content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the
   * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.apache.beam.runners.dataflow.worker;
  
  import static org.apache.beam.sdk.util.Preconditions.checkArgumentNotNull;
  
  import com.google.auto.service.AutoService;
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.Collection;
  import java.util.Map;
  import org.apache.beam.runners.dataflow.util.CloudObject;
  import org.apache.beam.runners.dataflow.worker.util.common.worker.NativeReader;
  import org.apache.beam.runners.dataflow.worker.windmill.Windmill;
  import org.apache.beam.sdk.coders.Coder;
  import org.apache.beam.sdk.coders.KvCoder;
  import org.apache.beam.sdk.options.PipelineOptions;
  import org.apache.beam.sdk.transforms.windowing.BoundedWindow;
  import org.apache.beam.sdk.transforms.windowing.PaneInfo;
  import org.apache.beam.sdk.values.KV;
  import org.apache.beam.sdk.values.WindowedValue;
  import org.apache.beam.sdk.values.WindowedValues;
  import org.apache.beam.sdk.values.WindowedValues.FullWindowedValueCoder;
  import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.collect.ImmutableMap;
  import org.checkerframework.checker.nullness.qual.Nullable;
  import org.joda.time.Instant;
  
  /**
   * A Reader that receives input data from a Windmill server, and returns it as individual elements.
   */
  @SuppressWarnings({
    "rawtypes", // TODO(https://github.com/apache/beam/issues/20447)
    "nullness" // TODO(https://github.com/apache/beam/issues/20497)
  })
  class UngroupedWindmillReader<T> extends NativeReader<WindowedValue<T>> {
    private final Coder<T> valueCoder;
    private final Coder<Collection<? extends BoundedWindow>> windowsCoder;
    private StreamingModeExecutionContext context;
  
    UngroupedWindmillReader(Coder<WindowedValue<T>> coder, StreamingModeExecutionContext context) {
      FullWindowedValueCoder<T> inputCoder = (FullWindowedValueCoder<T>) coder;
      this.valueCoder = inputCoder.getValueCoder();
      this.windowsCoder = inputCoder.getWindowsCoder();
      this.context = context;
    }
  
    /** A {@link ReaderFactory.Registrar} for ungrouped windmill sources. */
    @AutoService(ReaderFactory.Registrar.class)
    public static class Registrar implements ReaderFactory.Registrar {
  
      @Override
      public Map<String, ReaderFactory> factories() {
        Factory factory = new Factory();
        return ImmutableMap.of(
            "UngroupedWindmillReader", factory,
            "org.apache.beam.runners.dataflow.worker.UngroupedWindmillSource", factory,
            "org.apache.beam.runners.dataflow.worker.UngroupedWindmillReader", factory);
      }
    }
  
    static class Factory implements ReaderFactory {
      @Override
      public NativeReader<?> create(
          CloudObject spec,
          @Nullable Coder<?> coder,
          @Nullable PipelineOptions options,
          @Nullable DataflowExecutionContext executionContext,
          DataflowOperationContext operationContext)
          throws Exception {
        coder = checkArgumentNotNull(coder);
        @SuppressWarnings("unchecked")
        Coder<WindowedValue<Object>> typedCoder = (Coder<WindowedValue<Object>>) coder;
        return new UngroupedWindmillReader<>(
            typedCoder, (StreamingModeExecutionContext) executionContext);
      }
    }
  
    @Override
    public NativeReaderIterator<WindowedValue<T>> iterator() throws IOException {
      return new UngroupedWindmillReaderIterator(context.getWorkItem());
    }
  
    class UngroupedWindmillReaderIterator extends WindmillReaderIteratorBase {
      UngroupedWindmillReaderIterator(Windmill.WorkItem work) {
        super(work);
      }
  
      @Override
      public boolean advance() throws IOException {
        if (context.workIsFailed()) {
          return false;
        }
        return super.advance();
      }
  
      @Override
      protected WindowedValue<T> decodeMessage(Windmill.Message message) throws IOException {
        Instant timestampMillis =
            WindmillTimeUtils.windmillToHarnessTimestamp(message.getTimestamp());
        InputStream data = message.getData().newInput();
        InputStream metadata = message.getMetadata().newInput();
        Collection<? extends BoundedWindow> windows =
            WindmillSink.decodeMetadataWindows(windowsCoder, message.getMetadata());
        PaneInfo paneInfo = WindmillSink.decodeMetadataPane(message.getMetadata());
        if (valueCoder instanceof KvCoder) {
          KvCoder<?, ?> kvCoder = (KvCoder<?, ?>) valueCoder;
          InputStream key = context.getSerializedKey().newInput();
          notifyElementRead(key.available() + data.available() + metadata.available());
  
          @SuppressWarnings("unchecked")
          T result =
              (T) KV.of(decode(kvCoder.getKeyCoder(), key), decode(kvCoder.getValueCoder(), data));
          return WindowedValues.of(result, timestampMillis, windows, paneInfo);
        } else {
          notifyElementRead(data.available() + metadata.available());
          return WindowedValues.of(decode(valueCoder, data), timestampMillis, windows, paneInfo);
        }
      }
  
      private <X> X decode(Coder<X> coder, InputStream input) throws IOException {
        return coder.decode(input, Coder.Context.OUTER);
      }
    }
  
    @Override
    public boolean supportsRestart() {
      return true;
    }
  }
  