Class: Libuv::Q::DeferredPromise
Overview
A new promise instance is created when a deferred instance is created and can be retrieved by calling deferred.promise
Instance Attribute Summary
Attributes inherited from Promise
Instance Method Summary collapse
-
#initialize(reactor, defer) ⇒ DeferredPromise
constructor
A new instance of DeferredPromise.
- #resolved? ⇒ Boolean
-
#then(callback = nil, errback = nil, progback = nil) ⇒ Promise
regardless of when the promise was or will be resolved / rejected, calls one of the success or error callbacks asynchronously as soon as the result is available.
Methods inherited from Promise
#catch, #finally, #progress, #ruby_catch, #value
Constructor Details
#initialize(reactor, defer) ⇒ DeferredPromise
Returns a new instance of DeferredPromise.
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# File 'lib/libuv/q.rb', line 92 def initialize(reactor, defer) raise ArgumentError unless defer.is_a?(Deferred) super() @reactor = reactor @defer = defer end |
Instance Method Details
#resolved? ⇒ Boolean
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# File 'lib/libuv/q.rb', line 154 def resolved? pending.nil? end |
#then(callback = nil, errback = nil, progback = nil) ⇒ Promise
regardless of when the promise was or will be resolved / rejected, calls one of the success or error callbacks asynchronously as soon as the result is available. The callbacks are called with a single argument, the result or rejection reason.
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# File 'lib/libuv/q.rb', line 107 def then(callback = nil, errback = nil, progback = nil) result = Q.defer(@reactor) callback = Proc.new if block_given? wrappedCallback = proc { |val| begin result.resolve(callback ? callback.call(val) : val) rescue Exception => e result.reject(e) @reactor.log e, 'performing promise resolution callback', @trace end } wrappedErrback = proc { |reason| begin result.resolve(errback ? errback.call(reason) : Q.reject(@reactor, reason)) rescue Exception => e result.reject(e) @reactor.log e, 'performing promise rejection callback', @trace end } wrappedProgback = proc { |*progress| begin result.notify(progback ? progback.call(*progress) : progress) rescue Exception => e @reactor.log e, 'performing promise progress callback', @trace end } # # Schedule as we are touching shared state # Everything else is locally scoped # @reactor.schedule do pending_array = pending if pending_array.nil? reference.then(wrappedCallback, wrappedErrback, wrappedProgback) else pending_array << [wrappedCallback, wrappedErrback, wrappedProgback] end end result.promise end |