"""Utility methods for flake8."""
import collections
import fnmatch as _fnmatch
import inspect
import io
import os
import re
import sys
DIFF_HUNK_REGEXP = re.compile(r'^@@ -\d+(?:,\d+)? \+(\d+)(?:,(\d+))? @@.*$')
[docs]def parse_comma_separated_list(value):
# type: (Union[Sequence[str], str]) -> List[str]
"""Parse a comma-separated list.
:param value:
String or list of strings to be parsed and normalized.
:returns:
List of values with whitespace stripped.
:rtype:
list
"""
if not value:
return []
if not isinstance(value, (list, tuple)):
value = value.split(',')
return [item.strip() for item in value]
[docs]def normalize_paths(paths, parent=os.curdir):
# type: (Union[Sequence[str], str], str) -> List[str]
"""Parse a comma-separated list of paths.
:returns:
The normalized paths.
:rtype:
[str]
"""
return [normalize_path(p, parent)
for p in parse_comma_separated_list(paths)]
[docs]def normalize_path(path, parent=os.curdir):
# type: (str, str) -> str
"""Normalize a single-path.
:returns:
The normalized path.
:rtype:
str
"""
# NOTE(sigmavirus24): Using os.path.sep allows for Windows paths to
# be specified and work appropriately.
separator = os.path.sep
if separator in path:
path = os.path.abspath(os.path.join(parent, path))
return path.rstrip(separator)
[docs]def stdin_get_value():
# type: () -> str
"""Get and cache it so plugins can use it."""
cached_value = getattr(stdin_get_value, 'cached_stdin', None)
if cached_value is None:
stdin_value = sys.stdin.read()
if sys.version_info < (3, 0):
cached_type = io.BytesIO
else:
cached_type = io.StringIO
stdin_get_value.cached_stdin = cached_type(stdin_value)
cached_value = stdin_get_value.cached_stdin
return cached_value.getvalue()
[docs]def parse_unified_diff(diff=None):
# type: (str) -> List[str]
"""Parse the unified diff passed on stdin.
:returns:
dictionary mapping file names to sets of line numbers
:rtype:
dict
"""
# Allow us to not have to patch out stdin_get_value
if diff is None:
diff = stdin_get_value()
number_of_rows = None
current_path = None
parsed_paths = collections.defaultdict(set)
for line in diff.splitlines():
if number_of_rows:
# NOTE(sigmavirus24): Below we use a slice because stdin may be
# bytes instead of text on Python 3.
if line[:1] != '-':
number_of_rows -= 1
# We're in the part of the diff that has lines starting with +, -,
# and ' ' to show context and the changes made. We skip these
# because the information we care about is the filename and the
# range within it.
# When number_of_rows reaches 0, we will once again start
# searching for filenames and ranges.
continue
# NOTE(sigmavirus24): Diffs that we support look roughly like:
# diff a/file.py b/file.py
# ...
# --- a/file.py
# +++ b/file.py
# Below we're looking for that last line. Every diff tool that
# gives us this output may have additional information after
# ``b/file.py`` which it will separate with a \t, e.g.,
# +++ b/file.py\t100644
# Which is an example that has the new file permissions/mode.
# In this case we only care about the file name.
if line[:3] == '+++':
current_path = line[4:].split('\t', 1)[0]
# NOTE(sigmavirus24): This check is for diff output from git.
if current_path[:2] == 'b/':
current_path = current_path[2:]
# We don't need to do anything else. We have set up our local
# ``current_path`` variable. We can skip the rest of this loop.
# The next line we will see will give us the hung information
# which is in the next section of logic.
continue
hunk_match = DIFF_HUNK_REGEXP.match(line)
# NOTE(sigmavirus24): pep8/pycodestyle check for:
# line[:3] == '@@ '
# But the DIFF_HUNK_REGEXP enforces that the line start with that
# So we can more simply check for a match instead of slicing and
# comparing.
if hunk_match:
(row, number_of_rows) = [
1 if not group else int(group)
for group in hunk_match.groups()
]
parsed_paths[current_path].update(
range(row, row + number_of_rows)
)
# We have now parsed our diff into a dictionary that looks like:
# {'file.py': set(range(10, 16), range(18, 20)), ...}
return parsed_paths
[docs]def is_windows():
# type: () -> bool
"""Determine if we're running on Windows.
:returns:
True if running on Windows, otherwise False
:rtype:
bool
"""
return os.name == 'nt'
[docs]def can_run_multiprocessing_on_windows():
# type: () -> bool
"""Determine if we can use multiprocessing on Windows.
:returns:
True if the version of Python is modern enough, otherwise False
:rtype:
bool
"""
is_new_enough_python27 = sys.version_info >= (2, 7, 11)
is_new_enough_python3 = sys.version_info > (3, 2)
return is_new_enough_python27 or is_new_enough_python3
[docs]def is_using_stdin(paths):
# type: (List[str]) -> bool
"""Determine if we're going to read from stdin.
:param list paths:
The paths that we're going to check.
:returns:
True if stdin (-) is in the path, otherwise False
:rtype:
bool
"""
return '-' in paths
def _default_predicate(*args):
return False
[docs]def filenames_from(arg, predicate=None):
# type: (str, callable) -> Generator
"""Generate filenames from an argument.
:param str arg:
Parameter from the command-line.
:param callable predicate:
Predicate to use to filter out filenames. If the predicate
returns ``True`` we will exclude the filename, otherwise we
will yield it. By default, we include every filename
generated.
:returns:
Generator of paths
"""
if predicate is None:
predicate = _default_predicate
if os.path.isdir(arg):
for root, sub_directories, files in os.walk(arg):
if predicate(root):
sub_directories[:] = []
continue
# NOTE(sigmavirus24): os.walk() will skip a directory if you
# remove it from the list of sub-directories.
for directory in sub_directories:
joined = os.path.join(root, directory)
if predicate(directory) or predicate(joined):
sub_directories.remove(directory)
for filename in files:
joined = os.path.join(root, filename)
if predicate(joined) or predicate(filename):
continue
yield joined
else:
yield arg
[docs]def fnmatch(filename, patterns, default=True):
# type: (str, List[str], bool) -> bool
"""Wrap :func:`fnmatch.fnmatch` to add some functionality.
:param str filename:
Name of the file we're trying to match.
:param list patterns:
Patterns we're using to try to match the filename.
:param bool default:
The default value if patterns is empty
:returns:
True if a pattern matches the filename, False if it doesn't.
``default`` if patterns is empty.
"""
if not patterns:
return default
return any(_fnmatch.fnmatch(filename, pattern) for pattern in patterns)
[docs]def parameters_for(plugin):
# type: (flake8.plugins.manager.Plugin) -> List[str]
"""Return the parameters for the plugin.
This will inspect the plugin and return either the function parameters
if the plugin is a function or the parameters for ``__init__`` after
``self`` if the plugin is a class.
:param plugin:
The internal plugin object.
:type plugin:
flake8.plugins.manager.Plugin
:returns:
Parameters to the plugin.
:rtype:
list(str)
"""
func = plugin.plugin
is_class = not inspect.isfunction(func)
if is_class: # The plugin is a class
func = plugin.plugin.__init__
if sys.version_info < (3, 3):
parameters = inspect.getargspec(func)[0]
else:
parameters = [
parameter.name
for parameter in inspect.signature(func).parameters.values()
if parameter.kind == parameter.POSITIONAL_OR_KEYWORD
]
if is_class:
parameters.remove('self')
return parameters