# mako/util.py
# Copyright 2006-2022 the Mako authors and contributors <see AUTHORS file>
#
# This module is part of Mako and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php
from ast import parse
import codecs
import collections
import operator
import os
import re
import timeit
from .compat import importlib_metadata_get
def update_wrapper(decorated, fn):
decorated.__wrapped__ = fn
decorated.__name__ = fn.__name__
return decorated
class PluginLoader:
def __init__(self, group):
self.group = group
self.impls = {}
def load(self, name):
if name in self.impls:
return self.impls[name]()
for impl in importlib_metadata_get(self.group):
if impl.name == name:
self.impls[name] = impl.load
return impl.load()
from mako import exceptions
raise exceptions.RuntimeException(
"Can't load plugin %s %s" % (self.group, name)
)
def register(self, name, modulepath, objname):
def load():
mod = __import__(modulepath)
for token in modulepath.split(".")[1:]:
mod = getattr(mod, token)
return getattr(mod, objname)
self.impls[name] = load
def verify_directory(dir_):
"""create and/or verify a filesystem directory."""
tries = 0
while not os.path.exists(dir_):
try:
tries += 1
os.makedirs(dir_, 0o755)
except:
if tries > 5:
raise
def to_list(x, default=None):
if x is None:
return default
if not isinstance(x, (list, tuple)):
return [x]
else:
return x
class memoized_property:
"""A read-only @property that is only evaluated once."""
def __init__(self, fget, doc=None):
self.fget = fget
self.__doc__ = doc or fget.__doc__
self.__name__ = fget.__name__
def __get__(self, obj, cls):
if obj is None:
return self
obj.__dict__[self.__name__] = result = self.fget(obj)
return result
class memoized_instancemethod:
"""Decorate a method memoize its return value.
Best applied to no-arg methods: memoization is not sensitive to
argument values, and will always return the same value even when
called with different arguments.
"""
def __init__(self, fget, doc=None):
self.fget = fget
self.__doc__ = doc or fget.__doc__
self.__name__ = fget.__name__
def __get__(self, obj, cls):
if obj is None:
return self
def oneshot(*args, **kw):
result = self.fget(obj, *args, **kw)
def memo(*a, **kw):
return result
memo.__name__ = self.__name__
memo.__doc__ = self.__doc__
obj.__dict__[self.__name__] = memo
return result
oneshot.__name__ = self.__name__
oneshot.__doc__ = self.__doc__
return oneshot
class SetLikeDict(dict):
"""a dictionary that has some setlike methods on it"""
def union(self, other):
"""produce a 'union' of this dict and another (at the key level).
values in the second dict take precedence over that of the first"""
x = SetLikeDict(**self)
x.update(other)
return x
class FastEncodingBuffer:
"""a very rudimentary buffer that is faster than StringIO,
and supports unicode data."""
def __init__(self, encoding=None, errors="strict"):
self.data = collections.deque()
self.encoding = encoding
self.delim = ""
self.errors = errors
self.write = self.data.append
def truncate(self):
self.data = collections.deque()
self.write = self.data.append
def getvalue(self):
if self.encoding:
return self.delim.join(self.data).encode(
self.encoding, self.errors
)
else:
return self.delim.join(self.data)
class LRUCache(dict):
"""A dictionary-like object that stores a limited number of items,
discarding lesser used items periodically.
this is a rewrite of LRUCache from Myghty to use a periodic timestamp-based
paradigm so that synchronization is not really needed. the size management
is inexact.
"""
class _Item:
def __init__(self, key, value):
self.key = key
self.value = value
self.timestamp = timeit.default_timer()
def __repr__(self):
return repr(self.value)
def __init__(self, capacity, threshold=0.5):
self.capacity = capacity
self.threshold = threshold
def __getitem__(self, key):
item = dict.__getitem__(self, key)
item.timestamp = timeit.default_timer()
return item.value
def values(self):
return [i.value for i in dict.values(self)]
def setdefault(self, key, value):
if key in self:
return self[key]
self[key] = value
return value
def __setitem__(self, key, value):
item = dict.get(self, key)
if item is None:
item = self._Item(key, value)
dict.__setitem__(self, key, item)
else:
item.value = value
self._manage_size()
def _manage_size(self):
while len(self) > self.capacity + self.capacity * self.threshold:
bytime = sorted(
dict.values(self),
key=operator.attrgetter("timestamp"),
reverse=True,
)
for item in bytime[self.capacity :]:
try:
del self[item.key]
except KeyError:
# if we couldn't find a key, most likely some other thread
# broke in on us. loop around and try again
break
# Regexp to match python magic encoding line
_PYTHON_MAGIC_COMMENT_re = re.compile(
r"[ \t\f]* \# .* coding[=:][ \t]*([-\w.]+)", re.VERBOSE
)
def parse_encoding(fp):
"""Deduce the encoding of a Python source file (binary mode) from magic
comment.
