Python gc.isenabled() Examples

def setUp(self):
        """
        Replace L{process} os, fcntl, sys, switchUID, fdesc and pty modules
        with the mock class L{MockOS}.
        """
        if gc.isenabled():
            self.addCleanup(gc.enable)
        else:
            self.addCleanup(gc.disable)
        self.mockos = MockOS()
        self.mockos.euid = 1236
        self.mockos.egid = 1234
        self.patch(process, "os", self.mockos)
        self.patch(process, "fcntl", self.mockos)
        self.patch(process, "sys", self.mockos)
        self.patch(process, "switchUID", self.mockos.switchUID)
        self.patch(process, "fdesc", self.mockos)
        self.patch(process.Process, "processReaderFactory", DumbProcessReader)
        self.patch(process.Process, "processWriterFactory", DumbProcessWriter)
        self.patch(process, "pty", self.mockos)

        self.mocksig = MockSignal()
        self.patch(process, "signal", self.mocksig) 

def timeit(self, number=default_number):
        """Time 'number' executions of the main statement.

        To be precise, this executes the setup statement once, and
        then returns the time it takes to execute the main statement
        a number of times, as a float measured in seconds.  The
        argument is the number of times through the loop, defaulting
        to one million.  The main statement, the setup statement and
        the timer function to be used are passed to the constructor.
        """
        if itertools:
            it = itertools.repeat(None, number)
        else:
            it = [None] * number
        gcold = gc.isenabled()
        gc.disable()
        try:
            timing = self.inner(it, self.timer)
        finally:
            if gcold:
                gc.enable()
        return timing 

def test_get_stats(self):
        stats = gc.get_stats()
        self.assertEqual(len(stats), 3)
        for st in stats:
            self.assertIsInstance(st, dict)
            self.assertEqual(set(st),
                             {"collected", "collections", "uncollectable"})
            self.assertGreaterEqual(st["collected"], 0)
            self.assertGreaterEqual(st["collections"], 0)
            self.assertGreaterEqual(st["uncollectable"], 0)
        # Check that collection counts are incremented correctly
        if gc.isenabled():
            self.addCleanup(gc.enable)
            gc.disable()
        old = gc.get_stats()
        gc.collect(0)
        new = gc.get_stats()
        self.assertEqual(new[0]["collections"], old[0]["collections"] + 1)
        self.assertEqual(new[1]["collections"], old[1]["collections"])
        self.assertEqual(new[2]["collections"], old[2]["collections"])
        gc.collect(2)
        new = gc.get_stats()
        self.assertEqual(new[0]["collections"], old[0]["collections"] + 1)
        self.assertEqual(new[1]["collections"], old[1]["collections"])
        self.assertEqual(new[2]["collections"], old[2]["collections"] + 1) 

def test_load_refcount():
    # Check that objects returned by np.load are directly freed based on
    # their refcount, rather than needing the gc to collect them.

    f = BytesIO()
    np.savez(f, [1, 2, 3])
    f.seek(0)

    assert_(gc.isenabled())
    gc.disable()
    try:
        gc.collect()
        np.load(f)
        # gc.collect returns the number of unreachable objects in cycles that
        # were found -- we are checking that no cycles were created by np.load
        n_objects_in_cycles = gc.collect()
    finally:
        gc.enable()
    assert_equal(n_objects_in_cycles, 0) 

def test_free_from_gc(self):
        # Check that freeing of blocks by the garbage collector doesn't deadlock
        # (issue #12352).
        # Make sure the GC is enabled, and set lower collection thresholds to
        # make collections more frequent (and increase the probability of
        # deadlock).
        if not gc.isenabled():
            gc.enable()
            self.addCleanup(gc.disable)
        thresholds = gc.get_threshold()
        self.addCleanup(gc.set_threshold, *thresholds)
        gc.set_threshold(10)

