fix eclipse-aspectj#285

1.write SAME_BYTES to cacheMap when wovenbytes is null
2.fix TODO in SimpleCache#getAndInitialize, use Optional to help indicating case in which Hit cache but need to return null

Signed-off-by: KimmingLau <[email protected]>

Author: KimmingLau

loadtime/src/main/java/org/aspectj/weaver/loadtime/Aj.java

@@ -20,6 +20,7 @@
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Optional;
 import java.util.Set;
 import java.util.StringTokenizer;
 
@@ -104,9 +105,9 @@ public byte[] preProcess(String className, final byte[] bytes, ClassLoader class
 			synchronized (classLoader) {
 
 				if (SimpleCacheFactory.isEnabled()) {
-					byte[] cacheBytes= laCache.getAndInitialize(className, bytes, classLoader, protectionDomain);
-					if (cacheBytes!=null){
-							return cacheBytes;
+					Optional<byte[]> cacheBytes = laCache.getAndInitialize(className, bytes, classLoader, protectionDomain);
+					if (cacheBytes != null){
+						return cacheBytes.orElse(null);
 					}
 				}
 

weaver/src/main/java/org/aspectj/weaver/tools/cache/SimpleCache.java

@@ -15,6 +15,7 @@
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.Optional;
 import java.util.zip.CRC32;
 
 import org.aspectj.weaver.Dump;
@@ -64,23 +65,20 @@ protected SimpleCache(String folder, boolean enabled) {
 		}
 	}
 
-	public byte[] getAndInitialize(String classname, byte[] bytes,
+	public Optional<byte[]> getAndInitialize(String classname, byte[] bytes,
 			ClassLoader loader, ProtectionDomain protectionDomain) {
 		if (!enabled) {
 			return null;
 		}
 		byte[] res = get(classname, bytes);
 
 		if (Arrays.equals(SAME_BYTES, res)) {
-			// TODO: Should we return null (means "not transformed") in this case?
-			return bytes;
-		} else {
-			if (res != null) {
-				initializeClass(classname, res, loader, protectionDomain);
-			}
-			return res;
+			return Optional.empty();
+		} else if (res != null) {
+			initializeClass(classname, res, loader, protectionDomain);
+			return Optional.of(res);
 		}
-
+		return null;
 	}
 
 	private byte[] get(String classname, byte bytes[]) {
@@ -97,7 +95,7 @@ public void put(String classname, byte[] origbytes, byte[] wovenbytes) {
 
 		String key = generateKey(classname, origbytes);
 
-		if (Arrays.equals(origbytes, wovenbytes)) {
+		if (wovenbytes == null || Arrays.equals(origbytes, wovenbytes)) {
 			cacheMap.put(key, SAME_BYTES);
 			return;
 		}