# MIT License
#
# Copyright The SCons Foundation
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be included
# in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
# KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
# WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
"""Various SCons utility functions."""
import copy
import hashlib
import os
import pprint
import re
import sys
from collections import UserDict, UserList, UserString, OrderedDict
from collections.abc import MappingView
from contextlib import suppress
from types import MethodType, FunctionType
from typing import Optional, Union
# Note: Util module cannot import other bits of SCons globally without getting
# into import loops. Both the below modules import SCons.Util early on.
# --> SCons.Warnings
# --> SCons.Errors
# Thus the local imports, which are annotated for pylint to show we mean it.
PYPY = hasattr(sys, 'pypy_translation_info')
# this string will be hashed if a Node refers to a file that doesn't exist
# in order to distinguish from a file that exists but is empty.
NOFILE = "SCONS_MAGIC_MISSING_FILE_STRING"
# unused?
[docs]def dictify(keys, values, result=None) -> dict:
if result is None:
result = {}
result.update(dict(zip(keys, values)))
return result
_ALTSEP = os.altsep
if _ALTSEP is None and sys.platform == 'win32':
# My ActivePython 2.0.1 doesn't set os.altsep! What gives?
_ALTSEP = '/'
if _ALTSEP:
def rightmost_separator(path, sep):
return max(path.rfind(sep), path.rfind(_ALTSEP))
else:
[docs] def rightmost_separator(path, sep):
return path.rfind(sep)
# First two from the Python Cookbook, just for completeness.
# (Yeah, yeah, YAGNI...)
[docs]def containsAny(s, pat) -> bool:
"""Check whether string `s` contains ANY of the items in `pat`."""
for c in pat:
if c in s:
return True
return False
[docs]def containsAll(s, pat) -> bool:
"""Check whether string `s` contains ALL of the items in `pat`."""
for c in pat:
if c not in s:
return False
return True
[docs]def containsOnly(s, pat) -> bool:
"""Check whether string `s` contains ONLY items in `pat`."""
for c in s:
if c not in pat:
return False
return True
# TODO: Verify this method is STILL faster than os.path.splitext
[docs]def splitext(path) -> tuple:
"""Split `path` into a (root, ext) pair.
Same as :mod:`os.path.splitext` but faster.
"""
sep = rightmost_separator(path, os.sep)
dot = path.rfind('.')
# An ext is only real if it has at least one non-digit char
if dot > sep and not containsOnly(path[dot:], "0123456789."):
return path[:dot], path[dot:]
return path, ""
[docs]def updrive(path) -> str:
"""Make the drive letter (if any) upper case.
This is useful because Windows is inconsistent on the case
of the drive letter, which can cause inconsistencies when
calculating command signatures.
"""
drive, rest = os.path.splitdrive(path)
if drive:
path = drive.upper() + rest
return path
[docs]class NodeList(UserList):
"""A list of Nodes with special attribute retrieval.
Unlike an ordinary list, access to a member's attribute returns a
`NodeList` containing the same attribute for each member. Although
this can hold any object, it is intended for use when processing
Nodes, where fetching an attribute of each member is very commone,
for example getting the content signature of each node. The term
"attribute" here includes the string representation.
Example:
>>> someList = NodeList([' foo ', ' bar '])
>>> someList.strip()
['foo', 'bar']
"""
def __bool__(self):
return bool(self.data)
def __str__(self):
return ' '.join(map(str, self.data))
def __iter__(self):
return iter(self.data)
def __call__(self, *args, **kwargs) -> 'NodeList':
result = [x(*args, **kwargs) for x in self.data]
return self.__class__(result)
def __getattr__(self, name) -> 'NodeList':
"""Returns a NodeList of `name` from each member."""
result = [getattr(x, name) for x in self.data]
return self.__class__(result)
def __getitem__(self, index):
"""Returns one item, forces a `NodeList` if `index` is a slice."""
# TODO: annotate return how? Union[] - don't know type of single item
if isinstance(index, slice):
return self.__class__(self.data[index])
return self.data[index]
_get_env_var = re.compile(r'^\$([_a-zA-Z]\w*|{[_a-zA-Z]\w*})$')
[docs]def get_environment_var(varstr) -> Optional[str]:
"""Return undecorated construction variable string.
Determine if `varstr` looks like a reference
to a single environment variable, like `"$FOO"` or `"${FOO}"`.
If so, return that variable with no decorations, like `"FOO"`.
If not, return `None`.
"""
mo = _get_env_var.match(to_String(varstr))
if mo:
var = mo.group(1)
if var[0] == '{':
return var[1:-1]
return var
return None
[docs]class DisplayEngine:
"""A callable class used to display SCons messages."""
print_it = True
def __call__(self, text, append_newline=1):
if not self.print_it:
return
if append_newline:
text = text + '\n'
try:
sys.stdout.write(str(text))
except IOError:
# Stdout might be connected to a pipe that has been closed
# by now. The most likely reason for the pipe being closed
# is that the user has press ctrl-c. It this is the case,
# then SCons is currently shutdown. We therefore ignore
# IOError's here so that SCons can continue and shutdown
# properly so that the .sconsign is correctly written
# before SCons exits.
pass
[docs] def set_mode(self, mode):
self.print_it = mode
# TODO: W0102: Dangerous default value [] as argument (dangerous-default-value)
[docs]def render_tree(root, child_func, prune=0, margin=[0], visited=None):
"""Render a tree of nodes into an ASCII tree view.
Args:
root: the root node of the tree
child_func: the function called to get the children of a node
prune: don't visit the same node twice
margin: the format of the left margin to use for children of `root`.
1 results in a pipe, and 0 results in no pipe.
visited: a dictionary of visited nodes in the current branch if
`prune` is 0, or in the whole tree if `prune` is 1.
"""
rname = str(root)
# Initialize 'visited' dict, if required
if visited is None:
visited = {}
children = child_func(root)
retval = ""
for pipe in margin[:-1]:
if pipe:
retval = retval + "| "
else:
retval = retval + " "
if rname in visited:
return retval + "+-[" + rname + "]\n"
retval = retval + "+-" + rname + "\n"
if not prune:
visited = copy.copy(visited)
visited[rname] = True
for i, child in enumerate(children):
margin.append(i < len(children)-1)
retval = retval + render_tree(child, child_func, prune, margin, visited)
margin.pop()
return retval
[docs]def IDX(n) -> bool:
"""Generate in index into strings from the tree legends.
These are always a choice between two, so bool works fine.
"""
return bool(n)
# unicode line drawing chars:
BOX_HORIZ = chr(0x2500) # '─'
BOX_VERT = chr(0x2502) # '│'
BOX_UP_RIGHT = chr(0x2514) # '└'
BOX_DOWN_RIGHT = chr(0x250c) # '┌'
BOX_DOWN_LEFT = chr(0x2510) # '┐'
BOX_UP_LEFT = chr(0x2518) # '┘'
BOX_VERT_RIGHT = chr(0x251c) # '├'
BOX_HORIZ_DOWN = chr(0x252c) # '┬'
# TODO: W0102: Dangerous default value [] as argument (dangerous-default-value)
[docs]def print_tree(
root,
child_func,
prune=0,
showtags=False,
margin=[0],
visited=None,
lastChild=False,
singleLineDraw=False,
):
"""Print a tree of nodes.
