webui: slightly reduce wsRegister() overhead

Since there are no dynamic callbacks registered at setup(),
use simple function pointers as the input type.

Internal type is still std::func, though
(and not yet sure how to get rid of it correctly)

code/espurna/debug.cpp

@@ -186,7 +186,7 @@ void formatAndSend(const char* format, va_list args) {
         return;
     }
 
-    const size_t BufferSize { len + 1 };
+    const size_t BufferSize { static_cast<size_t>(len) + 1 };
     auto* buffer = new (std::nothrow) char[BufferSize];
     if (!buffer) {
         return;

code/espurna/ws.cpp

@@ -146,27 +146,27 @@ void wsPostSequence(const ws_on_send_callback_list_t& cbs) {
 
 // -----------------------------------------------------------------------------
 
-ws_callbacks_t& ws_callbacks_t::onVisible(ws_on_send_callback_f cb) {
+ws_callbacks_t& ws_callbacks_t::onVisible(ws_callbacks_t::on_send_f cb) {
     on_visible.push_back(cb);
     return *this;
 }
 
-ws_callbacks_t& ws_callbacks_t::onConnected(ws_on_send_callback_f cb) {
+ws_callbacks_t& ws_callbacks_t::onConnected(ws_callbacks_t::on_send_f cb) {
     on_connected.push_back(cb);
     return *this;
 }
 
-ws_callbacks_t& ws_callbacks_t::onData(ws_on_send_callback_f cb) {
+ws_callbacks_t& ws_callbacks_t::onData(ws_callbacks_t::on_send_f cb) {
     on_data.push_back(cb);
     return *this;
 }
 
-ws_callbacks_t& ws_callbacks_t::onAction(ws_on_action_callback_f cb) {
+ws_callbacks_t& ws_callbacks_t::onAction(ws_callbacks_t::on_action_f cb) {
     on_action.push_back(cb);
     return *this;
 }
 
-ws_callbacks_t& ws_callbacks_t::onKeyCheck(ws_on_keycheck_callback_f cb) {
+ws_callbacks_t& ws_callbacks_t::onKeyCheck(ws_callbacks_t::on_keycheck_f cb) {
     on_keycheck.push_back(cb);
     return *this;
 }

code/espurna/ws.h

@@ -36,16 +36,22 @@ using ws_on_send_callback_f = std::function<void(JsonObject& root)>;
 using ws_on_action_callback_f = std::function<void(uint32_t client_id, const char * action, JsonObject& data)>;
 using ws_on_keycheck_callback_f = std::function<bool(const char * key, JsonVariant& value)>;
 
+// TODO: use iterators as inputs for Post(), avoid depending on vector / any specific container
 using ws_on_send_callback_list_t = std::vector<ws_on_send_callback_f>;
 using ws_on_action_callback_list_t = std::vector<ws_on_action_callback_f>;
 using ws_on_keycheck_callback_list_t = std::vector<ws_on_keycheck_callback_f>;
 
 struct ws_callbacks_t {
-    ws_callbacks_t& onVisible(ws_on_send_callback_f);
-    ws_callbacks_t& onConnected(ws_on_send_callback_f);
-    ws_callbacks_t& onData(ws_on_send_callback_f);
-    ws_callbacks_t& onAction(ws_on_action_callback_f);
-    ws_callbacks_t& onKeyCheck(ws_on_keycheck_callback_f);
+    using on_send_f = void(*)(JsonObject&);
+    ws_callbacks_t& onVisible(on_send_f);
+    ws_callbacks_t& onConnected(on_send_f);
+    ws_callbacks_t& onData(on_send_f);
+
+    using on_action_f = void(*)(uint32_t, const char*, JsonObject&);
+    ws_callbacks_t& onAction(on_action_f);
+
+    using on_keycheck_f = bool(*)(const char*, JsonVariant&);
+    ws_callbacks_t& onKeyCheck(on_keycheck_f);
 
     ws_on_send_callback_list_t on_visible;
     ws_on_send_callback_list_t on_connected;
@@ -70,7 +76,7 @@ bool wsDebugSend(const char* prefix, const char* message);
 // WARNING: callback lists are taken by reference! make sure that list is ether:
 // - std::move(...)'ed to give control of the callback list to us
 // - persistent and will be available after the current block ends (global, heap-allocated, etc.)
-//   de-allocation is not expected e.g. ws_callbacks_t from wsRegister() is never destroyed
+//   de-allocation is not expected e.g. referenced struct from `wsRegister()` is never destroyed
 
 void wsPost(uint32_t client_id, ws_on_send_callback_f&& cb);
 void wsPost(ws_on_send_callback_f&& cb);