# Copyright (C) 2006, 2007 Canonical Ltd
#
# 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 2 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, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

"""Blackbox tests for debugger breakin"""

import errno
import os
import signal
import subprocess
import sys
import time

from bzrlib import (
    errors,
    tests,
    )


class TestBreakin(tests.TestCase):
    # FIXME: If something is broken, these tests may just hang indefinitely in
    # wait() waiting for the child to exit when it's not going to.

    def setUp(self):
        if sys.platform == 'win32':
            raise tests.TestSkipped('breakin signal not tested on win32')
        super(TestBreakin, self).setUp()

    def _dont_SIGQUIT_on_darwin(self):
        if sys.platform == 'darwin':
            # At least on Leopard and with python 2.6, this test will raise a
            # popup window asking if the python failure should be reported to
            # Apple... That's not the point of the test :) Marking the test as
            # not applicable Until we find a way to disable that intrusive
            # behavior... --vila20080611
            raise tests.TestNotApplicable(
                '%s raises a popup on OSX' % self.id())

    def _wait_for_process(self, pid, sig=None):
        # We don't know quite how long waiting for the process 'pid' will take,
        # but if it's more than 10s then it's probably not going to work.
        for i in range(100):
            time.sleep(0.1)
            if sig is not None:
                os.kill(pid, sig)
            # Use WNOHANG to ensure we don't get blocked, doing so, we may
            # leave the process continue after *we* die...
            try:
                # note: waitpid is different on win32, but this test only runs
                # on unix
                pid_killed, returncode = os.waitpid(pid, os.WNOHANG)
                if (pid_killed, returncode) != (0, 0):
                    if sig is not None:
                        # high bit in low byte says if core was dumped; we
                        # don't care
                        status, sig = (returncode >> 8, returncode & 0x7f)
                        return True, sig
            except OSError, e:
                if e.errno in (errno.ECHILD, errno.ESRCH):
                    # The process doesn't exist anymore
                    return True, None
                else:
                    raise

        return False, None

    # port 0 means to allocate any port
    _test_process_args = ['serve', '--port', 'localhost:0']

    def test_breakin(self):
        # Break in to a debugger while bzr is running
        # we need to test against a command that will wait for
        # a while -- bzr serve should do
        proc = self.start_bzr_subprocess(self._test_process_args,
                env_changes=dict(BZR_SIGQUIT_PDB=None))
        # wait for it to get started, and print the 'listening' line
        proc.stderr.readline()
        # first sigquit pops into debugger
        os.kill(proc.pid, signal.SIGQUIT)
        # Wait for the debugger to acknowledge the signal reception
        err = proc.stderr.readline()
        self.assertContainsRe(err, r'entering debugger')
        # Now that the debugger is entered, we can ask him to quit
        proc.stdin.write("q\n")
        # We wait a bit to let the child process handles our query and avoid
        # triggering deadlocks leading to hangs on multi-core hosts...
        dead, sig = self._wait_for_process(proc.pid)
        if not dead:
            # The process didn't finish, let's kill it before reporting failure
            dead, sig = self._wait_for_process(proc.pid, signal.SIGKILL)
            if dead:
                raise tests.KnownFailure(
                    "subprocess wasn't terminated, it had to be killed")
            else:
                self.fail("subprocess %d wasn't terminated by repeated SIGKILL",
                          proc.pid)

    def test_breakin_harder(self):
        """SIGQUITting twice ends the process."""
        self._dont_SIGQUIT_on_darwin()
        proc = self.start_bzr_subprocess(self._test_process_args,
                env_changes=dict(BZR_SIGQUIT_PDB=None))
        # wait for it to get started, and print the 'listening' line
        proc.stderr.readline()
        # break into the debugger
        os.kill(proc.pid, signal.SIGQUIT)
        # Wait for the debugger to acknowledge the signal reception (since we
        # want to send a second signal, we ensure it doesn't get lost by
        # validating the first get received and produce its effect).
        err = proc.stderr.readline()
        self.assertContainsRe(err, r'entering debugger')
        dead, sig = self._wait_for_process(proc.pid, signal.SIGQUIT)
        self.assertTrue((dead and sig == signal.SIGQUIT),
                        msg="subprocess wasn't terminated by repeated SIGQUIT")

    def test_breakin_disabled(self):
        self._dont_SIGQUIT_on_darwin()
        proc = self.start_bzr_subprocess(self._test_process_args,
                env_changes=dict(BZR_SIGQUIT_PDB='0'))
        # wait for it to get started, and print the 'listening' line
        proc.stderr.readline()
        # first hit should just kill it
        os.kill(proc.pid, signal.SIGQUIT)
        proc.wait()