From a50671dfe8e8b947ac7016edf3dc92c6ecf0fa94 Mon Sep 17 00:00:00 2001
From: Stefan Bratanov <stefan.bratanov93@gmail.com>
Date: Wed, 23 Nov 2022 20:24:48 +0000
Subject: [PATCH] handle exceptions

---
 bindings/java/c_kzg_4844_jni.c | 45 ++++++++++++++++++++++++++++++----
 1 file changed, 40 insertions(+), 5 deletions(-)

diff --git a/bindings/java/c_kzg_4844_jni.c b/bindings/java/c_kzg_4844_jni.c
index 5da81ba..5d9f8cf 100644
--- a/bindings/java/c_kzg_4844_jni.c
+++ b/bindings/java/c_kzg_4844_jni.c
@@ -1,9 +1,33 @@
+#include <stdio.h>
 #include <stdlib.h>
 #include "c_kzg_4844_jni.h"
 #include "c_kzg_4844.h"
 
+static const char *C_KZG_RETURN_TYPES[] = {
+    "C_KZG_OK", "C_KZG_BADARGS", "C_KZG_ERROR", "C_KZG_MALLOC"};
+
 KZGSettings *settings;
 
+void reset_trusted_setup()
+{
+  free(settings);
+  settings = NULL;
+}
+
+void throw_exception(JNIEnv *env, const char *message)
+{
+  jclass Exception = (*env)->FindClass(env, "java/lang/RuntimeException");
+  (*env)->ThrowNew(env, Exception, message);
+}
+
+void verify_trusted_setup_is_loaded(JNIEnv *env)
+{
+  if (settings == NULL)
+  {
+    throw_exception(env, "Trusted Setup is not loaded.");
+  }
+}
+
 JNIEXPORT void JNICALL Java_CKzg4844JNI_loadTrustedSetup(JNIEnv *env, jclass thisCls, jstring file)
 {
   settings = malloc(sizeof(KZGSettings));
@@ -14,16 +38,22 @@ JNIEXPORT void JNICALL Java_CKzg4844JNI_loadTrustedSetup(JNIEnv *env, jclass thi
 
   if (f == NULL)
   {
-    free(settings);
+    reset_trusted_setup();
     (*env)->ReleaseStringUTFChars(env, file, file_native);
+    throw_exception(env, "Couldn't load Trusted Setup. File might not exist or there is a permission issue.");
     return;
   }
 
-  if (load_trusted_setup(settings, f) != C_KZG_OK)
+  C_KZG_RET ret = load_trusted_setup(settings, f);
+
+  if (ret != C_KZG_OK)
   {
-    free(settings);
-    fclose(f);
+    reset_trusted_setup();
     (*env)->ReleaseStringUTFChars(env, file, file_native);
+    fclose(f);
+    char arr[60];
+    sprintf(arr, "There was an error while loading the Trusted Setup: %s", C_KZG_RETURN_TYPES[ret]);
+    throw_exception(env, arr);
     return;
   }
 
@@ -36,13 +66,15 @@ JNIEXPORT void JNICALL Java_CKzg4844JNI_loadTrustedSetup(JNIEnv *env, jclass thi
 
 JNIEXPORT void JNICALL Java_CKzg4844JNI_freeTrustedSetup(JNIEnv *env, jclass thisCls)
 {
+  verify_trusted_setup_is_loaded(env);
   free_trusted_setup(settings);
-  free(settings);
+  reset_trusted_setup();
   printf("Trusted Setup was unloaded\n");
 }
 
 JNIEXPORT jbyteArray JNICALL Java_CKzg4844JNI_computeAggregateKzgProof(JNIEnv *env, jclass thisCls, jbyteArray blobs, jint count)
 {
+  verify_trusted_setup_is_loaded(env);
   // NOT YET IMPLEMENTED
   // jbyte *blobs_native = (*env)->GetByteArrayElements(env, blobs, NULL);
   jbyteArray proof = (*env)->NewByteArray(env, 48);
@@ -51,12 +83,14 @@ JNIEXPORT jbyteArray JNICALL Java_CKzg4844JNI_computeAggregateKzgProof(JNIEnv *e
 
 JNIEXPORT jboolean JNICALL Java_CKzg4844JNI_verifyAggregateKzgProof(JNIEnv *env, jclass thisCls, jbyteArray blobs, jbyteArray commitments, jint count, jbyteArray proof)
 {
+  verify_trusted_setup_is_loaded(env);
   // NOT YET IMPLEMENTED
   return false;
 }
 
 JNIEXPORT jbyteArray JNICALL Java_CKzg4844JNI_blobToKzgCommitment(JNIEnv *env, jclass thisCls, jbyteArray blob)
 {
+  verify_trusted_setup_is_loaded(env);
   // NOT YET IMPLEMENTED
   jbyteArray ret = (*env)->NewByteArray(env, 48);
   return ret;
@@ -64,6 +98,7 @@ JNIEXPORT jbyteArray JNICALL Java_CKzg4844JNI_blobToKzgCommitment(JNIEnv *env, j
 
 JNIEXPORT jboolean JNICALL Java_CKzg4844JNI_verifyKzgProof(JNIEnv *env, jclass thisCls, jbyteArray commitment, jbyteArray z, jbyteArray y, jbyteArray proof)
 {
+  verify_trusted_setup_is_loaded(env);
   // NOT YET IMPLEMENTED
   return false;
 }