Merge pull request #332 from AngelAuraMC/feat/export-javavm-pointer

qol for modders

app_pojavlauncher/src/main/java/net/kdt/pojavlaunch/Tools.java

@@ -1943,4 +1943,6 @@ public final class Tools {
          */
         public static native void initializeControllerSubsystems();
     }
+    public static native String jObjectToString(Object object);
+    public static native long getJavaVMPointer();
 }

app_pojavlauncher/src/main/java/net/kdt/pojavlaunch/utils/JREUtils.java

@@ -267,6 +267,9 @@ public class JREUtils {
             envMap.put("POJAV_LOAD_TURNIP", "1");
         }
 
+        envMap.put("DALVIK_APPLICATION", Tools.jObjectToString(activity.getApplication()));
+        envMap.put("DALVIK_JAVAVM", String.valueOf(Tools.getJavaVMPointer()));
+
         readCustomEnv(envMap); // Must be last so it overrides anything the user sets for obvious reasons.
 
         for (Map.Entry<String, String> env : envMap.entrySet()) {

app_pojavlauncher/src/main/jni/utils.c

@@ -200,3 +200,30 @@ JNIEXPORT jint JNICALL Java_net_kdt_pojavlaunch_utils_JREUtils_executeForkedBina
 }
 */
 
+// WARNING: This does not release the global ref, this can be a memory leak
+JNIEXPORT jstring JNICALL
+Java_net_kdt_pojavlaunch_Tools_jObjectToString(JNIEnv *env, jclass clazz, jobject object) {
+    if (object == NULL) {
+        return NULL;
+    }
+
+    jobject globalRef = (*env)->NewGlobalRef(env, object);
+    if (globalRef == NULL) {
+        return NULL;
+    }
+
+    char buf[32];
+    snprintf(buf, sizeof(buf), "%p", globalRef);
+
+    return (*env)->NewStringUTF(env, buf);
+}
+
+JNIEXPORT jlong JNICALL
+Java_net_kdt_pojavlaunch_Tools_getJavaVMPointer(JNIEnv *env, jclass clazz) {
+	JavaVM *vm;
+	if ((*env)->GetJavaVM(env, &vm) != JNI_OK) {
+		return -1;
+	}
+
+	return (jlong)(uintptr_t)vm;
+}