#!/usr/bin/env bash
#
# files - functions acting on files.
#
# Copyright 2015 - 2019 Einhard Leichtfuß
#
# This file is part of rsync-backup.
#
# rsync-backup is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published
# by the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# rsync-backup 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 Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with rsync-backup.  If not, see <https://www.gnu.org/licenses/>.
#


# Create directory, unless it exists already.  Returns non-zero, if the
# named file exists however is not a directory.
#
# $1: directory: path
#
function create_dir
{
	local dir="$1"

	if [[ ! -e "$dir" && ! -L "$dir" ]]
	then
		mkdir "$dir" || return $RET_ERROR
	elif [[ ! -d "$dir" || -L "$dir" ]]
	then
		error "\"$dir\" is not a directory."
		return $RET_FILE_ERR
	fi

	return $RET_SUCCESS
}


# Create a new directory, assuring it did not exist before.
#
# $1: directory: path
#
function create_new_dir
{
	local dir="$1"

	if [[ -e "$dir" || -L "$dir" ]]
	then
		error "\"$dir\" exists already."
		return $RET_FILE_ERR
	fi

	mkdir "$dir" || return $RET_ERROR

	return $RET_SUCCESS
}


# Verify the specified file is a directory.
#
# $1: directory: path
#
function assert_is_dir
{
	local dir="$1"

	if [[ ! -d "$dir" || -L "$dir" ]]
	then
		error "\"$dir\" is not a directory."
		return $RET_FILE_ERR
	fi

	return $RET_SUCCESS
}


# Replace symbolic link $2 by symbolic link $1.  $2 may not exist.
#
# $1: source file name: path
# $2: target file name: path
#
function replace_symlink
{
	local src="$1"
	local tgt="$2"

	if [[ ! -L "$src" ]]
	then
		error "\"$src\" is not a symbolic link."
		return $RET_FILE_ERR
	fi

	if [[ ! -L "$tgt" && -e "$tgt" ]]
	then
		error "\"$tgt\" is not a symbolic link."
		return $RET_FILE_ERR
	fi

	mv -T "$src" "$tgt" || return $RET_ERROR

	return $RET_SUCCESS
}


# Replace symbolic link $1's target by $2.  $1 may not exist.
#
# $1: link file: path
# $2: link target: path
#
function replace_symlink_target
{
	local link="$1"
	local tgt="$2"

	if [[ ! -L "$link" && -e "$link" ]]
	then
		error "\"$link\" is not a symbolic link."
		return $RET_FILE_ERR
	fi

	ln -sfT "$tgt" "$link" || return $RET_ERROR

	return $RET_SUCCESS
}


# Remove a symbolic link.
#
# $1: link: path
#
function remove_symlink
{
	local file="$1"

	if [[ ! -L "$file" ]]
	then
		error "\"$file\" is not a symbolic link."
		return $RET_FILE_ERR
	fi

	rm "$file" || return $RET_ERROR

	return $RET_SUCCESS
}

# vi: ft=bash ts=2 sw=2 noet