From c5de9439054c9bc3112b8f93dfea9e477c5ccdb5 Mon Sep 17 00:00:00 2001
From: MohitMaliFtechiz <futuretechnoworld.mohit@gmail.com>
Date: Mon, 27 Jan 2025 16:14:36 +0530
Subject: [PATCH] Fixed the native crash happening on Android.

* Improved the `getPtr` method to throw a `NativeHandleDisposedException` when a native object is `nullptr`, updated the `CATCH_EXCEPTION` macro to handle this exception by mapping it to `java.lang.IllegalStateException`, and ensured proper error handling to prevent crashes when accessing disposed objects.
---
 lib/src/main/cpp/macros.h | 3 +++
 lib/src/main/cpp/utils.h  | 8 ++++++++
 2 files changed, 11 insertions(+)

diff --git a/lib/src/main/cpp/macros.h b/lib/src/main/cpp/macros.h
index 46201d5..5a31e51 100644
--- a/lib/src/main/cpp/macros.h
+++ b/lib/src/main/cpp/macros.h
@@ -53,6 +53,9 @@ catch(const zim::ZimFileFormatError& e) { \
 } catch(const zim::EntryNotFound& e) { \
   throwException(env, "org/kiwix/libzim/EntryNotFoundException", e.what()); \
   return RET; \
+} catch (const NativeHandleDisposedException& e) { \
+  throwException(env, "java/lang/IllegalStateException", e.what()); \
+  return RET; \
 } catch (const std::ios_base::failure& e) { \
   throwException(env, "java/io/IOException", e.what()); \
   return RET; \
diff --git a/lib/src/main/cpp/utils.h b/lib/src/main/cpp/utils.h
index 9324adf..c5d7d12 100644
--- a/lib/src/main/cpp/utils.h
+++ b/lib/src/main/cpp/utils.h
@@ -96,6 +96,11 @@ inline void setHandle(JNIEnv* env, jobject thisObj, Args && ...args)
 }
 #define SET_HANDLE(NATIVE_TYPE, OBJ, VALUE) setHandle<NATIVE_TYPE>(env, OBJ, VALUE)
 
+class NativeHandleDisposedException : public std::runtime_error {
+public:
+    explicit NativeHandleDisposedException(const std::string& message)
+            : std::runtime_error(message) {}
+};
 
 // Return a shared_ptr for the handle
 template<typename T>
@@ -104,6 +109,9 @@ shared_ptr<T> getPtr(JNIEnv* env, jobject thisObj, const char* handleName = "nat
   jclass thisClass = env->GetObjectClass(thisObj);
   jfieldID fidNumber = env->GetFieldID(thisClass, handleName, "J");
   auto handle = reinterpret_cast<shared_ptr<T>*>(env->GetLongField(thisObj, fidNumber));
+  if (handle == nullptr) {
+      throw NativeHandleDisposedException("The native object is already has been disposed");
+  }
   return *handle;
 }
 #define GET_PTR(NATIVE_TYPE) getPtr<NATIVE_TYPE>(env, thisObj)