This is like func:`render_tree`, except it prints lines directly instead
of creating a string representation in memory, so that huge trees can
be handled.
Args:
root: the root node of the tree
child_func: the function called to get the children of a node
prune: don't visit the same node twice
showtags: print status information to the left of each node line
margin: the format of the left margin to use for children of `root`.
1 results in a pipe, and 0 results in no pipe.
visited: a dictionary of visited nodes in the current branch if
prune` is 0, or in the whole tree if `prune` is 1.
singleLineDraw: use line-drawing characters rather than ASCII.
"""
rname = str(root)
# Initialize 'visited' dict, if required
if visited is None:
visited = {}
if showtags:
if showtags == 2:
legend = (' E = exists\n' +
' R = exists in repository only\n' +
' b = implicit builder\n' +
' B = explicit builder\n' +
' S = side effect\n' +
' P = precious\n' +
' A = always build\n' +
' C = current\n' +
' N = no clean\n' +
' H = no cache\n' +
'\n')
sys.stdout.write(legend)
tags = [
'[',
' E'[IDX(root.exists())],
' R'[IDX(root.rexists() and not root.exists())],
' BbB'[
[0, 1][IDX(root.has_explicit_builder())] +
[0, 2][IDX(root.has_builder())]
],
' S'[IDX(root.side_effect)],
' P'[IDX(root.precious)],
' A'[IDX(root.always_build)],
' C'[IDX(root.is_up_to_date())],
' N'[IDX(root.noclean)],
' H'[IDX(root.nocache)],
']'
]
else:
tags = []
def MMM(m):
if singleLineDraw:
return [" ", BOX_VERT + " "][m]
return [" ", "| "][m]
margins = list(map(MMM, margin[:-1]))
children = child_func(root)
cross = "+-"
if singleLineDraw:
cross = BOX_VERT_RIGHT + BOX_HORIZ # sign used to point to the leaf.
# check if this is the last leaf of the branch
if lastChild:
#if this if the last leaf, then terminate:
cross = BOX_UP_RIGHT + BOX_HORIZ # sign for the last leaf
# if this branch has children then split it
if children:
# if it's a leaf:
if prune and rname in visited and children:
cross += BOX_HORIZ
else:
cross += BOX_HORIZ_DOWN
if prune and rname in visited and children:
sys.stdout.write(''.join(tags + margins + [cross,'[', rname, ']']) + '\n')
return
sys.stdout.write(''.join(tags + margins + [cross, rname]) + '\n')
visited[rname] = 1
# if this item has children:
if children:
margin.append(1) # Initialize margin with 1 for vertical bar.
idx = IDX(showtags)
_child = 0 # Initialize this for the first child.
for C in children[:-1]:
_child = _child + 1 # number the children
print_tree(
C,
child_func,
prune,
idx,
margin,
visited,
(len(children) - _child) <= 0,
singleLineDraw,
)
# margins are with space (index 0) because we arrived to the last child.
margin[-1] = 0
# for this call child and nr of children needs to be set 0, to signal the second phase.
print_tree(children[-1], child_func, prune, idx, margin, visited, True, singleLineDraw)
margin.pop() # destroy the last margin added
# Functions for deciding if things are like various types, mainly to
# handle UserDict, UserList and UserString like their underlying types.
#
# Yes, all of this manual testing breaks polymorphism, and the real
# Pythonic way to do all of this would be to just try it and handle the
# exception, but handling the exception when it's not the right type is
# often too slow.
# We are using the following trick to speed up these
# functions. Default arguments are used to take a snapshot of
# the global functions and constants used by these functions. This
# transforms accesses to global variable into local variables
# accesses (i.e. LOAD_FAST instead of LOAD_GLOBAL).
# Since checkers dislike this, it's now annotated for pylint to flag
# (mostly for other readers of this code) we're doing this intentionally.
# TODO: PY3 check these are still valid choices for all of these funcs.
DictTypes = (dict, UserDict)
ListTypes = (list, UserList)
# Handle getting dictionary views.
SequenceTypes = (list, tuple, UserList, MappingView)
# Note that profiling data shows a speed-up when comparing
# explicitly with str instead of simply comparing
# with basestring. (at least on Python 2.5.1)
# TODO: PY3 check this benchmarking is still correct.
StringTypes = (str, UserString)
# Empirically, it is faster to check explicitly for str than for basestring.
BaseStringTypes = str
[docs]def is_Dict( # pylint: disable=redefined-outer-name,redefined-builtin
obj, isinstance=isinstance, DictTypes=DictTypes
) -> bool:
return isinstance(obj, DictTypes)
[docs]def is_List( # pylint: disable=redefined-outer-name,redefined-builtin
obj, isinstance=isinstance, ListTypes=ListTypes
) -> bool:
return isinstance(obj, ListTypes)
[docs]def is_Sequence( # pylint: disable=redefined-outer-name,redefined-builtin
obj, isinstance=isinstance, SequenceTypes=SequenceTypes
) -> bool:
return isinstance(obj, SequenceTypes)
[docs]def is_Tuple( # pylint: disable=redefined-builtin
obj, isinstance=isinstance, tuple=tuple
) -> bool:
return isinstance(obj, tuple)
[docs]def is_String( # pylint: disable=redefined-outer-name,redefined-builtin
obj, isinstance=isinstance, StringTypes=StringTypes
) -> bool:
return isinstance(obj, StringTypes)
[docs]def is_Scalar( # pylint: disable=redefined-outer-name,redefined-builtin
obj, isinstance=isinstance, StringTypes=StringTypes, SequenceTypes=SequenceTypes
) -> bool:
# Profiling shows that there is an impressive speed-up of 2x
# when explicitly checking for strings instead of just not
# sequence when the argument (i.e. obj) is already a string.
# But, if obj is a not string then it is twice as fast to
# check only for 'not sequence'. The following code therefore
# assumes that the obj argument is a string most of the time.
return isinstance(obj, StringTypes) or not isinstance(obj, SequenceTypes)
[docs]def do_flatten(
sequence,
result,
isinstance=isinstance,
StringTypes=StringTypes,
SequenceTypes=SequenceTypes,
): # pylint: disable=redefined-outer-name,redefined-builtin
for item in sequence:
if isinstance(item, StringTypes) or not isinstance(item, SequenceTypes):
result.append(item)
else:
do_flatten(item, result)
[docs]def flatten( # pylint: disable=redefined-outer-name,redefined-builtin
obj,
isinstance=isinstance,
StringTypes=StringTypes,
SequenceTypes=SequenceTypes,
do_flatten=do_flatten,
) -> list:
"""Flatten a sequence to a non-nested list.
Converts either a single scalar or a nested sequence to a non-nested list.
Note that :func:`flatten` considers strings
to be scalars instead of sequences like pure Python would.
"""
if isinstance(obj, StringTypes) or not isinstance(obj, SequenceTypes):
return [obj]
result = []
for item in obj:
if isinstance(item, StringTypes) or not isinstance(item, SequenceTypes):
result.append(item)
else:
do_flatten(item, result)
return result
[docs]def flatten_sequence( # pylint: disable=redefined-outer-name,redefined-builtin
sequence,
isinstance=isinstance,
StringTypes=StringTypes,
SequenceTypes=SequenceTypes,
do_flatten=do_flatten,
) -> list:
"""Flatten a sequence to a non-nested list.