        # perform numerous block allocations, with cyclic references to make
        # sure objects are collected asynchronously by the gc
        for i in range(5000):
            a = multiprocessing.heap.BufferWrapper(1)
            b = multiprocessing.heap.BufferWrapper(1)
            # circular references
            a.buddy = b
            b.buddy = a

#
#
# 

def gc_state(state):
    """ Context manager to set state of garbage collector to `state`

    Parameters
    ----------
    state : bool
        True for gc enabled, False for disabled

    Examples
    --------
    >>> with gc_state(False):
    ...     assert not gc.isenabled()
    >>> with gc_state(True):
    ...     assert gc.isenabled()
    """
    orig_state = gc.isenabled()
    set_gc_state(state)
    yield
    set_gc_state(orig_state) 

def test_free_from_gc(self):
        # Check that freeing of blocks by the garbage collector doesn't deadlock
        # (issue #12352).
        # Make sure the GC is enabled, and set lower collection thresholds to
        # make collections more frequent (and increase the probability of
        # deadlock).
        if not gc.isenabled():
            gc.enable()
            self.addCleanup(gc.disable)
        thresholds = gc.get_threshold()
        self.addCleanup(gc.set_threshold, *thresholds)
        gc.set_threshold(10)

        # perform numerous block allocations, with cyclic references to make
        # sure objects are collected asynchronously by the gc
        for i in range(5000):
            a = multiprocessing.heap.BufferWrapper(1)
            b = multiprocessing.heap.BufferWrapper(1)
            # circular references
            a.buddy = b
            b.buddy = a

#
#
# 

def timeit(self, number=default_number):
        """Time 'number' executions of the main statement.

        To be precise, this executes the setup statement once, and
        then returns the time it takes to execute the main statement
        a number of times, as a float measured in seconds.  The
        argument is the number of times through the loop, defaulting
        to one million.  The main statement, the setup statement and
        the timer function to be used are passed to the constructor.
        """
        if itertools:
            it = itertools.repeat(None, number)
        else:
            it = [None] * number
        gcold = gc.isenabled()
        gc.disable()
        timing = self.inner(it, self.timer)
        if gcold:
            gc.enable()
        return timing 

def timeit(self, number=default_number):
        """Time 'number' executions of the main statement.

        To be precise, this executes the setup statement once, and
        then returns the time it takes to execute the main statement
        a number of times, as a float measured in seconds.  The
        argument is the number of times through the loop, defaulting
        to one million.  The main statement, the setup statement and
        the timer function to be used are passed to the constructor.
        """
        it = itertools.repeat(None, number)
        gcold = gc.isenabled()
        gc.disable()
        try:
            timing = self.inner(it, self.timer)
        finally:
            if gcold:
                gc.enable()
        return timing 

def test_load_refcount():
    # Check that objects returned by np.load are directly freed based on
    # their refcount, rather than needing the gc to collect them.

    f = BytesIO()
    np.savez(f, [1, 2, 3])
    f.seek(0)

    assert_(gc.isenabled())
    gc.disable()
    try:
        gc.collect()
        np.load(f)
        # gc.collect returns the number of unreachable objects in cycles that
        # were found -- we are checking that no cycles were created by np.load
        n_objects_in_cycles = gc.collect()
    finally:
        gc.enable()
    assert_equal(n_objects_in_cycles, 0) 

def timeit(self, number=default_number):
        """Time 'number' executions of the main statement.

        To be precise, this executes the setup statement once, and
        then returns the time it takes to execute the main statement
        a number of times, as a float measured in seconds.  The
        argument is the number of times through the loop, defaulting
        to one million.  The main statement, the setup statement and
        the timer function to be used are passed to the constructor.
        """
        if itertools:
            it = itertools.repeat(None, number)
        else:
            it = [None] * number
        gcold = gc.isenabled()
        gc.disable()
        try:
            timing = self.inner(it, self.timer)
        finally:
            if gcold:
                gc.enable()
        return timing 

def test_load_refcount():
    # Check that objects returned by np.load are directly freed based on
    # their refcount, rather than needing the gc to collect them.

