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# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this file,
# You can obtain one at http://mozilla.org/MPL/2.0/.
from __future__ import unicode_literals
class HostsLine(object):
def __init__(self, ip_address, canonical_hostname, aliases=None, comment=None):
self.ip_address = ip_address
self.canonical_hostname = canonical_hostname
self.aliases = aliases if aliases is not None else []
self.comment = comment
if self.ip_address is None:
assert self.canonical_hostname is None
assert not self.aliases
assert self.comment is not None
@classmethod
def from_string(cls, line):
if not line.strip():
return
line = line.strip()
ip_address = None
canonical_hostname = None
aliases = []
comment = None
comment_parts = line.split("#", 1)
if len(comment_parts) > 1:
comment = comment_parts[1]
data = comment_parts[0].strip()
if data:
fields = data.split()
if len(fields) < 2:
raise ValueError("Invalid hosts line")
ip_address = fields[0]
canonical_hostname = fields[1]
aliases = fields[2:]
return cls(ip_address, canonical_hostname, aliases, comment)
class HostsFile(object):
def __init__(self):
self.data = []
self.by_hostname = {}
def set_host(self, host):
if host.canonical_hostname is None:
self.data.append(host)
elif host.canonical_hostname in self.by_hostname:
old_host = self.by_hostname[host.canonical_hostname]
old_host.ip_address = host.ip_address
old_host.aliases = host.aliases
old_host.comment = host.comment
else:
self.data.append(host)
self.by_hostname[host.canonical_hostname] = host
@classmethod
def from_file(cls, f):
rv = cls()
for line in f:
host = HostsLine.from_string(line)
if host is not None:
rv.set_host(host)
return rv
def to_string(self):
field_widths = [0, 0]
for line in self.data:
if line.ip_address is not None:
field_widths[0] = max(field_widths[0], len(line.ip_address))
field_widths[1] = max(field_widths[1], len(line.canonical_hostname))
lines = []
for host in self.data:
line = ""
if host.ip_address is not None:
ip_string = host.ip_address.ljust(field_widths[0])
hostname_str = host.canonical_hostname
if host.aliases:
hostname_str = "%s %s" % (hostname_str.ljust(field_widths[1]),
" ".join(host.aliases))
line = "%s %s" % (ip_string, hostname_str)
if host.comment:
if line:
line += " "
line += "#%s" % host.comment
lines.append(line)
lines.append("")
return "\n".join(lines)
def to_file(self, f):
f.write(self.to_string().encode("utf8"))
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