xds: convert and rename ReferenceCountingSslContextProviderMap to generic ReferenceCountingMap (#7181)

xds/src/main/java/io/grpc/xds/internal/sds/ClientSslContextProviderFactory.java

@@ -21,17 +21,17 @@ import static com.google.common.base.Preconditions.checkNotNull;
 import com.google.common.util.concurrent.ThreadFactoryBuilder;
 import io.grpc.xds.Bootstrapper;
 import io.grpc.xds.EnvoyServerProtoData.UpstreamTlsContext;
-import io.grpc.xds.internal.sds.ReferenceCountingSslContextProviderMap.SslContextProviderFactory;
+import io.grpc.xds.internal.sds.ReferenceCountingMap.ValueFactory;
 import java.io.IOException;
 import java.util.concurrent.Executors;
 
 /** Factory to create client-side SslContextProvider from UpstreamTlsContext. */
 final class ClientSslContextProviderFactory
-    implements SslContextProviderFactory<UpstreamTlsContext> {
+    implements ValueFactory<UpstreamTlsContext, SslContextProvider> {
 
   /** Creates an SslContextProvider from the given UpstreamTlsContext. */
   @Override
-  public SslContextProvider createSslContextProvider(UpstreamTlsContext upstreamTlsContext) {
+  public SslContextProvider create(UpstreamTlsContext upstreamTlsContext) {
     checkNotNull(upstreamTlsContext, "upstreamTlsContext");
     checkNotNull(
         upstreamTlsContext.getCommonTlsContext(),

xds/src/main/java/io/grpc/xds/internal/sds/Closeable.java

@@ -0,0 +1,23 @@
+/*
+ * Copyright 2020 The gRPC Authors
+ *
+ * Licensed 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 io.grpc.xds.internal.sds;
+
+interface Closeable extends java.io.Closeable {
+
+  @Override
+  public void close();
+}

xds/src/main/java/io/grpc/xds/internal/sds/ReferenceCountingMap.java

@@ -26,38 +26,38 @@ import javax.annotation.CheckReturnValue;
 import javax.annotation.concurrent.ThreadSafe;
 
 /**
- * A map for managing {@link SslContextProvider}s as reference-counted shared resources.
+ * A map for managing reference-counted shared resources - typically providers.
  *
- * <p>A key (of generic type K) identifies a {@link SslContextProvider}. The map also depends on a
- * factory {@link SslContextProviderFactory} to create a new instance of {@link SslContextProvider}
- * as needed. {@link SslContextProvider}s are ref-counted and closed by calling {@link
- * SslContextProvider#close()} when ref-count reaches zero.
+ * <p>A key (of generic type K) identifies a provider (of generic type V). The map also depends on a
+ * factory {@link ValueFactory} to create a new instance of V as needed. Values are ref-counted and
+ * closed by calling {@link Closeable#close()} when ref-count reaches zero.
  *
  * @param <K> Key type for the map
+ * @param <V> Value type for the map - it should be a {@link Closeable}
  */
 @ThreadSafe
-final class ReferenceCountingSslContextProviderMap<K> {
+final class ReferenceCountingMap<K, V extends Closeable> {
 
-  private final Map<K, Instance> instances = new HashMap<>();
-  private final SslContextProviderFactory<K> sslContextProviderFactory;
+  private final Map<K, Instance<V>> instances = new HashMap<>();
+  private final ValueFactory<K, V> valueFactory;
 
-  ReferenceCountingSslContextProviderMap(SslContextProviderFactory<K> sslContextProviderFactory) {
-    checkNotNull(sslContextProviderFactory, "sslContextProviderFactory");
-    this.sslContextProviderFactory = sslContextProviderFactory;
+  ReferenceCountingMap(ValueFactory<K, V> valueFactory) {
+    checkNotNull(valueFactory, "valueFactory");
+    this.valueFactory = valueFactory;
   }
 
   /**
-   * Gets an existing instance of {@link SslContextProvider}. If it doesn't exist, creates a new one
-   * using the provided {@link SslContextProviderFactory&lt;K&gt;}
+   * Gets an existing instance of a provider. If it doesn't exist, creates a new one
+   * using the provided {@link ValueFactory &lt;K, V&gt;}
    */
   @CheckReturnValue
-  public SslContextProvider get(K key) {
+  public V get(K key) {
     checkNotNull(key, "key");
     return getInternal(key);
   }
 
