Use Caffeine for request aggregation

pom.xml

@@ -42,6 +42,7 @@
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <guava.version>31.0.1-jre</guava.version>
+		<caffeine.version>3.0.5</caffeine.version>
         <jwt.version>3.18.2</jwt.version>
         <cryptolib.version>2.0.2</cryptolib.version>
 
@@ -70,6 +71,11 @@
             <artifactId>guava</artifactId>
             <version>${guava.version}</version>
         </dependency>
+		<dependency>
+			<groupId>com.github.ben-manes.caffeine</groupId>
+			<artifactId>caffeine</artifactId>
+			<version>${caffeine.version}</version>
+		</dependency>
         <dependency>
             <groupId>com.auth0</groupId>
             <artifactId>java-jwt</artifactId>

src/main/java/module-info.java

@@ -2,6 +2,7 @@
 	exports org.cryptomator.cloudaccess;
 	exports org.cryptomator.cloudaccess.api;
 	exports org.cryptomator.cloudaccess.api.exceptions;
+	exports org.cryptomator.cloudaccess.requestdecorator;
 
 	requires java.xml;
 	requires com.google.common;
@@ -11,4 +12,5 @@
 	requires okhttp.digest;
 	requires okio;
 	requires com.auth0.jwt;
+	requires com.github.benmanes.caffeine;
 }

src/main/java/org/cryptomator/cloudaccess/CloudAccess.java

@@ -13,6 +13,7 @@
 import org.cryptomator.cloudaccess.api.exceptions.VaultVerificationFailedException;
 import org.cryptomator.cloudaccess.api.exceptions.VaultVersionVerificationFailedException;
 import org.cryptomator.cloudaccess.localfs.LocalFsCloudProvider;
+import org.cryptomator.cloudaccess.requestdecorator.CloudProviderDecoratorFactory;
 import org.cryptomator.cloudaccess.vaultformat8.VaultFormat8ProviderDecorator;
 import org.cryptomator.cloudaccess.webdav.WebDavCloudProvider;
 import org.cryptomator.cloudaccess.webdav.WebDavCredential;
@@ -59,9 +60,12 @@ public static CloudProvider vaultFormat8GCMCloudAccess(CloudProvider cloudProvid
 
 			verifyVaultFormat8GCMConfig(cloudProvider, pathToVault, rawKey);
 
-			VaultFormat8ProviderDecorator provider = new VaultFormat8ProviderDecorator(cloudProvider, pathToVault.resolve("d"), cryptor);
-			provider.initialize();
-			return new MetadataCachingProviderDecorator(provider);
+			var decoratedCloudProvider = new CloudProviderDecoratorFactory().get(cloudProvider, cloudProvider.cachingCapability());
+
+			VaultFormat8ProviderDecorator vaultFormat8Provider = new VaultFormat8ProviderDecorator(decoratedCloudProvider, pathToVault.resolve("d"), cryptor);
+			vaultFormat8Provider.initialize();
+
+			return vaultFormat8Provider;
 		} catch (NoSuchAlgorithmException e) {
 			throw new IllegalStateException("JVM doesn't supply a CSPRNG", e);
 		} catch (InterruptedException e) {

src/main/java/org/cryptomator/cloudaccess/requestdecorator/CloudProviderDecorator.java

