first version in which the constructor has arguments to configure

the underlying hash, and getter methods return the config values

src/tests/b01.vtc

@@ -26,7 +26,7 @@ varnish v1 -vcl+backend {
         import std;
 
         sub vcl_init {
-        	new inst = vtstor.vtstor();
+        	new inst = vtstor.vtstor(0, 0, 0, 0);
         }
 
         sub vcl_recv {

src/tests/b02.vtc

+varnishtest "vtstor-vmod: test the contructor"
+
+server s1 {} -start
+
+varnish v1 -vcl+backend {
+	import vtstor from "${vmod_topbuild}/src/.libs/libvmod_vtstor.so";
+        import std;
+
+        sub vcl_init {
+        	new zero = vtstor.vtstor(0, 0, 0, 0);
+        }
+
+        sub vcl_recv {
+            return(synth(200, "OK"));
+        }
+
+        sub vcl_synth {
+            set resp.http.Zero-Buckets = zero.buckets();
+            set resp.http.Zero-Timeout = zero.timeout();
+            set resp.http.Zero-Keymax = zero.key_max();
+            set resp.http.Zero-Valmax = zero.value_max();
+        }
+} -start
+
+client c1 {
+	txreq
+	rxresp
+	expect resp.status == 200
+        expect resp.http.Zero-Buckets == "1024"
+        expect resp.http.Zero-Timeout == "60"
+        expect resp.http.Zero-Keymax == "64"
+        expect resp.http.Zero-Valmax == "4096"
+} -run

src/vmod_vtstor.c

@@ -61,8 +61,9 @@ selecthttp(VRT_CTX, enum gethdr_e where)
 }
 
 VCL_VOID __match_proto__(td_vmod_vtstor__init)
-vmod_vtstor__init(VRT_CTX,
-    struct vmod_vtstor_vtstor **vmip, const char *vcl_name)
+vmod_vtstor__init(VRT_CTX, struct vmod_vtstor_vtstor **vmip,
+		  const char *vcl_name, VCL_INT nbuckets,
+		  VCL_INT timeout, VCL_INT keymax, VCL_INT valmax)
 {
 	struct vmod_vtstor_vtstor *vmi;
 	CHECK_OBJ_NOTNULL(ctx, VRT_CTX_MAGIC);
@@ -75,10 +76,19 @@ vmod_vtstor__init(VRT_CTX,
 	vmi->hash = vtstor_hash_sha256;
 	vmi->alloc = vtstor_alloc;
 	vmi->dealloc = vtstor_dealloc;
-	vmi->buckets = 1024;
-	vmi->timeout = 60;
-	vmi->key_max = 64;
-	vmi->value_max = 4096;
+
+#define CONFIG(f,d,v) do {			\
+		vmi->f = (d);			\
+		if ((v) > 0)			\
+			vmi->f = (v);		\
+	} while (0)
+
+	CONFIG(buckets, DEFAULT_NBUCKETS, nbuckets);
+	CONFIG(timeout, DEFAULT_TIMEOUT, timeout);
+	CONFIG(key_max, DEFAULT_KEYMAX, keymax);
+	CONFIG(value_max, DEFAULT_VALMAX,  valmax);
+#undef CONFIG
+
 	vmi->map = vtstor_init(vmi);
 	*vmip = vmi;
 	CHECK_OBJ_NOTNULL(*vmip, VMOD_VTSTOR_VTSTOR_MAGIC);
@@ -156,6 +166,42 @@ vmod_vtstor_delete(VRT_CTX, struct vmod_vtstor_vtstor *vmi, VCL_HEADER hdr)
 	}
 }
 
+VCL_INT __match_proto__(td_vmod_vtstor_buckets)
+vmod_vtstor_buckets(VRT_CTX, struct vmod_vtstor_vtstor *vmi)
+{
+	(void) ctx;
+	CHECK_OBJ_NOTNULL(vmi, VMOD_VTSTOR_VTSTOR_MAGIC);
+
+	return vmi->buckets;
+}
+
+VCL_INT __match_proto__(td_vmod_vtstor_timeout)
+vmod_vtstor_timeout(VRT_CTX, struct vmod_vtstor_vtstor *vmi)
+{
+	(void) ctx;
+	CHECK_OBJ_NOTNULL(vmi, VMOD_VTSTOR_VTSTOR_MAGIC);
+
+	return vmi->timeout;
+}
+
+VCL_INT __match_proto__(td_vmod_vtstor_keymax)
+vmod_vtstor_key_max(VRT_CTX, struct vmod_vtstor_vtstor *vmi)
+{
+	(void) ctx;
+	CHECK_OBJ_NOTNULL(vmi, VMOD_VTSTOR_VTSTOR_MAGIC);
+
+	return vmi->key_max;
+}
+
+VCL_INT __match_proto__(td_vmod_vtstor_value_max)
+vmod_vtstor_value_max(VRT_CTX, struct vmod_vtstor_vtstor *vmi)
+{
+	(void) ctx;
+	CHECK_OBJ_NOTNULL(vmi, VMOD_VTSTOR_VTSTOR_MAGIC);
+
+	return vmi->value_max;
+}
+
 VCL_STRING __match_proto__(td_vmod_vxid)
 vmod_vxid(VRT_CTX)
 {

src/vmod_vtstor.vcc

@@ -28,10 +28,14 @@
 
 $Module vtstor 3
 
-$Object vtstor()
+$Object vtstor(INT, INT, INT, INT)
 $Method VOID .store(STRING, HEADER)
 $Method STRING .get(HEADER)
 $Method VOID .delete(HEADER)
+$Method INT .buckets()
+$Method INT .timeout()
+$Method INT .key_max()
+$Method INT .value_max()
 
 $Function STRING vxid()
 

src/vtstor.h

@@ -33,6 +33,11 @@
 
 #include "vcc_if.h"
 
+#define DEFAULT_NBUCKETS 1024
+#define DEFAULT_TIMEOUT 60
+#define DEFAULT_KEYMAX 64
+#define DEFAULT_VALMAX 4096
+
 struct vmod_vtstor_vtstor;
 
 typedef size_t (*malloc_func)(struct vmod_vtstor_vtstor *, size_t, char **);