Workaround for JNI DetachCurrentThread

include/belle-sip/wakelock.h

@@ -4,6 +4,7 @@
 #include <jni.h>
 #include "belle-sip/defs.h"
 
-BELLESIP_EXPORT void bellesip_wake_lock_init(JavaVM *jvm, jobject pm);
+BELLESIP_EXPORT void bellesip_wake_lock_init(JNIEnv *env, jobject pm);
+BELLESIP_EXPORT void bellesip_wake_lock_uninit(JNIEnv *env);
 
 #endif // WALE_LOCK_H

src/wakelock.c

 #include "wakelock_internal.h"
 #include "belle-sip/utils.h"
+#include <pthread.h>
 
 static JavaVM *_jvm = NULL;
 static jobject _powerManager = NULL;
+static pthread_key_t jniEnvKey;
 
-void bellesip_wake_lock_init(JavaVM *jvm, jobject pm) {
+static JNIEnv *get_jni_env(void);
+static void jni_key_cleanup(void *data);
+
+void bellesip_wake_lock_init(JNIEnv *env, jobject pm) {
 	if(_jvm == NULL) {
-		_jvm = jvm;
-		_powerManager = pm;
+		(*env)->GetJavaVM(env, &_jvm);
+		_powerManager = (*env)->NewGlobalRef(env, pm);
+		pthread_key_create(&jniEnvKey, jni_key_cleanup);
+		belle_sip_message("bellesip_wake_lock_init(): initialization succeed");
 	} else {
 		belle_sip_error("bellesip_wake_lock_init(): the wakelock system has already been initialized");
 	}
 }
 
+void bellesip_wake_lock_uninit(JNIEnv *env) {
+	_jvm = NULL;
+	if(_powerManager != NULL) {
+		(*env)->DeleteGlobalRef(env, _powerManager);
+		_powerManager = NULL;
+	}
+}
+
+static void jni_key_cleanup(void *data) {
+	belle_sip_message("Thread end. Cleanup wake lock jni environment");
+	JNIEnv *env = pthread_getspecific(jniEnvKey);
+	if(env != NULL) {
+		if(_jvm != NULL) {
+			(*_jvm)->DetachCurrentThread(_jvm);
+			pthread_setspecific(jniEnvKey, NULL);
+		} else {
+			belle_sip_fatal("Wake lock cleanup. No JVM found");
+		}
+	}
+}
+
+static JNIEnv *get_jni_env(void) {
+	JNIEnv *jenv = NULL;
+	if(_jvm != NULL) {
+		jenv = pthread_getspecific(jniEnvKey);
+		if(jenv == NULL) {
+			if((*_jvm)->AttachCurrentThread(_jvm, &jenv, NULL) == JNI_OK) {
+				pthread_setspecific(jniEnvKey, jenv);
+				belle_sip_message("get_jni_env(): thread successfuly attached");
+			} else {
+				belle_sip_fatal("get_jni_env(): thread could not be attached to the JVM");
+				jenv = NULL;
+			}
+		}
+	} else {
+		belle_sip_error("get_jni_env(): no JVM found");
+	}
+	return jenv;
+}
+
 unsigned long wake_lock_acquire(const char *tag) {
 	if(_jvm != NULL && _powerManager != NULL) {
 		JNIEnv *env;
-		if((*_jvm)->AttachCurrentThread(_jvm, &env, NULL) == JNI_OK) {
+		if(env = get_jni_env()) {
 			jclass PowerManager = (*env)->FindClass(env, "android/os/PowerManager");
-			jclass WakeLock = (*env)->FindClass(env, "android/os/PowerManager/WakeLock");
-			jint PARTIAL_WAKE_LOCK = (*env)->GetStaticIntField(
-						env, 
-						PowerManager,
-						(*env)->GetStaticFieldID(env, PowerManager, "PARTIAL_WAKE_LOCK", "I")
-						);
-			jobject lock = (*env)->CallObjectMethod(
-						env, 
-						_powerManager,
-						(*env)->GetMethodID(env, PowerManager, "newWakeLock", "(ILjava/lang/String;)Landroid/os/PowerManager/WakeLock;" ),
-						PARTIAL_WAKE_LOCK,
-						tag);
-			(*env)->CallVoidMethod(
-						env, 
-						lock,
-						(*env)->GetMethodID(env, WakeLock, "acquire", "()V"));
-			belle_sip_message("Android wake lock acquired [ref=%p]", (void *)lock);
-			(*_jvm)->DetachCurrentThread(_jvm);
-			return (unsigned long)(*env)->NewGlobalRef(env, lock);
+			jclass WakeLock = (*env)->FindClass(env, "android/os/PowerManager$WakeLock");
+
+			jfieldID fieldID = (*env)->GetStaticFieldID(env, PowerManager, "PARTIAL_WAKE_LOCK", "I");
+			jint PARTIAL_WAKE_LOCK = (*env)->GetStaticIntField(env, PowerManager, fieldID);
+
+			jstring tagString = (*env)->NewStringUTF(env, tag);
+			jmethodID newWakeLockID = (*env)->GetMethodID(env, PowerManager, "newWakeLock", "(ILjava/lang/String;)Landroid/os/PowerManager$WakeLock;");
+			jobject lock = (*env)->CallObjectMethod(env, _powerManager, newWakeLockID, PARTIAL_WAKE_LOCK, tagString);
+			(*env)->DeleteLocalRef(env, tagString);
+
+			jmethodID acquireID = (*env)->GetMethodID(env, WakeLock, "acquire", "()V");
+			(*env)->CallVoidMethod(env, lock, acquireID);
+
+			belle_sip_message("bellesip_wake_lock_acquire(): Android wake lock acquired [ref=%p]", (void *)lock);
+			lock = (*env)->NewGlobalRef(env, lock);
+			return (unsigned long)lock;
 		} else {
 			belle_sip_error("bellesip_wake_lock_acquire(): cannot attach current thread to the JVM");
 		}
 	} else {
-		belle_sip_error("bellesip_wake_lock_acquire(): cannot acquire wake lock. No jvm found");
+		belle_sip_error("bellesip_wake_lock_acquire(): cannot acquire wake lock. No JVM found");
 	}
 	return 0;
 }
@@ -53,20 +97,16 @@ void wake_lock_release(unsigned long id) {
 		if(id != 0) {
 			jobject lock = (jobject)id;
 			JNIEnv *env;
-			if((*_jvm)->AttachCurrentThread(_jvm, &env, NULL) == JNI_OK) {
-				jclass WakeLock = (*env)->FindClass(env, "android/os/PowerManager/WakeLock");
-				(*env)->CallVoidMethod(
-							env,
-							lock,
-							(*env)->GetMethodID(env, WakeLock, "release", "()V"));
-				belle_sip_message("Android wake lock released [ref=%p]", (void *)lock);
+			if(env = get_jni_env()) {
+				jclass WakeLock = (*env)->FindClass(env, "android/os/PowerManager$WakeLock");
+				(*env)->CallVoidMethod(env, lock, (*env)->GetMethodID(env, WakeLock, "release", "()V"));
+				belle_sip_message("wake_lock_release(): Android wake lock released [ref=%p]", (void *)lock);
 				(*env)->DeleteGlobalRef(env, lock);
-				(*_jvm)->DetachCurrentThread(_jvm);
 			} else {
 				belle_sip_error("bellesip_wake_lock_release(): cannot attach current thread to the JVM");
 			}
 		}
 	} else {
-		belle_sip_error("wake_lock_release(): cannot release wake lock. No jvm found");
+		belle_sip_error("wake_lock_release(): cannot release wake lock. No JVM found");
 	}
 }