Java: extend JniWrapperCache checks to identify double dispose problem

This change extends debug checks in JniWrapperCache class
to show the problem related to double dispose.

When we remove an entry from JniWrapperCache in 'get_cached_wrapper_impl()'
because the reference was invalidated we must anticipate, that the cleanup
will be scheduled for this non-existent object. It may cause problems, because
the cleanup of weak reference entry for the old object may remove the entry
for the new entry.

This commit extends checking and again makes 'stressTestJniWeakReferenceCache()'
test to fail.

In next commit the fix will be implemented to prevent such double-dispose.

Signed-off-by: Patryk Wrobel <[email protected]>

functional-tests/functional/android/src/test/java/com/here/android/RobolectricApplication.java

@@ -50,6 +50,7 @@ public void onCreate() {
     if (isFirstTime) {
       isFirstTime = false; // Only load libraries once
       loadNativeLibraries();
+      NativeBase.propagateCleanupException = true;
       Runtime.getRuntime()
           .addShutdownHook(
               new Thread() {

gluecodium/src/main/resources/templates/java/NativeBase.mustache

@@ -76,6 +76,8 @@ public abstract class NativeBase {
   private static final Set<Reference<?>> REFERENCES =
       Collections.newSetFromMap(new ConcurrentHashMap<Reference<?>, Boolean>());
 
+  public static boolean propagateCleanupException = false;
+
   private static final ReferenceQueue<NativeBase> REFERENCE_QUEUE = new ReferenceQueue<>();
   private final long nativeHandle;
 
@@ -126,6 +128,9 @@ public abstract class NativeBase {
         ((DisposableReference) reference).dispose();
       } catch (Throwable t) {
         LOGGER.log(Level.SEVERE, "Error cleaning up after reference.", t);
+        if (propagateCleanupException) {
+            throw t;
+        }
       }
     }
   }

gluecodium/src/main/resources/templates/jni/utils/JniWrapperCacheImplementation.mustache

@@ -74,6 +74,13 @@ void JniWrapperCache::remove_cached_wrapper_impl(JNIEnv* jenv, const void* obj_p
     std::lock_guard<std::mutex> lock(s_mutex);
 
     auto iter = s_wrapper_cache.find(obj_ptr);
+
+#ifdef INTERNAL_GLUECODIUM_JNI_WEAK_REF_CHECK
+    if (iter == s_wrapper_cache.end()) {
+        jenv->ThrowNew(jenv->FindClass("java/lang/Exception"), "Invalid removal of cache entry");
+    }
+#endif
+
     if (iter != s_wrapper_cache.end()) {
         jenv->DeleteWeakGlobalRef(iter->second);
         s_wrapper_cache.erase(iter);

gluecodium/src/test/resources/smoke/namespace_basic/output/android/com/example/foo/bar/NativeBase.java

@@ -56,6 +56,8 @@ public abstract class NativeBase {
   private static final Set<Reference<?>> REFERENCES =
       Collections.newSetFromMap(new ConcurrentHashMap<Reference<?>, Boolean>());
 
+  public static boolean propagateCleanupException = false;
+
   private static final ReferenceQueue<NativeBase> REFERENCE_QUEUE = new ReferenceQueue<>();
   private final long nativeHandle;
 
@@ -106,6 +108,9 @@ private static void cleanUpQueue() {
         ((DisposableReference) reference).dispose();
       } catch (Throwable t) {
         LOGGER.log(Level.SEVERE, "Error cleaning up after reference.", t);
+        if (propagateCleanupException) {
+            throw t;
+        }
       }
     }
   }