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

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#if SWIFT_PACKAGE
  import CgRPC
#endif

/// A general-purpose Mutex used to synchronize gRPC operations
/// but it can be used anywhere
public class Mutex {

  /// Pointer to underlying C representation
  private var underlyingMutex: UnsafeMutableRawPointer

  /// Initializes a Mutex
  public init() {
    underlyingMutex = cgrpc_mutex_create();
  }

  deinit {
    cgrpc_mutex_destroy(underlyingMutex);
  }

  /// Locks a Mutex
  ///
  /// Waits until no thread has a lock on the Mutex, 
  /// causes the calling thread to own an exclusive lock on the Mutex,
  /// then returns. 
  ///
  /// May block indefinitely or crash if the calling thread has a lock on the Mutex.
  public func lock() {
    cgrpc_mutex_lock(underlyingMutex);
  }

  /// Unlocks a Mutex
  ///
  /// Releases an exclusive lock on the Mutex held by the calling thread.
  public func unlock() {
    cgrpc_mutex_unlock(underlyingMutex);
  }

  /// Runs a block within a locked mutex
  ///
  /// Parameter block: the code to run while the mutex is locked
  public func synchronize(block:() -> Void) {
    lock()
    block()
    unlock()
  }
}