refactor: modernize standard library usage across six Sonar rules (#5930)

src/config.cpp

@@ -742,20 +742,20 @@ namespace config {
     },  // qsv
 
     {
-      (int) amd::usage_h264_e::ultralowlatency,  // usage (h264)
+      std::to_underlying(amd::usage_h264_e::ultralowlatency),  // usage (h264)
-      (int) amd::usage_hevc_e::ultralowlatency,  // usage (hevc)
+      std::to_underlying(amd::usage_hevc_e::ultralowlatency),  // usage (hevc)
-      (int) amd::usage_av1_e::ultralowlatency,  // usage (av1)
+      std::to_underlying(amd::usage_av1_e::ultralowlatency),  // usage (av1)
-      (int) amd::rc_h264_e::vbr_latency,  // rate control (h264)
+      std::to_underlying(amd::rc_h264_e::vbr_latency),  // rate control (h264)
-      (int) amd::rc_hevc_e::vbr_latency,  // rate control (hevc)
+      std::to_underlying(amd::rc_hevc_e::vbr_latency),  // rate control (hevc)
-      (int) amd::rc_av1_e::vbr_latency,  // rate control (av1)
+      std::to_underlying(amd::rc_av1_e::vbr_latency),  // rate control (av1)
       0,  // enforce_hrd
-      (int) amd::quality_h264_e::balanced,  // quality (h264)
+      std::to_underlying(amd::quality_h264_e::balanced),  // quality (h264)
-      (int) amd::quality_hevc_e::balanced,  // quality (hevc)
+      std::to_underlying(amd::quality_hevc_e::balanced),  // quality (hevc)
-      (int) amd::quality_av1_e::balanced,  // quality (av1)
+      std::to_underlying(amd::quality_av1_e::balanced),  // quality (av1)
       0,  // preanalysis
       1,  // vbaq
       {},  // max_au_size (disabled by default)
-      (int) amd::coder_e::_auto,  // coder
+      std::to_underlying(amd::coder_e::_auto),  // coder
     },  // amd
 
     {
@@ -1021,8 +1021,8 @@ namespace config {
   /**
    * @brief Parse Sunshine configuration text into key-value entries.
    */
-  std::unordered_map<std::string, std::string> parse_config(const std::string_view &file_content) {
+  config_map_t parse_config(const std::string_view &file_content) {
-    std::unordered_map<std::string, std::string> vars;
+    config_map_t vars;
 
     auto pos = std::begin(file_content);
     auto end = std::end(file_content);
@@ -1081,7 +1081,7 @@ namespace config {
    * @param name Configuration key to consume.
    * @param destination Destination field updated when the setting exists and parses successfully.
    */
-  void string_f(std::unordered_map<std::string, std::string> &vars, const std::string &name, std::string &destination) {
+  void string_f(config_map_t &vars, const std::string &name, std::string &destination) {
     auto it = vars.find(name);
     if (it == std::end(vars)) {
       return;
@@ -1101,7 +1101,7 @@ namespace config {
    * @param f Converter applied to the raw configuration string.
    */
   template<typename T, typename F>
-  void generic_f(std::unordered_map<std::string, std::string> &vars, const std::string &name, T &destination, F &&f) {
+  void generic_f(config_map_t &vars, const std::string &name, T &destination, F &&f) {
     std::string tmp;
     string_f(vars, name, tmp);
     if (!tmp.empty()) {
@@ -1117,7 +1117,7 @@ namespace config {
    * @param destination Destination field updated when the setting exists and parses successfully.
    * @param allowed_vals Accepted string values for this setting.
    */
-  void string_restricted_f(std::unordered_map<std::string, std::string> &vars, const std::string &name, std::string &destination, const std::vector<std::string_view> &allowed_vals) {
+  void string_restricted_f(config_map_t &vars, const std::string &name, std::string &destination, const std::vector<std::string_view> &allowed_vals) {
     std::string temp;
     string_f(vars, name, temp);
 
@@ -1136,7 +1136,7 @@ namespace config {
    * @param name Setting name.
    * @param output Parsed string list.
    */
-  void string_list_f(std::unordered_map<std::string, std::string> &vars, const std::string &name, std::vector<std::string> &output) {  // NOSONAR(cpp:S6045): transparent hasher not available for unordered_map in this codebase
+  void string_list_f(config_map_t &vars, const std::string &name, std::vector<std::string> &output) {
     std::string temp;
     string_f(vars, name, temp);
 
@@ -1164,7 +1164,7 @@ namespace config {
    * @param name Configuration key to consume.
    * @param destination Destination field updated when the setting exists and parses successfully.
    */
-  void path_f(std::unordered_map<std::string, std::string> &vars, const std::string &name, fs::path &destination) {
+  void path_f(config_map_t &vars, const std::string &name, fs::path &destination) {
     // appdata needs to be retrieved once only
     static auto appdata = platf::appdata();
 
@@ -1195,7 +1195,7 @@ namespace config {
    * @param name Configuration key to consume.
    * @param destination Destination field updated when the setting exists and parses successfully.
    */
-  void path_f(std::unordered_map<std::string, std::string> &vars, const std::string &name, std::string &destination) {
+  void path_f(config_map_t &vars, const std::string &name, std::string &destination) {
     fs::path temp = destination;
 
     path_f(vars, name, temp);
@@ -1227,7 +1227,7 @@ namespace config {
    * @param name Configuration key to consume.
    * @param destination Destination field updated when the setting exists and parses successfully.
    */
-  void int_f(std::unordered_map<std::string, std::string> &vars, const std::string &name, int &destination) {
+  void int_f(config_map_t &vars, const std::string &name, int &destination) {
     auto it = vars.find(name);
 
     if (it == std::end(vars)) {
@@ -1245,7 +1245,7 @@ namespace config {
    * @param name Configuration key to consume.
    * @param destination Destination field updated when the setting exists and parses successfully.
    */
-  void int_f(std::unordered_map<std::string, std::string> &vars, const std::string &name, std::optional<int> &destination) {
+  void int_f(config_map_t &vars, const std::string &name, std::optional<int> &destination) {
     auto it = vars.find(name);
 
     if (it == std::end(vars)) {
@@ -1265,7 +1265,7 @@ namespace config {
    * @param f Converter applied to the raw configuration string.
    */
   template<class F>
-  void int_f(std::unordered_map<std::string, std::string> &vars, const std::string &name, int &destination, F &&f) {
+  void int_f(config_map_t &vars, const std::string &name, int &destination, F &&f) {
     std::string tmp;
     string_f(vars, name, tmp);
     if (!tmp.empty()) {
@@ -1282,7 +1282,7 @@ namespace config {
    * @param f Converter applied to the raw configuration string.
    */
   template<class F>
-  void int_f(std::unordered_map<std::string, std::string> &vars, const std::string &name, std::optional<int> &destination, F &&f) {
+  void int_f(config_map_t &vars, const std::string &name, std::optional<int> &destination, F &&f) {
     std::string tmp;
     string_f(vars, name, tmp);
     if (!tmp.empty()) {
@@ -1298,7 +1298,7 @@ namespace config {
    * @param destination Destination field updated when the setting exists and parses successfully.
    * @param range Inclusive range accepted for the parsed value.
    */
-  void int_between_f(std::unordered_map<std::string, std::string> &vars, const std::string &name, int &destination, const std::pair<int, int> &range) {
+  void int_between_f(config_map_t &vars, const std::string &name, int &destination, const std::pair<int, int> &range) {
     int temp = destination;
 
     int_f(vars, name, temp);
@@ -1335,7 +1335,7 @@ namespace config {
    * @param name Configuration key to consume.
    * @param destination Destination field updated when the setting exists and parses successfully.
    */
-  void bool_f(std::unordered_map<std::string, std::string> &vars, const std::string &name, bool &destination) {
+  void bool_f(config_map_t &vars, const std::string &name, bool &destination) {
     std::string tmp;
     string_f(vars, name, tmp);
 