    f = BytesIO()
    np.savez(f, [1, 2, 3])
    f.seek(0)

    assert_(gc.isenabled())
    gc.disable()
    try:
        gc.collect()
        np.load(f)
        # gc.collect returns the number of unreachable objects in cycles that
        # were found -- we are checking that no cycles were created by np.load
        n_objects_in_cycles = gc.collect()
    finally:
        gc.enable()
    assert_equal(n_objects_in_cycles, 0) 

def timeit(self, number=default_number):
        """Time 'number' executions of the main statement.

        To be precise, this executes the setup statement once, and
        then returns the time it takes to execute the main statement
        a number of times, as a float measured in seconds.  The
        argument is the number of times through the loop, defaulting
        to one million.  The main statement, the setup statement and
        the timer function to be used are passed to the constructor.
        """
        it = itertools.repeat(None, number)
        gcold = gc.isenabled()
        gc.disable()
        try:
            timing = self.inner(it, self.timer)
        finally:
            if gcold:
                gc.enable()
        return timing 

def test_gc_state():
    # Test gc_state context manager
    gc_status = gc.isenabled()
    try:
        for pre_state in (True, False):
            set_gc_state(pre_state)
            for with_state in (True, False):
                # Check the gc state is with_state in with block
                with gc_state(with_state):
                    assert_equal(gc.isenabled(), with_state)
                # And returns to previous state outside block
                assert_equal(gc.isenabled(), pre_state)
                # Even if the gc state is set explicitly within the block
                with gc_state(with_state):
                    assert_equal(gc.isenabled(), with_state)
                    set_gc_state(not with_state)
                assert_equal(gc.isenabled(), pre_state)
    finally:
        if gc_status:
            gc.enable() 

def timeit(self, number=default_number):
        """Time 'number' executions of the main statement.

        To be precise, this executes the setup statement once, and
        then returns the time it takes to execute the main statement
        a number of times, as a float measured in seconds.  The
        argument is the number of times through the loop, defaulting
        to one million.  The main statement, the setup statement and
        the timer function to be used are passed to the constructor.
        """
        it = itertools.repeat(None, number)
        gcold = gc.isenabled()
        gc.disable()
        try:
            timing = self.inner(it, self.timer)
        finally:
            if gcold:
                gc.enable()
        return timing 

def test_mockFork(self):
        """
        Test a classic spawnProcess. Check the path of the client code:
        fork, exec, exit.
        """
        gc.enable()

        cmd = b'/mock/ouch'

        d = defer.Deferred()
        p = TrivialProcessProtocol(d)
        try:
            reactor.spawnProcess(p, cmd, [b'ouch'], env=None,
                                 usePTY=False)
        except SystemError:
            self.assertTrue(self.mockos.exited)
            self.assertEqual(
                self.mockos.actions, [("fork", False), "exec", ("exit", 1)])
        else:
            self.fail("Should not be here")

        # It should leave the garbage collector disabled.
        self.assertFalse(gc.isenabled()) 

def test_getWorkerArguments(self):
        """
        C{_getWorkerArguments} discards options like C{random} as they only
        matter in the manager, and forwards options like C{recursionlimit} or
        C{disablegc}.
        """
        self.addCleanup(sys.setrecursionlimit, sys.getrecursionlimit())
        if gc.isenabled():
            self.addCleanup(gc.enable)

        self.options.parseOptions(["--recursionlimit", "2000", "--random",
                                   "4", "--disablegc"])
        args = self.options._getWorkerArguments()
        self.assertIn("--disablegc", args)
        args.remove("--disablegc")
        self.assertEqual(["--recursionlimit", "2000"], args) 

def test_main():
    enabled = gc.isenabled()
    gc.disable()
    assert not gc.isenabled()
    debug = gc.get_debug()
    gc.set_debug(debug & ~gc.DEBUG_LEAK) # this test is supposed to leak

    try:
        gc.collect() # Delete 2nd generation garbage
        run_unittest(GCTests, GCTogglingTests)
    finally:
        gc.set_debug(debug)
        # test gc.enable() even if GC is disabled by default
        if verbose:
            print "restoring automatic collection"
        # make sure to always test gc.enable()
        gc.enable()
        assert gc.isenabled()
        if not enabled:
            gc.disable() 

def timeit(self, number=default_number):
        """Time 'number' executions of the main statement.

