#!/usr/bin/env python

#

# Copyright (C) 2010 Mozilla Foundation

# Copyright (C) 2010 Symbian Foundation

#

# 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

# Initial Contributors:

#  Pat Downey <patd@symbian.org>

# 

# Contributors:

#  Your name here?

#

# Description:

#

# An extension to mercurial that adds the ability to specify a blacklist for 

# a repository. That is to deny a changeset from being pushed/pulled/unbundled

# if it matches one of a set of patterns.

#

# At present it can deny nodes based on their changeset id, a regular expression

# matched against the user field, or a regular expression matched against the

# changeset's file list.

#

# Note: With the regular expression rules, if you want to match a string anywhere

# with in a string, e.g. create a rule against files within directories called 

# 'internal' the rule would need to be ..*/internal/.*'. That is you need to be 

# explicit in specifying a set of any characters otherwise it will perform a

# direct string comparison. #

#

# Requires sqlite extension (included in python 2.5 onwards)

#  * Available for python 2.4 in python-sqlite2 package on RHEL5.2+

#

# Ideas for implementation came strongly from:

# http://hg.mozilla.org/users/bsmedberg_mozilla.com/hghooks/file/tip/mozhghooks/pushlog.py

#

#

'''manage repository changeset blacklist

'''

from mercurial import demandimport

demandimport.disable()

try:

    import sqlite3 as sqlite

except ImportError:

    from pysqlite2 import dbapi2 as sqlite

demandimport.enable()

import binascii

import os

import os.path

import re

import stat

import sys

import time

from datetime import datetime

# changeset identifier 12-40 hex chars 

NODE_RE='^[0-9|a-f]{12,40}'

def blacklist(ui,repo,*args,**opts):

  '''manage repository changeset blacklist

  This extension is used to manage a blacklist for the repository.

  Can blacklist changesets by changeset id, and regular expressions against

  the user field of a changeset and also a changesets file list.

  Current rules can be viewed using the [-l|--list] operation.

  Each modification to a blacklist is logged. These can be viewed using the 

  --auditlog operation.

  Each time a changeset is blocked/denied it's logged. These can be viewed

  using the --blocklog operation.

  Types of changeset blacklist rules can be defined implicitly or explicitly:

    If a rule definition contains between 12 and 40 hexadecimal characters 

    it is assumed to be a rule matched against changeset id. Can be set 

    explicitly set with the -n flag to the --add operation.

    If a rule definition contains a '@' it is assumed to be a rule matched 

    against a changeset's user property. Can be set explicitly with 

    the -u flag to the --add operation.

    Otherwise the rule is assumed to be matched against a changeset's file 

    list. Can be set explicitly with the -f flag to the --add operation.

    When this extension is enabled a hook is also added to the 

    'pretxnchangegroup' action that will block any incoming changesets 

    (via pull/push/unbundle) if they are blacklisted.

    It won't block any local commits.

  '''

  conn = openconn(ui, repo )      

  if 'list' in opts and opts['list'] :

    listblacklistrule(ui,conn,args,opts)

  elif 'blocklog' in opts and opts['blocklog'] :

    listblacklistblocklog(ui,conn,args,opts)

  elif 'auditlog' in opts and opts['auditlog'] :

    listblacklistauditlog(ui,conn,args,opts)

  elif 'enable' in opts and opts['enable'] :

    enableblacklistrule(ui,conn,args,opts) 

  elif 'disable' in opts and opts['disable'] :

    disableblacklistrule(ui,conn,args,opts)

  elif 'remove' in opts and opts['remove'] :

    removeblacklistrule(ui,conn,args,opts)

  elif 'add' in opts and opts['add'] :

    addblacklistrule(ui,conn,args,opts)

  else :

    ui.warn( 'invalid operation specified\n' )

  conn.close( )  

####### Database setup methods

# this part derived from mozilla's pushlog.py hook

def openconn(ui,repo):

  blacklistdb = os.path.join(repo.path, 'blacklist.db')

  createdb = False

  if not os.path.exists(blacklistdb):

    createdb = True

  conn = sqlite.connect(blacklistdb)

  if not createdb and not schemaexists(conn):

    createdb = True

  if createdb:

    createblacklistdb(ui,conn)

    st = os.stat(blacklistdb)

    os.chmod(blacklistdb, st.st_mode | stat.S_IWGRP)

  return conn

# Derived from mozilla's pushlog hook

def schemaexists(conn):

    return 3 == conn.execute("SELECT COUNT(*) FROM SQLITE_MASTER WHERE name IN ( ?, ?, ?)" , ['blacklist_rule','blacklist_auditlog','blacklist_blocklog']).fetchone()[0]

