cleanup 'str' API

tutorials/core/multi-threaded/main.c

@@ -48,8 +48,10 @@ static void fn(struct mg_connection *c, int ev, void *ev_data) {
       mg_http_reply(c, 200, "Host: foo.com\r\n", "hi\n");
     } else {
       // Multithreading code path
-      struct thread_data *data = calloc(1, sizeof(*data));  // Worker owns it
-      data->message = mg_strdup(hm->message);               // Pass message
+      struct thread_data *data =
+          (struct thread_data *) calloc(1, sizeof(*data));  // Worker owns it
+      data->message.buf = mg_mprintf("%.*s", hm->message.len, hm->message.buf);
+      data->message.len = hm->message.len;  // Pass message
       data->conn_id = c->id;
       data->mgr = c->mgr;
       start_thread(thread_function, data);  // Start thread and pass data

tutorials/mqtt/mqtt-server/main.c

@@ -80,7 +80,8 @@ static void fn(struct mg_connection *c, int ev, void *ev_data) {
         while ((pos = mg_mqtt_next_sub(mm, &topic, &qos, pos)) > 0) {
           struct sub *sub = calloc(1, sizeof(*sub));
           sub->c = c;
-          sub->topic = mg_strdup(topic);
+          sub->topic.buf = mg_mprintf("%.*s", topic.len, topic.buf);
+          sub->topic.len = topic.len;
           sub->qos = qos;
           LIST_ADD_HEAD(struct sub, &s_subs, sub);
           MG_INFO(

tutorials/udp/ssdp-search/main.c

@@ -19,11 +19,11 @@ static void fn(struct mg_connection *c, int ev, void *ev_data) {
       size_t i, max = sizeof(hm.headers) / sizeof(hm.headers[0]);
       // Iterate over request headers
       for (i = 0; i < max && hm.headers[i].name.len > 0; i++) {
-        struct mg_str *k = &hm.headers[i].name, *v = &hm.headers[i].value;
-        if ((mg_vcasecmp(k, "SERVER") == 0) ||
-            (mg_vcasecmp(k, "LOCATION") == 0)) {
-          printf("\t%.*s -> %.*s\n", (int) k->len, k->buf, (int) v->len,
-                 v->buf);
+        struct mg_str k = hm.headers[i].name, v = hm.headers[i].value;
+        if ((mg_strcasecmp(k, mg_str("SERVER")) == 0) ||
+            (mg_strcasecmp(k, mg_str("LOCATION")) == 0)) {
+          printf("\t%.*s -> %.*s\n", (int) k.len, k.buf, (int) v.len,
+                 v.buf);
         }
       }
       printf("\n");