jvpp: object model for jvpp generator (VPP-1184)

[vpp.git] / src / vpp-api / java / jvpp / gen / jvppgen / jni_msg_handlers_gen.py

diff --git a/src/vpp-api/java/jvpp/gen/jvppgen/jni_msg_handlers_gen.py b/src/vpp-api/java/jvpp/gen/jvppgen/jni_msg_handlers_gen.py
new file mode 100755 (executable)
index 0000000..8f6410f
--- /dev/null
+++ b/src/vpp-api/java/jvpp/gen/jvppgen/jni_msg_handlers_gen.py
@@ -0,0 +1,105 @@
+#!/usr/bin/env python2
+#
+# Copyright (c) 2018 Cisco and/or its affiliates.
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at:
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+from string import Template
+
+from jni_common_gen import generate_c2j_swap
+from jvpp_model import is_dump, is_request, is_control_ping, is_control_ping_reply, is_retval
+
+
+def generate_jni_handlers(model):
+    """
+    Generates msg handlers for all messages except for dumps and requests (handled by vpp, not client).
+    :param model: meta-model of VPP API used for jVPP generation.
+    """
+    jni_impl = []
+    for msg in model.messages:
+        msg_name = msg.name
+        if is_control_ping(msg) or is_control_ping_reply(msg):
+            # Skip control ping managed by jvpp registry.
+            continue
+        if is_dump(msg) or is_request(msg):
+            continue
+
+        jni_impl.append(_MSG_HANDLER_TEMPLATE.substitute(
+            c_name=msg_name,
+            json_filename=model.json_api_files,
+            json_definition=msg.doc,
+            plugin_name=model.plugin_name,
+            err_handler=_generate_error_handler(msg),
+            class_ref_name=msg.java_name_lower,
+            dto_name=msg.java_name_upper,
+            dto_setters=generate_c2j_swap(msg, object_ref_name="dto", struct_ref_name="mp")
+        ))
+    return "".join(jni_impl)
+
+_MSG_HANDLER_TEMPLATE = Template("""
+/**
+ * Handler for ${c_name} message.
+ * Generated based on $json_filename:
+$json_definition
+ */
+static void vl_api_${c_name}_t_handler (vl_api_${c_name}_t * mp)
+{
+    ${plugin_name}_main_t *plugin_main = &${plugin_name}_main;
+    JNIEnv *env = jvpp_main.jenv;
+    jthrowable exc;
+$err_handler
+
+    if (CLIB_DEBUG > 1)
+        clib_warning ("Received ${c_name} event message");
+
+    jmethodID constructor = (*env)->GetMethodID(env, ${class_ref_name}Class, "<init>", "()V");
+
+    // User does not have to provide callbacks for all VPP messages.
+    // We are ignoring messages that are not supported by user.
+    (*env)->ExceptionClear(env); // just in case exception occurred in different place and was not properly cleared
+    jmethodID callbackMethod = (*env)->GetMethodID(env, plugin_main->callbackClass, "on${dto_name}", "(Lio/fd/vpp/jvpp/${plugin_name}/dto/${dto_name};)V");
+    exc = (*env)->ExceptionOccurred(env);
+    if (exc) {
+        clib_warning("Unable to extract on${dto_name} method reference from ${plugin_name} plugin's callbackClass. Ignoring message.\\n");
+        (*env)->ExceptionDescribe(env);
+        (*env)->ExceptionClear(env);
+        return;
+    }
+
+    jobject dto = (*env)->NewObject(env, ${class_ref_name}Class, constructor);
+$dto_setters
+
+    (*env)->CallVoidMethod(env, plugin_main->callbackObject, callbackMethod, dto);
+    // free DTO as per http://stackoverflow.com/questions/1340938/memory-leak-when-calling-java-code-from-c-using-jni
+    (*env)->DeleteLocalRef(env, dto);
+}""")
+
+
+def _generate_error_handler(msg):
+    err_handler = ""
+    for field in msg.fields:
+        if is_retval(field):
+            err_handler = _ERR_HANDLER_TEMPLATE.substitute(name=msg.name)
+    return err_handler
+
+# Code fragment for checking result of the operation before sending request reply.
+# Error checking is optional (some messages, e.g. detail messages do not have retval field).
+_ERR_HANDLER_TEMPLATE = Template("""
+    // for negative result don't send callback message but send error callback
+    if (mp->retval<0) {
+        call_on_error("${name}", mp->context, mp->retval, plugin_main->callbackClass, plugin_main->callbackObject, callbackExceptionClass);
+        return;
+    }
+    if (mp->retval == VNET_API_ERROR_IN_PROGRESS) {
+        clib_warning("Result in progress");
+        return;
+    }""")