Filesystem.cpp

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#include "filesystem/physfs/Filesystem.h"
 
#include <algorithm>
#include <iostream>
#include <memory>
#include <mutex>
#include <sstream>
#include <string>
 
#include "filesystem/physfs/File.h"
#include "common/b64.h"
#include "common/utf8.h"
#include "common/Exception.h"
#include "common/Diagnostic.h"
#include "cmdline/cmdline.h"
 
// PhysFS
#include "physfs/physfs.h"
 
#ifdef EVENGINE_WINDOWS
#include <direct.h>
#include <windows.h>
#else
#include <sys/param.h>
#include <unistd.h>
#endif
 
#ifdef EVENGINE_IOS
#include "ios/ios.h"
#endif
 
#ifdef EVENGINE_WEBGPU
#include "webgpu/webplatform.h"
#endif
 
#include <filesystem>
#include <string>
 
#ifdef EVENGINE_ANDROID
#include <SDL2/SDL.h>
 
#include "android/android.h"
#endif
 
using namespace std;
 
namespace {
size_t getDriveDelim(const std::string &input) {
    for (size_t i = 0; i < input.size(); ++i)
        if (input[i] == '/' || input[i] == '\\') return i;
    // Something's horribly wrong
    return 0;
}
 
std::string getDriveRoot(const std::string &input) { return input.substr(0, getDriveDelim(input) + 1); }
 
std::string skipDriveRoot(const std::string &input) { return input.substr(getDriveDelim(input) + 1); }
 
std::string normalize(const std::string &input) {
    std::stringstream out;
 
    bool seenSep = false, isSep = false;
    for (size_t i = 0; i < input.size(); ++i) {
        isSep = (input[i] == EVENGINE_PATH_SEPARATOR[0]);
        if (!isSep || !seenSep) out << input[i];
        seenSep = isSep;
    }
 
    return out.str();
}
 
}  // namespace
 
namespace eve {
namespace filesystem {
namespace physfs {
 
Filesystem::Filesystem() : fused(false), fusedSet(false) {
    requirePath  = {"?.lua", "?/init.lua"};
    cRequirePath = {"??"};
    if (auto* c = getModInst(eve::cmd,Cmdline)) {
        // unit_test / embedders never call Cmdline::runArgs: argv stays empty.
        const std::string a0 = c->getArgv(0);
        if (a0.empty()) init(NULL);
        else init(a0.c_str());
    } else {
        init(NULL);
    }
}
 
Filesystem::~Filesystem() {
    unwatchAll();
 
    if (memoryArchive_) {
        free(memoryArchive_);
        memoryArchive_ = nullptr;
    }
 
#ifdef EVENGINE_ANDROID
    android::deinitializeVirtualArchive();
#endif
 
    if (PHYSFS_isInit()) PHYSFS_deinit();
}
 
void Filesystem::init(const char* arg0) {
    if (!PHYSFS_init(arg0))
        throw Exception("Failed to initialize filesystem: %s", PHYSFS_getErrorByCode(PHYSFS_getLastErrorCode()));
 
    // Enable symlinks by default.
    setSymlinksEnabled(true);
}
 
void Filesystem::setFused(bool value) {
    if (fusedSet) return;
    this->fused = value;
    fusedSet    = true;
}
 
bool Filesystem::isFused() const {
    if (!fusedSet) return false;
    return fused;
}
 
bool Filesystem::setIdentity(std::string ident, bool appendToPath) {
    if (!PHYSFS_isInit()) return false;
 
    std::string old_save_path = save_path_full;
 
    // Store the save directory.
    save_identity = std::string(ident);
 
    // Generate the relative path to the game save folder.
    save_path_relative = std::string(EVENGINE_APPDATA_PREFIX EVENGINE_APPDATA_FOLDER EVENGINE_PATH_SEPARATOR) + save_identity;
 
    // Generate the full path to the game save folder.
    save_path_full = std::string(getAppdataDirectory()) + std::string(EVENGINE_PATH_SEPARATOR);
    if (fused)
        save_path_full += std::string(EVENGINE_APPDATA_PREFIX) + save_identity;
    else
        save_path_full += save_path_relative;
 
    save_path_full = normalize(save_path_full);
 
