From c9fbf9f2d389162525ea6f8f0781c62f6dbb6bc0 Mon Sep 17 00:00:00 2001
From: helmutm <helmutm@fd906abe-77d9-0310-91a1-e0d9ade77398>
Date: Wed, 22 Nov 2006 14:46:01 +0000
Subject: [PATCH] MultiKeyDict re-implemented

git-svn-id: svn://svn.cy55.de/Zope3/src/cybertools/trunk@1517 fd906abe-77d9-0310-91a1-e0d9ade77398
---
 index/multikey.py | 34 ++++++++++++++++------------------
 1 file changed, 16 insertions(+), 18 deletions(-)

diff --git a/index/multikey.py b/index/multikey.py
index 68b0e7f..a882251 100644
--- a/index/multikey.py
+++ b/index/multikey.py
@@ -28,8 +28,8 @@ class MultiKeyDict(dict):
 
     def __init__(self, keylen=None, **kw):
         super(MultiKeyDict, self).__init__(**kw)
+        self.submapping = {}
         self.keylen = keylen
-        self.data = {}
 
     def __setitem__(self, key, value):
         assert type(key) is tuple
@@ -37,11 +37,10 @@ class MultiKeyDict(dict):
             self.keylen = len(key)
         assert len(key) == self.keylen
         k0 = key[0]
-        sub = None
         if len(key) > 1:
-            sub = MultiKeyDict(self.keylen-1)
+            sub = self.submapping.setdefault(k0, MultiKeyDict(self.keylen-1))
             sub[key[1:]] = value
-        self.data[k0] = MultiKeyDictEntry(value, sub)
+        super(MultiKeyDict, self).__setitem__(k0, value)
 
     def __getitem__(self, key):
         r = self.get(key, _not_found)
@@ -54,21 +53,26 @@ class MultiKeyDict(dict):
         assert len(key) == self.keylen
         k0 = key[0]
         rsub = _not_found
-        r0 = self.data.get(k0, _not_found)
+        r0 = super(MultiKeyDict, self).get(k0, _not_found)
         if r0 is _not_found:
             r0 = self.getFallback(k0)
         if r0 is _not_found:
             return default
         if len(key) > 1:
-            sub = r0.submapping
-            rsub = sub.get(key[1:], _not_found)
-            if rsub is _not_found:
-                return default      # !!! leads to backtracking !!!
-            return rsub
-        return rsub is _not_found and r0.value or rsub
+            sub = self.submapping.get(k0, _not_found)
+            if sub is _not_found:
+                sub = self.getSubmappingFallback(key)
+            if sub is _not_found:
+                rsub = _not_found
+            else:
+                rsub = sub.get(key[1:], _not_found)
+                if rsub is _not_found:
+                    return default
+        result = rsub is _not_found and r0 or rsub
+        return result is _not_found and default or result
 
     def getFallback(self, key):
-        return self.data.get(None, _not_found)
+        return super(MultiKeyDict, self).get(None, _not_found)
 
     def getSubmappingFallback(self, key):
         return self.submapping.get(None, _not_found)
@@ -77,9 +81,3 @@ class MultiKeyDict(dict):
         return ('<MultiKeyDict %s; submapping: %s>'
                 % (super(MultiKeyDict, self).__repr__(), `self.submapping`))
 
-
-class MultiKeyDictEntry(object):
-
-    def __init__(self, value, submapping):
-        self.value = value
-        self.submapping = submapping