From 8a6d23a06fc03209d17390ade9ec6043f6716aac Mon Sep 17 00:00:00 2001
From: khanhduytran0 <khanhduytran032@gmail.com>
Date: Wed, 9 Sep 2020 06:09:50 +0700
Subject: [PATCH] JNI: Attach Android thread to JRE, is it safe?

---
 app/src/main/jni/egl_bridge.c   | 2 +-
 app/src/main/jni/input_bridge.c | 7 ++++++-
 app/src/main/jni/jre_launcher.c | 2 +-
 app/src/main/jni/utils.h        | 5 ++++-
 4 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/app/src/main/jni/egl_bridge.c b/app/src/main/jni/egl_bridge.c
index a0bcf3eeb..b8a48faaf 100644
--- a/app/src/main/jni/egl_bridge.c
+++ b/app/src/main/jni/egl_bridge.c
@@ -154,7 +154,7 @@ JNIEXPORT jboolean JNICALL Java_org_lwjgl_glfw_GLFW_nativeEglMakeCurrent(JNIEnv*
 	printf("First frame error: %p\n", eglGetError());
 #endif
 
-    isEglMakeCurrentCalled = 1;
+    isInputReady = true;
 
 	return success == EGL_TRUE ? JNI_TRUE : JNI_FALSE;
 }
diff --git a/app/src/main/jni/input_bridge.c b/app/src/main/jni/input_bridge.c
index d6b4b781d..28c1bbfed 100644
--- a/app/src/main/jni/input_bridge.c
+++ b/app/src/main/jni/input_bridge.c
@@ -3,7 +3,12 @@
 #include "utils.h"
 
 JNIEXPORT void JNICALL Java_net_kdt_pojavlaunch_LWJGLInputSender_sendDataToJRE(JNIEnv* env, jclass clazz, jint type, jstring data) {
-	if (isEglMakeCurrentCalled == 1) {
+	if (isInputReady) {
+        if (!isAndroidThreadAttached) {
+            (*runtimeJavaVMPtr)->AttachCurrentThread(runtimeJavaVMPtr, &runtimeJNIEnvPtr, NULL);
+            isAndroidThreadAttached = true;
+        }
+        
         // Convert Dalvik string to JRE string: should or use directly?
         char *data_c = (char*)(*env)->GetStringUTFChars(env, data, 0);
         jstring data_jre = (*runtimeJNIEnvPtr)->NewStringUTF(runtimeJNIEnvPtr, data_c);
diff --git a/app/src/main/jni/jre_launcher.c b/app/src/main/jni/jre_launcher.c
index e92fb38fe..4cbd54f35 100644
--- a/app/src/main/jni/jre_launcher.c
+++ b/app/src/main/jni/jre_launcher.c
@@ -68,7 +68,7 @@ jint JNI_OnLoad(JavaVM* vm, void* reserved)
 */
 	} else if (dalvikJavaVMPtr != vm) {
 		runtimeJavaVMPtr = vm;
-		(*vm)->GetEnv(vm, (void**) &runtimeJNIEnvPtr, JNI_VERSION_1_4);
+		// (*vm)->GetEnv(vm, (void**) &runtimeJNIEnvPtr, JNI_VERSION_1_4);
 	}
 	LOGD("JNI_OnLoad returning()");
     return JNI_VERSION_1_4;
diff --git a/app/src/main/jni/utils.h b/app/src/main/jni/utils.h
index 4682d2777..202b0a607 100644
--- a/app/src/main/jni/utils.h
+++ b/app/src/main/jni/utils.h
@@ -1,13 +1,16 @@
 #ifndef _BINARY_UTILS_H_
 #define _BINARY_UTILS_H_
 
+#include <stdbool.h>
+
 JavaVM *runtimeJavaVMPtr;
 JNIEnv *runtimeJNIEnvPtr;
 
 JavaVM *dalvikJavaVMPtr;
 JNIEnv *dalvikJNIEnvPtr;
 
-int isEglMakeCurrentCalled;
+bool isInputReady;
+bool isAndroidThreadAttached;
 
 char** convert_to_char_array(JNIEnv *env, jobjectArray jstringArray);
 jobjectArray convert_from_char_array(JNIEnv *env, char **charArray, int num_rows);