From 9fc1f85102cb57f5346c13108e577d2cb4e081cb Mon Sep 17 00:00:00 2001
From: Tatsuhiro Tsujikawa <tatsuhiro.t@gmail.com>
Date: Thu, 8 Jun 2023 19:33:23 +0900
Subject: [PATCH] Fix build error without libev

Check libev availability, and guard the usage of libev in util.h.
---
 cmakeconfig.h.in | 3 +++
 configure.ac     | 4 ++++
 src/util.h       | 6 +++++-
 3 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/cmakeconfig.h.in b/cmakeconfig.h.in
index 2e357d53..f4e2bb60 100644
--- a/cmakeconfig.h.in
+++ b/cmakeconfig.h.in
@@ -90,3 +90,6 @@
 
 /* Define to 1 if you have `libngtcp2_crypto_openssl` library. */
 #cmakedefine HAVE_LIBNGTCP2_CRYPTO_OPENSSL
+
+/* Define to 1 if you have `libev` library. */
+#cmakedefine HAVE_LIBEV 1
diff --git a/configure.ac b/configure.ac
index 6e18aa71..218a767b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -433,6 +433,10 @@ if test "x${request_libev}" != "xno"; then
   else
     have_libev=yes
   fi
+
+  if test "x${have_libev}" = "xyes"; then
+    AC_DEFINE([HAVE_LIBEV], [1], [Define to 1 if you have `libev` library.])
+  fi
 fi
 
 if test "x${request_libev}" = "xyes" &&
diff --git a/src/util.h b/src/util.h
index 6b45922d..074a607b 100644
--- a/src/util.h
+++ b/src/util.h
@@ -47,7 +47,9 @@
 #include <map>
 #include <random>
 
-#include <ev.h>
+#ifdef HAVE_LIBEV
+#  include <ev.h>
+#endif // HAVE_LIBEV
 
 #include "url-parser/url_parser.h"
 
@@ -697,6 +699,7 @@ template <typename Clock, typename Rep> Rep clock_precision() {
   return duration.count();
 }
 
+#ifdef HAVE_LIBEV
 template <typename Duration = std::chrono::steady_clock::duration>
 Duration duration_from(ev_tstamp d) {
   return std::chrono::duration_cast<Duration>(std::chrono::duration<double>(d));
@@ -705,6 +708,7 @@ Duration duration_from(ev_tstamp d) {
 template <typename Duration> ev_tstamp ev_tstamp_from(const Duration &d) {
   return std::chrono::duration<double>(d).count();
 }
+#endif // HAVE_LIBEV
 
 int make_socket_closeonexec(int fd);
 int make_socket_nonblocking(int fd);