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dolphin/Externals/WIL/include/wil/filesystem.h

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//*********************************************************
//
// Copyright (c) Microsoft. All rights reserved.
// This code is licensed under the MIT License.
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
// ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
// TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
// PARTICULAR PURPOSE AND NONINFRINGEMENT.
//
//*********************************************************
#ifndef __WIL_FILESYSTEM_INCLUDED
#define __WIL_FILESYSTEM_INCLUDED
#ifdef _KERNEL_MODE
#error This header is not supported in kernel-mode.
#endif
#include <new>
#include <combaseapi.h> // Needed for CoTaskMemFree() used in output of some helpers.
#include <winbase.h> // LocalAlloc
#include <PathCch.h>
#include "result.h"
#include "win32_helpers.h"
#include "resource.h"
namespace wil
{
//! Determines if a path is an extended length path that can be used to access paths longer than MAX_PATH.
inline bool is_extended_length_path(_In_ PCWSTR path)
{
return wcsncmp(path, L"\\\\?\\", 4) == 0;
}
#if (_WIN32_WINNT >= _WIN32_WINNT_WIN7)
//! Find the last segment of a path. Matches the behavior of shlwapi!PathFindFileNameW()
//! note, does not support streams being specified like PathFindFileNameW(), is that a bug or a feature?
inline PCWSTR find_last_path_segment(_In_ PCWSTR path)
{
auto const pathLength = wcslen(path);
// If there is a trailing slash ignore that in the search.
auto const limitedLength = ((pathLength > 0) && (path[pathLength - 1] == L'\\')) ? (pathLength - 1) : pathLength;
PCWSTR result;
auto const offset = FindStringOrdinal(FIND_FROMEND, path, static_cast<int>(limitedLength), L"\\", 1, TRUE);
if (offset == -1)
{
result = path + pathLength; // null terminator
}
else
{
result = path + offset + 1; // just past the slash
}
return result;
}
#endif
//! Determine if the file name is one of the special "." or ".." names.
inline bool path_is_dot_or_dotdot(_In_ PCWSTR fileName)
{
return ((fileName[0] == L'.') &&
((fileName[1] == L'\0') || ((fileName[1] == L'.') && (fileName[2] == L'\0'))));
}
//! Returns the drive number, if it has one. Returns true if there is a drive number, false otherwise. Supports regular and extended length paths.
inline bool try_get_drive_letter_number(_In_ PCWSTR path, _Out_ int* driveNumber)
{
if (path[0] == L'\\' && path[1] == L'\\' && path[2] == L'?' && path[3] == L'\\')
{
path += 4;
}
if (path[0] && (path[1] == L':'))
{
if ((path[0] >= L'a') && (path[0] <= L'z'))
{
*driveNumber = path[0] - L'a';
return true;
}
else if ((path[0] >= L'A') && (path[0] <= L'Z'))
{
*driveNumber = path[0] - L'A';
return true;
}
}
*driveNumber = -1;
return false;
}
#if WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP) && (_WIN32_WINNT >= _WIN32_WINNT_WIN7)
// PathCch.h APIs are only in desktop API for now.
// Compute the substring in the input value that is the parent folder path.
// returns:
// true + parentPathLength - path has a parent starting at the beginning path and of parentPathLength length.
// false, no parent path, the input is a root path.
inline bool try_get_parent_path_range(_In_ PCWSTR path, _Out_ size_t* parentPathLength)
{
*parentPathLength = 0;
bool hasParent = false;
PCWSTR rootEnd;
if (SUCCEEDED(PathCchSkipRoot(path, &rootEnd)) && (*rootEnd != L'\0'))
{
auto const lastSegment = find_last_path_segment(path);
*parentPathLength = lastSegment - path;
hasParent = (*parentPathLength != 0);
}
return hasParent;
}
// Creates directories for the specified path, creating parent paths
// as needed.
