src: Rewrite http:create_via_header_value

src/shrpx-unittest.cc

@@ -123,6 +123,8 @@ int main(int argc, char *argv[]) {
                    shrpx::test_shrpx_worker_match_downstream_addr_group) ||
       !CU_add_test(pSuite, "http_create_forwarded",
                    shrpx::test_shrpx_http_create_forwarded) ||
+      !CU_add_test(pSuite, "http_create_via_header_value",
+                   shrpx::test_shrpx_http_create_via_header_value) ||
       !CU_add_test(pSuite, "util_streq", shrpx::test_util_streq) ||
       !CU_add_test(pSuite, "util_strieq", shrpx::test_util_strieq) ||
       !CU_add_test(pSuite, "util_inp_strlower",

src/shrpx_http.cc

@@ -50,17 +50,6 @@ std::string create_error_html(unsigned int status_code) {
   return res;
 }
 
-std::string create_via_header_value(int major, int minor) {
-  std::string hdrs;
-  hdrs += static_cast<char>(major + '0');
-  if (major < 2) {
-    hdrs += '.';
-    hdrs += static_cast<char>(minor + '0');
-  }
-  hdrs += " nghttpx";
-  return hdrs;
-}
-
 std::string create_forwarded(int params, const StringRef &node_by,
                              const StringRef &node_for, const StringRef &host,
                              const StringRef &proto) {

src/shrpx_http.h

@@ -31,13 +31,23 @@
 
 #include <nghttp2/nghttp2.h>
 
+#include "util.h"
+
 namespace shrpx {
 
 namespace http {
 
 std::string create_error_html(unsigned int status_code);
 
-std::string create_via_header_value(int major, int minor);
+template <typename OutputIt>
+OutputIt create_via_header_value(OutputIt dst, int major, int minor) {
+  *dst++ = static_cast<char>(major + '0');
+  if (major < 2) {
+    *dst++ = '.';
+    *dst++ = static_cast<char>(minor + '0');
+  }
+  return util::copy_lit(dst, " nghttpx");
+}
 
 // Returns generated RFC 7239 Forwarded header field value.  The
 // |params| is bitwise-OR of zero or more of shrpx_forwarded_param

src/shrpx_http2_downstream_connection.cc

@@ -266,6 +266,8 @@ int Http2DownstreamConnection::push_request_headers() {
 
   const auto &req = downstream_->request();
 
+  auto &balloc = downstream_->get_block_allocator();
+
   auto &httpconf = get_config()->http;
   auto &http2conf = get_config()->http2;
 
@@ -403,19 +405,28 @@ int Http2DownstreamConnection::push_request_headers() {
     nva.push_back(http2::make_nv_ls_nocopy("x-forwarded-proto", req.scheme));
   }
 
-  std::string via_value;
   auto via = req.fs.header(http2::HD_VIA);
   if (httpconf.no_via) {
     if (via) {
       nva.push_back(http2::make_nv_ls_nocopy("via", (*via).value));
     }
   } else {
+    size_t vialen = 16;
     if (via) {
-      via_value = (*via).value.str();
-      via_value += ", ";
+      vialen += via->value.size() + 2;
     }
-    via_value += http::create_via_header_value(req.http_major, req.http_minor);
-    nva.push_back(http2::make_nv_ls("via", via_value));
+
+    auto iov = make_byte_ref(balloc, vialen + 1);
+    auto p = iov.base;
+
+    if (via) {
+      p = std::copy(std::begin(via->value), std::end(via->value), p);
+      p = util::copy_lit(p, ", ");
+    }
+    p = http::create_via_header_value(p, req.http_major, req.http_minor);
+    *p = '\0';
+
+    nva.push_back(http2::make_nv_ls_nocopy("via", StringRef{iov.base, p}));
   }
 
   auto te = req.fs.header(http2::HD_TE);

src/shrpx_http2_upstream.cc

@@ -1399,7 +1399,6 @@ int Http2Upstream::on_downstream_header_complete(Downstream *downstream) {
   // field.
   nva.reserve(resp.fs.headers().size() + 4 +
               httpconf.add_response_headers.size());
-  std::string via_value;
 
