# Copyright (c) 2015 Danyil Bohdan
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
variable storage {}
proc initialize {channelId mode} {
variable storage
dict set storage $channelId data {}
dict set storage $channelId ticktock 0 ;# read phase counter
return [list initialize finalize watch read write]
}
proc finalize {channelId} {
variable storage
dict unset storage $channelId
}
proc watch {channelId eventspec} {}
proc read {channelId count} {
# We ignore $count.
variable storage
# Force values to be read one at a time from the channel.
if {[TickTock $channelId] == 0} {
set chanData [dict get $storage $channelId data]
dict set storage $channelId data [lrange $chanData 1 end]
return [lindex $chanData 0]
} else {
error EAGAIN
}
}
proc write {channelId data} {
variable storage
set chanData [dict get $storage $channelId data]
dict set storage $channelId data [list {*}$chanData $data]
return [string length $data]
}
# "Private" API.
# Change the "ticktock" value associated with $channelId form 0 to 1 or from
# 0 to 1.
proc TickTock {channelId} {
variable storage
set ticktock [dict get $storage $channelId ticktock]
dict set storage $channelId ticktock [expr {!$ticktock}]
return $ticktock
}