Add the quotemeta() function.

README.rst

@@ -72,6 +72,9 @@ SYNOPSIS
   BOOL <obj>.saved([ENUM {REGEX, STR, BE} which] [, INT n]
                    [, ENUM select])
 
+  # utility function
+  STRING re2.quotemeta(STRING)
+
   # VMOD version
   STRING re2.version()
 
@@ -1664,6 +1667,35 @@ Example::
 
 
 
+.. _func_quotemeta:
+
+STRING quotemeta(STRING, STRING fallback)
+-----------------------------------------
+
+::
+
+   STRING quotemeta(
+      STRING,
+      STRING fallback="**QUOTEMETA FUNCTION FAILED**"
+   )
+
+Returns a copy of the argument string with all regex metacharacters
+escaped via backslash. When the returned string is used as a regular
+expression, it will exactly match the original string, regardless of
+any special characters. This function has a purpose similar to a
+``\Q..\E`` sequence within a regex, or the ``literal=true`` setting in
+a regex constructor.
+
+The function fails and returns ``fallback`` if there is insufficient
+workspace for the return string.
+
+Example::
+
+  # The following are always true:
+  re2.quotemeta("1.5-2.0?") == "1\.5\-2\.0\?"
+  re2.match(re2.quotemeta("1.5-2.0?"), "1.5-2.0?"
+
+
 .. _func_version:
 
 STRING version()

src/tests/quotemeta.vtc

+# looks like -*- vcl -*-
+
+varnishtest "quotemeta() function"
+
+varnish v1 -vcl {
+	import ${vmod_re2};
+	backend be { .host = "${bad_ip}"; }
+
+	sub vcl_recv {
+		return(synth(200));
+	}
+
+	sub vcl_synth {
+		# Tests from re2 testing/re2_test.cc
+		set resp.http.q1 =
+		    re2.match(re2.quotemeta("foo"), "foo");
+		set resp.http.q2 =
+		    re2.match(re2.quotemeta("foo.bar"), "foo.bar");
+		set resp.http.q3 =
+		    re2.match(re2.quotemeta("foo\.bar"), "foo\.bar");
+		set resp.http.q4 =
+		    re2.match(re2.quotemeta("[1-9]"), "[1-9]");
+		set resp.http.q5 =
+		    re2.match(re2.quotemeta("1.5-2.0?"), "1.5-2.0?");
+		set resp.http.q6 =
+		    re2.match(re2.quotemeta("\d"), "\d");
+		set resp.http.q7 =
+		    re2.match(re2.quotemeta("Who doesn't like ice cream?"),
+		              "Who doesn't like ice cream?");
+		set resp.http.q8 =
+		    re2.match(re2.quotemeta("((a|b)c?d*e+[f-h]i)"),
+		              "((a|b)c?d*e+[f-h]i)");
+		set resp.http.q9 =
+		    re2.match(re2.quotemeta("((?!)xxx).*yyy"),
+		              "((?!)xxx).*yyy");
+		set resp.http.q10 =
+		    re2.match(re2.quotemeta("(["), "([");
+
+		set resp.http.n1 =
+		    re2.match(re2.quotemeta("..."), "bar");
+		set resp.http.n2 =
+		    re2.match(re2.quotemeta("\."), ".");
+		set resp.http.n3 =
+		    re2.match(re2.quotemeta("\."), "..");
+		set resp.http.n4 =
+		    re2.match(re2.quotemeta("(a)"), "a");
+		set resp.http.n5 =
+		    re2.match(re2.quotemeta("(a|b)"), "a");
+		set resp.http.n6 =
+		    re2.match(re2.quotemeta("(a|b)"), "(a)");
+		set resp.http.n7 =
+		    re2.match(re2.quotemeta("(a|b)"), "a|b");
+		set resp.http.n8 =
+		    re2.match(re2.quotemeta("[0-9]"), "0");
+		set resp.http.n9 =
+		    re2.match(re2.quotemeta("[0-9]"), "0-9");
+		set resp.http.n10 =
+		    re2.match(re2.quotemeta("[0-9]"), "[9]");
+
+		set resp.http.latin1 =
+		    re2.match(re2.quotemeta("3\xb2 = 9"), "3\xb2 = 9");
+
+		set resp.http.utf8-1 =
+		    re2.match(re2.quotemeta("Plácido Domingo"),
+		              "Plácido Domingo", utf8=true);
+		set resp.http.utf8-2 =
+		    re2.match(re2.quotemeta("xyz"), "xyz", utf8=true);
+		set resp.http.utf8-3 =
+		    re2.match(re2.quotemeta("\xc2\xb0"), "\xc2\xb0", utf8=true);
+		set resp.http.utf8-4 =
+		    re2.match(re2.quotemeta("27\xc2\xb0 degrees"),
+		              "27\xc2\xb0 degrees", utf8=true);
+		set resp.http.utf8-5 =
+		    re2.match(re2.quotemeta("\xe2\x80\xb3"),
+		              "\xe2\x80\xb3", utf8=true);
+		set resp.http.utf8-6 =
+		    re2.match(re2.quotemeta("\xf0\x9d\x85\x9f"),
+		              "\xf0\x9d\x85\x9f", utf8=true);
+		set resp.http.utf8-7 =
+		    re2.match(re2.quotemeta("27\xc2\xb0"),
+		              "27\xc2\xb0", utf8=true);
+
+		set resp.http.utf8-n =
+		    re2.match(re2.quotemeta("27\xc2\xb0"),
+		              "27\\xc2\\xb0", utf8=true);
+
+		# Example from re2.h
+		set resp.http.re2-h = re2.quotemeta("1.5-2.0?");
+	}
+} -start
+
+client c1 {
+	txreq
+	rxresp
+	expect resp.http.q1 == "true"
+	expect resp.http.q2 == "true"
+	expect resp.http.q3 == "true"
+	expect resp.http.q4 == "true"
+	expect resp.http.q5 == "true"
+	expect resp.http.q6 == "true"
+	expect resp.http.q7 == "true"
+	expect resp.http.q8 == "true"
+	expect resp.http.q9 == "true"
+	expect resp.http.q10 == "true"
+	expect resp.http.n1 == "false"
+	expect resp.http.n2 == "false"
+	expect resp.http.n3 == "false"
+	expect resp.http.n4 == "false"
+	expect resp.http.n5 == "false"
+	expect resp.http.n6 == "false"
+	expect resp.http.n7 == "false"
+	expect resp.http.n8 == "false"
+	expect resp.http.n9 == "false"
+	expect resp.http.n10 == "false"
+	expect resp.http.latin1 == "true"
+	expect resp.http.utf8-1 == "true"
+	expect resp.http.utf8-2 == "true"
+	expect resp.http.utf8-3 == "true"
+	expect resp.http.utf8-4 == "true"
+	expect resp.http.utf8-5 == "true"
+	expect resp.http.utf8-6 == "true"
+	expect resp.http.utf8-7 == "true"
+	expect resp.http.utf8-n == "false"
+	expect resp.http.re2-h == {1\.5\-2\.0\?}
+} -run

