# -*- coding: utf-8 -*-
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# The MIT License (MIT)
#
# Copyright (c) 2014 Jonathan Labéjof <jonathan.labejof@gmail.com>
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"""Code from http://code.activestate.com/recipes/277940-decorator-for-\
bindingconstants-at-compile-time/
Decorator for automatic code optimization.
If a global is known at compile time, replace it with a constant.
Fold tuples of constants into a single constant.
Fold constant attribute lookups into a single constant.
Modifications:
- Add constants values from opmap constants (STORE_GLOBAL, etc.) in order to
avoid to update globals.
- Modify verbose argument which is None or use a function with one argument
which can be bound to a print function or a logging function.
- Set attributes from originary function such as __dict__, __module__, etc."""
from opcode import opmap, HAVE_ARGUMENT, EXTENDED_ARG
from types import FunctionType, ModuleType
from functools import reduce
from six import exec_, PY3
from six.moves import builtins
__all__ = [
'SAFE_BUILTINS', 'safe_eval', 'safe_exec', 'bind_all', 'make_constants',
'singleton_per_scope', 'getcodeobj'
]
BUILTIN_IO_PROPS = [
'open', '__name__', '__debug__', '__doc__', '__import__', '__package__',
'compile', 'copyright', 'credits', 'eval', 'execfile', 'exit', 'file',
'globals', 'help', 'input', 'intern', 'license', 'locals', 'open', 'print',
'quit', 'raw_input', 'reload'
] #: set of builtin objects to remove from a safe builtin.
SINGLETONS_PER_SCOPES = {}
[docs]def singleton_per_scope(_cls, _scope=None, _renew=False, *args, **kwargs):
"""Instanciate a singleton per scope."""
result = None
singletons = SINGLETONS_PER_SCOPES.setdefault(_scope, {})
if _renew or _cls not in singletons:
singletons[_cls] = _cls(*args, **kwargs)
result = singletons[_cls]
return result
def _safebuiltins():
"""Construct a safe builtin environment without I/O functions.
:rtype: dict"""
result = {}
objectnames = [
objectname for objectname in dir(builtins)
if objectname not in BUILTIN_IO_PROPS
]
for objectname in objectnames:
result[objectname] = getattr(builtins, objectname)
return result
SAFE_BUILTINS = {'__builtins__': _safebuiltins()} #: safe builtins.
def _safe_processing(nsafefn, source, _globals=None, _locals=None):
"""Do a safe processing of input fn in using SAFE_BUILTINS.
:param fn: function to call with input parameters.
:param source: source object to process with fn.
:param dict _globals: global objects by name.
:param dict _locals: local objects by name.
:return: fn processing result"""
if _globals is None:
_globals = SAFE_BUILTINS
else:
_globals.update(SAFE_BUILTINS)
return nsafefn(source, _globals, _locals)
[docs]def safe_eval(source, _globals=None, _locals=None):
"""Process a safe evaluation."""
return _safe_processing(eval, source, _globals, _locals)
[docs]def safe_exec(source, _globals=None, _locals=None):
"""Do a safe python execution."""
return _safe_processing(exec_, source, _globals, _locals)
STORE_GLOBAL = opmap['STORE_GLOBAL']
LOAD_GLOBAL = opmap['LOAD_GLOBAL']
LOAD_CONST = opmap['LOAD_CONST']
LOAD_ATTR = opmap['LOAD_ATTR']
BUILD_TUPLE = opmap['BUILD_TUPLE']
JUMP_FORWARD = opmap['JUMP_FORWARD']
WRAPPER_ASSIGNMENTS = ('__doc__', '__annotations__', '__dict__', '__module__')
def _make_constants(func, builtin_only=False, stoplist=None, verbose=None):
"""Generate new function where code is an input function code with all
LOAD_GLOBAL statements changed to LOAD_CONST statements.
:param function func: code function to transform.
:param bool builtin_only: only transform builtin objects.
:param list stoplist: attribute names to not transform.
:param function verbose: logger function which takes in parameter a message
.. warning::
Be sure global attributes to transform are not resolved dynamically."""
result = func
if stoplist is None:
stoplist = []
try:
fcode = func.__code__
except AttributeError:
return func # Jython doesn't have a __code__ attribute.
