Initial Commit

lib/mako/util.py

@@ -0,0 +1,360 @@
+# mako/util.py
+# Copyright (C) 2006-2015 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
+
+import re
+import collections
+import codecs
+import os
+from mako import compat
+import operator
+
+def update_wrapper(decorated, fn):
+    decorated.__wrapped__ = fn
+    decorated.__name__ = fn.__name__
+    return decorated
+
+
+class PluginLoader(object):
+    def __init__(self, group):
+        self.group = group
+        self.impls = {}
+
+    def load(self, name):
+        if name in self.impls:
+            return self.impls[name]()
+        else:
+            import pkg_resources
+            for impl in pkg_resources.iter_entry_points(
+                                self.group,
+                                name):
+                self.impls[name] = impl.load
+                return impl.load()
+            else:
+                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, compat.octal("0775"))
+        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(object):
+    """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(object):
+    """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)
+            memo = lambda *a, **kw: 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(object):
+    """a very rudimentary buffer that is faster than StringIO,
+    but doesn't crash on unicode data like cStringIO."""
+
+    def __init__(self, encoding=None, errors='strict', as_unicode=False):
+        self.data = collections.deque()
+        self.encoding = encoding
+        if as_unicode:
+            self.delim = compat.u('')
+        else:
+            self.delim = ''
+        self.as_unicode = as_unicode
+        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(object):
+        def __init__(self, key, value):
+            self.key = key
+            self.value = value
+            self.timestamp = compat.time_func()
+        def __repr__(self):
+            return repr(self.value)
+
+    def __init__(self, capacity, threshold=.5):
+        self.capacity = capacity
+        self.threshold = threshold
+
+    def __getitem__(self, key):
+        item = dict.__getitem__(self, key)
+        item.timestamp = compat.time_func()
+        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]
+        else:
+            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:
+                import parser
+                parser.suite(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(object): 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'):
+    fp = open(path, mode)
+    try:
+        data = fp.read()
+        return data
+    finally:
+        fp.close()
+
+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()
+