Add timers module

Allows a polled timer to be set for a future event. The timeout values are suitable for passing to g_obj_wait() or poll().
2025-08-20 09:48:48 +01:00
parent d8bce01e45
commit 3700867e87
7 changed files with 262 additions and 1 deletions
@@ -0,0 +1,94 @@
+/**
+ * xrdp: A Remote Desktop Protocol server.
+ *
+ * Copyright (C) Jay Sorg 2004-2025
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+/**
+ * @file common/timers.h
+ * @brief Timers and related functions (declarations)
+ * @author Matt Burt
+  */
+
+#if defined(HAVE_CONFIG_H)
+#include "config_ac.h"
+#endif
+
+#include "os_calls.h"
+#include "timers.h"
+
+struct timers_oneshot
+{
+    unsigned int add_time;  // Time event was added from_g_get_elapsed_ms()
+    int trigger_time;
+};
+
+/******************************************************************************/
+struct timers_oneshot *
+timers_oneshot_init(int ms)
+{
+    struct timers_oneshot *t = (struct timers_oneshot *)malloc(sizeof(*t));
+    if (t != NULL)
+    {
+        t->add_time = g_get_elapsed_ms();
+        t->trigger_time = (ms <= 0) ? 0 : ms;
+    }
+    return t;
+}
+
+/******************************************************************************/
+int
+timers_oneshot_get_remaining(struct timers_oneshot *timer,
+                             unsigned int now)
+{
+    int rv = -1;
+    if (timer != NULL)
+    {
+        if (timer->trigger_time == 0)
+        {
+            rv = 0;
+        }
+        else
+        {
+            rv = timer->trigger_time - (int)(now - timer->add_time);
+            if (rv <= 0)
+            {
+                rv = 0;
+                // (pathological) Make sure the timer doesn't stop
+                // triggering if it isn't attended to for the rollover
+                // period (~20 days for a 32-bit timer).
+                timer->trigger_time = 0;
+            }
+        }
+    }
+
+    return rv;
+}
+
+/******************************************************************************/
+void
+timers_oneshot_update_poll(struct timers_oneshot *timer, unsigned int now,
+                           int *timeout)
+{
+    if (timer != NULL && timeout != NULL)
+    {
+        int remaining = timers_oneshot_get_remaining(timer, now);
+        if (*timeout < 0 || *timeout > remaining)
+        {
+            *timeout = remaining;
+        }
+    }
+}