Duplicate code reduction part 2: clean up checksum classes (#6484)

* Duplicate code reduction part 2: clean up checksum classes

* Fix build

Author: zoewangg

build-tools/src/main/resources/software/amazon/awssdk/spotbugs-suppressions.xml

@@ -302,14 +302,12 @@
     </Match>
 
     <!-- Retrieves and updates crc value in update() -->
-     <Match>
-         <Or>
-             <Class name="software.amazon.awssdk.checksums.internal.SdkCrc32CChecksum"/>
-             <Class name="software.amazon.awssdk.checksums.internal.SdkCrc32Checksum"/>
-             <Class name="software.amazon.awssdk.core.internal.checksums.factory.SdkCrc32C"/>
-             <Class name="software.amazon.awssdk.core.internal.checksums.factory.SdkCrc32"/>
-         </Or>
-         <Bug pattern="SA_FIELD_SELF_ASSIGNMENT"/>
+    <Match>
+        <Or>
+            <Class name="software.amazon.awssdk.checksums.internal.SdkCrc32CChecksum"/>
+            <Class name="software.amazon.awssdk.checksums.internal.SdkCrc32Checksum"/>
+        </Or>
+        <Bug pattern="SA_FIELD_SELF_ASSIGNMENT"/>
     </Match>
 
     <!-- Suppress existing blocking call. -->

core/auth-crt/src/test/java/software/amazon/awssdk/authcrt/signer/internal/checksum/CrtBasedChecksumTest.java

@@ -15,85 +15,23 @@
 
 package software.amazon.awssdk.core.checksums;
 
-import static software.amazon.awssdk.core.internal.util.HttpChecksumUtils.longToByte;
-
-import java.lang.reflect.Method;
-import java.util.Arrays;
-import java.util.zip.Checksum;
-import software.amazon.awssdk.annotations.SdkInternalApi;
-import software.amazon.awssdk.core.internal.checksums.factory.CrtBasedChecksumProvider;
-import software.amazon.awssdk.core.internal.checksums.factory.SdkCrc32C;
+import software.amazon.awssdk.annotations.SdkProtectedApi;
+import software.amazon.awssdk.checksums.DefaultChecksumAlgorithm;
+import software.amazon.awssdk.core.internal.checksums.LegacyDelegatingChecksum;
 
 /**
  * Implementation of {@link SdkChecksum} to calculate an CRC32C checksum.
+ * <p>
+ * Implementor notes: this should've been an internal API, but we can't change it now since it's not within the internal
+ * subpackage.
+ *
  * @deprecated this class is deprecated and subject to removal.
  */
 @Deprecated
-@SdkInternalApi
-public class Crc32CChecksum implements SdkChecksum {
-
-    private Checksum crc32c;
-    private Checksum lastMarkedCrc32C;
-    private final boolean isCrtBasedChecksum;
+@SdkProtectedApi
+public class Crc32CChecksum extends LegacyDelegatingChecksum {
 
-    /**
-     * Creates CRT Based Crc32C checksum if Crt classpath for Crc32c is loaded, else create Sdk Implemented Crc32c
-     */
     public Crc32CChecksum() {
-        crc32c = CrtBasedChecksumProvider.createCrc32C();
-        isCrtBasedChecksum = crc32c != null;
-        if (!isCrtBasedChecksum) {
-            crc32c = SdkCrc32C.create();
-        }
-    }
-
-    @Override
-    public byte[] getChecksumBytes() {
-        return Arrays.copyOfRange(longToByte(crc32c.getValue()), 4, 8);
-    }
-
-
-    @Override
-    public void mark(int readLimit) {
-        this.lastMarkedCrc32C = cloneChecksum(crc32c);
-    }
-
-    @Override
-    public void update(int b) {
-        crc32c.update(b);
-    }
-
-    @Override
-    public void update(byte[] b, int off, int len) {
-        crc32c.update(b, off, len);
-    }
-
-    @Override
-    public long getValue() {
-        return crc32c.getValue();
-    }
-
-    @Override
-    public void reset() {
-        if (lastMarkedCrc32C == null) {
-            crc32c.reset();
-        } else {
-            crc32c = cloneChecksum(lastMarkedCrc32C);
-        }
-    }
-
-
-    private Checksum cloneChecksum(Checksum checksum) {
-        if (isCrtBasedChecksum) {
-            try {
-                Method method = checksum.getClass().getDeclaredMethod("clone");
-                return (Checksum) method.invoke(checksum);
-            } catch (ReflectiveOperationException e) {
-                throw new IllegalStateException("Could not clone checksum class " + checksum.getClass(), e);
-            }
-        } else {
-            return (Checksum) ((SdkCrc32C) checksum).clone();
-
-        }
+        super(DefaultChecksumAlgorithm.CRC32C);
     }
 }

