Add the .backend() method.

set objects now have bitmaps internally to keep track of which data
types have been added for each element.

README.rst

@@ -25,6 +25,7 @@ CONTENTS
 
 * :ref:`obj_set`
 * :ref:`func_set.add`
+* :ref:`func_set.backend`
 * :ref:`func_set.debug`
 * :ref:`func_set.element`
 * :ref:`func_set.hasprefix`
@@ -195,6 +196,27 @@ Example::
   }
 
 
+.. _func_set.backend:
+
+BACKEND xset.backend(INT n, ENUM select)
+----------------------------------------
+
+::
+
+      BACKEND xset.backend(
+            INT n=0,
+            ENUM {UNIQUE, EXACT, FIRST, LAST, SHORTEST, LONGEST} select=UNIQUE
+      )
+
+Returns ...
+
+Example::
+
+  if (myset.hasprefix(req.url)) {
+     # ...
+  }
+
+
 .. _func_set.debug:
 
 STRING xset.debug()

src/tests/backend.vtc

+# looks like -*- vcl -*-
+
+varnishtest "element() method"
+
+varnish v1 -vcl {
+	import ${vmod_selector};
+	backend b1 { .host = "${bad_ip}"; }
+	backend b2 { .host = "${bad_ip}"; }
+	backend b3 { .host = "${bad_ip}"; }
+	backend b4 { .host = "${bad_ip}"; }
+	backend b5 { .host = "${bad_ip}"; }
+
+	sub vcl_init {
+		new s = selector.set();
+		s.add("foo", backend=b1);
+		s.add("bar", backend=b2);
+		s.add("baz", backend=b3);
+		s.add("quux", backend=b4);
+		s.add("foobar", backend=b5);
+	}
+
+	sub vcl_recv {
+		return (synth(200));
+	}
+
+	sub vcl_synth {
+		set resp.http.N-1 = s.backend(1);
+		set resp.http.N-2 = s.backend(2);
+		set resp.http.N-3 = s.backend(3);
+		set resp.http.N-4 = s.backend(4);
+		set resp.http.N-5 = s.backend(5);
+
+		set resp.http.N--1 = s.backend(-1);
+		set resp.http.N-0 = s.backend(0);
+		set resp.http.N-6 = s.backend(6);
+
+		if (s.match(req.http.Word)) {
+			set resp.http.Backend = s.backend();
+			set resp.http.Backend-Unique = s.backend(select=UNIQUE);
+			set resp.http.Backend-Exact = s.backend(select=EXACT);
+			set resp.http.Backend-First = s.backend(select=FIRST);
+			set resp.http.Backend-Last = s.backend(select=LAST);
+			set resp.http.Backend-Shortest
+			    = s.backend(select=SHORTEST);
+			set resp.http.Backend-Longest
+			    = s.backend(select=LONGEST);
+		}
+		return (deliver);
+	}
+} -start
+
+client c1 {
+	txreq
+	rxresp
+	expect resp.status == 200
+	expect resp.http.N-1 == "b1"
+	expect resp.http.N-2 == "b2"
+	expect resp.http.N-3 == "b3"
+	expect resp.http.N-4 == "b4"
+	expect resp.http.N-5 == "b5"
+
+	expect resp.http.N--1 == ""
+	expect resp.http.N-0 == ""
+	expect resp.http.N-6 == ""
+
+	txreq -hdr "Word: foo"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.Backend == "b1"
+	expect resp.http.Backend-Unique == resp.http.Backend
+	expect resp.http.Backend-Exact == resp.http.Backend
+	expect resp.http.Backend-First == "b1"
+	expect resp.http.Backend-Last == "b1"
+	expect resp.http.Backend-Shortest == "b1"
+	expect resp.http.Backend-Longest == "b1"
+
+	txreq -hdr "Word: bar"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.Backend == "b2"
+	expect resp.http.Backend-Unique == resp.http.Backend
+	expect resp.http.Backend-Exact == resp.http.Backend
+	expect resp.http.Backend-First == "b2"
+	expect resp.http.Backend-Last == "b2"
+	expect resp.http.Backend-Shortest == "b2"
+	expect resp.http.Backend-Longest == "b2"
+
+	txreq -hdr "Word: baz"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.Backend == "b3"
+	expect resp.http.Backend-Unique == resp.http.Backend
+	expect resp.http.Backend-Exact == resp.http.Backend
+	expect resp.http.Backend-First == "b3"
+	expect resp.http.Backend-Last == "b3"
+	expect resp.http.Backend-Shortest == "b3"
+	expect resp.http.Backend-Longest == "b3"
+
+	txreq -hdr "Word: quux"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.Backend == "b4"
+	expect resp.http.Backend-Unique == resp.http.Backend
+	expect resp.http.Backend-Exact == resp.http.Backend
+	expect resp.http.Backend-First == "b4"
+	expect resp.http.Backend-Last == "b4"
+	expect resp.http.Backend-Shortest == "b4"
+	expect resp.http.Backend-Longest == "b4"
+
+	txreq -hdr "Word: foobar"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.Backend == "b5"
+	expect resp.http.Backend-Unique == resp.http.Backend
+	expect resp.http.Backend-Exact == resp.http.Backend
+	expect resp.http.Backend-First == "b5"
+	expect resp.http.Backend-Last == "b5"
+	expect resp.http.Backend-Shortest == "b5"
+	expect resp.http.Backend-Longest == "b5"
+} -run
+
+logexpect l1 -v v1 -d 1 -g vxid -q "VCL_Error" {
+	expect 0 * Begin req
+	expect * = VCL_Error {^vmod selector error: s\.backend\(\) called without prior match$}
+	expect * = VCL_Error {^vmod selector error: s\.backend\(\) called without prior match$}
+	expect * = VCL_Error {^vmod selector error: s\.backend\(6\): set has 5 elements$}
+	expect * = End
