Simplify VFS index iteration

apps/openmw/mwlua/vfsbindings.cpp

@@ -160,25 +160,6 @@ namespace MWLua
 
         auto vfs = MWBase::Environment::get().getResourceSystem()->getVFS();
 
-        sol::usertype<VFS::Manager::StatefulIterator> vfsIterator
-            = context.mLua->sol().new_usertype<VFS::Manager::StatefulIterator>("VFSIterator");
-        vfsIterator[sol::meta_function::to_string] = [](const VFS::Manager::StatefulIterator& vfsIterator) {
-            return "VFSIterator{'" + vfsIterator.getPath() + "'}";
-        };
-        vfsIterator["path"] = sol::readonly_property(
-            [](const VFS::Manager::StatefulIterator& vfsIterator) { return vfsIterator.getPath(); });
-
-        auto createIter = [](VFS::Manager::StatefulIterator& vfsIterator) {
-            return sol::as_function([vfsIterator, i = 1]() mutable {
-                if (auto v = vfsIterator.next())
-                    return std::tuple<sol::optional<int>, sol::optional<std::string_view>>(i++, *v);
-                else
-                    return std::tuple<sol::optional<int>, sol::optional<std::string_view>>(sol::nullopt, sol::nullopt);
-            });
-        };
-        vfsIterator["__pairs"] = createIter;
-        vfsIterator["__ipairs"] = createIter;
-
         sol::usertype<FileHandle> handle = context.mLua->sol().new_usertype<FileHandle>("FileHandle");
         handle["fileName"] = sol::readonly_property([](const FileHandle& self) { return self.mFileName; });
         handle[sol::meta_function::to_string] = [](const FileHandle& self) {
@@ -346,8 +327,19 @@ namespace MWLua
             [](const sol::object&) -> sol::object { return sol::nil; });
 
         api["fileExists"] = [vfs](std::string_view fileName) -> bool { return vfs->exists(fileName); };
-        api["getIterator"]
+        api["pathsWithPrefix"] = [vfs](std::string_view prefix) {
-            = [vfs](std::string_view path) -> VFS::Manager::StatefulIterator { return vfs->getStatefulIterator(path); };
+            auto iterator = vfs->getRecursiveDirectoryIterator(prefix);
+            return sol::as_function([iterator, current = iterator.begin()]() mutable -> sol::optional<std::string> {
+                if (current != iterator.end())
+                {
+                    const std::string& result = *current;
+                    ++current;
+                    return result;
+                }
+
+                return sol::nullopt;
+            });
+        };
 
         return LuaUtil::makeReadOnly(api);
     }

components/vfs/manager.cpp

@@ -89,17 +89,4 @@ namespace VFS
         ++normalized.back();
         return { it, mIndex.lower_bound(normalized) };
     }
-
-    Manager::StatefulIterator Manager::getStatefulIterator(std::string_view path) const
-    {
-        if (path.empty())
-            return { mIndex.begin(), mIndex.end(), std::string() };
-        std::string normalized = Path::normalizeFilename(path);
-        const auto it = mIndex.lower_bound(normalized);
-        if (it == mIndex.end() || !startsWith(it->first, normalized))
-            return { it, it, normalized };
-        std::string upperBound = normalized;
-        ++upperBound.back();
-        return { it, mIndex.lower_bound(upperBound), normalized };
-    }
 }

components/vfs/manager.hpp

@@ -6,7 +6,6 @@
 #include <filesystem>
 #include <map>
 #include <memory>
-#include <optional>
 #include <string>
 #include <vector>
 
@@ -49,18 +48,11 @@ namespace VFS
             const std::string& operator*() const { return mIt->first; }
             const std::string* operator->() const { return &mIt->first; }
             bool operator!=(const RecursiveDirectoryIterator& other) { return mIt != other.mIt; }
-            bool operator==(const RecursiveDirectoryIterator& other) const { return mIt == other.mIt; }
             RecursiveDirectoryIterator& operator++()
             {
                 ++mIt;
                 return *this;
             }
-            RecursiveDirectoryIterator operator++(int)
-            {
-                RecursiveDirectoryIterator old = *this;
-                mIt++;
-                return old;
-            }
 
         private:
             std::map<std::string, File*>::const_iterator mIt;
@@ -69,31 +61,6 @@ namespace VFS
         using RecursiveDirectoryRange = IteratorPair<RecursiveDirectoryIterator>;
 
     public:
-        class StatefulIterator : RecursiveDirectoryRange
-        {
-        public:
-            StatefulIterator(RecursiveDirectoryIterator first, RecursiveDirectoryIterator last, const std::string& path)
-                : RecursiveDirectoryRange(first, last)
-                , mCurrent(first)
-                , mPath(path)
-            {
-            }
-
-            const std::string& getPath() const { return mPath; }
-
-            std::optional<std::string_view> next()
-            {
-                if (mCurrent == end())
-                    return std::nullopt;
-
-                return *mCurrent++;
-            }
-
-        private:
-            RecursiveDirectoryIterator mCurrent;
-            std::string mPath;
-        };
-
         // Empty the file index and unregister archives.
         void reset();
 
@@ -126,13 +93,6 @@ namespace VFS
         /// @note May be called from any thread once the index has been built.
         RecursiveDirectoryRange getRecursiveDirectoryIterator(std::string_view path) const;
 
-        /// Recursively iterate over the elements of the given path
-        /// In practice it return all files of the VFS starting with the given path
-        /// Stores iterator to current element.
-        /// @note the path is normalized
-        /// @note May be called from any thread once the index has been built.
-        StatefulIterator getStatefulIterator(std::string_view path) const;
-
         /// Retrieve the absolute path to the file
         /// @note Throws an exception if the file can not be found.
         /// @note May be called from any thread once the index has been built.

files/lua_api/openmw/vfs.lua

@@ -6,10 +6,6 @@
 
 
 
----
--- @type VFSIterator
--- @field #string path VFS prefix path
-
 ---
 -- @type FileHandle
 -- @field #string fileName VFS path to related file
@@ -135,14 +131,18 @@
 -- end
 
 ---
--- Get iterator to fetch file names with given path prefix from VFS
+-- Get iterator function to fetch file names with given path prefix from VFS
--- @function [parent=#vfs] getIterator
+-- @function [parent=#vfs] pathsWithPrefix
 -- @param #string path Path prefix
--- @return #VFSIterator Opened iterator
+-- @return #function Function to get next file name
--- @usage local dir = vfs.getIterator("Music\\Explore");
+-- @usage -- get all files with given prefix from VFS index
--- for _, fileName in pairs(dir) do
+-- for fileName in vfs.pathsWithPrefix("Music\\Explore") do
 --     print(fileName);
 -- end
+-- @usage -- get some first files
+-- local getNextFile = vfs.pathsWithPrefix("Music\\Explore");
+-- local firstFile = getNextFile();
+-- local secondFile = getNextFile();
 
 ---
 -- Detect a file handle type