Formatting and code fixes

- Fix code formatting issues
- Remove unused imports
- Fix undefined reference to ZstdFile when pyzstd missing

Author: vanandrew

nibabel/analyze.py

@@ -95,6 +95,7 @@
 from .fileholders import copy_file_map
 from .batteryrunners import Report
 from .arrayproxy import ArrayProxy
+from .openers import HAVE_ZSTD
 
 # Sub-parts of standard analyze header from
 # Mayo dbh.h file
@@ -907,11 +908,8 @@ class AnalyzeImage(SpatialImage):
     files_types = (('image', '.img'), ('header', '.hdr'))
     valid_exts = ('.img', '.hdr')
     _compressed_suffixes = ('.gz', '.bz2')
-    try: # If pyzstd installed., add .zst suffix
-        import pyzstd
+    if HAVE_ZSTD:  # If pyzstd installed., add .zst suffix
         _compressed_suffixes = (*_compressed_suffixes, '.zst')
-    except ImportError:
-        pass
 
     makeable = True
     rw = True

nibabel/benchmarks/bench_fileslice.py

@@ -14,17 +14,11 @@
 import numpy as np
 
 from io import BytesIO
-from ..openers import ImageOpener
+from ..openers import ImageOpener, HAVE_ZSTD
 from ..fileslice import fileslice
 from ..rstutils import rst_table
 from ..tmpdirs import InTemporaryDirectory
 
-try:
-    import pyzstd
-    ZSTD_INSTALLED = True
-except ImportError:
-    ZSTD_INSTALLED = False
-
 SHAPE = (64, 64, 32, 100)
 ROW_NAMES = [f'axis {i}, len {dim}' for i, dim in enumerate(SHAPE)]
 COL_NAMES = ['mid int',
@@ -110,7 +104,7 @@ def my_table(title, times, base):
         my_table('bz2 slice - raw (ratio)',
                  np.dstack((bz2_times, bz2_times / bz2_base)),
                  bz2_base)
-    if ZSTD_INSTALLED:
+    if HAVE_ZSTD:
         if zst:
             with InTemporaryDirectory():
                 zst_times, zst_base = run_slices('data.zst', repeat)

nibabel/brikhead.py

@@ -43,6 +43,7 @@
     ImageDataError
 )
 from .volumeutils import Recoder
+from .openers import HAVE_ZSTD
 
 # used for doc-tests
 filepath = os.path.dirname(os.path.realpath(__file__))
@@ -491,14 +492,11 @@ class AFNIImage(SpatialImage):
     valid_exts = ('.brik', '.head')
     files_types = (('image', '.brik'), ('header', '.head'))
     _compressed_suffixes = ('.gz', '.bz2', '.Z')
+    if HAVE_ZSTD:  # If pyzstd installed., add .zst suffix
+        _compressed_suffixes = (*_compressed_suffixes, '.zst')
     makeable = False
     rw = False
     ImageArrayProxy = AFNIArrayProxy
-    try: # If pyzstd installed., add .zst suffix
-        import pyzstd
-        _compressed_suffixes = (*_compressed_suffixes, '.zst')
-    except ImportError:
-        pass
 
     @classmethod
     def from_file_map(klass, file_map, *, mmap=True, keep_file_open=None):

nibabel/loadsave.py

@@ -13,18 +13,15 @@
 import numpy as np
 
 from .filename_parser import splitext_addext, _stringify_path
-from .openers import ImageOpener
+from .openers import ImageOpener, HAVE_ZSTD
 from .filebasedimages import ImageFileError
 from .imageclasses import all_image_classes
 from .arrayproxy import is_proxy
 from .deprecated import deprecate_with_version
 
 _compressed_suffixes = ('.gz', '.bz2')
-try: # If pyzstd installed., add .zst suffix
-    import pyzstd
+if HAVE_ZSTD:  # If pyzstd installed., add .zst suffix
     _compressed_suffixes = (*_compressed_suffixes, '.zst')
-except ImportError:
-    pass
 
 def load(filename, **kwargs):
     r""" Load file given filename, guessing at file type

nibabel/minc1.py

@@ -16,6 +16,7 @@
 
 from .spatialimages import SpatialHeader, SpatialImage
 from .fileslice import canonical_slicers
+from .openers import HAVE_ZSTD
 
 _dt_dict = {
     ('b', 'unsigned'): np.uint8,
@@ -317,11 +318,8 @@ class Minc1Image(SpatialImage):
     valid_exts = ('.mnc',)
     files_types = (('image', '.mnc'),)
     _compressed_suffixes = ('.gz', '.bz2')
-    try: # If pyzstd installed., add .zst suffix
-        import pyzstd
+    if HAVE_ZSTD:  # If pyzstd installed., add .zst suffix
         _compressed_suffixes = (*_compressed_suffixes, '.zst')
-    except ImportError:
-        pass
 
     makeable = True
     rw = False

nibabel/openers.py

@@ -42,8 +42,9 @@
 # Enable .zst support if pyzstd installed.
 try:
     from pyzstd import ZstdFile
+    HAVE_ZSTD = True
 except ImportError:
-    pass
+    HAVE_ZSTD = False
 
 def _gzip_open(filename, mode='rb', compresslevel=9, keep_open=False):
 
@@ -82,19 +83,21 @@ class Opener(object):
     """
     gz_def = (_gzip_open, ('mode', 'compresslevel', 'keep_open'))
     bz2_def = (BZ2File, ('mode', 'buffering', 'compresslevel'))
-    zstd_def = (ZstdFile, ('mode', 'level_or_option'))
     compress_ext_map = {
         '.gz': gz_def,
         '.bz2': bz2_def,
-        '.zst': zstd_def,
         None: (open, ('mode', 'buffering'))  # default
     }
+    if HAVE_ZSTD:  # add zst to ext map, if library exists
+        zstd_def = (ZstdFile, ('mode', 'level_or_option'))
+        compress_ext_map['.zst'] = zstd_def
     #: default compression level when writing gz and bz2 files
     default_compresslevel = 1
     #: default option for zst files
     default_zst_compresslevel = 3
     default_level_or_option = {"rb": None, "r": None,
-        "wb": default_zst_compresslevel, "w": default_zst_compresslevel}
+                               "wb": default_zst_compresslevel,
+                               "w": default_zst_compresslevel}
     #: whether to ignore case looking for compression extensions
     compress_ext_icase = True