+} -run
+
+varnish v1 -vcl {
+	import ${vmod_selector};
+	backend b1 { .host = "${bad_ip}"; }
+	backend b2 { .host = "${bad_ip}"; }
+	backend b3 { .host = "${bad_ip}"; }
+	backend b4 { .host = "${bad_ip}"; }
+
+	sub vcl_init {
+		new s = selector.set();
+		s.add("foobarbazquux", backend=b1);
+		s.add("foobarbaz", backend=b2);
+		s.add("foobar", backend=b3);
+		s.add("foo", backend=b4);
+	}
+
+	sub vcl_recv {
+		return (synth(200));
+	}
+
+	sub vcl_synth {
+		if (s.hasprefix(req.http.Word)) {
+			set resp.http.Backend = s.backend();
+			set resp.http.Backend-Unique = s.backend(select=UNIQUE);
+			set resp.http.Backend-Exact = s.backend(select=EXACT);
+			set resp.http.Backend-First = s.backend(select=FIRST);
+			set resp.http.Backend-Last = s.backend(select=LAST);
+			set resp.http.Backend-Shortest
+			    = s.backend(select=SHORTEST);
+			set resp.http.Backend-Longest
+			    = s.backend(select=LONGEST);
+		}
+		return (deliver);
+	}
+}
+
+logexpect l1 -v v1 -d 0 -g vxid -q "VCL_Error" {
+	expect * 1009 Begin req
+	expect * = VCL_Error {^vmod selector error: s\.backend\(select=UNIQUE\): 2 elements were matched$}
+	expect * = VCL_Error {^vmod selector error: s\.backend\(select=UNIQUE\): 2 elements were matched$}
+	expect * = End
+
+	expect 0 * Begin req
+	expect * = VCL_Error {^vmod selector error: s\.backend\(select=UNIQUE\): 3 elements were matched$}
+	expect * = VCL_Error {^vmod selector error: s\.backend\(select=UNIQUE\): 3 elements were matched$}
+	expect * = End
+
+	expect 0 * Begin req
+	expect * = VCL_Error {^vmod selector error: s\.backend\(select=UNIQUE\): 4 elements were matched$}
+	expect * = VCL_Error {^vmod selector error: s\.backend\(select=UNIQUE\): 4 elements were matched$}
+	expect * = End
+
+	expect 0 * Begin req
+	expect * = VCL_Error {^vmod selector error: s\.backend\(select=UNIQUE\): 2 elements were matched$}
+	expect * = VCL_Error {^vmod selector error: s\.backend\(select=UNIQUE\): 2 elements were matched$}
+	expect * = VCL_Error {^vmod selector error: s\.backend\(select=EXACT\): no element matched exactly$}
+	expect * = End
+} -start
+
+client c1 {
+	txreq -hdr "Word: foo"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.Backend == "b4"
+	expect resp.http.Backend-Unique == "b4"
+	expect resp.http.Backend-Exact == "b4"
+	expect resp.http.Backend-First == "b4"
+	expect resp.http.Backend-Last == "b4"
+	expect resp.http.Backend-Shortest == "b4"
+	expect resp.http.Backend-Longest == "b4"
+
+	txreq -hdr "Word: foobar"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.Backend == ""
+	expect resp.http.Backend-Unique == ""
+	expect resp.http.Backend-Exact == "b3"
+	expect resp.http.Backend-First == "b3"
+	expect resp.http.Backend-Last == "b4"
+	expect resp.http.Backend-Shortest == "b4"
+	expect resp.http.Backend-Longest == "b3"
+
+	txreq -hdr "Word: foobarbaz"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.Backend == ""
+	expect resp.http.Backend-Unique == ""
+	expect resp.http.Backend-Exact == "b2"
+	expect resp.http.Backend-First == "b2"
+	expect resp.http.Backend-Last == "b4"
+	expect resp.http.Backend-Shortest == "b4"
+	expect resp.http.Backend-Longest == "b2"
+
+	txreq -hdr "Word: foobarbazquux"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.Backend == ""
+	expect resp.http.Backend-Unique == ""
+	expect resp.http.Backend-Exact == "b1"
+	expect resp.http.Backend-First == "b1"
+	expect resp.http.Backend-Last == "b4"
+	expect resp.http.Backend-Shortest == "b4"
+	expect resp.http.Backend-Longest == "b1"
+
+	txreq -hdr "Word: foobarb"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.Backend == ""
+	expect resp.http.Backend-Unique == ""
+	expect resp.http.Backend-Exact == ""
+	expect resp.http.Backend-First == "b3"
+	expect resp.http.Backend-Last == "b4"
+	expect resp.http.Backend-Shortest == "b4"
+	expect resp.http.Backend-Longest == "b3"
+} -run
+
+logexpect l1 -wait
+
+varnish v1 -vcl {
+	import ${vmod_selector};
+	backend b { .host = "${bad_ip}"; }
+
+	sub vcl_init {
+		new s = selector.set();
+		s.add("foo", backend=b);
+		s.add("bar");
+	}
+
+	sub vcl_recv {
+		return (synth(200));
+	}
+
+	sub vcl_synth {
+		if (s.match(req.http.Word)) {
+			set resp.http.Backend = s.backend();
+		}
+		return (deliver);
+	}
+}
+
+logexpect l1 -v v1 -d 0 -g vxid -q "VCL_Error" {
+	expect 0 * Begin req
+	expect * = VCL_Error {^vmod selector error: s\.backend\(\): backend not added for element 2$}
+	expect * = End
+} -start
+
+client c1 {
+	txreq -hdr "Word: foo"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.Backend == "b"
+
+	txreq -hdr "Word: bar"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.Backend == ""
+} -run
+
+logexpect l1 -wait

src/vmod_selector.c

@@ -38,6 +38,7 @@
 #include "cache/cache.h"
 #include "vcl.h"
 #include "vre.h"
+#include "vbm.h"
 #include "cache/cache_director.h"
 
 #include "vcc_if.h"
@@ -61,6 +62,19 @@ struct entry {
 	vre_t		*re;
 };
 
+enum bitmap_e {
+	STRING = 0,
+	BACKEND,
+	REGEX,
+	__MAX_BITMAP,
+};
+
+struct bitmaps {
+	unsigned	magic;
+#define VMOD_SELECTOR_BITMAPS_MAGIC 0x5b17093f
+	struct vbitmap	*bitmaps[__MAX_BITMAP];
+};
+
 struct vmod_selector_set {
 	unsigned	magic;
 #define VMOD_SELECTOR_SET_MAGIC 0x838979ef
@@ -69,6 +83,7 @@ struct vmod_selector_set {
 	char		**lomembers;
 	struct pt_y	*origo;
 	char		*vcl_name;
+	struct bitmaps	*bitmaps;
 	unsigned	nmembers;
 	unsigned	nentries;
 	VCL_BOOL	case_sensitive;
@@ -106,6 +121,14 @@ vmod_set__init(VRT_CTX, struct vmod_selector_set **setp, const char *vcl_name,
 	set->vcl_name = strdup(vcl_name);
 	AN(set->vcl_name);
 	set->case_sensitive = case_sensitive;
+
+	ALLOC_OBJ(set->bitmaps, VMOD_SELECTOR_BITMAPS_MAGIC);
+	AN(set->bitmaps);
+	for (int i = 0; i < __MAX_BITMAP; i++) {
+		set->bitmaps->bitmaps[i] = vbit_new(0);
+		AN(set->bitmaps->bitmaps[i]);
+	}
+
 	AZ(set->table);
 	AZ(set->members);
 	AZ(set->origo);
@@ -133,12 +156,37 @@ vmod_set__fini(struct vmod_selector_set **setp)
 			VRE_free(&entry->re);
 		FREE_OBJ(entry);
 	}
+	for (int i = 0; i < __MAX_BITMAP; i++)
+		vbit_destroy(set->bitmaps->bitmaps[i]);
+	FREE_OBJ(set->bitmaps);
+
 	free(set->members);
 	free(set->table);
 	free(set->vcl_name);
 	FREE_OBJ(set);
 }
 
