Source code for guidata.utils
# -*- coding: utf-8 -*-
#
# Copyright © 2009-2010 CEA
# Pierre Raybaut
# Licensed under the terms of the CECILL License
# (see guidata/__init__.py for details)
"""
utils
-----
The ``guidata.utils`` module provides various utility helper functions
(pure python).
"""
import sys, time, subprocess, os, os.path as osp
# Findout the encoding used for stdout or use ascii as default
stdout_encoding = "ascii"
if hasattr(sys.stdout, "encoding"):
if sys.stdout.encoding:
stdout_encoding = sys.stdout.encoding
[docs]def min_equals_max(min, max):
"""
Return True if minimium value equals maximum value
Return False if not, or if maximum or minimum value is not defined
"""
return min is not None and max is not None and min==max
[docs]def pairs(iterable):
"""A simple generator that takes a list and generates
pairs [ (l[0],l[1]), ..., (l[n-2], l[n-1])]
"""
it = iter(iterable)
first = it.next()
while True:
second = it.next()
yield (first,second)
first = second
[docs]def utf8_to_unicode(string):
"""
Convert UTF-8 string to Unicode
"""
if not isinstance(string, basestring):
string = unicode(string)
if not isinstance(string, unicode):
try:
string = unicode(string, "utf-8")
except UnicodeDecodeError, error:
message = "String %r is not UTF-8 encoded"
raise UnicodeDecodeError(message % string, *error.args[1:])
return string
[docs]def unicode_to_stdout(ustr):
"""convert a unicode string to a byte string encoded
for stdout output"""
return ustr.encode(stdout_encoding, "replace")
[docs]def update_dataset(dest, source, visible_only=False):
"""
Update `dest` dataset items from `source` dataset
dest should inherit from DataSet, whereas source can be any
Python object containing matching attribute names.
For each DataSet item, the function will try to get the attribute
of the same name from the source.
visible_only: if True, update only visible items
"""
for item in dest._items:
if hasattr(source, item._name):
try:
hide = item.get_prop_value("display", source, "hide", False)
except AttributeError:
#FIXME: Remove this try...except
hide = False
if visible_only and hide:
continue
setattr(dest, item._name, getattr(source, item._name))
[docs]def restore_dataset(source, dest):
"""
Restore `dest` dataset items from `source` dataset
This function is almost the same as update_dataset but requires
the source to be a DataSet instead of the destination.
"""
for item in source._items:
if hasattr(dest, item._name):
setattr(dest, item._name, getattr(source, item._name))
[docs]def assert_interface_supported(klass, iface):
"""Makes sure a class supports an interface"""
for name, func in iface.__dict__.items():
if name == '__inherits__':
continue
if callable(func):
assert hasattr(klass, name), "Attribute %s missing from %r" % (name,klass)
imp_func = getattr(klass, name)
imp_code = imp_func.func_code
code = func.func_code
imp_nargs = imp_code.co_argcount
nargs = code.co_argcount
if imp_code.co_varnames[:imp_nargs] != code.co_varnames[:nargs]:
assert False, "Arguments of %s.%s differ from interface: %r!=%r" % (
klass.__name__, imp_func.func_name,
imp_func.func_code.co_varnames[:imp_nargs],
func.func_code.co_varnames[:nargs]
)
else:
pass # should check class attributes for consistency
[docs]def assert_interfaces_valid(klass):
"""Makes sure a class supports the interfaces
it declares"""
assert hasattr(klass, "__implements__"), "Class doesn't implements anything"
for iface in klass.__implements__:
assert_interface_supported(klass, iface)
if hasattr(iface, "__inherits__"):
base = iface.__inherits__()
assert issubclass(klass, base), "%s should be a subclass of %s" % (klass, base)
[docs]def add_extension(item, value):
"""
Add extension to filename
`item`: data item representing a file path
`value`: possible value for data item
"""
value = unicode(value)
formats = item.get_prop("data", "formats")
if len(formats) == 1 and formats[0] != '*':
if not value.endswith('.'+formats[0]) and len(value) > 0:
return value+'.'+formats[0]
return value
[docs]def bind(fct, v):
"""
Returns a callable representing the function 'fct' with it's
first argument bound to the value v
if g = bind(f,1) and f is a function of x,y,z
then g(y,z) will return f(1,y,z)
"""
def cb(*args, **kwargs):
return fct(v, *args, **kwargs)
return cb
def localtime_to_isodate(time_struct):
s = time.strftime("%Y-%m-%d %H:%M:%S ", time_struct)
s += "%+05d" % time.timezone
return s
def isodate_to_localtime(s):
return time.strptime(s[:16], "%Y-%m-%d %H:%M:%S")
format_hms = FormatTime()
[docs]class Timer(object):
"""MATLAB-like timer: tic, toc"""
def __init__(self):
self.cl = {}
def tic(self, cat):
print ">", cat
self.cl[cat] = time.clock()
def toc(self, cat, msg="delta:"):
print "<", cat, ":", msg, time.clock()-self.cl[cat]
_tm = Timer()
tic = _tm.tic
toc = _tm.toc
[docs]def is_program_installed(basename, get_path=False):
"""Return True if program is installed and present in PATH"""
for path in os.environ["PATH"].split(os.pathsep):
abspath = osp.join(path, basename)
if osp.isfile(abspath):
if get_path:
return abspath
else:
return True
else:
return False
[docs]def run_program(name, args='', cwd=None, shell=True, wait=False):
"""Run program in a separate process"""
path = is_program_installed(name, get_path=True)
if not path:
raise RuntimeError("Program %s was not found" % name)
command = [path]
if args:
command.append(args)
if wait:
subprocess.call(" ".join(command), cwd=cwd, shell=shell)
else:
subprocess.Popen(" ".join(command), cwd=cwd, shell=shell)
[docs]def is_module_available(module_name):
"""Return True if Python module is available"""
try:
__import__(module_name)
return True
except ImportError:
return False
[docs]def trace(f):
"""A decorator that traces function entry/exit
used for debugging only
"""
from functools import wraps
@wraps(f)
def wrapper(*args,**kwargs):
print "enter:", f.__name__
res = f(*args,**kwargs)
print "leave:", f.__name__
return res
return wrapper