#ifdef EVENGINE_ANDROID
    if (save_identity == "") save_identity = "unnamed";
 
    std::string storage_path;
    if (isAndroidSaveExternal())
        storage_path = SDL_AndroidGetExternalStoragePath();
    else
        storage_path = SDL_AndroidGetInternalStoragePath();
 
    std::string save_directory = storage_path + "/save";
 
    save_path_full = storage_path + std::string("/save/") + save_identity;
 
    if (!android::directoryExists(save_path_full.c_str()) && !android::mkdir(save_path_full.c_str()))
        SDL_Log("Error: Could not create save directory %s!", save_path_full.c_str());
#endif
 
    // We now have something like:
    // save_identity: game
    // save_path_relative: ./LOVE/game
    // save_path_full: C:\Documents and Settings\user\Application Data/LOVE/game
 
    // We don't want old read-only save paths to accumulate when we set a new
    // identity.
    if (!old_save_path.empty()) PHYSFS_unmount(old_save_path.c_str());
 
    // Try to add the save directory to the search path.
    // (No error on fail, it means that the path doesn't exist).
    PHYSFS_mount(save_path_full.c_str(), nullptr, appendToPath);
 
    // HACK: This forces setupWriteDirectory to be called the next time a file
    // is opened for writing - otherwise it won't be called at all if it was
    // already called at least once before.
    PHYSFS_setWriteDir(nullptr);
 
    return true;
}
 
std::string Filesystem::getIdentity() const { return save_identity.c_str(); }
 
bool Filesystem::setSource(std::string source) {
    if (!PHYSFS_isInit()) return false;
 
    // Check whether directory is already set.
    if (!game_source.empty()) return false;
 
    std::string new_search_path = source;
 
#ifdef EVENGINE_ANDROID
    if (!android::createStorageDirectories()) SDL_Log("Error creating storage directories!");
 
    new_search_path = "";
 
    PHYSFS_Io *gameLoveIO;
    bool       hasFusedGame = android::checkFusedGame((void **)&gameLoveIO);
 
    if (hasFusedGame) {
        if (gameLoveIO) {
            // Actually we should just be able to mount gameLoveIO, but that's experimental.
            gameLoveIO->destroy(gameLoveIO);
            goto oldschool;
        } else {
            if (!android::initializeVirtualArchive()) {
                SDL_Log("Unable to mount AAsset: %s", PHYSFS_getErrorByCode(PHYSFS_getLastErrorCode()));
                return false;
            }
        }
    } else {
    oldschool:
        new_search_path = android::getSelectedGameFile();
 
        // try mounting first, if that fails, load to memory and mount
        if (!PHYSFS_mount(new_search_path.c_str(), nullptr, 1)) {
            // PHYSFS cannot yet mount a zip file inside an .apk
            SDL_Log("Mounting %s did not work. Loading to memory.", new_search_path.c_str());
            char * game_archive_ptr  = NULL;
            size_t game_archive_size = 0;
            if (!android::loadGameArchiveToMemory(new_search_path.c_str(), &game_archive_ptr,
                                                        &game_archive_size)) {
                SDL_Log("Failure memory loading archive %s", new_search_path.c_str());
                return false;
            }
            if (!PHYSFS_mountMemory(game_archive_ptr, game_archive_size, android::freeGameArchiveMemory,
                                    "archive.zip", "/", 0)) {
                SDL_Log("Failure mounting in-memory archive.");
                android::freeGameArchiveMemory(game_archive_ptr);
                return false;
            }
        }
    }
#else
    // Add the directory.
    if (!PHYSFS_mount(new_search_path.c_str(), nullptr, 1)) return false;
#endif
 
    // Save the game source.
    game_source = new_search_path;
 
    return true;
}
 
std::string Filesystem::getSource() const { return game_source.c_str(); }
 
bool Filesystem::setSourceFromMemory(const void* data, size_t size) {
    if (!PHYSFS_isInit() || !data || size == 0) return false;
    // Only one source per process.
    if (!game_source.empty()) return false;
 
    // PhysFS keeps a pointer to the buffer for the lifetime of the mount, so we
    // must own a copy that outlives it. Freed in the destructor.
    void* owned = malloc(size);
    if (!owned) return false;
    memcpy(owned, data, size);
 
