# blackbox.py - log repository events to a file for post-mortem debugging

#

# Copyright 2010 Nicolas Dumazet

# Copyright 2013 Facebook, Inc.

#

# This software may be used and distributed according to the terms of the

# GNU General Public License version 2 or any later version.

"""log repository events to a blackbox for debugging

Logs event information to .hg/blackbox.log to help debug and diagnose problems.

The events that get logged can be configured via the blackbox.track config key.

Examples::

  [blackbox]

  track = *

  # dirty is *EXPENSIVE* (slow);

  # each log entry indicates `+` if the repository is dirty, like :hg:`id`.

  dirty = True

  # record the source of log messages

  logsource = True

  [blackbox]

  track = command, commandfinish, commandexception, exthook, pythonhook

  [blackbox]

  track = incoming

  [blackbox]

  # limit the size of a log file

  maxsize = 1.5 MB

  # rotate up to N log files when the current one gets too big

  maxfiles = 3

"""

from __future__ import absolute_import

import errno

import re

from mercurial.i18n import _

from mercurial.node import hex

from mercurial import (

    registrar,

    ui as uimod,

    util,

)

# Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for

# extensions which SHIP WITH MERCURIAL. Non-mainline extensions should

# be specifying the version(s) of Mercurial they are tested with, or

# leave the attribute unspecified.

testedwith = 'ships-with-hg-core'

cmdtable = {}

command = registrar.command(cmdtable)

configtable = {}

configitem = registrar.configitem(configtable)

configitem('blackbox', 'dirty',

    default=False,

)

configitem('blackbox', 'maxsize',

    default='1 MB',

)

configitem('blackbox', 'logsource',

    default=False,

)

lastui = None

def wrapui(ui):

    class blackboxui(ui.__class__):

        @property

        def _bbvfs(self):

            repo = getattr(self, '_bbrepo', None)

            if repo:

                return repo.vfs

        @util.propertycache

        def track(self):

            return self.configlist('blackbox', 'track', ['*'])

        def _openlogfile(self):

            def rotate(oldpath, newpath):

                try:

                    self._bbvfs.unlink(newpath)

                except OSError as err:

                    if err.errno != errno.ENOENT:

                        self.debug("warning: cannot remove '%s': %s\n" %

                                   (newpath, err.strerror))

                try:

                    if newpath:

                        self._bbvfs.rename(oldpath, newpath)

                except OSError as err:

                    if err.errno != errno.ENOENT:

                        self.debug("warning: cannot rename '%s' to '%s': %s\n" %

                                   (newpath, oldpath, err.strerror))

            maxsize = self.configbytes('blackbox', 'maxsize')

            name = 'blackbox.log'

            if maxsize > 0:

                try:

                    st = self._bbvfs.stat(name)

                except OSError:

                    pass

                else:

                    if st.st_size >= maxsize:

                        path = self._bbvfs.join(name)

                        maxfiles = self.configint('blackbox', 'maxfiles', 7)

                        for i in xrange(maxfiles - 1, 1, -1):

                            rotate(oldpath='%s.%d' % (path, i - 1),

                                   newpath='%s.%d' % (path, i))

                        rotate(oldpath=path,

                               newpath=maxfiles > 0 and path + '.1')

            return self._bbvfs(name, 'a')

        def log(self, event, *msg, **opts):

            global lastui

            super(blackboxui, self).log(event, *msg, **opts)

            if not '*' in self.track and not event in self.track:

                return

            if self._bbvfs:

                ui = self

            else:

                # certain ui instances exist outside the context of

                # a repo, so just default to the last blackbox that

                # was seen.

                ui = lastui

            if not ui:

                return

            repo = getattr(ui, '_bbrepo', None)

            if not lastui or repo:

                lastui = ui

            if getattr(ui, '_bbinlog', False):

                # recursion and failure guard

                return

            try:

        def setrepo(self, repo):

            self._bbrepo = repo

    ui.__class__ = blackboxui

    uimod.ui = blackboxui

def uisetup(ui):

    wrapui(ui)

def reposetup(ui, repo):

    # During 'hg pull' a httppeer repo is created to represent the remote repo.

    # It doesn't have a .hg directory to put a blackbox in, so we don't do

    # the blackbox setup for it.

    if not repo.local():

        return

    if util.safehasattr(ui, 'setrepo'):

        ui.setrepo(repo)

    repo._wlockfreeprefix.add('blackbox.log')

@command('^blackbox',

    [('l', 'limit', 10, _('the number of events to show')),

    ],

    _('hg blackbox [OPTION]...'))

def blackbox(ui, repo, *revs, **opts):

    '''view the recent repository events

    '''

    if not repo.vfs.exists('blackbox.log'):

        return

    limit = opts.get('limit')

    fp = repo.vfs('blackbox.log', 'r')

    lines = fp.read().split('\n')

    count = 0

    output = []

    for line in reversed(lines):

        if count >= limit:

            break

        # count the commands by matching lines like: 2013/01/23 19:13:36 root>

        if re.match('^\d{4}/\d{2}/\d{2} \d{2}:\d{2}:\d{2} .*> .*', line):

            count += 1

        output.append(line)

    ui.status('\n'.join(reversed(output)))