Same as :func:`flatten`, but it does not handle the single scalar case.
This is slightly more efficient when one knows that the sequence
to flatten can not be a scalar.
"""
result = []
for item in sequence:
if isinstance(item, StringTypes) or not isinstance(item, SequenceTypes):
result.append(item)
else:
do_flatten(item, result)
return result
# Generic convert-to-string functions. The wrapper
# to_String_for_signature() will use a for_signature() method if the
# specified object has one.
[docs]def to_String( # pylint: disable=redefined-outer-name,redefined-builtin
obj,
isinstance=isinstance,
str=str,
UserString=UserString,
BaseStringTypes=BaseStringTypes,
) -> str:
"""Return a string version of obj."""
if isinstance(obj, BaseStringTypes):
# Early out when already a string!
return obj
if isinstance(obj, UserString):
# obj.data can only be a regular string. Please see the UserString initializer.
return obj.data
return str(obj)
[docs]def to_String_for_subst( # pylint: disable=redefined-outer-name,redefined-builtin
obj,
isinstance=isinstance,
str=str,
BaseStringTypes=BaseStringTypes,
SequenceTypes=SequenceTypes,
UserString=UserString,
) -> str:
"""Return a string version of obj for subst usage."""
# Note that the test cases are sorted by order of probability.
if isinstance(obj, BaseStringTypes):
return obj
if isinstance(obj, SequenceTypes):
return ' '.join([to_String_for_subst(e) for e in obj])
if isinstance(obj, UserString):
# obj.data can only a regular string. Please see the UserString initializer.
return obj.data
return str(obj)
[docs]def to_String_for_signature( # pylint: disable=redefined-outer-name,redefined-builtin
obj, to_String_for_subst=to_String_for_subst, AttributeError=AttributeError
) -> str:
"""Return a string version of obj for signature usage.
Like :func:`to_String_for_subst` but has special handling for
scons objects that have a :meth:`for_signature` method, and for dicts.
"""
try:
f = obj.for_signature
except AttributeError:
if isinstance(obj, dict):
# pprint will output dictionary in key sorted order
# with py3.5 the order was randomized. In general depending on dictionary order
# which was undefined until py3.6 (where it's by insertion order) was not wise.
# TODO: Change code when floor is raised to PY36
return pprint.pformat(obj, width=1000000)
return to_String_for_subst(obj)
else:
return f()
# The SCons "semi-deep" copy.
#
# This makes separate copies of lists (including UserList objects)
# dictionaries (including UserDict objects) and tuples, but just copies
# references to anything else it finds.
#
# A special case is any object that has a __semi_deepcopy__() method,
# which we invoke to create the copy. Currently only used by
# BuilderDict to actually prevent the copy operation (as invalid on that object).
#
# The dispatch table approach used here is a direct rip-off from the
# normal Python copy module.
[docs]def semi_deepcopy_dict(obj, exclude=None) -> dict:
if exclude is None:
exclude = []
return {k: semi_deepcopy(v) for k, v in obj.items() if k not in exclude}
[docs]def _semi_deepcopy_list(obj) -> list:
return [semi_deepcopy(item) for item in obj]
[docs]def _semi_deepcopy_tuple(obj) -> tuple:
return tuple(map(semi_deepcopy, obj))
_semi_deepcopy_dispatch = {
dict: semi_deepcopy_dict,
list: _semi_deepcopy_list,
tuple: _semi_deepcopy_tuple,
}
[docs]def semi_deepcopy(obj):
copier = _semi_deepcopy_dispatch.get(type(obj))
if copier:
return copier(obj)
if hasattr(obj, '__semi_deepcopy__') and callable(obj.__semi_deepcopy__):
return obj.__semi_deepcopy__()
if isinstance(obj, UserDict):
return obj.__class__(semi_deepcopy_dict(obj))
if isinstance(obj, UserList):
return obj.__class__(_semi_deepcopy_list(obj))
return obj
[docs]class Proxy:
"""A simple generic Proxy class, forwarding all calls to subject.
This means you can take an object, let's call it `'obj_a`,
and wrap it in this Proxy class, with a statement like this::
proxy_obj = Proxy(obj_a)
Then, if in the future, you do something like this::
x = proxy_obj.var1
since the :class:`Proxy` class does not have a :attr:`var1` attribute
(but presumably `objA` does), the request actually is equivalent to saying::
x = obj_a.var1
Inherit from this class to create a Proxy.
With Python 3.5+ this does *not* work transparently
for :class:`Proxy` subclasses that use special .__*__() method names,
because those names are now bound to the class, not the individual
instances. You now need to know in advance which special method names you
want to pass on to the underlying Proxy object, and specifically delegate
their calls like this::
class Foo(Proxy):
__str__ = Delegate('__str__')
"""
def __init__(self, subject):
"""Wrap an object as a Proxy object"""
self._subject = subject
def __getattr__(self, name):
"""Retrieve an attribute from the wrapped object.
Raises:
AttributeError: if attribute `name` doesn't exist.
"""
return getattr(self._subject, name)
[docs] def get(self):
"""Retrieve the entire wrapped object"""
return self._subject
def __eq__(self, other):
if issubclass(other.__class__, self._subject.__class__):
return self._subject == other
return self.__dict__ == other.__dict__
[docs]class Delegate:
"""A Python Descriptor class that delegates attribute fetches
to an underlying wrapped subject of a Proxy. Typical use::
class Foo(Proxy):
__str__ = Delegate('__str__')
"""
def __init__(self, attribute):
self.attribute = attribute
def __get__(self, obj, cls):
if isinstance(obj, cls):
return getattr(obj._subject, self.attribute)
return self
[docs]class MethodWrapper:
"""A generic Wrapper class that associates a method with an object.
As part of creating this MethodWrapper object an attribute with the
specified name (by default, the name of the supplied method) is added
to the underlying object. When that new "method" is called, our
:meth:`__call__` method adds the object as the first argument, simulating
the Python behavior of supplying "self" on method calls.
We hang on to the name by which the method was added to the underlying
base class so that we can provide a method to "clone" ourselves onto
a new underlying object being copied (without which we wouldn't need
to save that info).
"""
def __init__(self, obj, method, name=None):
if name is None:
name = method.__name__
self.object = obj
self.method = method
self.name = name
setattr(self.object, name, self)
def __call__(self, *args, **kwargs):
nargs = (self.object,) + args
return self.method(*nargs, **kwargs)
[docs] def clone(self, new_object):
"""
Returns an object that re-binds the underlying "method" to
the specified new object.
"""
return self.__class__(new_object, self.method, self.name)
# attempt to load the windows registry module:
can_read_reg = False
try:
import winreg
can_read_reg = True
hkey_mod = winreg
except ImportError:
[docs] class _NoError(Exception):
pass
RegError = _NoError
if can_read_reg:
HKEY_CLASSES_ROOT = hkey_mod.HKEY_CLASSES_ROOT
HKEY_LOCAL_MACHINE = hkey_mod.HKEY_LOCAL_MACHINE
HKEY_CURRENT_USER = hkey_mod.HKEY_CURRENT_USER
HKEY_USERS = hkey_mod.HKEY_USERS
RegOpenKeyEx = winreg.OpenKeyEx
RegEnumKey = winreg.EnumKey
RegEnumValue = winreg.EnumValue
RegQueryValueEx = winreg.QueryValueEx
RegError = winreg.error
def RegGetValue(root, key):
r"""Returns a registry value without having to open the key first.
