# 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 = *

  [blackbox]

  track = command, commandfinish, commandexception, exthook, pythonhook

  [blackbox]

  track = incoming

"""

from mercurial import util, cmdutil

from mercurial.i18n import _

import os, re

cmdtable = {}

command = cmdutil.command(cmdtable)

testedwith = 'internal'

lastblackbox = None

def wrapui(ui):

    class blackboxui(ui.__class__):

        @util.propertycache

        def track(self):

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

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

            global lastblackbox

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

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

                return

            if util.safehasattr(self, '_blackbox'):

                blackbox = self._blackbox

            else:

                # certain ui instances exist outside the context of

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

                # was seen.

                blackbox = lastblackbox

            if blackbox:

                date = util.datestr(None, '%Y/%m/%d %H:%M:%S')

                user = util.getuser()

                formattedmsg = msg[0] % msg[1:]

                try:

                    blackbox.write('%s %s> %s' % (date, user, formattedmsg))

                except IOError, err:

                    self.debug('warning: cannot write to blackbox.log: %s\n' %

                               err.strerror)

                lastblackbox = blackbox

        def setrepo(self, repo):

            try:

                self._blackbox = repo.opener('blackbox.log', 'a')

                self.debug('warning: cannot write to blackbox.log: %s\n' %

                           err.strerror)

                self._blackbox = None

    ui.__class__ = 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

    ui.setrepo(repo)

@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 os.path.exists(repo.join('blackbox.log')):

        return

    limit = opts.get('limit')

    blackbox = repo.opener('blackbox.log', 'r')

    lines = blackbox.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)))