inline HRESULT CreateDirectoryDeepNoThrow(PCWSTR path) WI_NOEXCEPT
{
if (::CreateDirectoryW(path, nullptr) == FALSE)
{
DWORD lastError = ::GetLastError();
if (lastError == ERROR_PATH_NOT_FOUND)
{
size_t parentLength;
if (try_get_parent_path_range(path, &parentLength))
{
wistd::unique_ptr<wchar_t[]> parent(new (std::nothrow) wchar_t[parentLength + 1]);
RETURN_IF_NULL_ALLOC(parent.get());
RETURN_IF_FAILED(StringCchCopyNW(parent.get(), parentLength + 1, path, parentLength));
RETURN_IF_FAILED(CreateDirectoryDeepNoThrow(parent.get())); // recurs
}
if (::CreateDirectoryW(path, nullptr) == FALSE)
{
lastError = ::GetLastError();
if (lastError != ERROR_ALREADY_EXISTS)
{
RETURN_WIN32(lastError);
}
}
}
else if (lastError != ERROR_ALREADY_EXISTS)
{
RETURN_WIN32(lastError);
}
}
return S_OK;
}
#ifdef WIL_ENABLE_EXCEPTIONS
inline void CreateDirectoryDeep(PCWSTR path)
{
THROW_IF_FAILED(CreateDirectoryDeepNoThrow(path));
}
#endif // WIL_ENABLE_EXCEPTIONS
//! A strongly typed version of the Win32 API GetFullPathNameW.
//! Return a path in an allocated buffer for handling long paths.
//! Optionally return the pointer to the file name part.
template <typename string_type, size_t stackBufferLength = 256>
HRESULT GetFullPathNameW(PCWSTR file, string_type& path, _Outptr_opt_ PCWSTR* filePart = nullptr)
{
wil::assign_null_to_opt_param(filePart);
const auto hr = AdaptFixedSizeToAllocatedResult<string_type, stackBufferLength>(path,
[&](_Out_writes_(valueLength) PWSTR value, size_t valueLength, _Out_ size_t* valueLengthNeededWithNull) -> HRESULT
{
// Note that GetFullPathNameW() is not limited to MAX_PATH
// but it does take a fixed size buffer.
*valueLengthNeededWithNull = ::GetFullPathNameW(file, static_cast<DWORD>(valueLength), value, nullptr);
RETURN_LAST_ERROR_IF(*valueLengthNeededWithNull == 0);
WI_ASSERT((*value != L'\0') == (*valueLengthNeededWithNull < valueLength));
if (*valueLengthNeededWithNull < valueLength)
{
(*valueLengthNeededWithNull)++; // it fit, account for the null
}
return S_OK;
});
if (SUCCEEDED(hr) && filePart)
{
*filePart = wil::find_last_path_segment(details::string_maker<string_type>::get(path));
}
return hr;
}
#ifdef WIL_ENABLE_EXCEPTIONS
//! A strongly typed version of the Win32 API of GetFullPathNameW.
//! Return a path in an allocated buffer for handling long paths.
//! Optionally return the pointer to the file name part.
template <typename string_type = wil::unique_cotaskmem_string, size_t stackBufferLength = 256>
string_type GetFullPathNameW(PCWSTR file, _Outptr_opt_ PCWSTR* filePart = nullptr)
{
string_type result;
THROW_IF_FAILED((GetFullPathNameW<string_type, stackBufferLength>(file, result, filePart)));
return result;
}
#endif
enum class RemoveDirectoryOptions
{
None = 0,
KeepRootDirectory = 0x1,
RemoveReadOnly = 0x2,
};
DEFINE_ENUM_FLAG_OPERATORS(RemoveDirectoryOptions);
namespace details
{
// Reparse points should not be traversed in most recursive walks of the file system,
// unless allowed through the appropriate reparse tag.
inline bool CanRecurseIntoDirectory(const FILE_ATTRIBUTE_TAG_INFO& info)
{
return (WI_IsFlagSet(info.FileAttributes, FILE_ATTRIBUTE_DIRECTORY) &&
(WI_IsFlagClear(info.FileAttributes, FILE_ATTRIBUTE_REPARSE_POINT) ||
(IsReparseTagDirectory(info.ReparseTag) || (info.ReparseTag == IO_REPARSE_TAG_WCI))));
}
}
// Retrieve a handle to a directory only if it is safe to recurse into.
inline wil::unique_hfile TryCreateFileCanRecurseIntoDirectory(PCWSTR path, PWIN32_FIND_DATAW fileFindData, DWORD access = GENERIC_READ | /*DELETE*/ 0x00010000L, DWORD share = FILE_SHARE_READ)
{
wil::unique_hfile result(CreateFileW(path, access, share,
nullptr, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OPEN_REPARSE_POINT, nullptr));
if (result)
{
FILE_ATTRIBUTE_TAG_INFO fati;
if (GetFileInformationByHandleEx(result.get(), FileAttributeTagInfo, &fati, sizeof(fati)) &&
details::CanRecurseIntoDirectory(fati))
{
if (fileFindData)
{
// Refresh the found file's data now that we have secured the directory from external manipulation.