@@ -1353,7 +1353,7 @@ namespace config {
    * @param name Configuration key to consume.
    * @param destination Destination field updated when the setting exists and parses successfully.
    */
-  void double_f(std::unordered_map<std::string, std::string> &vars, const std::string &name, double &destination) {
+  void double_f(config_map_t &vars, const std::string &name, double &destination) {
     std::string tmp;
     string_f(vars, name, tmp);
 
@@ -1379,7 +1379,7 @@ namespace config {
    * @param destination Destination field updated when the setting exists and parses successfully.
    * @param range Inclusive range accepted for the parsed value.
    */
-  void double_between_f(std::unordered_map<std::string, std::string> &vars, const std::string &name, double &destination, const std::pair<double, double> &range) {
+  void double_between_f(config_map_t &vars, const std::string &name, double &destination, const std::pair<double, double> &range) {
     double temp = destination;
 
     double_f(vars, name, temp);
@@ -1397,7 +1397,7 @@ namespace config {
    * @param name Configuration key to consume.
    * @param destination Destination field updated when the setting exists and parses successfully.
    */
-  void list_string_f(std::unordered_map<std::string, std::string> &vars, const std::string &name, std::vector<std::string> &destination) {
+  void list_string_f(config_map_t &vars, const std::string &name, std::vector<std::string> &destination) {
     std::string string;
     string_f(vars, name, string);
 
@@ -1443,7 +1443,7 @@ namespace config {
    * @param name Configuration key to consume.
    * @param destination Destination field updated when the setting exists and parses successfully.
    */
-  void list_prep_cmd_f(std::unordered_map<std::string, std::string> &vars, const std::string &name, std::vector<prep_cmd_t> &destination) {
+  void list_prep_cmd_f(config_map_t &vars, const std::string &name, std::vector<prep_cmd_t> &destination) {
     std::string string;
     string_f(vars, name, string);
 
@@ -1476,7 +1476,7 @@ namespace config {
    * @param name Configuration key to consume.
    * @param destination Destination field updated when the setting exists and parses successfully.
    */
-  void list_int_f(std::unordered_map<std::string, std::string> &vars, const std::string &name, std::vector<int> &destination) {
+  void list_int_f(config_map_t &vars, const std::string &name, std::vector<int> &destination) {
     std::vector<std::string> list;
     list_string_f(vars, name, list);
 
@@ -1516,7 +1516,7 @@ namespace config {
    * @param name Configuration key to consume.
    * @param destination Destination field updated when the setting exists and parses successfully.
    */
-  void map_int_int_f(std::unordered_map<std::string, std::string> &vars, const std::string &name, std::unordered_map<int, int> &destination) {
+  void map_int_int_f(config_map_t &vars, const std::string &name, std::unordered_map<int, int> &destination) {
     std::vector<int> list;
     list_int_f(vars, name, list);
 
@@ -1589,7 +1589,7 @@ namespace config {
   /**
    * @brief Log parsed configuration entries and optionally record them as modified.
    */
-  void log_config_settings(const std::unordered_map<std::string, std::string> &vars, bool save) {
+  void log_config_settings(const config_map_t &vars, bool save) {
     for (auto &[name, val] : vars) {
       bool is_redacted = std::ranges::find(config::redacted_config, name) != config::redacted_config.end();
 
@@ -1606,7 +1606,7 @@ namespace config {
    *
    * @param vars Parsed configuration entries; consumed keys are erased.
    */
-  void apply_config(std::unordered_map<std::string, std::string> &&vars) {
+  void apply_config(config_map_t &&vars) {
     log_config_settings(vars, true);
 
     int_f(vars, "qp", video.qp);
@@ -1973,7 +1973,7 @@ namespace config {
    * @brief Parse serialized text into the corresponding runtime representation.
    */
   int parse(int argc, char *argv[]) {
-    std::unordered_map<std::string, std::string> cmd_vars;
+    config_map_t cmd_vars;
 #ifdef _WIN32
     bool shortcut_launch = false;
     bool service_admin_launch = false;

src/config.h

@@ -15,8 +15,14 @@
 
 // local includes
 #include "nvenc/nvenc_config.h"
+#include "string_hash.h"
 
 namespace config {
+  /**
+   * @brief Owning configuration entries supporting lookup by string view or C string.
+   */
+  using config_map_t = std::unordered_map<std::string, std::string, util::transparent_string_hash, std::equal_to<>>;
+
   namespace nv {
     /**
      * @brief Convert Sunshine's NVENC quality preset number to FFmpeg's stable symbolic name.
@@ -39,7 +45,7 @@ namespace config {
   inline constexpr std::string_view GAMEPAD_DRIVER_NONE = "none";  ///< Disable virtual gamepads on Windows and macOS.
 
   // track modified config options
-  inline std::unordered_map<std::string, std::string> modified_config_settings;  ///< Configuration keys changed during the current parse or UI update.
+  inline config_map_t modified_config_settings;  ///< Configuration keys changed during the current parse or UI update.
 
   // sensitive values that should be redacted from logging
   /**
@@ -55,7 +61,7 @@ namespace config {
    * @param vars Parsed configuration entries to log.
    * @param save Whether modified configuration values should be written back to disk.
    */
-  void log_config_settings(const std::unordered_map<std::string, std::string> &vars, bool save);
+  void log_config_settings(const config_map_t &vars, bool save);
 
   /**
    * @brief Video encoder, capture, and color settings loaded from configuration.
@@ -427,7 +433,7 @@ namespace config {
    * @param file_content Raw configuration file contents to parse.
    * @return Parsed configuration key-value entries.
    */
-  std::unordered_map<std::string, std::string> parse_config(const std::string_view &file_content);
+  config_map_t parse_config(const std::string_view &file_content);
 
   /**
    * @brief Persist a configuration option when the active file does not already define it.

src/confighttp.h

@@ -274,7 +274,7 @@ namespace confighttp {
 /**
  * @brief File-extension to MIME-type mapping used when serving the Web UI.
  */
-const std::map<std::string, std::string> mime_types = {
+const std::map<std::string, std::string, std::less<>> mime_types = {
   {"css", "text/css"},
   {"gif", "image/gif"},
   {"htm", "text/html"},

src/input.cpp

@@ -2109,7 +2109,7 @@ namespace input {
     // the input to the OS. This avoids potentially lengthy lock contention
     // in the control stream thread while input is being processed by the OS.
     {
-      std::lock_guard<std::mutex> lg(input->input_queue_lock);
+      std::scoped_lock lg(input->input_queue_lock);
 
       // If all entries have already been processed, nothing to do
       if (input->input_queue.empty()) {

src/logging.cpp

@@ -7,6 +7,7 @@
 #include <fstream>
 #include <iomanip>
 #include <iostream>
+#include <utility>
 
