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########## datastate.tcl
# This file contains core routines for handling the persistent
# data with timeouts.
#
# This file is part of SAUCE, a very picky anti-spam receiver-SMTP.
# SAUCE is Copyright (C) 1997-2003 Ian Jackson
#
# 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, 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
#
# $Id: datastate.tcl,v 1.15 2006/04/03 01:02:07 ian Exp $
# This routine maintains permanent database(s) of information about
# key(s). Each database maps a key to a state value. The state
# values are defined by the caller. The states may time out, and be
# replaced by other states, as defined by the caller.
# We use a cdb-wr from chiark-tcl. Keys are the key as supplied to
# ds_set (possibly quoted if specified during bind).
# Values are of the form
# 0xHHHHHHHHHHHHHHHH ultimate-value 0xHHHHHHHHHHHHHHHH penultimate-value...
# ... 0xHHHHHHHHHHHHHHHH current-value
# The variables used internally are:
# ds__cdbwr.DB cdb-wr handle
# ds__perm.DB.(KEY) Permanent settings (VALUE only)
# ds__quotekey.DB 0 or 1
# ds__regexp.DB Regexp which values must match
load chiark_tcl_cdb-1.so
#---------- general utilities ----------
proc ds__proctimeouts {db telemvar now} {
upvar 1 $telemvar telem
set changed 0
debug 4 ds__proctimeouts $db at $now $telem ...
while {[llength $telem] && [lindex $telem end-1] < $now} {
set telem [lrange $telem 0 end-2]
set changed 1
}
debug 3 ds__proctimeouts $db at $now $telem !
return $changed
}
proc ds__setentry {db key telem} {
upvar #0 ds__cdbwr.$db cdb
if {[llength $telem]} {
debug 3 ds__setentry $db $key := $telem
cdb-wr update $cdb $key $telem
} else {
debug 3 ds__setentry $db $key :=<>
cdb-wr delete $cdb $key
}
}
proc ds__checkvalue {db value} {
upvar #0 ds__regexp.$db regexp
if {![regexp -- $regexp $value]} { error "bad db value $value for $db" }
}
proc ds__key_quote {key} {
set keyquoted {}
while {[regexp -nocase {^([-=_+@.%0-9a-z]*)([^-=_+@.%0-9a-z])(.*)$} \
$key dummy l ch key]} {
binary scan $ch H* hex
append keyquoted $l {\x} $hex
}
append keyquoted $key
return $keyquoted
}
proc ds__key_quote_maybe {db keyvar} {
upvar #0 ds__quotekey.$db doquote
if {!$doquote} return
upvar 1 $keyvar key
set key [ds__key_quote $key]
}
#---------- retrieval ----------
proc ds_get {db key} {
# Returns the current value in DB of KEY. If the key is not
# found (or has expired), returns `unknown'.
ds__key_quote_maybe $db key
upvar #0 ds__perm.$db.($key) perm
upvar #0 ds__cdbwr.$db cdb
if {[info exists perm]} {
debug 2 ds_get $db $key ?.=> $perm
return $perm
}
set telem [cdb-wr lookup $cdb $key {}]
if {[ds__proctimeouts $db telem [clock seconds]]} {
ds__setentry $db $key $telem
}
if {[llength $telem]} {
set value [lindex $telem end]
ds__checkvalue $db $value
debug 2 ds_get $db $key ?=> $value
} else {
set value unknown
debug 2 ds_get $db $key ?=>- $value
}
return $value
}
#---------- updating ----------
proc ds_set {db key args} {
# Sets, in DB, the value of KEY. The remaining ARGS should come
# in pairs VALUE TIMEOUT, where VALUE is the value, and TIMEOUT is
# the duration in seconds for which the value should hold. VALUEs
# should consist of alphanumerics.
ds__key_quote_maybe $db key
upvar #0 ds__perm.$db.($key) perm
set now [clock seconds]
if {[info exists perm]} {
debug 2 ds_set $db $key (:=$args) .= $perm
return
}
debug 2 ds_set $db at $now $key := $args
set telem {}
foreach {value timeout} $args {
ds__checkvalue $db $value
incr timeout $now
set telem [lreplace $telem 0 -1 [format 0x%016x $timeout] $value]
}
ds__proctimeouts $db telem $now
ds__setentry $db $key $telem
}
proc ds_setforever {db key value} {
# Sets, in DB, the value of KEY to VALUE, forever. This is not
# recorded in any database files - it is assumed to be the
# result of static configuration.
ds__key_quote_maybe $db key
upvar #0 ds__perm.$db.($key) perm
debug 2 ds_setforever $db $key :=. $value
ds__checkvalue $db $value
set perm $value
}
#---------- binding and machinery ----------
proc ds__oninfo {db args} {
log notice "$db cdb-wr $args"
}
proc ds__clockseconds {} { format 0x%016x [clock seconds] }
proc ds_bind {db prefix regexp quotekey} {
# Binds the database DB to files with prefix FILEPREFIX.
# This will load the database, and it will also cause
# updates to be recorded there. FILEPREFIX is passed to cdb-wr.
# Values must match REGEXP (though ds_get may also return `unknown').
set now [clock seconds]
debug 3 ds_bind $db $prefix at $now
upvar #0 ds__cdbwr.$db cdb
foreach v {regexp quotekey} {
upvar #0 ds__${v}.$db toset
set toset [set $v]
}
set cdb [cdb-wr open $prefix [list ds__oninfo $db] ds__clockseconds]
}
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