        To be precise, this executes the setup statement once, and
        then returns the time it takes to execute the main statement
        a number of times, as a float measured in seconds.  The
        argument is the number of times through the loop, defaulting
        to one million.  The main statement, the setup statement and
        the timer function to be used are passed to the constructor.
        """
        if itertools:
            it = itertools.repeat(None, number)
        else:
            it = [None] * number
        gcold = gc.isenabled()
        gc.disable()
        try:
            timing = self.inner(it, self.timer)
        finally:
            if gcold:
                gc.enable()
        return timing 

def test_gc_state():
    # Test gc_state context manager
    gc_status = gc.isenabled()
    try:
        for pre_state in (True, False):
            set_gc_state(pre_state)
            for with_state in (True, False):
                # Check the gc state is with_state in with block
                with gc_state(with_state):
                    assert_equal(gc.isenabled(), with_state)
                # And returns to previous state outside block
                assert_equal(gc.isenabled(), pre_state)
                # Even if the gc state is set explicitly within the block
                with gc_state(with_state):
                    assert_equal(gc.isenabled(), with_state)
                    set_gc_state(not with_state)
                assert_equal(gc.isenabled(), pre_state)
    finally:
        if gc_status:
            gc.enable() 

def gc_state(state):
    """ Context manager to set state of garbage collector to `state`

    Parameters
    ----------
    state : bool
        True for gc enabled, False for disabled

    Examples
    --------
    >>> with gc_state(False):
    ...     assert not gc.isenabled()
    >>> with gc_state(True):
    ...     assert gc.isenabled()
    """
    orig_state = gc.isenabled()
    set_gc_state(state)
    yield
    set_gc_state(orig_state) 

def timeit(self, number=default_number):
        """Time 'number' executions of the main statement.

        To be precise, this executes the setup statement once, and
        then returns the time it takes to execute the main statement
        a number of times, as a float measured in seconds.  The
        argument is the number of times through the loop, defaulting
        to one million.  The main statement, the setup statement and
        the timer function to be used are passed to the constructor.
        """
        if itertools:
            it = itertools.repeat(None, number)
        else:
            it = [None] * number
        gcold = gc.isenabled()
        gc.disable()
        timing = self.inner(it, self.timer)
        if gcold:
            gc.enable()
        return timing 

def test_main():
    enabled = gc.isenabled()
    gc.disable()
    assert not gc.isenabled()
    debug = gc.get_debug()
    gc.set_debug(debug & ~gc.DEBUG_LEAK) # this test is supposed to leak

    try:
        gc.collect() # Delete 2nd generation garbage
        run_unittest(GCTests, GCTogglingTests)
    finally:
        gc.set_debug(debug)
        # test gc.enable() even if GC is disabled by default
        if verbose:
            print "restoring automatic collection"
        # make sure to always test gc.enable()
        gc.enable()
        assert gc.isenabled()
        if not enabled:
            gc.disable() 

def gc_state(state):
    """ Context manager to set state of garbage collector to `state`

    Parameters
    ----------
    state : bool
        True for gc enabled, False for disabled

    Examples
    --------
    >>> with gc_state(False):
    ...     assert not gc.isenabled()
    >>> with gc_state(True):
    ...     assert gc.isenabled()
    """
    orig_state = gc.isenabled()
    set_gc_state(state)
    yield
    set_gc_state(orig_state) 

def timeit(self, number=default_number):
        """Time 'number' executions of the main statement.

