# Copyright 2002 Ben Escoto
#
# This file is part of rdiff-backup.
#
# rdiff-backup 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, Inc., 675 Mass Ave, Cambridge MA
# 02139, USA; either version 2 of the License, or (at your option) any
# later version; incorporated herein by reference.

"""Parse args and setup connections

The functions in this module are used once by Main to parse file
descriptions like bescoto@folly.stanford.edu:/usr/bin/ls and to set up
the related connections.

"""

# This is the schema that determines how rdiff-backup will open a
# pipe to the remote system.  If the file is given as A::B, %s will
# be substituted with A in the schema.
__cmd_schema = 'ssh -C %s rdiff-backup --server'
__cmd_schema_no_compress = 'ssh %s rdiff-backup --server'

# This is a list of remote commands used to start the connections.
# The first is None because it is the local connection.
__conn_remote_cmds = [None]

class SetConnectionsException(Exception): pass

def get_cmd_pairs(arglist, remote_schema = None, remote_cmd = None):
	"""Map the given file descriptions into command pairs

	Command pairs are tuples cmdpair with length 2.  cmdpair[0] is
	None iff it describes a local path, and cmdpair[1] is the path.

	"""
	global __cmd_schema
	if remote_schema: __cmd_schema = remote_schema
	elif not Globals.ssh_compression: __cmd_schema = __cmd_schema_no_compress

	if not arglist: return []
	desc_pairs = map(parse_file_desc, arglist)

	if filter(lambda x: x[0], desc_pairs): # True if any host_info found
		if remote_cmd:
			Log.FatalError("The --remote-cmd flag is not compatible "
						   "with remote file descriptions.")
	elif remote_schema:
		Log("Remote schema option ignored - no remote file "
			"descriptions.", 2)
	cmdpairs = map(desc2cmd_pairs, desc_pairs)
	if remote_cmd: # last file description gets remote_cmd
		cmd_pairs[-1] = (remote_cmd, cmd_pairs[-1][1])
	return cmdpairs

def cmdpair2rp(cmd_pair):
	"""Return normalized RPath from cmd_pair (remote_cmd, filename)"""
	cmd, filename = cmd_pair
	if cmd: conn = init_connection(cmd)
	else: conn = Globals.local_connection
	return RPath(conn, filename).normalize()

def desc2cmd_pairs(desc_pair):
	"""Return pair (remote_cmd, filename) from desc_pair"""
	host_info, filename = desc_pair
	if not host_info: return (None, filename)
	else: return (fill_schema(host_info), filename)

def parse_file_desc(file_desc):
	"""Parse file description returning pair (host_info, filename)

	In other words, bescoto@folly.stanford.edu::/usr/bin/ls =>
	("bescoto@folly.stanford.edu", "/usr/bin/ls").  The
	complication is to allow for quoting of : by a \.  If the
	string is not separated by :, then the host_info is None.

	"""
	def check_len(i):
		if i >= len(file_desc):
			raise SetConnectionsException(
				"Unexpected end to file description %s" % file_desc)

	host_info_list, i, last_was_quoted = [], 0, None
	while 1:
		if i == len(file_desc):
			return (None, file_desc)

		if file_desc[i] == '\\':
			i = i+1
			check_len(i)
			last_was_quoted = 1
		elif (file_desc[i] == ":" and i > 0 and file_desc[i-1] == ":"
			  and not last_was_quoted):
			host_info_list.pop() # Remove last colon from name
			break
		else: last_was_quoted = None
		host_info_list.append(file_desc[i])
		i = i+1

	check_len(i+1)
	return ("".join(host_info_list), file_desc[i+1:])

def fill_schema(host_info):
	"""Fills host_info into the schema and returns remote command"""
	return __cmd_schema % host_info

def init_connection(remote_cmd):
	"""Run remote_cmd, register connection, and then return it

	If remote_cmd is None, then the local connection will be
	returned.  This also updates some settings on the remote side,
	like global settings, its connection number, and verbosity.