   /**
-   * Releases an instance of the given {@link SslContextProvider}.
+   * Releases an instance of the given value.
    *
    * <p>The instance must have been obtained from {@link #get(K)}. Otherwise will throw
    * IllegalArgumentException.
@@ -69,30 +69,30 @@ final class ReferenceCountingSslContextProviderMap<K> {
    * @param value the instance to be released
    * @return a null which the caller can use to clear the reference to that instance.
    */
-  public SslContextProvider release(K key, SslContextProvider value) {
+  public V release(K key, V value) {
     checkNotNull(key, "key");
     checkNotNull(value, "value");
     return releaseInternal(key, value);
   }
 
-  private synchronized SslContextProvider getInternal(K key) {
-    Instance instance = instances.get(key);
+  private synchronized V getInternal(K key) {
+    Instance<V> instance = instances.get(key);
     if (instance == null) {
-      instance = new Instance(sslContextProviderFactory.createSslContextProvider(key));
+      instance = new Instance<>(valueFactory.create(key));
       instances.put(key, instance);
-      return instance.sslContextProvider;
+      return instance.value;
     } else {
       return instance.acquire();
     }
   }
 
-  private synchronized SslContextProvider releaseInternal(K key, SslContextProvider instance) {
-    Instance cached = instances.get(key);
+  private synchronized V releaseInternal(K key, V value) {
+    Instance<V> cached = instances.get(key);
     checkArgument(cached != null, "No cached instance found for %s", key);
-    checkArgument(instance == cached.sslContextProvider, "Releasing the wrong instance");
+    checkArgument(value == cached.value, "Releasing the wrong instance");
     if (cached.release()) {
       try {
-        cached.sslContextProvider.close();
+        cached.value.close();
       } finally {
         instances.remove(key);
       }
@@ -101,19 +101,19 @@ final class ReferenceCountingSslContextProviderMap<K> {
     return null;
   }
 
-  /** A factory to create an SslContextProvider from the given key. */
-  public interface SslContextProviderFactory<K> {
-    SslContextProvider createSslContextProvider(K key);
+  /** A factory to create a value from the given key. */
+  public interface ValueFactory<K, V extends Closeable> {
+    V create(K key);
   }
 
-  private static class Instance {
-    final SslContextProvider sslContextProvider;
+  private static final class Instance<V extends Closeable> {
+    final V value;
     private int refCount;
 
-    /** Increment refCount and acquire a reference to sslContextProvider. */
-    SslContextProvider acquire() {
+    /** Increment refCount and acquire a reference to value. */
+    V acquire() {
       refCount++;
-      return sslContextProvider;
+      return value;
     }
 
     /** Decrement refCount and return true if it has reached 0. */
@@ -122,8 +122,8 @@ final class ReferenceCountingSslContextProviderMap<K> {
       return --refCount == 0;
     }
 
-    Instance(SslContextProvider sslContextProvider) {
-      this.sslContextProvider = sslContextProvider;
+    Instance(V value) {
+      this.value = value;
       this.refCount = 1;
     }
   }

xds/src/main/java/io/grpc/xds/internal/sds/SdsSslContextProvider.java

@@ -203,7 +203,7 @@ abstract class SdsSslContextProvider extends SslContextProvider implements SdsCl
   }
 
   @Override
-  void close() {
+  public void close() {
     if (certSdsClient != null) {
       certSdsClient.cancelSecretWatch(this);
       certSdsClient.shutdown();

xds/src/main/java/io/grpc/xds/internal/sds/ServerSslContextProviderFactory.java

@@ -21,17 +21,17 @@ import static com.google.common.base.Preconditions.checkNotNull;
 import com.google.common.util.concurrent.ThreadFactoryBuilder;
 import io.grpc.xds.Bootstrapper;
 import io.grpc.xds.EnvoyServerProtoData.DownstreamTlsContext;
-import io.grpc.xds.internal.sds.ReferenceCountingSslContextProviderMap.SslContextProviderFactory;
+import io.grpc.xds.internal.sds.ReferenceCountingMap.ValueFactory;
 import java.io.IOException;
 import java.util.concurrent.Executors;
 
 /** Factory to create server-side SslContextProvider from DownstreamTlsContext. */
 final class ServerSslContextProviderFactory
-    implements SslContextProviderFactory<DownstreamTlsContext> {
+    implements ValueFactory<DownstreamTlsContext, SslContextProvider> {
 
   /** Creates a SslContextProvider from the given DownstreamTlsContext. */
   @Override
-  public SslContextProvider createSslContextProvider(
+  public SslContextProvider create(
       DownstreamTlsContext downstreamTlsContext) {
     checkNotNull(downstreamTlsContext, "downstreamTlsContext");
     checkNotNull(

xds/src/main/java/io/grpc/xds/internal/sds/SslContextProvider.java

@@ -41,7 +41,7 @@ import java.util.logging.Logger;
  * stream that is receiving the requested secret(s) or it could represent file-system based
  * secret(s) that are dynamic.
  */
-public abstract class SslContextProvider {
+public abstract class SslContextProvider implements Closeable {
 
   private static final Logger logger = Logger.getLogger(SslContextProvider.class.getName());
 
