ISSUE_469: Add '_MM' versions for all SHA-algorithms, which prevents…

src/main/java/org/apache/maven/buildcache/hash/Hash.java

@@ -57,4 +57,12 @@ public interface Factory {
 
         Checksum checksum(int count);
     }
+
+    /**
+     * Memory policy
+     */
+    public enum MemoryPolicy {
+        Standard,
+        MemoryMappedBuffers
+    }
 }

src/main/java/org/apache/maven/buildcache/hash/HashFactory.java

@@ -28,14 +28,18 @@
  * HashFactory
  */
 public enum HashFactory {
-    SHA1(new SHA("SHA-1")),
-    SHA256(new SHA("SHA-256")),
-    SHA384(new SHA("SHA-384")),
-    SHA512(new SHA("SHA-512")),
-    XX(new Zah("XX", LongHashFunction.xx(), Zah.MemoryPolicy.Standard)),
-    XXMM(new Zah("XXMM", LongHashFunction.xx(), Zah.MemoryPolicy.MemoryMappedBuffers)),
-    METRO(new Zah("METRO", LongHashFunction.metro(), Zah.MemoryPolicy.Standard)),
-    METRO_MM(new Zah("METRO+MM", LongHashFunction.metro(), Zah.MemoryPolicy.MemoryMappedBuffers));
+    SHA1(new SHA("SHA-1", Hash.MemoryPolicy.Standard)),
+    SHA1_MM(new SHA("SHA-1", Hash.MemoryPolicy.MemoryMappedBuffers)),
+    SHA256(new SHA("SHA-256", Hash.MemoryPolicy.Standard)),
+    SHA256_MM(new SHA("SHA-256", Hash.MemoryPolicy.MemoryMappedBuffers)),
+    SHA384(new SHA("SHA-384", Hash.MemoryPolicy.Standard)),
+    SHA384_MM(new SHA("SHA-384", Hash.MemoryPolicy.MemoryMappedBuffers)),
+    SHA512(new SHA("SHA-512", Hash.MemoryPolicy.Standard)),
+    SHA512_MM(new SHA("SHA-512", Hash.MemoryPolicy.MemoryMappedBuffers)),
+    XX(new Zah("XX", LongHashFunction.xx(), Hash.MemoryPolicy.Standard)),
+    XXMM(new Zah("XXMM", LongHashFunction.xx(), Hash.MemoryPolicy.MemoryMappedBuffers)),
+    METRO(new Zah("METRO", LongHashFunction.metro(), Hash.MemoryPolicy.Standard)),
+    METRO_MM(new Zah("METRO+MM", LongHashFunction.metro(), Hash.MemoryPolicy.MemoryMappedBuffers));
 
     private static final Map<String, HashFactory> LOOKUP = new HashMap<>();
 

src/main/java/org/apache/maven/buildcache/hash/SHA.java

@@ -19,10 +19,14 @@
 package org.apache.maven.buildcache.hash;
 
 import java.io.IOException;
+import java.nio.channels.FileChannel;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.security.MessageDigest;
 
+import static java.nio.channels.FileChannel.MapMode.READ_ONLY;
+import static java.nio.file.StandardOpenOption.READ;
+
 /**
  * SHA
  */
@@ -32,9 +36,11 @@ public class SHA implements Hash.Factory {
     private static final ThreadLocal<MessageDigest> CHECKSUM = new ThreadLocal<>();
 
     private final String algorithm;
+    private final Hash.MemoryPolicy memoryPolicy;
 
-    SHA(String algorithm) {
+    SHA(String algorithm, Hash.MemoryPolicy memoryPolicy) {
         this.algorithm = algorithm;
+        this.memoryPolicy = memoryPolicy != null ? memoryPolicy : Hash.MemoryPolicy.Standard;
     }
 
     @Override
@@ -44,7 +50,12 @@ public String getAlgorithm() {
 
     @Override
     public Hash.Algorithm algorithm() {
-        return new SHA.Algorithm(ThreadLocalDigest.get(ALGORITHM, algorithm));
+        switch (memoryPolicy) {
+            case MemoryMappedBuffers:
+                return new AlgorithmWithMM(ThreadLocalDigest.get(ALGORITHM, algorithm));
+            default:
+                return new SHA.Algorithm(ThreadLocalDigest.get(ALGORITHM, algorithm));
+        }
     }
 
     @Override
@@ -71,6 +82,28 @@ public byte[] hash(Path path) throws IOException {
         }
     }
 
