💥 Encapsulate and rework all socket logic

This is a pretty huge change that will be important for being able to
handle nested or mutually recursive `dispatch()` and `audioMaster()`
calls. This sadly all had to be done in a single commit, so here's a
summary:

- `src/common/sockets.h:Sockets` contains all sockets on both the plugin
  and the Wine host side, and is used to both listen on and connect to
  the sockets.
- Sockets and other temporary files respect `$XDG_RUNTIME_DIR` instead
  of being dumped in `/tmp`.
- All sockets now have a unique endpoint in
  `/run/user/<uid>/yabridge-<plugin_name>-<random_id>/`. This is
  important for when we want to have multiple socket connections for
  handling `dispatch()` and `audioMaster()`.
- Because of the above, we no longer clean up the socket endpoint files
  after the connection gets established during initialization. Instead
  we'll remove the socket base directory when shutting down.

src/plugin/utils.cpp

@@ -22,37 +22,27 @@
 #include <boost/process/search_path.hpp>
 #include <boost/process/system.hpp>
 #include <fstream>
-#include <random>
 #include <sstream>
 
 // Generated inside of the build directory
 #include <src/common/config/config.h>
 
 #include "../common/configuration.h"
+#include "../common/utils.h"
 
 namespace bp = boost::process;
 namespace fs = boost::filesystem;
 
-/**
- * Used for generating random identifiers.
- */
-constexpr char alphanumeric_characters[] =
-    "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
-
-std::string create_logger_prefix(const fs::path& socket_path) {
-    // Use the socket filename as the logger prefix, but strip the `yabridge-`
-    // part since that's redundant
-    std::string socket_name =
-        socket_path.filename().replace_extension().string();
+std::string create_logger_prefix(const fs::path& endpoint_base_dir) {
+    // Use the name of the base directory used for our sockets as the logger
+    // prefix, but strip the `yabridge-` part since that's redundant
+    std::string endpoint_name = endpoint_base_dir.filename().string();
 
     constexpr std::string_view socket_prefix("yabridge-");
-    assert(socket_name.starts_with(socket_prefix));
-    socket_name = socket_name.substr(socket_prefix.size());
+    assert(endpoint_name.starts_with(socket_prefix));
+    endpoint_name = endpoint_name.substr(socket_prefix.size());
 
-    std::ostringstream prefix;
-    prefix << "[" << socket_name << "] ";
-
-    return prefix.str();
+    return "[" + endpoint_name + "] ";
 }
 
 std::optional<fs::path> find_wineprefix() {
@@ -183,39 +173,7 @@ boost::filesystem::path generate_group_endpoint(
     }
     socket_name << ".sock";
 
-    return fs::temp_directory_path() / socket_name.str();
-}
-
-fs::path generate_plugin_endpoint() {
-    const auto plugin_name =
-        find_vst_plugin().filename().replace_extension("").string();
-
-    std::random_device random_device;
-    std::mt19937 rng(random_device());
-    fs::path candidate_endpoint;
-    do {
-        std::string random_id;
-        std::sample(
-            alphanumeric_characters,
-            alphanumeric_characters + strlen(alphanumeric_characters) - 1,
-            std::back_inserter(random_id), 8, rng);
-
-        // We'll get rid of the file descriptors immediately after accepting the
-        // sockets, so putting them inside of a subdirectory would only leave
-        // behind an empty directory
-        std::ostringstream socket_name;
-        socket_name << "yabridge-" << plugin_name << "-" << random_id
-                    << ".sock";
-
-        candidate_endpoint = fs::temp_directory_path() / socket_name.str();
-    } while (fs::exists(candidate_endpoint));
-
-    // TODO: Should probably try creating the endpoint right here and catch any
-    //       exceptions since this could technically result in a race condition
-    //       when two instances of yabridge decide to use the same endpoint name
-    //       at the same time
-
-    return candidate_endpoint;
+    return get_temporary_directory() / socket_name.str();
 }
 
 fs::path get_this_file_location() {
@@ -243,7 +201,7 @@ std::string get_wine_version() {
 
     bp::environment env = boost::this_process::environment();
     if (!env["WINELOADER"].empty()) {
-        wine_command = env.get("WINELOADER");
+        wine_command = env["WINELOADER"].to_string();
     }
 
     bp::ipstream output;
@@ -271,13 +229,13 @@ std::string get_wine_version() {
 
 std::string join_quoted_strings(std::vector<std::string>& strings) {
     bool is_first = true;
-    std::ostringstream joined_strigns{};
+    std::ostringstream joined_strings{};
     for (const auto& option : strings) {
-        joined_strigns << (is_first ? "'" : ", '") << option << "'";
+        joined_strings << (is_first ? "'" : ", '") << option << "'";
         is_first = false;
     }
 
-    return joined_strigns.str();
+    return joined_strings.str();
 }
 
 Configuration load_config_for(const fs::path& yabridge_path) {