@@ -93,7 +93,8 @@ public abstract class SslContextProvider {
   }
 
   /** Closes this provider and releases any resources. */
-  void close() {}
+  @Override
+  public abstract void close();
 
   /**
    * Registers a callback on the given executor. The callback will run when SslContext becomes

xds/src/main/java/io/grpc/xds/internal/sds/TlsContextManagerImpl.java

@@ -21,20 +21,20 @@ import static com.google.common.base.Preconditions.checkNotNull;
 import com.google.common.annotations.VisibleForTesting;
 import io.grpc.xds.EnvoyServerProtoData.DownstreamTlsContext;
 import io.grpc.xds.EnvoyServerProtoData.UpstreamTlsContext;
-import io.grpc.xds.internal.sds.ReferenceCountingSslContextProviderMap.SslContextProviderFactory;
+import io.grpc.xds.internal.sds.ReferenceCountingMap.ValueFactory;
 
 /**
  * Class to manage {@link SslContextProvider} objects created from inputs we get from xDS. Used by
  * gRPC-xds to access the SslContext's and is not public API. This manager manages the life-cycle of
  * {@link SslContextProvider} objects as shared resources via ref-counting as described in {@link
- * ReferenceCountingSslContextProviderMap}.
+ * ReferenceCountingMap}.
  */
 public final class TlsContextManagerImpl implements TlsContextManager {
 
   private static TlsContextManagerImpl instance;
 
-  private final ReferenceCountingSslContextProviderMap<UpstreamTlsContext> mapForClients;
-  private final ReferenceCountingSslContextProviderMap<DownstreamTlsContext> mapForServers;
+  private final ReferenceCountingMap<UpstreamTlsContext, SslContextProvider> mapForClients;
+  private final ReferenceCountingMap<DownstreamTlsContext, SslContextProvider> mapForServers;
 
   private TlsContextManagerImpl() {
     this(new ClientSslContextProviderFactory(), new ServerSslContextProviderFactory());
@@ -42,12 +42,12 @@ public final class TlsContextManagerImpl implements TlsContextManager {
 
   @VisibleForTesting
   TlsContextManagerImpl(
-      SslContextProviderFactory<UpstreamTlsContext> clientFactory,
-      SslContextProviderFactory<DownstreamTlsContext> serverFactory) {
+      ValueFactory<UpstreamTlsContext, SslContextProvider> clientFactory,
+      ValueFactory<DownstreamTlsContext, SslContextProvider> serverFactory) {
     checkNotNull(clientFactory, "clientFactory");
     checkNotNull(serverFactory, "serverFactory");
-    mapForClients = new ReferenceCountingSslContextProviderMap<>(clientFactory);
-    mapForServers = new ReferenceCountingSslContextProviderMap<>(serverFactory);
+    mapForClients = new ReferenceCountingMap<>(clientFactory);
+    mapForServers = new ReferenceCountingMap<>(serverFactory);
   }
 
   /** Gets the TlsContextManagerImpl singleton. */

xds/src/test/java/io/grpc/xds/internal/sds/ClientSslContextProviderFactoryTest.java

@@ -42,7 +42,7 @@ public class ClientSslContextProviderFactoryTest {
             CLIENT_KEY_FILE, CLIENT_PEM_FILE, CA_PEM_FILE);
 
     SslContextProvider sslContextProvider =
-        clientSslContextProviderFactory.createSslContextProvider(upstreamTlsContext);
+        clientSslContextProviderFactory.create(upstreamTlsContext);
     assertThat(sslContextProvider).isNotNull();
   }
 
@@ -56,7 +56,7 @@ public class ClientSslContextProviderFactoryTest {
 
     try {
       SslContextProvider unused =
-          clientSslContextProviderFactory.createSslContextProvider(upstreamTlsContext);
+          clientSslContextProviderFactory.create(upstreamTlsContext);
       Assert.fail("no exception thrown");
     } catch (UnsupportedOperationException expected) {
       assertThat(expected)
@@ -78,7 +78,7 @@ public class ClientSslContextProviderFactoryTest {
 
     try {
       SslContextProvider unused =
-          clientSslContextProviderFactory.createSslContextProvider(upstreamTlsContext);
+          clientSslContextProviderFactory.create(upstreamTlsContext);
       Assert.fail("no exception thrown");
     } catch (UnsupportedOperationException expected) {
       assertThat(expected)

xds/src/test/java/io/grpc/xds/internal/sds/ReferenceCountingMapTest.java

@@ -24,7 +24,7 @@ import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
-import io.grpc.xds.internal.sds.ReferenceCountingSslContextProviderMap.SslContextProviderFactory;
+import io.grpc.xds.internal.sds.ReferenceCountingMap.ValueFactory;
 import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
@@ -34,25 +34,26 @@ import org.mockito.Mock;
 import org.mockito.junit.MockitoJUnit;
 import org.mockito.junit.MockitoRule;
 