   auto response_status = http2::stringify_status(resp.http_status);
   if (response_status.empty()) {
@@ -1453,13 +1452,23 @@ int Http2Upstream::on_downstream_header_complete(Downstream *downstream) {
       nva.push_back(http2::make_nv_ls_nocopy("via", (*via).value));
     }
   } else {
+    // we don't create more than 16 bytes in
+    // http::create_via_header_value.
+    size_t len = 16;
     if (via) {
-      via_value = (*via).value.str();
-      via_value += ", ";
+      len += via->value.size() + 2;
     }
-    via_value +=
-        http::create_via_header_value(resp.http_major, resp.http_minor);
-    nva.push_back(http2::make_nv_ls("via", via_value));
+
+    auto iov = make_byte_ref(balloc, len + 1);
+    auto p = iov.base;
+    if (via) {
+      p = std::copy(std::begin(via->value), std::end(via->value), p);
+      p = util::copy_lit(p, ", ");
+    }
+    p = http::create_via_header_value(p, resp.http_major, resp.http_minor);
+    *p = '\0';
+
+    nva.push_back(http2::make_nv_ls_nocopy("via", StringRef{iov.base, p}));
   }
 
   for (auto &p : httpconf.add_response_headers) {

src/shrpx_http_downstream_connection.cc

@@ -424,7 +424,10 @@ int HttpDownstreamConnection::push_request_headers() {
       buf->append((*via).value);
       buf->append(", ");
     }
-    buf->append(http::create_via_header_value(req.http_major, req.http_minor));
+    std::array<char, 16> viabuf;
+    auto end = http::create_via_header_value(viabuf.data(), req.http_major,
+                                             req.http_minor);
+    buf->append(viabuf.data(), end - viabuf.data());
     buf->append("\r\n");
   }
 

src/shrpx_http_test.cc

@@ -72,4 +72,18 @@ void test_shrpx_http_create_forwarded(void) {
                 StringRef::from_lit(""), StringRef::from_lit("")));
 }
 
+void test_shrpx_http_create_via_header_value(void) {
+  std::array<char, 16> buf;
+
+  auto end = http::create_via_header_value(std::begin(buf), 1, 1);
+
+  CU_ASSERT(("1.1 nghttpx" == StringRef{std::begin(buf), end}));
+
+  std::fill(std::begin(buf), std::end(buf), '\0');
+
+  end = http::create_via_header_value(std::begin(buf), 2, 0);
+
+  CU_ASSERT(("2 nghttpx" == StringRef{std::begin(buf), end}));
+}
+
 } // namespace shrpx

src/shrpx_http_test.h

@@ -32,6 +32,7 @@
 namespace shrpx {
 
 void test_shrpx_http_create_forwarded(void);
+void test_shrpx_http_create_via_header_value(void);
 
 } // namespace shrpx
 

src/shrpx_https_upstream.cc

@@ -1074,8 +1074,10 @@ int HttpsUpstream::on_downstream_header_complete(Downstream *downstream) {
       buf->append((*via).value);
       buf->append(", ");
     }
-    buf->append(
-        http::create_via_header_value(resp.http_major, resp.http_minor));
+    std::array<char, 16> viabuf;
+    auto end = http::create_via_header_value(viabuf.data(), resp.http_major,
+                                             resp.http_minor);
+    buf->append(viabuf.data(), end - std::begin(viabuf));
     buf->append("\r\n");
   }
 

src/shrpx_spdy_upstream.cc

@@ -1075,8 +1075,10 @@ int SpdyUpstream::on_downstream_header_complete(Downstream *downstream) {
       via_value = via->value.str();
       via_value += ", ";
     }
-    via_value +=
-        http::create_via_header_value(resp.http_major, resp.http_minor);
+    std::array<char, 16> viabuf;
+    auto end = http::create_via_header_value(std::begin(viabuf),
+                                             resp.http_major, resp.http_minor);
+    via_value.append(std::begin(viabuf), end);
     nv[hdidx++] = "via";
     nv[hdidx++] = via_value.c_str();
   }