@@ -0,0 +1,77 @@
+package org.cryptomator.cloudaccess.requestdecorator;
+
+import org.cryptomator.cloudaccess.api.CloudItemList;
+import org.cryptomator.cloudaccess.api.CloudItemMetadata;
+import org.cryptomator.cloudaccess.api.CloudPath;
+import org.cryptomator.cloudaccess.api.CloudProvider;
+import org.cryptomator.cloudaccess.api.ProgressListener;
+import org.cryptomator.cloudaccess.api.Quota;
+
+import java.io.InputStream;
+import java.time.Instant;
+import java.util.Optional;
+import java.util.concurrent.CompletionStage;
+
+abstract class CloudProviderDecorator implements CloudProvider {
+
+	private final CloudProvider delegate;
+
+	public CloudProviderDecorator(CloudProvider delegate) {
+		this.delegate = delegate;
+	}
+
+	@Override
+	public CompletionStage<CloudItemMetadata> itemMetadata(CloudPath node) {
+		return delegate.itemMetadata(node);
+	}
+
+	@Override
+	public CompletionStage<Quota> quota(CloudPath folder) {
+		return delegate.quota(folder);
+	}
+
+	@Override
+	public CompletionStage<CloudItemList> list(CloudPath folder, Optional<String> pageToken) {
+		return delegate.list(folder, pageToken);
+	}
+
+	@Override
+	public CompletionStage<InputStream> read(CloudPath file, long offset, long count, ProgressListener progressListener) {
+		return delegate.read(file, offset, count, progressListener);
+	}
+
+	@Override
+	public CompletionStage<Void> write(CloudPath file, boolean replace, InputStream data, long size, Optional<Instant> lastModified, ProgressListener progressListener) {
+		return delegate.write(file, replace, data, size, lastModified, progressListener);
+	}
+
+	@Override
+	public CompletionStage<CloudPath> createFolder(CloudPath folder) {
+		return delegate.createFolder(folder);
+	}
+
+	@Override
+	public CompletionStage<Void> deleteFile(CloudPath file) {
+		return delegate.deleteFile(file);
+	}
+
+	@Override
+	public CompletionStage<Void> deleteFolder(CloudPath folder) {
+		return delegate.deleteFolder(folder);
+	}
+
+	@Override
+	public CompletionStage<CloudPath> move(CloudPath source, CloudPath target, boolean replace) {
+		return delegate.move(source, target, replace);
+	}
+
+	@Override
+	public boolean cachingCapability() {
+		return delegate.cachingCapability();
+	}
+
+	@Override
+	public CompletionStage<Void> pollRemoteChanges() {
+		return delegate.pollRemoteChanges();
+	}
+}

src/main/java/org/cryptomator/cloudaccess/requestdecorator/CloudProviderDecoratorFactory.java

@@ -0,0 +1,18 @@
+package org.cryptomator.cloudaccess.requestdecorator;
+
+import org.cryptomator.cloudaccess.api.CloudProvider;
+
+/**
+ * Factory class to add a caching or request-deduplication decorator around an existing {@link CloudProvider}.
+ */
+public class CloudProviderDecoratorFactory {
+
+	public CloudProvider get(CloudProvider cloudProvider, boolean cloudCachingCapability) {
+		if (cloudCachingCapability) {
+			var quotaCachingDecorator = new QuotaRequestCachingDecorator(cloudProvider);
+			return new MetadataRequestDeduplicationDecorator(quotaCachingDecorator);
+		} else {
+			return new MetadataCachingProviderDecorator(cloudProvider);
+		}
+	}
+}

src/main/java/org/cryptomator/cloudaccess/MetadataCachingProviderDecorator.java → src/main/java/org/cryptomator/cloudaccess/requestdecorator/MetadataCachingProviderDecorator.java

@@ -1,4 +1,4 @@
-package org.cryptomator.cloudaccess;
+package org.cryptomator.cloudaccess.requestdecorator;
 
 import com.google.common.cache.Cache;
 import com.google.common.cache.CacheBuilder;
@@ -20,7 +20,7 @@
 import java.util.concurrent.CompletionStage;
 import java.util.concurrent.ExecutionException;
 
-public class MetadataCachingProviderDecorator implements CloudProvider {
+class MetadataCachingProviderDecorator implements CloudProvider {
 
 	private final static int DEFAULT_CACHE_TIMEOUT_SECONDS = 10;
 