 // lib includes
 #include <boost/core/null_deleter.hpp>
@@ -226,8 +227,8 @@ namespace logging {
   }
 
   void setup_libdisplaydevice_logging(int min_log_level) {
-    constexpr int min_level {static_cast<int>(display_device::Logger::LogLevel::verbose)};
+    constexpr int min_level {std::to_underlying(display_device::Logger::LogLevel::verbose)};
-    constexpr int max_level {static_cast<int>(display_device::Logger::LogLevel::fatal)};
+    constexpr int max_level {std::to_underlying(display_device::Logger::LogLevel::fatal)};
     const auto log_level {static_cast<display_device::Logger::LogLevel>(std::min(std::max(min_level, min_log_level), max_level))};
 
     display_device::Logger::get().setLogLevel(log_level);

src/logging.h

@@ -123,8 +123,9 @@ namespace logging {
   void setup_av_logging(int min_log_level);
 
   /**
-   * @brief Setup logging for libdisplaydevice.
+   * @brief Set up libdisplaydevice logging, clamping to its supported enum values.
-   * @param min_log_level The log level.
+   *
+   * @param min_log_level Numeric minimum severity, clamped from verbose through fatal.
    */
   void setup_libdisplaydevice_logging(int min_log_level);
 

src/network.cpp

@@ -18,15 +18,15 @@ namespace ip = boost::asio::ip;
 
 namespace net {
   /**
-   * @brief Pc ips v4.
+   * @brief IPv4 loopback networks used for local-client classification.
    */
-  std::vector<ip::network_v4> pc_ips_v4 {
+  std::vector pc_ips_v4 {
     ip::make_network_v4("127.0.0.0/8"sv),
   };
   /**
-   * @brief Lan ips v4.
+   * @brief IPv4 private and link-local networks used for LAN classification.
    */
-  std::vector<ip::network_v4> lan_ips_v4 {
+  std::vector lan_ips_v4 {
     ip::make_network_v4("192.168.0.0/16"sv),
     ip::make_network_v4("172.16.0.0/12"sv),
     ip::make_network_v4("10.0.0.0/8"sv),
@@ -35,15 +35,15 @@ namespace net {
   };
 
   /**
-   * @brief Pc ips v6.
+   * @brief IPv6 loopback networks used for local-client classification.
    */
-  std::vector<ip::network_v6> pc_ips_v6 {
+  std::vector pc_ips_v6 {
     ip::make_network_v6("::1/128"sv),
   };
   /**
-   * @brief Lan ips v6.
+   * @brief IPv6 private and link-local networks used for LAN classification.
    */
-  std::vector<ip::network_v6> lan_ips_v6 {
+  std::vector lan_ips_v6 {
     ip::make_network_v6("fc00::/7"sv),
     ip::make_network_v6("fe80::/64"sv),
   };

src/nvhttp.cpp

@@ -35,6 +35,7 @@
 #include "platform/common.h"
 #include "process.h"
 #include "rtsp.h"
+#include "string_hash.h"
 #include "system_tray.h"
 #include "utility.h"
 #include "uuid.h"
@@ -191,7 +192,7 @@ namespace nvhttp {
   };
 
   // uniqueID, session
-  std::unordered_map<std::string, pair_session_t> map_id_sess;  ///< Pairing sessions keyed by temporary unique ID.
+  std::unordered_map<std::string, pair_session_t, util::transparent_string_hash, std::equal_to<>> map_id_sess;  ///< Pairing sessions keyed by temporary unique ID.
 
   /**
    * @brief Get the mutex protecting pairing-session state.

src/platform/linux/cuda.cpp

@@ -8,6 +8,7 @@
 #include <fcntl.h>
 #include <filesystem>
 #include <thread>
+#include <utility>
 
 // lib includes
 #include <ffnvcodec/dynlink_loader.h>
@@ -363,7 +364,7 @@ namespace cuda {
     BOOST_LOG(debug) << "Found CUDA device with PCI bus ID: "sv << pci_bus_id.data();
 
     // Linux uses lowercase hexadecimal while CUDA uses uppercase
-    std::transform(pci_bus_id.begin(), pci_bus_id.end(), pci_bus_id.begin(), [](char c) {
+    std::ranges::transform(pci_bus_id, pci_bus_id.begin(), [](char c) {
       return std::tolower(c);
     });
 
@@ -1063,7 +1064,7 @@ namespace cuda {
               }
               break;
             default:
-              BOOST_LOG(error) << "Unrecognized capture status ["sv << (int) status << ']';
+              BOOST_LOG(error) << "Unrecognized capture status ["sv << std::to_underlying(status) << ']';
               return status;
           }
         }

src/platform/linux/graphics.cpp

@@ -7,6 +7,7 @@
 #include <fcntl.h>
 #include <future>
 #include <stdexcept>
+#include <string_view>
 
 // local includes
 #include "graphics.h"
@@ -557,7 +558,7 @@ namespace egl {
     };
 
     for (auto ext : extensions) {
-      if (!std::strstr(extension_st, ext)) {
+      if (!std::string_view {extension_st}.contains(ext)) {
         BOOST_LOG(error) << "Missing extension: ["sv << ext << ']';
         return nullptr;
       }

src/platform/linux/kmsgrab.cpp

@@ -12,6 +12,7 @@
 #include <stdexcept>
 #include <thread>
 #include <unistd.h>
+#include <utility>
 
 // platform includes
 #include <drm_fourcc.h>
@@ -1831,7 +1832,7 @@ namespace platf {
               }
               break;
             default:
-              BOOST_LOG(error) << "Unrecognized capture status ["sv << (int) status << ']';
+              BOOST_LOG(error) << "Unrecognized capture status ["sv << std::to_underlying(status) << ']';
               return status;
           }
         }
@@ -2107,7 +2108,7 @@ namespace platf {
               }
               break;
             default:
-              BOOST_LOG(error) << "Unrecognized capture status ["sv << (int) status << ']';
+              BOOST_LOG(error) << "Unrecognized capture status ["sv << std::to_underlying(status) << ']';
               return status;
           }
         }

src/platform/linux/misc.cpp

@@ -20,6 +20,7 @@
 #include <iomanip>
 #include <iostream>
 #include <sstream>
+#include <utility>
 
 // platform includes
 #include <arpa/inet.h>
@@ -1020,7 +1021,7 @@ namespace platf {
   // We can't track QoS state separately for each destination on this OS,
   // so we keep a ref count to only disable QoS options when all clients
   // are disconnected.
-  static std::atomic<int> qos_ref_count = 0;
+  static std::atomic qos_ref_count = 0;
 
   /**
    * @brief Linux QoS state used to tune socket priority while streaming.
@@ -1086,7 +1087,7 @@ namespace platf {
           dscp = 48;
           break;
         default:
-          BOOST_LOG(error) << "Unknown traffic type: "sv << (int) data_type;
+          BOOST_LOG(error) << "Unknown traffic type: "sv << std::to_underlying(data_type);
           break;
       }
 

src/platform/linux/portalgrab.cpp

@@ -1081,7 +1081,7 @@ namespace portal {
     dbus_t dbus;  ///< DBus connection used for portal screencast requests.
 
