From 75a7b7605b82945a8701f34df414da98411afd52 Mon Sep 17 00:00:00 2001
From: Jakub Warmuz <jakub@warmuz.org>
Date: Sat, 9 May 2015 07:25:36 +0000
Subject: [PATCH] PluginsRegistry.find_init

---
 letsencrypt/client/plugins/disco.py      | 26 ++++++++++++++++++++++++
 letsencrypt/client/plugins/disco_test.py |  6 ++++++
 2 files changed, 32 insertions(+)

diff --git a/letsencrypt/client/plugins/disco.py b/letsencrypt/client/plugins/disco.py
index f4a9faecf..fd636d59a 100644
--- a/letsencrypt/client/plugins/disco.py
+++ b/letsencrypt/client/plugins/disco.py
@@ -16,6 +16,9 @@ class PluginEntryPoint(object):
     PREFIX_FREE_DISTRIBUTIONS = ["letsencrypt"]
     """Distributions for which prefix will be omitted."""
 
+    # this object is mutable, don't allow it to be hashed!
+    __hash__ = None
+
     def __init__(self, entry_point):
         self.name = self.entry_point_to_plugin_name(entry_point)
         self.plugin_cls = entry_point.load()
@@ -188,6 +191,29 @@ class PluginsRegistry(collections.Mapping):
         return self.filter(lambda p_ep: p_ep.available)
         # succefully prepared + misconfigured
 
+    def find_init(self, plugin):
+        """Find an initialized plugin.
+
+        This is particularly useful for finding a name for the plugin
+        (although `.IPluginFactory.__call__` takes ``name`` as one of
+        the arguments, ``IPlugin.name`` is not part of the interface)::
+
+          # plugin is an instance providing IPlugin, initialized
+          # somewhere else in the code
+          plugin_registry.find_init(plugin).name
+
+        Returns ``None`` if ``plugin`` is not found in the registry.
+
+        """
+        # use list instead of set beacse PluginEntryPoint is not hashable
+        candidates = [plugin_ep for plugin_ep in self.plugins.itervalues()
+                      if plugin_ep.initialized and plugin_ep.init() is plugin]
+        assert len(candidates) <= 1
+        if candidates:
+            return candidates[0]
+        else:
+            return None
+
     def __repr__(self):
         return "{0}({1!r})".format(
             self.__class__.__name__, set(self.plugins.itervalues()))
diff --git a/letsencrypt/client/plugins/disco_test.py b/letsencrypt/client/plugins/disco_test.py
index 945f72d6b..ca3bc42d4 100644
--- a/letsencrypt/client/plugins/disco_test.py
+++ b/letsencrypt/client/plugins/disco_test.py
@@ -216,6 +216,12 @@ class PluginsRegistryTest(unittest.TestCase):
         self.plugin_ep.available = False
         self.assertEqual({}, self.reg.available().plugins)
 
+    def test_find_init(self):
+        self.assertTrue(self.reg.find_init(mock.Mock()) is None)
+        self.plugin_ep.initalized = True
+        self.assertTrue(
+            self.reg.find_init(self.plugin_ep.init()) is self.plugin_ep)
+
     def test_repr(self):
         self.plugin_ep.__repr__ = lambda _: "PluginEntryPoint#mock"
         self.assertEqual("PluginsRegistry(set([PluginEntryPoint#mock]))",