From f8182333b4126641f6f8a33ecb0ffa1719a06097 Mon Sep 17 00:00:00 2001
From: Tatsuhiro Tsujikawa <tatsuhiro.t@gmail.com>
Date: Sat, 7 Mar 2015 00:20:53 +0900
Subject: [PATCH] asio: Improve date header field precision

---
 src/asio_server.cc               | 20 +-------------------
 src/asio_server.h                |  4 ----
 src/asio_server_http2_handler.cc | 19 ++++++++++++++-----
 src/asio_server_http2_handler.h  |  4 ++++
 4 files changed, 19 insertions(+), 28 deletions(-)

diff --git a/src/asio_server.cc b/src/asio_server.cc
index 2d468e6c..323a8991 100644
--- a/src/asio_server.cc
+++ b/src/asio_server.cc
@@ -36,8 +36,6 @@
 
 #include "asio_server.h"
 
-#include <boost/date_time/posix_time/posix_time.hpp>
-
 #include "asio_server_connection.h"
 #include "util.h"
 
@@ -46,9 +44,7 @@ namespace asio_http2 {
 namespace server {
 
 server::server(std::size_t io_service_pool_size)
-    : io_service_pool_(io_service_pool_size),
-      tick_timer_(io_service_pool_.get_io_service(),
-                  boost::posix_time::seconds(1)) {}
+    : io_service_pool_(io_service_pool_size) {}
 
 boost::system::error_code
 server::listen_and_serve(boost::system::error_code &ec,
@@ -69,8 +65,6 @@ server::listen_and_serve(boost::system::error_code &ec,
     }
   }
 
-  start_timer();
-
   io_service_pool_.run();
 
   return ec;
@@ -123,18 +117,6 @@ boost::system::error_code server::bind_and_listen(boost::system::error_code &ec,
   return ec;
 }
 
-std::shared_ptr<std::string> cached_date;
-
-void server::start_timer() {
-  cached_date = std::make_shared<std::string>(util::http_date(time(nullptr)));
-
-  tick_timer_.async_wait([this](const boost::system::error_code &e) {
-    tick_timer_.expires_at(tick_timer_.expires_at() +
-                           boost::posix_time::seconds(1));
-    start_timer();
-  });
-}
-
 void server::start_accept(boost::asio::ssl::context &tls_context,
                           tcp::acceptor &acceptor, serve_mux &mux) {
   auto new_connection = std::make_shared<connection<ssl_socket>>(
diff --git a/src/asio_server.h b/src/asio_server.h
index 9f120a80..bb4159e9 100644
--- a/src/asio_server.h
+++ b/src/asio_server.h
@@ -84,14 +84,10 @@ private:
                                             const std::string &port,
                                             int backlog);
 
-  void start_timer();
-
   /// The pool of io_service objects used to perform asynchronous
   /// operations.
   io_service_pool io_service_pool_;
 
-  boost::asio::deadline_timer tick_timer_;
-
   /// Acceptor used to listen for incoming connections.
   std::vector<tcp::acceptor> acceptors_;
 
diff --git a/src/asio_server_http2_handler.cc b/src/asio_server_http2_handler.cc
index af7bdce7..76436aec 100644
--- a/src/asio_server_http2_handler.cc
+++ b/src/asio_server_http2_handler.cc
@@ -41,8 +41,6 @@ namespace asio_http2 {
 
 namespace server {
 
-extern std::shared_ptr<std::string> cached_date;
-
 namespace {
 int stream_error(nghttp2_session *session, int32_t stream_id,
                  uint32_t error_code) {
@@ -229,10 +227,21 @@ int on_frame_not_send_callback(nghttp2_session *session,
 http2_handler::http2_handler(boost::asio::io_service &io_service,
                              connection_write writefun, serve_mux &mux)
     : writefun_(writefun), mux_(mux), io_service_(io_service),
-      session_(nullptr), buf_(nullptr), buflen_(0), inside_callback_(false) {}
+      session_(nullptr), buf_(nullptr), buflen_(0), inside_callback_(false),
+      tstamp_cached_(time(nullptr)),
+      formatted_date_(util::http_date(tstamp_cached_)) {}
 
 http2_handler::~http2_handler() { nghttp2_session_del(session_); }
 
+const std::string &http2_handler::http_date() {
+  auto t = time(nullptr);
+  if (t != tstamp_cached_) {
+    tstamp_cached_ = t;
+    formatted_date_ = util::http_date(t);
+  }
+  return formatted_date_;
+}
+
 int http2_handler::start() {
   int rv;
 
@@ -317,9 +326,9 @@ int http2_handler::start_response(stream &strm) {
   auto nva = std::vector<nghttp2_nv>();
   nva.reserve(2 + header.size());
   auto status = util::utos(res.status_code());
-  auto date = cached_date;
+  auto date = http_date();
   nva.push_back(nghttp2::http2::make_nv_ls(":status", status));
-  nva.push_back(nghttp2::http2::make_nv_ls("date", *date));
+  nva.push_back(nghttp2::http2::make_nv_ls("date", date));
   for (auto &hd : header) {
     nva.push_back(nghttp2::http2::make_nv(hd.first, hd.second.value,
                                           hd.second.sensitive));
diff --git a/src/asio_server_http2_handler.h b/src/asio_server_http2_handler.h
index d08475a2..2f5d69b9 100644
--- a/src/asio_server_http2_handler.h
+++ b/src/asio_server_http2_handler.h
@@ -87,6 +87,8 @@ public:
 
   boost::asio::io_service &io_service();
 
+  const std::string &http_date();
+
   template <size_t N>
   int on_read(const boost::array<uint8_t, N> &buffer, std::size_t len) {
     callback_guard cg(*this);
@@ -152,6 +154,8 @@ private:
   const uint8_t *buf_;
   std::size_t buflen_;
   bool inside_callback_;
+  time_t tstamp_cached_;
+  std::string formatted_date_;
 };
 
 } // namespace server