#!/usr/bin/env python

# Copyright (C) 2016 g10 Code GmbH

#

# This file is part of GPGME.

#

# GPGME 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 2 of the License, or

# (at your option) any later version.

#

# GPGME 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 Lesser General

# Public License for more details.

#

# You should have received a copy of the GNU Lesser General Public

# License along with this program; if not, see <https://www.gnu.org/licenses/>.

from __future__ import absolute_import, print_function, unicode_literals

import sys

import io

import os

import tempfile

import gpg

import support

_ = support  # to appease pyflakes.

del absolute_import, print_function, unicode_literals

# Both Context and Data can be used as context manager:

with gpg.Context() as c, gpg.Data() as d:

    c.get_engine_info()

    d.write(b"Halloechen")

    leak_c = c

    leak_d = d

assert leak_c.wrapped is None

assert leak_d.wrapped is None

def sign_and_verify(source, signed, sink):

    with gpg.Context() as c:

        c.op_sign(source, signed, gpg.constants.sig.mode.NORMAL)

        signed.seek(0, os.SEEK_SET)

        c.op_verify(signed, None, sink)

        result = c.op_verify_result()

    assert len(result.signatures) == 1, "Unexpected number of signatures"

    sig = result.signatures[0]

    assert sig.summary == (gpg.constants.sigsum.VALID |

                           gpg.constants.sigsum.GREEN)

    assert gpg.errors.GPGMEError(sig.status).getcode() == gpg.errors.NO_ERROR

    sink.seek(0, os.SEEK_SET)

    assert sink.read() == b"Hallo Leute\n"

# Demonstrate automatic wrapping of file-like objects with 'fileno'

# method.

with tempfile.TemporaryFile() as source, \

     tempfile.TemporaryFile() as signed, \

     tempfile.TemporaryFile() as sink:

    source.write(b"Hallo Leute\n")

    source.seek(0, os.SEEK_SET)

    sign_and_verify(source, signed, sink)

if sys.version_info[0] == 3:

    # Python2's io.BytesIO does not implement the buffer interface,

    # hence we cannot use it as sink.

    # XXX: Python's io.BytesIo.truncate does not work as advertised.

    # https://bugs.python.org/issue27261

    bio = io.BytesIO()

    bio.truncate(1)

    if len(bio.getvalue()) != 1:

        # This version of Python is affected, preallocate buffer.

        preallocate = 128 * b'\x00'

    else:

        preallocate = b''

    # Demonstrate automatic wrapping of objects implementing the buffer

    # interface, and the use of data objects with the 'with' statement.

    with io.BytesIO(preallocate) as signed, gpg.Data() as sink:

        sign_and_verify(b"Hallo Leute\n", signed, sink)