core/sdk-core/src/main/java/software/amazon/awssdk/core/checksums/Crc32CChecksum.java

@@ -15,82 +15,24 @@
 
 package software.amazon.awssdk.core.checksums;
 
-import static software.amazon.awssdk.core.internal.util.HttpChecksumUtils.longToByte;
-
-import java.lang.reflect.Method;
-import java.util.Arrays;
-import java.util.zip.Checksum;
-import software.amazon.awssdk.annotations.SdkInternalApi;
-import software.amazon.awssdk.core.internal.checksums.factory.CrtBasedChecksumProvider;
-import software.amazon.awssdk.core.internal.checksums.factory.SdkCrc32;
+import software.amazon.awssdk.annotations.SdkProtectedApi;
+import software.amazon.awssdk.checksums.DefaultChecksumAlgorithm;
+import software.amazon.awssdk.core.internal.checksums.LegacyDelegatingChecksum;
 
 /**
  * Implementation of {@link SdkChecksum} to calculate an CRC32 checksum.
+ *
+ * <p>
+ * Implementor notes: this should've been an internal API, but we can't change it now since it's not within the internal
+ * subpackage.
+ *
  * @deprecated this class is deprecated and subject to removal.
  */
 @Deprecated
-@SdkInternalApi
-public class Crc32Checksum implements SdkChecksum {
+@SdkProtectedApi
+public class Crc32Checksum extends LegacyDelegatingChecksum {
 
-    private Checksum crc32;
-    private Checksum lastMarkedCrc32;
-    private final boolean isCrtBasedChecksum;
-
-    /**
-     * Creates CRT Based Crc32 checksum if Crt classpath for Crc32 is loaded, else create Sdk Implemented Crc32.
-     */
     public Crc32Checksum() {
-        crc32 = CrtBasedChecksumProvider.createCrc32();
-        isCrtBasedChecksum = crc32 != null;
-        if (!isCrtBasedChecksum) {
-            crc32 = SdkCrc32.create();
-        }
-    }
-
-    @Override
-    public byte[] getChecksumBytes() {
-        return Arrays.copyOfRange(longToByte(crc32.getValue()), 4, 8);
-    }
-
-    @Override
-    public void mark(int readLimit) {
-        this.lastMarkedCrc32 = cloneChecksum(crc32);
-    }
-
-    @Override
-    public void update(int b) {
-        crc32.update(b);
-    }
-
-    @Override
-    public void update(byte[] b, int off, int len) {
-        crc32.update(b, off, len);
-    }
-
-    @Override
-    public long getValue() {
-        return crc32.getValue();
-    }
-
-    @Override
-    public void reset() {
-        if ((lastMarkedCrc32 == null)) {
-            crc32.reset();
-        } else {
-            crc32 = cloneChecksum(lastMarkedCrc32);
-        }
-    }
-
-    private Checksum cloneChecksum(Checksum checksum) {
-        if (isCrtBasedChecksum) {
-            try {
-                Method method = checksum.getClass().getDeclaredMethod("clone");
-                return (Checksum) method.invoke(checksum);
-            } catch (ReflectiveOperationException e) {
-                throw new IllegalStateException("Could not clone checksum class " + checksum.getClass(), e);
-            }
-        } else {
-            return (Checksum) ((SdkCrc32) checksum).clone();
-        }
+        super(DefaultChecksumAlgorithm.CRC32);
     }
 }