Ensure native create methods do not return zero (without throwing); somewhat paranoia, but also covers corner cases in which exception are canceled e.g. by DbExceptionListener

Author: greenrobot

objectbox-java/src/main/java/io/objectbox/BoxStore.java

@@ -227,6 +227,8 @@ public static boolean isObjectBrowserAvailable() {
 
         try {
             handle = nativeCreateWithFlatOptions(builder.buildFlatStoreOptions(canonicalPath), builder.model);
+            if(handle == 0) throw new DbException("Could not create native store");
+
             int debugFlags = builder.debugFlags;
             if (debugFlags != 0) {
                 debugTxRead = (debugFlags & DebugFlags.LOG_TRANSACTIONS_READ) != 0;
@@ -426,6 +428,8 @@ public Transaction beginTx() {
             System.out.println("Begin TX with commit count " + initialCommitCount);
         }
         long nativeTx = nativeBeginTx(handle);
+        if(nativeTx == 0) throw new DbException("Could not create native transaction");
+
         Transaction tx = new Transaction(this, nativeTx, initialCommitCount);
         synchronized (transactions) {
             transactions.add(tx);
@@ -450,6 +454,8 @@ public Transaction beginReadTx() {
             System.out.println("Begin read TX with commit count " + initialCommitCount);
         }
         long nativeTx = nativeBeginReadTx(handle);
+        if(nativeTx == 0) throw new DbException("Could not create native read transaction");
+
         Transaction tx = new Transaction(this, nativeTx, initialCommitCount);
         synchronized (transactions) {
             transactions.add(tx);

objectbox-java/src/main/java/io/objectbox/Transaction.java

@@ -22,6 +22,7 @@
 
 import io.objectbox.annotation.apihint.Experimental;
 import io.objectbox.annotation.apihint.Internal;
+import io.objectbox.exception.DbException;
 import io.objectbox.internal.CursorFactory;
 
 @Internal
@@ -183,6 +184,7 @@ public <T> Cursor<T> createCursor(Class<T> entityClass) {
         EntityInfo<T> entityInfo = store.getEntityInfo(entityClass);
         CursorFactory<T> factory = entityInfo.getCursorFactory();
         long cursorHandle = nativeCreateCursor(transaction, entityInfo.getDbName(), entityClass);
+        if(cursorHandle == 0) throw new DbException("Could not create native cursor");
         return factory.createCursor(this, cursorHandle, store);
     }
 

objectbox-java/src/main/java/io/objectbox/internal/DebugCursor.java

@@ -21,6 +21,7 @@
 import io.objectbox.InternalAccess;
 import io.objectbox.Transaction;
 import io.objectbox.annotation.apihint.Beta;
+import io.objectbox.exception.DbException;
 
 /** Not intended for normal use. */
 @Beta
@@ -40,7 +41,9 @@ public class DebugCursor implements Closeable {
 
     public static DebugCursor create(Transaction tx) {
         long txHandle = InternalAccess.getHandle(tx);
-        return new DebugCursor(tx, nativeCreate(txHandle));
+        long handle = nativeCreate(txHandle);
+        if(handle == 0) throw new DbException("Could not create native debug cursor");
+        return new DebugCursor(tx, handle);
     }
 
     public DebugCursor(Transaction tx, long handle) {

objectbox-java/src/main/java/io/objectbox/query/QueryBuilder.java

@@ -29,6 +29,7 @@
 import io.objectbox.Property;
 import io.objectbox.annotation.apihint.Experimental;
 import io.objectbox.annotation.apihint.Internal;
+import io.objectbox.exception.DbException;
 import io.objectbox.relation.RelationInfo;
 
 /**
@@ -191,6 +192,7 @@ public QueryBuilder(Box<T> box, long storeHandle, String entityName) {
         this.box = box;
         this.storeHandle = storeHandle;
         handle = nativeCreate(storeHandle, entityName);
+        if(handle == 0) throw new DbException("Could not create native query builder");
         isSubQuery = false;
     }
 
@@ -232,6 +234,7 @@ public Query<T> build() {
             throw new IllegalStateException("Incomplete logic condition. Use or()/and() between two conditions only.");
         }
         long queryHandle = nativeBuild(handle);
+        if(queryHandle == 0) throw new DbException("Could not create native query");
         Query<T> query = new Query<>(box, queryHandle, eagerRelations, filter, comparator);
         close();
         return query;