content: /*
   * Copyright The OpenTelemetry Authors
   * SPDX-License-Identifier: Apache-2.0
   */
  
  package io.opentelemetry.javaagent.instrumentation.executors;
  
  import static net.bytebuddy.matcher.ElementMatchers.named;
  import static net.bytebuddy.matcher.ElementMatchers.takesArguments;
  
  import io.opentelemetry.javaagent.bootstrap.executors.ExecutorAdviceHelper;
  import io.opentelemetry.javaagent.extension.instrumentation.TypeInstrumentation;
  import io.opentelemetry.javaagent.extension.instrumentation.TypeTransformer;
  import net.bytebuddy.asm.Advice;
  import net.bytebuddy.description.type.TypeDescription;
  import net.bytebuddy.matcher.ElementMatcher;
  
  public class VirtualThreadInstrumentation implements TypeInstrumentation {
  
    @Override
    public ElementMatcher<TypeDescription> typeMatcher() {
      return named("java.lang.VirtualThread");
    }
  
    @Override
    public void transform(TypeTransformer transformer) {
      // Disable context propagation when virtual thread is switched to the carrier thread. We should
      // not propagate context on the carrier thread. Also, context propagation code can cause the
      // carrier thread to park when it normally does not park, which may be unexpected for the jvm.
      // https://github.com/open-telemetry/opentelemetry-java-instrumentation/issues/10747
      transformer.applyAdviceToMethod(
          named("switchToCarrierThread").and(takesArguments(0)),
          this.getClass().getName() + "$SwitchToCarrierAdvice");
      transformer.applyAdviceToMethod(
          // takes an extra argument in jdk 21 ea versions
          named("switchToVirtualThread").and(takesArguments(1).or(takesArguments(2))),
          this.getClass().getName() + "$SwitchToVirtualAdvice");
    }
  
    @SuppressWarnings("unused")
    public static class SwitchToCarrierAdvice {
  
      @Advice.OnMethodExit(suppress = Throwable.class)
      public static void exit() {
        ExecutorAdviceHelper.disablePropagation();
      }
    }
  
    @SuppressWarnings("unused")
    public static class SwitchToVirtualAdvice {
  
      @Advice.OnMethodEnter(suppress = Throwable.class)
      public static void enter() {
        ExecutorAdviceHelper.enablePropagation();
      }
    }
  }
  