Move common libs to libs/common

libs/common/subliminal/extensions.py

@@ -0,0 +1,106 @@
+# -*- coding: utf-8 -*-
+from pkg_resources import EntryPoint
+
+from stevedore import ExtensionManager
+
+
+class RegistrableExtensionManager(ExtensionManager):
+    """:class:~stevedore.extensions.ExtensionManager` with support for registration.
+
+    It allows loading of internal extensions without setup and registering/unregistering additional extensions.
+
+    Loading is done in this order:
+
+    * Entry point extensions
+    * Internal extensions
+    * Registered extensions
+
+    :param str namespace: namespace argument for :class:~stevedore.extensions.ExtensionManager`.
+    :param list internal_extensions: internal extensions to use with entry point syntax.
+    :param \*\*kwargs: additional parameters for the :class:~stevedore.extensions.ExtensionManager` constructor.
+
+    """
+    def __init__(self, namespace, internal_extensions, **kwargs):
+        #: Registered extensions with entry point syntax
+        self.registered_extensions = []
+
+        #: Internal extensions with entry point syntax
+        self.internal_extensions = internal_extensions
+
+        super(RegistrableExtensionManager, self).__init__(namespace, **kwargs)
+
+    def _find_entry_points(self, namespace):
+        # copy of default extensions
+        eps = list(super(RegistrableExtensionManager, self)._find_entry_points(namespace))
+
+        # internal extensions
+        for iep in self.internal_extensions:
+            ep = EntryPoint.parse(iep)
+            if ep.name not in [e.name for e in eps]:
+                eps.append(ep)
+
+        # registered extensions
+        for rep in self.registered_extensions:
+            ep = EntryPoint.parse(rep)
+            if ep.name not in [e.name for e in eps]:
+                eps.append(ep)
+
+        return eps
+
+    def register(self, entry_point):
+        """Register an extension
+
+        :param str entry_point: extension to register (entry point syntax).
+        :raise: ValueError if already registered.
+
+        """
+        if entry_point in self.registered_extensions:
+            raise ValueError('Extension already registered')
+
+        ep = EntryPoint.parse(entry_point)
+        if ep.name in self.names():
+            raise ValueError('An extension with the same name already exist')
+
+        ext = self._load_one_plugin(ep, False, (), {}, False)
+        self.extensions.append(ext)
+        if self._extensions_by_name is not None:
+            self._extensions_by_name[ext.name] = ext
+        self.registered_extensions.insert(0, entry_point)
+
+    def unregister(self, entry_point):
+        """Unregister a provider
+
+        :param str entry_point: provider to unregister (entry point syntax).
+
+        """
+        if entry_point not in self.registered_extensions:
+            raise ValueError('Extension not registered')
+
+        ep = EntryPoint.parse(entry_point)
+        self.registered_extensions.remove(entry_point)
+        if self._extensions_by_name is not None:
+            del self._extensions_by_name[ep.name]
+        for i, ext in enumerate(self.extensions):
+            if ext.name == ep.name:
+                del self.extensions[i]
+                break
+
+
+#: Provider manager
+provider_manager = RegistrableExtensionManager('subliminal.providers', [
+    'addic7ed = subliminal.providers.addic7ed:Addic7edProvider',
+    'legendastv = subliminal.providers.legendastv:LegendasTVProvider',
+    'opensubtitles = subliminal.providers.opensubtitles:OpenSubtitlesProvider',
+    'podnapisi = subliminal.providers.podnapisi:PodnapisiProvider',
+    'shooter = subliminal.providers.shooter:ShooterProvider',
+    'subscenter = subliminal.providers.subscenter:SubsCenterProvider',
+    'thesubdb = subliminal.providers.thesubdb:TheSubDBProvider',
+    'tvsubtitles = subliminal.providers.tvsubtitles:TVsubtitlesProvider'
+])
+
+#: Refiner manager
+refiner_manager = RegistrableExtensionManager('subliminal.refiners', [
+    'metadata = subliminal.refiners.metadata:refine',
+    'omdb = subliminal.refiners.omdb:refine',
+    'tvdb = subliminal.refiners.tvdb:refine'
+])