SCons/Node/Alias.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 """Alias nodes.
  25
  26 This creates a hash of global Aliases (dummy targets).
  27 """
  28
  29 import collections
  30
  31 import SCons.Errors
  32 import SCons.Node
  33 import SCons.Util
  34 from SCons.Util import hash_signature
  35
  36 class AliasNameSpace(collections.UserDict):
  37     def Alias(self, name, **kw):
  38         if isinstance(name, SCons.Node.Alias.Alias):
  39             return name
  40         try:
  41             a = self[name]
  42         except KeyError:
  43             a = SCons.Node.Alias.Alias(name, **kw)
  44             self[name] = a
  45         return a
  46
  47     def lookup(self, name, **kw):
  48         try:
  49             return self[name]
  50         except KeyError:
  51             return None
  52
  53 class AliasNodeInfo(SCons.Node.NodeInfoBase):
  54     __slots__ = ('csig',)
  55     current_version_id = 2
  56     field_list = ['csig']
  57     def str_to_node(self, s):
  58         return default_ans.Alias(s)
  59
  60     def __getstate__(self):
  61         """
  62         Return all fields that shall be pickled. Walk the slots in the class
  63         hierarchy and add those to the state dictionary. If a '__dict__' slot is
  64         available, copy all entries to the dictionary. Also include the version
  65         id, which is fixed for all instances of a class.
  66         """
  67         state = getattr(self, '__dict__', {}).copy()
  68         for obj in type(self).mro():
  69             for name in getattr(obj,'__slots__',()):
  70                 if hasattr(self, name):
  71                     state[name] = getattr(self, name)
  72
  73         state['_version_id'] = self.current_version_id
  74         try:
  75             del state['__weakref__']
  76         except KeyError:
  77             pass
  78
  79         return state
  80
  81     def __setstate__(self, state) -> None:
  82         """
  83         Restore the attributes from a pickled state.
  84         """
  85         # TODO check or discard version
  86         del state['_version_id']
  87         for key, value in state.items():
  88             if key not in ('__weakref__',):
  89                 setattr(self, key, value)
  90
  91
  92 class AliasBuildInfo(SCons.Node.BuildInfoBase):
  93     __slots__ = ()
  94     current_version_id = 2
  95
  96 class Alias(SCons.Node.Node):
  97
  98     NodeInfo = AliasNodeInfo
  99     BuildInfo = AliasBuildInfo
 100
 101     def __init__(self, name) -> None:
 102         super().__init__()
 103         self.name = name
 104         self.changed_since_last_build = 1
 105         self.store_info = 0
 106
 107     def str_for_display(self):
 108         return '"' + self.__str__() + '"'
 109
 110     def __str__(self) -> str:
 111         return self.name
 112
 113     def make_ready(self) -> None:
 114         self.get_csig()
 115
 116     really_build = SCons.Node.Node.build
 117     is_up_to_date = SCons.Node.Node.children_are_up_to_date
 118
 119     def is_under(self, dir) -> bool:
 120         # Make Alias nodes get built regardless of
 121         # what directory scons was run from. Alias nodes
 122         # are outside the filesystem:
 123         return True
 124
 125     def get_contents(self):
 126         """The contents of an alias is the concatenation
 127         of the content signatures of all its sources."""
 128         childsigs = [n.get_csig() for n in self.children()]
 129         return ''.join(childsigs)
 130
 131     def sconsign(self) -> None:
 132         """An Alias is not recorded in .sconsign files"""
 133         pass
 134
 135     #
 136     #
 137     #
 138
 139     def build(self) -> None:
 140         """A "builder" for aliases."""
 141         pass
 142
 143     def convert(self) -> None:
 144         try: del self.builder
 145         except AttributeError: pass
 146         self.reset_executor()
 147         self.build = self.really_build
 148
 149     def get_csig(self):
 150         """
 151         Generate a node's content signature, the digested signature
 152         of its content.
 153
 154         node - the node
 155         cache - alternate node to use for the signature cache
 156         returns - the content signature
 157         """
 158         try:
 159             return self.ninfo.csig
 160         except AttributeError:
 161             pass
 162
 163         contents = self.get_contents()
 164         csig = hash_signature(contents)
 165         self.get_ninfo().csig = csig
 166         return csig
 167
 168 default_ans = AliasNameSpace()
 169
 170 SCons.Node.arg2nodes_lookups.append(default_ans.lookup)
 171
 172 # Local Variables:
 173 # tab-width:4
 174 # indent-tabs-mode:nil
 175 # End:
 176 # vim: set expandtab tabstop=4 shiftwidth=4: