Package pyxmpp :: Module xmppstringprep

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# Source Code for Module pyxmpp.xmppstringprep

      1  #
      2  # (C) Copyright 2003-2010 Jacek Konieczny <jajcus@jajcus.net>
      3  #
      4  # This program is free software; you can redistribute it and/or modify
      5  # it under the terms of the GNU Lesser General Public License Version
      6  # 2.1 as published by the Free Software Foundation.
      7  #
      8  # This program is distributed in the hope that it will be useful,
      9  # but WITHOUT ANY WARRANTY; without even the implied warranty of
     10  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     11  # GNU Lesser General Public License for more details.
     12  #
     13  # You should have received a copy of the GNU Lesser General Public
     14  # License along with this program; if not, write to the Free Software
     15  # Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
     16  #
     17  # pylint treats "import stringprep" like depreciated "import string"
     18  # pylint: disable-msg=W0402
     19
     20  """Nodeprep and resourceprep stringprep profiles.
     21
     22  Normative reference:
     23    - `RFC 3920 <http://www.ietf.org/rfc/rfc3920.txt>`__
     24  """
     25
     26  __docformat__="restructuredtext en"
     27
     28  import stringprep
     29  import unicodedata
     30  from pyxmpp.exceptions import StringprepError
     31
     32 -class LookupFunction:
     33      """Class for looking up RFC 3454 tables using function.
     34
     35      :Ivariables:
     36          - `lookup`: the lookup function."""
     37 -    def __init__(self,function):
     38          """Initialize `LookupFunction` object.
     39
     40          :Parameters:
     41              - `function`: function taking character code as input and returning
     42                `bool` value or the mapped for `code`."""
     43          self.lookup=function
     44
     45 -class LookupTable:
     46      """Class for looking up RFC 3454 tables using a dictionary and/or list of ranges."""
     47 -    def __init__(self,singles,ranges):
     48          """Initialize `LookupTable` object.
     49
     50          :Parameters:
     51              - `singles`: dictionary mapping Unicode characters into other Unicode characters.
     52              - `ranges`: list of ``((start,end),value)`` tuples mapping codes in range (start,end)
     53                to the value."""
     54          self.singles=singles
     55          self.ranges=ranges
     56
     57 -    def lookup(self,c):
     58          """Do Unicode character lookup.
     59
     60          :Parameters:
     61              - `c`: Unicode character to look up.
     62
     63          :return: the mapped value."""
     64          if self.singles.has_key(c):
     65              return self.singles[c]
     66          c=ord(c)
     67          for (start,end),value in self.ranges:
     68              if c<start:
     69                  return None
     70              if c<=end:
     71                  return value
     72          return None
     73
     74  A_1=LookupFunction(stringprep.in_table_a1)
     75
     76 -def b1_mapping(uc):
     77      """Do RFC 3454 B.1 table mapping.
     78
     79      :Parameters:
     80          - `uc`: Unicode character to map.
     81
     82      :returns: u"" if there is `uc` code in the table, `None` otherwise."""
     83      if stringprep.in_table_b1(uc):
     84          return u""
     85      else:
     86          return None
     87
     88  B_1=LookupFunction(b1_mapping)
     89  B_2=LookupFunction(stringprep.map_table_b2)
     90  B_3=LookupFunction(stringprep.map_table_b3)
     91  C_1_1=LookupFunction(stringprep.in_table_c11)
     92  C_1_2=LookupFunction(stringprep.in_table_c12)
     93  C_2_1=LookupFunction(stringprep.in_table_c21)
     94  C_2_2=LookupFunction(stringprep.in_table_c22)
     95  C_3=LookupFunction(stringprep.in_table_c3)
     96  C_4=LookupFunction(stringprep.in_table_c4)
     97  C_5=LookupFunction(stringprep.in_table_c5)
     98  C_6=LookupFunction(stringprep.in_table_c6)
     99  C_7=LookupFunction(stringprep.in_table_c7)
    100  C_8=LookupFunction(stringprep.in_table_c8)
    101  C_9=LookupFunction(stringprep.in_table_c9)
    102  D_1=LookupFunction(stringprep.in_table_d1)
    103  D_2=LookupFunction(stringprep.in_table_d2)
    104
    105 -def nfkc(data):
    106      """Do NFKC normalization of Unicode data.
    107
    108      :Parameters:
    109          - `data`: list of Unicode characters or Unicode string.
    110
    111      :return: normalized Unicode string."""
    112      if type(data) is list:
    113          data=u"".join(data)
    114      return unicodedata.normalize("NFKC",data)
    115
    116 -class Profile:
    117      """Base class for stringprep profiles."""
    118      cache_items=[]
    119 -    def __init__(self,unassigned,mapping,normalization,prohibited,bidi=1):
    120          """Initialize Profile object.