Only available on Windows platforms with a version of Python that
can read the registry.
Returns the same thing as :func:`RegQueryValueEx`, except you just
specify the entire path to the value, and don't have to bother
opening the key first. So, instead of::
k = SCons.Util.RegOpenKeyEx(SCons.Util.HKEY_LOCAL_MACHINE,
r'SOFTWARE\Microsoft\Windows\CurrentVersion')
out = SCons.Util.RegQueryValueEx(k, 'ProgramFilesDir')
You can write::
out = SCons.Util.RegGetValue(SCons.Util.HKEY_LOCAL_MACHINE,
r'SOFTWARE\Microsoft\Windows\CurrentVersion\ProgramFilesDir')
"""
# I would use os.path.split here, but it's not a filesystem
# path...
p = key.rfind('\\') + 1
keyp = key[: p - 1] # -1 to omit trailing slash
val = key[p:]
k = RegOpenKeyEx(root, keyp)
return RegQueryValueEx(k, val)
else:
HKEY_CLASSES_ROOT = None
HKEY_LOCAL_MACHINE = None
HKEY_CURRENT_USER = None
HKEY_USERS = None
[docs] def RegGetValue(root, key):
raise OSError
[docs] def RegOpenKeyEx(root, key):
raise OSError
if sys.platform == 'win32':
def WhereIs(file, path=None, pathext=None, reject=None) -> Optional[str]:
if path is None:
try:
path = os.environ['PATH']
except KeyError:
return None
if is_String(path):
path = path.split(os.pathsep)
if pathext is None:
try:
pathext = os.environ['PATHEXT']
except KeyError:
pathext = '.COM;.EXE;.BAT;.CMD'
if is_String(pathext):
pathext = pathext.split(os.pathsep)
for ext in pathext:
if ext.lower() == file[-len(ext):].lower():
pathext = ['']
break
if reject is None:
reject = []
if not is_List(reject) and not is_Tuple(reject):
reject = [reject]
for p in path:
f = os.path.join(p, file)
for ext in pathext:
fext = f + ext
if os.path.isfile(fext):
try:
reject.index(fext)
except ValueError:
return os.path.normpath(fext)
continue
return None
elif os.name == 'os2':
def WhereIs(file, path=None, pathext=None, reject=None) -> Optional[str]:
if path is None:
try:
path = os.environ['PATH']
except KeyError:
return None
if is_String(path):
path = path.split(os.pathsep)
if pathext is None:
pathext = ['.exe', '.cmd']
for ext in pathext:
if ext.lower() == file[-len(ext):].lower():
pathext = ['']
break
if reject is None:
reject = []
if not is_List(reject) and not is_Tuple(reject):
reject = [reject]
for p in path:
f = os.path.join(p, file)
for ext in pathext:
fext = f + ext
if os.path.isfile(fext):
try:
reject.index(fext)
except ValueError:
return os.path.normpath(fext)
continue
return None
else:
[docs] def WhereIs(file, path=None, pathext=None, reject=None) -> Optional[str]:
import stat # pylint: disable=import-outside-toplevel
if path is None:
try:
path = os.environ['PATH']
except KeyError:
return None
if is_String(path):
path = path.split(os.pathsep)
if reject is None:
reject = []
if not is_List(reject) and not is_Tuple(reject):
reject = [reject]
for p in path:
f = os.path.join(p, file)
if os.path.isfile(f):
try:
st = os.stat(f)
except OSError:
# os.stat() raises OSError, not IOError if the file
# doesn't exist, so in this case we let IOError get
# raised so as to not mask possibly serious disk or
# network issues.
continue
if stat.S_IMODE(st[stat.ST_MODE]) & 0o111:
try:
reject.index(f)
except ValueError:
return os.path.normpath(f)
continue
return None
WhereIs.__doc__ = """\
Return the path to an executable that matches `file`.
Searches the given `path` for `file`, respecting any filename
extensions `pathext` (on the Windows platform only), and
returns the full path to the matching command. If no
command is found, return ``None``.
If `path` is not specified, :attr:`os.environ[PATH]` is used.
If `pathext` is not specified, :attr:`os.environ[PATHEXT]`
is used. Will not select any path name or names in the optional
`reject` list.
"""
[docs]def PrependPath(
oldpath, newpath, sep=os.pathsep, delete_existing=True, canonicalize=None
) -> Union[list, str]:
"""Prepends `newpath` path elements to `oldpath`.
Will only add any particular path once (leaving the first one it
encounters and ignoring the rest, to preserve path order), and will
:mod:`os.path.normpath` and :mod:`os.path.normcase` all paths to help
assure this. This can also handle the case where `oldpath`
is a list instead of a string, in which case a list will be returned
instead of a string. For example:
>>> p = PrependPath("/foo/bar:/foo", "/biz/boom:/foo")
>>> print(p)
/biz/boom:/foo:/foo/bar
If `delete_existing` is ``False``, then adding a path that exists will
not move it to the beginning; it will stay where it is in the list.
>>> p = PrependPath("/foo/bar:/foo", "/biz/boom:/foo", delete_existing=False)
>>> print(p)
/biz/boom:/foo/bar:/foo
If `canonicalize` is not ``None``, it is applied to each element of
`newpath` before use.
"""
orig = oldpath
is_list = True
paths = orig
if not is_List(orig) and not is_Tuple(orig):
paths = paths.split(sep)
is_list = False
if is_String(newpath):
newpaths = newpath.split(sep)
elif not is_List(newpath) and not is_Tuple(newpath):
newpaths = [ newpath ] # might be a Dir
else:
newpaths = newpath
if canonicalize:
newpaths=list(map(canonicalize, newpaths))
if not delete_existing:
# First uniquify the old paths, making sure to
# preserve the first instance (in Unix/Linux,
# the first one wins), and remembering them in normpaths.
# Then insert the new paths at the head of the list
# if they're not already in the normpaths list.
result = []
normpaths = []
for path in paths:
if not path:
continue
normpath = os.path.normpath(os.path.normcase(path))
if normpath not in normpaths:
result.append(path)
normpaths.append(normpath)
newpaths.reverse() # since we're inserting at the head
for path in newpaths:
if not path:
continue
normpath = os.path.normpath(os.path.normcase(path))
if normpath not in normpaths:
result.insert(0, path)
normpaths.append(normpath)
paths = result
else:
newpaths = newpaths + paths # prepend new paths
normpaths = []
paths = []
# now we add them only if they are unique
for path in newpaths:
normpath = os.path.normpath(os.path.normcase(path))
if path and normpath not in normpaths:
paths.append(path)
normpaths.append(normpath)
if is_list:
return paths
return sep.join(paths)
[docs]def AppendPath(
oldpath, newpath, sep=os.pathsep, delete_existing=True, canonicalize=None
) -> Union[list, str]:
"""Appends `newpath` path elements to `oldpath`.
