virtualx-engine/platform/android/thread_jandroid.cpp

/*************************************************************************/
/*  thread_jandroid.cpp                                                  */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
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/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur.                 */
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#include "thread_jandroid.h"

#include <android/log.h>

#include "core/os/thread.h"

static JavaVM *java_vm = nullptr;
static thread_local JNIEnv *env = nullptr;

// The logic here need to improve, init_thread/term_tread are designed to work with Thread::callback
// Calling init_thread from setup_android_thread and get_jni_env to setup an env we're keeping and not detaching
// could cause issues on app termination.
//
// We should be making sure that any thread started calls a nice cleanup function when it's done,
// especially now that we use many more threads.

static void init_thread() {
	if (env) {
		// thread never detached! just keep using...
		return;
	}

	java_vm->AttachCurrentThread(&env, nullptr);
}

static void term_thread() {
	java_vm->DetachCurrentThread();

	// this is no longer valid, must called init_thread to re-establish
	env = nullptr;
}

void init_thread_jandroid(JavaVM *p_jvm, JNIEnv *p_env) {
	java_vm = p_jvm;
	env = p_env;
	Thread::_set_platform_funcs(nullptr, nullptr, &init_thread, &term_thread);
}

void setup_android_thread() {
	if (!env) {
		// !BAS! see remarks above
		init_thread();
	}
}

JNIEnv *get_jni_env() {
	if (!env) {
		// !BAS! see remarks above
		init_thread();
	}

	return env;
}