file_util: Fix file behaviour on Windows (#1841)

src/common/file_util.cpp

@@ -211,10 +211,33 @@ bool Delete(const std::string& filename) {
     }
 
 #ifdef _WIN32
-    if (!DeleteFileW(Common::UTF8ToUTF16W(filename).c_str())) {
-        LOG_ERROR(Common_Filesystem, "DeleteFile failed on {}: {}", filename, GetLastErrorMsg());
-        return false;
+    // On windows, if we delete a file with an open handle (pending to be deleted) and
+    // then try to open the same file name again, it will fail. On linux this doesn't happen
+    // as the new file will be a different inode, even if it has the same file name.
+    // The 3ds is linux-like, so to emulate this behaviour we need to rename the file
+    // first to an unique name then mark it for deletion. This way we can open new files
+    // with the same name. Once all handles of the old file are closed, the old file will be
+    // finally deleted.
+    static std::atomic<uint64_t> counter{0};
+
+    const std::wstring wfilename = Common::UTF8ToUTF16W(filename);
+    const DWORD pid = GetCurrentProcessId();
+    const uint64_t id = counter++;
+
+    std::wstring deleted_path =
+        wfilename + L".deleted." + std::to_wstring(pid) + L"." + std::to_wstring(id);
+
+    // Rename first
+    if (MoveFileExW(wfilename.c_str(), deleted_path.c_str(), MOVEFILE_REPLACE_EXISTING)) {
+        // Then mark file for deletion
+        DeleteFileW(deleted_path.c_str());
+        return true;
     }
+
+    LOG_ERROR(Common_Filesystem, "Rename to deleted path failed on {}: {}", filename,
+              GetLastErrorMsg());
+
+    return false;
 #elif defined(ANDROID) && !defined(HAVE_LIBRETRO_VFS)
     if (!AndroidStorage::DeleteDocument(filename)) {
         LOG_ERROR(Common_Filesystem, "unlink failed on {}", filename);
@@ -344,9 +367,10 @@ bool DeleteDir(const std::string& filename) {
 bool Rename(const std::string& srcFullPath, const std::string& destFullPath) {
     LOG_TRACE(Common_Filesystem, "{} --> {}", srcFullPath, destFullPath);
 #ifdef _WIN32
-    if (_wrename(Common::UTF8ToUTF16W(srcFullPath).c_str(),
-                 Common::UTF8ToUTF16W(destFullPath).c_str()) == 0)
+    if (MoveFileExW(Common::UTF8ToUTF16W(srcFullPath).c_str(),
+                    Common::UTF8ToUTF16W(destFullPath).c_str(), MOVEFILE_REPLACE_EXISTING)) {
         return true;
+    }
 #elif defined(ANDROID) && !defined(HAVE_LIBRETRO_VFS)
     // srcFullPath and destFullPath are relative to the user directory
     if (AndroidStorage::GetBuildFlavor() == AndroidStorage::AndroidBuildFlavors::GOOGLEPLAY) {
@@ -1167,11 +1191,46 @@ bool IOFile::Open() {
     Close();
 
 #ifdef _WIN32
-    if (flags == 0) {
-        flags = _SH_DENYNO;
+    // Open with FILE_SHARE_READ, FILE_SHARE_WRITE and FILE_SHARE_DELETE
+    // flags. This mimics linux behaviour as much as possible, which
+    // the 3DS also does.
+
+    const std::wstring wfilename = Common::UTF8ToUTF16W(filename);
+
+    DWORD access = 0;
+    DWORD creation = OPEN_EXISTING;
+
+    if (openmode.find("r") != std::string::npos)
+        access |= GENERIC_READ;
+    if (openmode.find("w") != std::string::npos) {
+        access |= GENERIC_WRITE;
+        creation = CREATE_ALWAYS;
     }
-    m_file = _wfsopen(Common::UTF8ToUTF16W(filename).c_str(),
-                      Common::UTF8ToUTF16W(openmode).c_str(), flags);
+    if (openmode.find("a") != std::string::npos) {
+        access |= FILE_APPEND_DATA;
+        creation = OPEN_ALWAYS;
+    }
+    if (openmode.find("+") != std::string::npos) {
+        access |= GENERIC_READ | GENERIC_WRITE;
+    }
+
+    HANDLE h = CreateFileW(wfilename.c_str(), access,
+                           FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, nullptr,
+                           creation, FILE_ATTRIBUTE_NORMAL, nullptr);
+
+    if (h == INVALID_HANDLE_VALUE) {
+        m_good = false;
+        return false;
+    }
+
+    int fd = _open_osfhandle(reinterpret_cast<intptr_t>(h), 0);
+    if (fd == -1) {
+        CloseHandle(h);
+        m_good = false;
+        return m_good;
+    }
+
+    m_file = _fdopen(fd, openmode.c_str());
     m_good = m_file != nullptr;
 
 #elif defined(ANDROID) && !defined(HAVE_LIBRETRO_VFS)

src/core/core.cpp

@@ -469,7 +469,6 @@ System::ResultStatus System::Load(Frontend::EmuWindow& emu_window, const std::st
     m_emu_window = &emu_window;
     m_secondary_window = secondary_window;
     m_filepath = filepath;
-    self_delete_pending = false;
 
     // Reset counters and set time origin to current frame
     [[maybe_unused]] const PerfStats::Results result = GetAndResetPerfStats();
@@ -721,10 +720,6 @@ void System::Shutdown(bool is_deserializing) {
 
     memory.reset();
 
-    if (self_delete_pending)
-        FileUtil::Delete(m_filepath);
-    self_delete_pending = false;
-
     LOG_DEBUG(Core, "Shutdown OK");
 }
 

src/core/core.h

@@ -366,15 +366,6 @@ public:
 
     bool LoadStateBuffer(std::vector<u8> buffer);
 
-    /// Self delete ncch
-    bool SetSelfDelete(const std::string& file) {
-        if (m_filepath == file) {
-            self_delete_pending = true;
-            return true;
-        }
-        return false;
-    }
-
     /// Applies any changes to settings to this core instance.
     void ApplySettings();
 
@@ -480,7 +471,6 @@ private:
     std::string m_chainloadpath;
     std::optional<u8> m_mem_mode;
     u64 title_id;
-    bool self_delete_pending;
 
     std::mutex signal_mutex;
     Signal current_signal;

src/core/hle/service/am/am.cpp

@@ -916,15 +916,7 @@ bool CIAFile::Close() {
             if (abort) {
                 break;
             }
-
-            // If the file to delete is the current launched rom, signal the system to delete
-            // the current rom instead of deleting it now, once all the handles to the file
-            // are closed.
-            std::string to_delete =
-                GetTitleContentPath(media_type, old_tmd.GetTitleID(), old_index);
-            if (!system.IsPoweredOn() || !system.SetSelfDelete(to_delete)) {
-                FileUtil::Delete(to_delete);
-            }
+            FileUtil::Delete(GetTitleContentPath(media_type, old_tmd.GetTitleID(), old_index));
         }
 
         FileUtil::Delete(old_tmd_path);