HONEYCOMB-10: fix issues with FindClass in multithreaded environments

Added jclass reference caching and updated JNI version to 1.8

Change-Id: Ie8dbbd4b91b90bf9e4e9a6148313e46056b0d67e
Signed-off-by: Marek Gradzki <mgradzki@cisco.com>

2 files changed, 70 insertions, 25 deletions

diff --git a/vpp-api/java/jvpp/gen/jvpp_c_gen.py b/vpp-api/java/jvpp/gen/jvpp_c_gen.py
index c0efed81..e277976c 100644
--- a/vpp-api/java/jvpp/gen/jvpp_c_gen.py
+++ b/vpp-api/java/jvpp/gen/jvpp_c_gen.py
@@ -20,7 +20,48 @@ from string import Template
 def is_manually_generated(f_name):
     return f_name in {'control_ping_reply'}
 
-# TODO: cache class/method/field identifiers to achieve better performance
+
+class_reference_template = Template("""jclass ${ref_name}Class;
+""")
+
+find_class_invocation_template = Template("""
+    ${ref_name}Class = (jclass)(*env)->NewGlobalRef(env, (*env)->FindClass(env, "org/openvpp/jvpp/dto/${class_name}"));
+    if ((*env)->ExceptionCheck(env)) {
+        (*env)->ExceptionDescribe(env);
+        return JNI_ERR;
+    }""")
+
+class_cache_template = Template("""
+$class_references
+static int cache_class_references(JNIEnv* env) {
+    $find_class_invocations
+    return 0;
+}""")
+
+def generate_class_cache(func_list):
+    class_references = []
+    find_class_invocations = []
+    for f in func_list:
+        c_name = f['name']
+        class_name = util.underscore_to_camelcase_upper(c_name)
+        ref_name = util.underscore_to_camelcase(c_name)
+
+        if not util.is_reply(class_name) or util.is_ignored(c_name) or util.is_notification(c_name):
+            # TODO handle notifications
+            continue
+
+        class_references.append(class_reference_template.substitute(
+                ref_name=ref_name))
+
+        find_class_invocations.append(find_class_invocation_template.substitute(
+                ref_name=ref_name,
+                class_name=class_name))
+
+    return class_cache_template.substitute(
+            class_references="".join(class_references), find_class_invocations="".join(find_class_invocations))
+
+
+# TODO: cache method and field identifiers to achieve better performance
 # https://jira.fd.io/browse/HONEYCOMB-42
 request_class_template = Template("""
     jclass requestClass = (*env)->FindClass(env, "org/openvpp/jvpp/dto/${java_name_upper}");""")
@@ -165,7 +206,7 @@ def generate_jni_impl(func_list, inputfile):
 
 
 dto_field_id_template = Template("""
-    jfieldID ${java_name}FieldId = (*env)->GetFieldID(env, dtoClass, "${java_name}", "${jni_signature}");""")
+    jfieldID ${java_name}FieldId = (*env)->GetFieldID(env, ${class_ref_name}Class, "${java_name}", "${jni_signature}");""")
 
 default_dto_field_setter_template = Template("""
     (*env)->Set${jni_setter}(env, dto, ${java_name}FieldId, mp->${c_name});
@@ -220,12 +261,10 @@ static void vl_api_${handler_name}_t_handler (vl_api_${handler_name}_t * mp)
     vppjni_main_t * jm = &vppjni_main;
     JNIEnv *env = jm->jenv;
 
-    jclass dtoClass = (*env)->FindClass(env, "org/openvpp/jvpp/dto/${dto_name}");
-
-    jmethodID constructor = (*env)->GetMethodID(env, dtoClass, "<init>", "()V");
+    jmethodID constructor = (*env)->GetMethodID(env, ${class_ref_name}Class, "<init>", "()V");
     jmethodID callbackMethod = (*env)->GetMethodID(env, jm->callbackClass, "on${dto_name}", "(Lorg/openvpp/jvpp/dto/${dto_name};)V");
 
-    jobject dto = (*env)->NewObject(env, dtoClass, constructor);
+    jobject dto = (*env)->NewObject(env, ${class_ref_name}Class, constructor);
     $dto_setters
     (*env)->CallVoidMethod(env, jm->callback, callbackMethod, dto);
 }""")
@@ -235,6 +274,7 @@ def generate_msg_handlers(func_list, inputfile):
     for f in func_list:
         handler_name = f['name']
         dto_name = util.underscore_to_camelcase_upper(handler_name)
+        ref_name = util.underscore_to_camelcase(handler_name)
 
         if is_manually_generated(handler_name) or not util.is_reply(dto_name) or util.is_ignored(handler_name) or util.is_notification(handler_name):
             # TODO handle notifications
@@ -253,6 +293,7 @@ def generate_msg_handlers(func_list, inputfile):
 
             dto_setters += dto_field_id_template.substitute(
                     java_name=java_field_name,
+                    class_ref_name=ref_name,
                     jni_signature=jni_signature)
 
             dto_setter_template = dto_field_setter_templates[c_type]
@@ -268,6 +309,7 @@ def generate_msg_handlers(func_list, inputfile):
                 api_data=util.api_message_to_javadoc(f),
                 handler_name=handler_name,
                 dto_name=dto_name,
+                class_ref_name=ref_name,
                 dto_setters=dto_setters))
 
     return "\n".join(handlers)
@@ -293,13 +335,16 @@ def generate_handler_registration(func_list):
 
     return "".join(handler_registration)
 
-jvpp_c_template = Template("""
-/**
+
+jvpp_c_template = Template("""/**
  * This file contains JNI bindings for jvpp Java API.
  * It was generated by jvpp_c_gen.py based on $inputfile
  * (python representation of vpe.api generated by vppapigen).
  */
 
+// JAVA class reference cache
+$class_cache
+
 // JNI bindings
 $jni_implementations
 
@@ -314,6 +359,7 @@ def generate_jvpp(func_list, inputfile):
     """ Generates jvpp C file """
     print "Generating jvpp C"
 
+    class_cache = generate_class_cache(func_list)
     jni_impl = generate_jni_impl(func_list, inputfile)
     msg_handlers = generate_msg_handlers(func_list, inputfile)
     handler_registration = generate_handler_registration(func_list)
@@ -321,6 +367,7 @@ def generate_jvpp(func_list, inputfile):
     jvpp_c_file = open("jvpp_gen.h", 'w')
     jvpp_c_file.write(jvpp_c_template.substitute(
             inputfile=inputfile,
+            class_cache=class_cache,
             jni_implementations=jni_impl,
             msg_handlers=msg_handlers,
             handler_registration=handler_registration))
diff --git a/vpp-api/java/jvpp/jvpp.c b/vpp-api/java/jvpp/jvpp.c
index f1e23dc7..6cc05530 100644
--- a/vpp-api/java/jvpp/jvpp.c
+++ b/vpp-api/java/jvpp/jvpp.c
@@ -76,7 +76,7 @@ static void cleanup_rx_thread(void *arg)
 
     vppjni_lock (jm, 99);
 
-    int getEnvStat = (*jm->jvm)->GetEnv(jm->jvm, (void **)&(jm->jenv), JNI_VERSION_1_6);
+    int getEnvStat = (*jm->jvm)->GetEnv(jm->jvm, (void **)&(jm->jenv), JNI_VERSION_1_8);
     if (getEnvStat == JNI_EVERSION) {
         clib_warning ("Unsupported JNI version\n");
         jm->retval = VNET_API_ERROR_UNSUPPORTED_JNI_VERSION;
@@ -170,7 +170,7 @@ static void vl_api_control_ping_reply_t_handler
     char was_thread_connected = 0;
 
     // attach to java thread if not attached
-    int getEnvStat = (*jm->jvm)->GetEnv(jm->jvm, (void **)&(jm->jenv), JNI_VERSION_1_6);
+    int getEnvStat = (*jm->jvm)->GetEnv(jm->jvm, (void **)&(jm->jenv), JNI_VERSION_1_8);
     if (getEnvStat == JNI_EDETACHED) {
         if ((*jm->jvm)->AttachCurrentThread(jm->jvm, (void **)&(jm->jenv), NULL) != 0) {
             clib_warning("Failed to attach thread\n");
@@ -192,26 +192,21 @@ static void vl_api_control_ping_reply_t_handler
     if (was_thread_connected == 0) {
         JNIEnv *env = jm->jenv;
 
-        jclass dtoClass = (*env)->FindClass(env, "org/openvpp/jvpp/dto/ControlPingReply");
-
-        jmethodID constructor = (*env)->GetMethodID(env, dtoClass, "<init>", "()V");
+        jmethodID constructor = (*env)->GetMethodID(env, controlPingReplyClass, "<init>", "()V");
         jmethodID callbackMethod = (*env)->GetMethodID(env, jm->callbackClass, "onControlPingReply", "(Lorg/openvpp/jvpp/dto/ControlPingReply;)V");
 
-        jobject dto = (*env)->NewObject(env, dtoClass, constructor);
-
-
-        printf("vl_api_control_ping_reply_t_handler ctx=%d\n", clib_net_to_host_u32(mp->context));
+        jobject dto = (*env)->NewObject(env, controlPingReplyClass, constructor);
 
-        jfieldID contextFieldId = (*env)->GetFieldID(env, dtoClass, "context", "I");
+        jfieldID contextFieldId = (*env)->GetFieldID(env, controlPingReplyClass, "context", "I");
         (*env)->SetIntField(env, dto, contextFieldId, clib_net_to_host_u32(mp->context));
 
-        jfieldID retvalFieldId = (*env)->GetFieldID(env, dtoClass, "retval", "I");
+        jfieldID retvalFieldId = (*env)->GetFieldID(env, controlPingReplyClass, "retval", "I");
         (*env)->SetIntField(env, dto, retvalFieldId, clib_net_to_host_u32(mp->retval));
 
-        jfieldID clientIndexFieldId = (*env)->GetFieldID(env, dtoClass, "clientIndex", "I");
+        jfieldID clientIndexFieldId = (*env)->GetFieldID(env, controlPingReplyClass, "clientIndex", "I");
         (*env)->SetIntField(env, dto, clientIndexFieldId, clib_net_to_host_u32(mp->client_index));
 
-        jfieldID vpePidFieldId = (*env)->GetFieldID(env, dtoClass, "vpePid", "I");
+        jfieldID vpePidFieldId = (*env)->GetFieldID(env, controlPingReplyClass, "vpePid", "I");
         (*env)->SetIntField(env, dto, vpePidFieldId, clib_net_to_host_u32(mp->vpe_pid));
 
         (*env)->CallVoidMethod(env, jm->callback, callbackMethod, dto);
@@ -221,22 +216,25 @@ static void vl_api_control_ping_reply_t_handler
         jm->result_ready = 1;
 }
 
-
 jint JNI_OnLoad(JavaVM *vm, void *reserved) {
     vppjni_main_t * jm = &vppjni_main;
     JNIEnv* env;
-    if ((*vm)->GetEnv(vm, (void**) &env, JNI_VERSION_1_6) != JNI_OK) {
+    if ((*vm)->GetEnv(vm, (void**) &env, JNI_VERSION_1_8) != JNI_OK) {
+        return JNI_EVERSION;
+    }
+
+    if (cache_class_references(env) != 0) {
         return JNI_ERR;
     }
 
     jm->jvm = vm;
-    return JNI_VERSION_1_6;
+    return JNI_VERSION_1_8;
 }
 
 void JNI_OnUnload(JavaVM *vm, void *reserved) {
     vppjni_main_t * jm = &vppjni_main;
     JNIEnv* env;
-    if ((*vm)->GetEnv(vm, (void**) &env, JNI_VERSION_1_6) != JNI_OK) {
+    if ((*vm)->GetEnv(vm, (void**) &env, JNI_VERSION_1_8) != JNI_OK) {
         return;
     }