        To be precise, this executes the setup statement once, and
        then returns the time it takes to execute the main statement
        a number of times, as a float measured in seconds.  The
        argument is the number of times through the loop, defaulting
        to one million.  The main statement, the setup statement and
        the timer function to be used are passed to the constructor.
        """
        if itertools:
            it = itertools.repeat(None, number)
        else:
            it = [None] * number
        gcold = gc.isenabled()
        gc.disable()
        try:
            timing = self.inner(it, self.timer)
        finally:
            if gcold:
                gc.enable()
        return timing 

def test_mockWithForkErrorGarbageCollectorDisabled(self):
        """
        The garbage collector should be disabled when
        L{reactor.spawnProcess} raises because L{os.fork} raised, if it was
        initially disabled.
        """
        gc.disable()
        self._mockWithForkError()
        self.assertFalse(gc.isenabled()) 

def _exitfunc(cls):
        # At shutdown invoke finalizers for which atexit is true.
        # This is called once all other non-daemonic threads have been
        # joined.
        reenable_gc = False
        try:
            if cls._registry:
                import gc
                if gc.isenabled():
                    reenable_gc = True
                    gc.disable()
                pending = None
                while True:
                    if pending is None or finalize._dirty:
                        pending = cls._select_for_exit()
                        finalize._dirty = False
                    if not pending:
                        break
                    f = pending.pop()
                    try:
                        # gc is disabled, so (assuming no daemonic
                        # threads) the following is the only line in
                        # this function which might trigger creation
                        # of a new finalizer
                        f()
                    except Exception:
                        sys.excepthook(*sys.exc_info())
                    assert f not in cls._registry
        finally:
            # prevent any more finalizers from executing during shutdown
            finalize._shutdown = True
            if reenable_gc:
                gc.enable() 

def _exitfunc(cls):
        # At shutdown invoke finalizers for which atexit is true.
        # This is called once all other non-daemonic threads have been
        # joined.
        reenable_gc = False
        try:
            if cls._registry:
                import gc
                if gc.isenabled():
                    reenable_gc = True
                    gc.disable()
                pending = None
                while True:
                    if pending is None or finalize._dirty:
                        pending = cls._select_for_exit()
                        finalize._dirty = False
                    if not pending:
                        break
                    f = pending.pop()
                    try:
                        # gc is disabled, so (assuming no daemonic
                        # threads) the following is the only line in
                        # this function which might trigger creation
                        # of a new finalizer
                        f()
                    except Exception:
                        sys.excepthook(*sys.exc_info())
                    assert f not in cls._registry
        finally:
            # prevent any more finalizers from executing during shutdown
            finalize._shutdown = True
            if reenable_gc:
                gc.enable() 

def _exitfunc(cls):
        # At shutdown invoke finalizers for which atexit is true.
        # This is called once all other non-daemonic threads have been
        # joined.
        reenable_gc = False
        try:
            if cls._registry:
                import gc
                if gc.isenabled():
                    reenable_gc = True
                    gc.disable()
                pending = None
                while True:
                    if pending is None or finalize._dirty:
                        pending = cls._select_for_exit()
                        finalize._dirty = False
                    if not pending:
                        break
                    f = pending.pop()
                    try:
                        # gc is disabled, so (assuming no daemonic
                        # threads) the following is the only line in
                        # this function which might trigger creation
                        # of a new finalizer
                        f()
                    except Exception:
                        sys.excepthook(*sys.exc_info())
                    assert f not in cls._registry
        finally:
            # prevent any more finalizers from executing during shutdown
            finalize._shutdown = True
            if reenable_gc:
                gc.enable() 

def test_mockForkInParentGarbageCollectorDisabled(self):
        """
        The garbage collector should be disabled when L{reactor.spawnProcess}
        returns if it was initially disabled.

        @see L{_mockForkInParentTest}
        """
        gc.disable()
        self._mockForkInParentTest()
        self.assertFalse(gc.isenabled())