/stdhome

# conflict.py

#

# Copyright (C) 2013 to 2014 Tim Marston <tim@edm.am>

#

# This file is part of stdhome (hereafter referred to as "this program").

# See http://ed.am/dev/stdhome for more information.

#

# 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 3 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, see <http://www.gnu.org/licenses/>.

import filecmp, os

from .walker import Walker

import stdhome.the as the

class ConflictWalker( Walker ):

	"""The conflict walker traverses the repo looking for "deployment conflicts"

	(i.e., changes in the type of file).  This is run prior to running the

	copy-out walker and, as such, is given a list of files that were copied-in

	and which is can, therefore, safely ignore.  It can also be given a list of

	files affected by the update (it will walk all repo files otherwise).

	Walker source:       repo

	Walker destination:  home dir

	Walker traversing:   repo

	"""

	def __init__( self, ignore_files, walk_files = None ):

		self.src_dir = the.repo.full_dir

		self.dst_dir = the.full_home_dir

		self.walk_list = walk_files if walk_files is not None else \

						 self.generate_walk_list( the.repo.full_dir )

		self.ignore_files = ignore_files

		self.changed = list()

		self.obstructed = list()

	def process( self, rel_file, src, dst ):

		# if entity is missing in home dir, it's ok to copy out (and there's no

		# need to recurse)

		if dst.type == '_': return False

		# if entity was copied-in, it's ok to copy out

		elif rel_file in self.ignore_files:

			# we recurse only if this is a directory in the home dir, because if

			# it isn't copying-out will replace whatever's in the home dir with

			# the whole directory from the repo

			return dst.type == 'd'

		# entity has changed type?

		elif src.get_type_name() != dst.get_type_name():

			self.changed.append( "%s (%s => %s)" % (

				rel_file, src.get_type_name(), dst.get_type_name() ) )

			# if an entity has changed to/from a directory, we don't care about

			# anything that directory does/did contain

			return False

		# entity is a file (that wasn't copyied-in)?

		elif dst.type == 'f':

			# only a problem if its content is different

			if not filecmp.cmp( src.file, dst.file ):

				self.obstructed.append( rel_file )

				return False

		# entity is a symlink (that wasn't copied-in)?

		if dst.type == 'l':

			# only a problem if the symlink is different

			if os.readlink( src.file ) != os.readlink( dst.file ):

				self.obstructed.append( rel_file )

				return False

		# nothing to see here

		return True