	"""
	if not remote_cmd: return Globals.local_connection

	Log("Executing " + remote_cmd, 4)
	stdin, stdout = os.popen2(remote_cmd)
	conn_number = len(Globals.connections)
	conn = PipeConnection(stdout, stdin, conn_number)

	check_connection_version(conn, remote_cmd)
	Log("Registering connection %d" % conn_number, 7)
	init_connection_routing(conn, conn_number, remote_cmd)
	init_connection_settings(conn)
	return conn

def check_connection_version(conn, remote_cmd):
	"""Log warning if connection has different version"""
	try: remote_version = conn.Globals.get('version')
	except ConnectionReadError, exception:
		Log.FatalError("""%s

Couldn't start up the remote connection by executing

    %s

Remember that, under the default settings, rdiff-backup must be
installed in the PATH on the remote system.  See the man page for more
information.""" % (exception, remote_cmd))
		
	if remote_version != Globals.version:
		Log("Warning: Local version %s does not match remote version %s."
			% (Globals.version, remote_version), 2)

def init_connection_routing(conn, conn_number, remote_cmd):
	"""Called by init_connection, establish routing, conn dict"""
	Globals.connection_dict[conn_number] = conn

	conn.SetConnections.init_connection_remote(conn_number)
	for other_remote_conn in Globals.connections[1:]:
		conn.SetConnections.add_redirected_conn(
			other_remote_conn.conn_number)
		other_remote_conn.SetConnections.add_redirected_conn(conn_number)

	Globals.connections.append(conn)
	__conn_remote_cmds.append(remote_cmd)

def init_connection_settings(conn):
	"""Tell new conn about log settings and updated globals"""
	conn.Log.setverbosity(Log.verbosity)
	conn.Log.setterm_verbosity(Log.term_verbosity)
	for setting_name in Globals.changed_settings:
		conn.Globals.set(setting_name, Globals.get(setting_name))
	FilenameMapping.set_init_quote_vals()

def init_connection_remote(conn_number):
	"""Run on server side to tell self that have given conn_number"""
	Globals.connection_number = conn_number
	Globals.local_connection.conn_number = conn_number
	Globals.connection_dict[0] = Globals.connections[1]
	Globals.connection_dict[conn_number] = Globals.local_connection

def add_redirected_conn(conn_number):
	"""Run on server side - tell about redirected connection"""
	Globals.connection_dict[conn_number] = \
		   RedirectedConnection(conn_number)

def UpdateGlobal(setting_name, val):
	"""Update value of global variable across all connections"""
	for conn in Globals.connections:
		conn.Globals.set(setting_name, val)

def BackupInitConnections(reading_conn, writing_conn):
	"""Backup specific connection initialization"""
	reading_conn.Globals.set("isbackup_reader", 1)
	writing_conn.Globals.set("isbackup_writer", 1)
	UpdateGlobal("backup_reader", reading_conn)
	UpdateGlobal("backup_writer", writing_conn)
	if (Globals.change_source_perms and
		reading_conn.Globals.get("process_uid") == 0):
		Log("Warning: --change_source_perms should usually not be used when\n"
			"the reading connection is running as root, because root can\n"
			"read all files regardless of their permissions.", 2)

def CloseConnections():
	"""Close all connections.  Run by client"""
	assert not Globals.server
	for conn in Globals.connections: conn.quit()
	del Globals.connections[1:] # Only leave local connection
	Globals.connection_dict = {0: Globals.local_connection}
	Globals.backup_reader = Globals.isbackup_reader = \
		  Globals.backup_writer = Globals.isbackup_writer = None

def TestConnections():
	"""Test connections, printing results"""
	if len(Globals.connections) == 1: print "No remote connections specified"
	else:
		for i in range(1, len(Globals.connections)): test_connection(i)

def test_connection(conn_number):
	"""Test connection.  conn_number 0 is the local connection"""
	print "Testing server started by: ", __conn_remote_cmds[conn_number]
	conn = Globals.connections[conn_number]
	try:
		assert conn.pow(2,3) == 8
		assert conn.os.path.join("a", "b") == "a/b"
		version = conn.reval("lambda: Globals.version")
	except:
		sys.stderr.write("Server tests failed\n")
		raise
	if not version == Globals.version:
		print """Server may work, but there is a version mismatch:
Local version: %s
Remote version: %s""" % (Globals.version, version)
	else: print "Server OK"


from log import *
from rpath import *
from connection import *
import Globals, FilenameMapping