    // Mount at "/" so dofile("config.nut") / "main.nut" resolve via PhysFS.
    if (!PHYSFS_mountMemory(owned, size, nullptr, "game.eve", "/", 1)) {
        const auto err = PHYSFS_getErrorByCode(PHYSFS_getLastErrorCode());
        std::cerr << "PhysFS mountMemory failed: " << (err ? err : "unknown error") << std::endl;
        free(owned);
        return false;
    }
 
    memoryArchive_ = owned;
    game_source    = "game.eve";
    return true;
}
 
bool Filesystem::setupWriteDirectory() {
    if (!PHYSFS_isInit()) return false;
 
    // These must have one be set.
    if (save_identity.empty() || save_path_full.empty() || save_path_relative.empty()) return false;
 
    // We need to make sure the write directory is created. To do that, we also
    // need to make sure all its parent directories are also created.
    std::string temp_writedir  = getDriveRoot(save_path_full);
    std::string temp_createdir = skipDriveRoot(save_path_full);
 
    // On some sandboxed platforms, physfs will break when its write directory
    // is the root of the drive and it tries to create a folder (even if the
    // folder's path is in a writable location.) If the user's home folder is
    // in the save path, we'll try starting from there instead.
    if (save_path_full.find(getUserDirectory()) == 0) {
        temp_writedir  = getUserDirectory();
        temp_createdir = save_path_full.substr(getUserDirectory().length());
 
        // Strip leading '/' characters from the path we want to create.
        size_t startpos = temp_createdir.find_first_not_of('/');
        if (startpos != std::string::npos) temp_createdir = temp_createdir.substr(startpos);
    }
 
    // Set either '/' or the user's home as a writable directory.
    // (We must create the save folder before mounting it).
    if (!PHYSFS_setWriteDir(temp_writedir.c_str())) return false;
 
    // Create the save folder. (We're now "at" either '/' or the user's home).
    if (!createDirectory(temp_createdir.c_str())) {
        // Clear the write directory in case of error.
        PHYSFS_setWriteDir(nullptr);
        return false;
    }
 
    // Set the final write directory.
    if (!PHYSFS_setWriteDir(save_path_full.c_str())) return false;
 
    // Add the directory. (Will not be readded if already present).
    if (!PHYSFS_mount(save_path_full.c_str(), nullptr, 0)) {
        PHYSFS_setWriteDir(nullptr);  // Clear the write directory in case of error.
        return false;
    }
 
    return true;
}
 
bool Filesystem::mount(std::string archive, std::string mountpoint, bool appendToPath) {
    if (!PHYSFS_isInit() || archive.empty()) return false;
 
    std::string realPath;
    std::string sourceBase = getSourceBaseDirectory();
 
    // Check whether the given archive path is in the list of allowed full paths.
    auto it = std::find(allowedMountPaths.begin(), allowedMountPaths.end(), archive);
 
    if (it != allowedMountPaths.end())
        realPath = *it;
    else if (isFused() && sourceBase.compare(archive) == 0) {
        // Special case: if the game is fused and the archive is the source's
        // base directory, mount it even though it's outside of the save dir.
        realPath = sourceBase;
    } else {
        // Not allowed for safety reasons.
        if (archive.size() == 0 || archive.find("..") != string::npos || archive == "/") return false;
 
        const char* realDir = PHYSFS_getRealDir(archive.c_str());
        if (!realDir) return false;
 
        realPath = realDir;
 
        // Always disallow mounting of files inside the game source, since it
        // won't work anyway if the game source is a zipped .love file.
        if (realPath.find(game_source) == 0) return false;
 
        realPath += EVENGINE_PATH_SEPARATOR;
        realPath += archive;
    }
 
    if (realPath.length() == 0) return false;
 
    return PHYSFS_mount(realPath.c_str(), mountpoint.c_str(), appendToPath) != 0;
}
 
bool Filesystem::mount(Data *data, std::string archivename, std::string mountpoint, bool appendToPath) {
    if (!PHYSFS_isInit()) return false;
 
    if (PHYSFS_mountMemory(data->getData(), data->getSize(), nullptr, archivename.c_str(), mountpoint.c_str(), appendToPath) != 0) {
        mountedData[archivename] = data;
        return true;
    }
 
    return false;
}
 
bool Filesystem::mountRealDirectory(std::string realDir, std::string mountpoint, bool appendToPath) {
    if (!PHYSFS_isInit() || realDir.empty()) return false;
    if (!isRealDirectory(realDir)) return false;
    if (mountpoint.empty()) mountpoint = "/";
 
