core: move to inotify for monitoring the config files

instead of manually polling every second which is not efficient, use inotify.

an added bonus is that inotify is much much faster

src/config/ConfigManager.cpp

@@ -1,6 +1,7 @@
 #include <re2/re2.h>
 
 #include "ConfigManager.hpp"
+#include "ConfigWatcher.hpp"
 #include "../managers/KeybindManager.hpp"
 #include "../Compositor.hpp"
 
@@ -372,8 +373,8 @@ static Hyprlang::CParseResult handlePlugin(const char* c, const char* v) {
 CConfigManager::CConfigManager() {
     const auto ERR = verifyConfigExists();
 
-    configPaths.emplace_back(getMainConfigPath());
-    m_pConfig = std::make_unique<Hyprlang::CConfig>(configPaths.begin()->c_str(), Hyprlang::SConfigOptions{.throwAllErrors = true, .allowMissingConfig = true});
+    m_configPaths.emplace_back(getMainConfigPath());
+    m_pConfig = std::make_unique<Hyprlang::CConfig>(m_configPaths.begin()->c_str(), Hyprlang::SConfigOptions{.throwAllErrors = true, .allowMissingConfig = true});
 
     m_pConfig->addConfigValue("general:border_size", Hyprlang::INT{1});
     m_pConfig->addConfigValue("general:no_border_on_floating", Hyprlang::INT{0});
@@ -795,7 +796,7 @@ std::string CConfigManager::getConfigString() {
     std::string configString;
     std::string currFileContent;
 
-    for (const auto& path : configPaths) {
+    for (const auto& path : m_configPaths) {
         std::ifstream configFile(path);
         configString += ("\n\nConfig File: " + path + ": ");
         if (!configFile.is_open()) {
@@ -883,10 +884,10 @@ std::optional<std::string> CConfigManager::resetHLConfig() {
     finalExecRequests.clear();
 
     // paths
-    configPaths.clear();
+    m_configPaths.clear();
     std::string mainConfigPath = getMainConfigPath();
     Debug::log(LOG, "Using config: {}", mainConfigPath);
-    configPaths.push_back(mainConfigPath);
+    m_configPaths.emplace_back(mainConfigPath);
 
     const auto RET = verifyConfigExists();
 
@@ -897,6 +898,8 @@ void CConfigManager::postConfigReload(const Hyprlang::CParseResult& result) {
     static const auto PENABLEEXPLICIT     = CConfigValue<Hyprlang::INT>("render:explicit_sync");
     static int        prevEnabledExplicit = *PENABLEEXPLICIT;
 
+    g_pConfigWatcher->setWatchList(m_configPaths);
+
     for (auto const& w : g_pCompositor->m_vWindows) {
         w->uncacheWindowDecos();
     }
@@ -1029,17 +1032,14 @@ void CConfigManager::postConfigReload(const Hyprlang::CParseResult& result) {
 
 void CConfigManager::init() {
 
+    g_pConfigWatcher->setOnChange([this](const CConfigWatcher::SConfigWatchEvent& e) {
+        Debug::log(LOG, "CConfigManager: file {} modified, reloading", e.file);
+        reload();
+    });
+
     const std::string CONFIGPATH = getMainConfigPath();
     reload();
 
-    struct stat fileStat;
-    int         err = stat(CONFIGPATH.c_str(), &fileStat);
-    if (err != 0) {
-        Debug::log(WARN, "Error at statting config, error {}", errno);
-    }
-
-    configModifyTimes[CONFIGPATH] = fileStat.st_mtime;
-
     isFirstLaunch = false;
 }
 
@@ -1080,37 +1080,6 @@ std::string CConfigManager::parseKeyword(const std::string& COMMAND, const std::
     return RET.error ? RET.getError() : "";
 }
 
-void CConfigManager::tick() {
-    std::string CONFIGPATH = getMainConfigPath();
-    if (!std::filesystem::exists(CONFIGPATH)) {
-        Debug::log(ERR, "Config doesn't exist??");
-        return;
-    }
-
-    bool parse = false;
-
-    for (auto const& cf : configPaths) {
-        struct stat fileStat;
-        int         err = stat(cf.c_str(), &fileStat);
-        if (err != 0) {
-            Debug::log(WARN, "Error at ticking config at {}, error {}: {}", cf, err, strerror(err));
-            continue;
-        }
-
-        // check if we need to reload cfg
-        if (fileStat.st_mtime != configModifyTimes[cf] || m_bForceReload) {
-            parse                 = true;
-            configModifyTimes[cf] = fileStat.st_mtime;
-        }
-    }
-
-    if (parse) {
-        m_bForceReload = false;
-
-        reload();
-    }
-}
-
 Hyprlang::CConfigValue* CConfigManager::getConfigValueSafeDevice(const std::string& dev, const std::string& val, const std::string& fallback) {
 
     const auto VAL = m_pConfig->getSpecialConfigValuePtr("device", val.c_str(), dev.c_str());
@@ -1719,8 +1688,7 @@ void CConfigManager::handlePluginLoads() {
 
     if (pluginsChanged) {
         g_pHyprError->destroy();
-        m_bForceReload = true;
-        tick();
+        reload();
     }
 }
 
@@ -2732,16 +2700,8 @@ std::optional<std::string> CConfigManager::handleSource(const std::string& comma
             Debug::log(ERR, "source= file doesn't exist: {}", value);
             return "source= file " + value + " doesn't exist!";
         }
-        configPaths.push_back(value);
+        m_configPaths.emplace_back(value);
 
-        struct stat fileStat;
-        int         err = stat(value.c_str(), &fileStat);
-        if (err != 0) {
-            Debug::log(WARN, "Error at ticking config at {}, error {}: {}", value, err, strerror(err));
-            return {};
-        }
-
-        configModifyTimes[value]     = fileStat.st_mtime;
         auto configCurrentPathBackup = configCurrentPath;
         configCurrentPath            = value;