-/** Unit tests for {@link ReferenceCountingSslContextProviderMap}. */
+/** Unit tests for {@link ReferenceCountingMap}. */
 @RunWith(JUnit4.class)
-public class ReferenceCountingSslContextProviderMapTest {
+public class ReferenceCountingMapTest {
 
   @Rule public final MockitoRule mockitoRule = MockitoJUnit.rule();
 
-  @Mock SslContextProviderFactory<Integer> mockFactory;
+  @Mock
+  ValueFactory<Integer, SslContextProvider> mockFactory;
 
-  ReferenceCountingSslContextProviderMap<Integer> map;
+  ReferenceCountingMap<Integer, SslContextProvider> map;
 
   @Before
   public void setUp() {
-    map = new ReferenceCountingSslContextProviderMap<>(mockFactory);
+    map = new ReferenceCountingMap<>(mockFactory);
   }
 
   @Test
   public void referenceCountingMap_getAndRelease_closeCalled() throws InterruptedException {
     SslContextProvider valueFor3 = getTypedMock();
-    when(mockFactory.createSslContextProvider(3)).thenReturn(valueFor3);
+    when(mockFactory.create(3)).thenReturn(valueFor3);
     SslContextProvider val = map.get(3);
     assertThat(val).isSameInstanceAs(valueFor3);
     verify(valueFor3, never()).close();
@@ -73,8 +74,8 @@ public class ReferenceCountingSslContextProviderMapTest {
   public void referenceCountingMap_distinctElements() throws InterruptedException {
     SslContextProvider valueFor3 = getTypedMock();
     SslContextProvider valueFor4 = getTypedMock();
-    when(mockFactory.createSslContextProvider(3)).thenReturn(valueFor3);
-    when(mockFactory.createSslContextProvider(4)).thenReturn(valueFor4);
+    when(mockFactory.create(3)).thenReturn(valueFor3);
+    when(mockFactory.create(4)).thenReturn(valueFor4);
     SslContextProvider val3 = map.get(3);
     assertThat(val3).isSameInstanceAs(valueFor3);
     SslContextProvider val4 = map.get(4);
@@ -91,8 +92,8 @@ public class ReferenceCountingSslContextProviderMapTest {
       throws InterruptedException {
     SslContextProvider valueFor3 = getTypedMock();
     SslContextProvider valueFor4 = getTypedMock();
-    when(mockFactory.createSslContextProvider(3)).thenReturn(valueFor3);
-    when(mockFactory.createSslContextProvider(4)).thenReturn(valueFor4);
+    when(mockFactory.create(3)).thenReturn(valueFor3);
+    when(mockFactory.create(4)).thenReturn(valueFor4);
     SslContextProvider unused = map.get(3);
     SslContextProvider val4 = map.get(4);
     // now provide wrong key (3) and value (val4) combination
@@ -107,7 +108,7 @@ public class ReferenceCountingSslContextProviderMapTest {
   @Test
   public void referenceCountingMap_excessRelease_expectException() throws InterruptedException {
     SslContextProvider valueFor4 = getTypedMock();
-    when(mockFactory.createSslContextProvider(4)).thenReturn(valueFor4);
+    when(mockFactory.create(4)).thenReturn(valueFor4);
     SslContextProvider val = map.get(4);
     assertThat(val).isSameInstanceAs(valueFor4);
     // at this point ref-count is 1
@@ -124,7 +125,7 @@ public class ReferenceCountingSslContextProviderMapTest {
   @Test
   public void referenceCountingMap_releaseAndGet_differentInstance() throws InterruptedException {
     SslContextProvider valueFor4 = getTypedMock();
-    when(mockFactory.createSslContextProvider(4)).thenReturn(valueFor4);
+    when(mockFactory.create(4)).thenReturn(valueFor4);
     SslContextProvider val = map.get(4);
     assertThat(val).isSameInstanceAs(valueFor4);
     // at this point ref-count is 1
@@ -132,7 +133,7 @@ public class ReferenceCountingSslContextProviderMapTest {
     // at this point ref-count is 0 and val is removed
     // should get another instance for 4
     SslContextProvider valueFor4a = getTypedMock();
-    when(mockFactory.createSslContextProvider(4)).thenReturn(valueFor4a);
+    when(mockFactory.create(4)).thenReturn(valueFor4a);
     val = map.get(4);
     assertThat(val).isSameInstanceAs(valueFor4a);
     // verify it is a different instance from before

xds/src/test/java/io/grpc/xds/internal/sds/ServerSslContextProviderFactoryTest.java

@@ -42,7 +42,7 @@ public class ServerSslContextProviderFactoryTest {
             SERVER_1_KEY_FILE, SERVER_1_PEM_FILE, CA_PEM_FILE);
 
     SslContextProvider sslContextProvider =
-        serverSslContextProviderFactory.createSslContextProvider(downstreamTlsContext);
+        serverSslContextProviderFactory.create(downstreamTlsContext);
     assertThat(sslContextProvider).isNotNull();
   }
 
@@ -57,7 +57,7 @@ public class ServerSslContextProviderFactoryTest {
 
     try {
       SslContextProvider unused =
-          serverSslContextProviderFactory.createSslContextProvider(downstreamTlsContext);
+          serverSslContextProviderFactory.create(downstreamTlsContext);
       Assert.fail("no exception thrown");
     } catch (UnsupportedOperationException expected) {
       assertThat(expected)
@@ -77,7 +77,7 @@ public class ServerSslContextProviderFactoryTest {
 
     try {
       SslContextProvider unused =
-          serverSslContextProviderFactory.createSslContextProvider(downstreamTlsContext);
+          serverSslContextProviderFactory.create(downstreamTlsContext);
       Assert.fail("no exception thrown");
     } catch (UnsupportedOperationException expected) {
       assertThat(expected)

xds/src/test/java/io/grpc/xds/internal/sds/TlsContextManagerTest.java

@@ -32,7 +32,7 @@ import static org.mockito.Mockito.when;
 
 import io.grpc.xds.EnvoyServerProtoData.DownstreamTlsContext;
 import io.grpc.xds.EnvoyServerProtoData.UpstreamTlsContext;
-import io.grpc.xds.internal.sds.ReferenceCountingSslContextProviderMap.SslContextProviderFactory;
+import io.grpc.xds.internal.sds.ReferenceCountingMap.ValueFactory;
 import java.lang.reflect.Field;
 import org.junit.Before;
 import org.junit.Rule;
@@ -49,9 +49,9 @@ public class TlsContextManagerTest {
 
   @Rule public final MockitoRule mockitoRule = MockitoJUnit.rule();
 
-  @Mock SslContextProviderFactory<UpstreamTlsContext> mockClientFactory;
+  @Mock ValueFactory<UpstreamTlsContext, SslContextProvider> mockClientFactory;
 
-  @Mock SslContextProviderFactory<DownstreamTlsContext> mockServerFactory;
+  @Mock ValueFactory<DownstreamTlsContext, SslContextProvider> mockServerFactory;
 
   @Before
   public void clearInstance() throws NoSuchFieldException, IllegalAccessException {
@@ -141,7 +141,7 @@ public class TlsContextManagerTest {
     TlsContextManagerImpl tlsContextManagerImpl =
         new TlsContextManagerImpl(mockClientFactory, mockServerFactory);
     SslContextProvider mockProvider = mock(SslContextProvider.class);
-    when(mockServerFactory.createSslContextProvider(downstreamTlsContext)).thenReturn(mockProvider);
+    when(mockServerFactory.create(downstreamTlsContext)).thenReturn(mockProvider);
     SslContextProvider serverSecretProvider =
         tlsContextManagerImpl.findOrCreateServerSslContextProvider(downstreamTlsContext);
     assertThat(serverSecretProvider).isSameInstanceAs(mockProvider);
@@ -160,7 +160,7 @@ public class TlsContextManagerTest {
     TlsContextManagerImpl tlsContextManagerImpl =
         new TlsContextManagerImpl(mockClientFactory, mockServerFactory);
     SslContextProvider mockProvider = mock(SslContextProvider.class);
-    when(mockClientFactory.createSslContextProvider(upstreamTlsContext)).thenReturn(mockProvider);
+    when(mockClientFactory.create(upstreamTlsContext)).thenReturn(mockProvider);
     SslContextProvider clientSecretProvider =
         tlsContextManagerImpl.findOrCreateClientSslContextProvider(upstreamTlsContext);
     assertThat(clientSecretProvider).isSameInstanceAs(mockProvider);