clean(core): Factor out ResourceHasher

enola-dev · Jan 4, 2025 · cf2305d · cf2305d
1 parent b72f637
commit cf2305d
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Showing 4 changed files with 66 additions and 24 deletions.
diff --git a/java/dev/enola/common/io/hashbrown/IntegrityValidatingDelegatingResource.java b/java/dev/enola/common/io/hashbrown/IntegrityValidatingDelegatingResource.java
@@ -17,7 +17,6 @@
  */
 package dev.enola.common.io.hashbrown;
 
-import com.google.common.hash.Hasher;
 import com.google.common.io.ByteSource;
 import com.google.common.io.CharSource;
 
@@ -72,31 +71,19 @@ public CharSource charSource() {
     private synchronized void validate() {
         if (validated) return;
 
-        var delegateByteSource = delegate.byteSource();
-        var hashFunction = Multihashes.toGuavaHashFunction(expectedHash.multihash());
-
-        Hasher hasher;
-        var optSize = delegateByteSource.sizeIfKnown();
-        if (optSize.isPresent()) hasher = hashFunction.newHasher(Math.toIntExact(optSize.get()));
-        else hasher = hashFunction.newHasher();
-
-        try (var is = delegateByteSource.openBufferedStream()) {
-            var read = is.read();
-            while (read != -1) {
-                hasher.putByte((byte) read);
-                read = is.read();
+        var resourceHasher = new ResourceHasher();
+        try {
+            var actualHash = resourceHasher.hash(delegate, expectedHash.multihash().getType());
+            if (!expectedHash.multihash().equals(actualHash)) {
+                throw new IntegrityViolationException(
+                        "Expected "
+                                + expectedHash
+                                + " but got "
+                                + Multihashes.toString(actualHash, expectedHash.multibase()));
             }
         } catch (IOException e) {
             throw new UncheckedIOException(e);
         }
-        var hashCode = hasher.hash();
-        var actualBytes = hashCode.asBytes();
-        var actualHash = expectedHash.copy(actualBytes);
-
-        if (!expectedHash.equals(actualHash)) {
-            throw new IntegrityViolationException(
-                    "Expected " + expectedHash + " but got " + actualHash);
-        }
 
         validated = true;
     }

diff --git a/java/dev/enola/common/io/hashbrown/MultihashWithMultibase.java b/java/dev/enola/common/io/hashbrown/MultihashWithMultibase.java
@@ -56,6 +56,10 @@ public Multihash multihash() {
         return multihash;
     }
 
+    public Multibase.Base multibase() {
+        return multibase;
+    }
+
     @Override
     public boolean equals(Object o) {
         if (!(o instanceof MultihashWithMultibase other)) return false;

diff --git a/java/dev/enola/common/io/hashbrown/Multihashes.java b/java/dev/enola/common/io/hashbrown/Multihashes.java
@@ -26,8 +26,7 @@
 /** Extension methods for {@link io.ipfs.multihash.Multihash}. */
 public final class Multihashes {
 
-    public static HashFunction toGuavaHashFunction(Multihash multihash) {
-        var type = multihash.getType();
+    public static HashFunction toGuavaHashFunction(Multihash.Type type) {
         return switch (type) {
             // NB: Please BEWARE of what types are added here; the (sub)selection is intentional!
 

diff --git a/java/dev/enola/common/io/hashbrown/ResourceHasher.java b/java/dev/enola/common/io/hashbrown/ResourceHasher.java
@@ -0,0 +1,52 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Copyright 2025 The Enola <https://enola.dev> 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
+ *
+ *     https://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 dev.enola.common.io.hashbrown;
+
+import com.google.common.hash.Hasher;
+
+import dev.enola.common.io.resource.Resource;
+
+import io.ipfs.multihash.Multihash;
+
+import java.io.IOException;
+
+public class ResourceHasher {
+
+    @SuppressWarnings("UnstableApiUsage")
+    public Multihash hash(Resource resource, Multihash.Type hashType) throws IOException {
+        var hashFunction = Multihashes.toGuavaHashFunction(hashType);
+        var byteSource = resource.byteSource();
+
+        Hasher hasher;
+        var optSize = byteSource.sizeIfKnown();
+        if (optSize.isPresent()) hasher = hashFunction.newHasher(Math.toIntExact(optSize.get()));
+        else hasher = hashFunction.newHasher();
+
+        try (var is = byteSource.openBufferedStream()) {
+            var read = is.read();
+            while (read != -1) {
+                hasher.putByte((byte) read);
+                read = is.read();
+            }
+        }
+
+        var hashCode = hasher.hash();
+        var actualBytes = hashCode.asBytes();
+        return new Multihash(hashType, actualBytes);
+    }
+}