SCons/EnvironmentValues.py

   1 # MIT License
   2 #
   3 # Copyright The SCons Foundation
   4 #
   5 # Permission is hereby granted, free of charge, to any person obtaining
   6 # a copy of this software and associated documentation files (the
   7 # "Software"), to deal in the Software without restriction, including
   8 # without limitation the rights to use, copy, modify, merge, publish,
   9 # distribute, sublicense, and/or sell copies of the Software, and to
  10 # permit persons to whom the Software is furnished to do so, subject to
  11 # the following conditions:
  12 #
  13 # The above copyright notice and this permission notice shall be included
  14 # in all copies or substantial portions of the Software.
  15 #
  16 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
  17 # KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
  18 # WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  19 # NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  20 # LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  21 # OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  22 # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  23
  24 import re
  25
  26 _is_valid_var = re.compile(r'[_a-zA-Z]\w*$')
  27
  28 _rm = re.compile(r'\$[()]')
  29 _remove = re.compile(r'\$\([^$]*(\$[^)][^$]*)*\$\)')
  30
  31 # Regular expressions for splitting strings and handling substitutions,
  32 # for use by the scons_subst() and scons_subst_list() functions:
  33 #
  34 # The first expression compiled matches all of the $-introduced tokens
  35 # that we need to process in some way, and is used for substitutions.
  36 # The expressions it matches are:
  37 #
  38 #       "$$"
  39 #       "$("
  40 #       "$)"
  41 #       "$variable"             [must begin with alphabetic or underscore]
  42 #       "${any stuff}"
  43 #
  44 # The second expression compiled is used for splitting strings into tokens
  45 # to be processed, and it matches all of the tokens listed above, plus
  46 # the following that affect how arguments do or don't get joined together:
  47 #
  48 #       "   "                   [white space]
  49 #       "non-white-space"       [without any dollar signs]
  50 #       "$"                     [single dollar sign]
  51 #
  52 _dollar_exps_str = r'\$[\$\(\)]|\$[_a-zA-Z][\.\w]*|\${[^}]*}'
  53 _dollar_exps = re.compile(r'(%s)' % _dollar_exps_str)
  54 _separate_args = re.compile(r'(%s|\s+|[^\s$]+|\$)' % _dollar_exps_str)
  55
  56 # This regular expression is used to replace strings of multiple white
  57 # space characters in the string result from the scons_subst() function.
  58 _space_sep = re.compile(r'[\t ]+(?![^{]*})')
  59
  60 class ValueTypes:
  61     """
  62     Enum to store what type of value the variable holds.
  63     """
  64     UNKNOWN = 0
  65     STRING = 1
  66     CALLABLE = 2
  67     VARIABLE = 3
  68
  69
  70 class EnvironmentValue:
  71     """
  72     Hold a single value. We're going to cache parsed version of the file
  73     We're going to keep track of variables which feed into this values evaluation
  74     """
  75     def __init__(self, value) -> None:
  76         self.value = value
  77         self.var_type = ValueTypes.UNKNOWN
  78
  79         if callable(self.value):
  80             self.var_type = ValueTypes.CALLABLE
  81         else:
  82             self.parse_value()
  83
  84
  85     def parse_value(self) -> None:
  86         """
  87         Scan the string and break into component values
  88         """
  89
  90         try:
  91             if '$' not in self.value:
  92                 self._parsed = self.value
  93                 self.var_type = ValueTypes.STRING
  94             else:
  95                 # Now we need to parse the specified string
  96                 result = _dollar_exps.sub(sub_match, args)
  97                 print(result)
  98         except TypeError:
  99             # likely callable? either way we don't parse
 100             self._parsed = self.value
 101
 102     def parse_trial(self) -> None:
 103         """
 104         Try alternate parsing methods.
 105         :return:
 106         """
 107         parts = []
 108         for c in self.value:
 109             pass
 110
 111
 112 class EnvironmentValues:
 113     """
 114     A class to hold all the environment variables
 115     """
 116     def __init__(self, **kw) -> None:
 117         self._dict = {}
 118         for k in kw:
 119             self._dict[k] = EnvironmentValue(kw[k])