src/vmod_re2.c

@@ -711,6 +711,34 @@ vmod_extract(VRT_CTX, VCL_STRING pattern, VCL_STRING text, VCL_STRING rewrite,
 				one_line);
 }
 
+#define ERR_PREFIX \
+	"re2.quotemeta(\"%.40s\", fallback=\"%.40s\"): "
+
+VCL_STRING
+vmod_quotemeta(VRT_CTX, VCL_STRING unquoted, VCL_STRING fallback)
+{
+	size_t bytes, len;
+	char *ret;
+	const char *err;
+
+	CHECK_OBJ_NOTNULL(ctx, VRT_CTX_MAGIC);
+	ret = WS_Front(ctx->ws);
+	bytes = WS_Reserve(ctx->ws, 0);
+	if (bytes == 0) {
+		VERR(ctx, ERR_PREFIX "workspace overflow", unquoted, fallback);
+		return fallback;
+	}
+	if ((err = vre2_quotemeta(unquoted, ret, bytes, &len)) != NULL) {
+		VERR(ctx, ERR_PREFIX "%s", unquoted, fallback, err);
+		WS_Release(ctx->ws, 0);
+		return fallback;
+	}
+	WS_Release(ctx->ws, len + 1);
+	return ret;
+}
+
+#undef ERR_PREFIX
+
 VCL_STRING
 vmod_version(const struct vrt_ctx *ctx __attribute__((unused)))
 {

src/vmod_re2.vcc

@@ -59,6 +59,9 @@ SYNOPSIS
   BOOL <obj>.saved([ENUM {REGEX, STR, BE} which] [, INT n]
                    [, ENUM select])
 
+  # utility function
+  STRING re2.quotemeta(STRING)
+
   # VMOD version
   STRING re2.version()
 
@@ -1355,6 +1358,25 @@ Example::
      # and which=REGEX by default.
   }
 
+$Function STRING quotemeta(STRING,
+			   STRING fallback="**QUOTEMETA FUNCTION FAILED**")
+
+Returns a copy of the argument string with all regex metacharacters
+escaped via backslash. When the returned string is used as a regular
+expression, it will exactly match the original string, regardless of
+any special characters. This function has a purpose similar to a
+``\Q..\E`` sequence within a regex, or the ``literal=true`` setting in
+a regex constructor.
+
+The function fails and returns ``fallback`` if there is insufficient
+workspace for the return string.
+
+Example::
+
+  # The following are always true:
+  re2.quotemeta("1.5-2.0?") == "1\.5\-2\.0\?"
+  re2.match(re2.quotemeta("1.5-2.0?"), "1.5-2.0?"
+
 $Function STRING version()
 
 Return the version string for this VMOD.

src/vre2/vre2.cpp

@@ -218,6 +218,24 @@ vre2_rewrite(vre2 *vre2, const rewrite_e mode, const char * const text,
 	CATCHALL
 }
 
+const char *
+vre2_quotemeta(const char * const unquoted, char * const dest,
+    const size_t bytes, size_t * const len)
+{
+	try {
+		string result;
+
+		result = RE2::QuoteMeta(unquoted);
+		if (result.size() + 1 > bytes)
+			throw runtime_error("insufficient workspace");
+		*len = result.size();
+		result.copy(dest, *len);
+		dest[*len] = '\0';
+		return NULL;
+	}
+	CATCHALL
+}
+
 const char *
 vre2_fini(vre2 **vre2)
 {

src/vre2/vre2.h

@@ -91,6 +91,9 @@ extern "C" {
 				 const char * const rewrite,
 				 char * const dest, const size_t bytes,
 				 int * const match, size_t * const len);
+	const char *vre2_quotemeta(const char * const unquoted,
+				   char * const dest, const size_t bytes,
+				   size_t * const len);
 
 #ifdef __cplusplus
 }