newcode = list(fcode.co_code) if PY3 else [ord(co) for co in fcode.co_code]
newconsts = list(fcode.co_consts)
names = fcode.co_names
codelen = len(newcode)
env = vars(builtins).copy()
if builtin_only:
stoplist = dict.fromkeys(stoplist)
stoplist.update(func.__globals__)
else:
env.update(func.__globals__)
# First pass converts global lookups into constants
changed = False
i = 0
while i < codelen:
opcode = newcode[i]
if opcode in (EXTENDED_ARG, STORE_GLOBAL):
return func # for simplicity, only optimize common cases
if opcode == LOAD_GLOBAL:
oparg = newcode[i + 1] + (newcode[i + 2] << 8)
name = fcode.co_names[oparg]
if name in env and name not in stoplist:
value = env[name]
for pos, val in enumerate(newconsts):
if val is value:
break
else:
pos = len(newconsts)
newconsts.append(value)
newcode[i] = LOAD_CONST
newcode[i + 1] = pos & 0xFF
newcode[i + 2] = pos >> 8
changed = True
if verbose is not None:
verbose("{0} --> {1}".format(name, value))
i += 1
if opcode >= HAVE_ARGUMENT:
i += 2
# Second pass folds tuples of constants and constant attribute lookups
i = 0
while i < codelen:
newtuple = []
while newcode[i] == LOAD_CONST:
oparg = newcode[i + 1] + (newcode[i + 2] << 8)
newtuple.append(newconsts[oparg])
i += 3
opcode = newcode[i]
if not newtuple:
i += 1
if opcode >= HAVE_ARGUMENT:
i += 2
continue
if opcode == LOAD_ATTR:
obj = newtuple[-1]
oparg = newcode[i + 1] + (newcode[i + 2] << 8)
name = names[oparg]
try:
value = getattr(obj, name)
except AttributeError:
continue
deletions = 1
elif opcode == BUILD_TUPLE:
oparg = newcode[i + 1] + (newcode[i + 2] << 8)
if oparg != len(newtuple):
continue
deletions = len(newtuple)
value = tuple(newtuple)
else:
continue
reljump = deletions * 3
newcode[i - reljump] = JUMP_FORWARD
newcode[i - reljump + 1] = (reljump - 3) & 0xFF
newcode[i - reljump + 2] = (reljump - 3) >> 8
nclen = len(newconsts)
newconsts.append(value)
newcode[i] = LOAD_CONST
newcode[i + 1] = nclen & 0xFF
newcode[i + 2] = nclen >> 8
i += 3
changed = True
if verbose is not None:
verbose("new folded constant:{0}".format(value))
if changed:
codeobj = getcodeobj(newconsts, newcode, fcode, fcode)
result = type(func)(
codeobj,
func.__globals__, func.__name__, func.__defaults__, func.__closure__
)
# set func attributes to result
for prop in WRAPPER_ASSIGNMENTS:
try:
attr = getattr(func, prop)
except AttributeError:
pass
else:
setattr(result, prop, attr)
return result
[docs]def getcodeobj(consts, intcode, newcodeobj, oldcodeobj):
"""Get code object from decompiled code.
:param list consts: constants to add in the result.
:param list intcode: list of byte code to use.
:param newcodeobj: new code object with empty body.
:param oldcodeobj: old code object.
:return: new code object to produce."""
# get code string
if PY3:
codestr = bytes(intcode)
else:
codestr = reduce(lambda x, y: x + y, (chr(b) for b in intcode))
# get vargs
vargs = [
newcodeobj.co_argcount, newcodeobj.co_nlocals, newcodeobj.co_stacksize,
newcodeobj.co_flags, codestr, tuple(consts), newcodeobj.co_names,
newcodeobj.co_varnames, newcodeobj.co_filename, newcodeobj.co_name,
newcodeobj.co_firstlineno, newcodeobj.co_lnotab,
oldcodeobj.co_freevars, newcodeobj.co_cellvars
]
if PY3:
vargs.insert(1, newcodeobj.co_kwonlyargcount)
# instanciate a new newcodeobj object
result = type(newcodeobj)(*vargs)
return result
_make_constants = _make_constants(_make_constants) # optimize thyself!
[docs]def bind_all(morc, builtin_only=False, stoplist=None, verbose=None):
"""Recursively apply constant binding to functions in a module or class.
Use as the last line of the module (after everything is defined, but
before test code). In modules that need modifiable globals, set
builtin_only to True.
:param morc: module or class to transform.
:param bool builtin_only: only transform builtin objects.
:param list stoplist: attribute names to not transform.
:param function verbose: logger function which takes in parameter a message
"""
if stoplist is None:
stoplist = []
def _bind_all(morc, builtin_only=False, stoplist=None, verbose=False):
"""Internal bind all decorator function.
"""
if stoplist is None:
stoplist = []
if isinstance(morc, (ModuleType, type)):
for k, val in list(vars(morc).items()):
if isinstance(val, FunctionType):
newv = _make_constants(
val, builtin_only, stoplist, verbose
)
setattr(morc, k, newv)
elif isinstance(val, type):
_bind_all(val, builtin_only, stoplist, verbose)
if isinstance(morc, dict): # allow: bind_all(globals())
for k, val in list(morc.items()):
if isinstance(val, FunctionType):
newv = _make_constants(val, builtin_only, stoplist, verbose)
morc[k] = newv
elif isinstance(val, type):
_bind_all(val, builtin_only, stoplist, verbose)
else:
_bind_all(morc, builtin_only, stoplist, verbose)
@_make_constants
[docs]def make_constants(builtin_only=False, stoplist=None, verbose=None):
"""Return a decorator for optimizing global references.
Replaces global references with their currently defined values.
If not defined, the dynamic (runtime) global lookup is left undisturbed.
If builtin_only is True, then only builtins are optimized.
Variable names in the stoplist are also left undisturbed.
Also, folds constant attr lookups and tuples of constants.
If verbose is True, prints each substitution as is occurs.
:param bool builtin_only: only transform builtin objects.
:param list stoplist: attribute names to not transform.
:param function verbose: logger function which takes in parameter a message
"""
if stoplist is None:
stoplist = []
if isinstance(builtin_only, type(make_constants)):
raise ValueError("The bind_constants decorator must have arguments.")
return lambda func: _make_constants(func, builtin_only, stoplist, verbose)