123 lines
3.3 KiB
Python
123 lines
3.3 KiB
Python
"""Helper functions."""
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from __future__ import absolute_import
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from __future__ import print_function
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import contextlib
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import os.path
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import shutil
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import sys
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import yaml
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from . import archival
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@contextlib.contextmanager
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def open_or_use_stdout(filename):
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"""Open the specified file for writing, or returns sys.stdout if filename is "-"."""
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if filename == "-":
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yield sys.stdout
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return
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line_buffered = 1
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try:
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fp = open(filename, "w", line_buffered)
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except IOError:
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print("Could not open file {}".format(filename), file=sys.stderr)
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sys.exit(1)
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try:
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yield fp
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finally:
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fp.close()
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def default_if_none(value, default):
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"""Set default if value is 'None'."""
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return value if value is not None else default
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def rmtree(path, **kwargs):
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"""Wrap shutil.rmtreee.
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Use a UTF-8 unicode path if Windows.
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See https://bugs.python.org/issue24672, where shutil.rmtree can fail with UTF-8.
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Use a bytes path to rmtree, otherwise.
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See https://github.com/pypa/setuptools/issues/706.
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"""
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if is_windows():
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if not isinstance(path, unicode):
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path = unicode(path, "utf-8")
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else:
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if isinstance(path, unicode):
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path = path.encode("utf-8")
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shutil.rmtree(path, **kwargs)
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def is_windows():
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"""Return True if Windows."""
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return sys.platform.startswith("win32") or sys.platform.startswith("cygwin")
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def remove_if_exists(path):
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"""Remove path if it exists."""
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if path is not None and os.path.exists(path):
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try:
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os.remove(path)
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except OSError:
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pass
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def is_string_list(lst):
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"""Return true if 'lst' is a list of strings, and false otherwise."""
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return isinstance(lst, list) and all(isinstance(x, basestring) for x in lst)
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def is_string_set(value):
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"""Return true if 'value' is a set of strings, and false otherwise."""
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return isinstance(value, set) and all(isinstance(x, basestring) for x in value)
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def is_js_file(filename):
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"""Return true if 'filename' ends in .js, and false otherwise."""
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return os.path.splitext(filename)[1] == ".js"
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def is_yaml_file(filename):
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"""Return true if 'filename' ends in .yml or .yaml, and false otherwise."""
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return os.path.splitext(filename)[1] in (".yaml", ".yml")
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def load_yaml_file(filename):
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"""Attempt to read 'filename' as YAML."""
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try:
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with open(filename, "r") as fp:
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return yaml.safe_load(fp)
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except yaml.YAMLError as err:
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raise ValueError("File '%s' contained invalid YAML: %s" % (filename, err))
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def dump_yaml_file(value, filename):
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"""Attempt to write YAML object to filename."""
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try:
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with open(filename, "w") as fp:
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return yaml.safe_dump(value, fp)
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except yaml.YAMLError as err:
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raise ValueError("Could not write YAML to file '%s': %s" % (filename, err))
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def dump_yaml(value):
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"""Return 'value' formatted as YAML."""
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# Use block (indented) style for formatting YAML.
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return yaml.safe_dump(value, default_flow_style=False).rstrip()
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def load_yaml(value):
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"""Attempt to parse 'value' as YAML."""
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try:
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return yaml.safe_load(value)
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except yaml.YAMLError as err:
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raise ValueError("Attempted to parse invalid YAML value '%s': %s" % (value, err))
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