/**
 * Checks for updates to the server's mutable services and updates the index if any changes are
 * detected. A change is any addition or removal in the set of file descriptors attached to the
 * mutable services or a change in the service names.
 *
 * @return The (potentially updated) index.
 */
private ServerReflectionIndex updateIndexIfNecessary() {
  synchronized (lock) {
    if (serverReflectionIndex == null) {
      serverReflectionIndex =
          new ServerReflectionIndex(server.getImmutableServices(), server.getMutableServices());
      return serverReflectionIndex;
    }

    Set<FileDescriptor> serverFileDescriptors = new HashSet<FileDescriptor>();
    Set<String> serverServiceNames = new HashSet<String>();
    List<ServerServiceDefinition> serverMutableServices = server.getMutableServices();
    for (ServerServiceDefinition mutableService : serverMutableServices) {
      io.grpc.ServiceDescriptor serviceDescriptor = mutableService.getServiceDescriptor();
      if (serviceDescriptor.getSchemaDescriptor() instanceof ProtoFileDescriptorSupplier) {
        String serviceName = serviceDescriptor.getName();
        FileDescriptor fileDescriptor =
            ((ProtoFileDescriptorSupplier) serviceDescriptor.getSchemaDescriptor())
                .getFileDescriptor();
        serverFileDescriptors.add(fileDescriptor);
        serverServiceNames.add(serviceName);
      }
    }

    // Replace the index if the underlying mutable services have changed. Check both the file
    // descriptors and the service names, because one file descriptor can define multiple
    // services.
    FileDescriptorIndex mutableServicesIndex = serverReflectionIndex.getMutableServicesIndex();
    if (!mutableServicesIndex.getServiceFileDescriptors().equals(serverFileDescriptors)
        || !mutableServicesIndex.getServiceNames().equals(serverServiceNames)) {
      serverReflectionIndex =
          new ServerReflectionIndex(server.getImmutableServices(), serverMutableServices);
    }

    return serverReflectionIndex;
  }
}
 

FileDescriptorIndex(List<ServerServiceDefinition> services) {
  Queue<FileDescriptor> fileDescriptorsToProcess = new ArrayDeque<FileDescriptor>();
  Set<String> seenFiles = new HashSet<String>();
  for (ServerServiceDefinition service : services) {
    io.grpc.ServiceDescriptor serviceDescriptor = service.getServiceDescriptor();
    if (serviceDescriptor.getSchemaDescriptor() instanceof ProtoFileDescriptorSupplier) {
      FileDescriptor fileDescriptor =
          ((ProtoFileDescriptorSupplier) serviceDescriptor.getSchemaDescriptor())
              .getFileDescriptor();
      String serviceName = serviceDescriptor.getName();
      checkState(
          !serviceNames.contains(serviceName), "Service already defined: %s", serviceName);
      serviceFileDescriptors.add(fileDescriptor);
      serviceNames.add(serviceName);
      if (!seenFiles.contains(fileDescriptor.getName())) {
        seenFiles.add(fileDescriptor.getName());
        fileDescriptorsToProcess.add(fileDescriptor);
      }
    }
  }

  while (!fileDescriptorsToProcess.isEmpty()) {
    FileDescriptor currentFd = fileDescriptorsToProcess.remove();
    processFileDescriptor(currentFd);
    for (FileDescriptor dependencyFd : currentFd.getDependencies()) {
      if (!seenFiles.contains(dependencyFd.getName())) {
        seenFiles.add(dependencyFd.getName());
        fileDescriptorsToProcess.add(dependencyFd);
      }
    }
  }
}
 

FileDescriptorIndex(List<ServerServiceDefinition> services) {
  Queue<FileDescriptor> fileDescriptorsToProcess = new ArrayDeque<>();
  Set<String> seenFiles = new HashSet<>();
  for (ServerServiceDefinition service : services) {
    io.grpc.ServiceDescriptor serviceDescriptor = service.getServiceDescriptor();
    if (serviceDescriptor.getSchemaDescriptor() instanceof ProtoFileDescriptorSupplier) {
      FileDescriptor fileDescriptor =
          ((ProtoFileDescriptorSupplier) serviceDescriptor.getSchemaDescriptor())
              .getFileDescriptor();
      String serviceName = serviceDescriptor.getName();
      checkState(
          !serviceNames.contains(serviceName), "Service already defined: %s", serviceName);
      serviceFileDescriptors.add(fileDescriptor);
      serviceNames.add(serviceName);
      if (!seenFiles.contains(fileDescriptor.getName())) {
        seenFiles.add(fileDescriptor.getName());
        fileDescriptorsToProcess.add(fileDescriptor);
      }
    }
  }

  while (!fileDescriptorsToProcess.isEmpty()) {
    FileDescriptor currentFd = fileDescriptorsToProcess.remove();
    processFileDescriptor(currentFd);
    for (FileDescriptor dependencyFd : currentFd.getDependencies()) {
      if (!seenFiles.contains(dependencyFd.getName())) {
        seenFiles.add(dependencyFd.getName());
        fileDescriptorsToProcess.add(dependencyFd);
      }
    }
  }
}
 

/**
 * Retrieves the index for services of the server that dispatches the current call. Computes
 * one if not exist. The index is updated if any changes to the server's mutable services are
 * detected. A change is any addition or removal in the set of file descriptors attached to the
 * mutable services or a change in the service names.
 */
private ServerReflectionIndex getRefreshedIndex() {
  synchronized (lock) {
    Server server = InternalServer.SERVER_CONTEXT_KEY.get();
    ServerReflectionIndex index = serverReflectionIndexes.get(server);
    if (index == null) {
      index =
          new ServerReflectionIndex(server.getImmutableServices(), server.getMutableServices());
      serverReflectionIndexes.put(server, index);
      return index;
    }

    Set<FileDescriptor> serverFileDescriptors = new HashSet<>();
    Set<String> serverServiceNames = new HashSet<>();
    List<ServerServiceDefinition> serverMutableServices = server.getMutableServices();
    for (ServerServiceDefinition mutableService : serverMutableServices) {
      io.grpc.ServiceDescriptor serviceDescriptor = mutableService.getServiceDescriptor();
      if (serviceDescriptor.getSchemaDescriptor() instanceof ProtoFileDescriptorSupplier) {
        String serviceName = serviceDescriptor.getName();
        FileDescriptor fileDescriptor =
            ((ProtoFileDescriptorSupplier) serviceDescriptor.getSchemaDescriptor())
                .getFileDescriptor();
        serverFileDescriptors.add(fileDescriptor);
        serverServiceNames.add(serviceName);
      }
    }

    // Replace the index if the underlying mutable services have changed. Check both the file
    // descriptors and the service names, because one file descriptor can define multiple
    // services.
    FileDescriptorIndex mutableServicesIndex = index.getMutableServicesIndex();
    if (!mutableServicesIndex.getServiceFileDescriptors().equals(serverFileDescriptors)
        || !mutableServicesIndex.getServiceNames().equals(serverServiceNames)) {
      index =
          new ServerReflectionIndex(server.getImmutableServices(), serverMutableServices);
      serverReflectionIndexes.put(server, index);
    }

    return index;
  }
}