+    private static class AlgorithmWithMM implements Hash.Algorithm {
+        private final MessageDigest digest;
+
+        private AlgorithmWithMM(MessageDigest digest) {
+            this.digest = digest;
+        }
+
+        @Override
+        public byte[] hash(byte[] array) {
+            return digest.digest(array);
+        }
+
+        @Override
+        public byte[] hash(Path path) throws IOException {
+            try (FileChannel channel = FileChannel.open(path, READ);
+                    CloseableBuffer buffer = CloseableBuffer.mappedBuffer(channel, READ_ONLY)) {
+                digest.update(buffer.getBuffer());
+                return digest.digest();
+            }
+        }
+    }
+
     private static class Checksum implements Hash.Checksum {
 
         private final MessageDigest digest;

src/main/java/org/apache/maven/buildcache/hash/Zah.java

@@ -34,19 +34,14 @@
  */
 public class Zah implements Hash.Factory {
 
-    public enum MemoryPolicy {
-        Standard,
-        MemoryMappedBuffers
-    }
-
     private final String name;
     private final LongHashFunction hash;
-    private final MemoryPolicy memoryPolicy;
+    private final Hash.MemoryPolicy memoryPolicy;
 
-    public Zah(String name, LongHashFunction hash, MemoryPolicy memoryPolicy) {
+    public Zah(String name, LongHashFunction hash, Hash.MemoryPolicy memoryPolicy) {
         this.name = name;
         this.hash = hash;
-        this.memoryPolicy = memoryPolicy != null ? memoryPolicy : MemoryPolicy.Standard;
+        this.memoryPolicy = memoryPolicy != null ? memoryPolicy : Hash.MemoryPolicy.Standard;
     }
 
     @Override

src/test/java/org/apache/maven/buildcache/checksum/SHAHashTest.java

@@ -36,11 +36,16 @@
  * specific language governing permissions and limitations
  * under the License.
  */
+import java.io.IOException;
 import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
 
 import org.apache.maven.buildcache.hash.HashAlgorithm;
 import org.apache.maven.buildcache.hash.HashChecksum;
+import org.apache.maven.buildcache.hash.HashFactory;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
 
 import static org.apache.maven.buildcache.hash.HashFactory.SHA256;
 import static org.junit.jupiter.api.Assertions.assertEquals;
@@ -57,22 +62,35 @@ class SHAHashTest {
     private static final String FULL_CHECKSUM = "7305db9b2abccd706c256db3d97e5ff48d677cfe4d3a5904afb7da0e3950e1e2";
 
     private static final HashAlgorithm ALGORITHM = SHA256.createAlgorithm();
+    private static final HashAlgorithm ALGORITHM_MM = HashFactory.SHA256_MM.createAlgorithm();
+
     private static final HashChecksum CHECKSUM = SHA256.createChecksum(0);
 
+    @TempDir
+    Path tempDir;
+
     @Test
     void testEmptyArray() {
         byte[] emptyArray = new byte[0];
-        String hash = ALGORITHM.hash(emptyArray);
-        assertEquals(EMPTY_HASH, hash);
+        assertEquals(EMPTY_HASH, ALGORITHM.hash(emptyArray));
     }
 
     @Test
     void testSimpleHash() {
         String helloHash = ALGORITHM.hash(HELLO_ARRAY);
         assertEquals(HELLO_HASH, helloHash);
 
-        String worldHash = ALGORITHM.hash(WORLD_ARRAY);
-        assertEquals(WORLD_HASH, worldHash);
+        assertEquals(WORLD_HASH, ALGORITHM.hash(WORLD_ARRAY));
+        assertEquals(WORLD_HASH, ALGORITHM_MM.hash(WORLD_ARRAY));
+    }
+
+    @Test
+    void testFileHash() throws IOException {
+        Path testFile = tempDir.resolve("SHAHashTest.txt");
+        Files.write(testFile, HELLO_ARRAY);
+
+        assertEquals(HELLO_HASH, ALGORITHM.hash(testFile));
+        assertEquals(HELLO_HASH, ALGORITHM_MM.hash(testFile));
     }
 
     @Test

src/test/java/org/apache/maven/buildcache/hash/PerfTest.java

@@ -82,6 +82,11 @@ public String sha256(HashState state) throws IOException {
         return doTest(HashFactory.SHA256, state);
     }
 
+    @Benchmark
+    public String sha256mm(HashState state) throws IOException {
+        return doTest(HashFactory.SHA256_MM, state);
+    }
+
     @Benchmark
     public String xx(HashState state) throws IOException {
         return doTest(HashFactory.XX, state);