#! /usr/bin/env python
"""General utilities."""
from __future__ import print_function
import os
import sys
import subprocess
import types
import tempfile
import shutil
import glob
import re
import string
from distutils.dir_util import mkpath
from .errors import MissingFileError
[docs]class cd(object):
"""Context for changing the working directory."""
def __init__(self, dir):
"""Create a new working directory context.
If *dir* does not exist, it (along with it's parents) will be
created.
Parameters
----------
dir : str
Path to the working directory.
"""
self._dir = dir
self._starting_dir = None
def __enter__(self):
"""Change to new working directory.
Returns
-------
str
Absolute path of new working directory.
"""
self._starting_dir = os.path.abspath(os.getcwd())
if not os.path.isdir(self._dir):
mkpath(self._dir)
os.chdir(self._dir)
return os.path.abspath(os.getcwd())
def __exit__(self, ex_type, ex_value, traceback):
"""Change to original working directory."""
os.chdir(self._starting_dir)
[docs]class cdtemp(object):
"""Context that creates a temporary working directory."""
def __init__(self, **kwds):
"""Create a temporary directory context.
The keywords are the same as those for ``tempfile.mkdtemp``. After
exiting the context, the temporary directory is removed.
See Also
--------
mktemp
"""
self._kwds = kwds
self._starting_dir = None
self._tmp_dir = None
def __enter__(self):
"""Change to new temporary directory.
Returns
-------
str
Absolute path of temporary directory.
"""
self._starting_dir = os.path.abspath(os.getcwd())
self._tmp_dir = tempfile.mkdtemp(**self._kwds)
os.chdir(self._tmp_dir)
return os.path.abspath(self._tmp_dir)
def __exit__(self, ex_type, ex_value, traceback):
"""Change to original working directory and clean up."""
os.chdir(self._starting_dir)
shutil.rmtree(self._tmp_dir)
[docs]class mktemp(object):
"""Context that creates a temporary directory."""
def __init__(self, **kwds):
"""Create a temporary directory context.
The keywords are the same as those for ``tempfile.mkdtemp``. After
exiting the context, the temporary directory is removed. This is the
same as :func:`cdtemp` except that the working directory is not
changed while in the context.
See Also
--------
cdtemp
"""
self._kwds = kwds
self._tmp_dir = None
def __enter__(self):
"""Make temporary directory.
Returns
-------
str
Absolute path of temporary directory.
"""
self._tmp_dir = tempfile.mkdtemp(**self._kwds)
return os.path.abspath(self._tmp_dir)
def __exit__(self, ex_type, ex_value, traceback):
"""Remove temporary directory."""
shutil.rmtree(self._tmp_dir)
[docs]def mkdir_p(path):
try:
os.makedirs(path)
except OSError as err:
if err.errno == os.errno.EEXIST and os.path.isdir(path):
pass
else:
raise
return os.path.abspath(path)
[docs]def glob_cp(pattern, dest):
if not os.path.isdir(dest):
raise ValueError('{dest}: not a directory'.format(dest=dest))
for fname in glob.glob(pattern):
status('cp {src} {dest}'.format(src=fname, dest=dest))
shutil.copy2(fname, dest)
[docs]def sub(fname, subs, inplace=False):
old, new = subs
with open(fname, 'r') as fp:
contents = fp.read()
contents = re.sub(old, new, contents)
if inplace:
shutil.copy2(fname, fname + '.bak')
with open(fname, 'w') as fp:
fp.write(contents)
else:
return contents
[docs]def glob_sub(pattern, subs):
old, new = subs
for fname in glob.glob(pattern):
sub(fname, (old, new), inplace=True)
[docs]def status(message):
"""Print a status message.
Parameters
----------
message : str
Status message.
"""
print(' '.join(['==>', message]), file=sys.stderr)
[docs]def check_output(*args, **kwds):
"""Execute a shell command.
This is the same as the ``subprocess.check_output`` command available in
Python versions greater than 2.7 but is provided for pre-2.7 versions.
"""
kwds.setdefault('stdout', subprocess.PIPE)
return subprocess.Popen(*args, **kwds).communicate()[0]
[docs]def system(*args, **kwds):
"""Execute and echo a shell command.
Parameters
----------
verbose : boolean
Print ouput.
"""
verbose = kwds.pop('verbose', True)
kwds.setdefault('stdout', sys.stderr)
status(' '.join(args[0]))
if verbose:
call = subprocess.check_call
else:
call = check_output
try:
call(*args, **kwds)
except subprocess.CalledProcessError:
status('Error')
raise
[docs]def which(prog, env=None):
"""Look for a program.
Use the system ``which`` command to look for a program. If provided,
*env* is the name of a environment variable that may give the path to
the program.
Parameters
----------
prog : str
Name of a program.
env : str
Look for program in a user environment.
Returns
-------
str
The absolute path to the program.
"""
prog = os.environ.get(env or prog.upper(), prog)
try:
prog = check_output(['which', prog],
stderr=open('/dev/null', 'w')).strip()
except subprocess.CalledProcessError:
return None
else:
return prog
[docs]def pkg_config(name, opts):
"""Execute the pkg-config command.
Parameters
----------
name : str
Name of a pkg-config package.
opts : str or iterable
Command-line options to pass to pkg-config.
Returns
-------
str
Result of calling ``pkg-config``.
"""
if isinstance(opts, types.StringTypes):
opts = [opts]
try:
flags = check_output([which('pkg-config')] + opts + [name],
stderr=open('/dev/null', 'w')).strip()
except subprocess.CalledProcessError:
return None
else:
return flags
[docs]def read_first_of(files):
"""Read the first file found.
Parameters
----------
files : iterable
Ordered list of files to read.
Returns
-------
(str, str)
Name of the first file found and then contents of that file.
"""
for name in files:
try:
with open(name, 'r') as file_like:
return (os.path.abspath(name), file_like.read())
except IOError:
pass
raise MissingFileError(', '.join(files))
TEXT_CHARACTERS = ''.join(map(chr, range(32, 127)) + list("\n\r\t\b"))
NULL_TRANS = string.maketrans("", "")
[docs]def is_text_file(fname, block=1024):
"""Check if a file is text or binary."""
with open(fname, 'r') as fp:
return is_text(fp.read(block))
[docs]def is_text(buff):
"""Check if a string is text or binary."""
if '\0' in buff:
return False
if len(buff) == 0:
return True
bin_chars = buff.translate(NULL_TRANS, TEXT_CHARACTERS)
if len(bin_chars) > len(buff) * 0.3:
return False
return True
