Add code to find luprex root directory

luprex/cpp/drv/driver.cpp

@@ -23,6 +23,27 @@ static void dprint_callback(const char *oneline, size_t size) {
     fflush(stderr);
 }
 
+inline bool file_exists(const std::filesystem::path &name) {
+    std::ifstream f(name);
+    return f.good();
+}
+
+std::filesystem::path find_luprex_root(std::filesystem::path exepath) {
+    std::filesystem::path pp = exepath.parent_path();
+    if (file_exists(pp / "lua/control.lst")) {
+        return pp;
+    }
+    pp = pp.parent_path();
+    if (file_exists(pp / "lua/control.lst")) {
+        return pp;
+    }
+    pp = pp.parent_path();
+    if (file_exists(pp / "lua/control.lst")) {
+        return pp;
+    }
+    assert(false && "Could not find lua/control.lst");
+}
+
 class Driver {
    public:
     enum ChanState {
@@ -60,6 +81,7 @@ class Driver {
         bool marked_for_deletion() const { return state == CHAN_INACTIVE; }
     };
 
+    std::string luprexroot;
     EngineWrapper engw;
     std::vector<ChanInfo> chans_;
     std::map<int, SOCKET> listen_sockets_;
@@ -557,8 +579,11 @@ class Driver {
         argc -= 1;
         argv += 1;
 
+        // Find the root of the luprex tree.
+        luprexroot = find_luprex_root(get_exe_path());
+
         // Load the DLL and gain access to its functions.
-        call_init_engine_wrapper(&engw);
+        call_init_engine_wrapper(luprexroot, &engw);
         engw.replay_cb_sent_outgoing = replay_cb_sent_outgoing;
         engw.hook_dprint(dprint_callback);
 
@@ -605,7 +630,7 @@ class Driver {
 
         // Read the initial lua source code.
         drvutil::ostringstream srcpak;
-        std::string srcpakerr = drvutil::package_lua_source(".", &srcpak);
+        std::string srcpakerr = drvutil::package_lua_source(luprexroot, &srcpak);
         if_error_print_and_exit(srcpakerr);
 
         // Initialize the engine.