plugin: reduce code duplication

Factor out supported directive checking, drop redundant checking in
handle().

5 files changed, 6 insertions, 37 deletions

diff --git a/dotbot/plugin.py b/dotbot/plugin.py
index 56d4da8..5e2c923 100644
--- a/dotbot/plugin.py
+++ b/dotbot/plugin.py
@@ -6,6 +6,8 @@ class Plugin(object):
     Abstract base class for commands that process directives.
     '''
 
+    _directive = None
+
     def __init__(self, context):
         self._context = context
         self._log = Messenger()
@@ -14,7 +16,7 @@ class Plugin(object):
         '''
         Returns true if the Plugin can handle the directive.
         '''
-        raise NotImplementedError
+        return directive == self._directive
 
     def handle(self, directive, data):
         '''
diff --git a/dotbot/plugins/clean.py b/dotbot/plugins/clean.py
index e7f1561..c8f3a03 100644
--- a/dotbot/plugins/clean.py
+++ b/dotbot/plugins/clean.py
@@ -9,15 +9,7 @@ class Clean(dotbot.Plugin):
 
     _directive = 'clean'
 
-    def can_handle(self, directive):
-        return directive == self._directive
-
-    def handle(self, directive, data):
-        if directive != self._directive:
-            raise ValueError('Clean cannot handle directive %s' % directive)
-        return self._process_clean(data)
-
-    def _process_clean(self, targets):
+    def handle(self, directive, targets):
         success = True
         defaults = self._context.defaults().get(self._directive, {})
         for target in targets:
diff --git a/dotbot/plugins/create.py b/dotbot/plugins/create.py
index 7e39c1a..2420558 100644
--- a/dotbot/plugins/create.py
+++ b/dotbot/plugins/create.py
@@ -9,15 +9,7 @@ class Create(dotbot.Plugin):
 
     _directive = 'create'
 
-    def can_handle(self, directive):
-        return directive == self._directive
-
-    def handle(self, directive, data):
-        if directive != self._directive:
-            raise ValueError('Create cannot handle directive %s' % directive)
-        return self._process_paths(data)
-
-    def _process_paths(self, paths):
+    def handle(self, directive, paths):
         success = True
         for path in paths:
             path = os.path.expandvars(os.path.expanduser(path))
diff --git a/dotbot/plugins/link.py b/dotbot/plugins/link.py
index 4112fe5..1064bb6 100644
--- a/dotbot/plugins/link.py
+++ b/dotbot/plugins/link.py
@@ -13,15 +13,7 @@ class Link(dotbot.Plugin):
 
     _directive = 'link'
 
-    def can_handle(self, directive):
-        return directive == self._directive
-
-    def handle(self, directive, data):
-        if directive != self._directive:
-            raise ValueError('Link cannot handle directive %s' % directive)
-        return self._process_links(data)
-
-    def _process_links(self, links):
+    def handle(self, directive, links):
         success = True
         defaults = self._context.defaults().get('link', {})
         for destination, source in links.items():
diff --git a/dotbot/plugins/shell.py b/dotbot/plugins/shell.py
index 6fe79b8..f0121e6 100644
--- a/dotbot/plugins/shell.py
+++ b/dotbot/plugins/shell.py
@@ -11,16 +11,7 @@ class Shell(dotbot.Plugin):
 
     _directive = 'shell'
 
-    def can_handle(self, directive):
-        return directive == self._directive
-
     def handle(self, directive, data):
-        if directive != self._directive:
-            raise ValueError('Shell cannot handle directive %s' %
-                directive)
-        return self._process_commands(data)
-
-    def _process_commands(self, data):
         success = True
         defaults = self._context.defaults().get('shell', {})
         for item in data: