circular_dependency: use itertools.product()

Python's cartesian product function does exactly what we want, so use
it to simplify our code.

diff --git a/pym/_emerge/resolver/circular_dependency.py b/pym/_emerge/resolver/circular_dependency.py
index 17898012e7533fbd87c3b86fe868ba26653baec4..9a3286c5c9556edfa21464c3c6bb6f6acd04e916 100644 (file)
--- a/pym/_emerge/resolver/circular_dependency.py
+++ b/pym/_emerge/resolver/circular_dependency.py
@@ -3,7 +3,7 @@
 
 from __future__ import print_function
 
-from itertools import chain
+from itertools import chain, product
 
 from portage.dep import use_reduce, extract_affecting_use, check_required_use, get_required_use_flags
 from portage.exception import InvalidDependString
@@ -147,27 +147,9 @@ class circular_dependency_handler(object):
                        #We iterate over all possible settings of these use flags and gather
                        #a set of possible changes
                        #TODO: Use the information encoded in REQUIRED_USE
-                       use_state = []
-                       for flag in affecting_use:
-                               use_state.append("disabled")
-
-                       def _next_use_state(state, id=None):
-                               if id is None:
-                                       id = len(state)-1
-
-                               if id == 0 and state[0] == "enabled":
-                                       return False
-
-                               if state[id] == "disabled":
-                                       state[id] = "enabled"
-                                       for i in range(id+1,len(state)):
-                                               state[i] = "disabled"
-                                       return True
-                               else:
-                                       return _next_use_state(state, id-1)
-
                        solutions = set()
-                       while(True):
+                       for use_state in product(("disabled", "enabled"),
+                               repeat=len(affecting_use)):
                                current_use = set(self.depgraph._pkg_use_enabled(parent))
                                for flag, state in zip(affecting_use, use_state):
                                        if state == "enabled":
@@ -200,9 +182,6 @@ class circular_dependency_handler(object):
                                                                solution.add((flag, False))
                                                solutions.add(frozenset(solution))
 
-                               if not _next_use_state(use_state):
-                                       break
-
                        for solution in solutions:
                                ignore_solution = False
                                for other_solution in solutions: