Add obj.hits VRT variable which counts how many *previous* hits

this object has seen.

Idea for prefetching being used as workaround for #310 



git-svn-id: http://www.varnish-cache.org/svn/trunk/varnish-cache@3166 d4fa192b-c00b-0410-8231-f00ffab90ce4

bin/varnishd/cache.h

@@ -285,6 +285,8 @@ struct object {
 	/* Prefetch */
 	struct object		*parent;
 	struct object		*child;
+
+	int			hits;
 };
 
 struct objhead {

bin/varnishd/cache_hash.c

@@ -58,6 +58,7 @@
 #include <stdlib.h>
 #include <math.h>
 #include <string.h>
+#include <limits.h>
 #include <sys/types.h>
 #include <fcntl.h>
 
@@ -253,6 +254,8 @@ HSH_Lookup(struct sess *sp)
 	if (o != NULL) {
 		/* We found an object we like */
 		o->refcnt++;
+		if (o->hits < INT_MAX)
+			o->hits++;
 		UNLOCK(&oh->mtx);
 		if (params->log_hash)
 			WSP(sp, SLT_Hash, "%s", oh->hash);

bin/varnishd/cache_vrt.c

@@ -552,6 +552,15 @@ VRT_r_now(const struct sess *sp)
 	return (TIM_real());
 }
 
+int
+VRT_r_obj_hits(const struct sess *sp)
+{
+
+	CHECK_OBJ_NOTNULL(sp, SESS_MAGIC);
+	CHECK_OBJ_NOTNULL(sp->obj, OBJECT_MAGIC);	/* XXX */
+	return (sp->obj->hits);
+}
+
 double
 VRT_r_obj_lastuse(const struct sess *sp)
 {

bin/varnishtest/tests/c00005.vtc

@@ -11,7 +11,7 @@ server s1 {
 	txresp -body "2222\n"
 } -start
 
-varnish v1 -vcl+backend {
+varnish v1 -arg "-p vcl_trace=on" -vcl+backend {
 	acl acl1 {
 		"localhost";
 	}

bin/varnishtest/tests/v00013.vtc

+# $Id$
+
+test "Check obj.hits"
+
+server s1 {
+	rxreq
+	expect req.url == "/"
+	txresp -body "slash"
+	rxreq
+	expect req.url == "/foo"
+	txresp -body "foo"
+} -start
+
+varnish v1 -vcl+backend {
+
+	sub vcl_deliver {
+		set resp.http.foo = obj.hits;
+	}
+} -start
+
+client c1 {
+	txreq
+	rxresp
+	expect resp.status == 200
+	expect resp.http.foo == 0
+
+	txreq
+	rxresp
+	expect resp.status == 200
+	expect resp.http.foo == 1
+
+	txreq -url /foo
+	rxresp
+	expect resp.status == 200
+	expect resp.http.foo == 0
+
+	txreq
+	rxresp
+	expect resp.status == 200
+	expect resp.http.foo == 2
+} -run 
+

include/vrt_obj.h

@@ -34,6 +34,7 @@ int VRT_r_obj_status(const struct sess *);
 void VRT_l_obj_status(const struct sess *, int);
 const char * VRT_r_obj_response(const struct sess *);
 void VRT_l_obj_response(const struct sess *, const char *, ...);
+int VRT_r_obj_hits(const struct sess *);
 unsigned VRT_r_obj_cacheable(const struct sess *);
 void VRT_l_obj_cacheable(const struct sess *, unsigned);
 double VRT_r_obj_ttl(const struct sess *);

lib/libvcl/vcc_gen_obj.tcl

@@ -144,6 +144,11 @@ set spobj {
 	{                             fetch                         error}
 	"const struct sess *"
     }
+    { obj.hits
+	RO INT
+	{			  hit fetch deliver                      }
+	"const struct sess *"
+    }
     { obj.http.
 	RW HDR_OBJ
 	{                         hit fetch 			    error}

lib/libvcl/vcc_obj.c

@@ -144,6 +144,13 @@ struct var vcc_vars[] = {
 	    0,
 	    VCL_MET_FETCH | VCL_MET_ERROR
 	},
+	{ "obj.hits", INT, 8,
+	    "VRT_r_obj_hits(sp)",
+	    NULL,
+	    V_RO,
+	    0,
+	    VCL_MET_HIT | VCL_MET_FETCH | VCL_MET_DELIVER
+	},
 	{ "obj.http.", HEADER, 9,
 	    "VRT_r_obj_http_(sp)",
 	    "VRT_l_obj_http_(sp, ",