Source code for openquake.hazardlib.speedups

# The Hazard Library
# Copyright (C) 2012-2014, GEM Foundation
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
"""
Module :mod:`openquake.hazardlib.speedups` contains internal utilities for
managing alternative implementation of the same functionality depending on
their availability.
"""
import inspect


[docs]class SpeedupsRegistry(object): """ Speedups registry allows to manage alternative implementations of functions. Typical use case for it is something like this: .. code-block:: python # in the module namespace def do_foo(foo, bar): # code in pure python ... def do_bar(baz, quux): # code in pure python ... # in the end of the module try: import _foobar_speedups except ImportError: import warnings warnings.warn("foobar speedups are not available", RuntimeWarning) else: from openquake.hazardlib import speedups def _c_do_foo(foo, bar): return _foobar_speedups.do_foo(foo, bar) speedups.register(do_foo, _c_do_foo) del _c_do_foo def _c_do_bar(baz, quux): return _foobar_speedups.do_foo(baz, quux) speedups.register(do_bar, _c_do_bar) del _c_do_bar Global registry is being used here. All speedups are enabled by default. In order to disable them, use :meth:`disable`. """ def __init__(self): self.enabled = True self.funcs = {}
[docs] def register(self, func, altfunc): """ Add a function and its alternative implementation to the registry. If registry is enabled, function code will be substituted by an alternative implementation immediately. :param func: A function object to patch. :param altfunc: An alternative implementation of the function. Must have the same signature and is supposed to behave exactly the same way as ``func``. """ assert inspect.getargspec(func) == inspect.getargspec(altfunc), \ "functions signatures are different in %s and %s" % \ (func, altfunc) self.funcs[func] = (func.__code__, altfunc.__code__) if self.enabled: # here we substitute the "func_code" attribute of the function, # which allows us not to worry of when and how is this function # being imported by other modules func.__code__ = altfunc.__code__
[docs] def enable(self): """ Set implementation to "alternative" for all the registered functions. """ for func in self.funcs: origcode, altcode = self.funcs[func] func.__code__ = altcode self.enabled = True
[docs] def disable(self): """ Set implementation to "original" for all the registered functions. """ for func in self.funcs: origcode, altcode = self.funcs[func] func.__code__ = origcode self.enabled = False
global_registry = SpeedupsRegistry() #: Global (default) registry :meth:`register`. register = global_registry.register #: Global (default) registry :meth:`enable`. enable = global_registry.enable #: Global (default) registry :meth:`disable`. disable = global_registry.disable