# Derived from mozilla's pushlog hook

def createblacklistdb(ui,conn):

    # record of different blacklist rule, type should be either 'node' or 'file' or 'user'

    # 'node' - compare pattern with changeset identifier

    # 'file' - used as regular expression against changeset file manifest

    # 'user' - used as regular expression against changeset author/user

    # (id,pattern,type,enabled)

    conn.execute("CREATE TABLE IF NOT EXISTS blacklist_rule (id INTEGER PRIMARY KEY AUTOINCREMENT, pattern TEXT, type TEXT, enabled INTEGER,comment TEXT)")

    conn.execute("CREATE UNIQUE INDEX IF NOT EXISTS blacklist_rule_idx ON blacklist_rule (pattern,type)" )

    # records additions and modifications to the blacklist_rule table

    # (id, operation, rule_id, user, date, comment)

    conn.execute("CREATE TABLE IF NOT EXISTS blacklist_auditlog (id INTEGER PRIMARY KEY AUTOINCREMENT, operation TEXT, rule_id INTEGER, user TEXT, date INTEGER, comment TEXT)")

    conn.execute("CREATE INDEX IF NOT EXISTS blacklist_auditlog_rule_idx ON blacklist_auditlog (rule_id)" )

    # log attempted pushes and the http users trying to push a blocked changeset

    # (id,rule_id,cset_id, cset_user, cset_desc, user,date)

    conn.execute("CREATE TABLE IF NOT EXISTS blacklist_blocklog (id INTEGER PRIMARY KEY AUTOINCREMENT, rule_id INTEGER, cset_id TEXT, cset_user TEXT, cset_desc TEXT, user TEXT, date INTEGER)")

    conn.execute("CREATE INDEX IF NOT EXISTS blacklist_blocklog_rule_idx ON blacklist_blocklog (rule_id)" )

    conn.commit()

# Methods for extension commands      

def __getblacklistruletype( ui, pattern, opts ):

  type=None

  if opts['nodeType'] :

    type = 'node'

  elif opts['fileType'] :

    type = 'file'

  elif opts['userType'] :

    type = 'user'

  # try and work out type of blacklist if none specified

  # default to regexp

  if type == None :

    if re.match( NODE_RE, pattern ) :

      type = 'node'

    elif '@' in pattern :

      type = 'user'

    else :

      type = 'file'

    ui.note( 'type implicitly set to \'%s\'\n' % type )  

  return type

def addblacklistrule(ui,conn,args,opts):

  ret = 1

  if len(args) == 1 :

    createrule = True

    pattern = args[0]

    type = __getblacklistruletype( ui, pattern, opts )

    if type == 'node' :

      # if pattern has been specified as a node type

      # check that pattern is a valid node

      if not re.match( NODE_RE, pattern ) :

        ui.warn( 'node should be 12 or 40 characters.\n' )

        createrule = False 

    if createrule :

      comment = None

      if 'desc' in opts and opts['desc'] :

        if opts['desc'] != '' :

          comment = opts['desc']

      insertblacklistrule(ui,conn,pattern,type, comment=comment)

  else :

    ui.warn( 'missing pattern argument.\n' )

  return ret      

def removeblacklistrule(ui,conn,args,opts):

  if len(args) == 1 :

    deleteblacklistrule(ui,conn,args[0])

  else :

    ui.warn( 'rule id argument required.\n' )

  return 0

def disableblacklistrule(ui,conn,args,opts):

  if len(args) == 1 :

    updateblacklistrule(ui,conn,args[0],False)

  else :

    ui.warn( 'rule id argument required.\n' )

  return 0    

def enableblacklistrule(ui,conn,args,opts):

  if len(args) == 1 :

    updateblacklistrule(ui,conn,args[0],True)

  else :

    ui.warn( 'rule id argument required.\n' )

  return 0    

def listblacklistrule(ui,conn,args,opts):

  if len(args) in (0,1) :

    res = selectblacklistrule(ui,conn,args)

    printblacklist(ui,res)

  else :

    ui.warn( 'too many arguments.\n' )

  return 0

def listblacklistauditlog(ui,conn,args,opts):

  if len(args) in (0,1) :

    res = selectblacklistauditlog(ui, conn, args )

    printauditlog(ui,res)

  else :

    ui.warn( 'too many arguments.\n' )

