##############################################################################
#
# Copyright (c) 2004-2008 Zope Foundation and Contributors.
# All Rights Reserved.
#
# This software is subject to the provisions of the Zope Public License,
# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
# FOR A PARTICULAR PURPOSE.
#
##############################################################################
"""Support for tracking reference counts.
"""
from __future__ import print_function

import gc
import sys
import types


class TrackRefs(object):
    """Object to track reference counts across test runs."""

    def __init__(self):
        self.type2count = {}
        self.type2all = {}
        self.delta = None
        self.n = 0
        self.update()
        self.delta = None

    def update(self):
        gc.collect()
        obs = sys.getobjects(0)
        type2count = {}
        type2all = {}
        n = 0
        for o in obs:
            if type(o) is str and o == '<dummy key>':
                # avoid dictionary madness
                continue

            all = sys.getrefcount(o) - 3
            n += all

            t = type(o)
            if t is types.InstanceType:
                t = o.__class__

            if t in type2count:
                type2count[t] += 1
                type2all[t] += all
            else:
                type2count[t] = 1
                type2all[t] = all


        ct = [(
               type_or_class_title(t),
               type2count[t] - self.type2count.get(t, 0),
               type2all[t] - self.type2all.get(t, 0),
               )
              for t in type2count]
        ct += [(
                type_or_class_title(t),
                - self.type2count[t],
                - self.type2all[t],
                )
               for t in self.type2count
               if t not in type2count]
        ct.sort()
        self.delta = ct
        self.type2count = type2count
        self.type2all = type2all
        self.n = n


    def output(self):
        printed = False
        s1 = s2 = 0
        for t, delta1, delta2 in self.delta:
            if delta1 or delta2:
                if not printed:
                    print (
                        '    Leak details, changes in instances and refcounts'
                        ' by type/class:')
                    print("    %-55s %6s %6s" % ('type/class', 'insts', 'refs'))
                    print("    %-55s %6s %6s" % ('-' * 55, '-----', '----'))
                    printed = True
                print("    %-55s %6d %6d" % (t, delta1, delta2))
                s1 += delta1
                s2 += delta2

        if printed:
            print("    %-55s %6s %6s" % ('-' * 55, '-----', '----'))
            print("    %-55s %6s %6s" % ('total', s1, s2))


        self.delta = None


def type_or_class_title(t):
    module = getattr(t, '__module__', '__builtin__')
    if module == '__builtin__':
        return t.__name__
    return "%s.%s" % (module, t.__name__)