Will only add any particular path once (leaving the last one it
encounters and ignoring the rest, to preserve path order), and will
:mod:`os.path.normpath` and :mod:`os.path.normcase` all paths to help
assure this. This can also handle the case where `oldpath`
is a list instead of a string, in which case a list will be returned
instead of a string. For example:
>>> p = AppendPath("/foo/bar:/foo", "/biz/boom:/foo")
>>> print(p)
/foo/bar:/biz/boom:/foo
If `delete_existing` is ``False``, then adding a path that exists
will not move it to the end; it will stay where it is in the list.
>>> p = AppendPath("/foo/bar:/foo", "/biz/boom:/foo", delete_existing=False)
>>> print(p)
/foo/bar:/foo:/biz/boom
If `canonicalize` is not ``None``, it is applied to each element of
`newpath` before use.
"""
orig = oldpath
is_list = True
paths = orig
if not is_List(orig) and not is_Tuple(orig):
paths = paths.split(sep)
is_list = False
if is_String(newpath):
newpaths = newpath.split(sep)
elif not is_List(newpath) and not is_Tuple(newpath):
newpaths = [newpath] # might be a Dir
else:
newpaths = newpath
if canonicalize:
newpaths=list(map(canonicalize, newpaths))
if not delete_existing:
# add old paths to result, then
# add new paths if not already present
# (I thought about using a dict for normpaths for speed,
# but it's not clear hashing the strings would be faster
# than linear searching these typically short lists.)
result = []
normpaths = []
for path in paths:
if not path:
continue
result.append(path)
normpaths.append(os.path.normpath(os.path.normcase(path)))
for path in newpaths:
if not path:
continue
normpath = os.path.normpath(os.path.normcase(path))
if normpath not in normpaths:
result.append(path)
normpaths.append(normpath)
paths = result
else:
# start w/ new paths, add old ones if not present,
# then reverse.
newpaths = paths + newpaths # append new paths
newpaths.reverse()
normpaths = []
paths = []
# now we add them only if they are unique
for path in newpaths:
normpath = os.path.normpath(os.path.normcase(path))
if path and normpath not in normpaths:
paths.append(path)
normpaths.append(normpath)
paths.reverse()
if is_list:
return paths
return sep.join(paths)
[docs]def AddPathIfNotExists(env_dict, key, path, sep=os.pathsep):
"""Add a path element to a construction variable.
`key` is looked up in `env_dict`, and `path` is added to it if it
is not already present. `env_dict[key]` is assumed to be in the
format of a PATH variable: a list of paths separated by `sep` tokens.
Example:
>>> env = {'PATH': '/bin:/usr/bin:/usr/local/bin'}
>>> AddPathIfNotExists(env, 'PATH', '/opt/bin')
>>> print(env['PATH'])
/opt/bin:/bin:/usr/bin:/usr/local/bin
"""
try:
is_list = True
paths = env_dict[key]
if not is_List(env_dict[key]):
paths = paths.split(sep)
is_list = False
if os.path.normcase(path) not in list(map(os.path.normcase, paths)):
paths = [ path ] + paths
if is_list:
env_dict[key] = paths
else:
env_dict[key] = sep.join(paths)
except KeyError:
env_dict[key] = path
if sys.platform == 'cygwin':
import subprocess # pylint: disable=import-outside-toplevel
def get_native_path(path) -> str:
cp = subprocess.run(('cygpath', '-w', path), check=False, stdout=subprocess.PIPE)
return cp.stdout.decode().replace('\n', '')
else:
[docs] def get_native_path(path) -> str:
return path
get_native_path.__doc__ = """\
Transform an absolute path into a native path for the system.
In Cygwin, this converts from a Cygwin path to a Windows path,
without regard to whether `path` refers to an existing file
system object. For other platforms, `path` is unchanged.
"""
display = DisplayEngine()
[docs]def Split(arg) -> list:
"""Returns a list of file names or other objects.
If `arg` is a string, it will be split on strings of white-space
characters within the string. If `arg` is already a list, the list
will be returned untouched. If `arg` is any other type of object,
it will be returned as a list containing just the object.
>>> print(Split(" this is a string "))
['this', 'is', 'a', 'string']
>>> print(Split(["stringlist", " preserving ", " spaces "]))
['stringlist', ' preserving ', ' spaces ']
"""
if is_List(arg) or is_Tuple(arg):
return arg
if is_String(arg):
return arg.split()
return [arg]
[docs]class CLVar(UserList):
"""A container for command-line construction variables.
Forces the use of a list of strings intended as command-line
arguments. Like :class:`collections.UserList`, but the argument
passed to the initializter will be processed by the :func:`Split`
function, which includes special handling for string types: they
will be split into a list of words, not coereced directly to a list.
The same happens if a string is added to a :class:`CLVar`,
which allows doing the right thing with both
:func:`Append`/:func:`Prepend` methods,
as well as with pure Python addition, regardless of whether adding
a list or a string to a construction variable.
Side effect: spaces will be stripped from individual string
arguments. If you need spaces preserved, pass strings containing
spaces inside a list argument.
>>> u = UserList("--some --opts and args")
>>> print(len(u), repr(u))
22 ['-', '-', 's', 'o', 'm', 'e', ' ', '-', '-', 'o', 'p', 't', 's', ' ', 'a', 'n', 'd', ' ', 'a', 'r', 'g', 's']
>>> c = CLVar("--some --opts and args")
>>> print(len(c), repr(c))
4 ['--some', '--opts', 'and', 'args']
>>> c += " strips spaces "
>>> print(len(c), repr(c))
6 ['--some', '--opts', 'and', 'args', 'strips', 'spaces']
"""
def __init__(self, initlist=None):
super().__init__(Split(initlist if initlist is not None else []))
def __add__(self, other):
return super().__add__(CLVar(other))
def __radd__(self, other):
return super().__radd__(CLVar(other))
def __iadd__(self, other):
return super().__iadd__(CLVar(other))
def __str__(self):
return ' '.join(self.data)
[docs]class Selector(OrderedDict):
"""A callable ordered dictionary that maps file suffixes to
dictionary values. We preserve the order in which items are added
so that :func:`get_suffix` calls always return the first suffix added.
"""
def __call__(self, env, source, ext=None):
if ext is None:
try:
ext = source[0].get_suffix()
except IndexError:
ext = ""
try:
return self[ext]
except KeyError:
# Try to perform Environment substitution on the keys of
# the dictionary before giving up.
s_dict = {}
for (k,v) in self.items():
if k is not None:
s_k = env.subst(k)
if s_k in s_dict:
# We only raise an error when variables point
# to the same suffix. If one suffix is literal
# and a variable suffix contains this literal,
# the literal wins and we don't raise an error.
raise KeyError(s_dict[s_k][0], k, s_k)
s_dict[s_k] = (k,v)
try:
return s_dict[ext][1]
except KeyError:
try:
return self[None]
except KeyError:
return None
if sys.platform == 'cygwin':
# On Cygwin, os.path.normcase() lies, so just report back the
# fact that the underlying Windows OS is case-insensitive.
def case_sensitive_suffixes(s1, s2) -> bool: # pylint: disable=unused-argument
return False
else:
[docs] def case_sensitive_suffixes(s1, s2) -> bool:
return os.path.normcase(s1) != os.path.normcase(s2)
[docs]def adjustixes(fname, pre, suf, ensure_suffix=False) -> str:
"""Adjust filename prefixes and suffixes as needed.
