Hydra_Internals_14.swift

Hydra_Internals_14.swift

public extension Context {

	internal func await<T>(_ promise: Promise<T>) throws -> T {
		guard self.queue != DispatchQueue.main else {
			throw PromiseError.invalidContext
		}
		
		var result: T?
		var error: Error?		
		let semaphore = DispatchSemaphore(value: 0)
		
		promise.then(in: self) { value -> Void in
			result = value
			semaphore.signal()
		}.catch(in: self) { err in
			error = err
			semaphore.signal()
		}
	
		_ = semaphore.wait(timeout: DispatchTime(uptimeNanoseconds: UINT64_MAX))
		
		guard let promiseValue = result else {
			throw error!
		}
		return promiseValue
	}
}