Add the .element() method.

README.rst

@@ -26,6 +26,7 @@ CONTENTS
 * :ref:`obj_set`
 * :ref:`func_set.add`
 * :ref:`func_set.debug`
+* :ref:`func_set.element`
 * :ref:`func_set.hasprefix`
 * :ref:`func_set.match`
 * :ref:`func_set.matched`
@@ -173,6 +174,27 @@ Example::
   }
 
 
+.. _func_set.element:
+
+STRING xset.element(INT n, ENUM select)
+---------------------------------------
+
+::
+
+      STRING xset.element(
+            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/element.vtc

+# looks like -*- vcl -*-
+
+varnishtest "element() method"
+
+varnish v1 -vcl {
+	import ${vmod_selector};
+	backend b { .host = "${bad_ip}"; }
+
+	sub vcl_init {
+		new s = selector.set();
+		s.add("foo");
+		s.add("bar");
+		s.add("baz");
+		s.add("quux");
+		s.add("foobar");
+	}
+
+	sub vcl_recv {
+		return (synth(200));
+	}
+
+	sub vcl_synth {
+		set resp.http.N-1 = s.element(1);
+		set resp.http.N-2 = s.element(2);
+		set resp.http.N-3 = s.element(3);
+		set resp.http.N-4 = s.element(4);
+		set resp.http.N-5 = s.element(5);
+
+		set resp.http.N--1 = s.element(-1);
+		set resp.http.N-0 = s.element(0);
+		set resp.http.N-6 = s.element(6);
+
+		if (s.match(req.http.Word)) {
+			set resp.http.Element = s.element();
+			set resp.http.Element-Unique = s.element(select=UNIQUE);
+			set resp.http.Element-Exact = s.element(select=EXACT);
+			set resp.http.Element-First = s.element(select=FIRST);
+			set resp.http.Element-Last = s.element(select=LAST);
+			set resp.http.Element-Shortest
+			    = s.element(select=SHORTEST);
+			set resp.http.Element-Longest
+			    = s.element(select=LONGEST);
+		}
+		return (deliver);
+	}
+} -start
+
+client c1 {
+	txreq
+	rxresp
+	expect resp.status == 200
+	expect resp.http.N-1 == "foo"
+	expect resp.http.N-2 == "bar"
+	expect resp.http.N-3 == "baz"
+	expect resp.http.N-4 == "quux"
+	expect resp.http.N-5 == "foobar"
+
+	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.Element == "foo"
+	expect resp.http.Element-Unique == resp.http.Element
+	expect resp.http.Element-Exact == resp.http.Element
+	expect resp.http.Element-First == "foo"
+	expect resp.http.Element-Last == "foo"
+	expect resp.http.Element-Shortest == "foo"
+	expect resp.http.Element-Longest == "foo"
+
+	txreq -hdr "Word: bar"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.Element == "bar"
+	expect resp.http.Element-Unique == resp.http.Element
+	expect resp.http.Element-Exact == resp.http.Element
+	expect resp.http.Element-First == "bar"
+	expect resp.http.Element-Last == "bar"
+	expect resp.http.Element-Shortest == "bar"
+	expect resp.http.Element-Longest == "bar"
+
+	txreq -hdr "Word: baz"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.Element == "baz"
+	expect resp.http.Element-Unique == resp.http.Element
+	expect resp.http.Element-Exact == resp.http.Element
+	expect resp.http.Element-First == "baz"
+	expect resp.http.Element-Last == "baz"
+	expect resp.http.Element-Shortest == "baz"
+	expect resp.http.Element-Longest == "baz"
+
+	txreq -hdr "Word: quux"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.Element == "quux"
+	expect resp.http.Element-Unique == resp.http.Element
+	expect resp.http.Element-Exact == resp.http.Element
+	expect resp.http.Element-First == "quux"
+	expect resp.http.Element-Last == "quux"
+	expect resp.http.Element-Shortest == "quux"
+	expect resp.http.Element-Longest == "quux"
+
+	txreq -hdr "Word: foobar"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.Element == "foobar"
+	expect resp.http.Element-Unique == resp.http.Element
+	expect resp.http.Element-Exact == resp.http.Element
+	expect resp.http.Element-First == "foobar"
+	expect resp.http.Element-Last == "foobar"
+	expect resp.http.Element-Shortest == "foobar"
+	expect resp.http.Element-Longest == "foobar"
+} -run
+
+logexpect l1 -v v1 -d 1 -g vxid -q "VCL_Error" {
+	expect 0 * Begin req
+	expect * = VCL_Error {^vmod selector error: s\.element\(\) called without prior match$}
+	expect * = VCL_Error {^vmod selector error: s\.element\(\) called without prior match$}
+	expect * = VCL_Error {^vmod selector error: s\.element\(6\): set has 5 elements$}
+	expect * = End
+} -run
+
+varnish v1 -vcl {
+	import ${vmod_selector};
+	backend b { .host = "${bad_ip}"; }
+
+	sub vcl_init {
+		new s = selector.set();
+		s.add("foobarbazquux");
+		s.add("foobarbaz");
+		s.add("foobar");
+		s.add("foo");
+	}
+
+	sub vcl_recv {
+		return (synth(200));
+	}
+
+	sub vcl_synth {
+		if (s.hasprefix(req.http.Word)) {
+			set resp.http.Element = s.element();
+			set resp.http.Element-Unique = s.element(select=UNIQUE);
+			set resp.http.Element-Exact = s.element(select=EXACT);
+			set resp.http.Element-First = s.element(select=FIRST);
+			set resp.http.Element-Last = s.element(select=LAST);
+			set resp.http.Element-Shortest
+			    = s.element(select=SHORTEST);
+			set resp.http.Element-Longest
+			    = s.element(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\.element\(select=UNIQUE\): 2 elements were matched$}
+	expect * = VCL_Error {^vmod selector error: s\.element\(select=UNIQUE\): 2 elements were matched$}
+	expect * = End
+
+	expect 0 * Begin req
+	expect * = VCL_Error {^vmod selector error: s\.element\(select=UNIQUE\): 3 elements were matched$}
+	expect * = VCL_Error {^vmod selector error: s\.element\(select=UNIQUE\): 3 elements were matched$}
+	expect * = End
+
+	expect 0 * Begin req
+	expect * = VCL_Error {^vmod selector error: s\.element\(select=UNIQUE\): 4 elements were matched$}
+	expect * = VCL_Error {^vmod selector error: s\.element\(select=UNIQUE\): 4 elements were matched$}
+	expect * = End
+
+	expect 0 * Begin req
+	expect * = VCL_Error {^vmod selector error: s\.element\(select=UNIQUE\): 2 elements were matched$}
+	expect * = VCL_Error {^vmod selector error: s\.element\(select=UNIQUE\): 2 elements were matched$}
+	expect * = VCL_Error {^vmod selector error: s\.element\(select=EXACT\): no element matched exactly$}
+	expect * = End
+} -start
+
+client c1 {
+	txreq -hdr "Word: foo"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.Element == "foo"
+	expect resp.http.Element-Unique == "foo"
+	expect resp.http.Element-Exact == "foo"
+	expect resp.http.Element-First == "foo"
+	expect resp.http.Element-Last == "foo"
+	expect resp.http.Element-Shortest == "foo"
+	expect resp.http.Element-Longest == "foo"
+
+	txreq -hdr "Word: foobar"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.Element == ""
+	expect resp.http.Element-Unique == ""
+	expect resp.http.Element-Exact == "foobar"
+	expect resp.http.Element-First == "foobar"
+	expect resp.http.Element-Last == "foo"
+	expect resp.http.Element-Shortest == "foo"
+	expect resp.http.Element-Longest == "foobar"
+
+	txreq -hdr "Word: foobarbaz"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.Element == ""
+	expect resp.http.Element-Unique == ""
+	expect resp.http.Element-Exact == "foobarbaz"
+	expect resp.http.Element-First == "foobarbaz"
+	expect resp.http.Element-Last == "foo"
+	expect resp.http.Element-Shortest == "foo"
+	expect resp.http.Element-Longest == "foobarbaz"
+
+	txreq -hdr "Word: foobarbazquux"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.Element == ""
+	expect resp.http.Element-Unique == ""
+	expect resp.http.Element-Exact == "foobarbazquux"
+	expect resp.http.Element-First == "foobarbazquux"
+	expect resp.http.Element-Last == "foo"
+	expect resp.http.Element-Shortest == "foo"
+	expect resp.http.Element-Longest == "foobarbazquux"
+
+	txreq -hdr "Word: foobarb"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.Element == ""
+	expect resp.http.Element-Unique == ""
+	expect resp.http.Element-Exact == ""
+	expect resp.http.Element-First == "foobar"
+	expect resp.http.Element-Last == "foo"
+	expect resp.http.Element-Shortest == "foo"
+	expect resp.http.Element-Longest == "foobar"
+} -run
+
+logexpect l1 -wait

