~bzr-pqm/bzr/bzr.dev

# Copyright (C) 2006 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

"""Test locks across all branch implemenations"""

from bzrlib import errors

from bzrlib.branch import BzrBranchFormat4

from bzrlib.bzrdir import RemoteBzrDirFormat

from bzrlib.tests import TestSkipped

from bzrlib.tests.branch_implementations.test_branch import TestCaseWithBranch

from bzrlib.tests.lock_helpers import TestPreventLocking, LockWrapper

class TestBranchLocking(TestCaseWithBranch):

    def setUp(self):

        TestCaseWithBranch.setUp(self)

        self.reduceLockdirTimeout()

    def get_instrumented_branch(self):

        """Get a Branch object which has been instrumented"""

        # TODO: jam 20060630 It may be that not all formats have a 

        # 'control_files' member. So we should fail gracefully if

        # not there. But assuming it has them lets us test the exact 

        # lock/unlock order.

        self.locks = []

        b = LockWrapper(self.locks, self.get_branch(), 'b')

        b.repository = LockWrapper(self.locks, b.repository, 'r')

        bcf = b.control_files

        rcf = getattr(b.repository, 'control_files', None)

        if rcf is None:

            self.combined_branch = False

        else:

            # Look out for branch types that reuse their control files

            self.combined_control = bcf is rcf

        try:

            b.control_files = LockWrapper(self.locks, b.control_files, 'bc')

        except AttributeError:

            # RemoteBranch seems to trigger this.

            raise TestSkipped("Could not instrument branch control files.")

        if self.combined_control:

            # instrument the repository control files too to ensure its worked

            # with correctly. When they are not shared, we trust the repository

            # API and only instrument the repository itself. 

            b.repository.control_files = \

                LockWrapper(self.locks, b.repository.control_files, 'rc')

        return b

    def test_01_lock_read(self):

        # Test that locking occurs in the correct order

        b = self.get_instrumented_branch()

        self.assertFalse(b.is_locked())

        self.assertFalse(b.repository.is_locked())

        b.lock_read()

        try:

            self.assertTrue(b.is_locked())

            self.assertTrue(b.repository.is_locked())

        finally:

            b.unlock()

        self.assertFalse(b.is_locked())

        self.assertFalse(b.repository.is_locked())

        if self.combined_control:

            self.assertEqual([('b', 'lr', True),

                              ('r', 'lr', True),

                              ('rc', 'lr', True),

                              ('bc', 'lr', True),

                              ('b', 'ul', True),

                              ('bc', 'ul', True),

                              ('r', 'ul', True),

                              ('rc', 'ul', True),

                             ], self.locks)

        else:

            self.assertEqual([('b', 'lr', True),

                              ('r', 'lr', True),

                              ('bc', 'lr', True),

                              ('b', 'ul', True),

                              ('bc', 'ul', True),

                              ('r', 'ul', True),

                             ], self.locks)

    def test_02_lock_write(self):

        # Test that locking occurs in the correct order

        b = self.get_instrumented_branch()

        self.assertFalse(b.is_locked())

        self.assertFalse(b.repository.is_locked())

        b.lock_write()

        try:

            self.assertTrue(b.is_locked())

            self.assertTrue(b.repository.is_locked())

        finally:

            b.unlock()

        self.assertFalse(b.is_locked())

        self.assertFalse(b.repository.is_locked())

        if self.combined_control:

            self.assertEqual([('b', 'lw', True),

                              ('r', 'lw', True),

                              ('rc', 'lw', True),

                              ('bc', 'lw', True),

                              ('b', 'ul', True),

                              ('bc', 'ul', True),

                              ('r', 'ul', True),

                              ('rc', 'ul', True),

                             ], self.locks)

        else:

            self.assertEqual([('b', 'lw', True),

                              ('r', 'lw', True),

                              ('bc', 'lw', True),

                              ('b', 'ul', True),

                              ('bc', 'ul', True),

                              ('r', 'ul', True),

                             ], self.locks)

    def test_03_lock_fail_unlock_repo(self):