     // Class variable to store runtime state of maxFramerate negotiation
-    static inline std::atomic<bool> negotiate_maxframerate {true};  ///< Whether portal negotiation should request the maximum frame rate.
+    static inline std::atomic negotiate_maxframerate {true};  ///< Whether portal negotiation should request the maximum frame rate.
   };
 }  // namespace portal
 

src/platform/linux/x11grab.cpp

@@ -9,6 +9,7 @@
 #include <fstream>
 #include <ranges>
 #include <thread>
+#include <utility>
 
 #ifdef SUNSHINE_TESTS
   #include <gtest/gtest.h>
@@ -630,7 +631,7 @@ namespace platf {
             }
             break;
           default:
-            BOOST_LOG(error) << "Unrecognized capture status ["sv << (int) status << ']';
+            BOOST_LOG(error) << "Unrecognized capture status ["sv << std::to_underlying(status) << ']';
             return status;
         }
       }
@@ -804,7 +805,7 @@ namespace platf {
             }
             break;
           default:
-            BOOST_LOG(error) << "Unrecognized capture status ["sv << (int) status << ']';
+            BOOST_LOG(error) << "Unrecognized capture status ["sv << std::to_underlying(status) << ']';
             return status;
         }
       }

src/platform/windows/audio.cpp

@@ -120,7 +120,7 @@ namespace {
         break;
     }
 
-    static_assert((int) sample_format_e::_size == 5, "Unrecognized sample_format_e");
+    static_assert(std::to_underlying(sample_format_e::_size) == 5, "Unrecognized sample_format_e");
 
     waveformat.Format.wFormatTag = WAVE_FORMAT_EXTENSIBLE;
     waveformat.Format.nChannels = channel_count;

src/platform/windows/display_base.cpp

@@ -6,6 +6,7 @@
 #include <array>
 #include <cmath>
 #include <thread>
+#include <utility>
 
 // platform includes
 #include <initguid.h>
@@ -353,7 +354,7 @@ namespace platf::dxgi {
           }
           break;
         default:
-          BOOST_LOG(error) << "Unrecognized capture status ["sv << (int) status << ']';
+          BOOST_LOG(error) << "Unrecognized capture status ["sv << std::to_underlying(status) << ']';
           return status;
       }
 
@@ -1137,7 +1138,7 @@ namespace platf {
   bool needs_encoder_reenumeration() {
     // Serialize access to the static DXGI factory
     static std::mutex reenumeration_state_lock;
-    auto lg = std::lock_guard(reenumeration_state_lock);
+    auto lg = std::scoped_lock(reenumeration_state_lock);
 
     // Keep a reference to the DXGI factory, which will keep track of changes internally.
     static dxgi::factory1_t factory;

src/platform/windows/display_vram.cpp

@@ -3,8 +3,10 @@
  * @brief Definitions for handling video ram.
  */
 // standard includes
+#include <algorithm>
 #include <array>
 #include <cmath>
+#include <span>
 
 // platform includes
 #include <d3dcompiler.h>
@@ -286,7 +288,7 @@ namespace platf::dxgi {
       case DXGI_OUTDUPL_POINTER_SHAPE_TYPE_MASKED_COLOR:
         {
           util::buffer_t<std::uint8_t> cursor_img = img_data;
-          std::for_each((std::uint32_t *) std::begin(cursor_img), (std::uint32_t *) std::end(cursor_img), [](auto &pixel) {
+          std::ranges::for_each(std::span {(std::uint32_t *) std::begin(cursor_img), (std::uint32_t *) std::end(cursor_img)}, [](auto &pixel) {
             auto alpha = (std::uint8_t) ((pixel >> 24) & 0xFF);
             if (alpha == 0xFF) {
               // Pixels with 0xFF alpha will be XOR-blended as is.
@@ -360,7 +362,7 @@ namespace platf::dxgi {
       case DXGI_OUTDUPL_POINTER_SHAPE_TYPE_MASKED_COLOR:
         {
           util::buffer_t<std::uint8_t> cursor_img = img_data;
-          std::for_each((std::uint32_t *) std::begin(cursor_img), (std::uint32_t *) std::end(cursor_img), [](auto &pixel) {
+          std::ranges::for_each(std::span {(std::uint32_t *) std::begin(cursor_img), (std::uint32_t *) std::end(cursor_img)}, [](auto &pixel) {
             auto alpha = (std::uint8_t) ((pixel >> 24) & 0xFF);
             if (alpha == 0xFF) {
               // Pixels with 0xFF alpha will be XOR-blended by make_cursor_xor_image().

src/platform/windows/misc.cpp

@@ -10,12 +10,14 @@
 #include <iterator>
 #include <set>
 #include <sstream>
+#include <utility>
 #include <vector>
 
 // lib includes
 #include <boost/algorithm/string.hpp>
 #include <boost/asio/ip/address.hpp>
 #include <boost/program_options/parsers.hpp>
+#include <boost/range/algorithm/find_if.hpp>
 
 // local includes required before platform includes
 #include "src/boost_process_compat.h"
@@ -100,7 +102,7 @@ extern "C" {
 
 namespace {
 
-  std::atomic<bool> used_nt_set_timer_resolution = false;
+  std::atomic used_nt_set_timer_resolution = false;
 
   bool nt_set_timer_resolution_max() {
     ULONG maximum;
@@ -375,6 +377,8 @@ namespace platf {
   /**
    * @brief Merge user environment variables into a Windows environment block.
    *
+   * Existing variable names retain their spelling when matched case-insensitively.
+   *
    * @param env Environment variables for the child process.
    * @param shell_token Shell token.
    * @return True when the user environment block was merged into `env`.
@@ -394,7 +398,7 @@ namespace platf {
       std::string env_val = env_tuple.substr(env_tuple.find('=') + 1);
 
       // Perform a case-insensitive search to see if this variable name already exists
-      if (auto itr = std::find_if(env.begin(), env.end(), [&](const auto &e) {
+      if (auto itr = boost::range::find_if(env, [&env_name](const auto &e) {
             return boost::iequals(e.get_name(), env_name);
           });
           itr != env.end()) {
@@ -829,7 +833,7 @@ namespace platf {
       // Overriding these predefined keys affects process-wide state, so serialize all calls
       // to ensure the handle state is consistent while we perform the command query.
       static std::mutex per_user_key_mutex;
-      auto lg = std::lock_guard(per_user_key_mutex);
+      auto lg = std::scoped_lock(per_user_key_mutex);
 
       // Override HKEY_CLASSES_ROOT and HKEY_CURRENT_USER to ensure we query the correct class info
       if (!override_per_user_predefined_keys(token)) {
@@ -1027,7 +1031,7 @@ namespace platf {
     auto sunshine_wenv = boost::this_process::wenvironment();
     std::wstring path_var_name {L"PATH"};
     std::wstring old_path_val;
-    auto itr = std::find_if(sunshine_wenv.cbegin(), sunshine_wenv.cend(), [&](const auto &e) {
+    auto itr = boost::range::find_if(std::as_const(sunshine_wenv), [&path_var_name](const auto &e) {
       return boost::iequals(e.get_name(), path_var_name);
     });
     if (itr != sunshine_wenv.cend()) {
@@ -1144,7 +1148,7 @@ namespace platf {
         win32_priority = THREAD_PRIORITY_HIGHEST;
         break;
       default:
-        BOOST_LOG(error) << "Unknown thread priority: "sv << (int) priority;
+        BOOST_LOG(error) << "Unknown thread priority: "sv << std::to_underlying(priority);
         return;
     }
 
@@ -1749,7 +1753,7 @@ namespace platf {
         traffic_type = QOSTrafficTypeAudioVideo;
         break;
       default:
-        BOOST_LOG(error) << "Unknown traffic type: "sv << (int) data_type;
+        BOOST_LOG(error) << "Unknown traffic type: "sv << std::to_underlying(data_type);
         return nullptr;
     }
 

src/process.cpp

@@ -5,10 +5,12 @@
 #define BOOST_BIND_GLOBAL_PLACEHOLDERS
 
 // standard includes
+#include <algorithm>
 #include <array>
 #include <filesystem>
 #include <string>
 #include <thread>
+#include <utility>
 #include <vector>
 
 // lib includes
@@ -18,6 +20,7 @@
 #include <boost/program_options/parsers.hpp>
 #include <boost/property_tree/json_parser.hpp>
 #include <boost/property_tree/ptree.hpp>
+#include <boost/range/algorithm/find_if.hpp>
 #include <boost/token_functions.hpp>
 #include <openssl/evp.h>
 #include <openssl/sha.h>
@@ -130,7 +133,7 @@ namespace proc {
     BOOST_LOG(debug) << "Parsed target ["sv << parts.at(0) << "] from command ["sv << cmd << ']';
 
     // If the target is a URL, don't parse any further here
-    if (parts.at(0).find("://") != std::string::npos) {
+    if (parts.at(0).contains("://")) {
       return boost::filesystem::path();
     }
 
@@ -495,7 +498,7 @@ namespace proc {
               // Windows treats environment variable names in a case-insensitive manner,
               // so we look for a case-insensitive match here. This is critical for
               // correctly appending to PATH on Windows.
-              auto itr = std::find_if(env.cbegin(), env.cend(), [&](const auto &e) {
+              auto itr = boost::range::find_if(std::as_const(env), [&var_name](const auto &e) {
                 return boost::iequals(e.get_name(), var_name);
               });
               if (itr != env.cend()) {
@@ -715,7 +718,7 @@ namespace proc {
         this_env[name] = parse_env_val(this_env, val.get_value<std::string>());
       }
 
-      std::set<std::string> ids;
+      std::set<std::string, std::less<>> ids;
       std::vector<proc::ctx_t> apps;
       int i = 0;
       for (auto &[_, app_node] : apps_node) {

src/rtsp.cpp

@@ -375,7 +375,7 @@ namespace rtsp_stream {
           // If content_length > bytes read, then we need to store current data read,
           // to be appended by the next read.
           std::string_view content {option->content};
-          auto begin = std::find_if(std::begin(content), std::end(content), [](auto ch) {
+          auto begin = std::ranges::find_if(content, [](auto ch) {
             return (bool) std::isdigit(ch);
           });
 
@@ -1019,7 +1019,7 @@ namespace rtsp_stream {
     seqn.content = const_cast<char *>(seqn_str.c_str());
 
     std::string_view target {req->message.request.target};
-    auto begin = std::find(std::begin(target), std::end(target), '=') + 1;
+    auto begin = std::ranges::find(target, '=') + 1;
     auto end = std::find(begin, std::end(target), '/');
     std::string_view type {begin, (size_t) std::distance(begin, end)};
 
@@ -1220,7 +1220,7 @@ namespace rtsp_stream {
         if ("Host"sv == request_option->option) {
           std::string_view content {request_option->content};
           BOOST_LOG(debug) << "Found Host: "sv << content;
-          config.audio.flags[audio::config_t::HIGH_QUALITY] = (content.find("0.0.0.0"sv) == std::string::npos);
+          config.audio.flags[audio::config_t::HIGH_QUALITY] = !content.contains("0.0.0.0"sv);
         }
       }
     } else if (session.surround_params.length() > 3) {

src/stream.cpp

@@ -367,7 +367,7 @@ namespace stream {
   static inline int encode_audio(bool encrypted, const audio::buffer_t &plaintext, uint8_t *destination, crypto::aes_t &iv, crypto::cipher::cbc_t &cbc) {
     // If encryption isn't enabled
     if (!encrypted) {
-      std::copy(std::begin(plaintext), std::end(plaintext), destination);
+      std::ranges::copy(plaintext, destination);
       return (int) plaintext.size();
     }
 
@@ -1000,7 +1000,7 @@ namespace stream {
 
     std::copy(begin, next, std::back_inserter(replaced));
     if (next != end) {
-      std::copy(std::begin(_new), std::end(_new), std::back_inserter(replaced));
+      std::ranges::copy(_new, std::back_inserter(replaced));
       std::copy(next + old.size(), end, std::back_inserter(replaced));
     }
 
@@ -2116,7 +2116,7 @@ namespace stream {
       }
 
       TUPLE_2D_REF(recv_peer, msg, *msg_opt);
-      if (msg.find(expected_payload) != std::string::npos) {
+      if (msg.contains(expected_payload)) {
         // Match the new PING payload format
         BOOST_LOG(debug) << "Received ping [v2] from "sv << recv_peer.address() << ':' << recv_peer.port() << " ["sv << util::hex_vec(msg) << ']';
       } else if (!(session->config.mlFeatureFlags & ML_FF_SESSION_ID_V1) && msg == "PING"sv) {

src/string_hash.h

@@ -0,0 +1,29 @@
+/**
+ * @file src/string_hash.h
+ * @brief Transparent hashing for containers with owning string keys.
+ */
+#pragma once
+
+// standard includes
+#include <cstddef>
+#include <functional>
+#include <string_view>
+
+namespace util {
+  /**
+   * @brief Hash strings, string views, and C strings without temporary allocations.
+   */
+  struct transparent_string_hash {
+    using is_transparent = void;  ///< Enable heterogeneous unordered-container lookup.
+
+    /**
+     * @brief Hash all characters in a string-like key, including embedded nulls in views.
+     *
+     * @param value Text to hash.
+     * @return Hash shared by equivalent owning and non-owning string keys.
+     */
+    std::size_t operator()(std::string_view value) const noexcept {
+      return std::hash<std::string_view> {}(value);
+    }
+  };
+}  // namespace util

src/sync.h

@@ -29,10 +29,10 @@ namespace sync_util {
     /**
      * @brief Acquire the underlying lock or keyed mutex.
      *
-     * @return Lock guard owning the synchronized object until destruction.
+     * @return Scoped lock owning the synchronized object until destruction.
      */
-    std::lock_guard<mutex_t> lock() {
+    std::scoped_lock<mutex_t> lock() {
-      return std::lock_guard {_lock};
+      return std::scoped_lock {_lock};
     }
 
     /**

src/system_tray.cpp

@@ -77,6 +77,7 @@
   #include "platform/common.h"
   #include "process.h"
   #include "src/entry_handler.h"
+  #include "string_hash.h"
   #include "system_tray.h"
   #include "thread_safe.h"
   #ifdef _WIN32
@@ -118,23 +119,6 @@ namespace system_tray {
       return worker;
     }
 
-    /**
-     * @brief Hash string-like resource paths without allocating temporary strings.
-     */
-    struct transparent_string_hash_t {
-      using is_transparent = void;  ///< Enable heterogeneous unordered-map lookup.
-
-      /**
-       * @brief Hash a string view.
-       *
-       * @param value String view to hash.
-       * @return Hash value for the supplied text.
-       */
-      std::size_t operator()(const std::string_view value) const noexcept {
-        return std::hash<std::string_view> {}(value);
-      }
-    };
-
   #if defined(_WIN32) || defined(__APPLE__)
     /**
      * @brief Access storage for dynamic Virtual HID Broker license menu labels.
@@ -629,7 +613,7 @@ namespace system_tray {
 
   #if defined(_WIN32) || defined(__APPLE__)
     // Simple cache ensures our string pointers live forever.
-    static std::unordered_map<std::string, std::string, transparent_string_hash_t, std::equal_to<>> g_cache;
+    static std::unordered_map<std::string, std::string, util::transparent_string_hash, std::equal_to<>> g_cache;
     auto search = g_cache.find(std::string_view {relativePath});
     if (search != g_cache.end()) {
       return search->second.c_str();

src/task_pool.h

@@ -154,7 +154,7 @@ namespace task_pool_util {
 
       auto future = task.get_future();
 
-      std::lock_guard<std::mutex> lg(_task_mutex);
+      std::scoped_lock lg(_task_mutex);
       _tasks.emplace_back(toRunnable(std::move(task)));
 
       return future;
@@ -166,7 +166,7 @@ namespace task_pool_util {
      * @param task Task object to enqueue or execute.
      */
     void pushDelayed(std::pair<__time_point, __task> &&task) {
-      std::lock_guard lg(_task_mutex);
+      std::scoped_lock lg(_task_mutex);
 
       auto it = _timer_tasks.cbegin();
       for (; it < _timer_tasks.cend(); ++it) {
@@ -221,7 +221,7 @@ namespace task_pool_util {
      */
     template<class X, class Y>
     void delay(task_id_t task_id, std::chrono::duration<X, Y> duration) {
-      std::lock_guard<std::mutex> lg(_task_mutex);
+      std::scoped_lock lg(_task_mutex);
 
       auto it = _timer_tasks.begin();
       for (; it < _timer_tasks.cend(); ++it) {
@@ -257,7 +257,7 @@ namespace task_pool_util {
      * @return True when the task was found and cancelled.
      */
     bool cancel(task_id_t task_id) {
-      std::lock_guard lg(_task_mutex);
+      std::scoped_lock lg(_task_mutex);
 
       auto it = _timer_tasks.begin();
       for (; it < _timer_tasks.cend(); ++it) {
@@ -280,9 +280,9 @@ namespace task_pool_util {
      * @return Removed queue item, or empty result when the queue is stopped or empty.
      */
     std::optional<std::pair<__time_point, __task>> pop(task_id_t task_id) {
-      std::lock_guard lg(_task_mutex);
+      std::scoped_lock lg(_task_mutex);
 
-      auto pos = std::find_if(std::begin(_timer_tasks), std::end(_timer_tasks), [&task_id](const auto &t) {
+      auto pos = std::ranges::find_if(_timer_tasks, [&task_id](const auto &t) {
         return t.second.get() == task_id;
       });
 
@@ -299,7 +299,7 @@ namespace task_pool_util {
      * @return Removed queue item, or empty result when the queue is stopped or empty.
      */
     std::optional<__task> pop() {
-      std::lock_guard lg(_task_mutex);
+      std::scoped_lock lg(_task_mutex);
 
       if (!_tasks.empty()) {
         __task task = std::move(_tasks.front());
@@ -322,7 +322,7 @@ namespace task_pool_util {
      * @return True when the task was found and cancelled.
      */
     bool ready() {
-      std::lock_guard<std::mutex> lg(_task_mutex);
+      std::scoped_lock lg(_task_mutex);
 
       return !_tasks.empty() || (!_timer_tasks.empty() && std::get<0>(_timer_tasks.back()) <= std::chrono::steady_clock::now());
     }
@@ -333,7 +333,7 @@ namespace task_pool_util {
      * @return Time point for the next queued timer task, or std::nullopt when none exist.
      */
     std::optional<__time_point> next() {
-      std::lock_guard<std::mutex> lg(_task_mutex);
+      std::scoped_lock lg(_task_mutex);
 
       if (_timer_tasks.empty()) {
         return std::nullopt;

src/utility.h

@@ -640,7 +640,7 @@ namespace util {
       return ('a' <= ch && ch <= 'z') || ('A' <= ch && ch <= 'Z');
     };
 
-    auto buf_size = std::count_if(std::begin(hex), std::end(hex), is_convertable) / 2;
+    auto buf_size = std::ranges::count_if(hex, is_convertable) / 2;
     auto padding = sizeof(T) - buf_size;
 
     const char *data = hex.data() + hex.size() - 1;
@@ -671,7 +671,7 @@ namespace util {
     });
 
     if (rev) {
-      std::reverse(std::begin(buf), std::end(buf));
+      std::ranges::reverse(buf);
     }
 
     return std::bit_cast<T>(buf);
@@ -695,7 +695,7 @@ namespace util {
       return ('a' <= ch && ch <= 'z') || ('A' <= ch && ch <= 'Z');
     };
 
-    auto buf_size = std::count_if(std::begin(hex), std::end(hex), is_convertable) / 2;
+    auto buf_size = std::ranges::count_if(hex, is_convertable) / 2;
     buf.resize(buf_size);
 
     const char *data = hex.data() + hex.size() - 1;
@@ -724,7 +724,7 @@ namespace util {
     }
 
     if (rev) {
-      std::reverse(std::begin(buf), std::end(buf));
+      std::ranges::reverse(buf);
     }
 
     return buf;
@@ -1477,14 +1477,14 @@ namespace util {
     }
 
     /**
-     * @brief Construct an owning contiguous buffer.
+     * @brief Copy the source buffer's logical range into an independent allocation.
      *
      * @param o Source object used for comparison or assignment.
      */
     buffer_t(const buffer_t &o):
         _els {o._els},
         _buf(_els) {
-      std::copy(o.begin(), o.end(), begin());
+      std::ranges::copy(o, begin());
     }
 
     /**

src/uuid.h

@@ -77,12 +77,12 @@ namespace uuid_util {
       auto last_slice = hex_view.substr(20, 12);
 
       for (auto &slice : slices) {
-        std::copy(std::begin(slice), std::end(slice), std::back_inserter(result));
+        std::ranges::copy(slice, std::back_inserter(result));
 
         result.push_back('-');
       }
 
-      std::copy(std::begin(last_slice), std::end(last_slice), std::back_inserter(result));
+      std::ranges::copy(last_slice, std::back_inserter(result));
 
       return result;
     }

tests/tests_log_checker.h

@@ -96,7 +96,7 @@ namespace log_checker {
   }
 
   /**
-   * @brief Check if a log file contains a line that contains the given substring.
+   * @brief Check whether any log line contains the substring, including an empty substring.
    * @param log_file Path to the log file.
    * @param substr The substring to search for.
    * @param case_insensitive Whether the search should be case-insensitive.
@@ -122,7 +122,7 @@ namespace log_checker {
         // sonarcloud complains about this, but the solution doesn't work for macOS-12
         std::transform(line.begin(), line.end(), line.begin(), ::tolower);
       }
-      if (line.find(search_str) != std::string::npos) {
+      if (line.contains(search_str)) {
         return true;
       }
     }

tests/unit/platform/windows/test_display_vram.cpp

@@ -8,6 +8,7 @@
 
 #ifdef _WIN32
   // standard includes
+  #include <algorithm>
   #include <array>
   #include <bit>
   #include <cstdint>
@@ -87,6 +88,27 @@ TEST(WindowsCursorTest, StopsAtTheLastPixelInAPartialMaskByte) {
   }));
 }
 
+TEST(WindowsCursorTest, ProcessesEveryMaskedColorPixelAndPreservesTheInput) {
+  const std::array<std::uint32_t, 3> pixels {0xFF112233, 0x00123456, 0x7F445566};
+  const auto bytes = std::bit_cast<std::array<std::uint8_t, 12>>(pixels);
+  util::buffer_t<std::uint8_t> input {bytes.size()};
+  std::ranges::copy(bytes, input.begin());
+  const DXGI_OUTDUPL_POINTER_SHAPE_INFO shape {
+    .Type = DXGI_OUTDUPL_POINTER_SHAPE_TYPE_MASKED_COLOR,
+    .Width = 3,
+    .Height = 1,
+    .Pitch = 12,
+  };
+
+  const auto alpha = platf::dxgi::make_cursor_alpha_image(input, shape);
+  const auto xor_image = platf::dxgi::make_cursor_xor_image(input, shape);
+  const std::array<std::uint32_t, 3> expected_alpha {0, 0xFF123456, 0x7F445566};
+  const std::array<std::uint32_t, 3> expected_xor {0xFF112233, 0, 0x7F445566};
+  EXPECT_TRUE((std::ranges::equal(alpha, std::bit_cast<std::array<std::uint8_t, 12>>(expected_alpha))));
+  EXPECT_TRUE((std::ranges::equal(xor_image, std::bit_cast<std::array<std::uint8_t, 12>>(expected_xor))));
+  EXPECT_TRUE(std::ranges::equal(input, bytes));
+}
+
 using platf::dxgi::fp16_transfer_e;
 using platf::dxgi::select_fp16_transfer;
 

tests/unit/test_config.cpp

@@ -20,6 +20,20 @@
 
 using namespace std::literals;
 
+TEST(ConfigParsingTest, ParsedEntriesOwnKeysAndSupportStringViewLookup) {
+  std::string input = "encoder = software\nencoder = nvenc\n";
+  const auto entries = config::parse_config(input);
+  input.assign(input.size(), 'x');
+
+  const std::string padded = "__encoder__";
+  const auto key = std::string_view {padded}.substr(2, 7);
+  const auto found = entries.find(key);
+  ASSERT_NE(found, entries.end());
+  EXPECT_EQ(found->second, "software");
+  EXPECT_FALSE(entries.contains("missing"sv));
+  EXPECT_EQ(entries.size(), 1);
+}
+
 TEST(ConfigDefaultsTest, UsesAutomaticGamepadSelection) {
   EXPECT_EQ(config::input.gamepad, "auto");
 }
@@ -28,6 +42,19 @@ TEST(ConfigDefaultsTest, TreatsFp16SdrCapturesAsLinear) {
   EXPECT_FALSE(config::video.fp16_sdr_gamma_encoded);
 }
 
+TEST(ConfigDefaultsTest, PreservesAmdEncoderNumericDefaults) {
+  EXPECT_EQ(config::video.amd.amd_usage_h264, 1);
+  EXPECT_EQ(config::video.amd.amd_usage_hevc, 1);
+  EXPECT_EQ(config::video.amd.amd_usage_av1, 2);
+  EXPECT_EQ(config::video.amd.amd_rc_h264, 3);
+  EXPECT_EQ(config::video.amd.amd_rc_hevc, 1);
+  EXPECT_EQ(config::video.amd.amd_rc_av1, 1);
+  EXPECT_EQ(config::video.amd.amd_quality_h264, 0);
+  EXPECT_EQ(config::video.amd.amd_quality_hevc, 5);
+  EXPECT_EQ(config::video.amd.amd_quality_av1, 70);
+  EXPECT_EQ(config::video.amd.amd_coder, 0);
+}
+
 using NvencPresetNameParam = std::pair<int, std::string_view>;
 
 /**

tests/unit/test_logging.cpp

@@ -127,6 +127,18 @@ TEST_F(LogRotationTest, ReportsFilesystemErrors) {
   EXPECT_EQ(read_log_file(log_path), "current");
 }
 
+TEST_F(LogRotationTest, FindsSubstringsAtBoundariesAndWithCaseFolding) {
+  write_log_file(log_path, "prefix middle suffix\nMiXeD\n\n");
+  const auto path = log_path.string();
+  EXPECT_TRUE(log_checker::line_contains(path, "prefix"));
+  EXPECT_TRUE(log_checker::line_contains(path, "middle"));
+  EXPECT_TRUE(log_checker::line_contains(path, "suffix"));
+  EXPECT_TRUE(log_checker::line_contains(path, ""));
+  EXPECT_TRUE(log_checker::line_contains(path, "mixed", true));
+  EXPECT_FALSE(log_checker::line_contains(path, "mixed"));
+  EXPECT_FALSE(log_checker::line_contains(path, "absent"));
+}
+
 struct LogLevelsTest: BaseTest, testing::WithParamInterface<decltype(log_levels)::value_type> {};
 
 INSTANTIATE_TEST_SUITE_P(

tests/unit/test_network.cpp

@@ -9,6 +9,18 @@
 // local includes
 #include <src/network.h>
 
+TEST(NetworkClassificationTest, DeducedNetworkListsPreserveAddressScopes) {
+  EXPECT_EQ(net::from_address("127.0.0.1"), net::PC);
+  EXPECT_EQ(net::from_address("192.168.1.2"), net::LAN);
+  EXPECT_EQ(net::from_address("100.64.0.1"), net::LAN);
+  EXPECT_EQ(net::from_address("169.254.1.2"), net::LAN);
+  EXPECT_EQ(net::from_address("8.8.8.8"), net::WAN);
+  EXPECT_EQ(net::from_address("::1"), net::PC);
+  EXPECT_EQ(net::from_address("fc00::1"), net::LAN);
+  EXPECT_EQ(net::from_address("fe80::1"), net::LAN);
+  EXPECT_EQ(net::from_address("2001:4860:4860::8888"), net::WAN);
+}
+
 struct MdnsInstanceNameTest: BaseTest, testing::WithParamInterface<std::tuple<std::string, std::string>> {};
 
 TEST_P(MdnsInstanceNameTest, Run) {

tests/unit/test_process.cpp

@@ -15,9 +15,57 @@
 
 // local includes
 #include <src/process.h>
+#include <src/utility.h>
 
 namespace fs = std::filesystem;
 
+namespace proc {
+  /**
+   * @brief Resolve a command's working directory, returning an empty path for URLs.
+   *
+   * @param cmd Command line to inspect.
+   * @param env Environment used for executable lookup.
+   * @return Working directory, or an empty path when the command is a URL.
+   */
+  boost::filesystem::path find_working_directory(const std::string &cmd, boost::process::v1::environment &env);
+
+  /**
+   * @brief Expand environment references while preserving Windows variable-name casing.
+   *
+   * @param env Environment whose variables are expanded.
+   * @param val_raw Text containing variable references.
+   * @return Text with environment references expanded.
+   */
+  std::string parse_env_val(boost::process::v1::native_environment &env, const std::string_view &val_raw);
+}  // namespace proc
+
+#ifdef _WIN32
+TEST(ProcessTest, ExpandsEnvironmentNamesWithoutChangingTheirCase) {
+  auto env = boost::this_process::environment();
+  const std::string key = "SUNSHINE_RANGE_SEARCH_REGRESSION";
+  const auto original = env.find(key);
+  const std::optional<std::string> saved = original == env.end() ? std::nullopt : std::optional {original->to_string()};
+  const auto restore = util::fail_guard([&env, &key, &saved]() {
+    if (saved.has_value()) {
+      env[key] = *saved;
+    } else {
+      env[key].clear();
+    }
+  });
+  env[key] = "case-preserved";
+
+  EXPECT_EQ(proc::parse_env_val(env, "before-$(sunshine_range_search_regression)-after"), "before-case-preserved-after");
+  EXPECT_EQ(proc::parse_env_val(env, "$(SUNSHINE_RANGE_SEARCH_REGRESSION)"), "case-preserved");
+}
+#endif
+
+TEST(ProcessTest, UrlCommandsDoNotResolveAnExecutableWorkingDirectory) {
+  boost::process::v1::environment env;
+  EXPECT_TRUE(proc::find_working_directory("https://example.com", env).empty());
+  EXPECT_TRUE(proc::find_working_directory("steam://run/123", env).empty());
+  EXPECT_TRUE(proc::find_working_directory("custom+scheme://host/path", env).empty());
+}
+
 TEST(ProcessTest, PrepareCommand) {
 #ifdef SUNSHINE_BUILD_FLATPAK
   EXPECT_EQ(proc::prepare_command("steam"), "flatpak-spawn --host steam");

tests/unit/test_string_hash.cpp

@@ -0,0 +1,42 @@
+/**
+ * @file tests/unit/test_string_hash.cpp
+ * @brief Regression coverage for heterogeneous owning-string containers.
+ */
+
+// test includes
+#include "../tests_common.h"
+
+// standard includes
+#include <string>
+#include <string_view>
+#include <unordered_map>
+
+// local includes
+#include <src/string_hash.h>
+
+TEST(TransparentStringHashTest, EquivalentKeyRepresentationsFindTheSameEntry) {
+  const std::string key(128, 'k');
+  const std::string padded = "prefix" + key + "suffix";
+  const auto view = std::string_view {padded}.substr(6, key.size());
+  std::unordered_map<std::string, int, util::transparent_string_hash, std::equal_to<>> entries {{key, 42}};
+
+  EXPECT_EQ(entries.find(key)->second, 42);
+  EXPECT_EQ(entries.find(key.c_str())->second, 42);
+  EXPECT_EQ(entries.find(view)->second, 42);
+  EXPECT_FALSE(entries.contains(std::string_view {padded}));
+  EXPECT_EQ(entries.size(), 1);
+}
+
+TEST(TransparentStringHashTest, EmptyAndEmbeddedNullKeysRetainTheirLengths) {
+  using namespace std::literals;
+  std::unordered_map<std::string, int, util::transparent_string_hash, std::equal_to<>> entries {
+    {"", 1},
+    {"key\0suffix"s, 2},
+    {"key", 3},
+  };
+
+  EXPECT_EQ(entries.find(""sv)->second, 1);
+  EXPECT_EQ(entries.find("key\0suffix"sv)->second, 2);
+  EXPECT_EQ(entries.find("key")->second, 3);
+  EXPECT_FALSE(entries.contains("key\0other"sv));
+}

tests/unit/test_sync.cpp

@@ -0,0 +1,92 @@
+/**
+ * @file tests/unit/test_sync.cpp
+ * @brief Regression coverage for synchronized-value lock lifetimes.
+ */
+
+// standard includes
+#include <array>
+#include <stdexcept>
+#include <system_error>
+#include <thread>
+
+// lib includes
+#include <gtest/gtest.h>
+
+// local includes
+#include <src/sync.h>
+
+namespace {
+  /**
+   * @brief BasicLockable mutex that detects an unreleased lock without requiring try_lock.
+   */
+  class basic_mutex {
+  public:
+    /**
+     * @brief Acquire the mutex, rejecting recursive locking.
+     *
+     * @throws std::system_error If the mutex is already locked.
+     */
+    void lock() {
+      if (held_) {
+        throw std::system_error {std::make_error_code(std::errc::resource_deadlock_would_occur)};
+      }
+      held_ = true;
+    }
+
+    /**
+     * @brief Release the mutex.
+     */
+    void unlock() noexcept {
+      held_ = false;
+    }
+
+  private:
+    bool held_ {false};  ///< Whether a guard currently owns this mutex.
+  };
+}  // namespace
+
+TEST(SyncLockTest, RejectsRecursiveLockingAndReleasesTheOriginalGuard) {
+  sync_util::sync_t<int, basic_mutex> value {0};
+  {
+    const auto guard = value.lock();
+    EXPECT_THROW(value.lock(), std::system_error);
+  }
+  EXPECT_NO_THROW(value.lock());
+}
+
+TEST(SyncLockTest, SupportsBasicLockableAndReleasesOnException) {
+  sync_util::sync_t<int, basic_mutex> value {0};
+  EXPECT_THROW(
+    [&value]() {
+      const auto guard = value.lock();
+      ++*value;
+      throw std::runtime_error {"unwind the guard"};
+    }(),
+    std::runtime_error
+  );
+
+  EXPECT_NO_THROW([&value]() {
+    const auto guard = value.lock();
+    EXPECT_EQ(*value, 1);
+  }());
+  EXPECT_NO_THROW([&value]() {
+    const auto guard = value.lock();
+    EXPECT_EQ(*value, 1);
+  }());
+}
+
+TEST(SyncLockTest, SerializesConcurrentUpdates) {
+  sync_util::sync_t<int> value {0};
+  {
+    std::array<std::jthread, 4> workers;
+    for (auto &worker : workers) {
+      worker = std::jthread {[&value]() {
+        for (int i = 0; i < 250; ++i) {
+          const auto guard = value.lock();
+          ++*value;
+        }
+      }};
+    }
+  }
+  EXPECT_EQ(*value, 1000);
+}

tests/unit/test_task_pool.cpp

@@ -0,0 +1,38 @@
+/**
+ * @file tests/unit/test_task_pool.cpp
+ * @brief Regression coverage for delayed task lookup over the complete queue.
+ */
+
+// lib includes
+#include <gtest/gtest.h>
+
+// local includes
+#include <src/task_pool.h>
+
+TEST(TaskPoolTest, FindsRequestedDelayedTaskAndRejectsMissingIdentifiers) {
+  using namespace std::chrono_literals;
+  task_pool_util::TaskPool pool;
+  EXPECT_FALSE(pool.pop(nullptr).has_value());
+
+  auto first = pool.pushDelayed([]() {
+    return 11;
+  },
+                                1h);
+  auto second = pool.pushDelayed([]() {
+    return 22;
+  },
+                                 2h);
+  EXPECT_FALSE(pool.pop(nullptr).has_value());
+
+  auto removed = pool.pop(first.task_id);
+  ASSERT_TRUE(removed.has_value());
+  ASSERT_NE(removed->second, nullptr);
+  removed->second->run();
+  EXPECT_EQ(first.future.get(), 11);
+
+  auto other = pool.pop(second.task_id);
+  ASSERT_TRUE(other.has_value());
+  ASSERT_NE(other->second, nullptr);
+  other->second->run();
+  EXPECT_EQ(second.future.get(), 22);
+}

tests/unit/test_utility.cpp

@@ -267,13 +267,26 @@ TEST(UtilityBufferTests, MoveConstruction) {
 
 TEST(UtilityBufferTests, CopyConstruction) {
   util::buffer_t buf1(3, 55);
+  buf1[1] = 66;
+  buf1[2] = 77;
   util::buffer_t<int> buf2(buf1);
   EXPECT_EQ(buf2.size(), 3U);
   EXPECT_EQ(buf2[0], 55);
+  EXPECT_EQ(buf2[1], 66);
+  EXPECT_EQ(buf2[2], 77);
   EXPECT_EQ(buf1.size(), 3U);
   EXPECT_EQ(buf1[0], 55);
 }
 
+TEST(UtilityBufferTests, CopiesAnEmptyLogicalRange) {
+  util::buffer_t buf(3, 42);
+  buf.fake_resize(0);
+  const util::buffer_t<int> copy(buf);
+  EXPECT_EQ(copy.size(), 0U);
+  EXPECT_EQ(copy.begin(), copy.end());
+  EXPECT_EQ(buf[0], 42);
+}
+
 TEST(UtilityBufferTests, SizeConstructionValueInitializesEveryElement) {
   const util::buffer_t<int> buf(4);
   EXPECT_EQ(buf.end() - buf.begin(), 4);