src/vmod_selector.c

@@ -470,6 +470,42 @@ vmod_set_which(VRT_CTX, struct vmod_selector_set *set, VCL_ENUM selects)
 	return (select(ctx, match, set->vcl_name, selects, "which") + 1);
 }
 
+static unsigned
+get_idx(VRT_CTX, VCL_INT n, const struct vmod_selector_set * const restrict set,
+	const char * const restrict method, VCL_ENUM const restrict selects)
+{
+	struct match_data *match;
+
+	if (n > 0) {
+		if (n > set->nmembers) {
+			VERR(ctx, "%s.%s(%ld): set has %d elements",
+			     set->vcl_name, method, n, set->nmembers);
+			return (UINT_MAX);
+		}
+		return (n - 1);
+	}
+
+	match = get_existing_match_data(ctx, set, method);
+	if (match == NULL || match->n == 0)
+		return (UINT_MAX);
+	return (select(ctx, match, set->vcl_name, selects, method));
+}
+
+VCL_STRING
+vmod_set_element(VRT_CTX, struct vmod_selector_set *set, VCL_INT n,
+		 VCL_ENUM selects)
+{
+	unsigned idx;
+
+	CHECK_OBJ_NOTNULL(ctx, VRT_CTX_MAGIC);
+	CHECK_OBJ_NOTNULL(set, VMOD_SELECTOR_SET_MAGIC);
+
+	idx = get_idx(ctx, n, set, "element", selects);
+	if (idx == UINT_MAX)
+		return (NULL);
+	return (set->members[idx]);
+}
+
 VCL_STRING
 vmod_set_debug(VRT_CTX, struct vmod_selector_set *set)
 {

src/vmod_selector.vcc

@@ -99,6 +99,18 @@ $Method INT .which(ENUM {UNIQUE, EXACT, FIRST, LAST, SHORTEST, LONGEST}
 
 Returns ...
 
+Example::
+
+  if (myset.hasprefix(req.url)) {
+     # ...
+  }
+
+$Method STRING .element(INT n=0,
+			ENUM {UNIQUE, EXACT, FIRST, LAST, SHORTEST, LONGEST}
+			select=UNIQUE)
+
+Returns ...
+
 Example::
 
   if (myset.hasprefix(req.url)) {