From 5eb80b12008f403b26e9365dbcee911969662e35 Mon Sep 17 00:00:00 2001
From: Mikhail Burakov <mburakov@mailbox.org>
Date: Sat, 28 Jan 2023 14:56:06 +0100
Subject: Implement keepalive and pings

---
 main.c | 28 ++++++++++++++++++++++------
 1 file changed, 22 insertions(+), 6 deletions(-)

(limited to 'main.c')

diff --git a/main.c b/main.c
index dac79fb..5fbfa89 100644
--- a/main.c
+++ b/main.c
@@ -612,8 +612,9 @@ int main(int argc, char* argv[]) {
     LOGE("Failed to connect mqtt socket (%s)", strerror(errno));
     goto close_mqtt;
   }
-  // TODO(mburakov): Implement keepalive
-  if (!MqttConnect(g_service.mqtt, 65535)) {
+  uint64_t now = MillisNow();
+  static const uint16_t mqtt_keepalive = UINT16_MAX;
+  if (!MqttConnect(g_service.mqtt, mqtt_keepalive)) {
     LOGE("Failed to connect mqtt (%s)", strerror(errno));
     goto close_mqtt;
   }
@@ -633,10 +634,25 @@ int main(int argc, char* argv[]) {
 
   BufferCreate(&g_service.mqtt_buffer);
   while (!g_signal) {
-    enum IoMuxerResult result = IoMuxerIterate(&g_service.io_muxer, -1);
-    if (result == kIoMuxerResultError && errno != EINTR) {
-      LOGE("Failed to iterate iomuxer (%s)", strerror(errno));
-      OnSignal(SIGABRT);
+    uint64_t timeout = now + mqtt_keepalive * 1000ull - MillisNow();
+    switch (IoMuxerIterate(&g_service.io_muxer, (int)timeout)) {
+      case kIoMuxerResultSuccess:
+        break;
+      case kIoMuxerResultTimeout:
+        now = MillisNow();
+        if (!MqttPing(g_service.mqtt)) {
+          LOGE("Failed to ping mqtt broker (%s)", strerror(errno));
+          OnSignal(SIGABRT);
+        }
+        break;
+      case kIoMuxerResultError:
+        if (errno != EINTR) {
+          LOGE("Failed to iterate iomuxer (%s)", strerror(errno));
+          OnSignal(SIGABRT);
+        }
+        break;
+      default:
+        __builtin_unreachable();
     }
   }
   twalk(g_service.messages, UnrefLuaCallbacks);
-- 
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