dropsync

#!/usr/bin/env perl -w

##############################################################################
# File   : dropsync
# Author : Guillaume-Jean Herbiet  <guillaume-jean@herbiet.net>
#
#
# Copyright (c) 2009 Guillaume-Jean Herbiet     (http://herbiet.net)
#
# 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/>.
#
# Guillaume-Jean Herbiet
# <guillaume-jean@herbiet.net>
#
##############################################################################
use strict;
use warnings;

#-----------------------------------------------------------------------------
# Load aditional packages
#
use Getopt::Long;					# To easily retrieve arguments from command-line
use Term::ANSIColor qw(:constants);	# Colored output for the terminal
use YAML;							# To parse the config file
use Data::Dumper;					# Dump data structues (mainly used for debug)
use File::Basename;					# To easily manipulate files and paths
use File::Copy "cp";				# Easily copy files while keeping permissions
use File::Path qw(make_path);		# To easily create required path if necessary
use File::Compare;					# To compare file content

#-----------------------------------------------------------------------------

#-----------------------------------------------------------------------------
# Log and debug
#
sub say 	{ print @_, "\n"; }
sub ohai	{ say BOLD, BLUE,	"==> ", RESET, @_;}
sub oops	{ say BOLD, YELLOW,	"/!\\ ",RESET, @_;}
sub fail	{ say BOLD, RED,	"!!! ", RESET, @_;}

#-----------------------------------------------------------------------------

#-----------------------------------------------------------------------------
# Global variables
#
my %OPTIONS;						# Hash of passed options
my $OPTIONS_VALID;					# Are the passed options valid ?
my @ARGS = @ARGV;					# Array of passed options
my $COMMAND = `basename $0`;		# Name of the script
chomp($COMMAND);
my $VERSION = "0.3";				# Version of this script

#
# Generic variables
#
my $VERBOSE = 0;					# Verbose mode
my $DEBUG = 0;						# Debug mode
my $UNSAFE = 0;						# Run in unsafe mode
my $FORCED_PUSH = 0;				# Force pushing to dropsync
my $FORCED_RETRIEVE = 0;			# Force retrieve from dropsync

#
# Script specific variables
#
my $config_file = $ENV{'HOME'}."/.dropsyncrc.yaml";	# Default location of config file
my $config;											# Hashref of the config options

my $dropbox_location = $ENV{'HOME'}."/Dropbox";		# DropBox folder location
my $dropsync_folder = "dropsync";					# dropsync folder name

#-----------------------------------------------------------------------------

#-----------------------------------------------------------------------------
# Get passed arguments and check for validity.
#
$OPTIONS_VALID = GetOptions(
	\%OPTIONS,
	'help|h'	 => sub { USAGE(); },
	'version'	 => sub { VERSION_MESSAGE(); },
	'verbose|v+' => \$VERBOSE,
	'debug|d'	 => sub { $VERBOSE = 1; $DEBUG = 1; },
	'config-file|f=s' => \$config_file,
	'unsafe+'			 => \$UNSAFE,
	'force-push|p+'		 => \$FORCED_PUSH,
	'force-retrieve|r+'	 => \$FORCED_RETRIEVE
);

unless ($OPTIONS_VALID) {
	fail "Error in arguments.";
	USAGE(1);
}

sub USAGE {
	my $exitval = defined($_) ? $_ : 0;
	print <<EOF;
$COMMAND [-h|--help] [--version] [--verbose|-v] [--debug|-d]
    [--config-file|-f <path to config file>] [--unsafe]

    --help, -h          : Print this help, then exit
    --version           : Print the script version, then exit
    --verbose, -v       : Enable verbose mode
    --debug, -d         : Enable debug mode

    --config-file, -f   : Alternate location for the configuration file
                          (Default: \$HOME/.dropsyncrc.yaml)

    --force-push, -p    : Force pushing local files to the dropsync folder,
                          whatever the conflict resolution status.
    --force-retrieve, -r: Force retrieving local files from the dropsync folder,
                          whatever the conflict resolution status.

    --unsafe            : When run in unsafe mode, no backup of conflicting
                          files will be kept.
                          (This mode is not recommanded and disabled by default).
EOF
	exit $exitval;
}

sub VERSION_MESSAGE {
	say "This is ", BOLD, "$COMMAND", RESET, " v$VERSION.";
	print <<EOF;
Copyright (c) 2010 Guillaume-Jean Herbiet  (http://herbiet.net)
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
EOF
	exit 0;
}

#-----------------------------------------------------------------------------

#-----------------------------------------------------------------------------
# Core code
#

