GHI-#9 Implement the core plugin "Clean(snowsaw.Plugin)"

snowsaw/plugins/clean.py

@@ -0,0 +1,63 @@
+import snowsaw
+import os
+
+
+class Clean(snowsaw.Plugin):
+    """
+    Core plugin to clean 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("Core plugin \"Clean\" cannot handle the directive \"{}\"".format(directive))
+        return self._process_clean(data)
+
+    def _process_clean(self, targets):
+        """
+        Processes specified targets.
+
+        :param targets: The targets to process
+        :return: True if the targets have been processed successfully
+        """
+        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 successfully cleaned")
+        return success
+
+    def _clean(self, target):
+        """
+        Cleans all broken symbolic links in the specified target that point to a subdirectory of the snowblocks directory.
+
+        :param target: The target to clean
+        :return: True if cleaned successfully
+        """
+        if not os.path.isdir(os.path.expanduser(target)):
+            self._log.debug("Ignoring nonexistent directory {}".format(target))
+            return True
+        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._context.snowblock_dir()):
+                    self._log.lowinfo("Removing invalid link {} -> {}".format(path, os.path.join(os.path.dirname(path), os.readlink(path))))
+                    os.remove(path)
+        return True
+
+    def _in_directory(self, path, directory):
+        """
+        Checks if the specified path is in the directory.
+
+        :param path: The path to check
+        :param directory: The directory to get checked
+        :return: 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