Allow returning empty path in Steam_Apps::GetAppInstallDir()

dll/dll/settings.h

@@ -401,7 +401,7 @@ class Settings {
 
     //App Install paths
     void setAppInstallPath(AppId_t appID, const std::string &path);
-    std::string getAppInstallPath(AppId_t appID);
+    bool getAppInstallPath(AppId_t appID, std::string &path);
 
     //mod stuff
     void addMod(PublishedFileId_t id, const std::string &title, const std::string &path);

dll/settings.cpp

@@ -328,9 +328,16 @@ void Settings::setAppInstallPath(AppId_t appID, const std::string &path)
     app_paths[appID] = path;
 }
 
-std::string Settings::getAppInstallPath(AppId_t appID)
+bool Settings::getAppInstallPath(AppId_t appID, std::string &path)
 {
-    return app_paths[appID];
+    auto app_path = app_paths.find(appID);
+    if (app_paths.end() != app_path)
+    {
+        path = app_path->second;
+        return true;
+    }
+
+    return false;
 }
 
 void Settings::setLeaderboard(const std::string &leaderboard, enum ELeaderboardSortMethod sort_method, enum ELeaderboardDisplayType display_type)

dll/settings_parser.cpp

@@ -767,15 +767,18 @@ static void parse_app_paths(class Settings *settings_client, Settings *settings_
 
     for (const auto &id : ids) {
         auto val_ptr = ini.GetValue("app::paths", id.pItem);
-        if (!val_ptr || !val_ptr[0]) continue;
+        // NOTE: empty path means we actively disable the path to the appid specified
+        if (!val_ptr) continue;
 
         AppId_t appid = (AppId_t)std::stoul(id.pItem);
         std::string rel_path(val_ptr);
-        std::string path = canonical_path(program_path + rel_path);
+        std::string path{};
+        if (rel_path.size())
+            path = canonical_path(program_path + rel_path);
 
         if (appid) {
-            if (path.size()) {
-                PRINT_DEBUG("Adding app path: %u|%s|", appid, path.c_str());
+            if (!rel_path.size() || path.size()) {
+                PRINT_DEBUG("Adding app path: %u|%s|%s", appid, rel_path.c_str(), path.c_str());
                 settings_client->setAppInstallPath(appid, path);
                 settings_server->setAppInstallPath(appid, path);
             } else {

dll/steam_apps.cpp

@@ -321,9 +321,9 @@ uint32 Steam_Apps::GetAppInstallDir( AppId_t appID, char *pchFolder, uint32 cchF
     PRINT_DEBUG("%u %p %u", appID, pchFolder, cchFolderBufferSize);
     std::lock_guard<std::recursive_mutex> lock(global_mutex);
     //TODO return real path instead of dll path
-    std::string installed_path = settings->getAppInstallPath(appID);
+    std::string installed_path;
 
-    if (installed_path.empty()) {
+    if (!settings->getAppInstallPath(appID, installed_path)) {
         std::string dll_path = get_full_program_path();
         std::string current_path = get_current_path();
         PRINT_DEBUG("  dll: '%s', current: '%s'", dll_path.c_str(), current_path.c_str());
@@ -335,6 +335,9 @@ uint32 Steam_Apps::GetAppInstallDir( AppId_t appID, char *pchFolder, uint32 cchF
             installed_path = dll_path;
         }
     }
+    else if (installed_path.empty()) {
+        return 0; // NOTE: empty path means we actively disable the path to the appid specified
+    }
 
     PRINT_DEBUG("  final path '%s'", installed_path.c_str());
     if (pchFolder && cchFolderBufferSize) {

post_build/steam_settings.EXAMPLE/configs.app.EXAMPLE.ini

@@ -24,7 +24,13 @@ unlock_all=0
 56789=This is another example DLC name
 
 [app::paths]
+# some rare games might need to be provided one or more paths to appids
+# for example the path to where a DLC is installed
+# this sets the paths returned by the Steam_Apps::GetAppInstallDir function
 556760=../DLCRoot0
 1234=./folder_where_steam_api_is
 3456=../folder_one_level_above_where_steam_api_is
 5678=../../folder_two_levels_above_where_steam_api_is
+# however some other games might expect this function to return empty paths to properly load DLCs
+# you can deliberately set the path to be empty to specify this behavior like lines below
+1337=