        # Make sure branch.unlock() is called, even if there is a

        # failure while unlocking the repository.

        b = self.get_instrumented_branch()

        b.repository.disable_unlock()

        self.assertFalse(b.is_locked())

        self.assertFalse(b.repository.is_locked())

        b.lock_write()

        try:

            self.assertTrue(b.is_locked())

            self.assertTrue(b.repository.is_locked())

            self.assertRaises(TestPreventLocking, b.unlock)

            if self.combined_control:

                self.assertTrue(b.is_locked())

            else:

                self.assertFalse(b.is_locked())

            self.assertTrue(b.repository.is_locked())

            # We unlock the branch control files, even if 

            # we fail to unlock the repository

            if self.combined_control:

                self.assertEqual([('b', 'lw', True),

                                  ('r', 'lw', True),

                                  ('rc', 'lw', True),

                                  ('bc', 'lw', True),

                                  ('b', 'ul', True),

                                  ('bc', 'ul', True),

                                  ('r', 'ul', False),

                                 ], self.locks)

            else:

                self.assertEqual([('b', 'lw', True),

                                  ('r', 'lw', True),

                                  ('bc', 'lw', True),

                                  ('b', 'ul', True),

                                  ('bc', 'ul', True),

                                  ('r', 'ul', False),

                                 ], self.locks)

        finally:

            # For cleanup purposes, make sure we are unlocked

            b.repository._other.unlock()

    def test_04_lock_fail_unlock_control(self):

        # Make sure repository.unlock() is called, if we fail to unlock self

        b = self.get_instrumented_branch()

        b.control_files.disable_unlock()

        self.assertFalse(b.is_locked())

        self.assertFalse(b.repository.is_locked())

        b.lock_write()

        try:

            self.assertTrue(b.is_locked())

            self.assertTrue(b.repository.is_locked())

            self.assertRaises(TestPreventLocking, b.unlock)

            self.assertTrue(b.is_locked())

            if self.combined_control:

                self.assertTrue(b.repository.is_locked())

            else:

                self.assertFalse(b.repository.is_locked())

            # We unlock the repository even if 

            # we fail to unlock the control files

            if self.combined_control:

                self.assertEqual([('b', 'lw', True),

                                  ('r', 'lw', True),

                                  ('rc', 'lw', True),

                                  ('bc', 'lw', True),

                                  ('b', 'ul', True),

                                  ('bc', 'ul', False),

                                  ('r', 'ul', True),

                                  ('rc', 'ul', True),

                                 ], self.locks)

            else:

                self.assertEqual([('b', 'lw', True),

                                  ('r', 'lw', True),

                                  ('bc', 'lw', True),

                                  ('b', 'ul', True),

                                  ('bc', 'ul', False),

                                  ('r', 'ul', True),

                                 ], self.locks)

        finally:

            # For cleanup purposes, make sure we are unlocked

            b.control_files._other.unlock()

    def test_05_lock_read_fail_repo(self):

        # Test that the branch is not locked if it cannot lock the repository

        b = self.get_instrumented_branch()

        b.repository.disable_lock_read()

        self.assertRaises(TestPreventLocking, b.lock_read)

        self.assertFalse(b.is_locked())

        self.assertFalse(b.repository.is_locked())

        self.assertEqual([('b', 'lr', True),

                          ('r', 'lr', False), 

                         ], self.locks)

    def test_06_lock_write_fail_repo(self):

        # Test that the branch is not locked if it cannot lock the repository

        b = self.get_instrumented_branch()

        b.repository.disable_lock_write()

        self.assertRaises(TestPreventLocking, b.lock_write)

        self.assertFalse(b.is_locked())

        self.assertFalse(b.repository.is_locked())

        self.assertEqual([('b', 'lw', True),

                          ('r', 'lw', False), 

                         ], self.locks)

    def test_07_lock_read_fail_control(self):

        # Test the repository is unlocked if we can't lock self

        b = self.get_instrumented_branch()

        b.control_files.disable_lock_read()

        self.assertRaises(TestPreventLocking, b.lock_read)

        self.assertFalse(b.is_locked())

        self.assertFalse(b.repository.is_locked())

        if self.combined_control:

            self.assertEqual([('b', 'lr', True),

                              ('r', 'lr', True),

                              ('rc', 'lr', True),

                              ('bc', 'lr', False),

                              ('r', 'ul', True),

                              ('rc', 'ul', True),

                             ], self.locks)

        else:

            self.assertEqual([('b', 'lr', True),

                              ('r', 'lr', True),

                              ('bc', 'lr', False),

                              ('r', 'ul', True),

                             ], self.locks)

    def test_08_lock_write_fail_control(self):