@@ -93,7 +93,7 @@ public CompletionStage<CloudItemList> list(CloudPath folder, Optional<String> pa
 					evictFromItemAndItemListCacheIncludingDescendants(folder);
 				} else if (delegate.cachingCapability()) {
 					evictFromItemListCache(entry);
-				} else if (exception == null) {
+				} else if (!delegate.cachingCapability() && exception == null) {
 					evictFromItemAndItemListCacheIncludingDescendants(folder);
 					assert cloudItemList != null;
 					cloudItemList.getItems().forEach(metadata -> cachedItemMetadataRequests.put(metadata.getPath(), CompletableFuture.completedFuture(metadata)));

src/main/java/org/cryptomator/cloudaccess/requestdecorator/MetadataRequestDeduplicationDecorator.java

@@ -0,0 +1,55 @@
+package org.cryptomator.cloudaccess.requestdecorator;
+
+import com.github.benmanes.caffeine.cache.AsyncCache;
+import com.github.benmanes.caffeine.cache.Caffeine;
+import org.cryptomator.cloudaccess.api.CloudItemList;
+import org.cryptomator.cloudaccess.api.CloudItemMetadata;
+import org.cryptomator.cloudaccess.api.CloudPath;
+import org.cryptomator.cloudaccess.api.CloudProvider;
+
+import java.time.Duration;
+import java.util.Optional;
+import java.util.concurrent.CompletionStage;
+
+/**
+ * Decorates an existing CloudProvider by deduplicating identical itemMetadata and list-requests so that the delegate is called only once until the future is completed.
+ */
+class MetadataRequestDeduplicationDecorator extends CloudProviderDecorator {
+
+
+	// visible for testing
+	final AsyncCache<CloudPath, CloudItemMetadata> cachedItemMetadataRequests;
+	final AsyncCache<ItemListEntry, CloudItemList> cachedItemListRequests;
+
+	private final CloudProvider delegate;
+
+	public MetadataRequestDeduplicationDecorator(CloudProvider delegate) {
+		this(delegate, //
+				Caffeine.newBuilder().expireAfterWrite(Duration.ofSeconds(0)).buildAsync(), //
+				Caffeine.newBuilder().expireAfterWrite(Duration.ofSeconds(0)).buildAsync());
+	}
+
+	MetadataRequestDeduplicationDecorator(
+			CloudProvider delegate, //
+			AsyncCache<CloudPath, CloudItemMetadata> cachedItemMetadataRequests, //
+			AsyncCache<ItemListEntry, CloudItemList> cachedItemListRequests) {
+		super(delegate);
+		this.delegate = delegate;
+		this.cachedItemMetadataRequests = cachedItemMetadataRequests;
+		this.cachedItemListRequests = cachedItemListRequests;
+	}
+
+	@Override
+	public CompletionStage<CloudItemMetadata> itemMetadata(CloudPath node) {
+		return cachedItemMetadataRequests.get(node, k -> delegate.itemMetadata(k).toCompletableFuture().join());
+	}
+
+	@Override
+	public CompletionStage<CloudItemList> list(CloudPath folder, Optional<String> pageToken) {
+		var entry = new ItemListEntry(folder, pageToken);
+		return cachedItemListRequests.get(entry, k -> delegate.list(k.path, k.pageToken).toCompletableFuture().join());
+	}
+
+	record ItemListEntry(CloudPath path, Optional<String> pageToken) {
+	}
+}

src/main/java/org/cryptomator/cloudaccess/requestdecorator/QuotaRequestCachingDecorator.java

