Pulling in latest software construction toolkit.

site_scons/site_tools/component_bits.py

 #!/usr/bin/python2.4
 # Copyright 2008, Google Inc.
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
@@ skipping 17 matching lines @@
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 """Environment bit support for software construction toolkit.
 
 This module is automatically included by the component_setup tool.
 """
 
 
 import __builtin__
+import types
 import SCons
 
 
 _bit_descriptions = {}
 _bits_with_options = set()
 _bit_exclusive_groups = {}
 
 #------------------------------------------------------------------------------
 
 
-def DeclareBit(bit_name, desc, exclusive_groups=tuple()):
+def _CheckDeclared(bits):
+  """Checks each of the bits to make sure it's been declared.
+
+  Args:
+    bits: List of bits to check.
+
+  Raises:
+    ValueError: A bit has not been declared.
+  """
+  for bit in bits:
+    if bit not in _bit_descriptions:
+      raise ValueError('Bit "%s" used before DeclareBit()' %
+                       bit)
+
+
+def _CheckExclusive(already_set, proposed):
+  """Checks if setting proposed bits would violate any exclusive groups.
+
+  Args:
+    already_set: List of bits already set.
+    proposed: List of bits attempting to be set.
+
+  Raises:
+    ValueError: A proposed bit belongs to an exclusive group which already has
+        a bit set.
+  """
+  # Remove any already-set bits from proposed (note this makes a copy of
+  # proposed so we don't alter the passed list).
+  proposed = [bit for bit in proposed if bit not in already_set]
+
+  for group_name, group_bits in _bit_exclusive_groups.items():
+    set_match = group_bits.intersection(already_set)
+    proposed_match = group_bits.intersection(proposed)
+    if set_match and proposed_match:
+      raise ValueError('Unable to set bit "%s" because it belongs to the same '
+                       'exclusive group "%s" as already-set bit "%s"' % (
+                       proposed_match.pop(), group_name, set_match.pop()))
+
+
+#------------------------------------------------------------------------------
+
+
+def DeclareBit(bit_name, desc, exclusive_groups=None):
   """Declares and describes the bit.
 
   Args:
     bit_name: Name of the bit being described.
     desc: Description of bit.
     exclusive_groups: Bit groups which this bit belongs to.  At most one bit
-        may be set in each exclusive group.
+        may be set in each exclusive group.  May be a string, list of string,
+        or None.
 
   Raises:
     ValueError: The bit has already been defined with a different description,
         or the description is empty.
 
   Adds a description for the bit in the global dictionary of bit names.  All
   bits should be described before being used in Bit()/AllBits()/AnyBits().
   """
 
   if not desc:
     raise ValueError('Must supply a description for bit "%s"' % bit_name)
 
   existing_desc = _bit_descriptions.get(bit_name)
   if existing_desc and desc != existing_desc:
     raise ValueError('Cannot describe bit "%s" as "%s" because it has already'
                      'been described as "%s".' %
                      (bit_name, desc, existing_desc))
 
   _bit_descriptions[bit_name] = desc
 
   # Add bit to its exclusive groups
-  for g in exclusive_groups:
-    if g not in _bit_exclusive_groups:
-      _bit_exclusive_groups[g] = set()
-    _bit_exclusive_groups[g].add(bit_name)
+  if exclusive_groups:
+    if type(exclusive_groups) == types.StringType:
+      exclusive_groups = [exclusive_groups]
+    for g in exclusive_groups:
+      if g not in _bit_exclusive_groups:
+        _bit_exclusive_groups[g] = set()
+      _bit_exclusive_groups[g].add(bit_name)
 
 #------------------------------------------------------------------------------
 
-
 def Bit(env, bit_name):
   """Checks if the environment has the bit.
 
   Args:
     env: Environment to check.
     bit_name: Name of the bit to check.
 
   Returns:
     True if the bit is present in the environment.
   """
-  # TODO(rspangler): Add bit sanity checking (description exists, exclusive
-  # groups not violated).
+  _CheckDeclared([bit_name])
   return bit_name in env['_BITS']
 
 #------------------------------------------------------------------------------
 
 
 def AllBits(env, *args):
   """Checks if the environment has all the bits.
 
   Args:
     env: Environment to check.
     args: List of bit names to check.
 
   Returns:
     True if every bit listed is present in the environment.
   """
-  # TODO(rspangler): Add bit sanity checking
+  _CheckDeclared(args)
   return set(args).issubset(env['_BITS'])
 
 #------------------------------------------------------------------------------
 
 
 def AnyBits(env, *args):
   """Checks if the environment has at least one of the bits.
 
   Args:
     env: Environment to check.
     args: List of bit names to check.
 
   Returns:
     True if at least one bit listed is present in the environment.
   """
-  # TODO(rspangler): Add bit sanity checking
+  _CheckDeclared(args)
   return set(args).intersection(env['_BITS'])
 
 #------------------------------------------------------------------------------
 
 
 def SetBits(env, *args):
   """Sets the bits in the environment.
 
   Args:
     env: Environment to check.
     args: List of bit names to set.
   """
-  # TODO(rspangler): Add bit sanity checking
+  _CheckDeclared(args)
+  _CheckExclusive(env['_BITS'], args)
   env['_BITS'] = env['_BITS'].union(args)
 
 #------------------------------------------------------------------------------
 
 
 def ClearBits(env, *args):
   """Sets the bits in the environment.
 
   Args:
     env: Environment to check.
     args: List of bit names to set.
   """
-  # TODO(rspangler): Add bit sanity checking
+  _CheckDeclared(args)
   env['_BITS'] = env['_BITS'].difference(args)
 
 #------------------------------------------------------------------------------
 
 
 def SetBitFromOption(env, bit_name, default):
   """Sets the bit in the environment from a command line option.
 
   Args:
     env: Environment to check.
     bit_name: Name of the bit to set from a command line option.
     default: Default value for bit if command line option is not present.
   """
-  # TODO(rspangler): Add bit sanity checking
+  _CheckDeclared([bit_name])
 
   # Add the command line option, if not already present
   if bit_name not in _bits_with_options:
     _bits_with_options.add(bit_name)
     SCons.Script.AddOption('--' + bit_name,
                            dest=bit_name,
                            action='store_true',
                            help='set bit:' + _bit_descriptions[bit_name])
     SCons.Script.AddOption('--no-' + bit_name,
                            dest=bit_name,
@@ skipping 24 matching lines @@
 
   # Add methods to environment
   env.AddMethod(AllBits)
   env.AddMethod(AnyBits)
   env.AddMethod(Bit)
   env.AddMethod(ClearBits)
   env.AddMethod(SetBitFromOption)
   env.AddMethod(SetBits)
 
   env['_BITS'] = set()