Add the element parameter to .which().

README.rst

@@ -39,9 +39,9 @@ SYNOPSIS
   # Match properties
   INT <obj>.nmatches()
   BOOL <obj>.matched([INT n] [, STRING element] [, ENUM select])
-  INT <obj>.which([ENUM select])
+  INT <obj>.which([ENUM select] [, STRING element])
 
-  # Retrieving objects after match
+  # Retrieving objects by index, by string, or after match
   STRING  <obj>.element([INT n] [, ENUM select])
   STRING  <obj>.string([INT n]  [, STRING element] [, ENUM select])
   INT     <obj>.integer([INT n] [, STRING element] [, ENUM select])
@@ -714,32 +714,37 @@ Example::
 
 .. _xset.which():
 
-INT xset.which(ENUM select)
----------------------------
+INT xset.which(ENUM select, STRING element)
+-------------------------------------------
 
 ::
 
       INT xset.which(
-            ENUM {UNIQUE, EXACT, FIRST, LAST, SHORTEST, LONGEST} select=UNIQUE
+            ENUM {UNIQUE, EXACT, FIRST, LAST, SHORTEST, LONGEST} select=UNIQUE,
+            STRING element=0
       )
 
-After a successful ``.match()`` or ``.hasprefix()`` call for the same
-set object in the same task scope, return the index of the matching
-element indicated by ``select``. The numbering corresponds to the
-order of ``.add()`` calls in ``vcl_init``.
+Return the index of the element indicated by ``element`` or
+``select``. The numbering corresponds to the order of ``.add()`` calls
+in ``vcl_init``, starting from 1.
 
-Return 0 if the most recent ``.match()`` or ``.hasprefix()`` call
-returned ``false``.
+If the ``element`` parameter is set, then return the numeric index for
+that string in the set.
 
-If more than one element matched after calling ``.hasprefix()``, the
-index is chosen with the ``select`` parameter, according to the rules
-given above. By default, ``select`` is ``UNIQUE``.
+If ``element`` is unset, then the index is chosen with the ``select``
+parameter, and refers to the previous ``.match()`` or ``.hasprefix()``
+call for the same set object in the same task scope, according to the
+rules given above. By default, ``select`` is ``UNIQUE``.
+
+If ``element`` is unset, and the most recent ``.match()`` or
+``.hasprefix()`` call returned ``false``, return 0.
 
 ``.which()`` invokes VCL failure if:
 
-* The choice of ``select`` indicates failure, as documented above; that
-  is, if ``select`` is ``UNIQUE`` or ``EXACT``, but there was no unique
-  or exact match, respectively.
+* The choice of ``element`` or ``select`` indicates failure, as
+  documented above; that is, if ``element`` is a string that is not in
+  the set, or ``select`` is ``UNIQUE`` or ``EXACT``, but there was no
+  unique or exact match, respectively.
 
 * There was no prior invocation of ``.match()`` or ``.hasprefix()`` in
   the same task scope.
@@ -752,6 +757,10 @@ Example::
      }
   }
 
+  if (myset.which(element=bereq.url) == 1) {
+         call do_if_the_url_was_the_first_element;
+  }
+
 .. _xset.element():
 
 STRING xset.element(INT n, ENUM select)

src/tests/match.vtc

@@ -31,6 +31,11 @@ varnish v1 -vcl {
 		set resp.http.Match-Zab = t.match("zab");
 		set resp.http.Match-Xuuq = t.match("xuuq");
 		set resp.http.Match-Raboof = t.match("raboof");
+		set resp.http.Which-Foo = t.which(element="foo");
+		set resp.http.Which-Bar = t.which(element="bar");
+		set resp.http.Which-Baz = t.which(element="baz");
+		set resp.http.Which-Quux = t.which(element="quux");
+		set resp.http.Which-Foobar = t.which(element="foobar");
 		return (deliver);
 	}
 } -start
@@ -48,6 +53,11 @@ client c1 {
 	expect resp.http.Match-Zab == "false"
 	expect resp.http.Match-Xuuq == "false"
 	expect resp.http.Match-Raboof == "false"
+	expect resp.http.Which-Foo == 1
+	expect resp.http.Which-Bar == 2
+	expect resp.http.Which-Baz == 3
+	expect resp.http.Which-Quux == 4
+	expect resp.http.Which-Foobar == 5
 } -run
 
 varnish v1 -vcl {
@@ -877,9 +887,36 @@ client c1 {
 	expect resp.reason == "VCL failed"
 } -run
 
