32c",
 ]
+lzo = [
+ # There are no Windows PyPy wheels available for python-lzo
+ # So we use a pure python fallback for it.
+ "python-lzo; platform_system != 'Windows' or platform_python_implementation != 'PyPy'",
+]
 dev = [
  "dissect.btrfs[full]",
  "dissect.cstruct>=4.0.dev,<5.0.dev",