Add Cleaner executor

2 files changed, 50 insertions, 0 deletions

diff --git a/dotbot/executor/__init__.py b/dotbot/executor/__init__.py
index 1762f78..d87ca4b 100644
--- a/dotbot/executor/__init__.py
+++ b/dotbot/executor/__init__.py
@@ -1,3 +1,4 @@
 from .executor import Executor
 from .linker import Linker
+from .cleaner import Cleaner
 from .commandrunner import CommandRunner
diff --git a/dotbot/executor/cleaner.py b/dotbot/executor/cleaner.py
new file mode 100644
index 0000000..59b9259
--- /dev/null
+++ b/dotbot/executor/cleaner.py
@@ -0,0 +1,49 @@
+import os
+from . import Executor
+
+class Cleaner(Executor):
+    '''
+    Cleans broken symbolic links.
+    '''
+
+    _directive = 'clean'
+
+    def can_handle(self, directive):
+        return directive == self._directive
+
+    def handle(self, directive, data):
+        if directive != self._directive:
+            raise ValueError('Cleaner cannot handle directive %s' % directive)
+        return self._process_clean(data)
+
+    def _process_clean(self, targets):
+        success = True
+        for target in targets:
+            success &= self._clean(target)
+        if success:
+            self._log.info('All targets have been cleaned')
+        else:
+            self._log.error('Some targets were not succesfully cleaned')
+        return success
+
+    def _clean(self, target):
+        '''
+        Cleans all the broken symbolic links in target that point to
+        a subdirectory of the base directory.
+        '''
+        for item in os.listdir(os.path.expanduser(target)):
+            path = os.path.join(os.path.expanduser(target), item)
+            if not os.path.exists(path) and os.path.islink(path):
+                if self._in_directory(path, self._base_directory):
+                    self._log.lowinfo('Removing invalid link %s -> %s' %
+                        (path, os.path.join(os.path.dirname(path), os.readlink(path))))
+                    os.remove(path)
+        return True
+
+    def _in_directory(self, path, directory):
+        '''
+        Returns true if the path is in the directory.
+        '''
+        directory = os.path.join(os.path.realpath(directory), '')
+        path = os.path.realpath(path)
+        return os.path.commonprefix([path, directory]) == directory