@@ -0,0 +1,47 @@
+package org.cryptomator.cloudaccess.requestdecorator;
+
+import com.github.benmanes.caffeine.cache.AsyncCache;
+import com.github.benmanes.caffeine.cache.Caffeine;
+import org.cryptomator.cloudaccess.api.CloudPath;
+import org.cryptomator.cloudaccess.api.CloudProvider;
+import org.cryptomator.cloudaccess.api.Quota;
+import org.cryptomator.cloudaccess.api.exceptions.NotFoundException;
+import org.cryptomator.cloudaccess.api.exceptions.QuotaNotAvailableException;
+
+import java.time.Duration;
+import java.util.concurrent.CompletionStage;
+
+/**
+ * Decorates an existing CloudProvider by caching quota-requests for a duration of default 10 seconds (can be set using <code>org.cryptomator.cloudaccess.metadatacachingprovider.timeoutSeconds</code>).
+ */
+class QuotaRequestCachingDecorator extends CloudProviderDecorator {
+
+	private final static int DEFAULT_CACHE_TIMEOUT_SECONDS = 10;
+
+	// visible for testing
+	final AsyncCache<CloudPath, Quota> quotaCache;
+
+	private final CloudProvider delegate;
+
+	public QuotaRequestCachingDecorator(CloudProvider delegate) {
+		this(delegate, Caffeine
+				.newBuilder()
+				.expireAfterWrite(Duration.ofSeconds(Integer.getInteger("org.cryptomator.cloudaccess.metadatacachingprovider.timeoutSeconds", DEFAULT_CACHE_TIMEOUT_SECONDS)))
+				.buildAsync());
+	}
+
+	QuotaRequestCachingDecorator(CloudProvider delegate, AsyncCache<CloudPath, Quota> quotaCache) {
+		super(delegate);
+		this.delegate = delegate;
+		this.quotaCache = quotaCache;
+	}
+
+	@Override
+	public CompletionStage<Quota> quota(CloudPath folder) {
+		return quotaCache.get(folder, k -> delegate.quota(k).whenComplete((metadata, throwable) -> {
+			if (throwable != null && !(throwable instanceof NotFoundException) && !(throwable instanceof QuotaNotAvailableException)) {
+				quotaCache.synchronous().invalidate(folder);
+			}
+		}).toCompletableFuture().join());
+	}
+}

src/test/java/org/cryptomator/cloudaccess/MetadataCachingProviderDecoratorTest.java → src/test/java/org/cryptomator/cloudaccess/requestdecorator/MetadataCachingProviderDecoratorTest.java

@@ -1,4 +1,4 @@
-package org.cryptomator.cloudaccess;
+package org.cryptomator.cloudaccess.requestdecorator;
 
 import org.cryptomator.cloudaccess.api.CloudItemList;
 import org.cryptomator.cloudaccess.api.CloudItemMetadata;
@@ -8,6 +8,7 @@
 import org.cryptomator.cloudaccess.api.ProgressListener;
 import org.cryptomator.cloudaccess.api.exceptions.CloudProviderException;
 import org.cryptomator.cloudaccess.api.exceptions.NotFoundException;
+import org.cryptomator.cloudaccess.requestdecorator.MetadataCachingProviderDecorator;
 import org.hamcrest.CoreMatchers;
 import org.hamcrest.MatcherAssert;
 import org.junit.jupiter.api.Assertions;

src/test/java/org/cryptomator/cloudaccess/MetadataRequestAggregatorProviderDecoratorTest.java → src/test/java/org/cryptomator/cloudaccess/requestdecorator/MetadataRequestAggregatorProviderDecoratorTest.java

@@ -1,4 +1,4 @@
-package org.cryptomator.cloudaccess;
+package org.cryptomator.cloudaccess.requestdecorator;
 
 import com.google.common.cache.Cache;
 import com.google.common.cache.CacheBuilder;
@@ -10,6 +10,7 @@
 import org.cryptomator.cloudaccess.api.ProgressListener;
 import org.cryptomator.cloudaccess.api.exceptions.CloudProviderException;
 import org.cryptomator.cloudaccess.api.exceptions.NotFoundException;
+import org.cryptomator.cloudaccess.requestdecorator.MetadataCachingProviderDecorator;
 import org.hamcrest.CoreMatchers;
 import org.hamcrest.MatcherAssert;
 import org.junit.jupiter.api.Assertions;