Add `prefix` to `fname` if specified.
Add `suffix` to `fname` if specified and if `ensure_suffix` is ``True``
"""
if pre:
path, fn = os.path.split(os.path.normpath(fname))
# Handle the odd case where the filename = the prefix.
# In that case, we still want to add the prefix to the file
if not fn.startswith(pre) or fn == pre:
fname = os.path.join(path, pre + fn)
# Only append a suffix if the suffix we're going to add isn't already
# there, and if either we've been asked to ensure the specific suffix
# is present or there's no suffix on it at all.
# Also handle the odd case where the filename = the suffix.
# in that case we still want to append the suffix
if suf and not fname.endswith(suf) and \
(ensure_suffix or not splitext(fname)[1]):
fname = fname + suf
return fname
# From Tim Peters,
# https://code.activestate.com/recipes/52560
# ASPN: Python Cookbook: Remove duplicates from a sequence
# (Also in the printed Python Cookbook.)
# Updated. This algorithm is used by some scanners and tools.
[docs]def unique(seq):
"""Return a list of the elements in seq without duplicates, ignoring order.
>>> mylist = unique([1, 2, 3, 1, 2, 3])
>>> print(sorted(mylist))
[1, 2, 3]
>>> mylist = unique("abcabc")
>>> print(sorted(mylist))
['a', 'b', 'c']
>>> mylist = unique(([1, 2], [2, 3], [1, 2]))
>>> print(sorted(mylist))
[[1, 2], [2, 3]]
For best speed, all sequence elements should be hashable. Then
unique() will usually work in linear time.
If not possible, the sequence elements should enjoy a total
ordering, and if list(s).sort() doesn't raise TypeError it's
assumed that they do enjoy a total ordering. Then unique() will
usually work in O(N*log2(N)) time.
If that's not possible either, the sequence elements must support
equality-testing. Then unique() will usually work in quadratic time.
"""
if not seq:
return []
# Try using a dict first, as that's the fastest and will usually
# work. If it doesn't work, it will usually fail quickly, so it
# usually doesn't cost much to *try* it. It requires that all the
# sequence elements be hashable, and support equality comparison.
# TODO: should be even faster: return(list(set(seq)))
with suppress(TypeError):
return list(dict.fromkeys(seq))
# We couldn't hash all the elements (got a TypeError).
# Next fastest is to sort, which brings the equal elements together;
# then duplicates are easy to weed out in a single pass.
# NOTE: Python's list.sort() was designed to be efficient in the
# presence of many duplicate elements. This isn't true of all
# sort functions in all languages or libraries, so this approach
# is more effective in Python than it may be elsewhere.
n = len(seq)
try:
t = sorted(seq)
except TypeError:
pass # move on to the next method
else:
last = t[0]
lasti = i = 1
while i < n:
if t[i] != last:
t[lasti] = last = t[i]
lasti = lasti + 1
i = i + 1
return t[:lasti]
# Brute force is all that's left.
u = []
for x in seq:
if x not in u:
u.append(x)
return u
# From Alex Martelli,
# https://code.activestate.com/recipes/52560
# ASPN: Python Cookbook: Remove duplicates from a sequence
# First comment, dated 2001/10/13.
# (Also in the printed Python Cookbook.)
# This not currently used, in favor of the next function...
[docs]def uniquer(seq, idfun=None):
def default_idfun(x):
return x
if not idfun:
idfun = default_idfun
seen = {}
result = []
result_append = result.append # perf: avoid repeated method lookups
for item in seq:
marker = idfun(item)
if marker in seen:
continue
seen[marker] = 1
result_append(item)
return result
# A more efficient implementation of Alex's uniquer(), this avoids the
# idfun() argument and function-call overhead by assuming that all
# items in the sequence are hashable. Order-preserving.
[docs]def uniquer_hashables(seq):
seen = {}
result = []
result_append = result.append # perf: avoid repeated method lookups
for item in seq:
if item not in seen:
seen[item] = 1
result_append(item)
return result
# Recipe 19.11 "Reading Lines with Continuation Characters",
# by Alex Martelli, straight from the Python CookBook (2nd edition).
[docs]def logical_lines(physical_lines, joiner=''.join):
logical_line = []
for line in physical_lines:
stripped = line.rstrip()
if stripped.endswith('\\'):
# a line which continues w/the next physical line
logical_line.append(stripped[:-1])
else:
# a line which does not continue, end of logical line
logical_line.append(line)
yield joiner(logical_line)
logical_line = []
if logical_line:
# end of sequence implies end of last logical line
yield joiner(logical_line)
[docs]class LogicalLines:
""" Wrapper class for the logical_lines method.
Allows us to read all "logical" lines at once from a given file object.
"""
def __init__(self, fileobj):
self.fileobj = fileobj
[docs] def readlines(self):
return list(logical_lines(self.fileobj))
[docs]class UniqueList(UserList):
"""A list which maintains uniqueness.
Uniquing is lazy: rather than being assured on list changes, it is fixed
up on access by those methods which need to act on a uniqe list to be
correct. That means things like "in" don't have to eat the uniquing time.
"""
def __init__(self, initlist=None):
super().__init__(initlist)
self.unique = True
def __make_unique(self):
if not self.unique:
self.data = uniquer_hashables(self.data)
self.unique = True
def __repr__(self):
self.__make_unique()
return super().__repr__()
def __lt__(self, other):
self.__make_unique()
return super().__lt__(other)
def __le__(self, other):
self.__make_unique()
return super().__le__(other)
def __eq__(self, other):
self.__make_unique()
return super().__eq__(other)
def __ne__(self, other):
self.__make_unique()
return super().__ne__(other)
def __gt__(self, other):
self.__make_unique()
return super().__gt__(other)
def __ge__(self, other):
self.__make_unique()
return super().__ge__(other)
# __contains__ doesn't need to worry about uniquing, inherit
def __len__(self):
self.__make_unique()
return super().__len__()
def __getitem__(self, i):
self.__make_unique()
return super().__getitem__(i)
def __setitem__(self, i, item):
super().__setitem__(i, item)
self.unique = False
# __delitem__ doesn't need to worry about uniquing, inherit
def __add__(self, other):
result = super().__add__(other)
result.unique = False
return result
def __radd__(self, other):
result = super().__radd__(other)
result.unique = False
return result
def __iadd__(self, other):
result = super().__iadd__(other)
result.unique = False
return result
def __mul__(self, other):
result = super().__mul__(other)
result.unique = False
return result
def __rmul__(self, other):
result = super().__rmul__(other)
result.unique = False
return result
def __imul__(self, other):
result = super().__imul__(other)
result.unique = False
return result
[docs] def append(self, item):
super().append(item)
self.unique = False
[docs] def insert(self, i, item):
super().insert(i, item)
self.unique = False
[docs] def count(self, item):
self.__make_unique()
return super().count(item)
[docs] def index(self, item, *args):
self.__make_unique()
return super().index(item, *args)
[docs] def reverse(self):
self.__make_unique()
super().reverse()
# TODO: Py3.8: def sort(self, /, *args, **kwds):
[docs] def sort(self, *args, **kwds):
self.__make_unique()
return super().sort(*args, **kwds)
[docs] def extend(self, other):
super().extend(other)
self.unique = False
[docs]class Unbuffered:
"""A proxy that wraps a file object, flushing after every write.
