Remove memcached support

Apparently we had memcached support. It was never worth it, and put
a weird md5 hash calculation in the path of regular caching. Seeing
as it was completely undocumented, I doubt anyone has ever used it.

overviewer.py

@@ -455,8 +455,6 @@ dir but you forgot to put quotes around the directory, since it contains spaces.
     # Set up the cache objects to use
     caches = []
     caches.append(cache.LRUCache(size=100))
-    if config.get("memcached_host", False):
-        caches.append(cache.Memcached(config['memcached_host']))
     # TODO: optionally more caching layers here
 
     renders = config['renders']

overviewer_core/cache.py

@@ -22,7 +22,6 @@ attribute.
 """
 import functools
 import logging
-import cPickle
 
 class LRUCache(object):
     """A simple, generic, in-memory LRU cache that implements the standard
@@ -137,31 +136,3 @@ class LRUCache(object):
         d = self.destructor
         if d:
             d(link.value)
-
-# memcached is an option, but unless your IO costs are really high, it just
-# ends up adding overhead and isn't worth it.
-try:
-    import memcache
-except ImportError:
-    class Memcached(object):
-        def __init__(*args):
-            raise ImportError("No module 'memcache' found. Please install python-memcached")
-else:
-    class Memcached(object):
-        def __init__(self, conn='127.0.0.1:11211'):
-            self.conn = conn
-            self.mc = memcache.Client([conn], debug=0, pickler=cPickle.Pickler, unpickler=cPickle.Unpickler)
-
-        def __getstate__(self):
-            return self.conn
-        def __setstate__(self, conn):
-            self.__init__(conn)
-
-        def __getitem__(self, key):
-            v = self.mc.get(key)
-            if not v:
-                raise KeyError()
-            return v
-
-        def __setitem__(self, key, value):
-            self.mc.set(key, value)

overviewer_core/settingsDefinition.py

@@ -103,10 +103,6 @@ outputdir = Setting(required=True, validator=validateOutputDir, default=None)
 
 processes = Setting(required=True, validator=int, default=-1)
 
-# memcached is an option, but unless your IO costs are really high, it just
-# ends up adding overhead and isn't worth it.
-memcached_host = Setting(required=False, validator=str, default=None)
-
 # TODO clean up this ugly in sys.argv hack
 if platform.system() == 'Windows' or not sys.stdout.isatty() or "--simple" in sys.argv:
     obs = LoggingObserver()

overviewer_core/world.py

@@ -731,7 +731,7 @@ class CachedRegionSet(RegionSetWrapper):
         self.key = s
 
     def get_chunk(self, x, z):
-        key = hashlib.md5(repr((self.key, x, z))).hexdigest()
+        key = (self.key, x, z)
         for i, cache in enumerate(self.caches):
             try:
                 retval = cache[key]