[libcxx] Cache file attributes during directory iteration.

libcxx/include/__filesystem/directory_entry.h

@@ -201,7 +201,9 @@ class directory_entry {
     _IterNonSymlink,
     _RefreshSymlink,
     _RefreshSymlinkUnresolved,
-    _RefreshNonSymlink
+    _RefreshNonSymlink,
+    _IterCachedSymlink,
+    _IterCachedNonSymlink
   };
 
   struct __cached_data {
@@ -240,6 +242,29 @@ class directory_entry {
     return __data;
   }
 
+  _LIBCPP_HIDE_FROM_ABI static __cached_data
+  __create_iter_cached_result(file_type __ft, uintmax_t __size, perms __perm, file_time_type __write_time) {
+    __cached_data __data;
+    __data.__type_       = __ft;
+    __data.__size_       = __size;
+    __data.__write_time_ = __write_time;
+    if (__ft == file_type::symlink)
+      __data.__sym_perms_ = __perm;
+    else
+      __data.__non_sym_perms_ = __perm;
+    __data.__cache_type_ = [&]() {
+      switch (__ft) {
+      case file_type::none:
+        return _Empty;
+      case file_type::symlink:
+        return _IterCachedSymlink;
+      default:
+        return _IterCachedNonSymlink;
+      }
+    }();
+    return __data;
+  }
+
   _LIBCPP_HIDE_FROM_ABI void __assign_iter_entry(_Path&& __p, __cached_data __dt) {
     __p_    = std::move(__p);
     __data_ = __dt;
@@ -281,29 +306,34 @@ class directory_entry {
     case _Empty:
       return __symlink_status(__p_, __ec).type();
     case _IterSymlink:
+    case _IterCachedSymlink:
     case _RefreshSymlink:
     case _RefreshSymlinkUnresolved:
       if (__ec)
         __ec->clear();
       return file_type::symlink;
+    case _IterCachedNonSymlink:
     case _IterNonSymlink:
-    case _RefreshNonSymlink:
+    case _RefreshNonSymlink: {
       file_status __st(__data_.__type_);
       if (__ec && !filesystem::exists(__st))
         *__ec = make_error_code(errc::no_such_file_or_directory);
       else if (__ec)
         __ec->clear();
       return __data_.__type_;
     }
+    }
     __libcpp_unreachable();
   }
 
   _LIBCPP_HIDE_FROM_ABI file_type __get_ft(error_code* __ec = nullptr) const {
     switch (__data_.__cache_type_) {
     case _Empty:
     case _IterSymlink:
+    case _IterCachedSymlink:
     case _RefreshSymlinkUnresolved:
       return __status(__p_, __ec).type();
+    case _IterCachedNonSymlink:
     case _IterNonSymlink:
     case _RefreshNonSymlink:
     case _RefreshSymlink: {
@@ -323,8 +353,10 @@ class directory_entry {
     case _Empty:
     case _IterNonSymlink:
     case _IterSymlink:
+    case _IterCachedSymlink:
     case _RefreshSymlinkUnresolved:
       return __status(__p_, __ec);
+    case _IterCachedNonSymlink:
     case _RefreshNonSymlink:
     case _RefreshSymlink:
       return file_status(__get_ft(__ec), __data_.__non_sym_perms_);
@@ -338,8 +370,10 @@ class directory_entry {
     case _IterNonSymlink:
     case _IterSymlink:
       return __symlink_status(__p_, __ec);
+    case _IterCachedNonSymlink:
     case _RefreshNonSymlink:
       return file_status(__get_sym_ft(__ec), __data_.__non_sym_perms_);
+    case _IterCachedSymlink:
     case _RefreshSymlink:
     case _RefreshSymlinkUnresolved:
       return file_status(__get_sym_ft(__ec), __data_.__sym_perms_);
@@ -352,8 +386,10 @@ class directory_entry {
     case _Empty:
     case _IterNonSymlink:
     case _IterSymlink:
+    case _IterCachedSymlink:
     case _RefreshSymlinkUnresolved:
       return filesystem::__file_size(__p_, __ec);
+    case _IterCachedNonSymlink:
     case _RefreshSymlink:
     case _RefreshNonSymlink: {
       error_code __m_ec;
@@ -374,6 +410,8 @@ class directory_entry {
     case _Empty:
     case _IterNonSymlink:
     case _IterSymlink:
+    case _IterCachedNonSymlink:
+    case _IterCachedSymlink:
     case _RefreshSymlinkUnresolved:
       return filesystem::__hard_link_count(__p_, __ec);
     case _RefreshSymlink:
@@ -392,8 +430,10 @@ class directory_entry {
     case _Empty:
     case _IterNonSymlink:
     case _IterSymlink:
+    case _IterCachedSymlink:
     case _RefreshSymlinkUnresolved:
       return filesystem::__last_write_time(__p_, __ec);
+    case _IterCachedNonSymlink:
     case _RefreshSymlink:
     case _RefreshNonSymlink: {
       error_code __m_ec;

