A more efficient implementation for OpenVMS using event flags, contributed

by Colin Blakes <colin@theblakes.com>.

nsprpub/pr/src/io/prpolevt.c

@@ -39,6 +39,85 @@
 #include "prerror.h"
 #include "prlog.h"
 
+#ifdef VMS
+
+/*
+ * On OpenVMS we use an event flag instead of a pipe or a socket since
+ * event flags are much more efficient on OpenVMS.
+ */
+#include "pprio.h"
+#include <lib$routines.h>
+#include <starlet.h>
+#include <stsdef.h>
+
+PR_IMPLEMENT(PRFileDesc *) PR_NewPollableEvent(void)
+{
+    unsigned int status;
+    int flag = -1;
+    PRFileDesc *event;
+
+    /*
+    ** Allocate an event flag and clear it.
+    */
+    status = lib$get_ef(&flag);
+    if ((!$VMS_STATUS_SUCCESS(status)) || (flag == -1)) {
+        PR_SetError(PR_INSUFFICIENT_RESOURCES_ERROR, status);
+        return NULL;
+    }
+    sys$clref(flag);
+
+    /*
+    ** Give NSPR the event flag's negative value. We do this because our
+    ** select interprets a negative fd as an event flag rather than a
+    ** regular file fd.
+    */
+    event = PR_CreateSocketPollFd(-flag);
+    if (NULL == event) {
+        lib$free_ef(&flag);
+        return NULL;
+    }
+
+    return event;
+}
+
+PR_IMPLEMENT(PRStatus) PR_DestroyPollableEvent(PRFileDesc *event)
+{
+    int flag = -PR_FileDesc2NativeHandle(event);
+    PR_DestroySocketPollFd(event);
+    lib$free_ef(&flag);
+    return PR_SUCCESS;
+}
+
+PR_IMPLEMENT(PRStatus) PR_SetPollableEvent(PRFileDesc *event)
+{
+    /*
+    ** Just set the event flag.
+    */
+    unsigned int status;
+    status = sys$setef(-PR_FileDesc2NativeHandle(event));
+    if (!$VMS_STATUS_SUCCESS(status)) {
+        PR_SetError(PR_INVALID_ARGUMENT_ERROR, status);
+        return PR_FAILURE;
+    }
+    return PR_SUCCESS;
+}
+
+PR_IMPLEMENT(PRStatus) PR_WaitForPollableEvent(PRFileDesc *event)
+{
+    /*
+    ** Just clear the event flag.
+    */
+    unsigned int status;
+    status = sys$clref(-PR_FileDesc2NativeHandle(event));
+    if (!$VMS_STATUS_SUCCESS(status)) {
+        PR_SetError(PR_INVALID_ARGUMENT_ERROR, status);
+        return PR_FAILURE;
+    }
+    return PR_SUCCESS;
+}
+
+#else /* VMS */
+
 /*
  * These internal functions are declared in primpl.h,
  * but we can't include primpl.h because the definition
@@ -121,7 +200,7 @@ static PRStatus PR_CALLBACK _pr_PolEvtInit(void)
     return PR_SUCCESS;
 }
 
-#if !defined(XP_UNIX) || defined(VMS)
+#if !defined(XP_UNIX)
 #define USE_TCP_SOCKETPAIR
 #endif
 
@@ -230,3 +309,5 @@ PR_IMPLEMENT(PRStatus) PR_WaitForPollableEvent(PRFileDesc *event)
 
     return PR_SUCCESS;
 }
+
+#endif /* VMS */