Improve bytebuddy class enhance for retransform classes

CHANGES.md

@@ -12,6 +12,7 @@ Release Notes.
 * Fix the conflict between the logging kernel and the JDK threadpool plugin.
 * Fix the thread safety bug of finishing operation for the span named "SpringCloudGateway/sendRequest"
 * Fix NPE in guava-eventbus-plugin.
+* Support re-transform/hot-swap classes with other java agents, and remove the obsolete cache enhanced class feature. 
 
 #### Documentation
 

apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/conf/Config.java

@@ -25,7 +25,6 @@
 import org.apache.skywalking.apm.agent.core.logging.core.LogOutput;
 import org.apache.skywalking.apm.agent.core.logging.core.ResolverType;
 import org.apache.skywalking.apm.agent.core.logging.core.WriterFactory;
-import org.apache.skywalking.apm.agent.core.plugin.bytebuddy.ClassCacheMode;
 import org.apache.skywalking.apm.util.Length;
 
 /**
@@ -110,19 +109,6 @@ public static class Agent {
          */
         public static boolean IS_OPEN_DEBUGGING_CLASS = false;
 
-        /**
-         * If true, SkyWalking agent will cache all instrumented classes to memory or disk files (decided by class cache
-         * mode), allow other javaagent to enhance those classes that enhanced by SkyWalking agent.
-         */
-        public static boolean IS_CACHE_ENHANCED_CLASS = false;
-
-        /**
-         * The instrumented classes cache mode: MEMORY or FILE MEMORY: cache class bytes to memory, if instrumented
-         * classes is too many or too large, it may take up more memory FILE: cache class bytes in `/class-cache`
-         * folder, automatically clean up cached class files when the application exits
-         */
-        public static ClassCacheMode CLASS_CACHE_MODE = ClassCacheMode.MEMORY;
-
         /**
          * The identifier of the instance
          */

apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/conf/Constants.java

@@ -32,4 +32,10 @@ public class Constants {
     public static String EVENT_LAYER_NAME = "GENERAL";
 
     public static int NULL_VALUE = 0;
+
+    /**
+     * The name trait for auxiliary type names, field names and method names which generated by ByteBuddy.
+     */
+    public static final String NAME_TRAIT = "sw$";
+
 }

apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/plugin/bytebuddy/AnnotationTypeNameMatch.java

@@ -55,6 +55,17 @@ public boolean matches(T target) {
         return target.getAnnotationType().asErasure().getName().equals(annotationTypeName);
     }
 
+    /**
+     * To ensure that the hashCode for recreating the XxxInterceptPoint instance is the same as the previous instance,
+     * each ElementMatcher implementation class needs to implement toString() method.
+     */
+    @Override
+    public String toString() {
+        return "AnnotationTypeNameMatch{" +
+                "annotationTypeName='" + annotationTypeName + '\'' +
+                '}';
+    }
+
     /**
      * The static method to create {@link AnnotationTypeNameMatch} This is a delegate method to follow byte-buddy {@link
      * ElementMatcher}'s code style.

apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/plugin/bytebuddy/ArgumentTypeNameMatch.java

@@ -68,6 +68,18 @@ public boolean matches(MethodDescription target) {
         return false;
     }
 
+    /**
+     * To ensure that the hashCode for recreating the XxxInterceptPoint instance is the same as the previous instance,
+     * each ElementMatcher implementation class needs to implement toString() method.
+     */
+    @Override
+    public String toString() {
+        return "ArgumentTypeNameMatch{" +
+                "index=" + index +
+                ", argumentTypeName='" + argumentTypeName + '\'' +
+                '}';
+    }
+
     /**
      * The static method to create {@link ArgumentTypeNameMatch} This is a delegate method to follow byte-buddy {@link
      * ElementMatcher}'s code style.

apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/plugin/bytebuddy/ReturnTypeNameMatch.java

