add the regex.sub() method

README.rst

@@ -34,6 +34,7 @@ CONTENTS
 * STRING regex.backref(INT, STRING)
 * BOOL regex.match(STRING)
 * STRING regex.namedref(STRING, STRING)
+* STRING regex.sub(STRING, STRING, STRING)
 * Object set
 * VOID set.add(STRING)
 * VOID set.compile()
@@ -70,6 +71,14 @@ STRING regex.namedref(STRING, STRING)
 Prototype
 	STRING regex.namedref(STRING name, STRING fallback)
 
+.. _func_regex.sub:
+
+STRING regex.sub(STRING, STRING, STRING)
+----------------------------------------
+
+Prototype
+	STRING regex.sub(STRING text, STRING rewrite, STRING fallback)
+
 .. _obj_set:
 
 Object set

src/tests/sub.vtc

+# looks like -*- vcl -*-
+
+varnishtest "sub() method"
+
+# Tests from re2 testing/re2_test.cc
+
+# regex object
+
+varnish v1 -vcl {
+	import re2 from "${vmod_topbuild}/src/.libs/libvmod_re2.so";
+	backend be { .host = "${bad_ip}"; }
+
+	sub vcl_init {
+	       new piglatin = re2.regex("(qu|[b-df-hj-np-tv-z]*)([a-z]+)");
+	       new word = re2.regex("\w+");
+	       new start = re2.regex("^");
+	       new end = re2.regex("$");
+	       new b = re2.regex("b");
+	       new bplus = re2.regex("b+");
+	       new bstar = re2.regex("b*");
+	}
+
+	sub vcl_recv {
+		return(synth(200));
+	}
+
+	sub vcl_synth {
+		set resp.http.pangram
+		 = piglatin.sub("the quick brown fox jumps over the lazy dogs.",
+		                "\2\1ay");
+		set resp.http.nospam = word.sub("abcd.efghi@google.com",
+				                "\0-NOSPAM");
+		set resp.http.startfoo = start.sub("foo", "(START)");
+		set resp.http.start = start.sub("", "(START)");
+		set resp.http.end = end.sub("", "(END)");
+		set resp.http.ab = b.sub("ababababab", "bb");
+		set resp.http.bb = b.sub("bbbbbb", "bb");
+		set resp.http.bplus = bplus.sub("bbbbbb", "bb");
+		set resp.http.bstar1 = bstar.sub("bbbbbb", "bb");
+		set resp.http.bstar2 = bstar.sub("aaaaa", "bb");
+	}
+
+} -start
+
+client c1 {
+	txreq
+	rxresp
+	expect resp.http.pangram == "ethay quick brown fox jumps over the lazy dogs."
+	expect resp.http.nospam == "abcd-NOSPAM.efghi@google.com"
+	expect resp.http.startfoo == "(START)foo"
+	expect resp.http.start == "(START)"
+	expect resp.http.end == "(END)"
+	expect resp.http.ab == "abbabababab"
+	expect resp.http.bb == "bbbbbbb"
+	expect resp.http.bplus == "bb"
+	expect resp.http.bstar1 == "bb"
+	expect resp.http.bstar2 == "bbaaaaa"
+} -run

src/vmod_re2.c

@@ -381,6 +381,45 @@ vmod_regex_namedref(VRT_CTX, struct vmod_re2_regex *re, VCL_STRING name,
 
 #undef ERR_PREFIX
 
+#define ERR_PREFIX "%s.sub(text=\"%s\", rewrite=\"%s\", fallback=\"%s\"): "
+
+VCL_STRING
+vmod_regex_sub(VRT_CTX, struct vmod_re2_regex *re, VCL_STRING text,
+	       VCL_STRING rewrite, VCL_STRING fallback)
+{
+	int match = 0;
+	size_t bytes, len;
+	char *ret;
+	const char *err;
+
+	CHECK_OBJ_NOTNULL(ctx, VRT_CTX_MAGIC);
+	CHECK_OBJ_NOTNULL(re, VMOD_RE2_REGEX_MAGIC);
+	if (text == NULL)
+		text = "";
+	if (rewrite == NULL)
+		rewrite = "";
+	if (fallback == NULL)
+		fallback = "";
+
+	ret = WS_Snapshot(ctx->ws);
+	bytes = WS_Reserve(ctx->ws, 0);
+	if ((err = vre2_replace(re->vre2, text, rewrite, ret, bytes, &match,
+				&len)) != NULL) {
+		VERR(ctx, ERR_PREFIX "%s", re->vcl_name, text, rewrite,
+		     fallback, err);
+		WS_Release(ctx->ws, 0);
+		return fallback;
+	}
+	if (!match) {
+		WS_Release(ctx->ws, 0);
+		return fallback;
+	}
+	WS_Release(ctx->ws, len);
+	return ret;
+}
+
+#undef ERR_PREFIX
+
 /* Object set */
 
 VCL_VOID

src/vmod_re2.vcc

@@ -24,6 +24,9 @@ $Method STRING .backref(INT ref, STRING fallback = "**BACKREF METHOD FAILED**")
 $Method STRING .namedref(STRING name,
                          STRING fallback = "**NAMEDREF METHOD FAILED**")
 
+$Method STRING .sub(STRING text, STRING rewrite,
+                    STRING fallback = "**SUB METHOD FAILED**")
+
 $Object set(ENUM { none, start, both } anchor="none", BOOL utf8=0,
             BOOL posix_syntax=0, BOOL longest_match=0, INT max_mem=8388608,
 	    BOOL literal=0, BOOL never_nl=0, BOOL dot_nl=0,

src/vre2/vre2.cpp

@@ -81,6 +81,12 @@ vre2::get_group(const char * const name) const
 	}
 }
 
+inline bool
+vre2::replace(string *text, const char * const rewrite) const
+{
+	return RE2::Replace(text, *re_, rewrite);
+}
+
 const char *
 vre2_init(vre2 **vre2p, const char *pattern, unsigned utf8,
     unsigned posix_syntax, unsigned longest_match, long max_mem,
@@ -164,6 +170,26 @@ vre2_get_group(vre2 *vre2, const char * const name, int * const refnum)
 	CATCHALL
 }
 
+const char *
+vre2_replace(vre2 *vre2, const char * const text, const char * const rewrite,
+    char * const dest, const size_t bytes, int * const match,
+    size_t * const len)
+{
+	try {
+		string t(text);
+		*match = vre2->replace(&t, rewrite);
+		if (!*match)
+			return NULL;
+		if (t.size() > bytes + 1)
+			throw runtime_error("insufficient workspace");
+		*len = t.size() + 1;
+		t.copy(dest, *len);
+		dest[*len] = '\0';
+		return NULL;
+	}
+	CATCHALL
+}
+
 const char *
 vre2_fini(vre2 **vre2)
 {

src/vre2/vre2.h

@@ -48,6 +48,7 @@ public:
 		   StringPiece* groups) const;
 	const int ngroups() const;
 	int get_group(const char * const name) const;
+	bool replace(string *text, const char * const rewrite) const;
 };
 #else
 typedef struct vre2 vre2;
@@ -74,6 +75,10 @@ extern "C" {
 				 const char ** const capture, int * const len);
 	const char *vre2_get_group(vre2 *vre2, const char * const name,
 				   int * const refnum);
+	const char *vre2_replace(vre2 *vre2, const char * const text,
+				 const char * const rewrite,
+				 char * const dest, const size_t bytes,
+				 int * const match, size_t * const len);
 
 #ifdef __cplusplus
 }