        # Test the repository is unlocked if we can't lock self

        b = self.get_instrumented_branch()

        b.control_files.disable_lock_write()

        self.assertRaises(TestPreventLocking, b.lock_write)

        self.assertFalse(b.is_locked())

        self.assertFalse(b.repository.is_locked())

        if self.combined_control:

            self.assertEqual([('b', 'lw', True),

                              ('r', 'lw', True),

                              ('rc', 'lw', True),

                              ('bc', 'lw', False),

                              ('r', 'ul', True),

                              ('rc', 'ul', True),

                             ], self.locks)

        else:

            self.assertEqual([('b', 'lw', True),

                              ('r', 'lw', True),

                              ('bc', 'lw', False),

                              ('r', 'ul', True),

                             ], self.locks)

    def test_lock_write_returns_None_refuses_token(self):

        branch = self.make_branch('b')

        token = branch.lock_write()

        try:

            if token is not None:

                # This test does not apply, because this lockable supports

                # tokens.

                return

            self.assertRaises(errors.TokenLockingNotSupported,

                              branch.lock_write, token='token')

        finally:

            branch.unlock()

    def test_reentering_lock_write_raises_on_token_mismatch(self):

        branch = self.make_branch('b')

        token = branch.lock_write()

        try:

            if token is None:

                # This test does not apply, because this lockable refuses

                # tokens.

                return

            different_branch_token = token + 'xxx'

            # Re-using the same lockable instance with a different branch token

            # will raise TokenMismatch.

            self.assertRaises(errors.TokenMismatch,

                              branch.lock_write,

                              token=different_branch_token)

        finally:

            branch.unlock()

    def test_lock_write_with_nonmatching_token(self):

        branch = self.make_branch('b')

        token = branch.lock_write()

        try:

            if token is None:

                # This test does not apply, because this branch refuses

                # tokens.

                return

            different_branch_token = token + 'xxx'

            new_branch = branch.bzrdir.open_branch()

            # We only want to test the relocking abilities of branch, so use the

            # existing repository object which is already locked.

            new_branch.repository = branch.repository

            self.assertRaises(errors.TokenMismatch,

                              new_branch.lock_write,

                              token=different_branch_token)

        finally:

            branch.unlock()

    def test_lock_write_with_matching_token(self):

        """Test that a branch can be locked with a token, if it is already

        locked by that token."""

        branch = self.make_branch('b')

        token = branch.lock_write()

        try:

            if token is None:

                # This test does not apply, because this branch refuses tokens.

                return

            # The same instance will accept a second lock_write if the specified

            # token matches.

            branch.lock_write(token=token)

            branch.unlock()

            # Calling lock_write on a new instance for the same lockable will

            # also succeed.

            new_branch = branch.bzrdir.open_branch()

            # We only want to test the relocking abilities of branch, so use the

            # existing repository object which is already locked.

            new_branch.repository = branch.repository

            new_branch.lock_write(token=token)

            new_branch.unlock()

        finally:

            branch.unlock()

    def test_unlock_after_lock_write_with_token(self):

        # If lock_write did not physically acquire the lock (because it was

        # passed some tokens), then unlock should not physically release it.

        branch = self.make_branch('b')

        token = branch.lock_write()

        try:

            if token is None:

                # This test does not apply, because this lockable refuses

                # tokens.

                return

            new_branch = branch.bzrdir.open_branch()

            # We only want to test the relocking abilities of branch, so use the

            # existing repository object which is already locked.

            new_branch.repository = branch.repository

            new_branch.lock_write(token=token)

            new_branch.unlock()

            self.assertTrue(branch.get_physical_lock_status()) #XXX

        finally:

            branch.unlock()

    def test_lock_write_with_token_fails_when_unlocked(self):

        # First, lock and then unlock to get superficially valid tokens.  This

        # mimics a likely programming error, where a caller accidentally tries

        # to lock with a token that is no longer valid (because the original

        # lock was released).

        branch = self.make_branch('b')

        token = branch.lock_write()

        branch.unlock()

        if token is None:

            # This test does not apply, because this lockable refuses

            # tokens.

            return

        self.assertRaises(errors.TokenMismatch,

                          branch.lock_write, token=token)

    def test_lock_write_reenter_with_token(self):

        branch = self.make_branch('b')

        token = branch.lock_write()

        try:

            if token is None:

                # This test does not apply, because this lockable refuses

                # tokens.

                return

            # Relock with a token.

            branch.lock_write(token=token)

            branch.unlock()

        finally:

            branch.unlock()

        # The lock should be unlocked on disk.  Verify that with a new lock

        # instance.

        new_branch = branch.bzrdir.open_branch()

        # Calling lock_write now should work, rather than raise LockContention.

        new_branch.lock_write()

        new_branch.unlock()

    def test_leave_lock_in_place(self):

        branch = self.make_branch('b')

        # Lock the branch, then use leave_lock_in_place so that when we

        # unlock the branch the lock is still held on disk.

        token = branch.lock_write()

        try:

            if token is None:

                # This test does not apply, because this repository refuses lock

                # tokens.

                self.assertRaises(NotImplementedError,

                                  branch.leave_lock_in_place)

                return

            branch.leave_lock_in_place()

        finally:

            branch.unlock()

        # We should be unable to relock the repo.

        self.assertRaises(errors.LockContention, branch.lock_write)

    def test_dont_leave_lock_in_place(self):

        branch = self.make_branch('b')

        # Create a lock on disk.

        token = branch.lock_write()

        try:

            if token is None:

                # This test does not apply, because this branch refuses lock

                # tokens.

                self.assertRaises(NotImplementedError,

                                  branch.dont_leave_lock_in_place)

                return

            try:

                branch.leave_lock_in_place()

            except NotImplementedError:

                # This branch doesn't support this API.

                return

            try:

                branch.repository.leave_lock_in_place()

            except NotImplementedError:

                # This repo doesn't support leaving locks around,

                # assume it is essentially lock-free.

                repo_token = None

            else:

                repo_token = branch.repository.lock_write()

                branch.repository.unlock()

        finally:

            branch.unlock()

        # Reacquire the lock (with a different branch object) by using the

        # tokens.

        new_branch = branch.bzrdir.open_branch()

        if repo_token is not None:

            # We have to explicitly lock the repository first.

            new_branch.repository.lock_write(token=repo_token)

        new_branch.lock_write(token=token)

        if repo_token is not None:

            # Now we don't need our own repository lock anymore (the branch is

            # holding it for us).

            new_branch.repository.unlock()

        # Call dont_leave_lock_in_place, so that the lock will be released by

        # this instance, even though the lock wasn't originally acquired by it.

        new_branch.dont_leave_lock_in_place()

        if repo_token is not None:

            new_branch.repository.dont_leave_lock_in_place()

        new_branch.unlock()

        # Now the branch (and repository) is unlocked.  Test this by locking it

        # without tokens.

        branch.lock_write()

        branch.unlock()

    def test_lock_read_then_unlock(self):

        # Calling lock_read then unlocking should work without errors.

        branch = self.make_branch('b')

        branch.lock_read()

        branch.unlock()

    def test_lock_write_locks_repo_too(self):

        if isinstance(self.branch_format, BzrBranchFormat4):

            # Branch format 4 is combined with the repository, so this test

            # doesn't apply.

            return

        branch = self.make_branch('b')

        branch = branch.bzrdir.open_branch()

        branch.lock_write()

        try:

            # The branch should have asked the repository to lock.

            self.assertTrue(branch.repository.is_write_locked())

            # Does the repository type actually lock?

            if not branch.repository.get_physical_lock_status():

                # The test was successfully applied, so it was applicable.

                return

            # Now the branch.repository is physically locked, so we can't lock

            # it with a new repository instance.

            new_repo = branch.bzrdir.open_repository()

            self.assertRaises(errors.LockContention, new_repo.lock_write)

            # We can call lock_write on the original repository object though,

            # because it is already locked.

            branch.repository.lock_write()

            branch.repository.unlock()

        finally:

            branch.unlock()