"""Utilities for working with files."""
+import contextlib
import datetime
import errno
+import glob
import hashlib
import logging
import os
-import io
import pathlib
+import re
import time
-from typing import Optional
-import glob
-from os.path import isfile, join, exists
-from typing import List
+from os.path import exists, isfile, join
+from typing import Callable, List, Literal, Optional, TextIO
from uuid import uuid4
-
logger = logging.getLogger(__name__)
+def remove_newlines(x: str) -> str:
+ return x.replace('\n', '')
+
+
+def strip_whitespace(x: str) -> str:
+ return x.strip()
+
+
+def remove_hash_comments(x: str) -> str:
+ return re.sub(r'#.*$', '', x)
+
+
+def slurp_file(
+ filename: str,
+ *,
+ skip_blank_lines=False,
+ line_transformers: Optional[List[Callable[[str], str]]] = None,
+):
+ ret = []
+ if not file_is_readable(filename):
+ raise Exception(f'{filename} can\'t be read.')
+ with open(filename) as rf:
+ for line in rf:
+ if line_transformers is not None:
+ for transformation in line_transformers:
+ line = transformation(line)
+ if skip_blank_lines and line == '':
+ continue
+ ret.append(line)
+ return ret
+
+
def remove(path: str) -> None:
"""Deletes a file. Raises if path refers to a directory or a file
that doesn't exist.
>>> os.path.exists(path)
True
"""
- logger.debug(f"Creating path {path}")
+ logger.debug("Creating path %s", path)
previous_umask = os.umask(0)
try:
os.makedirs(path)
return os.path.exists(filename) and os.path.isfile(filename)
+def file_is_readable(filename: str) -> bool:
+ return does_file_exist(filename) and os.access(filename, os.R_OK)
+
+
+def file_is_writable(filename: str) -> bool:
+ return does_file_exist(filename) and os.access(filename, os.W_OK)
+
+
+def file_is_executable(filename: str) -> bool:
+ return does_file_exist(filename) and os.access(filename, os.X_OK)
+
+
def does_directory_exist(dirname: str) -> bool:
"""Returns True if a file exists and is a directory.
def set_file_raw_atime(filename: str, atime: float):
mtime = get_file_raw_mtime(filename)
+ assert mtime is not None
os.utime(filename, (atime, mtime))
def set_file_raw_mtime(filename: str, mtime: float):
atime = get_file_raw_atime(filename)
+ assert atime is not None
os.utime(filename, (atime, mtime))
os.utime(filename, None)
-def convert_file_timestamp_to_datetime(
- filename: str, producer
-) -> Optional[datetime.datetime]:
+def convert_file_timestamp_to_datetime(filename: str, producer) -> Optional[datetime.datetime]:
ts = producer(filename)
if ts is not None:
return datetime.datetime.fromtimestamp(ts)
return get_file_timestamp_age_seconds(filename, lambda x: x.st_mtime)
-def get_file_timestamp_timedelta(
- filename: str, extractor
-) -> Optional[datetime.timedelta]:
+def get_file_timestamp_timedelta(filename: str, extractor) -> Optional[datetime.timedelta]:
age = get_file_timestamp_age_seconds(filename, extractor)
if age is not None:
return datetime.timedelta(seconds=float(age))
return get_file_timestamp_timedelta(filename, lambda x: x.st_mtime)
-def describe_file_timestamp(
- filename: str, extractor, *, brief=False
-) -> Optional[str]:
+def describe_file_timestamp(filename: str, extractor, *, brief=False) -> Optional[str]:
from datetime_utils import describe_duration, describe_duration_briefly
age = get_file_timestamp_age_seconds(filename, extractor)
return describe_file_timestamp(filename, lambda x: x.st_mtime, brief=brief)
-def touch_file(filename: str, *, mode: Optional[int] = 0o666) -> bool:
- return pathlib.Path(filename, mode=mode).touch()
+def touch_file(filename: str, *, mode: Optional[int] = 0o666):
+ pathlib.Path(filename, mode=mode).touch()
def expand_globs(in_filename: str):
yield file_or_directory
-class FileWriter(object):
+class FileWriter(contextlib.AbstractContextManager):
+ """A helper that writes a file to a temporary location and then moves
+ it atomically to its ultimate destination on close.
+
+ """
+
def __init__(self, filename: str) -> None:
self.filename = filename
uuid = uuid4()
self.tempfile = f'{filename}-{uuid}.tmp'
- self.handle = None
+ self.handle: Optional[TextIO] = None
- def __enter__(self) -> io.TextIOWrapper:
+ def __enter__(self) -> TextIO:
assert not does_path_exist(self.tempfile)
self.handle = open(self.tempfile, mode="w")
return self.handle
- def __exit__(self, exc_type, exc_val, exc_tb) -> bool:
+ def __exit__(self, exc_type, exc_val, exc_tb) -> Literal[False]:
if self.handle is not None:
self.handle.close()
cmd = f'/bin/mv -f {self.tempfile} {self.filename}'
ret = os.system(cmd)
if (ret >> 8) != 0:
- raise Exception(f'{cmd} failed, exit value {ret>>8}')
- return None
+ raise Exception(f'{cmd} failed, exit value {ret>>8}!')
+ return False
if __name__ == '__main__':