    // Track the dir so unmountRealDirectory() / the destructor can clean it up,
    // even though PhysFS itself needs the OS path string to unmount.
    std::lock_guard<std::mutex> lock(mountMu_);
    if (std::find(mountedRealDirs_.begin(), mountedRealDirs_.end(), realDir) == mountedRealDirs_.end()) {
        if (!PHYSFS_mount(realDir.c_str(), mountpoint.c_str(), appendToPath ? 1 : 0)) return false;
        mountedRealDirs_.push_back(realDir);
    }
    return true;
}
 
bool Filesystem::unmountRealDirectory(std::string realDir) {
    std::lock_guard<std::mutex> lock(mountMu_);
    auto it = std::find(mountedRealDirs_.begin(), mountedRealDirs_.end(), realDir);
    if (it == mountedRealDirs_.end()) return false;
    const bool ok = PHYSFS_unmount(realDir.c_str()) != 0;
    mountedRealDirs_.erase(it);
    return ok;
}
 
bool Filesystem::unmount(std::string archive) {
    if (!PHYSFS_isInit() || archive.empty()) return false;
 
    auto datait = mountedData.find(archive);
 
    if (datait != mountedData.end() && PHYSFS_unmount(archive.c_str()) != 0) {
        mountedData.erase(datait);
        return true;
    }
 
    std::string realPath;
    std::string sourceBase = getSourceBaseDirectory();
 
    // Check whether the given archive path is in the list of allowed full paths.
    auto it = std::find(allowedMountPaths.begin(), allowedMountPaths.end(), archive);
 
    if (it != allowedMountPaths.end())
        realPath = *it;
    else if (isFused() && sourceBase.compare(archive) == 0) {
        // Special case: if the game is fused and the archive is the source's
        // base directory, unmount it even though it's outside of the save dir.
        realPath = sourceBase;
    } else {
        // Not allowed for safety reasons.
        if (archive.size() == 0 || archive.find("..") != string::npos || archive == "/") return false;
 
        const char* realDir = PHYSFS_getRealDir(archive.c_str());
        if (!realDir) return false;
 
        realPath = realDir;
        realPath += EVENGINE_PATH_SEPARATOR;
        realPath += archive;
    }
 
    const char* mountPoint = PHYSFS_getMountPoint(realPath.c_str());
    if (!mountPoint) return false;
 
    return PHYSFS_unmount(realPath.c_str()) != 0;
}
 
bool Filesystem::unmount(Data *data) {
    for (const auto &datapair : mountedData) {
        if (datapair.second == data) {
            std::string archive = datapair.first;
            return unmount(archive.c_str());
        }
    }
 
    return false;
}
 
filesystem::File *Filesystem::newFile(std::string filename) const { return new File(filename); }
 
std::string Filesystem::getWorkingDirectory() {
    if (cwd.empty()) {
#ifdef EVENGINE_WINDOWS
 
        WCHAR w_cwd[EVENGINE_MAX_PATH];
        _wgetcwd(w_cwd, EVENGINE_MAX_PATH);
        cwd = to_utf8(w_cwd);
        replace_char(cwd, '\\', '/');
#else
        char *cwd_char = new char[EVENGINE_MAX_PATH];
 
        if (getcwd(cwd_char, EVENGINE_MAX_PATH))
            cwd = cwd_char;  // if getcwd fails, cwd_char (and thus cwd) will still be empty
 
        delete[] cwd_char;
#endif
    }
 
    return cwd.c_str();
}
 
std::string Filesystem::getUserDirectory() {
#ifdef EVENGINE_IOS
    // PHYSFS_getUserDir doesn't give exactly the path we want on iOS.
    static std::string userDir = normalize(ios::getHomeDirectory());
#elif defined(EVENGINE_WEBGPU)
    static std::string userDir = normalize(eve::webgpu_platform::getHomeDirectory());
#else
    // PhysFS deprecated PHYSFS_getUserDir() in 2.1 without a non-deprecated
    // home-directory replacement (PHYSFS_getPrefDir() is app-specific), so the
    // public API is kept for the home-directory semantics.
#if defined(__GNUC__)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
#endif
    const char* dir = PHYSFS_getUserDir();
#if defined(__GNUC__)
#pragma GCC diagnostic pop
#endif
    static std::string userDir;
    if (dir) userDir = normalize(dir);
#endif
    return userDir;
}
 
