pnoltes commented on a change in pull request #174: Feature/pubsub inteceptors
URL: https://github.com/apache/celix/pull/174#discussion_r400134468
 
 

 ##########
 File path: bundles/pubsub/pubsub_spi/src/pubsub_interceptors_handler.c
 ##########
 @@ -0,0 +1,174 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 "celix_bundle_context.h"
+#include "celix_constants.h"
+#include "utils.h"
+
+#include "pubsub_interceptors_handler.h"
+
+typedef struct entry {
+    const celix_properties_t *properties;
+    pubsub_interceptor_t *interceptor;
+} entry_t;
+
+struct pubsub_interceptors_handler {
+    pubsub_interceptor_properties_t properties;
+
+    celix_array_list_t *interceptors;
+
+    long interceptorsTrackerId;
+
+    celix_bundle_context_t *ctx;
+
+    celix_thread_mutex_t mutex;
+};
+
+static int referenceCompare(const void *a, const void *b);
+
+static void pubsubInterceptorsHandler_addInterceptor(void *handle, void *svc, const celix_properties_t *props);
+static void pubsubInterceptorsHandler_removeInterceptor(void *handle, void *svc, const celix_properties_t *props);
+
+celix_status_t pubsubInterceptorsHandler_create(celix_bundle_context_t *ctx, const char *scope, const char *topic, pubsub_interceptors_handler_t **handler) {
+    celix_status_t status = CELIX_SUCCESS;
+
+    *handler = calloc(1, sizeof(**handler));
+    if (!*handler) {
+        status = CELIX_ENOMEM;
+    } else {
+        (*handler)->ctx = ctx;
+
+        (*handler)->properties.scope = scope;
+        (*handler)->properties.topic = topic;
+
+        (*handler)->interceptors = celix_arrayList_create();
+
+        celixThreadMutex_create(&(*handler)->mutex, NULL);
+
+        // Create service tracker here, and not in the activator
+        celix_service_tracking_options_t opts = CELIX_EMPTY_SERVICE_TRACKING_OPTIONS;
+        opts.filter.serviceName = PUBSUB_INTERCEPTOR_SERVICE_NAME;
+        opts.filter.ignoreServiceLanguage = true;
+        opts.callbackHandle = *handler;
+        opts.addWithProperties = pubsubInterceptorsHandler_addInterceptor;
+        opts.removeWithProperties = pubsubInterceptorsHandler_removeInterceptor;
+        (*handler)->interceptorsTrackerId = celix_bundleContext_trackServicesWithOptions(ctx, &opts);
+    }
+
+    return status;
+}
+
+celix_status_t pubsubInterceptorsHandler_destroy(pubsub_interceptors_handler_t *handler) {
+    celix_bundleContext_stopTracker(handler->ctx, handler->interceptorsTrackerId);
+
+    free(handler->interceptors);
+    free(handler);
+
+    return CELIX_SUCCESS;
+}
+
+void pubsubInterceptorsHandler_addInterceptor(void *handle, void *svc, const celix_properties_t *props) {
+    pubsub_interceptors_handler_t *handler = handle;
+    celixThreadMutex_lock(&handler->mutex);
+
+    bool exists = false;
+    for (int i = 0; i < arrayList_size(handler->interceptors); i++) {
+        entry_t *entry = arrayList_get(handler->interceptors, i);
+        if (entry->interceptor == svc) {
+            exists = true;
+        }
+    }
+    if (!exists) {
+        entry_t *entry = calloc(1, sizeof(*entry));
+        entry->properties = props;
+        entry->interceptor = svc;
+        celix_arrayList_add(handler->interceptors, entry);
+
+        celix_arrayList_sort(handler->interceptors, referenceCompare);
+    }
+
+    celixThreadMutex_unlock(&handler->mutex);
+}
+
+void pubsubInterceptorsHandler_removeInterceptor(void *handle, void *svc, __attribute__((unused)) const celix_properties_t *props) {
+    pubsub_interceptors_handler_t *handler = handle;
+    for (int i = 0; i < arrayList_size(handler->interceptors); i++) {
+        entry_t *entry = arrayList_get(handler->interceptors, i);
+        if (entry->interceptor == svc) {
+            arrayList_remove(handler->interceptors, i);
+            break;
+        }
+    }
+}
+
+bool pubsubInterceptorHandler_invokePreSend(pubsub_interceptors_handler_t *handler, const char *messageType, const uint32_t messageId, const void *message, celix_properties_t *metadata) {
+    bool cont = true;
+    for (int i = arrayList_size(handler->interceptors) - 1; i >= 0; i--) {
+        entry_t *entry = arrayList_get(handler->interceptors, i);
+
+        cont = entry->interceptor->preSend(entry->interceptor->handle, handler->properties, messageType, messageId, message, metadata);
+        if (!cont) {
+            break;
+        }
+    }
+
+    return cont;
+}
+
+void pubsubInterceptorHandler_invokePostSend(pubsub_interceptors_handler_t *handler, const char *messageType, const uint32_t messageId, const void *message, celix_properties_t *metadata) {
+    for (int i = arrayList_size(handler->interceptors) - 1; i >= 0; i--) {
+        entry_t *entry = arrayList_get(handler->interceptors, i);
+
+        entry->interceptor->postSend(entry->interceptor->handle, handler->properties, messageType, messageId, message, metadata);
+    }
+}
+
+bool pubsubInterceptorHandler_invokePreReceive(pubsub_interceptors_handler_t *handler, const char *messageType, const uint32_t messageId, const void *message, celix_properties_t *metadata) {
+    bool cont = true;
 
 Review comment:
   Are we sure that the metadata is not NULL?
   
   If so, I expected this to be an optimalization in the wire protocol that is there is no metadata (or a configuration is added to skip the metadata) that no celix_properties will be created.
   
   And then in the interceptor handler only create a empty metadata if there a interceptors registered.
   
   This way we can keep the overhead to a minimum if there is no metadata / interceptors
   
   see als invokePreSend

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