Reopening leases file on every reading

CMakeLists.txt

@@ -1,7 +1,7 @@
 cmake_minimum_required(VERSION 3.27)
 project(aliencat_exporter)
 
-set(CMAKE_CXX_STANDARD 20)
+set(CMAKE_CXX_STANDARD 23)
 
 find_package(prometheus-cpp CONFIG REQUIRED)
 

DataSources/DnsmasqSource.cpp

@@ -3,35 +3,24 @@
 //
 
 #include "DnsmasqSource.h"
-#include <exception>
 #include <sstream>
-#include <iostream>
+#include <ranges>
 
 DnsmasqSource::DnsmasqSource() {
-    _leases.open("/var/lib/misc/dnsmasq.leases");
-    if(_leases.fail()) {
-        throw std::runtime_error("failed to open leases file");
-    }
 }
 
 std::vector<prometheus::Labels> DnsmasqSource::readLeases() {
-    _leases.clear();
-    _leases.seekg(0);
-
-    std::string line, time, mac, ip, host, id;
-    std::stringstream ss;
+    std::ifstream leases("/var/lib/misc/dnsmasq.leases");
+    std::string line;
     std::vector<prometheus::Labels> result;
+    auto labels = std::array{ "time", "mac", "ip", "host", "id" };
 
-    while(std::getline(_leases, line)) {
-        ss << line;
-        ss >> time >> mac >> ip >> host >> id;
-        result.push_back({
-            {"time", time},
-            {"mac", mac},
-            {"ip", ip},
-            {"host", host},
-            {"id", id}
-        });
+    while(std::getline(leases, line)) {
+        prometheus::Labels lineMap;
+        for(const auto [index, item]: std::views::split(line, ' ') | std::views::enumerate) {
+            lineMap[labels[index]] = std::string_view(item);
+        }
+        result.push_back(lineMap);
     }
 
     return result;

DataSources/DnsmasqSource.h

@@ -10,9 +10,6 @@
 #include <vector>
 
 class DnsmasqSource {
-private:
-    std::ifstream _leases;
-
 public:
     DnsmasqSource();
     std::vector<prometheus::Labels> readLeases();