std::string Filesystem::getAppdataDirectory() {
    if (appdata.empty()) {
#ifdef EVENGINE_WINDOWS_UWP
        appdata = getUserDirectory();
#elif defined(EVENGINE_WEBGPU)
        appdata = normalize(eve::webgpu_platform::getAppdataDirectory());
#elif defined(EVENGINE_WINDOWS)
        wchar_t *w_appdata = _wgetenv(L"APPDATA");
        appdata            = to_utf8(w_appdata);
        replace_char(appdata, '\\', '/');
#elif defined(EVENGINE_MACOSX)
        std::string udir = getUserDirectory();
        udir.append("/Library/Application Support");
        appdata = normalize(udir);
#elif defined(EVENGINE_IOS)
        appdata = normalize(ios::getAppdataDirectory());
#elif defined(EVENGINE_LINUX)
        char *xdgdatahome = getenv("XDG_DATA_HOME");
        if (!xdgdatahome)
            appdata = normalize(std::string(getUserDirectory()) + "/.local/share/");
        else
            appdata = xdgdatahome;
#else
        appdata = getUserDirectory();
#endif
    }
    return appdata;
}
 
std::string Filesystem::getSaveDirectory() { return save_path_full.c_str(); }
 
std::string Filesystem::getSourceBaseDirectory() const {
    size_t source_len = game_source.length();
 
    if (source_len == 0) return "";
 
        // FIXME: This doesn't take into account parent and current directory
        // symbols (i.e. '..' and '.')
#ifdef EVENGINE_WINDOWS
    // In windows, delimiters can be either '/' or '\'.
    size_t base_end_pos = game_source.find_last_of("/\\", source_len - 2);
#else
    size_t base_end_pos = game_source.find_last_of('/', source_len - 2);
#endif
 
    if (base_end_pos == std::string::npos) return "";
 
    // If the source is in the unix root (aka '/'), we want to keep the '/'.
    if (base_end_pos == 0) base_end_pos = 1;
 
    return game_source.substr(0, base_end_pos);
}
 
std::string Filesystem::getRealDirectory(std::string filename) const {
    if (!PHYSFS_isInit()) throw Exception("PhysFS is not initialized.");
 
    const char* dir = PHYSFS_getRealDir(filename.c_str());
 
    if (dir == nullptr) throw Exception("File does not exist on disk.");
 
    return std::string(dir);
}
 
bool Filesystem::getInfo(std::string filepath, Info &info) const {
    if (!PHYSFS_isInit()) return false;
 
    PHYSFS_Stat stat = {};
    if (!PHYSFS_stat(filepath.c_str(), &stat)) return false;
 
    info.size    = (int64_t)stat.filesize;
    info.modtime = (int64_t)stat.modtime;
 
    if (stat.filetype == PHYSFS_FILETYPE_REGULAR)
        info.type = "file";
    else if (stat.filetype == PHYSFS_FILETYPE_DIRECTORY)
        info.type = "directory";
    else if (stat.filetype == PHYSFS_FILETYPE_SYMLINK)
        info.type = "symlink";
    else
        info.type = "other";
 
    return true;
}
 
bool Filesystem::createDirectory(std::string dir) {
    if (!PHYSFS_isInit()) return false;
 
    if (PHYSFS_getWriteDir() == 0 && !setupWriteDirectory()) return false;
 
    if (!PHYSFS_mkdir(dir.c_str())) return false;
 
    return true;
}
 
bool Filesystem::remove(std::string file) {
    if (!PHYSFS_isInit()) return false;
 
    if (PHYSFS_getWriteDir() == 0 && !setupWriteDirectory()) return false;
 
    if (!PHYSFS_delete(file.c_str())) return false;
 
    return true;
}
 
FileData *Filesystem::read(std::string filename, int64_t size) const {
    physfs::File file(filename);
 
    file.open("rb");
 