+static inline void
+set_added(struct vmod_selector_set *set, unsigned idx, enum bitmap_e bitmap)
+{
+	CHECK_OBJ_NOTNULL(set, VMOD_SELECTOR_SET_MAGIC);
+	CHECK_OBJ_NOTNULL(set->bitmaps, VMOD_SELECTOR_BITMAPS_MAGIC);
+	AN(set->bitmaps->bitmaps[bitmap]);
+
+	vbit_set(set->bitmaps->bitmaps[bitmap], idx);
+}
+
+static inline int
+is_added(const struct vmod_selector_set *set, unsigned idx,
+	 enum bitmap_e bitmap)
+{
+	CHECK_OBJ_NOTNULL(set, VMOD_SELECTOR_SET_MAGIC);
+	CHECK_OBJ_NOTNULL(set->bitmaps, VMOD_SELECTOR_BITMAPS_MAGIC);
+	AN(set->bitmaps->bitmaps[bitmap]);
+
+	return (vbit_test(set->bitmaps->bitmaps[bitmap], idx));
+}
+
 VCL_VOID
 vmod_set_add(VRT_CTX, struct vmod_selector_set *set, VCL_STRING member,
 	     VCL_STRING string, VCL_STRING regex, VCL_BACKEND backend)
@@ -214,12 +262,18 @@ vmod_set_add(VRT_CTX, struct vmod_selector_set *set, VCL_STRING member,
 	AN(set->table);
 	ALLOC_OBJ(entry, VMOD_SELECTOR_ENTRY_MAGIC);
 	AN(entry);
-	if (string != NULL)
+	if (string != NULL) {
 		entry->string = strdup(string);
-	if (re != NULL)
+		set_added(set, n - 1, STRING);
+	}
+	if (re != NULL) {
 		entry->re = re;
-	if (backend != NULL)
+		set_added(set, n - 1, REGEX);
+	}
+	if (backend != NULL) {
 		entry->backend = backend;
+		set_added(set, n - 1, BACKEND);
+	}
 	set->table[n - 1] = entry;
 }
 
@@ -506,6 +560,41 @@ vmod_set_element(VRT_CTX, struct vmod_selector_set *set, VCL_INT n,
 	return (set->members[idx]);
 }
 
+static inline int
+check_added(VRT_CTX, const struct vmod_selector_set * const restrict set,
+	    unsigned idx, enum bitmap_e bitmap,
+	    const char * const restrict method,
+	    const char * const restrict type)
+{
+	if (!is_added(set, idx, bitmap)) {
+		VERR(ctx, "%s.%s(): %s not added for element %u", set->vcl_name,
+		     method, type, idx + 1);
+		return (0);
+	}
+	return (1);
+}
+
+VCL_BACKEND
+vmod_set_backend(VRT_CTX, struct vmod_selector_set *set, VCL_INT n,
+		 VCL_ENUM selects)
+{
+	unsigned idx;
+	VCL_BACKEND b;
+
+	CHECK_OBJ_NOTNULL(ctx, VRT_CTX_MAGIC);
+	CHECK_OBJ_NOTNULL(set, VMOD_SELECTOR_SET_MAGIC);
+
+	idx = get_idx(ctx, n, set, "backend", selects);
+	if (idx == UINT_MAX)
+		return (NULL);
+	if (!check_added(ctx, set, idx, BACKEND, "backend", "backend"))
+		return (NULL);
+
+	b = set->table[idx]->backend;
+	CHECK_OBJ_NOTNULL(b, DIRECTOR_MAGIC);
+	return (b);
+}
+
 VCL_STRING
 vmod_set_debug(VRT_CTX, struct vmod_selector_set *set)
 {

src/vmod_selector.vcc

@@ -111,6 +111,18 @@ $Method STRING .element(INT n=0,
 
 Returns ...
 
+Example::
+
+  if (myset.hasprefix(req.url)) {
+     # ...
+  }
+
+$Method BACKEND .backend(INT n=0,
+			 ENUM {UNIQUE, EXACT, FIRST, LAST, SHORTEST, LONGEST}
+			 select=UNIQUE)
+
+Returns ...
+
 Example::
 
   if (myset.hasprefix(req.url)) {