  return 0

def listblacklistblocklog(ui,conn,args,opts):

  if len(args) in (0,1) :

    res = selectblacklistblocklog(ui, conn, args )

    printblocklog(ui,res)

  else :

    ui.warn( 'too many arguments.\n' )

  return 0

def insertblacklistaudit(ui, conn, operation, rule_id, comment=None ):

  user = __getenvuser( )

  audit_date = int(time.time())

  audit_sql = 'INSERT INTO blacklist_auditlog ( operation, rule_id, user, date, comment ) VALUES ( ?, ?, ?, ?, ? )'

  conn.execute( audit_sql, (operation, rule_id, user, audit_date, comment ) )

def insertblacklistrule(ui, conn, pattern, type, enabled=True, comment=None):

  rule_sql = 'INSERT INTO blacklist_rule ( pattern, type, enabled,comment ) VALUES ( ?, ?, ?, ? )'

  res = conn.execute( rule_sql, (pattern,type,enabled,comment) )

  rule_id= res.lastrowid

  insertblacklistaudit(ui, conn, 'add', rule_id,comment=comment )

  conn.commit( )

def __getenvuser( ):

  # look at REMOTE_USER first  

  # then look at LOGUSER

  # then look at USER

  for e in ['REMOTE_USER','SUDO_USER','LOGUSER','USER'] :

    if e in os.environ :

      user = '%s:%s' %( e, os.environ.get( e ) )

      break

  return user

def insertblacklistblocklog( ui, conn, rule, ctx ):

  # (id, rule_id, user, date)

  rule_id=rule[0]

  log_user = __getenvuser( )

  audit_date = int(time.time())

  ctx_node = binascii.hexlify(ctx.node())

  ctx_user = ctx.user()

  ctx_desc = ctx.description()

  log_sql = 'INSERT INTO blacklist_blocklog (rule_id,user,date,cset_id,cset_user,cset_desc) VALUES (?,?,?,?,?,?)'

  conn.execute( log_sql, (rule_id,log_user,audit_date, ctx_node, ctx_user, ctx_desc))

  conn.commit()    

def updateblacklistrule(ui, conn, rule_id, enabled):

  rule_sql = 'UPDATE blacklist_rule SET enabled=? WHERE id=?'

  conn.execute( rule_sql, [enabled, rule_id] )

  insertblacklistaudit(ui, conn, 'update', rule_id, 'enabled=%s' % enabled )

  conn.commit( )

def deleteblacklistrule(ui, conn, rule_id ):

  if rule_id != None :

    res = selectblacklistrule(ui, conn, rule_id )

    processed = False

    for (id,pattern,type,enabled,comment) in res :

      comment = 'deleted: pattern=%s, type=%s, enabled=%s' % (pattern, type, enabled)

      rule_sql = 'DELETE FROM blacklist_rule WHERE id=?'

      conn.execute( rule_sql, [rule_id] )

      insertblacklistaudit(ui, conn, 'delete', rule_id, comment)      

      conn.commit( )

      processed = True

    if not processed :

      ui.warn( 'no matching blacklist rule found with id %s\n' % rule_id )

  else :

    ui.warn( 'no rule id specified\n' )

def selectblacklistrule(ui, conn, rule_id ):

  # (id, operation, rule_id, user, date, comment)

  if rule_id :

    rule_sql = 'SELECT id,pattern,type,enabled,comment FROM blacklist_rule WHERE id=? ORDER BY id ASC'

    res = conn.execute( rule_sql, rule_id )

  else :

    rule_sql = 'SELECT id,pattern,type,enabled,comment FROM blacklist_rule ORDER BY id ASC'

    res = conn.execute( rule_sql )

  return res  

def selectblacklistauditlog(ui,conn,rule_id=None) :

  # (id, operation, rule_id, user, date, comment)

  if rule_id :

    rule_sql = 'SELECT id,operation,rule_id,user,date,comment FROM blacklist_auditlog WHERE rule_id=? ORDER BY date ASC'

    res = conn.execute( rule_sql, rule_id )

  else :

    rule_sql = 'SELECT id,operation,rule_id,user,date,comment FROM blacklist_auditlog ORDER BY date ASC'

    res = conn.execute( rule_sql )

  return res

def selectblacklistblocklog(ui,conn,rule_id=None) :