It does this in the same way as the `Python interpreter`__
.. __: http://docs.python.org/ref/encodings.html
The ``fp`` argument should be a seekable file object in binary mode.
"""
pos = fp.tell()
fp.seek(0)
try:
line1 = fp.readline()
has_bom = line1.startswith(codecs.BOM_UTF8)
if has_bom:
line1 = line1[len(codecs.BOM_UTF8) :]
m = _PYTHON_MAGIC_COMMENT_re.match(line1.decode("ascii", "ignore"))
if not m:
try:
parse(line1.decode("ascii", "ignore"))
except (ImportError, SyntaxError):
# Either it's a real syntax error, in which case the source
# is not valid python source, or line2 is a continuation of
# line1, in which case we don't want to scan line2 for a magic
# comment.
pass
else:
line2 = fp.readline()
m = _PYTHON_MAGIC_COMMENT_re.match(
line2.decode("ascii", "ignore")
)
if has_bom:
if m:
raise SyntaxError(
"python refuses to compile code with both a UTF8"
" byte-order-mark and a magic encoding comment"
)
return "utf_8"
elif m:
return m.group(1)
else:
return None
finally:
fp.seek(pos)
def sorted_dict_repr(d):
"""repr() a dictionary with the keys in order.
Used by the lexer unit test to compare parse trees based on strings.
"""
keys = list(d.keys())
keys.sort()
return "{" + ", ".join("%r: %r" % (k, d[k]) for k in keys) + "}"
def restore__ast(_ast):
"""Attempt to restore the required classes to the _ast module if it
appears to be missing them
"""
if hasattr(_ast, "AST"):
return
_ast.PyCF_ONLY_AST = 2 << 9
m = compile(
"""\
def foo(): pass
class Bar: pass
if False: pass
baz = 'mako'
1 + 2 - 3 * 4 / 5
6 // 7 % 8 << 9 >> 10
11 & 12 ^ 13 | 14
15 and 16 or 17
-baz + (not +18) - ~17
baz and 'foo' or 'bar'
(mako is baz == baz) is not baz != mako
mako > baz < mako >= baz <= mako
mako in baz not in mako""",
"<unknown>",
"exec",
_ast.PyCF_ONLY_AST,
)
_ast.Module = type(m)
for cls in _ast.Module.__mro__:
if cls.__name__ == "mod":
_ast.mod = cls
elif cls.__name__ == "AST":
_ast.AST = cls
_ast.FunctionDef = type(m.body[0])
_ast.ClassDef = type(m.body[1])
_ast.If = type(m.body[2])
_ast.Name = type(m.body[3].targets[0])
_ast.Store = type(m.body[3].targets[0].ctx)
_ast.Str = type(m.body[3].value)
_ast.Sub = type(m.body[4].value.op)
_ast.Add = type(m.body[4].value.left.op)
_ast.Div = type(m.body[4].value.right.op)
_ast.Mult = type(m.body[4].value.right.left.op)
_ast.RShift = type(m.body[5].value.op)
_ast.LShift = type(m.body[5].value.left.op)
_ast.Mod = type(m.body[5].value.left.left.op)
_ast.FloorDiv = type(m.body[5].value.left.left.left.op)
_ast.BitOr = type(m.body[6].value.op)
_ast.BitXor = type(m.body[6].value.left.op)
_ast.BitAnd = type(m.body[6].value.left.left.op)
_ast.Or = type(m.body[7].value.op)
_ast.And = type(m.body[7].value.values[0].op)
_ast.Invert = type(m.body[8].value.right.op)
_ast.Not = type(m.body[8].value.left.right.op)
_ast.UAdd = type(m.body[8].value.left.right.operand.op)
_ast.USub = type(m.body[8].value.left.left.op)
_ast.Or = type(m.body[9].value.op)
_ast.And = type(m.body[9].value.values[0].op)
_ast.IsNot = type(m.body[10].value.ops[0])
_ast.NotEq = type(m.body[10].value.ops[1])
_ast.Is = type(m.body[10].value.left.ops[0])
_ast.Eq = type(m.body[10].value.left.ops[1])
_ast.Gt = type(m.body[11].value.ops[0])
_ast.Lt = type(m.body[11].value.ops[1])
_ast.GtE = type(m.body[11].value.ops[2])
_ast.LtE = type(m.body[11].value.ops[3])
_ast.In = type(m.body[12].value.ops[0])
_ast.NotIn = type(m.body[12].value.ops[1])
def read_file(path, mode="rb"):
with open(path, mode) as fp:
return fp.read()
def read_python_file(path):
fp = open(path, "rb")
try:
encoding = parse_encoding(fp)
data = fp.read()
if encoding:
data = data.decode(encoding)
return data
finally:
fp.close()
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