Improve PubSub subscriber example (#1811)

* PubSub: Fix memleaks in subscriber tutorial

* PubSub: Stack-allocate in the subscriber tutorial

* PubSub: In subscriber tutorial, evaluate receive error code; quit early

* PubSub: In subscriber example, use logging API instead of printf

* PubSub: Reduce the max indendation of the subscriber example; Add comments

* PubSub: Use short blocking wait times in subscriber example

* PubSub: Reduce the max line length in the subscriber example

examples/pubsub/tutorial_pubsub_subscribe.c

@@ -10,7 +10,6 @@
  * PubSub subscriber API.
 */
 #include <signal.h>
-#include <stdio.h>
 #include "ua_pubsub_networkmessage.h"
 #include "ua_log_stdout.h"
 #include "ua_server.h"
@@ -29,42 +28,68 @@ static void
 subscriptionPollingCallback(UA_Server *server, UA_PubSubConnection *connection) {
     UA_ByteString buffer;
     if (UA_ByteString_allocBuffer(&buffer, 512) != UA_STATUSCODE_GOOD) {
-        UA_LOG_ERROR(UA_Log_Stdout, UA_LOGCATEGORY_SERVER, "Message buffer allocation failed!");
+        UA_LOG_ERROR(UA_Log_Stdout, UA_LOGCATEGORY_SERVER,
+                     "Message buffer allocation failed!");
         return;
     }
-    connection->channel->receive(connection->channel, &buffer, NULL, 300000);
-    if (buffer.length > 0) {
-        UA_LOG_INFO(UA_Log_Stdout, UA_LOGCATEGORY_USERLAND, "Message received:");
-        UA_NetworkMessage *actualNetworkMessage = (UA_NetworkMessage *) UA_calloc(1, sizeof(UA_NetworkMessage));
-        size_t currentPosition = 0;
-        if (!actualNetworkMessage) {
-            UA_LOG_ERROR(UA_Log_Stdout, UA_LOGCATEGORY_SERVER, "Networkmessage allocation failed!");
-            UA_ByteString_deleteMembers(&buffer);
-            return;
-        }
-        UA_NetworkMessage_decodeBinary(&buffer, &currentPosition, actualNetworkMessage);
-        printf("Message length: %zu\n", buffer.length);
-        if (actualNetworkMessage->networkMessageType == UA_NETWORKMESSAGE_DATASET) {
-            if ((actualNetworkMessage->payloadHeaderEnabled && (actualNetworkMessage->payloadHeader.dataSetPayloadHeader.count >= 1)) ||
-                (!actualNetworkMessage->payloadHeaderEnabled)) {
-                if (actualNetworkMessage->payload.dataSetPayload.dataSetMessages[0].header.dataSetMessageType ==
-                    UA_DATASETMESSAGE_DATAKEYFRAME) {
-                    for (int i = 0; i < actualNetworkMessage->payload.dataSetPayload.dataSetMessages[0].data.keyFrameData.fieldCount; i++) {
-                        const UA_DataType *currentType = actualNetworkMessage->payload.dataSetPayload.dataSetMessages[0].data.keyFrameData.dataSetFields[i].value.type;
-                        if (currentType == &UA_TYPES[UA_TYPES_BYTE]) {
-                            printf("Message content: [Byte] \n\tReceived data: %i\n",
-                                   *((UA_Byte *) actualNetworkMessage->payload.dataSetPayload.dataSetMessages[0].data.keyFrameData.dataSetFields[i].value.data));
-                        } else if (currentType == &UA_TYPES[UA_TYPES_DATETIME]) {
-                            UA_DateTimeStruct receivedTime = UA_DateTime_toStruct(
-                                    *((UA_DateTime *) actualNetworkMessage->payload.dataSetPayload.dataSetMessages[0].data.keyFrameData.dataSetFields[i].value.data));
-                            printf("Message content: [DateTime] \n\tReceived date: %02i-%02i-%02i Received time: %02i:%02i:%02i\n", receivedTime.year, receivedTime.month,
-                                   receivedTime.day, receivedTime.hour, receivedTime.min, receivedTime.sec);
-                        }
-                    }
-                }
-            }
+
+    /* Receive the message. Blocks for 5ms */
+    UA_StatusCode retval =
+        connection->channel->receive(connection->channel, &buffer, NULL, 5);
+    if(retval != UA_STATUSCODE_GOOD || buffer.length == 0) {
+        /* Workaround!! Reset buffer length. Receive can set the length to zero.
+         * Then the buffer is not deleted because no memory allocation is
+         * assumed.
+         * TODO: Return an error code in 'receive' instead of setting the buf
+         * length to zero. */
+        buffer.length = 512;
+        UA_ByteString_deleteMembers(&buffer);
+        return;
+    }
+
+    /* Decode the message */
+    UA_LOG_INFO(UA_Log_Stdout, UA_LOGCATEGORY_USERLAND,
+                "Message length: %zu", buffer.length);
+    UA_NetworkMessage networkMessage;
+    memset(&networkMessage, 0, sizeof(UA_NetworkMessage));
+    size_t currentPosition = 0;
+    UA_NetworkMessage_decodeBinary(&buffer, &currentPosition, &networkMessage);
+    UA_ByteString_deleteMembers(&buffer);
+
+    /* Is this the correct message type? */
+    if(networkMessage.networkMessageType != UA_NETWORKMESSAGE_DATASET)
+        goto cleanup;
+
+    /* At least one DataSetMessage in the NetworkMessage? */
+    if(networkMessage.payloadHeaderEnabled &&
+       networkMessage.payloadHeader.dataSetPayloadHeader.count < 1)
+        goto cleanup;
+
+    /* Is this a KeyFrame-DataSetMessage? */
+    UA_DataSetMessage *dsm = &networkMessage.payload.dataSetPayload.dataSetMessages[0];
+    if(dsm->header.dataSetMessageType != UA_DATASETMESSAGE_DATAKEYFRAME)
+        goto cleanup;
+
+    /* Loop over the fields and print well-known content types */
+    for(int i = 0; i < dsm->data.keyFrameData.fieldCount; i++) {
+        const UA_DataType *currentType = dsm->data.keyFrameData.dataSetFields[i].value.type;
+        if(currentType == &UA_TYPES[UA_TYPES_BYTE]) {
+            UA_Byte value = *(UA_Byte *)dsm->data.keyFrameData.dataSetFields[i].value.data;
+            UA_LOG_INFO(UA_Log_Stdout, UA_LOGCATEGORY_USERLAND,
+                        "Message content: [Byte] \tReceived data: %i", value);
+        } else if (currentType == &UA_TYPES[UA_TYPES_DATETIME]) {
+            UA_DateTime value = *(UA_DateTime *)dsm->data.keyFrameData.dataSetFields[i].value.data;
+            UA_DateTimeStruct receivedTime = UA_DateTime_toStruct(value);
+            UA_LOG_INFO(UA_Log_Stdout, UA_LOGCATEGORY_USERLAND,
+                        "Message content: [DateTime] \t"
+                        "Received date: %02i-%02i-%02i Received time: %02i:%02i:%02i",
+                        receivedTime.year, receivedTime.month, receivedTime.day,
+                        receivedTime.hour, receivedTime.min, receivedTime.sec);
         }
     }
+
+ cleanup:
+    UA_NetworkMessage_deleteMembers(&networkMessage);
 }
 
 int main(void) {
@@ -72,8 +97,10 @@ int main(void) {
     signal(SIGTERM, stopHandler);
 
