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

/*
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#if SWIFT_PACKAGE
  import CgRPC
#endif

/// Singleton class that provides a mutex for synchronizing tag generation
private class OperationGroupTagLock {
  var mutex : Mutex
  private init() {
    mutex = Mutex()
  }
  static let sharedInstance = OperationGroupTagLock()
}

/// A collection of gRPC operations
class OperationGroup {

  /// Used to generate unique tags for OperationGroups
  static var nextTag : Int64 = 1

  /// Automatically-assigned tag that is used with the completion queue.
  var tag : Int64

  /// The call associated with the operation group. Retained while the operations are running.
  var call : Call

  /// An array of operation objects that are passed into the initializer
  var operationsArray : [Operation]?

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

  /// Completion handler that is called when the group completes
  var completion : ((Bool) -> Void)

  /// Initializes a Operations representation
  ///
  /// - Parameter operations: an array of operations
  init(call: Call,
       operations: [Operation],
       completion: @escaping ((Bool) -> Void)) {
    self.call = call
    self.operationsArray = operations
    self.underlyingOperations = cgrpc_operations_create()
    cgrpc_operations_reserve_space_for_operations(self.underlyingOperations, Int32(operations.count))
    for operation in operations {
      cgrpc_operations_add_operation(self.underlyingOperations, operation.underlyingObserver)
    }
    self.completion = completion
    let mutex = OperationGroupTagLock.sharedInstance.mutex
    mutex.lock()
    self.tag = OperationGroup.nextTag
    OperationGroup.nextTag += 1
    mutex.unlock()
  }
}