Delegates everything else to the wrapped object.
"""
def __init__(self, file):
self.file = file
[docs] def write(self, arg):
# Stdout might be connected to a pipe that has been closed
# by now. The most likely reason for the pipe being closed
# is that the user has press ctrl-c. It this is the case,
# then SCons is currently shutdown. We therefore ignore
# IOError's here so that SCons can continue and shutdown
# properly so that the .sconsign is correctly written
# before SCons exits.
with suppress(IOError):
self.file.write(arg)
self.file.flush()
[docs] def writelines(self, arg):
with suppress(IOError):
self.file.writelines(arg)
self.file.flush()
def __getattr__(self, attr):
return getattr(self.file, attr)
[docs]def make_path_relative(path) -> str:
"""Converts an absolute path name to a relative pathname."""
if os.path.isabs(path):
drive_s, path = os.path.splitdrive(path)
if not drive_s:
path=re.compile(r"/*(.*)").findall(path)[0]
else:
path=path[1:]
assert not os.path.isabs(path), path
return path
# The original idea for AddMethod() came from the
# following post to the ActiveState Python Cookbook:
#
# ASPN: Python Cookbook : Install bound methods in an instance
# https://code.activestate.com/recipes/223613
#
# Changed as follows:
# * Switched the installmethod() "object" and "function" arguments,
# so the order reflects that the left-hand side is the thing being
# "assigned to" and the right-hand side is the value being assigned.
# * The instance/class detection is changed a bit, as it's all
# new-style classes now with Py3.
# * The by-hand construction of the function object from renamefunction()
# is not needed, the remaining bit is now used inline in AddMethod.
[docs]def AddMethod(obj, function, name=None):
"""Adds a method to an object.
Adds `function` to `obj` if `obj` is a class object.
Adds `function` as a bound method if `obj` is an instance object.
If `obj` looks like an environment instance, use `MethodWrapper`
to add it. If `name` is supplied it is used as the name of `function`.
Although this works for any class object, the intent as a public
API is to be used on Environment, to be able to add a method to all
construction environments; it is preferred to use env.AddMethod
to add to an individual environment.
>>> class A:
... ...
>>> a = A()
>>> def f(self, x, y):
... self.z = x + y
>>> AddMethod(A, f, "add")
>>> a.add(2, 4)
>>> print(a.z)
6
>>> a.data = ['a', 'b', 'c', 'd', 'e', 'f']
>>> AddMethod(a, lambda self, i: self.data[i], "listIndex")
>>> print(a.listIndex(3))
d
"""
if name is None:
name = function.__name__
else:
# "rename"
function = FunctionType(
function.__code__, function.__globals__, name, function.__defaults__
)
if hasattr(obj, '__class__') and obj.__class__ is not type:
# obj is an instance, so it gets a bound method.
if hasattr(obj, "added_methods"):
method = MethodWrapper(obj, function, name)
obj.added_methods.append(method)
else:
method = MethodType(function, obj)
else:
# obj is a class
method = function
setattr(obj, name, method)
# Default hash function and format. SCons-internal.
DEFAULT_HASH_FORMATS = ['md5', 'sha1', 'sha256']
ALLOWED_HASH_FORMATS = []
_HASH_FUNCTION = None
_HASH_FORMAT = None
[docs]def _attempt_init_of_python_3_9_hash_object(hash_function_object, sys_used=sys):
"""Python 3.9 and onwards lets us initialize the hash function object with the
key "usedforsecurity"=false. This lets us continue to use algorithms that have
been deprecated either by FIPS or by Python itself, as the MD5 algorithm SCons
prefers is not being used for security purposes as much as a short, 32 char
hash that is resistant to accidental collisions.
In prior versions of python, hashlib returns a native function wrapper, which
errors out when it's queried for the optional parameter, so this function
wraps that call.
It can still throw a ValueError if the initialization fails due to FIPS
compliance issues, but that is assumed to be the responsibility of the caller.
"""
if hash_function_object is None:
return None
# https://stackoverflow.com/a/11887885 details how to check versions with the "packaging" library.
# however, for our purposes checking the version is greater than or equal to 3.9 is good enough, as
# the API is guaranteed to have support for the 'usedforsecurity' flag in 3.9. See
# https://docs.python.org/3/library/hashlib.html#:~:text=usedforsecurity for the version support notes.
if (sys_used.version_info.major > 3) or (sys_used.version_info.major == 3 and sys_used.version_info.minor >= 9):
return hash_function_object(usedforsecurity=False)
# note that this can throw a ValueError in FIPS-enabled versions of Linux prior to 3.9
# the OpenSSL hashlib will throw on first init here, but that is assumed to be responsibility of
# the caller to diagnose the ValueError & potentially display the error to screen.
return hash_function_object()
[docs]def _set_allowed_viable_default_hashes(hashlib_used, sys_used=sys):
"""Checks if SCons has ability to call the default algorithms normally supported.
This util class is sometimes called prior to setting the user-selected hash algorithm,
meaning that on FIPS-compliant systems the library would default-initialize MD5
and throw an exception in set_hash_format. A common case is using the SConf options,
which can run prior to main, and thus ignore the options.hash_format variable.
This function checks the DEFAULT_HASH_FORMATS and sets the ALLOWED_HASH_FORMATS
to only the ones that can be called. In Python >= 3.9 this will always default to
MD5 as in Python 3.9 there is an optional attribute "usedforsecurity" set for the method.
Throws if no allowed hash formats are detected.
"""
global ALLOWED_HASH_FORMATS
_last_error = None
# note: if you call this method repeatedly, example using timeout, this is needed.
# otherwise it keeps appending valid formats to the string
ALLOWED_HASH_FORMATS = []
for test_algorithm in DEFAULT_HASH_FORMATS:
_test_hash = getattr(hashlib_used, test_algorithm, None)
# we know hashlib claims to support it... check to see if we can call it.
if _test_hash is not None:
# the hashing library will throw an exception on initialization in FIPS mode,
# meaning if we call the default algorithm returned with no parameters, it'll
# throw if it's a bad algorithm, otherwise it will append it to the known
# good formats.
try:
_attempt_init_of_python_3_9_hash_object(_test_hash, sys_used)
ALLOWED_HASH_FORMATS.append(test_algorithm)
except ValueError as e:
_last_error = e
continue
if len(ALLOWED_HASH_FORMATS) == 0:
from SCons.Errors import SConsEnvironmentError # pylint: disable=import-outside-toplevel
# chain the exception thrown with the most recent error from hashlib.
raise SConsEnvironmentError(
'No usable hash algorithms found.'
'Most recent error from hashlib attached in trace.'
) from _last_error
return
_set_allowed_viable_default_hashes(hashlib)
[docs]def _attempt_get_hash_function(hash_name, hashlib_used=hashlib, sys_used=sys):
"""Wrapper used to try to initialize a hash function given.
If successful, returns the name of the hash function back to the user.
Otherwise returns None.