     UA_ServerConfig *config = UA_ServerConfig_new_minimal(4801, NULL);
-    /* Details about the PubSubTransportLayer can be found inside the tutorial_pubsub_connection */
-    config->pubsubTransportLayers = (UA_PubSubTransportLayer *) UA_malloc(sizeof(UA_PubSubTransportLayer));
+    /* Details about the PubSubTransportLayer can be found inside the
+     * tutorial_pubsub_connection */
+    config->pubsubTransportLayers = (UA_PubSubTransportLayer *)
+        UA_malloc(sizeof(UA_PubSubTransportLayer));
     if (!config->pubsubTransportLayers) {
         UA_ServerConfig_delete(config);
         return -1;
@@ -85,26 +112,34 @@ int main(void) {
     UA_PubSubConnectionConfig connectionConfig;
     memset(&connectionConfig, 0, sizeof(connectionConfig));
     connectionConfig.name = UA_STRING("UDP-UADP Connection 1");
-    connectionConfig.transportProfileUri = UA_STRING("http://opcfoundation.org/UA-Profile/Transport/pubsub-udp-uadp");
+    connectionConfig.transportProfileUri =
+        UA_STRING("http://opcfoundation.org/UA-Profile/Transport/pubsub-udp-uadp");
     connectionConfig.enabled = UA_TRUE;
-    UA_NetworkAddressUrlDataType networkAddressUrl = {UA_STRING_NULL , UA_STRING("opc.udp://224.0.0.22:4840/")};
-    UA_Variant_setScalar(&connectionConfig.address, &networkAddressUrl, &UA_TYPES[UA_TYPES_NETWORKADDRESSURLDATATYPE]);
+    UA_NetworkAddressUrlDataType networkAddressUrl =
+        {UA_STRING_NULL , UA_STRING("opc.udp://224.0.0.22:4840/")};
+    UA_Variant_setScalar(&connectionConfig.address, &networkAddressUrl,
+                         &UA_TYPES[UA_TYPES_NETWORKADDRESSURLDATATYPE]);
     UA_NodeId connectionIdent;
-    UA_StatusCode retval = UA_Server_addPubSubConnection(server, &connectionConfig, &connectionIdent);
-    if(retval == UA_STATUSCODE_GOOD){
-        UA_LOG_INFO(UA_Log_Stdout, UA_LOGCATEGORY_SERVER, "The PubSub Connection was created successfully!");
-    }
+    UA_StatusCode retval =
+        UA_Server_addPubSubConnection(server, &connectionConfig, &connectionIdent);
+    if(retval == UA_STATUSCODE_GOOD)
+        UA_LOG_INFO(UA_Log_Stdout, UA_LOGCATEGORY_SERVER,
+                    "The PubSub Connection was created successfully!");
 
-    /* The following lines register the listening on the configured multicast address and configure
-     * a repeated job, which is used to handle received messages. */
-    UA_PubSubConnection *connection = UA_PubSubConnection_findConnectionbyId(server, connectionIdent);
-    if (connection != NULL) {
+    /* The following lines register the listening on the configured multicast
+     * address and configure a repeated job, which is used to handle received
+     * messages. */
+    UA_PubSubConnection *connection =
+        UA_PubSubConnection_findConnectionbyId(server, connectionIdent);
+    if(connection != NULL) {
         UA_StatusCode rv = connection->channel->regist(connection->channel, NULL);
         if (rv == UA_STATUSCODE_GOOD) {
             UA_UInt64 subscriptionCallbackId;
-            UA_Server_addRepeatedCallback(server, (UA_ServerCallback)subscriptionPollingCallback, connection, 5, &subscriptionCallbackId);
+            UA_Server_addRepeatedCallback(server, (UA_ServerCallback)subscriptionPollingCallback,
+                                          connection, 100, &subscriptionCallbackId);
         } else {
-            UA_LOG_WARNING(UA_Log_Stdout, UA_LOGCATEGORY_SERVER, "register channel failed: 0x%x!", rv);
+            UA_LOG_WARNING(UA_Log_Stdout, UA_LOGCATEGORY_SERVER, "register channel failed: %s!",
+                           UA_StatusCode_name(rv));
         }
     }