#
# Read configuration from the specified file
$config = read_config_file($config_file);
#

#
# dropsync folder location management
#
my $src_folder = setup_src_folder();

#
# Files backup/update
#
ohai "Syncing selected files." if $VERBOSE;
for my $file (@{$config->{'files'}}) {

	if (-f $ENV{'HOME'}."/".$file && ! -f $src_folder."/".$file) {
		say CYAN, "$file", RESET, " requires to be put in dropsync." if $VERBOSE;
		safe_copy($ENV{'HOME'}."/".$file, $src_folder."/".$file);
	}
	elsif (	-f $src_folder."/".$file && ! -f $ENV{'HOME'}."/".$file) {
		say CYAN, "$file", RESET, " requires to be pulled from dropsync." if $VERBOSE;
		safe_copy($src_folder."/".$file, $ENV{'HOME'}."/".$file);
	}
	elsif (	-f $src_folder."/".$file && -f $ENV{'HOME'}."/".$file) {
		say CYAN, "$file", RESET, " exists in both your file system and in dropsync." if $VERBOSE;
		fix_conflict($file);
	}
	elsif ( ! -f $src_folder."/".$file && ! -e $ENV{'HOME'}."/".$file) {
		oops CYAN, "$file", RESET, " exits neither in your file system nor in dropsync and will be ignored.";
	}
	else {
		oops CYAN, "$file", RESET, " did not match any sync case managed by dropsync and will be ignored.";
	}
}

#-----------------------------------------------------------------------------

#-----------------------------------------------------------------------------
# Additional functions
#
sub read_config_file {
	my $file = shift;
	
	# Try to open the configuration file or die
	unless (-f $file) {
		fail "Configuration file $file does not exist!"; exit 2;
	} elsif ($VERBOSE) { ohai "Reading configuration from $file."; }

	# Read the configuration to a hash
	# NOTE: config_array and config_string should be empty
	my ($config_hash, $config_array, $config_string) = YAML::LoadFile($file);
	ohai "Read configuration:\n", Dumper($config_hash, $config_array, $config_string) if $DEBUG;
	oops "Some unnamed variables were found while reading config file $_. They will be ignored."
		if (defined $config_array || defined $config_string);
	return $config_hash;
}

sub setup_src_folder {
	# Update the location of the Dropbox location
	# and the dropsync folder if required
	$dropbox_location = $config->{'dropbox_location'}
		if (exists $config->{'dropbox_location'} && !$config->{'dropbox_location'} eq "");
	$dropsync_folder = $config->{'dropsync_folder'}
		if (exists $config->{'dropsync_folder'} && !$config->{'dropsync_folder'} eq "");

	# Create the dropsync folder if required
	my $src = $dropbox_location."/".$dropsync_folder;
	unless (-d $src) {
		mkdir $src;
		ohai "Creating non-existing dropsync folder at $src."
			if $VERBOSE;
	}
	say "Using ", YELLOW, "$src", RESET, " as source folder." if $VERBOSE;
	return $src;
}

#
# File manipulation functions
#

sub fix_conflict {
	my $filepath = shift;
	
	# Read the last modification time, the newest wins
	my $lastmod_fs = $FORCED_RETRIEVE ? 0 : (stat $ENV{'HOME'}."/".$filepath)[9];
	my $lastmod_ds = $FORCED_PUSH ? 0 : (stat $src_folder."/".$filepath)[9];
	
	if (compare($ENV{'HOME'}."/".$filepath, $src_folder."/".$filepath) == 0) {
		say "  - Files are identical, nothing will be changed." if $DEBUG;
	}
	elsif ($lastmod_fs > $lastmod_ds && cleanup_file($src_folder."/".$filepath)) {
		say "  - Updating file in dropsync using $ENV{'HOME'}/$filepath" if $DEBUG;
		#move_to_dropsync_and_link($filepath);
		safe_copy($ENV{'HOME'}."/".$filepath, $src_folder."/".$filepath);
	}
	elsif ($lastmod_fs < $lastmod_ds && cleanup_file($ENV{'HOME'}."/".$filepath)) {
		say "  - Updating file in file system using $src_folder/$filepath" if $DEBUG;
		safe_copy($src_folder."/".$filepath, $ENV{'HOME'}."/".$filepath);
	}
	else {
		oops "Conflict on $ENV{'HOME'}."/".$filepath was not resolved. This file will not updated.";
	}
}

sub safe_copy {
	my ($src, $dest) = @_;
	unless (-f $src) {
		oops "  - Source file $src does not exist.";
		return 0;
	}
	elsif (	-f $dest) {
		oops "  - Destination file $dest already exists";
		return 0;
	}
	elsif (	create_path_if_required($dest) && cp $src, $dest) {
		say "  - Copy $src to $dest" if $DEBUG;
		return 1;
	}
	else {
		oops "Error in copying $src to $dest: $!";
		return 0;
	}
}

sub create_path_if_required {
	my $filepath = shift;
	my $path = dirname($filepath);
	if (-d $path) {
		say "  - Required path $path already exists, no need to create" if $DEBUG;
		return 1;
	}
	elsif (make_path($path)) {
		say "  - Created required path $path" if $DEBUG;
		return 1;
	}
	else {
		oops "Error in creating required path $path: $!";
		return 0;
	}
}

sub cleanup_file {
	my $path = shift;
	if ($UNSAFE && !unlink $path) {
		oops "Error in deleting old version of $path: $!";
		oops "Further fixing will be ignored.";
		return 0;
	}
	elsif (!$UNSAFE && !rename $path, $path.".ds_".time) {
		oops "Error in saving old version of $path: $!";
		oops "Further fixing will be ignored.";
		return 0;
	}
	return 1;
}

#-----------------------------------------------------------------------------