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module Timer
# timer event, something to do and when/how often to do it
class Action
# when this action is due next (updated by tick())
attr_reader :in
# is this action blocked? if so it won't be run
attr_accessor :blocked
# period:: how often (seconds) to run the action
# data:: optional data to pass to the proc
# once:: optional, if true, this action will be run once then removed
# func:: associate a block to be called to perform the action
#
# create a new action
def initialize(period, data=nil, once=false, &func)
@blocked = false
@period = period
@in = period
@func = func
@data = data
@once = once
@last_tick = Time.new
end
def tick
diff = Time.new - @last_tick
@in -= diff
@last_tick = Time.new
end
def inspect
"#<#{self.class}:#{@period}s:#{@once ? 'once' : 'repeat'}>"
end
def due?
@in <= 0
end
# run the action by calling its proc
def run
@in += @period
# really short duration timers can overrun and leave @in negative,
# for these we set @in to @period
@in = @period if @in <= 0
begin
if(@data)
@func.call(@data)
else
@func.call
end
rescue => e
error "Timer action #{self.inspect} with function #{@func.inspect} failed with error #{e.inspect}"
error e.backtrace.join("\n")
# TODO maybe we want to block this Action?
end
return @once
end
# reschedule the Action to change its period
def reschedule(new_period)
@period = new_period
@in = new_period
end
end
# timer handler, manage multiple Action objects, calling them when required.
# The timer must be ticked by whatever controls it, i.e. regular calls to
# tick() at whatever granularity suits your application's needs.
#
# Alternatively you can call run(), and the timer will spawn a thread and
# tick itself, intelligently shutting down the thread if there are no
# pending actions.
class Timer
def initialize(granularity = 0.1)
@granularity = granularity
@timers = Hash.new
@handle = 0
@lasttime = 0
@should_be_running = false
@thread = false
@next_action_time = 0
end
# period:: how often (seconds) to run the action
# data:: optional data to pass to the action's proc
# func:: associate a block with add() to perform the action
#
# add an action to the timer
def add(period, data=nil, &func)
debug "adding timer, period #{period}"
@handle += 1
@timers[@handle] = Action.new(period, data, &func)
start_on_add
return @handle
end
# period:: how long (seconds) until the action is run
# data:: optional data to pass to the action's proc
# func:: associate a block with add() to perform the action
#
# add an action to the timer which will be run just once, after +period+
def add_once(period, data=nil, &func)
debug "adding one-off timer, period #{period}"
@handle += 1
@timers[@handle] = Action.new(period, data, true, &func)
start_on_add
return @handle
end
# remove action with handle +handle+ from the timer
def remove(handle)
@timers.delete(handle)
end
# block action with handle +handle+
def block(handle)
@timers[handle].blocked = true
end
# unblock action with handle +handle+
def unblock(handle)
@timers[handle].blocked = false
end
# reschedule action with handle +handle+ to change its period
def reschedule(handle, period)
@timers[handle].reschedule(period)
end
# you can call this when you know you're idle, or you can split off a
# thread and call the run() method to do it for you.
def tick
if(@lasttime == 0)
# don't do anything on the first tick
@lasttime = Time.now
return
end
@next_action_time = 0
diff = (Time.now - @lasttime).to_f
@lasttime = Time.now
@timers.each { |key,timer|
timer.tick
next if timer.blocked
if(timer.due?)
if(timer.run)
# run once
@timers.delete(key)
end
end
if @next_action_time == 0 || timer.in < @next_action_time
@next_action_time = timer.in
end
}
#debug "ticked. now #{@timers.length} timers remain"
#debug "next timer due at #{@next_action_time}"
end
# for backwards compat - this is a bit primitive
def run(granularity=0.1)
while(true)
sleep(granularity)
tick
end
end
def running?
@thread && @thread.alive?
end
# return the number of seconds until the next action is due, or 0 if
# none are outstanding - will only be accurate immediately after a
# tick()
def next_action_time
@next_action_time
end
# start the timer, it spawns a thread to tick the timer, intelligently
# shutting down if no events remain and starting again when needed.
def start
return if running?
@should_be_running = true
start_thread unless @timers.empty?
end
# stop the timer from ticking
def stop
@should_be_running = false
stop_thread
end
private
def start_on_add
if running?
stop_thread
start_thread
elsif @should_be_running
start_thread
end
end
def stop_thread
return unless running?
@thread.kill
end
def start_thread
return if running?
@thread = Thread.new do
while(true)
tick
exit if @timers.empty?
sleep(@next_action_time)
end
end
end
end
end
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