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#################################################################
# connect.tcl - callback based layer on top of socket
#
# Copyright (C) 2002 Mark Patton
#
# 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., 675 Mass Ave, Cambridge, MA 02139, USA.
###################################################################
# connect starts a socket connection to a host. It uses the Thread extension
# if present. The actual connection is managed through a callback interface.
# The attempt event in the callback gives a token that can be used with
# connect_cancel to stop the connection attempt
# args has these switches
# -timeout ms max time to wait for a connection, defaults to 10000
# -max_attempts num number of connection attempts to make, defaults to 1
# -attempt_wait ms time to wait after a timeout to attempt reconnection
# -thread bool use threads, defaults to true if Thread package present
# callback sig is {data event args} where the events are:
# event types:
# attempt tok num
# failure msg
# timeout
# success chan
set _con(script_loaded) 0
set _con(seq) 0
proc connect {host port callback data args} {
global _con
array set arg [list -max_attempts 1 -timeout 10000 -attempt_wait 2000]
array set arg $args
set arg(-thread) \
[expr {$arg(-thread) && ![catch {package require Thread}]}]
set id [incr _con(seq)]
set script [list _connect $id $host $port $callback $data \
$arg(-max_attempts) $arg(-timeout) $arg(-attempt_wait)]
if {$arg(-thread)} {
set thr_id [thread::create]
lappend script [list [thread::id] $thr_id]
thread::send -async $thr_id $_con(script)
thread::send -async $thr_id $script
} else {
if {!$_con(script_loaded)} {
eval $_con(script)
set _con(script_loaded) 1
}
eval $script
}
return
}
proc connect_cancel {tok} {
global _con
foreach {id thr_id} $tok {}
if {[llength $tok] == 2} {
thread::send -async $thr_id thread::exit
} else {
catch {
after cancel $_con($id,timeout_id)
close $_con($id,chan)
}
array unset _con $id,*
}
}
set _con(script) {
proc _connect_cleanup {id} {
global _con
if {$_con($id,slave_thread)} {
thread::exit
}
array unset _con $id,*
}
proc _connect_callback {id args} {
global _con
set script [linsert $args 0 $_con($id,callback) $_con($id,data)]
if {$_con($id,slave_thread)} {
thread::send -async $_con($id,master) $script
} else {
eval $script
}
}
proc _connect_timeout {id} {
global _con
close $_con($id,chan)
_connect_callback $id timeout
if {$_con($id,attempt) < $_con($id,max_attempts)} {
incr _con($id,attempt)
after $_con($id,attempt_wait) [list _connect_real $id]
} else {
_connect_cleanup $id
}
}
proc _connect_complete {id} {
global _con
after cancel $_con($id,timeout_id)
fileevent $_con($id,chan) readable ""
set err [fconfigure $_con($id,chan) -error]
if {$err eq ""} {
if {$_con($id,slave_thread)} {
thread::transfer $_con($id,master) $_con($id,chan)
}
_connect_callback $id success $_con($id,chan)
} else {
catch {close $_con($id,chan)}
_connect_callback $id failure $err
}
_connect_cleanup $id
}
proc _connect_real {id} {
global _con
set tok [list $id]
if {$_con($id,slave_thread)} {
lappend tok $_con($id,slave)
}
_connect_callback $id attempt $tok $_con($id,attempt)
if {![info exists _con($id,timeout)]} {
# canceled in the callback
return
}
set _con($id,timeout_id) \
[after $_con($id,timeout) [list _connect_timeout $id]]
set error [catch {socket -async $_con($id,host) $_con($id,port)} res]
if {$error} {
after cancel $_con($id,timeout_id)
_connect_callback $id failure $res
_connect_cleanup $id
} else {
set _con($id,chan) $res
fileevent $_con($id,chan) readable [list _connect_complete $id]
}
}
proc _connect {id host port cb data attempts timeout wait {thrd_ids {}}} {
global _con
array set _con [list $id,host $host $id,port $port $id,attempt 1 \
$id,timeout $timeout $id,max_attempts $attempts \
$id,callback $cb $id,data $data $id,attempt_wait $wait \
$id,master [lindex $thrd_ids 0] \
$id,slave [lindex $thrd_ids 1] \
$id,slave_thread [llength $thrd_ids]]
_connect_real $id
}
}
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