    // close() is called in the File destructor.
    return file.read(size);
}
 
void Filesystem::write(std::string filename, const void *data, int64_t size) const {
    physfs::File file(filename);
 
    file.open("wb");
 
    // close() is called in the File destructor.
    if (!file.write(data, size)) throw eve::Exception("Data could not be written.");
}
 
void Filesystem::append(std::string filename, const void *data, int64_t size) const {
    physfs::File file(filename);
 
    file.open("ab");
 
    // close() is called in the File destructor.
    if (!file.write(data, size)) throw eve::Exception("Data could not be written.");
}
 
std::vector<std::string> Filesystem::getDirectoryItems(std::string dir) {
    std::vector<std::string> items;
    if (!PHYSFS_isInit()) return items;
 
    char **rc = PHYSFS_enumerateFiles(dir.c_str());
 
    if (rc == nullptr) return items;
 
    for (char **i = rc; *i != 0; i++) items.push_back(*i);
 
    PHYSFS_freeList(rc);
    return items;
}
 
void Filesystem::setSymlinksEnabled(bool enable) {
    if (!PHYSFS_isInit()) return;
 
    PHYSFS_permitSymbolicLinks(enable ? 1 : 0);
}
 
bool Filesystem::areSymlinksEnabled() const {
    if (!PHYSFS_isInit()) return false;
 
    return PHYSFS_symbolicLinksPermitted() != 0;
}
 
std::vector<std::string> &Filesystem::getRequirePath() { return requirePath; }
 
std::vector<std::string> &Filesystem::getCRequirePath() { return cRequirePath; }
 
void Filesystem::allowMountingForPath(const std::string &path) {
    if (std::find(allowedMountPaths.begin(), allowedMountPaths.end(), path) == allowedMountPaths.end())
        allowedMountPaths.push_back(path);
}
 
namespace {
 
bool looksAbsolute(const std::string &path) {
    if (path.empty()) return false;
    if (path[0] == '/' || path[0] == '\\') return true;
#ifdef EVENGINE_WINDOWS
    if (path.size() >= 2 && path[1] == ':') return true;
#endif
    return false;
}
 
std::string joinPath(const std::string &a, const std::string &b) {
    if (a.empty()) return b;
    if (b.empty()) return a;
    char last = a.back();
    if (last == '/' || last == '\\') return a + b;
    return a + "/" + b;
}
 
std::string parentDir(const std::string &path) {
    auto pos = path.find_last_of("/\\");
    if (pos == std::string::npos) return ".";
    if (pos == 0) return "/";
    return path.substr(0, pos);
}
 
std::string baseName(const std::string &path) {
    auto pos = path.find_last_of("/\\");
    if (pos == std::string::npos) return path;
    return path.substr(pos + 1);
}
 
bool hasParentSegment(const std::string &path) {
    if (path == "..") return true;
    if (path.size() >= 3 && (path.compare(0, 3, "../") == 0 || path.compare(0, 3, "..\\") == 0))
        return true;
    return path.find("/..") != std::string::npos || path.find("\\..") != std::string::npos;
}
 
std::filesystem::path pathFromUtf8(const std::string &text) {
    const auto *data = reinterpret_cast<const char8_t *>(text.data());
    return std::filesystem::path(std::u8string_view(data, text.size()));
}
 
std::string pathToUtf8(const std::filesystem::path &p) {
    auto u8 = p.u8string();
    return std::string(reinterpret_cast<const char *>(u8.data()), u8.size());
}
 
}  // namespace
 
FileWatch &Filesystem::watchers() {
    if (!fileWatch_) fileWatch_ = std::make_unique<FileWatch>();
    return *fileWatch_;
}
 
bool Filesystem::resolveWatchTarget(const std::string &path, std::string &realDir,
                                    std::string &filterName, std::string &reportPath) {
    reportPath = path;
    filterName.clear();
    realDir.clear();
    if (path.empty()) return false;
 
    // "." / "" are not reliable PhysFS paths — watch the real working directory.
    if (path == "." || path == "./") {
        reportPath = ".";
        realDir = getWorkingDirectory();
        filterName.clear();
        return isRealDirectory(realDir);
    }
 
    if (looksAbsolute(path)) {
        if (isRealDirectory(path)) {
            realDir = path;
            return true;
        }
        realDir = parentDir(path);
        filterName = baseName(path);
        return isRealDirectory(realDir);
    }
 
