[3330] | 1 | # -*- mode: tcl; indent-tabs-mode: nil -*- |
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[1] | 2 | # ---------------------------------------------------------------------- |
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| 3 | # COMPONENT: dispatcher - central notification mechanism |
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| 4 | # |
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| 5 | # The DispatchObj is used within other objects to manage events that |
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| 6 | # the object sends to itself or other clients. Each event type |
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| 7 | # must first be registered via the "register" method. After that, |
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| 8 | # an event can be dispatched by calling the "event" method. Clients |
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| 9 | # can bind to the various event types by registering a callback via |
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| 10 | # the "dispatch" method. |
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| 11 | # |
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| 12 | # The Dispatcher base class provides a foundation for objects that |
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| 13 | # use the DispatchObj internally. |
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| 14 | # ====================================================================== |
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| 15 | # AUTHOR: Michael McLennan, Purdue University |
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[3177] | 16 | # Copyright (c) 2004-2012 HUBzero Foundation, LLC |
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[115] | 17 | # |
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| 18 | # See the file "license.terms" for information on usage and |
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| 19 | # redistribution of this file, and for a DISCLAIMER OF ALL WARRANTIES. |
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[1] | 20 | # ====================================================================== |
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| 21 | package require Itcl |
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| 22 | |
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| 23 | namespace eval Rappture { # forward declaration } |
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| 24 | |
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| 25 | proc Rappture::dispatcher {varName} { |
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| 26 | upvar $varName obj |
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| 27 | set obj [Rappture::DispatchObj ::#auto] |
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| 28 | trace variable obj u "[list rename $obj {}]; list" |
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| 29 | } |
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| 30 | |
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| 31 | itcl::class Rappture::DispatchObj { |
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| 32 | constructor {} { # defined below } |
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| 33 | destructor { # defined below } |
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| 34 | |
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| 35 | public method register {args} |
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| 36 | public method dispatch {option args} |
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| 37 | public method event {name args} |
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| 38 | public method cancel {args} |
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| 39 | public method ispending {name} |
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| 40 | |
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| 41 | protected method _send {event caller {arglist ""}} |
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| 42 | |
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| 43 | private variable _event2clients ;# maps !event => clients |
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| 44 | private variable _event2datacb ;# maps !event => data callback |
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| 45 | private variable _dispatch ;# maps !event/client => callback |
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| 46 | private variable _extraargs ;# extra args for dispatch calls |
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| 47 | } |
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[1929] | 48 | |
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[1] | 49 | # ---------------------------------------------------------------------- |
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| 50 | # CONSTRUCTOR |
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| 51 | # ---------------------------------------------------------------------- |
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| 52 | itcl::body Rappture::DispatchObj::constructor {} { |
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| 53 | # nothing to do |
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| 54 | } |
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[1929] | 55 | |
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[1] | 56 | # ---------------------------------------------------------------------- |
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| 57 | # DESTRUCTOR |
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| 58 | # ---------------------------------------------------------------------- |
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| 59 | itcl::body Rappture::DispatchObj::destructor {} { |
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| 60 | eval cancel [array names _event2clients] |
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| 61 | } |
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| 62 | |
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| 63 | # ---------------------------------------------------------------------- |
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| 64 | # USAGE: register !event ?dataCallback? |
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| 65 | # |
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| 66 | # Clients use this to register new event types with this dispatcher. |
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| 67 | # Once registered, each !event name can be used in the "dispatch" |
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| 68 | # method to bind to the event, and in the "event" method to raise |
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| 69 | # the event. If the optional dataCallback is supplied, then it is |
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| 70 | # invoked whenever the event is triggered to generate event data |
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| 71 | # that gets passed along to the various dispatch callbacks. |
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| 72 | # ---------------------------------------------------------------------- |
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| 73 | itcl::body Rappture::DispatchObj::register {name {datacb ""}} { |
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| 74 | if {![regexp {^![-_a-zA-Z0-9]} $name]} { |
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[1929] | 75 | error "bad name \"$name\": should be !name" |
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[1] | 76 | } |
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| 77 | if {[info exists _event2clients($name)]} { |
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[1929] | 78 | error "event \"$name\" already exists" |
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[1] | 79 | } |
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| 80 | set _event2clients($name) "" |
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| 81 | set _event2datacb($name) $datacb |
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| 82 | } |
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| 83 | |
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| 84 | # ---------------------------------------------------------------------- |
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| 85 | # USAGE: dispatch caller ?-now? ?!event ...? ?callback? |
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| 86 | # |
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| 87 | # Clients use this to query binding information, or to bind a callback |
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| 88 | # to one or more of the !events recognized by this object. |
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| 89 | # |
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| 90 | # With no args, this returns a list of all events that are currently |
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| 91 | # bound to the caller. |
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| 92 | # |
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| 93 | # With one argument, this returns the callback associated with the |
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| 94 | # specified !event for the given caller. |
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| 95 | # |
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| 96 | # Otherwise, it sets the callback for one or more events. If the |
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| 97 | # -now flag is specified, then the callback is invoked immediately |
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| 98 | # to send data back to this caller. This comes in handy when the |
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| 99 | # caller is set up to react to changes. It provides a way of |
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| 100 | # initializing the client, as if an event had just occurred. |
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| 101 | # ---------------------------------------------------------------------- |
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| 102 | itcl::body Rappture::DispatchObj::dispatch {caller args} { |
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| 103 | if {[llength $args] == 0} { |
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[1929] | 104 | # no args? then return a list of events for this caller |
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| 105 | foreach key [array names _dispatch $caller-*] { |
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| 106 | set name [lindex [split $key -] 1] |
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| 107 | set events($name) 1 |
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| 108 | } |
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| 109 | return [array names events] |
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[1] | 110 | } elseif {[llength $args] == 1} { |
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[1929] | 111 | set name [lindex $args 0] |
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| 112 | if {[info exists _dispatch($caller-$name)]} { |
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| 113 | return $_dispatch($caller-$name) |
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| 114 | } |
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| 115 | return "" |
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[1] | 116 | } |
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| 117 | |
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| 118 | # set a callback for one or more events |
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| 119 | set now 0 |
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| 120 | set events "" |
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| 121 | set callback [lindex $args end] |
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| 122 | foreach str [lrange $args 0 end-1] { |
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[1929] | 123 | if {$str == "-now"} { |
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| 124 | set now 1 |
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| 125 | } elseif {[info exists _event2clients($str)]} { |
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| 126 | lappend events $str |
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| 127 | } else { |
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| 128 | if {[string index $str 0] == "-"} { |
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| 129 | error "bad option \"$str\": should be -now" |
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| 130 | } else { |
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| 131 | error "bad event \"$str\": should be [join [lsort [array names _event2clients]] {, }]" |
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| 132 | } |
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| 133 | } |
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[1] | 134 | } |
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| 135 | |
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| 136 | # |
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| 137 | # If the callback is "", then remove the callback for this |
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| 138 | # caller. Otherwise, set the callback for this caller. |
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| 139 | # |
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| 140 | foreach name $events { |
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[1929] | 141 | cancel $name |
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[1] | 142 | |
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[1929] | 143 | if {"" == $callback} { |
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| 144 | catch {unset _dispatch($caller-$name)} |
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| 145 | if {"" == [array names _dispatch $caller-*]} { |
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| 146 | set i [lsearch $_event2clients($name) $caller] |
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| 147 | if {$i >= 0} { |
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| 148 | set _event2clients($name) [lreplace $_event2clients($name) $i $i] |
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| 149 | } |
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| 150 | } |
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| 151 | } else { |
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| 152 | set _dispatch($caller-$name) $callback |
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| 153 | set i [lsearch $_event2clients($name) $caller] |
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| 154 | if {$i < 0} { lappend _event2clients($name) $caller } |
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[1] | 155 | |
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[1929] | 156 | if {$now} { |
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| 157 | _send $name $caller |
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| 158 | } |
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| 159 | } |
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[1] | 160 | } |
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| 161 | } |
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| 162 | |
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| 163 | # ---------------------------------------------------------------------- |
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| 164 | # USAGE: event ?-now? ?-later? ?-idle? ?-after time? !event ?args...? |
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| 165 | # |
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| 166 | # Clients use this to dispatch an event to any callers who have |
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| 167 | # registered their interest. |
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| 168 | # ---------------------------------------------------------------------- |
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| 169 | itcl::body Rappture::DispatchObj::event {args} { |
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| 170 | set when "-now" |
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| 171 | set first [lindex $args 0] |
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| 172 | if {[string index $first 0] == "-"} { |
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[1929] | 173 | switch -- $first { |
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| 174 | -now { |
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| 175 | set when "-now" |
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| 176 | set args [lrange $args 1 end] |
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| 177 | } |
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| 178 | -later { |
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| 179 | set when 1 |
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| 180 | set args [lrange $args 1 end] |
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| 181 | } |
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| 182 | -idle { |
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| 183 | set when "-idle" |
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| 184 | set args [lrange $args 1 end] |
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| 185 | } |
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| 186 | -after { |
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| 187 | set when [lindex $args 1] |
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| 188 | if {![string is int $when]} { |
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| 189 | error "bad value \"$when\": should be int (time in ms)" |
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| 190 | } |
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| 191 | set args [lrange $args 2 end] |
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| 192 | } |
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| 193 | default { |
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| 194 | error "bad option \"$first\": should be -now, -later, -idle, or -after" |
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| 195 | } |
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| 196 | } |
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[1] | 197 | } |
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| 198 | |
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| 199 | if {[llength $args] < 1} { |
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[1929] | 200 | error "wrong # args: should be \"event ?switches? !event ?args...?\"" |
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[1] | 201 | } |
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| 202 | set event [lindex $args 0] |
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| 203 | set args [lrange $args 1 end] |
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| 204 | if {![info exists _event2clients($event)]} { |
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[1929] | 205 | error "bad event \"$event\": should be [join [lsort [array names _event2clients]] {, }]" |
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[1] | 206 | } |
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| 207 | |
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| 208 | switch -- $when { |
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[1929] | 209 | -now { |
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| 210 | _send $event all $args |
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| 211 | } |
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| 212 | -idle { |
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| 213 | set _extraargs($event) $args |
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| 214 | after cancel [itcl::code $this _send $event all @extra] |
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| 215 | after idle [itcl::code $this _send $event all @extra] |
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| 216 | } |
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| 217 | default { |
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| 218 | set _extraargs($event) $args |
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| 219 | after cancel [itcl::code $this _send $event all @extra] |
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| 220 | after $when [itcl::code $this _send $event all @extra] |
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| 221 | } |
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[1] | 222 | } |
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| 223 | } |
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| 224 | |
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| 225 | # ---------------------------------------------------------------------- |
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| 226 | # USAGE: cancel ?!event ...? |
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[2744] | 227 | # cancel all |
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[1] | 228 | # |
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| 229 | # Used to cancel any event notifications pending for the specified |
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| 230 | # list of events. Notifications may be pending if a particular |
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| 231 | # event was raised with the -idle or -after flags. |
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| 232 | # ---------------------------------------------------------------------- |
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| 233 | itcl::body Rappture::DispatchObj::cancel {args} { |
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[1539] | 234 | if { $args == "all" } { |
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[1929] | 235 | foreach event [array names _event2clients] { |
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| 236 | after cancel [itcl::code $this _send $event all @extra] |
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| 237 | } |
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| 238 | return |
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[1539] | 239 | } |
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[1] | 240 | foreach event $args { |
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[1929] | 241 | if {![info exists _event2clients($event)]} { |
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| 242 | error "bad event \"$event\": should be [join [lsort [array names _event2clients]] {, }]" |
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| 243 | } |
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| 244 | after cancel [itcl::code $this _send $event all @extra] |
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[1] | 245 | } |
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| 246 | } |
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| 247 | |
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| 248 | # ---------------------------------------------------------------------- |
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| 249 | # USAGE: ispending !event |
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| 250 | # |
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| 251 | # Returns 1 if the specified !event is pending, and 0 otherwise. |
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| 252 | # Notifications may be pending if a particular event was raised |
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| 253 | # with the -idle or -after flags. |
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| 254 | # ---------------------------------------------------------------------- |
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| 255 | itcl::body Rappture::DispatchObj::ispending {event} { |
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| 256 | set cmd [itcl::code $this _send $event all @extra] |
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| 257 | foreach id [after info] { |
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[1929] | 258 | set cmd2 [lindex [after info $id] 0] |
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| 259 | if {[string equal $cmd $cmd2]} { |
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| 260 | return 1 |
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| 261 | } |
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[1] | 262 | } |
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| 263 | return 0 |
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| 264 | } |
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| 265 | |
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| 266 | # ---------------------------------------------------------------------- |
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| 267 | # USAGE: _send !event caller ?arglist? |
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| 268 | # |
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| 269 | # Used internally to send an event to one or all callers. The event |
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| 270 | # is sent by first invoking a callback to generate any data associated |
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| 271 | # with the event. This data, along with any extra args passed in, |
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| 272 | # are added to the callback for the caller. |
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| 273 | # ---------------------------------------------------------------------- |
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| 274 | itcl::body Rappture::DispatchObj::_send {event caller {arglist ""}} { |
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| 275 | if {$caller == "all"} { |
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[1929] | 276 | set caller $_event2clients($event) |
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[1] | 277 | } |
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| 278 | if {$arglist == "@extra" && [info exists _extraargs($event)]} { |
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[1929] | 279 | set arglist $_extraargs($event) |
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[1] | 280 | } |
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| 281 | |
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| 282 | # if there are any clients for this event, get the arguments ready |
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| 283 | set any 0 |
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| 284 | foreach cname $caller { |
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[1929] | 285 | if {[info exists _dispatch($cname-$event)]} { |
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| 286 | set any 1 |
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| 287 | break |
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| 288 | } |
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[1] | 289 | } |
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| 290 | |
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| 291 | set dargs "" |
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| 292 | if {$any && [string length $_event2datacb($event)] > 0} { |
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[1929] | 293 | # get the args from the data callback |
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| 294 | set status [catch { |
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| 295 | uplevel #0 $_event2datacb($event) $event |
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| 296 | } dargs] |
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[1] | 297 | |
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[1929] | 298 | if {$status != 0} { |
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| 299 | # anything go wrong? then throw a background error |
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| 300 | bgerror "$dargs\n(while dispatching $event)" |
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| 301 | set dargs "" |
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| 302 | } |
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[1] | 303 | } |
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| 304 | # add any arguments added from command line |
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| 305 | eval lappend dargs $arglist |
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| 306 | |
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| 307 | foreach cname $caller { |
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[1929] | 308 | if {[info exists _dispatch($cname-$event)]} { |
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| 309 | set status [catch { |
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| 310 | uplevel #0 $_dispatch($cname-$event) event $event $dargs |
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| 311 | } result] |
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[1] | 312 | |
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[1929] | 313 | if {$status != 0} { |
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| 314 | # anything go wrong? then throw a background error |
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| 315 | bgerror "$result\n(while dispatching $event to $cname)" |
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| 316 | } |
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| 317 | } |
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[1] | 318 | } |
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| 319 | } |
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| 320 | |
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| 321 | # ---------------------------------------------------------------------- |
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| 322 | # BASE CLASS: Dispatcher |
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| 323 | # ---------------------------------------------------------------------- |
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| 324 | itcl::class Rappture::Dispatcher { |
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| 325 | constructor {args} { |
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[1929] | 326 | Rappture::dispatcher _dispatcher |
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| 327 | $_dispatcher register !destroy |
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[1] | 328 | |
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[1929] | 329 | eval configure $args |
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[1] | 330 | } |
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| 331 | |
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| 332 | destructor { |
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[1929] | 333 | event !destroy |
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[1] | 334 | } |
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| 335 | |
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| 336 | public method dispatch {args} { |
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[1929] | 337 | eval $_dispatcher dispatch $args |
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[1] | 338 | } |
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| 339 | |
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| 340 | protected method register {args} { |
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[1929] | 341 | eval $_dispatcher register $args |
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[1] | 342 | } |
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| 343 | protected method event {args} { |
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[1929] | 344 | eval $_dispatcher event $args object $this |
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[1] | 345 | } |
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| 346 | |
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| 347 | private variable _dispatcher "" ;# dispatcher for events |
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| 348 | } |
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