# Copyright (c) 2017 The NetBSD Foundation, Inc.
# All rights reserved.
#
# This code is derived from software contributed to The NetBSD Foundation
# by Johnny C. Lam.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
# ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
# TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
# PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
# BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
#
# NAME
#	preremove.subr -- pre-removal actions for packages
#
# SYNOPSIS
#	task_preremove <datafile>
#
# DESCRIPTION
#	The task_preremove function performs actions that MUST occur BEFORE
#	deleting the package files for the removal to be successful:
#
#	    o Unregister GNU info files.
#	    o Remove GTK+ icon theme caches.
#	    o Remove unmodified configuration files.
#
#	The datafile contains lines of the form:
#
#	    # <keyword>: <arg> ...
#
#	These lines are used as input to the various script functions.
#
# RETURN VALUES
#	Returns 0 on success, and >0 if an error occurs.
#
# ENVIRONMENT
#	The following variables are used if they are set:
#
#	TASK_VERBOSE
#		List of package tasks that should emit verbose output.
#		If ${TASK_VERBOSE} is "all", then all tasks are verbose.
#		If ${TASK_VERBOSE} is "none", then no tasks are verbose.
#		Otherwise, if one of the tasks is "default", then the
#		default list of tasks are verbose.
#

__task_preremove__="yes"

task_load files
task_load icon_themes
task_load info_files
task_load sort
task_load taskfunc

task_preremove()
{
	: ${TASK_VERBOSE:=default}

	[ $# -gt 0 ] || return 127
	local datafile="$1"; shift

	[ -f "$datafile" ] || return 1

	local stage="preremove"

	# $verbose are the package tasks that give verbose output.
	# Expand "all", "default" and "none" to a fixed list of tasks.
	#
	local verbose="${TASK_VERBOSE}"
	case " $verbose " in
	" all ")
		verbose="files function icon_themes info_files" ;;
	*" default "*)
		# These tasks are verbose by default since they touch
		# system files and directories.
		#
		verbose="files function" ;;
	" none ")
		verbose= ;;
	esac

	local silent

	# Unregistering a GNU info files requires reading the file to find
	# all nodes listed in the file, so it must be done before the file
	# is removed.  Any errors in unregistering GNU info files are
	# non-fatal.
	#
	case " $verbose " in
	*" info_files "*)
		silent= ;;
	*)	silent="-s" ;;
	esac
	task_info_files $silent remove $stage < $datafile

	# GTK+ icon theme caches exist in the package installation
	# directory, so they must be removed before their packages can be
	# successfully removed.  Any errors in removing icon caches are
	# non-fatal.
	#
	case " $verbose " in
	*" icon_themes "*)
		silent= ;;
	*)	silent="-s" ;;
	esac
	task_icon_themes $silent remove $stage < $datafile

	# Removing a configuration file requires comparing it to the
	# example file from which it was copied, so it must be done before
	# the example file is removed.  Any errors in removing
	# configuration files are non-fatal.
	#
	case " $verbose " in
	*" files "*)
		silent= ;;
	*)	silent="-s" ;;
	esac
	task_files $silent remove $stage < $datafile

	# Run the generic package tasks.
	case " $verbose " in
	*" function "*)
		silent= ;;
	*)	silent="-s" ;;
	esac
	if task_sort -r < $datafile | task_function $silent remove $stage; then
		: "success"
	else
		# Errors from the generic package tasks are fatal.
		return 1
	fi

	return 0
}