fix vpp string type api implementation

 - separate static string functions to string_t.h library
 - ignore string limit value for now. We would need to create
   wrapper class for string to support max length in java.
   API example:
   [
       "string",
       "version",
       {
           "limit": 32
       }
   ]

Change-Id: I60a8a2c56397d54d49544551dc91733e12a0a0ea
Signed-off-by: Michal Cmarada <mcmarada@cisco.com>

4 files changed, 71 insertions, 57 deletions

diff --git a/java/jvpp-common/string_t.h b/java/jvpp-common/string_t.h
new file mode 100644
index 0000000..8a2b3cc
--- /dev/null
+++ b/java/jvpp-common/string_t.h
@@ -0,0 +1,68 @@
+/*
+ * Copyright (c) 2019 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.
+ */
+
+#include <jni.h>
+#include <vlibapi/api_types.h>
+
+#ifndef JVPP_STRING_T_H
+#define JVPP_STRING_T_H
+
+#endif //JVPP_STRING_T_H
+
+//
+// /**
+// * Returns the length of jstring as size_t
+// */
+static size_t jstr_length(JNIEnv *env, jstring string)
+{
+    return ((int) (*env)->GetStringUTFLength(env, string));
+}
+
+// /**
+// * Host to network byte order conversion for string type. Converts String in Java to VPP string type.
+// * typedef struct
+// * {
+// *   u32 length;
+// *   u8 buf[0];
+// * } __attribute__ ((packed)) vl_api_string_t;
+// */
+static void _host_to_net_string(JNIEnv * env, jstring javaString, vl_api_string_t * vl_api_string)
+{
+    const char *nativeString;
+    // prevent null, which causes jni to crash
+    if (NULL != javaString) {
+        nativeString = (*env)->GetStringUTFChars(env, javaString, 0);
+    } else{
+        nativeString = "";
+    }
+
+    vl_api_to_api_string(jstr_length(env, javaString) + 1, nativeString, vl_api_string);
+
+    (*env)->ReleaseStringUTFChars(env, javaString, nativeString);
+}
+
+//
+// /**
+// * Network to host byte order conversion for string type. Converts VPP string type to String in Java
+// * typedef struct
+// * {
+// *   u32 length;
+// *   u8 buf[0];
+// * } __attribute__ ((packed)) vl_api_string_t;
+// */
+static jstring _net_to_host_string(JNIEnv * env, const vl_api_string_t * _net)
+{
+    return (*env)->NewStringUTF(env, (char *)_net->buf);
+}
diff --git a/java/jvpp-core/jvpp_core.c b/java/jvpp-core/jvpp_core.c
index da8ab09..618793a 100644
--- a/java/jvpp-core/jvpp_core.c
+++ b/java/jvpp-core/jvpp_core.c
@@ -25,6 +25,7 @@
 #include <vlibmemory/api.h>
 #include <jni.h>
 #include <jvpp_core.h>
+#include <jvpp-common/string_t.h>
 
 
 // TODO: generate jvpp_plugin_name.c files (or at least reuse plugin's main structure)
@@ -106,31 +107,3 @@ void JNI_OnUnload(JavaVM *vm, void *reserved) {
     }
     delete_class_references(env);
 }
-
-
-static void _host_to_net_string(JNIEnv * env, jstring javaString, vl_api_string_t * vl_api_string)
-{
-    const char *nativeString;
-    // prevent null, which causes jni to crash
-    if (NULL != javaString) {
-        nativeString = (*env)->GetStringUTFChars(env, javaString, 0);
-    } else{
-        nativeString = "";
-    }
-
-    vl_api_to_api_string(jstr_length(env, javaString) + 1, nativeString, vl_api_string);
-
-    (*env)->ReleaseStringUTFChars(env, javaString, nativeString);
-}
-
-
-static jstring _net_to_host_string(JNIEnv * env, const vl_api_string_t * _net)
-{
-    return (*env)->NewStringUTF(env, (char *)_net->buf);
-}
-
-
-static size_t jstr_length(JNIEnv *env, jstring string)
-{
-    return ((int) (*env)->GetStringUTFLength(env, string));
-}
diff --git a/java/jvpp-core/jvpp_core.h b/java/jvpp-core/jvpp_core.h
index 032dd33..f310096 100644
--- a/java/jvpp-core/jvpp_core.h
+++ b/java/jvpp-core/jvpp_core.h
@@ -19,32 +19,3 @@
 #include <vlibapi/api_types.h>
 
 #endif //VPP_JVPP_CORE_H
-
-// /**
-// * Host to network byte order conversion for string type. Converts String in Java to VPP string type.
-// * typedef struct
-// * {
-// *   u32 length;
-// *   u8 buf[0];
-// * } __attribute__ ((packed)) vl_api_string_t;
-// */
-static  void _host_to_net_string(JNIEnv * env, jstring javaString, vl_api_string_t * vl_api_string);
-
-
-//
-// /**
-// * Network to host byte order conversion for string type. Converts VPP string type to String in Java
-// * typedef struct
-// * {
-// *   u32 length;
-// *   u8 buf[0];
-// * } __attribute__ ((packed)) vl_api_string_t;
-// */
-static jstring _net_to_host_string(JNIEnv * env, const vl_api_string_t * _net);
-
-
-//
-// /**
-// * Returns the length of jstring as size_t
-// */
-static size_t jstr_length(JNIEnv *env, jstring string);
diff --git a/java/jvpp/gen/jvppgen/jvpp_model.py b/java/jvpp/gen/jvppgen/jvpp_model.py
index c83b045..1b406ba 100755
--- a/java/jvpp/gen/jvppgen/jvpp_model.py
+++ b/java/jvpp/gen/jvppgen/jvpp_model.py
@@ -579,6 +579,8 @@ class JVppModel(object):
         type_name = _extract_type_name(field[0])
 
         if type_name in self._types_by_name:
+            if field[0] == "string":
+                return Field(field[1], self._types_by_name[type_name])
             if len(field) > 2:
                 # Array field
                 array_len_field = None