"""
try:
_fetch_hash = getattr(hashlib_used, hash_name, None)
if _fetch_hash is None:
return None
_attempt_init_of_python_3_9_hash_object(_fetch_hash, sys_used)
return hash_name
except ValueError:
# if attempt_init_of_python_3_9 throws, this is typically due to FIPS being enabled
# however, if we get to this point, the viable hash function check has either been
# bypassed or otherwise failed to properly restrict the user to only the supported
# functions. As such throw the UserError as an internal assertion-like error.
return None
# Ensure that this is initialized in case either:
# 1. This code is running in a unit test.
# 2. This code is running in a consumer that does hash operations while
# SConscript files are being loaded.
set_hash_format(None)
[docs]def get_current_hash_algorithm_used():
"""Returns the current hash algorithm name used.
Where the python version >= 3.9, this is expected to return md5.
If python's version is <= 3.8, this returns md5 on non-FIPS-mode platforms, and
sha1 or sha256 on FIPS-mode Linux platforms.
This function is primarily useful for testing, where one expects a value to be
one of N distinct hashes, and therefore the test needs to know which hash to select.
"""
return _HASH_FUNCTION
[docs]def _get_hash_object(hash_format, hashlib_used=hashlib, sys_used=sys):
"""Allocates a hash object using the requested hash format.
Args:
hash_format: Hash format to use.
Returns:
hashlib object.
"""
if hash_format is None:
if _HASH_FUNCTION is None:
from SCons.Errors import UserError # pylint: disable=import-outside-toplevel
raise UserError('There is no default hash function. Did you call '
'a hashing function before SCons was initialized?')
return _attempt_init_of_python_3_9_hash_object(getattr(hashlib_used, _HASH_FUNCTION, None), sys_used)
if not hasattr(hashlib, hash_format):
from SCons.Errors import UserError # pylint: disable=import-outside-toplevel
raise UserError(
'Hash format "%s" is not available in your Python interpreter.' %
hash_format)
return _attempt_init_of_python_3_9_hash_object(getattr(hashlib, hash_format), sys_used)
[docs]def hash_signature(s, hash_format=None):
"""
Generate hash signature of a string
Args:
s: either string or bytes. Normally should be bytes
hash_format: Specify to override default hash format
Returns:
String of hex digits representing the signature
"""
m = _get_hash_object(hash_format)
try:
m.update(to_bytes(s))
except TypeError:
m.update(to_bytes(str(s)))
return m.hexdigest()
[docs]def hash_file_signature(fname, chunksize=65536, hash_format=None):
"""
Generate the md5 signature of a file
Args:
fname: file to hash
chunksize: chunk size to read
hash_format: Specify to override default hash format
Returns:
String of Hex digits representing the signature
"""
m = _get_hash_object(hash_format)
with open(fname, "rb") as f:
while True:
blck = f.read(chunksize)
if not blck:
break
m.update(to_bytes(blck))
return m.hexdigest()
[docs]def hash_collect(signatures, hash_format=None):
"""
Collects a list of signatures into an aggregate signature.
Args:
signatures: a list of signatures
hash_format: Specify to override default hash format
Returns:
the aggregate signature
"""
if len(signatures) == 1:
return signatures[0]
return hash_signature(', '.join(signatures), hash_format)
_MD5_WARNING_SHOWN = False
[docs]def _show_md5_warning(function_name):
"""Shows a deprecation warning for various MD5 functions."""
global _MD5_WARNING_SHOWN
if not _MD5_WARNING_SHOWN:
import SCons.Warnings # pylint: disable=import-outside-toplevel
SCons.Warnings.warn(SCons.Warnings.DeprecatedWarning,
"Function %s is deprecated" % function_name)
_MD5_WARNING_SHOWN = True
[docs]def MD5signature(s):
"""Deprecated. Use :func:`hash_signature` instead."""
_show_md5_warning("MD5signature")
return hash_signature(s)
[docs]def MD5filesignature(fname, chunksize=65536):
"""Deprecated. Use :func:`hash_file_signature` instead."""
_show_md5_warning("MD5filesignature")
return hash_file_signature(fname, chunksize)
[docs]def MD5collect(signatures):
"""Deprecated. Use :func:`hash_collect` instead."""
_show_md5_warning("MD5collect")
return hash_collect(signatures)
[docs]def silent_intern(x):
"""
Perform :mod:`sys.intern` on the passed argument and return the result.
If the input is ineligible for interning the original argument is
returned and no exception is thrown.
"""
try:
return sys.intern(x)
except TypeError:
return x
# From Dinu C. Gherman,
# Python Cookbook, second edition, recipe 6.17, p. 277.
# Also: https://code.activestate.com/recipes/68205
# ASPN: Python Cookbook: Null Object Design Pattern
[docs]class Null:
""" Null objects always and reliably "do nothing." """
def __new__(cls, *args, **kwargs):
if '_instance' not in vars(cls):
cls._instance = super(Null, cls).__new__(cls, *args, **kwargs)
return cls._instance
def __init__(self, *args, **kwargs):
pass
def __call__(self, *args, **kwargs):
return self
def __repr__(self):
return "Null(0x%08X)" % id(self)
def __bool__(self):
return False
def __getattr__(self, name):
return self
def __setattr__(self, name, value):
return self
def __delattr__(self, name):
return self
[docs]class NullSeq(Null):
""" A Null object that can also be iterated over. """
def __len__(self):
return 0
def __iter__(self):
return iter(())
def __getitem__(self, i):
return self
def __delitem__(self, i):
return self
def __setitem__(self, i, v):
return self
[docs]def to_bytes(s) -> bytes:
if s is None:
return b'None'
if isinstance(s, (bytes, bytearray)):
# if already bytes return.
return s
return bytes(s, 'utf-8')
[docs]def to_str(s) -> str:
if s is None:
return 'None'
if is_String(s):
return s
return str(s, 'utf-8')
[docs]def cmp(a, b) -> bool:
"""A cmp function because one is no longer available in python3."""
return (a > b) - (a < b)
[docs]def get_env_bool(env, name, default=False) -> bool:
"""Convert a construction variable to bool.
If the value of `name` in `env` is 'true', 'yes', 'y', 'on' (case
insensitive) or anything convertible to int that yields non-zero then
return ``True``; if 'false', 'no', 'n', 'off' (case insensitive)
or a number that converts to integer zero return ``False``.
Otherwise, return `default`.
Args:
env: construction environment, or any dict-like object
name: name of the variable
default: value to return if `name` not in `env` or cannot
be converted (default: False)
Returns:
the "truthiness" of `name`
"""
try:
var = env[name]
except KeyError:
return default
try:
return bool(int(var))
except ValueError:
if str(var).lower() in ('true', 'yes', 'y', 'on'):
return True
if str(var).lower() in ('false', 'no', 'n', 'off'):
return False
return default
[docs]def get_os_env_bool(name, default=False) -> bool:
"""Convert an environment variable to bool.
Conversion is the same as for :func:`get_env_bool`.
"""
return get_env_bool(os.environ, name, default)
[docs]def print_time():
"""Hack to return a value from Main if can't import Main."""
# pylint: disable=redefined-outer-name,import-outside-toplevel
from SCons.Script.Main import print_time
return print_time
# Local Variables:
# tab-width:4
# indent-tabs-mode:nil
# End:
# vim: set expandtab tabstop=4 shiftwidth=4: