From 3fd91222c6fb46bc2d5838229d7c54130619d73a Mon Sep 17 00:00:00 2001
From: Chris McDonough <chrism@agendaless.com>
Date: Sun, 13 Jul 2008 10:21:59 +0000
Subject: Use an application-local component registry.

---
 repoze/bfg/registry.py | 70 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 70 insertions(+)
 create mode 100644 repoze/bfg/registry.py

(limited to 'repoze/bfg/registry.py')

diff --git a/repoze/bfg/registry.py b/repoze/bfg/registry.py
new file mode 100644
index 000000000..acb5a4abc
--- /dev/null
+++ b/repoze/bfg/registry.py
@@ -0,0 +1,70 @@
+import threading
+import zope.component
+
+from zope.component import getGlobalSiteManager
+from zope.component.interfaces import ComponentLookupError
+from zope.component.interfaces import IComponentLookup
+from zope.component.registry import Components
+from zope.component import getSiteManager as original_getSiteManager
+
+from zope.configuration import xmlconfig
+
+class ThreadLocalRegistryManager(threading.local):
+    registry = getGlobalSiteManager()
+    def set(self, registry):
+        self.registry = registry
+
+    def get(self):
+        return self.registry
+
+    def clear(self):
+        self.registry = getGlobalSiteManager()
+
+registry_manager = ThreadLocalRegistryManager()
+
+def setRegistryManager(manager): # for unit tests
+    global registry_manager
+    old_registry_manager = registry_manager
+    registry_manager = manager
+    return old_registry_manager
+
+def makeRegistry(filename, package, lock=threading.Lock()):
+    # This is absurd and probably not worth it.  We want to try to
+    # push our ZCML-defined configuration into an app-local component
+    # registry in order to allow more than one bfg app to live in the
+    # same process space without one unnecessarily stomping on the
+    # other's component registrations (although I suspect directives
+    # that side effects are going to fail).  The only way to do that
+    # currently is to override zope.component.getGlobalSiteManager for
+    # the duration of the ZCML includes.  We acquire a lock in case
+    # another make_app runs in a different thread simultaneously, in a
+    # vain attempt to prevent mixing of registrations.  There's not
+    # much we can do about non-make_app code that tries to use the
+    # global site manager API directly in a different thread while we
+    # hold the lock.  Those registrations will end up in our
+    # application's registry.
+    lock.acquire()
+    try:
+        # Do I actually want a globalregistry.BaseGlobalComponents?
+        registry = Components(package.__name__)
+        registry_manager.set(registry)
+        original_getSiteManager.sethook(getSiteManager)
+        zope.component.getGlobalSiteManager = registry_manager.get
+        context = xmlconfig.file(filename, package=package)
+        return context, registry
+    finally:
+        lock.release()
+        zope.component.getGlobalSiteManager = getGlobalSiteManager
+        registry_manager.clear()
+
+def getSiteManager(context=None):
+    if context is None:
+        return registry_manager.get()
+    else:
+        try:
+            return IComponentLookup(context)
+        except TypeError, error:
+            raise ComponentLookupError(*error.args)
+
+from zope.testing.cleanup import addCleanUp
+addCleanUp(original_getSiteManager.reset)
-- 
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