[android][firestore] implement Document and Query snapshot serialize async tasks

android/src/main/java/io/invertase/firebase/firestore/DocumentSnapshotSerializeAsyncTask.java

@@ -0,0 +1,47 @@
+package io.invertase.firebase.firestore;
+
+import android.os.AsyncTask;
+
+import com.facebook.react.bridge.ReactContext;
+import com.facebook.react.bridge.WritableMap;
+import com.google.firebase.firestore.DocumentSnapshot;
+
+import java.lang.ref.WeakReference;
+
+class DocumentSnapshotSerializeAsyncTask extends AsyncTask<Object, Void, WritableMap> {
+  private WeakReference<ReactContext> reactContextWeakReference;
+  private WeakReference<RNFirebaseFirestoreDocumentReference> referenceWeakReference;
+
+  DocumentSnapshotSerializeAsyncTask(
+    ReactContext context,
+    RNFirebaseFirestoreDocumentReference reference
+  ) {
+    referenceWeakReference = new WeakReference<>(reference);
+    reactContextWeakReference = new WeakReference<>(context);
+  }
+
+  @Override
+  protected final WritableMap doInBackground(Object... params) {
+    DocumentSnapshot querySnapshot = (DocumentSnapshot) params[0];
+
+    try {
+      return FirestoreSerialize.snapshotToWritableMap(querySnapshot);
+    } catch (RuntimeException e) {
+      if (isAvailable()) {
+        reactContextWeakReference.get().handleException(e);
+      } else {
+        throw e;
+      }
+      return null;
+    }
+  }
+
+  @Override
+  protected void onPostExecute(WritableMap writableMap) {
+    // do nothing as overridden on usage
+  }
+
+  private Boolean isAvailable() {
+    return reactContextWeakReference.get() != null && referenceWeakReference.get() != null;
+  }
+}

android/src/main/java/io/invertase/firebase/firestore/QuerySnapshotSerializeAsyncTask.java

@@ -0,0 +1,47 @@
+package io.invertase.firebase.firestore;
+
+import android.os.AsyncTask;
+
+import com.facebook.react.bridge.ReactContext;
+import com.facebook.react.bridge.WritableMap;
+import com.google.firebase.firestore.QuerySnapshot;
+
+import java.lang.ref.WeakReference;
+
+class QuerySnapshotSerializeAsyncTask extends AsyncTask<Object, Void, WritableMap> {
+  private WeakReference<ReactContext> reactContextWeakReference;
+  private WeakReference<RNFirebaseFirestoreCollectionReference> referenceWeakReference;
+
+  QuerySnapshotSerializeAsyncTask(
+    ReactContext context,
+    RNFirebaseFirestoreCollectionReference reference
+  ) {
+    referenceWeakReference = new WeakReference<>(reference);
+    reactContextWeakReference = new WeakReference<>(context);
+  }
+
+  @Override
+  protected final WritableMap doInBackground(Object... params) {
+    QuerySnapshot querySnapshot = (QuerySnapshot) params[0];
+
+    try {
+      return FirestoreSerialize.snapshotToWritableMap(querySnapshot);
+    } catch (RuntimeException e) {
+      if (isAvailable()) {
+        reactContextWeakReference.get().handleException(e);
+      } else {
+        throw e;
+      }
+      return null;
+    }
+  }
+
+  @Override
+  protected void onPostExecute(WritableMap writableMap) {
+    // do nothing as overridden on usage
+  }
+
+  private Boolean isAvailable() {
+    return reactContextWeakReference.get() != null && referenceWeakReference.get() != null;
+  }
+}