From 971903dfd2cb3a5843091f56600d6d3174bd19a4 Mon Sep 17 00:00:00 2001
From: Fabio Niephaus <code@fniephaus.com>
Date: Mon, 13 Mar 2017 13:41:44 +0100
Subject: [PATCH] Move Cell to cells.py and cache QuasiConstants

---
 rsqueakvm/objspace.py                      |  4 +--
 rsqueakvm/plugins/misc_primitive_plugin.py |  9 +------
 rsqueakvm/plugins/socket_plugin.py         |  8 +-----
 rsqueakvm/util/cells.py                    | 29 +++++++++++++++++++---
 4 files changed, 29 insertions(+), 21 deletions(-)

diff --git a/rsqueakvm/objspace.py b/rsqueakvm/objspace.py
index 17c08c06..eda79788 100644
--- a/rsqueakvm/objspace.py
+++ b/rsqueakvm/objspace.py
@@ -52,9 +52,9 @@ def __init__(self):
         self.altf4quit = QuasiConstant(False)
 
         from rsqueakvm.display import NullDisplay
-        self._display = QuasiConstant(None, type=NullDisplay)
+        self._display = QuasiConstant(None, cls=NullDisplay)
         from rsqueakvm.interpreter import Interpreter
-        self.interp = QuasiConstant(None, type=Interpreter)
+        self.interp = QuasiConstant(None, cls=Interpreter)
 
         self.make_special_objects()
         self.strategy_factory = storage.StrategyFactory(self)
diff --git a/rsqueakvm/plugins/misc_primitive_plugin.py b/rsqueakvm/plugins/misc_primitive_plugin.py
index 2104cd0d..240c48bb 100644
--- a/rsqueakvm/plugins/misc_primitive_plugin.py
+++ b/rsqueakvm/plugins/misc_primitive_plugin.py
@@ -2,19 +2,12 @@
 from rsqueakvm.error import PrimitiveFailedError
 from rsqueakvm.model.variable import W_BytesObject
 from rsqueakvm.plugins.plugin import Plugin
+from rsqueakvm.util.cells import Cell
 
 from rpython.rlib.rarithmetic import r_uint, intmask
 from rpython.rlib import jit
 
 
-class Cell(object):
-    _attrs_ = ["value"]
-    _immutable_fields_ = ["value?"]
-    def __init__(self, value): self.value = value
-    def set(self, v): self.value = v
-    def get(self): return self.value
-
-
 class MiscPrimitivePlugin(Plugin):
     _attrs_ = ["ascii_order"]
     _immutable_fields_ = ["ascii_order"]
diff --git a/rsqueakvm/plugins/socket_plugin.py b/rsqueakvm/plugins/socket_plugin.py
index 93c7b6ba..e2347fa8 100644
--- a/rsqueakvm/plugins/socket_plugin.py
+++ b/rsqueakvm/plugins/socket_plugin.py
@@ -1,10 +1,10 @@
 import errno
-import sys
 
 from rsqueakvm import error
 from rsqueakvm.model.base import W_AbstractObjectWithIdentityHash
 from rsqueakvm.model.variable import W_BytesObject
 from rsqueakvm.plugins.plugin import Plugin
+from rsqueakvm.util.cells import Cell
 from rsqueakvm.util.system import IS_SHELL, IS_WINDOWS
 
 from rpython.rlib import rsocket, _rsocket_rffi, objectmodel
@@ -23,12 +23,6 @@ def non_blocking_recv(self, count):
         return self.socket.recv(count, _rsocket_rffi.MSG_DONTWAIT)
 
 
-class Cell(object):
-    _attrs_ = ["value"]
-    def __init__(self, value): self.value = value
-    def set(self, v): self.value = v
-    def get(self): return self.value
-
 ResolverUninitialized = 0
 ResolverReady = 1
 ResolverBusy = 2
diff --git a/rsqueakvm/util/cells.py b/rsqueakvm/util/cells.py
index e8897af8..50bc51df 100644
--- a/rsqueakvm/util/cells.py
+++ b/rsqueakvm/util/cells.py
@@ -1,9 +1,20 @@
 from rpython.rlib import jit
+from rpython.rlib.cache import Cache
 from rpython.rlib.objectmodel import specialize, import_from_mixin
 
 from rsqueakvm.util.version import Version
 
 
+class QuasiConstantCache(Cache):
+    def _build(self, obj):
+        class NewQuasiConst(object):
+            import_from_mixin(QuasiConstantMixin)
+        return NewQuasiConst
+
+
+cache = QuasiConstantCache()
+
+
 class QuasiConstantMixin(object):
     """Mixin for constant values that can be edited, but will be promoted
     to a constant when jitting."""
@@ -28,9 +39,19 @@ def changed(self):
         self.set(Version())
 
 
+@specialize.memo()
+def QuasiConstant(initial_value, cls=None):
+    if cls is not None:
+        return cache.getorbuild(cls)(initial_value)
+    return cache.getorbuild(type(initial_value))(initial_value)
+
+
 @specialize.arg(1)
 @specialize.argtype(0)
-def QuasiConstant(initial_value, type=object):
-    class NewQuasiConst(object):
-        import_from_mixin(QuasiConstantMixin)
-    return NewQuasiConst(initial_value)
+def Cell(initial_value, type=object):
+    class NewCell(object):
+        _attrs_ = ["value"]
+        def __init__(self, value): self.value = value
+        def set(self, v): self.value = v
+        def get(self): return self.value
+    return NewCell(initial_value)