From: Mike Bayer <mike_mp@zzzcomputing.com>
Date: Tue, 6 Apr 2010 17:20:31 +0000 (-0400)
Subject: - EdgeCollection can now go away
X-Git-Tag: rel_0_6_0~45
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=57335697c6a0f629561ed8fe084687a0f847b0c8;p=thirdparty%2Fsqlalchemy%2Fsqlalchemy.git

- EdgeCollection can now go away
- fix reflection test
---

diff --git a/lib/sqlalchemy/topological.py b/lib/sqlalchemy/topological.py
index 07b1ba03e4..fbde7c6014 100644
--- a/lib/sqlalchemy/topological.py
+++ b/lib/sqlalchemy/topological.py
@@ -10,46 +10,26 @@ from sqlalchemy.exc import CircularDependencyError
 from sqlalchemy import util
 
 
-__all__ = ['sort']
-
-class _EdgeCollection(object):
-    """A collection of directed edges."""
-
-    def __init__(self, edges):
-        self.parent_to_children = util.defaultdict(set)
-        self.child_to_parents = util.defaultdict(set)
-        for parentnode, childnode in edges:
-            self.parent_to_children[parentnode].add(childnode)
-            self.child_to_parents[childnode].add(parentnode)
-            
-    def outgoing(self, node):
-        return self.parent_to_children[node]
-    
-    def incoming(self, node):
-        return self.child_to_parents[node]
-        
-    def __iter__(self):
-        for parent in self.parent_to_children:
-            for child in self.outgoing(parent):
-                yield (parent, child)
-
-    def __repr__(self):
-        return repr(list(self))
+__all__ = ['sort', 'sort_as_subsets', 'find_cycles']
 
 def sort_as_subsets(tuples, allitems):
     output = set()
 
     todo = set(allitems)
-    edges = _EdgeCollection(tuples)
+
+    edges = util.defaultdict(set)
+    for parent, child in tuples:
+        edges[child].add(parent)
+    
     while todo:
         for node in list(todo):
-            if not todo.intersection(edges.incoming(node)):
+            if not todo.intersection(edges[node]):
                 output.add(node)
 
         if not output:
             raise CircularDependencyError(
-                    "Circular dependency detected: cycles: %r all edges: %r" % 
-                    (find_cycles(tuples, allitems), edges))
+                    "Circular dependency detected: cycles: %r all edges: %s" % 
+                    (find_cycles(tuples, allitems), _dump_edges(edges, True)))
 
         todo.difference_update(output)
         yield output
@@ -68,7 +48,10 @@ def sort(tuples, allitems):
 def find_cycles(tuples, allitems):
     # straight from gvr with some mods
     todo = set(allitems)
-    edges = _EdgeCollection(tuples)
+
+    edges = util.defaultdict(set)
+    for parent, child in tuples:
+        edges[parent].add(child)
 
     output = set()
     
@@ -77,7 +60,7 @@ def find_cycles(tuples, allitems):
         stack = [node]
         while stack:
             top = stack[-1]
-            for node in edges.outgoing(top):
+            for node in edges[top]:
                 if node in stack:
                     cyc = stack[stack.index(node):]
                     todo.difference_update(cyc)
@@ -91,3 +74,14 @@ def find_cycles(tuples, allitems):
                 node = stack.pop()
     return output
 
+def _dump_edges(edges, reverse):
+    l = []
+    for left in edges:
+        for right in edges[left]:
+            if reverse:
+                l.append((right, left))
+            else:
+                l.append((left, right))
+    return repr(l)
+
+
diff --git a/test/engine/test_reflection.py b/test/engine/test_reflection.py
index bf94cce657..18074337f2 100644
--- a/test/engine/test_reflection.py
+++ b/test/engine/test_reflection.py
@@ -742,7 +742,12 @@ class CreateDropTest(TestBase):
     def test_sorter( self ):
         tables = metadata.sorted_tables
         table_names = [t.name for t in tables]
-        self.assert_( table_names == ['users', 'orders', 'items', 'email_addresses'] or table_names ==  ['users', 'email_addresses', 'orders', 'items'])
+        ua = [n for n in table_names if n in ('users', 'email_addresses')]
+        oi = [n for n in table_names if n in ('orders', 'items')]
+        
+        eq_(ua, ['users', 'email_addresses'])
+        eq_(oi, ['orders', 'items'])
+        
 
     def testcheckfirst(self):
         try: