Class: ZMQMachine::Timers
- Inherits:
-
Object
- Object
- ZMQMachine::Timers
- Defined in:
- lib/zm/timers.rb
Overview
Manages the addition and cancellation of all timers. Each #Reactor maintains its own set of timers; the timer belongs to the reactor context.
This should never be instantiated directly by user code. A timer must be known to the #Reactor in which it is running, so use the #Reactor#oneshot_timer and #Reactor#periodical_timer convenience methods. It ensures that new timers are installed in the correct #Reactor.
Class Method Summary collapse
-
.now ⇒ Object
Returns the current time using the following algo:.
-
.now_converted ⇒ Object
Convert Timers.now to a number usable by the Time class.
Instance Method Summary collapse
-
#add_oneshot(delay, timer_proc = nil, &blk) ⇒ Object
Adds a non-periodical, one-shot timer in order of first-to-fire to last-to-fire.
-
#add_periodical(delay, timer_proc = nil, &blk) ⇒ Object
Adds a periodical timer in order of first-to-fire to last-to-fire.
-
#cancel(timer) ⇒ Object
Cancel the
timer
. -
#fire_expired ⇒ Object
A convenience method that loops through all known timers and fires all of the expired timers.
-
#initialize ⇒ Timers
constructor
A new instance of Timers.
- #list ⇒ Object
-
#reschedule ⇒ Object
Runs through all timers and asks each one to reschedule itself from Timers.now + whatever delay was originally recorded.
Constructor Details
#initialize ⇒ Timers
Returns a new instance of Timers.
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# File 'lib/zm/timers.rb', line 50 def initialize @timers = [] end |
Class Method Details
.now ⇒ Object
Returns the current time using the following algo:
(Time.now.to_f * 1000).to_i
Added as a class method so that it can be overridden by a user who wants to provide their own time source. For example, a user could use a third-party gem that provides a better performing time source.
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# File 'lib/zm/timers.rb', line 180 def self.now (Time.now.to_f * 1000).to_i end |
.now_converted ⇒ Object
Convert Timers.now to a number usable by the Time class.
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# File 'lib/zm/timers.rb', line 186 def self.now_converted now / 1000.0 end |
Instance Method Details
#add_oneshot(delay, timer_proc = nil, &blk) ⇒ Object
Adds a non-periodical, one-shot timer in order of first-to-fire to last-to-fire.
Returns nil unless a timer_proc
or blk
are provided. There is no point to an empty timer that does nothing when fired.
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# File 'lib/zm/timers.rb', line 65 def add_oneshot delay, timer_proc = nil, &blk blk ||= timer_proc return nil unless blk timer = Timer.new self, delay, false, blk add timer timer end |
#add_periodical(delay, timer_proc = nil, &blk) ⇒ Object
Adds a periodical timer in order of first-to-fire to last-to-fire.
Returns nil unless a timer_proc
or blk
are provided. There is no point to an empty timer that does nothing when fired.
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# File 'lib/zm/timers.rb', line 81 def add_periodical delay, timer_proc = nil, &blk blk ||= timer_proc return nil unless blk timer = Timer.new self, delay, true, blk add timer timer end |
#cancel(timer) ⇒ Object
Cancel the timer
.
Returns true
when cancellation succeeds. Returns false
when it fails to find the given timer
.
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# File 'lib/zm/timers.rb', line 96 def cancel timer i = index timer # when #index doesn't find a match, it returns an index 1 past # the end, so check for that if i < @timers.size && timer == @timers.at(i) @timers.delete_at(i) ? true : false else # slow branch; necessary since the #index operation works # solely from the timer.fire_time attribute. There # could be multiple timers scheduled to fire at the # same time so the equivalence test above could fail # on the first index returned, so fallback to this # slower method size = @timers.size @timers.delete_if { |t| t == timer } # true when the array has shrunk, false otherwise @timers.size != size end end |
#fire_expired ⇒ Object
A convenience method that loops through all known timers and fires all of the expired timers.
– Internally the list is sorted whenever a timer is added or deleted. It stops processing this list when the next timer is not yet expired; it knows all subsequent timers are not expired too.
timers should be sorted by expiration time NOTE: was using #delete_if here, but it does not delete any items when the break executes before iterating through the entire set; that’s unacceptable so I save each timer for deletion and do that in a separate loop
Additionally, some timers may execute code paths that cancel other timers. If those timers are deleted while we are still iterating over them, the behavior is undefined (each runtime can handle it differently). To avoid that issue, we determine if they are expired and save them off for final processing outside of the loop. Any firing timer that deletes another timer will be safe.
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# File 'lib/zm/timers.rb', line 140 def fire_expired # all time is expected as milliseconds now = Timers.now runnables, periodicals, expired_count = [], [], 0 # defer firing the timer until after this loop so we can clean it up first @timers.each do |timer| break unless timer.expired?(now) runnables << timer periodicals << timer if timer.periodical? expired_count += 1 end remove expired_count runnables.each { |timer| timer.fire } renew periodicals end |
#list ⇒ Object
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# File 'lib/zm/timers.rb', line 54 def list @timers end |
#reschedule ⇒ Object
Runs through all timers and asks each one to reschedule itself from Timers.now + whatever delay was originally recorded.
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# File 'lib/zm/timers.rb', line 161 def reschedule timers = @timers.dup @timers.clear timers.each do |timer| timer.reschedule add timer end end |