Add a non-blocking mode to the log reader.

git-svn-id: http://www.varnish-cache.org/svn/trunk/varnish-cache@1025 d4fa192b-c00b-0410-8231-f00ffab90ce4

include/varnishapi.h

@@ -22,6 +22,7 @@ struct VSL_data;
 struct VSL_data *VSL_New(void);
 void VSL_Select(struct VSL_data *vd, unsigned tag);
 int VSL_OpenLog(struct VSL_data *vd);
+void VSL_NonBlocking(struct VSL_data *vd, int nb);
 int VSL_Dispatch(struct VSL_data *vd, vsl_handler *func, void *priv);
 int VSL_NextLog(struct VSL_data *lh, unsigned char **pp);
 int VSL_Arg(struct VSL_data *vd, int arg, const char *opt);

lib/libvarnishapi/shmlog.c

@@ -42,6 +42,7 @@ struct VSL_data {
 
 	unsigned		flags;
 #define F_SEEN_IX		(1 << 0)
+#define F_NON_BLOCKING		(1 << 1)
 
 	unsigned char		map[NFD];
 #define M_CLIENT		(1 << 0)
@@ -165,6 +166,17 @@ VSL_OpenLog(struct VSL_data *vd)
 
 /*--------------------------------------------------------------------*/
 
+void
+VSL_NonBlocking(struct VSL_data *vd, int nb)
+{
+	if (nb)
+		vd->flags |= F_NON_BLOCKING;
+	else
+		vd->flags &= ~F_NON_BLOCKING;
+}
+
+/*--------------------------------------------------------------------*/
+
 static int
 vsl_nextlog(struct VSL_data *vd, unsigned char **pp)
 {
@@ -191,6 +203,8 @@ vsl_nextlog(struct VSL_data *vd, unsigned char **pp)
 			continue;
 		}
 		if (*p == SLT_ENDMARKER) {
+			if (vd->flags & F_NON_BLOCKING)
+				return (-1);
 			w += SLEEP_USEC;
 			usleep(SLEEP_USEC);
 			continue;