From 8fbada6c7542d233afb4677c19a0395f77d32519 Mon Sep 17 00:00:00 2001
From: Roland Reichwein <mail@reichwein.it>
Date: Fri, 15 May 2020 19:36:52 +0200
Subject: Speed up GetPath() with look up table

---
 config.cpp | 53 +++++++++++++++++++++++++++++++++--------------------
 config.h   |  4 ++++
 2 files changed, 37 insertions(+), 20 deletions(-)

diff --git a/config.cpp b/config.cpp
index ed28ea9..b892317 100644
--- a/config.cpp
+++ b/config.cpp
@@ -160,7 +160,15 @@ void Config::readConfigfile(std::string filename)
   }
  }
 
- // expand socket sites
+ expand_socket_sites();
+
+ validate();
+
+ create_look_up_table();
+}
+
+void Config::expand_socket_sites()
+{
  for (auto& socket: m_sockets) {
   if (socket.serve_sites.empty()) {
    for (const auto& site: m_sites) {
@@ -168,8 +176,6 @@ void Config::readConfigfile(std::string filename)
    }
   }
  }
-
- validate();
 }
 
 // just throws on inconsistency
@@ -183,7 +189,18 @@ void Config::validate()
     throw std::runtime_error("Found serve_site "s + serve_site + " without configured site"s);
   }
  }
- 
+}
+
+void Config::create_look_up_table()
+{
+ for (auto& socket: m_sockets) {
+  for (const auto& site_name: socket.serve_sites) {
+   Site& site {m_sites.at(site_name)}; // omit error check: validation previously made sure this exists
+   for (const auto& host: site.hosts) {
+    socket.host_lut[host] = &site;
+   }
+  }
+ }
 }
 
 Config::Config(const std::string& filename)
@@ -276,22 +293,18 @@ const Path& Config::GetPath(const Socket& socket, const std::string& requested_h
 
  RemovePortFromHostname(host);
 
- for (const auto& site_name: socket.serve_sites) {
-  const Site& site {m_sites.at(site_name)}; // omit error check: validation previously made sure this exists
-
-  if (site.hosts.find(host) != site.hosts.end()) {
-   for (const auto& path: site.paths) {
-    if (boost::starts_with(requested_path, path.requested) &&
-        ("/?"s.find(requested_path[path.requested.size()]) != std::string::npos ||
-         requested_path[path.requested.size()] == 0 ||
-         requested_path[path.requested.size() - 1] == '/'
-        ) &&
-        path.requested.size() > path_len)
-    {
-     path_len = path.requested.size();
-     result = &path;
-    }
-   }
+ const Site& site{*socket.host_lut.at(host)}; // can throw out_of_range
+
+ for (const auto& path: site.paths) {
+  if (boost::starts_with(requested_path, path.requested) &&
+      ("/?"s.find(requested_path[path.requested.size()]) != std::string::npos ||
+       requested_path[path.requested.size()] == 0 ||
+       requested_path[path.requested.size() - 1] == '/'
+      ) &&
+      path.requested.size() > path_len)
+  {
+   path_len = path.requested.size();
+   result = &path;
   }
  }
 
diff --git a/config.h b/config.h
index e60bba5..a021c80 100644
--- a/config.h
+++ b/config.h
@@ -37,6 +37,8 @@ struct Socket
  std::string port;
  SocketProtocol protocol;
  std::unordered_set<std::string> serve_sites; // if empty, automatically expand to all configured sites
+ 
+ std::unordered_map <std::string, Site*> host_lut; // look up table for fast server decision in GetPath()
 };
 
 class Config
@@ -44,7 +46,9 @@ class Config
  const std::string default_filename{"/etc/webserver.conf"};
 
  void readConfigfile(std::string filename);
+ void expand_socket_sites();
  void validate();
+ void create_look_up_table();
 
  std::string m_user;
  std::string m_group;
-- 
cgit v1.2.3