content: /*
   * Copyright The OpenTelemetry Authors
   * SPDX-License-Identifier: Apache-2.0
   */
  
  package io.opentelemetry.javaagent.instrumentation.log4j.appender.v1_2;
  
  import static net.bytebuddy.matcher.ElementMatchers.isMethod;
  import static net.bytebuddy.matcher.ElementMatchers.isProtected;
  import static net.bytebuddy.matcher.ElementMatchers.named;
  import static net.bytebuddy.matcher.ElementMatchers.takesArgument;
  import static net.bytebuddy.matcher.ElementMatchers.takesArguments;
  
  import io.opentelemetry.api.logs.LoggerProvider;
  import io.opentelemetry.javaagent.bootstrap.CallDepth;
  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;
  import org.apache.log4j.Category;
  import org.apache.log4j.Priority;
  
  class Log4jAppenderInstrumentation implements TypeInstrumentation {
  
    @Override
    public ElementMatcher<TypeDescription> typeMatcher() {
      return named("org.apache.log4j.Category");
    }
  
    @Override
    public void transform(TypeTransformer transformer) {
      transformer.applyAdviceToMethod(
          isMethod()
              .and(isProtected())
              .and(named("forcedLog"))
              .and(takesArguments(4))
              .and(takesArgument(0, String.class))
              .and(takesArgument(1, named("org.apache.log4j.Priority")))
              .and(takesArgument(2, Object.class))
              .and(takesArgument(3, Throwable.class)),
          Log4jAppenderInstrumentation.class.getName() + "$ForcedLogAdvice");
    }
  
    @SuppressWarnings("unused")
    public static class ForcedLogAdvice {
  
      @Advice.OnMethodEnter(suppress = Throwable.class)
      public static void methodEnter(
          @Advice.This Category logger,
          @Advice.Argument(1) Priority level,
          @Advice.Argument(2) Object message,
          @Advice.Argument(3) Throwable t,
          @Advice.Local("otelCallDepth") CallDepth callDepth) {
        // need to track call depth across all loggers to avoid double capture when one logging
        // framework delegates to another
        callDepth = CallDepth.forClass(LoggerProvider.class);
        if (callDepth.getAndIncrement() == 0) {
          LogEventMapper.INSTANCE.capture(logger, level, message, t);
        }
      }
  
      @Advice.OnMethodExit(onThrowable = Throwable.class, suppress = Throwable.class)
      public static void methodExit(@Advice.Local("otelCallDepth") CallDepth callDepth) {
        callDepth.decrementAndGet();
      }
    }
  }
  