/brz/remove-bazaar

# 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 io import BytesIO

from . import (

    tree,

    )

from .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, path, file_id=None):

        chunks = self.backing_tree.get_file_lines(path, file_id)

        filters = self.filter_stack_callback(path)

        context = ContentFilterContext(path, self)

        contents = filtered_output_bytes(chunks, filters, context)

        content = b''.join(contents)

        return content

    def get_file(self, path, file_id=None):

        return BytesIO(self.get_file_text(path, file_id))

    def has_filename(self, filename):

        return self.backing_tree.has_filename

    def is_executable(self, path, file_id=None):

        return self.backing_tree.is_executable(path, file_id)

    def iter_entries_by_dir(self, specific_files=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_files=specific_files)

    def lock_read(self):

        return self.backing_tree.lock_read()

    def unlock(self):

        return self.backing_tree.unlock()