Adding upstream version 14.5.upstream/14.5upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 121 insertions, 0 deletions

diff --git a/src/backend/port/win32/timer.c b/src/backend/port/win32/timer.c
new file mode 100644
index 0000000..53fdae9
--- /dev/null
+++ b/src/backend/port/win32/timer.c
@@ -0,0 +1,121 @@
+/*-------------------------------------------------------------------------
+ *
+ * timer.c
+ *	  Microsoft Windows Win32 Timer Implementation
+ *
+ *	  Limitations of this implementation:
+ *
+ *	  - Does not support interval timer (value->it_interval)
+ *	  - Only supports ITIMER_REAL
+ *
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *	  src/backend/port/win32/timer.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+
+/* Communication area for inter-thread communication */
+typedef struct timerCA
+{
+	struct itimerval value;
+	HANDLE		event;
+	CRITICAL_SECTION crit_sec;
+} timerCA;
+
+static timerCA timerCommArea;
+static HANDLE timerThreadHandle = INVALID_HANDLE_VALUE;
+
+
+/* Timer management thread */
+static DWORD WINAPI
+pg_timer_thread(LPVOID param)
+{
+	DWORD		waittime;
+
+	Assert(param == NULL);
+
+	waittime = INFINITE;
+
+	for (;;)
+	{
+		int			r;
+
+		r = WaitForSingleObjectEx(timerCommArea.event, waittime, FALSE);
+		if (r == WAIT_OBJECT_0)
+		{
+			/* Event signaled from main thread, change the timer */
+			EnterCriticalSection(&timerCommArea.crit_sec);
+			if (timerCommArea.value.it_value.tv_sec == 0 &&
+				timerCommArea.value.it_value.tv_usec == 0)
+				waittime = INFINITE;	/* Cancel the interrupt */
+			else
+			{
+				/* WaitForSingleObjectEx() uses milliseconds, round up */
+				waittime = (timerCommArea.value.it_value.tv_usec + 999) / 1000 +
+					timerCommArea.value.it_value.tv_sec * 1000;
+			}
+			ResetEvent(timerCommArea.event);
+			LeaveCriticalSection(&timerCommArea.crit_sec);
+		}
+		else if (r == WAIT_TIMEOUT)
+		{
+			/* Timeout expired, signal SIGALRM and turn it off */
+			pg_queue_signal(SIGALRM);
+			waittime = INFINITE;
+		}
+		else
+		{
+			/* Should never happen */
+			Assert(false);
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * Win32 setitimer emulation by creating a persistent thread
+ * to handle the timer setting and notification upon timeout.
+ */
+int
+setitimer(int which, const struct itimerval *value, struct itimerval *ovalue)
+{
+	Assert(value != NULL);
+	Assert(value->it_interval.tv_sec == 0 && value->it_interval.tv_usec == 0);
+	Assert(which == ITIMER_REAL);
+
+	if (timerThreadHandle == INVALID_HANDLE_VALUE)
+	{
+		/* First call in this backend, create event and the timer thread */
+		timerCommArea.event = CreateEvent(NULL, TRUE, FALSE, NULL);
+		if (timerCommArea.event == NULL)
+			ereport(FATAL,
+					(errmsg_internal("could not create timer event: error code %lu",
+									 GetLastError())));
+
+		MemSet(&timerCommArea.value, 0, sizeof(struct itimerval));
+
+		InitializeCriticalSection(&timerCommArea.crit_sec);
+
+		timerThreadHandle = CreateThread(NULL, 0, pg_timer_thread, NULL, 0, NULL);
+		if (timerThreadHandle == INVALID_HANDLE_VALUE)
+			ereport(FATAL,
+					(errmsg_internal("could not create timer thread: error code %lu",
+									 GetLastError())));
+	}
+
+	/* Request the timer thread to change settings */
+	EnterCriticalSection(&timerCommArea.crit_sec);
+	if (ovalue)
+		*ovalue = timerCommArea.value;
+	timerCommArea.value = *value;
+	LeaveCriticalSection(&timerCommArea.crit_sec);
+	SetEvent(timerCommArea.event);
+
+	return 0;
+}