1 files changed, 77 insertions, 0 deletions
diff --git a/bzrlib/filter_tree.py b/bzrlib/filter_tree.py
new file mode 100644
index 0000000..8fcb867
--- /dev/null
+++ b/bzrlib/filter_tree.py
@@ -0,0 +1,77 @@
+# Copyright (C) 2011 Canonical Ltd
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+
+"""Content-filtered view of any tree.
+"""
+
+from __future__ import absolute_import
+
+from bzrlib import (
+    tree,
+    )
+from bzrlib.filters import (
+    ContentFilterContext,
+    filtered_output_bytes,
+    )
+
+
+class ContentFilterTree(tree.Tree):
+    """A virtual tree that applies content filters to an underlying tree.
+    
+    Not every operation is supported yet.
+    """
+
+    def __init__(self, backing_tree, filter_stack_callback):
+        """Construct a new filtered tree view.
+
+        :param filter_stack_callback: A callable taking a path that returns
+            the filter stack that should be used for that path.
+        :param backing_tree: An underlying tree to wrap.
+        """
+        self.backing_tree = backing_tree
+        self.filter_stack_callback = filter_stack_callback
+
+    def get_file_text(self, file_id, path=None):
+        chunks = self.backing_tree.get_file_lines(file_id, path)
+        filters = self.filter_stack_callback(path)
+        if path is None:
+            path = self.backing_tree.id2path(file_id)
+        context = ContentFilterContext(path, self, None)
+        contents = filtered_output_bytes(chunks, filters, context)
+        content = ''.join(contents)
+        return content
+
+    def has_filename(self, filename):
+        return self.backing_tree.has_filename
+
+    def is_executable(self, file_id, path=None):
+        return self.backing_tree.is_executable(file_id, path)
+
+    def iter_entries_by_dir(self, specific_file_ids=None, yield_parents=None):
+        # NB: This simply returns the parent tree's entries; the length may be
+        # wrong but it can't easily be calculated without filtering the whole
+        # text.  Currently all callers cope with this; perhaps they should be
+        # updated to a narrower interface that only provides things guaranteed
+        # cheaply available across all trees. -- mbp 20110705
+        return self.backing_tree.iter_entries_by_dir(
+            specific_file_ids=specific_file_ids,
+            yield_parents=yield_parents)
+
+    def lock_read(self):
+        return self.backing_tree.lock_read()
+
+    def unlock(self):
+        return self.backing_tree.unlock()