[DotNet] Attach current thread to MonoVM when registering a type

src/monodroid/jni/monodroid-glue.cc

@@ -2537,6 +2537,8 @@ MonodroidRuntime::Java_mono_android_Runtime_register (JNIEnv *env, jstring manag
 
  utils.monodroid_runtime_invoke (domain, register_jni_natives, nullptr, args, nullptr);
 #else // ndef NET
+// mono_jit_thread_attach (nullptr); // There's just one domain in .net
+
 #if !defined (ANDROID)
  mono_runtime_invoke (register_jni_natives, nullptr, args, nullptr);
 #else

tests/Mono.Android-Tests/Java.Interop/JnienvTest.cs

@@ -32,11 +32,22 @@ public void TestMyPaintColor ()
  }
  }
 
+ [DllImport ("reuse-threads")]
+ static extern int rt_register_type_on_new_thread (string java_type_namem, IntPtr class_loader);
+
  delegate void CB (IntPtr jnienv, IntPtr java_instance);
 
  [DllImport ("reuse-threads")]
  static extern int rt_invoke_callback_on_new_thread (CB cb);
 
+ [Test]
+ public void RegisterTypeOnNewThread ()
+ {
+ Java.Lang.JavaSystem.LoadLibrary ("reuse-threads");
+ int ret = rt_register_type_on_new_thread ("from.NewThread", Application.Context.ClassLoader.Handle);
+ Assert.AreEqual (0, ret, $"Java type registration on a new thread failed with code {ret}");
+ }
+
  [Test]
  public void ThreadReuse ()
  {
@@ -434,6 +445,10 @@ public void DoNotLeakWeakReferences ()
  }
  }
 
+ [Register ("from/NewThread")]
+ class RegisterMeOnNewThread : Java.Lang.Object
+ {}
+
  class MyCb : Java.Lang.Object, Java.Lang.IRunnable {
  public void Run ()
  {

tests/Mono.Android-Tests/jni/reuse-threads.c

@@ -81,6 +81,12 @@
 #include <android/log.h>
 #include <jni.h>
 
+typedef struct
+{
+ const char *java_type_name;
+ jobject class_loader;
+} RegisterFromThreadContext;
+
 typedef void (*CB)(JNIEnv *env, jobject self);
 
 static JavaVM *gvm;
@@ -113,9 +119,9 @@ _get_env (const char *where)
 }
 
 static jobject
-_create_java_instance (JNIEnv *env)
+_create_java_instance (JNIEnv *env, const char *class_name)
 {
- jclass Object_class = (*env)->FindClass (env, "java/lang/Object");
+ jclass Object_class = (*env)->FindClass (env, class_name);
  jmethodID Object_ctor = (*env)->GetMethodID (env, Object_class, "<init>", "()V");
 
  jobject instance = (*env)->NewObject (env, Object_class, Object_ctor);
@@ -154,7 +160,7 @@ _call_cb_from_new_thread (void *cb)
  }
 
  /* 5: Execution of T enters managed code... */
- jobject instance = _create_java_instance (env);
+ jobject instance = _create_java_instance (env, "java/lang/Object");
  _cb (env, instance);
 
  return NULL;
@@ -200,3 +206,115 @@ rt_invoke_callback_on_new_thread (CB cb)
  return 0;
 }
 
