Add a first run at a plugin system

terminatorlib/plugin.py

@@ -0,0 +1,59 @@
+#!/usr/bin/python
+# Terminator by Chris Jones <cmsj@tenshu.net>
+# GPL v2 only
+"""plugin.py - Base plugin system"""
+
+import sys
+import os
+import borg
+from util import dbg
+
+class Plugin(object):
+    """Definition of our base plugin class"""
+    capabilities = None
+
+    def __init__(self):
+        """Class initialiser."""
+        pass
+
+class PluginRegistry(borg.Borg):
+    """Definition of a class to store plugin instances"""
+    instances = None
+    path = None
+
+    def __init__(self):
+        """Class initialiser"""
+        borg.Borg.__init__(self)
+        self.prepare_attributes()
+
+    def prepare_attributes(self):
+        """Prepare our attributes"""
+        if not self.instances:
+            self.instances = {}
+        if not self.path:
+            (head, tail) = os.path.split(borg.__file__)
+            self.path = os.path.join(head, 'plugins')
+            dbg('PluginRegistry::prepare_attributes: Plugin path: %s' % 
+                self.path)
+
+    def load_plugins(self):
+        """Load all plugins present in the plugins/ directory in our module"""
+        sys.path.insert(0, self.path)
+        files = os.listdir(self.path)
+        for plugin in files:
+            if os.path.isfile(os.path.join(self.path, plugin)) and \
+               plugin[-3:] == '.py':
+                dbg('PluginRegistry::load_plugins: Importing plugin %s' % 
+                    plugin)
+                __import__(plugin[:-3], None, None, [''])
+
+    def get_plugins_by_capability(self, capability):
+        """Return a list of plugins with a particular capability"""
+        result = []
+        for plugin in Plugin.__subclasses__():
+            if capability in plugin.capabilities:
+                if not plugin in self.instances:
+                    self.instances[plugin] = plugin()
+                result.append(self.instances[plugin])
+        return result
+