    // PhysFS rejects `..`. Resolve parent-relative paths against the real cwd
    // so `fs.watch("..")` / `hot.watchTree("..")` can see a parent workflow.
    if (hasParentSegment(path)) {
        std::error_code ec;
        auto candidate = std::filesystem::weakly_canonical(
            pathFromUtf8(getWorkingDirectory()) / pathFromUtf8(path), ec);
        if (!ec) {
            const std::string full = pathToUtf8(candidate);
            if (isRealDirectory(full)) {
                realDir = full;
                filterName.clear();
                return true;
            }
            realDir = parentDir(full);
            filterName = baseName(full);
            return isRealDirectory(realDir);
        }
    }
 
    Info info{};
    if (getInfo(path, info)) {
        std::string root;
        try {
            root = getRealDirectory(path);
        } catch (...) {
            return false;
        }
        std::string full = joinPath(root, path);
        if (info.type == "directory") {
            realDir = full;
            filterName.clear();
            return isRealDirectory(realDir);
        }
        realDir = parentDir(full);
        filterName = baseName(full);
        return isRealDirectory(realDir);
    }
 
    std::string parent = parentDir(path);
    if (parent == ".") parent.clear();
    if (!parent.empty()) {
        Info pinfo{};
        if (getInfo(parent, pinfo) && pinfo.type == "directory") {
            std::string root;
            try {
                root = getRealDirectory(parent);
            } catch (...) {
                return false;
            }
            realDir = joinPath(root, parent);
            filterName = baseName(path);
            return isRealDirectory(realDir);
        }
    }
 
    // Virtual path not in VFS yet (e.g. new file): watch under cwd, not save dir.
    {
        std::string workingDir = getWorkingDirectory();
        if (!workingDir.empty() && isRealDirectory(workingDir)) {
            if (parent.empty()) {
                realDir = workingDir;
                filterName = baseName(path);
                return true;
            }
        }
    }
 
    std::string save = getSaveDirectory();
    if (!save.empty() && isRealDirectory(save)) {
        realDir = save;
        filterName = baseName(path);
        return true;
    }
    return false;
}
 
bool Filesystem::watch(std::string path) {
    std::string realDir, filter, report;
    if (!resolveWatchTarget(path, realDir, filter, report)) return false;
    return watchers().add(realDir, filter, report, 1);
}
 
eve::Result<void> Filesystem::watchRealDirectory(std::string realDir, std::string reportPath) {
    if (realDir.empty() || reportPath.empty()) {
        return eve::Result<void>::failure(eve::Diagnostic::error(
            eve::DiagnosticCode::InvalidArgument,
            "watchRealDirectory requires a real directory and a report path"));
    }
    if (!isRealDirectory(realDir)) {
        return eve::Result<void>::failure(eve::Diagnostic::error(
            eve::DiagnosticCode::NotFound, "watchRealDirectory path is not a directory", realDir));
    }
    if (!watchers().add(std::move(realDir), "", std::move(reportPath), 1)) {
        return eve::Result<void>::failure(eve::Diagnostic::error(
            eve::DiagnosticCode::Failed, "watchRealDirectory could not add an OS watcher"));
    }
    return eve::Result<void>::success();
}
 
bool Filesystem::unwatch(std::string path) { return watchers().remove(path); }
 
void Filesystem::unwatchAll() {
    if (fileWatch_) fileWatch_->clear();
}
 
int Filesystem::getWatchCount() const {
    if (!fileWatch_) return 0;
    return fileWatch_->count();
}
 
std::string Filesystem::pollWatch() {
    if (!fileWatch_) return "";
    FileWatch::Event ev;
    if (!fileWatch_->poll(ev)) {
        lastWatchPath_.clear();
        lastWatchRealPath_.clear();
        return "";
    }
    lastWatchPath_ = ev.path;
    lastWatchRealPath_ = ev.realPath;
    return ev.kind;
}
 
std::string Filesystem::getLastWatchPath() const { return lastWatchPath_; }
std::string Filesystem::getLastWatchRealPath() const { return lastWatchRealPath_; }
 
}  // namespace physfs
}  // namespace filesystem
}  // namespace eve