+/* We return -2 for errors, because -1 is reserved for the pthreads PTHREAD_CANCELED special value, indicating that the
+ * thread was canceled. */
+static int
+_register_type_from_new_thread (void *data)
+{
+ RegisterFromThreadContext *context = (RegisterFromThreadContext*)data;
+
+ if (context == NULL) {
+ return -100;
+ }
+
+ JNIEnv *env = _get_env ("_register_type_from_new_thread");
+
+ if ((*env)->PushLocalFrame (env, 3) < 0) {
+ __android_log_print (ANDROID_LOG_INFO, "XA/RuntimeTest", "FAILURE: unable to create a local reference frame!");
+
+ if ((*env)->ExceptionOccurred (env)) {
+ (*env)->ExceptionClear (env);
+ (*env)->ExceptionDescribe (env);
+ }
+
+ return -101;
+ }
+
+ int ret = 0;
+ jclass ClassLoader_class = (*env)->FindClass (env, "java/lang/ClassLoader");
+ if (ClassLoader_class == NULL) {
+ ret = -102;
+ __android_log_print (ANDROID_LOG_INFO, "XA/RuntimeTest", "FAILURE: unable to find the 'java/lang/ClassLoader' class!");
+ goto cleanup;
+ }
+
+ jmethodID loadClass = (*env)->GetMethodID (env, ClassLoader_class, "loadClass", "(Ljava/lang/String;)Ljava/lang/Class;");
+ if (loadClass == NULL) {
+ ret = -103;
+ __android_log_print (ANDROID_LOG_INFO, "XA/RuntimeTest", "FAILURE: unable to get id of method 'loadClass' in the 'java/lang/ClassLoader' class!");
+ goto cleanup;
+ }
+
+ jobject loaded_class = (*env)->CallObjectMethod (env, context->class_loader, loadClass, context->java_type_name);
+
+ if ((*env)->ExceptionOccurred (env) != NULL) {
+ (*env)->ExceptionClear (env);
+ __android_log_print (ANDROID_LOG_INFO, "XA/RuntimeTest", "FAILURE: class '%s' cannot be loaded, Java exception thrown!", context->java_type_name);
+ (*env)->ExceptionDescribe (env);
+ ret = -104;
+ goto cleanup;
+ }
+
+ if (loaded_class == NULL) {
+ ret = -105;
+ __android_log_print (ANDROID_LOG_INFO, "XA/RuntimeTest", "FAILURE: 'java/lang/ClassLoader' wasn't able to load the '%s' class!", context->java_type_name);
+ goto cleanup;
+ }
+
+ jmethodID Object_ctor = (*env)->GetMethodID (env, loaded_class, "<init>", "()V");
+ if (Object_ctor == NULL) {
+ ret = -106;
+ __android_log_print (ANDROID_LOG_INFO, "XA/RuntimeTest", "FAILURE: unable to find the '%s' class constructor!", context->java_type_name);
+ goto cleanup;
+ }
+
+ jobject instance = (*env)->NewObject (env, loaded_class, Object_ctor);
+
+ if ((*env)->ExceptionOccurred (env) != NULL || instance == NULL) {
+ (*env)->ExceptionClear (env);
+ __android_log_print (ANDROID_LOG_INFO, "XA/RuntimeTest", "FAILURE: instance of class '%s' wasn't created!", context->java_type_name);
+ (*env)->ExceptionDescribe (env);
+ ret = -107;
+ }
+
+ if (instance == NULL) {
+ ret = -108;
+ __android_log_print (ANDROID_LOG_INFO, "XA/RuntimeTest", "FAILURE: unable to create instance of the '%s' class!", context->java_type_name);
+ }
+
+ cleanup:
+ (*env)->PopLocalFrame (env, NULL);
+
+ return ret;
+}
+
+JNIEXPORT int JNICALL
+rt_register_type_on_new_thread (const char *java_type_name, jobject class_loader)
+{
+ JNIEnv *env = _get_env ("rt_register_type_on_new_thread");
+ pthread_t t;
+ RegisterFromThreadContext context = {
+ java_type_name,
+ class_loader,
+ };
+
+ int r = pthread_create (&t, NULL, _register_type_from_new_thread, &context);
+
+ if (r) {
+ __android_log_print (ANDROID_LOG_INFO, "XA/RuntimeTest", "RegisterOnNewThread: pthread_create() failed! %i: %s", r, strerror (r));
+ return -200;
+ }
+
+ void *tr;
+ if (pthread_join (t, &tr) != 0) {
+ __android_log_print (ANDROID_LOG_INFO, "XA/RuntimeTest", "RegisterOnNewThread: pthread_join() failed! %i: %s", r, strerror (r));
+ return -201;
+ }
+
+ if ((int)tr == -1 /* PTHREAD_CANCELED - not defined in bionic */) {
+ __android_log_print (ANDROID_LOG_INFO, "XA/RuntimeTest", "RegisterOnNewThread: worker thread was canceled");
+ return -202;
+ }
+
+ return (int)tr;
+}