/brz/remove-bazaar

# Copyright (C) 2008 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

"""View management.

Views are contained within a working tree and normally constructed 

when first accessed.  Clients should do, for example, ...

  tree.views.lookup_view()

"""

import re

from bzrlib import (

    errors,

    )

_VIEWS_FORMAT_MARKER_RE = re.compile(r'Bazaar views format (\d+)')

_VIEWS_FORMAT1_MARKER = "Bazaar views format 1\n"

class _Views(object):

    """Base class for View managers."""

    def supports_views(self):

        raise NotImplementedError(self.supports_views)

class PathBasedViews(_Views):

    """View storage in an unversioned tree control file.

    Views are stored in terms of paths relative to the tree root.

    The top line of the control file is a format marker in the format:

      Bazaar views format X

    where X is an integer number. Version 1 format is stored as follows:

     * the line after the format marker holds the name of the current view

     * subsequent lines hold view definitions, one per line is the format

       name file1 file2 ...

    where the fields are separated by a nul character (\0). The views file

    is encoded in utf-8.

    """

    def __init__(self, tree):

        self.tree = tree

        self._loaded = False

        self._current = None

        self._views = {}

    def supports_views(self):

        return True

    def get_view_info(self):

        """Get the current view and dictionary of views.

        :return: current, views where

          current = the name of the current view or None if no view is enabled

          views = a map from view name to list of files/directories

        """

        self._load_view_info()

        return self._current, self._views

    def set_view_info(self, current, views):

        """Set the current view and dictionary of views.

        :param current: the name of the current view or None if no view is

          enabled

        :param views: a map from view name to list of files/directories

        """

        if current is not None and current not in views:

            raise errors.NoSuchView(current)

        self.tree.lock_write()

        try:

            self._current = current

            self._views = views

            self._save_view_info()

        finally:

            self.tree.unlock()

    def lookup_view(self, view_name=None):

        """Return the contents of a view.

        :param view_Name: name of the view or None to lookup the current view

        :return: the list of files/directories in the requested view

        """

        self._load_view_info()

        try:

            if view_name is None:

                if self._current:

                    view_name = self._current

                else:

                    return []

            return self._views[view_name]

        except KeyError:

            raise errors.NoSuchView(view_name)

    def set_view(self, view_name, view_files, make_current=True):

        """Add or update a view definition.

        :param view_name: the name of the view

        :param view_files: the list of files/directories in the view

        :param make_current: make this view the current one or not

        """

        self.tree.lock_write()

        try:

            self._load_view_info()

            self._views[view_name] = view_files

            if make_current:

                self._current = view_name

            self._save_view_info()

        finally:

            self.tree.unlock()

    def delete_view(self, view_name):

        """Delete a view definition.

        If the view deleted is the current one, the current view is reset.

        """

        self.tree.lock_write()

        try:

            self._load_view_info()

            try:

                del self._views[view_name]

            except KeyError:

                raise errors.NoSuchView(view_name)

            if view_name == self._current:

                self._current = None

            self._save_view_info()

        finally:

            self.tree.unlock()

    def _save_view_info(self):

        """Save the current view and all view definitions.

        Be sure to have initialised self._current and self._views before

        calling this method.

        """

        self.tree.lock_write()

        try:

            self.tree._transport.put_bytes('views',

                self._serialize_view_content(self._current, self._views))

        finally:

            self.tree.unlock()

    def _load_view_info(self):

        """Load the current view and dictionary of view definitions."""

        if not self._loaded:

            self.tree.lock_read()

            try:

                try:

                    view_content = self.tree._transport.get_bytes('views')

                except errors.NoSuchFile, e:

                    self._current, self._views = None, {}

                else:

                    self._current, self._views = \

                        self._deserialize_view_content(view_content)

            finally:

                self.tree.unlock()

            self._loaded = True

    def _serialize_view_content(self, current, view_dict):

        """Convert a current view and view dictionary into a stream."""

        lines = [_VIEWS_FORMAT1_MARKER]

        if current is None:

            lines.append("\n")

        else:

            lines.append((current + "\n").encode('utf-8'))

        for view in sorted(view_dict):

            view_data = "%s\0%s\n" % (view, "\0".join(view_dict[view]))

            lines.append(view_data.encode('utf-8'))

        return "".join(lines)

    def _deserialize_view_content(self, view_content):

        """Convert a stream into a current view and dictionary of views."""

        # as a special case to make initialization easy, an empty definition

        # maps to no current view and an empty view dictionary

        if view_content == '':

            return None, {}

        lines = view_content.splitlines()

        match = _VIEWS_FORMAT_MARKER_RE.match(lines[0])

        if not match:

            raise ValueError(

                "format marker missing from top of views file")

        elif match.group(1) != '1':

            raise ValueError(

                "cannot decode views format %s" % match.group(1))

        try:

            current = lines[1].decode('utf-8')

            if current == '':

                current = None

            views = {}

            for line in lines[2:]:

                parts = line.decode('utf-8').split('\0')

                view = parts.pop(0)

                views[view] = parts

            return current, views

        except ValueError, e:

            raise ValueError("failed to deserialize views content %r: %s"

                % (view_content, e))

class DisabledViews(_Views):

    """View storage that refuses to store anything.

    This is used by older formats that can't store views.

    """

    def __init__(self, tree):

        self.tree = tree

    def supports_views(self):

        return False

    def _not_supported(self, *a, **k):

        raise errors.ViewsNotSupported(self.tree)

    get_view_info = _not_supported

    set_view_info = _not_supported

    lookup_view = _not_supported

    set_view = _not_supported

    delete_view = _not_supported