@@ -53,6 +53,17 @@ public boolean matches(MethodDescription target) {
         return target.getReturnType().asErasure().getName().equals(returnTypeName);
     }
 
+    /**
+     * To ensure that the hashCode for recreating the XxxInterceptPoint instance is the same as the previous instance,
+     * each ElementMatcher implementation class needs to implement toString() method.
+     */
+    @Override
+    public String toString() {
+        return "ReturnTypeNameMatch{" +
+                "returnTypeName='" + returnTypeName + '\'' +
+                '}';
+    }
+
     /**
      * The static method to create {@link ReturnTypeNameMatch} This is a delegate method to follow byte-buddy {@link
      * ElementMatcher}'s code style.

apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/plugin/interceptor/ConstructorInterceptPoint.java

@@ -21,6 +21,8 @@
 import net.bytebuddy.description.method.MethodDescription;
 import net.bytebuddy.matcher.ElementMatcher;
 
+import java.util.Objects;
+
 /**
  * One of the three "Intercept Point". "Intercept Point" is a definition about where and how intercept happens. In this
  * "Intercept Point", the definition targets class's constructors, and the interceptor.
@@ -41,4 +43,13 @@ public interface ConstructorInterceptPoint {
      * org.apache.skywalking.apm.agent.core.plugin.interceptor.enhance.InstanceConstructorInterceptor}
      */
     String getConstructorInterceptor();
+
+    /**
+     * To ensure that the hashCode for recreating the XxxInterceptPoint instance is the same as the previous instance,
+     * each ElementMatcher implementation class needs to implement toString() method.
+     * @return hashCode of this intercept point
+     */
+    default int computeHashCode() {
+        return Objects.hash(this.getClass().getName(), this.getConstructorMatcher().toString(), this.getConstructorInterceptor());
+    }
 }

apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/plugin/interceptor/InstanceMethodsInterceptPoint.java

@@ -21,6 +21,8 @@
 import net.bytebuddy.description.method.MethodDescription;
 import net.bytebuddy.matcher.ElementMatcher;
 
+import java.util.Objects;
+
 /**
  * One of the three "Intercept Point". "Intercept Point" is a definition about where and how intercept happens. In this
  * "Intercept Point", the definition targets class's instance methods, and the interceptor.
@@ -42,4 +44,13 @@ public interface InstanceMethodsInterceptPoint {
     String getMethodsInterceptor();
 
     boolean isOverrideArgs();
+
+    /**
+     * To ensure that the hashCode for recreating the XxxInterceptPoint instance is the same as the previous instance,
+     * each ElementMatcher implementation class needs to implement toString() method.
+     * @return hashCode of this intercept point
+     */
+    default int computeHashCode() {
+        return Objects.hash(this.getClass().getName(), this.getMethodsMatcher().toString(), this.getMethodsInterceptor(), this.isOverrideArgs());
+    }
 }

apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/plugin/interceptor/StaticMethodsInterceptPoint.java

@@ -21,6 +21,8 @@
 import net.bytebuddy.description.method.MethodDescription;
 import net.bytebuddy.matcher.ElementMatcher;
 
+import java.util.Objects;
+
 /**
  * One of the three "Intercept Point". "Intercept Point" is a definition about where and how intercept happens. In this
  * "Intercept Point", the definition targets class's static methods, and the interceptor.
@@ -42,4 +44,13 @@ public interface StaticMethodsInterceptPoint {
     String getMethodsInterceptor();
 
     boolean isOverrideArgs();
+
+    /**
+     * To ensure that the hashCode for recreating the XxxInterceptPoint instance is the same as the previous instance,
+     * each ElementMatcher implementation class needs to implement toString() method.
+     * @return hashCode of this intercept point
+     */
+    default int computeHashCode() {
+        return Objects.hash(this.getClass().getName(), this.getMethodsMatcher().toString(), this.getMethodsInterceptor(), this.isOverrideArgs());
+    }
 }