From ef3883ed1598799b5934d74cb962e73f1211fdc2 Mon Sep 17 00:00:00 2001
From: Hans Dijkema <hans@dijkewijk.nl>
Date: Fri, 10 Apr 2026 10:16:13 +0200
Subject: [PATCH] threading / event callback

---
 rktwebview.cpp | 35 +++++++++++++++++++++++++++++++++++
 rktwebview.h   |  2 ++
 2 files changed, 37 insertions(+)

diff --git a/rktwebview.cpp b/rktwebview.cpp
index c9a680a..5782645 100644
--- a/rktwebview.cpp
+++ b/rktwebview.cpp
@@ -2,6 +2,7 @@
 #include <chrono>
 #include <stdint.h>
 #include <string.h>
+#include <thread>
 
 #ifdef _WIN32
 #include <windows.h>
@@ -40,6 +41,7 @@ typedef struct {
     ShmQueue *command_queue;
     ShmQueue *command_result_queue;
     ShmQueue *event_queue;
+    void (*evt_cb)(int entries);
 #ifdef _WIN32
     HANDLE rkt_webview_prg_pid;
 #else
@@ -169,6 +171,23 @@ bool runRktWebview(Handle_t *handler)
 // Main C Interface
 /////////////////////////////////////////////////////////////////////
 
+static bool guard_go_on = false;
+static std::thread *guard_thread = nullptr;
+
+void rkt_evt_guard(void)
+{
+    int waiting = rkt_webview_events_waiting();
+    while(guard_go_on) {
+        int w = rkt_webview_events_waiting();
+        if (w != waiting) {
+            if (handler->evt_cb != nullptr) {
+                handler->evt_cb(w);
+            }
+            waiting = w;
+        }
+        std::this_thread::sleep_for(std::chrono::milliseconds(5));
+    }
+}
 
 void rkt_webview_cleanup()
 {
@@ -180,6 +199,12 @@ void rkt_webview_cleanup()
         // Cleaning up when exiting the current custodian is not enough.
 
         if (handler->valid) {
+            INFO0("Stopping evt_guard\n");
+            guard_go_on = false;
+            guard_thread->join();
+            delete guard_thread;
+            guard_thread = nullptr;
+
             INFO0("Sending quit message\n");
             handler->command_queue->enqueue(CMD_QUIT);
             INFO0("Message sent\n");
@@ -228,6 +253,7 @@ void rkt_webview_init()
         handler->name = buf;
         handler->function_calls = 0;
         handler->events = 0;
+        handler->evt_cb = nullptr;
 
         handler->shm_size = SHM_SIZE;
         handler->shm = new Shm(handler->name.data(), handler->shm_size, true);
@@ -241,6 +267,9 @@ void rkt_webview_init()
         handler->rkt_webview_prg_started = runRktWebview(handler);
         if (!handler->rkt_webview_prg_started) { handler->valid = false; }
 #endif
+        // Start event guard thread
+        guard_go_on = true;
+        guard_thread = new std::thread(rkt_evt_guard);
     } else {
         handler->function_calls++;
     }
@@ -272,6 +301,12 @@ static inline bool validHandle()
 #define FAIL_CALL_JS if (!validHandle()) { return nullptr; }
 #define FAIL_INFO FAIL_CALL_JS
 
+void rkt_webview_register_evt_callback(void (*f)(int))
+{
+    rkt_webview_init();
+    handler->evt_cb = f;
+}
+
 rkt_wv_context_t rkt_webview_new_context(const char *boilerplate_js, const char *optional_server_cert_pem)
 {
     rkt_webview_init();
diff --git a/rktwebview.h b/rktwebview.h
index c2e2ce8..f83bf9c 100644
--- a/rktwebview.h
+++ b/rktwebview.h
@@ -13,6 +13,8 @@ extern "C" {
 RKTWEBVIEW_EXPORT void rkt_webview_env(const char *env_cmds[]);
 RKTWEBVIEW_EXPORT void rkt_webview_init();
 RKTWEBVIEW_EXPORT void rkt_webview_cleanup();
+RKTWEBVIEW_EXPORT void rkt_webview_register_evt_callback(void (*f)(int));
+
 RKTWEBVIEW_EXPORT void rkt_webview_set_loglevel(rkt_webview_loglevel_t l);
 RKTWEBVIEW_EXPORT rkt_data_t *rkt_webview_info();