grpc-swift/Packages/gRPC/Sources/CompletionQueue.swift

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#if SWIFT_PACKAGE
  import CgRPC
#endif

/// A gRPC Completion Queue
public class CompletionQueue {

  var name : String!

  /// Pointer to underlying C representation
  var cq : UnsafeMutableRawPointer!

  /// Operation groups that are awaiting completion, keyed by tag
  public var operationGroups : [Int64 : OperationGroup] = [:]

  /// Initializes a CompletionQueue
  ///
  /// - Parameter cq: the underlying C representation
  init(cq: UnsafeMutableRawPointer) {
    self.cq = cq // NOT OWNED, so we don't dealloc it
  }

  /// Waits for an event to complete
  ///
  /// - Parameter timeout: a timeout value in seconds
  /// - Returns: a grpc_completion_type code indicating the result of waiting
  public func waitForCompletion(timeout: Double) -> grpc_event {
    return cgrpc_completion_queue_get_next_event(cq, timeout);
  }

  /// Run a completion queue
  public func run(completion:@escaping () -> Void) {
    DispatchQueue.global().async {
      var running = true
      while (running) {
        let event = cgrpc_completion_queue_get_next_event(self.cq, -1.0)
        switch (event.type) {
        case GRPC_OP_COMPLETE:
          let tag = cgrpc_event_tag(event)
          if let operations = self.operationGroups[tag] {
            operations.completion(event)
            self.operationGroups[tag] = nil
          }
          break
        case GRPC_QUEUE_SHUTDOWN:
          running = false
          break
        case GRPC_QUEUE_TIMEOUT:
          break
        default:
          break
        }
      }
      DispatchQueue.main.async {
        print("exiting completion queue loop " + self.name)
        completion()
      }
    }
  }
}