commoncode/src/commoncode/timeutils.py at main · aboutcode-org/commoncode · GitHub

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# SPDX-License-Identifier: Apache-2.0

# See http://www.apache.org/licenses/LICENSE-2.0 for the license text.

# See https://github.com/aboutcode-org/commoncode for support or download.

# See https://aboutcode.org for more information about nexB OSS projects.

from datetime import datetime

from datetime import tzinfo

from functools import update_wrapper

from functools import wraps

from time import time

"""

Time is of the essence: path safe time stamps creation and conversion to

datetime objects.

"""

class UTC(tzinfo):

"""UTC timezone"""

def utcoffset(self, dt): # NOQA

return None

def tzname(self, dt): # NOQA

return "UTC"

def dst(self, dt): # NOQA

return None

def time2tstamp(dt=None, path_safe=True):

"""

Return a timestamp representing the datetime object (assumed to be in UTC

time) or the current UTC time (if dt == None) formatted using the ISO 8601

standard as a basis, extended to be path safe is path_safe is True.

The Python isoformat returns a time stamp that complies with this standard

but has limitations when used in a file or directory name. Here we

transform the returned time stamp such that the result still complies with

the ISO standard and can be safely used as part of a of file or directory

name in a portable and OS safe fashion including on Windows where colons

are not allowed in file names, or on posix where / denotes a path segment

separator.

For times, the ISO 8601 format specifies either a colon : (extended format)

or nothing as a separator (basic format). Here Python defaults to using a

colon. We therefore remove all the colons to be safe across filesystems. (a

colon is not a valid path char on Windows)

Another character may show up in the ISO representation such as / for time

intervals. We could replace the forward slash with a double hyphen (--) as

a separator instead (see Section 4.4.2 of the ISO standard). However since

there are several places where hyphens are used, this makes it difficult to

parse back. Instead we use an _ (underscore) to make the time stamp easier

to convert back to a datetime object.

"""

# TODO: check that the dt is effectively in UTC

datim = dt or datetime.utcnow()

iso = datim.isoformat()

if path_safe:

iso = iso.replace(":", "").replace("/", "_")

return iso

def tstamp2time(stamp):

"""

Convert a UTC timestamp to a datetime object.

"""

# handle both basic and extended formats

tformat = "%Y-%m-%dT%H%M%S" if stamp[4] == "-" else "%Y%m%dT%H%M%S"

# normalize

dt_ms = stamp.strip().replace("Z", "").replace(":", "")

dt_ms = dt_ms.split(".")

isodatim = dt_ms[0]

datim = datetime.strptime(isodatim, tformat)

# all stamps must be UTC

datim = datim.replace(tzinfo=UTC())

# deal with optional microsec

try:

microsec = dt_ms[1]

except Exception:

microsec = None

if microsec:

microsec = int(microsec)

if 0 <= microsec <= 999999:

datim = datim.replace(microsecond=microsec)

return datim

def timed(fun):

"""

Decorate `fun` callable to return a tuple of (timing, result) where timing

is a function execution time in seconds as a float and result is the value

returned by calling `fun`.

Note: this decorator will not work as expected for functions that return

generators.

"""

@wraps(fun)

def _timed(*args, **kwargs):

start = time()

result = fun(*args, **kwargs)

return time() - start, result

return update_wrapper(_timed, fun)

commoncode/src/commoncode/timeutils.py at main · aboutcode-org/commoncode · GitHub

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