  # (id, rule_id, node, user, date)

  if rule_id :

    rule_sql = 'SELECT id,rule_id,cset_id,cset_user,cset_desc,user,date FROM blacklist_blocklog WHERE rule_id=? ORDER BY date ASC'

    res = conn.execute( rule_sql, rule_id )

  else :

    rule_sql = 'SELECT id,rule_id,cset_id,cset_user,cset_desc,user,date FROM blacklist_blocklog ORDER BY date ASC'

    res = conn.execute( rule_sql )

  return res  

def printblacklist(ui,res):

  for r in res :

    (id,pattern,type,enabled,comment) = r  

    if enabled == 1 :

      enabled = True

    elif enabled == 0 :

      enabled = False

    ui.write( 'rule:     %d:%s\n' % (id,type) )

    ui.write( 'pattern:  %s\n' % pattern )

    ui.write( 'enabled:  %s\n' % enabled )

    if comment :

      ui.write( 'comment:  %s\n' % comment )

    ui.write( '\n' )

def printauditlog(ui,res):

  for r in res :

    (id, operation, rule_id, user, date, comment) = r

    date = datetime.utcfromtimestamp(date).isoformat()  

    if not comment :

      comment = '' 

    ui.write( 'date:      %s\n' % date )

    ui.write( 'operation: %s\n' % operation )

    ui.write( 'user:      %s\n' % user )

    ui.write( 'rule:      %s\n' % rule_id )

    ui.write( 'comment:   %s\n' % comment )

    ui.write( '\n' )

def printblocklog(ui,res):

  for r in res :

    (id, rule_id, cset_id, cset_user, cset_desc, user, date) = r

    date = datetime.utcfromtimestamp(date).isoformat()  

    ui.write( 'cset:      %s\n' % cset_id )

    ui.write( 'cset-user: %s\n' % cset_user)

    ui.write( 'cset-desc: %s\n' % cset_desc )

    ui.write( 'rule:      %s\n' % rule_id )

    ui.write( 'date:      %s\n' % date )

    ui.write( 'user:      %s\n' % user )

    ui.write( '\n' )

# Hook specific functions follow

def excludecsetbyfile(ctx,pattern):

  exclude = False

  file_re = re.compile( '%s' % pattern, re.I )

  for f in ctx.files() :

    if file_re.match( f ) :

      exclude = True

      break

  return exclude

def excludecsetbynode(ctx,pattern):

  exclude = False

  node = binascii.hexlify(ctx.node())

  if node.startswith( pattern ) :

    exclude = True

  return exclude

def excludecsetbyuser(ctx,pattern):

  exclude = False

  userStr = ctx.user()

  user_re = re.compile( '^.*%s.*$' % pattern, re.I )

  if user_re.match( userStr ) :

    exclude = True

  return exclude  

def excludeblacklistcset(ui,conn,ctx):

  bl_sql = 'SELECT id,pattern,type FROM blacklist_rule WHERE enabled=1'

  res = conn.execute( bl_sql )

  (exclude,rule) = (False,None)

  for (id,pattern,type) in res :

    if type == 'node' :

      exclude = excludecsetbynode(ctx,pattern)

    elif type == 'user' :

      exclude = excludecsetbyuser(ctx,pattern)

    elif type == 'file' :

      exclude = excludecsetbyfile(ctx,pattern)

    else :

      ui.warn('unrecognised rule type \'%s\'' % type )

    if exclude :

      rule = (id,pattern,type)

      break

  return (exclude,rule)

# The hook method that is used to block bad changesets from being introduced 

# to the current repository

def pretxnchangegroup(ui,repo,hooktype,node,**args):

  start = repo[node].rev()

  end = len(repo)

  conn = openconn(ui, repo )

  blocked = False

  for rev in xrange(start, end):

    ctx = repo[rev]

    (blocked,rule) = excludeblacklistcset( ui, conn, ctx)

    if blocked :

      insertblacklistblocklog( ui, conn, rule, ctx )

      (id,pattern,type) = rule

      ui.write( 'blocked: cset %s in changegroup blocked by blacklist\n' % str(ctx) )

      ui.write( 'blocked-reason: %s matched against \'%s\'\n' % ( type,pattern ))

      break

  conn.close( )    

  return blocked

def setupblacklisthook(ui):

  ui.setconfig('hooks', 'pretxnchangegroup.blacklist', pretxnchangegroup)

def reposetup(ui,repo):

  # print 'in blacklist reposetup'

  setupblacklisthook( ui )

def uisetup(ui):

  # print 'in blacklist uisetup'

  setupblacklisthook( ui )

cmdtable = {

            'blacklist': (blacklist,