Added experimental support for folder flattening.

es-app/src/FileData.cpp

@@ -446,7 +446,8 @@ const bool FileData::isArcadeGame() const
 void FileData::addChild(FileData* file)
 {
     assert(mType == FOLDER);
-    assert(file->getParent() == nullptr);
+    if (!mSystem->getFlattenFolders())
+        assert(file->getParent() == nullptr);
 
     const std::string key = file->getKey();
     if (mChildrenByFilename.find(key) == mChildrenByFilename.cend()) {

es-app/src/GamelistFileParser.cpp

@@ -85,12 +85,14 @@ namespace GamelistFileParser
                     return nullptr;
                 }
 
-                // Create missing folder.
+                if (!system->getFlattenFolders()) {
-                FileData* folder = new FileData(
+                    // Create missing folder.
-                    FOLDER, Utils::FileSystem::getStem(treeNode->getPath()) + "/" + *path_it,
+                    FileData* folder {new FileData(
-                    system->getSystemEnvData(), system);
+                        FOLDER, Utils::FileSystem::getStem(treeNode->getPath()) + "/" + *path_it,
-                treeNode->addChild(folder);
+                        system->getSystemEnvData(), system)};
-                treeNode = folder;
+                    treeNode->addChild(folder);
+                    treeNode = folder;
+                }
             }
 
             ++path_it;

es-app/src/SystemData.cpp

@@ -185,17 +185,18 @@ SystemData::SystemData(const std::string& name,
                        const std::string& themeFolder,
                        bool CollectionSystem,
                        bool CustomCollectionSystem)
-    : mName(name)
+    : mName {name}
-    , mFullName(fullName)
+    , mFullName {fullName}
-    , mSortName(sortName)
+    , mSortName {sortName}
-    , mEnvData(envData)
+    , mEnvData {envData}
-    , mThemeFolder(themeFolder)
+    , mThemeFolder {themeFolder}
-    , mIsCollectionSystem(CollectionSystem)
+    , mIsCollectionSystem {CollectionSystem}
-    , mIsCustomCollectionSystem(CustomCollectionSystem)
+    , mIsCustomCollectionSystem {CustomCollectionSystem}
-    , mIsGroupedCustomCollectionSystem(false)
+    , mIsGroupedCustomCollectionSystem {false}
-    , mIsGameSystem(true)
+    , mIsGameSystem {true}
-    , mScrapeFlag(false)
+    , mScrapeFlag {false}
-    , mPlaceholder(nullptr)
+    , mFlattenFolders {false}
+    , mPlaceholder {nullptr}
 {
     mFilterIndex = new FileFilterIndex();
 
@@ -271,6 +272,13 @@ bool SystemData::populateFolder(FileData* folder)
     if (dirContent.size() == 0)
         return false;
 
+    if (std::find(dirContent.cbegin(), dirContent.cend(), mEnvData->mStartPath + "/flatten.txt") !=
+        dirContent.cend()) {
+        LOG(LogInfo) << "A flatten.txt file is present for the \"" << mName
+                     << "\" system, folder flattening will be applied";
+        mFlattenFolders = true;
+    }
+
     for (Utils::FileSystem::StringList::const_iterator it = dirContent.cbegin();
          it != dirContent.cend(); ++it) {
         filePath = *it;
@@ -344,11 +352,17 @@ bool SystemData::populateFolder(FileData* folder)
             FileData* newFolder = new FileData(FOLDER, filePath, mEnvData, this);
             populateFolder(newFolder);
 
-            // Ignore folders that do not contain games.
+            if (mFlattenFolders) {
-            if (newFolder->getChildrenByFilename().size() == 0)
+                for (auto& entry : newFolder->getChildrenByFilename())
-                delete newFolder;
+                    folder->addChild(entry.second);
-            else
+            }
-                folder->addChild(newFolder);
+            else {
+                // Ignore folders that do not contain games.
+                if (newFolder->getChildrenByFilename().size() == 0)
+                    delete newFolder;
+                else
+                    folder->addChild(newFolder);
+            }
         }
     }
     return true;

es-app/src/SystemData.h

@@ -97,6 +97,7 @@ public:
     std::string getThemePath() const;
 
     std::pair<unsigned int, unsigned int> getDisplayedGameCount() const;
+    const bool getFlattenFolders() const { return mFlattenFolders; }
     const bool getScrapeFlag() const { return mScrapeFlag; }
     void setScrapeFlag(bool scrapeflag) { mScrapeFlag = scrapeflag; }
 
@@ -156,6 +157,7 @@ private:
     bool mIsGroupedCustomCollectionSystem;
     bool mIsGameSystem;
     bool mScrapeFlag; // Only used by scraper GUI to remember which systems to scrape.
+    bool mFlattenFolders;
 
     bool populateFolder(FileData* folder);
     void indexAllGameFilters(const FileData* folder);