libcxx/src/filesystem/directory_iterator.cpp

@@ -77,13 +77,13 @@ class __dir_stream {
   bool assign() {
     if (!wcscmp(__data_.cFileName, L".") || !wcscmp(__data_.cFileName, L".."))
       return false;
-    // FIXME: Cache more of this
-    // directory_entry::__cached_data cdata;
-    // cdata.__type_ = get_file_type(__data_);
-    // cdata.__size_ = get_file_size(__data_);
-    // cdata.__write_time_ = get_write_time(__data_);
     __entry_.__assign_iter_entry(
-        __root_ / __data_.cFileName, directory_entry::__create_iter_result(detail::get_file_type(__data_)));
+        __root_ / __data_.cFileName,
+        directory_entry::__create_iter_cached_result(
+            detail::get_file_type(__data_),
+            detail::get_file_size(__data_),
+            detail::get_file_perm(__data_),
+            detail::get_write_time(__data_)));
     return true;
   }
 

libcxx/src/filesystem/file_descriptor.h

@@ -97,11 +97,18 @@ inline uintmax_t get_file_size(const WIN32_FIND_DATAW& data) {
   return (static_cast<uint64_t>(data.nFileSizeHigh) << 32) + data.nFileSizeLow;
 }
 inline file_time_type get_write_time(const WIN32_FIND_DATAW& data) {
-  ULARGE_INTEGER tmp;
+  using detail::fs_time;
   const FILETIME& time = data.ftLastWriteTime;
-  tmp.u.LowPart        = time.dwLowDateTime;
-  tmp.u.HighPart       = time.dwHighDateTime;
-  return file_time_type(file_time_type::duration(tmp.QuadPart));
+  auto ts              = filetime_to_timespec(time);
+  if (!fs_time::is_representable(ts))
+    return file_time_type::min();
+  return fs_time::convert_from_timespec(ts);
+}
+inline perms get_file_perm(const WIN32_FIND_DATAW& data) {
+  unsigned st_mode = 0555; // Read-only
+  if (!(data.dwFileAttributes & FILE_ATTRIBUTE_READONLY))
+    st_mode |= 0222; // Write
+  return static_cast<perms>(st_mode) & perms::mask;
 }
 
 #endif // !_LIBCPP_WIN32API

libcxx/test/std/input.output/filesystems/class.rec.dir.itr/cache_refresh_iter.pass.cpp