+varnish v1 -vcl {
+	import ${vmod_selector};
+	backend b None;
+
+	sub vcl_init {
+		new s = selector.set();
+		s.add("foo");
+		s.compile();
+	}
+
+	sub vcl_recv {
+		set req.http.Which = s.which(element="bar");
+	}
+}
+
+client c1 {
+	txreq
+	rxresp
+	expect resp.status == 503
+	expect resp.reason == "VCL failed"
+} -run
+
 logexpect l1 -v v1 -d 1 -g vxid -q "VCL_Error" {
 	expect 0 * Begin req
-	    expect * = VCL_Error {^vmod selector failure: s\.matched\(2\) out of range \(1 members\)$}
+	expect * = VCL_Error {^vmod selector failure: s\.matched\(2\) out of range \(1 members\)$}
+	expect * = VCL_return fail
+	expect * = End
+
+	expect 0 * Begin req
+	expect * = VCL_Error {^vmod selector failure: s\.which\(element="bar"\): no such element$}
 	expect * = VCL_return fail
 	expect * = End
 } -run

src/vmod_selector.c

@@ -689,14 +689,27 @@ select(VRT_CTX, const struct match_data * const restrict match,
 }
 
 VCL_INT
-vmod_set_which(VRT_CTX, struct vmod_selector_set *set, VCL_ENUM selects)
+vmod_set_which(VRT_CTX, struct vmod_selector_set *set, VCL_ENUM selects,
+	       VCL_STRING element)
 {
 	struct match_data *match;
 
 	CHECK_OBJ_NOTNULL(ctx, VRT_CTX_MAGIC);
 	CHECK_OBJ_NOTNULL(set, VMOD_SELECTOR_SET_MAGIC);
 
+	if (element != NULL)
+		if (!vmod_set_match(ctx, TRUST_ME(set), element)) {
+			VFAIL(ctx, "%s.which(element=\"%s\"): no such element",
+			      set->vcl_name, element);
+			return (UINT_MAX);
+		}
+
 	match = get_existing_match_data(ctx, set, "which");
+	if (element != NULL) {
+		CHECK_OBJ_NOTNULL(match, MATCH_DATA_MAGIC);
+		assert(match->n == 1);
+		return (match->indices[0] + 1);
+	}
 	if (match == NULL || match->n == 0)
 		return (0);
 	return (select(ctx, match, set->vcl_name, selects, "which") + 1);

src/vmod_selector.vcc

@@ -35,9 +35,9 @@ SYNOPSIS
   # Match properties
   INT <obj>.nmatches()
   BOOL <obj>.matched([INT n] [, STRING element] [, ENUM select])
-  INT <obj>.which([ENUM select])
+  INT <obj>.which([ENUM select] [, STRING element])
 
-  # Retrieving objects after match
+  # Retrieving objects by index, by string, or after match
   STRING  <obj>.element([INT n] [, ENUM select])
   STRING  <obj>.string([INT n]  [, STRING element] [, ENUM select])
   INT     <obj>.integer([INT n] [, STRING element] [, ENUM select])
@@ -663,25 +663,29 @@ Example::
   }
 
 $Method INT .which(ENUM {UNIQUE, EXACT, FIRST, LAST, SHORTEST, LONGEST}
-		   select=UNIQUE)
+		   select=UNIQUE, STRING element=0)
 
-After a successful ``.match()`` or ``.hasprefix()`` call for the same
-set object in the same task scope, return the index of the matching
-element indicated by ``select``. The numbering corresponds to the
-order of ``.add()`` calls in ``vcl_init``.
+Return the index of the element indicated by ``element`` or
+``select``. The numbering corresponds to the order of ``.add()`` calls
+in ``vcl_init``, starting from 1.
+
+If the ``element`` parameter is set, then return the numeric index for
+that string in the set.
 
-Return 0 if the most recent ``.match()`` or ``.hasprefix()`` call
-returned ``false``.
+If ``element`` is unset, then the index is chosen with the ``select``
+parameter, and refers to the previous ``.match()`` or ``.hasprefix()``
+call for the same set object in the same task scope, according to the
+rules given above. By default, ``select`` is ``UNIQUE``.
 
-If more than one element matched after calling ``.hasprefix()``, the
-index is chosen with the ``select`` parameter, according to the rules
-given above. By default, ``select`` is ``UNIQUE``.
+If ``element`` is unset, and the most recent ``.match()`` or
+``.hasprefix()`` call returned ``false``, return 0.
 
 ``.which()`` invokes VCL failure if:
 
-* The choice of ``select`` indicates failure, as documented above; that
-  is, if ``select`` is ``UNIQUE`` or ``EXACT``, but there was no unique
-  or exact match, respectively.
+* The choice of ``element`` or ``select`` indicates failure, as
+  documented above; that is, if ``element`` is a string that is not in
+  the set, or ``select`` is ``UNIQUE`` or ``EXACT``, but there was no
+  unique or exact match, respectively.
 
 * There was no prior invocation of ``.match()`` or ``.hasprefix()`` in
   the same task scope.
@@ -694,6 +698,10 @@ Example::
      }
   }
 
+  if (myset.which(element=bereq.url) == 1) {
+         call do_if_the_url_was_the_first_element;
+  }
+
 $Method STRING .element(INT n=0,
 			ENUM {UNIQUE, EXACT, FIRST, LAST, SHORTEST, LONGEST}
 			select=UNIQUE)