Shadow JCTools (#476)

Previously, a number of classes from JCTools had been copied and pasted into
the code in order to avoid a JAR-level dependencies on the project.  While the
goal was worthy, the implementation led itself to divergence as the classes in
JCTools were improved and bugs were fixed.  Even the JCTools project
discourages this behavior, instead recommending that you shadow/shade in the
dependency.  From the RSocket perspective, this has the advantage of allowing
the dependency to be specified and kept up to date in the same way that all
the other dependencies of the projects are, and yet still not resulting in a
JAR-level dependency on JCTools.

This change updates the code to use JCTools directly as a dependency and
introduces the shadow plugin, configured to include just the types needed by
the code.

Author: nebhale

build.gradle

@@ -47,6 +47,7 @@ subprojects {
             dependency 'io.aeron:aeron-all:1.4.1'
             dependency 'org.hamcrest:hamcrest-library:1.3'
             dependency 'org.hdrhistogram:HdrHistogram:2.1.10'
+            dependency 'org.jctools:jctools-core:2.1.2'
             dependency 'org.mockito:mockito-core:2.16.0'
             dependency 'org.openjdk.jmh:jmh-core:1.20'
 

rsocket-core/build.gradle

@@ -29,6 +29,7 @@ dependencies {
     api 'io.projectreactor:reactor-core'
 
     implementation 'com.google.code.findbugs:jsr305'
+    implementation 'org.jctools:jctools-core'
     implementation 'org.slf4j:slf4j-api'
 
     testImplementation 'io.projectreactor:reactor-test'
@@ -37,6 +38,26 @@ dependencies {
     testImplementation 'org.mockito:mockito-core'
 }
 
+jar {
+    enabled = false
+    dependsOn(shadowJar { classifier = null })
+}
+
+shadowJar {
+    dependencies {
+        include(dependency('org.jctools:jctools-core'))
+    }
+
+    include '*.jar'
+    include 'io/rsocket/**'
+    include 'org/jctools/maps/ConcurrentAutoTable*.class'
+    include 'org/jctools/maps/NonBlockingHashMapLong*.class'
+    include 'org/jctools/util/RangeUtil*.class'
+    include 'org/jctools/util/UnsafeAccess*.class'
+
+    relocate 'org.jctools', 'io.rsocket.shadowed.org.jctools'
+}
+
 description = "Core functionality for the RSocket library"
 
 apply from: 'jmh.gradle'

rsocket-core/src/main/java/io/rsocket/RSocketClient.java

@@ -21,14 +21,15 @@
 import io.rsocket.exceptions.Exceptions;
 import io.rsocket.internal.LimitableRequestPublisher;
 import io.rsocket.internal.UnboundedProcessor;
-import io.rsocket.util.NonBlockingHashMapLong;
 import java.time.Duration;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.function.Consumer;
 import java.util.function.Function;
 import java.util.function.Supplier;
 import javax.annotation.Nullable;
+
+import org.jctools.maps.NonBlockingHashMapLong;
 import org.reactivestreams.Publisher;
 import org.reactivestreams.Subscriber;
 import reactor.core.Disposable;

rsocket-core/src/main/java/io/rsocket/RSocketServer.java

@@ -25,9 +25,10 @@
 import io.rsocket.exceptions.ApplicationException;
 import io.rsocket.internal.LimitableRequestPublisher;
 import io.rsocket.internal.UnboundedProcessor;
-import io.rsocket.util.NonBlockingHashMapLong;
 import java.util.function.Consumer;
 import java.util.function.Function;
+
+import org.jctools.maps.NonBlockingHashMapLong;
 import org.reactivestreams.Publisher;
 import org.reactivestreams.Subscriber;
 import org.reactivestreams.Subscription;

rsocket-core/src/main/java/io/rsocket/fragmentation/FragmentationDuplexConnection.java

@@ -19,7 +19,7 @@
 import io.rsocket.DuplexConnection;
 import io.rsocket.Frame;
 import io.rsocket.frame.FrameHeaderFlyweight;
-import io.rsocket.util.NonBlockingHashMapLong;
+import org.jctools.maps.NonBlockingHashMapLong;
 import org.reactivestreams.Publisher;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;