[pypy-commit] pypy set-strategies: added fastpath for initialization of lists with iterables using int- or stringstrategy

[l.diekmann]

Author: Lukas Diekmann <lukas.diekmann at uni-duesseldorf.de>
Branch: set-strategies
Changeset: r51221:29acb5e48ac9
Date: 2012-01-11 14:09 +0100
http://bitbucket.org/pypy/pypy/changeset/29acb5e48ac9/

Log:	added fastpath for initialization of lists with iterables using int-
	or stringstrategy

diff --git a/pypy/objspace/std/listobject.py b/pypy/objspace/std/listobject.py
--- a/pypy/objspace/std/listobject.py
+++ b/pypy/objspace/std/listobject.py
@@ -1042,6 +1042,21 @@
         elif isinstance(w_iterable, W_TupleObject):
             W_ListObject(space, w_iterable.wrappeditems[:]).copy_into(w_list)
             return
+
+        intlist = space.listview_int(w_iterable)
+        if intlist is not None:
+            w_list.strategy = strategy = space.fromcache(IntegerListStrategy)
+             # need to copy because intlist can share with w_iterable
+            w_list.lstorage = strategy.erase(intlist[:])
+            return
+
+        strlist = space.listview_str(w_iterable)
+        if strlist is not None:
+            w_list.strategy = strategy = space.fromcache(StringListStrategy)
+             # need to copy because intlist can share with w_iterable
+            w_list.lstorage = strategy.erase(strlist[:])
+            return
+
         w_list.__init__(space, [])
         # xxx special hack for speed
         from pypy.interpreter.generator import GeneratorIterator
diff --git a/pypy/objspace/std/test/test_liststrategies.py b/pypy/objspace/std/test/test_liststrategies.py
--- a/pypy/objspace/std/test/test_liststrategies.py
+++ b/pypy/objspace/std/test/test_liststrategies.py
@@ -463,6 +463,34 @@
         w_res = listobject.list_pop__List_ANY(space, w_l, space.w_None) # does not crash
         assert space.unwrap(w_res) == 3
 
+    def test_create_list_from_set(self):
+        from pypy.objspace.std.setobject import W_SetObject
+        from pypy.objspace.std.setobject import _initialize_set
+
+        space = self.space
+        w = space.wrap
+
+        w_l = W_ListObject(space, [space.wrap(1), space.wrap(2), space.wrap(3)])
+
+        w_set = W_SetObject(self.space)
+        _initialize_set(self.space, w_set, w_l)
+        w_set.iter = None # make sure fast path is used
+
+        w_l2 = W_ListObject(space, [])
+        space.call_method(w_l2, "__init__", w_set)
+
+        w_l2.sort(False)
+        assert space.eq_w(w_l, w_l2)
+
+        w_l = W_ListObject(space, [space.wrap("a"), space.wrap("b"), space.wrap("c")])
+        _initialize_set(self.space, w_set, w_l)
+
+        space.call_method(w_l2, "__init__", w_set)
+
+        w_l2.sort(False)
+        assert space.eq_w(w_l, w_l2)
+
+
 
 class TestW_ListStrategiesDisabled:
     def setup_class(cls):