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lib/cherrypy/_cpcompat.py

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+"""Compatibility code for using CherryPy with various versions of Python.
+
+CherryPy 3.2 is compatible with Python versions 2.3+. This module provides a
+useful abstraction over the differences between Python versions, sometimes by
+preferring a newer idiom, sometimes an older one, and sometimes a custom one.
+
+In particular, Python 2 uses str and '' for byte strings, while Python 3
+uses str and '' for unicode strings. We will call each of these the 'native
+string' type for each version. Because of this major difference, this module
+provides new 'bytestr', 'unicodestr', and 'nativestr' attributes, as well as
+two functions: 'ntob', which translates native strings (of type 'str') into
+byte strings regardless of Python version, and 'ntou', which translates native
+strings to unicode strings. This also provides a 'BytesIO' name for dealing
+specifically with bytes, and a 'StringIO' name for dealing with native strings.
+It also provides a 'base64_decode' function with native strings as input and
+output.
+"""
+import os
+import re
+import sys
+import threading
+
+if sys.version_info >= (3, 0):
+    py3k = True
+    bytestr = bytes
+    unicodestr = str
+    nativestr = unicodestr
+    basestring = (bytes, str)
+
+    def ntob(n, encoding='ISO-8859-1'):
+        """Return the given native string as a byte string in the given
+        encoding.
+        """
+        assert_native(n)
+        # In Python 3, the native string type is unicode
+        return n.encode(encoding)
+
+    def ntou(n, encoding='ISO-8859-1'):
+        """Return the given native string as a unicode string with the given
+        encoding.
+        """
+        assert_native(n)
+        # In Python 3, the native string type is unicode
+        return n
+
+    def tonative(n, encoding='ISO-8859-1'):
+        """Return the given string as a native string in the given encoding."""
+        # In Python 3, the native string type is unicode
+        if isinstance(n, bytes):
+            return n.decode(encoding)
+        return n
+    # type("")
+    from io import StringIO
+    # bytes:
+    from io import BytesIO as BytesIO
+else:
+    # Python 2
+    py3k = False
+    bytestr = str
+    unicodestr = unicode
+    nativestr = bytestr
+    basestring = basestring
+
+    def ntob(n, encoding='ISO-8859-1'):
+        """Return the given native string as a byte string in the given
+        encoding.
+        """
+        assert_native(n)
+        # In Python 2, the native string type is bytes. Assume it's already
+        # in the given encoding, which for ISO-8859-1 is almost always what
+        # was intended.
+        return n
+
+    def ntou(n, encoding='ISO-8859-1'):
+        """Return the given native string as a unicode string with the given
+        encoding.
+        """
+        assert_native(n)
+        # In Python 2, the native string type is bytes.
+        # First, check for the special encoding 'escape'. The test suite uses
+        # this to signal that it wants to pass a string with embedded \uXXXX
+        # escapes, but without having to prefix it with u'' for Python 2,
+        # but no prefix for Python 3.
+        if encoding == 'escape':
+            return unicode(
+                re.sub(r'\\u([0-9a-zA-Z]{4})',
+                       lambda m: unichr(int(m.group(1), 16)),
+                       n.decode('ISO-8859-1')))
+        # Assume it's already in the given encoding, which for ISO-8859-1
+        # is almost always what was intended.
+        return n.decode(encoding)
+
+    def tonative(n, encoding='ISO-8859-1'):
+        """Return the given string as a native string in the given encoding."""
+        # In Python 2, the native string type is bytes.
+        if isinstance(n, unicode):
+            return n.encode(encoding)
+        return n
+    try:
+        # type("")
+        from cStringIO import StringIO
+    except ImportError:
+        # type("")
+        from StringIO import StringIO
+    # bytes:
+    BytesIO = StringIO
+
+
+def assert_native(n):
+    if not isinstance(n, nativestr):
+        raise TypeError("n must be a native str (got %s)" % type(n).__name__)
+
+try:
+    set = set
+except NameError:
+    from sets import Set as set
+
+try:
+    # Python 3.1+
+    from base64 import decodebytes as _base64_decodebytes
+except ImportError:
+    # Python 3.0-
+    # since CherryPy claims compability with Python 2.3, we must use
+    # the legacy API of base64
+    from base64 import decodestring as _base64_decodebytes
+
+
+def base64_decode(n, encoding='ISO-8859-1'):
+    """Return the native string base64-decoded (as a native string)."""
+    if isinstance(n, unicodestr):
+        b = n.encode(encoding)
+    else:
+        b = n
+    b = _base64_decodebytes(b)
+    if nativestr is unicodestr:
+        return b.decode(encoding)
+    else:
+        return b
+
+try:
+    # Python 2.5+
+    from hashlib import md5
+except ImportError:
+    from md5 import new as md5
+
+try:
+    # Python 2.5+
+    from hashlib import sha1 as sha
+except ImportError:
+    from sha import new as sha
+
+try:
+    sorted = sorted
+except NameError:
+    def sorted(i):
+        i = i[:]
+        i.sort()
+        return i
+
+try:
+    reversed = reversed
+except NameError:
+    def reversed(x):
+        i = len(x)
+        while i > 0:
+            i -= 1
+            yield x[i]
+
+try:
+    # Python 3
+    from urllib.parse import urljoin, urlencode
+    from urllib.parse import quote, quote_plus
+    from urllib.request import unquote, urlopen
+    from urllib.request import parse_http_list, parse_keqv_list
+except ImportError:
+    # Python 2
+    from urlparse import urljoin
+    from urllib import urlencode, urlopen
+    from urllib import quote, quote_plus
+    from urllib import unquote
+    from urllib2 import parse_http_list, parse_keqv_list
+
+try:
+    from threading import local as threadlocal
+except ImportError:
+    from cherrypy._cpthreadinglocal import local as threadlocal
+
+try:
+    dict.iteritems
+    # Python 2
+    iteritems = lambda d: d.iteritems()
+    copyitems = lambda d: d.items()
+except AttributeError:
+    # Python 3
+    iteritems = lambda d: d.items()
+    copyitems = lambda d: list(d.items())
+
+try:
+    dict.iterkeys
+    # Python 2
+    iterkeys = lambda d: d.iterkeys()
+    copykeys = lambda d: d.keys()
+except AttributeError:
+    # Python 3
+    iterkeys = lambda d: d.keys()
+    copykeys = lambda d: list(d.keys())
+
+try:
+    dict.itervalues
+    # Python 2
+    itervalues = lambda d: d.itervalues()
+    copyvalues = lambda d: d.values()
+except AttributeError:
+    # Python 3
+    itervalues = lambda d: d.values()
+    copyvalues = lambda d: list(d.values())
+
+try:
+    # Python 3
+    import builtins
+except ImportError:
+    # Python 2
+    import __builtin__ as builtins
+
+try:
+    # Python 2. We try Python 2 first clients on Python 2
+    # don't try to import the 'http' module from cherrypy.lib
+    from Cookie import SimpleCookie, CookieError
+    from httplib import BadStatusLine, HTTPConnection, IncompleteRead
+    from httplib import NotConnected
+    from BaseHTTPServer import BaseHTTPRequestHandler
+except ImportError:
+    # Python 3
+    from http.cookies import SimpleCookie, CookieError
+    from http.client import BadStatusLine, HTTPConnection, IncompleteRead
+    from http.client import NotConnected
+    from http.server import BaseHTTPRequestHandler
+
+# Some platforms don't expose HTTPSConnection, so handle it separately
+if py3k:
+    try:
+        from http.client import HTTPSConnection
+    except ImportError:
+        # Some platforms which don't have SSL don't expose HTTPSConnection
+        HTTPSConnection = None
+else:
+    try:
+        from httplib import HTTPSConnection
+    except ImportError:
+        HTTPSConnection = None
+
+try:
+    # Python 2
+    xrange = xrange
+except NameError:
+    # Python 3
+    xrange = range
+
+import threading
+if hasattr(threading.Thread, "daemon"):
+    # Python 2.6+
+    def get_daemon(t):
+        return t.daemon
+
+    def set_daemon(t, val):
+        t.daemon = val
+else:
+    def get_daemon(t):
+        return t.isDaemon()
+
+    def set_daemon(t, val):
+        t.setDaemon(val)
+
+try:
+    from email.utils import formatdate
+
+    def HTTPDate(timeval=None):
+        return formatdate(timeval, usegmt=True)
+except ImportError:
+    from rfc822 import formatdate as HTTPDate
+
+try:
+    # Python 3
+    from urllib.parse import unquote as parse_unquote
+
+    def unquote_qs(atom, encoding, errors='strict'):
+        return parse_unquote(
+            atom.replace('+', ' '),
+            encoding=encoding,
+            errors=errors)
+except ImportError:
+    # Python 2
+    from urllib import unquote as parse_unquote
+
+    def unquote_qs(atom, encoding, errors='strict'):
+        return parse_unquote(atom.replace('+', ' ')).decode(encoding, errors)
+
+try:
+    # Prefer simplejson, which is usually more advanced than the builtin
+    # module.
+    import simplejson as json
+    json_decode = json.JSONDecoder().decode
+    _json_encode = json.JSONEncoder().iterencode
+except ImportError:
+    if sys.version_info >= (2, 6):
+        # Python >=2.6 : json is part of the standard library
+        import json
+        json_decode = json.JSONDecoder().decode
+        _json_encode = json.JSONEncoder().iterencode
+    else:
+        json = None
+
+        def json_decode(s):
+            raise ValueError('No JSON library is available')
+
+        def _json_encode(s):
+            raise ValueError('No JSON library is available')
+finally:
+    if json and py3k:
+        # The two Python 3 implementations (simplejson/json)
+        # outputs str. We need bytes.
+        def json_encode(value):
+            for chunk in _json_encode(value):
+                yield chunk.encode('utf8')
+    else:
+        json_encode = _json_encode
+
+
+try:
+    import cPickle as pickle
+except ImportError:
+    # In Python 2, pickle is a Python version.
+    # In Python 3, pickle is the sped-up C version.
+    import pickle
+
+try:
+    os.urandom(20)
+    import binascii
+
+    def random20():
+        return binascii.hexlify(os.urandom(20)).decode('ascii')
+except (AttributeError, NotImplementedError):
+    import random
+    # os.urandom not available until Python 2.4. Fall back to random.random.
+
+    def random20():
+        return sha('%s' % random.random()).hexdigest()
+
+try:
+    from _thread import get_ident as get_thread_ident
+except ImportError:
+    from thread import get_ident as get_thread_ident
+
+try:
+    # Python 3
+    next = next
+except NameError:
+    # Python 2
+    def next(i):
+        return i.next()
+
+if sys.version_info >= (3, 3):
+    Timer = threading.Timer
+    Event = threading.Event
+else:
+    # Python 3.2 and earlier
+    Timer = threading._Timer
+    Event = threading._Event
+
+# Prior to Python 2.6, the Thread class did not have a .daemon property.
+# This mix-in adds that property.
+
+
+class SetDaemonProperty:
+
+    def __get_daemon(self):
+        return self.isDaemon()
+
+    def __set_daemon(self, daemon):
+        self.setDaemon(daemon)
+
+    if sys.version_info < (2, 6):
+        daemon = property(__get_daemon, __set_daemon)