@@ -0,0 +1,187 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// REQUIRES: can-create-symlinks
+// UNSUPPORTED: c++03, c++11, c++14
+// UNSUPPORTED: no-filesystem
+// UNSUPPORTED: availability-filesystem-missing
+
+// <filesystem>
+
+// recursive_directory_iterator
+
+#include <filesystem>
+#include <type_traits>
+#include <set>
+#include <cassert>
+
+#include "test_macros.h"
+#include "filesystem_test_helper.h"
+namespace fs = std::filesystem;
+
+#if defined(_WIN32)
+static void set_last_write_time_in_iteration(const fs::path& dir) {
+  // Windows can postpone updating last write time for file especially for
+  // directory because last write time of directory depends of its childs.
+  // See
+  // https://learn.microsoft.com/en-us/windows/win32/sysinfo/file-times
+  // To force updating file entries calls "last_write_time" with own value.
+  const fs::recursive_directory_iterator end_it{};
+
+  std::error_code ec;
+  fs::recursive_directory_iterator it(dir, ec);
+  assert(!ec);
+
+  fs::file_time_type now_time = fs::file_time_type::clock::now();
+  for (; it != end_it; ++it) {
+    const fs::path entry = *it;
+    fs::last_write_time(entry, now_time, ec);
+    assert(!ec);
+  }
+
+  assert(it == end_it);
+}
+
+struct directory_entry_and_values {
+  fs::directory_entry entry;
+
+  fs::file_status symlink_status;
+  fs::file_status status;
+  std::uintmax_t file_size;
+  fs::file_time_type last_write_time;
+};
+
+std::vector<directory_entry_and_values>
+get_directory_entries_for(const fs::path& dir, const std::set<fs::path>& dir_contents) {
+  const fs::recursive_directory_iterator end_it{};
+
+  std::error_code ec;
+  fs::recursive_directory_iterator it(dir, ec);
+  assert(!ec);
+
+  std::vector<directory_entry_and_values> dir_entries;
+  std::set<fs::path> unseen_entries = dir_contents;
+  while (!unseen_entries.empty()) {
+    assert(it != end_it);
+    const fs::directory_entry& entry = *it;
+
+    assert(unseen_entries.erase(entry.path()) == 1);
+
+    dir_entries.push_back(directory_entry_and_values{
+        .entry           = entry,
+        .symlink_status  = entry.symlink_status(),
+        .status          = entry.status(),
+        .file_size       = entry.is_regular_file() ? entry.file_size() : 0,
+        .last_write_time = entry.last_write_time()});
+
+    fs::recursive_directory_iterator& it_ref = it.increment(ec);
+    assert(!ec);
+    assert(&it_ref == &it);
+  }
+  return dir_entries;
+}
+#endif // _WIN32
+
+// Checks that the directory_entry properties will be the same before and after
+// calling "refresh" in case of iteration.
+// In case of Windows expects that directory_entry caches the properties during
+// iteration.
+static void test_cache_and_refresh_in_iteration() {
+  static_test_env static_env;
+  const fs::path test_dir = static_env.Dir;
+#if defined(_WIN32)
+  set_last_write_time_in_iteration(test_dir);
+#endif
+  const std::set<fs::path> dir_contents(static_env.RecDirIterationList.begin(), static_env.RecDirIterationList.end());
+  const fs::recursive_directory_iterator end_it{};
+
+  std::error_code ec;
+  fs::recursive_directory_iterator it(test_dir, ec);
+  assert(!ec);
+
+  std::set<fs::path> unseen_entries = dir_contents;
+  while (!unseen_entries.empty()) {
+    assert(it != end_it);
+    const fs::directory_entry& entry = *it;
+
+    assert(unseen_entries.erase(entry.path()) == 1);
+
+    fs::file_status symlink_status     = entry.symlink_status();
+    fs::file_status status             = entry.status();
+    std::uintmax_t file_size           = entry.is_regular_file() ? entry.file_size() : 0;
+    fs::file_time_type last_write_time = entry.last_write_time();
+
+    fs::directory_entry mutable_entry = *it;
+    mutable_entry.refresh();
+    fs::file_status upd_symlink_status     = mutable_entry.symlink_status();
+    fs::file_status upd_status             = mutable_entry.status();
+    std::uintmax_t upd_file_size           = mutable_entry.is_regular_file() ? mutable_entry.file_size() : 0;
+    fs::file_time_type upd_last_write_time = mutable_entry.last_write_time();
+    assert(upd_symlink_status.type() == symlink_status.type() &&
+           upd_symlink_status.permissions() == symlink_status.permissions());
+    assert(upd_status.type() == status.type() && upd_status.permissions() == status.permissions());
+    assert(upd_file_size == file_size);
+    assert(upd_last_write_time == last_write_time);
+
+    fs::recursive_directory_iterator& it_ref = it.increment(ec);
+    assert(!ec);
+    assert(&it_ref == &it);
+  }
+}
+
+#if defined(_WIN32)
+// In case of Windows expects that the directory_entry caches the properties
+// during iteration and the properties don't change after deleting folders
+// and files.
+static void test_cached_values_in_iteration() {
+  std::vector<directory_entry_and_values> dir_entries;
+  {
+    static_test_env static_env;
+    const fs::path testDir = static_env.Dir;
+    set_last_write_time_in_iteration(testDir);
+    const std::set<fs::path> dir_contents(static_env.RecDirIterationList.begin(), static_env.RecDirIterationList.end());
+    dir_entries = get_directory_entries_for(testDir, dir_contents);
+  }
+  // Testing folder should be deleted after destoying static_test_env.
+
+  for (const auto& dir_entry : dir_entries) {
+    // During iteration Windows provides information only about symlink itself
+    // not about file/folder which symlink points to.
+    if (dir_entry.entry.is_symlink()) {
+      // Check that symlink is not using cached value about existing file.
+      assert(!dir_entry.entry.exists());
+    } else {
+      // Check that entry uses cached value about existing file.
+      assert(dir_entry.entry.exists());
+    }
+    fs::file_status symlink_status = dir_entry.entry.symlink_status();
+    assert(dir_entry.symlink_status.type() == symlink_status.type() &&
+           dir_entry.symlink_status.permissions() == symlink_status.permissions());
+
+    if (!dir_entry.entry.is_symlink()) {
+      fs::file_status status = dir_entry.entry.status();
+      assert(dir_entry.status.type() == status.type() && dir_entry.status.permissions() == status.permissions());
+
+      std::uintmax_t file_size = dir_entry.entry.is_regular_file() ? dir_entry.entry.file_size() : 0;
+      assert(dir_entry.file_size == file_size);
+
+      fs::file_time_type last_write_time = dir_entry.entry.last_write_time();
+      assert(dir_entry.last_write_time == last_write_time);
+    }
+  }
+}
+#endif // _WIN32
+
+int main(int, char**) {
+  test_cache_and_refresh_in_iteration();
+#if defined(_WIN32)
+  test_cached_values_in_iteration();
+#endif
+
+  return 0;
+}