Reorganisation of the source tree

[ghc-hetmet.git] / rts / win32 / Ticker.c

diff --git a/rts/win32/Ticker.c b/rts/win32/Ticker.c
new file mode 100644 (file)
index 0000000..ab791d8
--- /dev/null
+++ b/rts/win32/Ticker.c
@@ -0,0 +1,124 @@
+/*
+ * RTS periodic timers.
+ * 
+ */
+#include "Rts.h"
+#include "Timer.h"
+#include "Ticker.h"
+#include <windows.h>
+#include <stdio.h>
+#include <process.h>
+#include "OSThreads.h"
+
+/*
+ * Provide a timer service for the RTS, periodically
+ * notifying it that a number of 'ticks' has passed.
+ *
+ */
+
+/* To signal shutdown of the timer service, we use a local
+ * event which the timer thread listens to (and stopVirtTimer()
+ * signals.)
+ */
+static HANDLE hStopEvent = INVALID_HANDLE_VALUE;
+static HANDLE tickThread = INVALID_HANDLE_VALUE;
+
+static TickProc tickProc = NULL;
+
+/*
+ * Ticking is done by a separate thread which periodically
+ * wakes up to handle a tick.
+ *
+ * This is the portable way of providing a timer service under
+ * Win32; features like waitable timers or timer queues are only
+ * supported by a subset of the Win32 platforms (notably not
+ * under Win9x.)
+ *
+ */
+static
+unsigned
+WINAPI
+TimerProc(PVOID param)
+{
+  int ms = (int)param;
+  DWORD waitRes;
+  
+  /* interpret a < 0 timeout period as 'instantaneous' */ 
+ if (ms < 0) ms = 0;
+
+  while (1) {
+    waitRes = WaitForSingleObject(hStopEvent, ms);
+    
+    switch (waitRes) {
+    case WAIT_OBJECT_0:
+      /* event has become signalled */
+      tickProc = NULL;
+      CloseHandle(hStopEvent);
+      return 0;
+    case WAIT_TIMEOUT:
+      /* tick */
+      tickProc(0);
+      break;
+    case WAIT_FAILED: {
+       DWORD dw = GetLastError();
+       fprintf(stderr, "TimerProc: wait failed -- error code: %lu\n", dw); fflush(stderr);
+       break; 
+    }
+    default:
+      fprintf(stderr, "TimerProc: unexpected result %lu\n", waitRes); fflush(stderr);
+      break;
+    }
+  }
+  return 0;
+}
+
+
+int
+startTicker(nat ms, TickProc handle_tick)
+{
+  unsigned threadId;
+  /* 'hStopEvent' is a manual-reset event that's signalled upon
+   * shutdown of timer service (=> timer thread.)
+   */
+  hStopEvent = CreateEvent ( NULL,
+                            TRUE,
+                            FALSE,
+                            NULL);
+  if (hStopEvent == INVALID_HANDLE_VALUE) {
+    return 0;
+  }
+  tickProc = handle_tick;
+  tickThread = (HANDLE)(long)_beginthreadex( NULL,
+                              0,
+                              TimerProc,
+                              (LPVOID)ms,
+                              0,
+                              &threadId);
+  return (tickThread != 0);
+}
+
+int
+stopTicker(void)
+{
+    // We must wait for the ticker thread to terminate, since if we
+    // are in a DLL that is about to be unloaded, the ticker thread
+    // cannot be allowed to return to a missing DLL.
+
+    if (hStopEvent != INVALID_HANDLE_VALUE && 
+       tickThread != INVALID_HANDLE_VALUE) {
+       DWORD exitCode;
+       SetEvent(hStopEvent);
+       while (1) {
+           WaitForSingleObject(tickThread, 20);
+           if (!GetExitCodeThread(tickThread, &exitCode)) {
+               return 1;
+           }
+           if (exitCode != STILL_ACTIVE) {
+               tickThread = INVALID_HANDLE_VALUE;
+               return 0;
+           }
+           TerminateThread(tickThread, 0);
+       }
+    }
+    return 0;
+}