    121
    122          :Parameters:
    123              - `unassigned`: the lookup table with unassigned codes
    124              - `mapping`: the lookup table with character mappings
    125              - `normalization`: the normalization function
    126              - `prohibited`: the lookup table with prohibited characters
    127              - `bidi`: if True then bidirectional checks should be done
    128          """
    129          self.unassigned=unassigned
    130          self.mapping=mapping
    131          self.normalization=normalization
    132          self.prohibited=prohibited
    133          self.bidi=bidi
    134          self.cache={}
    135
    136 -    def prepare(self,data):
    137          """Complete string preparation procedure for 'stored' strings.
    138          (includes checks for unassigned codes)
    139
    140          :Parameters:
    141              - `data`: Unicode string to prepare.
    142
    143          :return: prepared string
    144
    145          :raise StringprepError: if the preparation fails
    146          """
    147          r=self.cache.get(data)
    148          if r is not None:
    149              return r
    150          s=self.map(data)
    151          if self.normalization:
    152              s=self.normalization(s)
    153          s=self.prohibit(s)
    154          s=self.check_unassigned(s)
    155          if self.bidi:
    156              s=self.check_bidi(s)
    157          if type(s) is list:
    158              s=u"".string.join()
    159          if len(self.cache_items)>=stringprep_cache_size:
    160              remove=self.cache_items[:-stringprep_cache_size/2]
    161              for profile,key in remove:
    162                  try:
    163                      del profile.cache[key]
    164                  except KeyError:
    165                      pass
    166              self.cache_items[:]=self.cache_items[-stringprep_cache_size/2:]
    167          self.cache_items.append((self,data))
    168          self.cache[data]=s
    169          return s
    170
    171 -    def prepare_query(self,s):
    172          """Complete string preparation procedure for 'query' strings.
    173          (without checks for unassigned codes)
    174
    175          :Parameters:
    176              - `s`: Unicode string to prepare.
    177
    178          :return: prepared string
    179
    180          :raise StringprepError: if the preparation fails
    181          """
    182
    183          s=self.map(s)
    184          if self.normalization:
    185              s=self.normalization(s)
    186          s=self.prohibit(s)
    187          if self.bidi:
    188              s=self.check_bidi(s)
    189          if type(s) is list:
    190              s=u"".string.join(s)
    191          return s
    192
    193 -    def map(self,s):
    194          """Mapping part of string preparation."""
    195          r=[]
    196          for c in s:
    197              rc=None
    198              for t in self.mapping:
    199                  rc=t.lookup(c)
    200                  if rc is not None:
    201                      break
    202              if rc is not None:
    203                  r.append(rc)
    204              else:
    205                  r.append(c)
    206          return r
    207
    208 -    def prohibit(self,s):
    209          """Checks for prohibited characters."""
    210          for c in s:
    211              for t in self.prohibited:
    212                  if t.lookup(c):
    213                      raise StringprepError,"Prohibited character: %r" % (c,)
    214          return s
    215
    216 -    def check_unassigned(self,s):
    217          """Checks for unassigned character codes."""
    218          for c in s:
    219              for t in self.unassigned:
    220                  if t.lookup(c):
    221                      raise StringprepError,"Unassigned character: %r" % (c,)
    222          return s
    223
    224 -    def check_bidi(self,s):
    225          """Checks if sting is valid for bidirectional printing."""
    226          has_l=0
    227          has_ral=0
    228          for c in s:
    229              if D_1.lookup(c):
    230                  has_ral=1
    231              elif D_2.lookup(c):
    232                  has_l=1
    233          if has_l and has_ral:
    234              raise StringprepError,"Both RandALCat and LCat characters present"
    235          if has_l and (D_1.lookup(s[0]) is None or D_1.lookup(s[-1]) is None):
    236              raise StringprepError,"The first and the last character must be RandALCat"
    237          return s
    238
    239  nodeprep=Profile(
    240      unassigned=(A_1,),
    241      mapping=(B_1,B_2),
    242      normalization=nfkc,
    243      prohibited=(C_1_1,C_1_2,C_2_1,C_2_2,C_3,C_4,C_5,C_6,C_7,C_8,C_9,
    244              LookupTable({u'"':True,u'&':True,u"'":True,u"/":True,
    245                      u":":True,u"<":True,u">":True,u"@":True},()) ),
    246      bidi=1)
    247
    248  resourceprep=Profile(
    249      unassigned=(A_1,),
    250      mapping=(B_1,),
    251      normalization=nfkc,
    252      prohibited=(C_1_2,C_2_1,C_2_2,C_3,C_4,C_5,C_6,C_7,C_8,C_9),
    253      bidi=1)
    254
    255  stringprep_cache_size=1000
    256 -def set_stringprep_cache_size(size):
    257      """Modify stringprep cache size.
    258
    259      :Parameters:
    260          - `size`: new cache size"""
    261      global stringprep_cache_size
    262      stringprep_cache_size=size
    263      if len(Profile.cache_items)>size:
    264          remove=Profile.cache_items[:-size]
    265          for profile,key in remove:
    266              try:
    267                  del profile.cache[key]
    268              except KeyError:
    269                  pass
    270          Profile.cache_items=Profile.cache_items[-size:]
    271
    272  # vi: sts=4 et sw=4
    273