fileFindData->dwFileAttributes = fati.FileAttributes;
fileFindData->dwReserved0 = fati.ReparseTag;
}
}
else
{
result.reset();
}
}
return result;
}
// If inputPath is a non-normalized name be sure to pass an extended length form to ensure
// it can be addressed and deleted.
inline HRESULT RemoveDirectoryRecursiveNoThrow(PCWSTR inputPath, RemoveDirectoryOptions options = RemoveDirectoryOptions::None, HANDLE deleteHandle = INVALID_HANDLE_VALUE) WI_NOEXCEPT
{
wil::unique_hlocal_string path;
PATHCCH_OPTIONS combineOptions = PATHCCH_NONE;
if (is_extended_length_path(inputPath))
{
path = wil::make_hlocal_string_nothrow(inputPath);
RETURN_IF_NULL_ALLOC(path);
// PathAllocCombine will convert extended length paths to regular paths if shorter than
// MAX_PATH, avoid that behavior to provide access inputPath with non-normalized names.
combineOptions = PATHCCH_ENSURE_IS_EXTENDED_LENGTH_PATH;
}
else
{
// For regular paths normalize here to get consistent results when searching and deleting.
RETURN_IF_FAILED(wil::GetFullPathNameW(inputPath, path));
combineOptions = PATHCCH_ALLOW_LONG_PATHS;
}
wil::unique_hlocal_string searchPath;
RETURN_IF_FAILED(::PathAllocCombine(path.get(), L"*", combineOptions, &searchPath));
WIN32_FIND_DATAW fd;
wil::unique_hfind findHandle(::FindFirstFileW(searchPath.get(), &fd));
RETURN_LAST_ERROR_IF(!findHandle);
for (;;)
{
// skip "." and ".."
if (!(WI_IsFlagSet(fd.dwFileAttributes, FILE_ATTRIBUTE_DIRECTORY) && path_is_dot_or_dotdot(fd.cFileName)))
{
// Need to form an extended length path to provide the ability to delete paths > MAX_PATH
// and files with non-normalized names (dots or spaces at the end).
wil::unique_hlocal_string pathToDelete;
RETURN_IF_FAILED(::PathAllocCombine(path.get(), fd.cFileName,
PATHCCH_ENSURE_IS_EXTENDED_LENGTH_PATH | PATHCCH_DO_NOT_NORMALIZE_SEGMENTS, &pathToDelete));
if (WI_IsFlagSet(fd.dwFileAttributes, FILE_ATTRIBUTE_DIRECTORY))
{
// Get a handle to the directory to delete, preventing it from being replaced to prevent writes which could be used
// to bypass permission checks, and verify that it is not a name surrogate (e.g. symlink, mount point, etc).
wil::unique_hfile recursivelyDeletableDirectoryHandle = TryCreateFileCanRecurseIntoDirectory(pathToDelete.get(), &fd);
if (recursivelyDeletableDirectoryHandle)
{
RemoveDirectoryOptions localOptions = options;
RETURN_IF_FAILED(RemoveDirectoryRecursiveNoThrow(pathToDelete.get(), WI_ClearFlag(localOptions, RemoveDirectoryOptions::KeepRootDirectory), recursivelyDeletableDirectoryHandle.get()));
}
else if (WI_IsFlagSet(fd.dwFileAttributes, FILE_ATTRIBUTE_REPARSE_POINT))
{
// This is a directory reparse point that should not be recursed. Delete it without traversing into it.
RETURN_IF_WIN32_BOOL_FALSE(::RemoveDirectoryW(pathToDelete.get()));
}
else
{
// Failed to grab a handle to the file or to read its attributes. This is not safe to recurse.
RETURN_WIN32(::GetLastError());
}
}
else
{
// Try a DeleteFile. Some errors may be recoverable.
if (!::DeleteFileW(pathToDelete.get()))
{
// Fail for anything other than ERROR_ACCESS_DENIED with option to RemoveReadOnly available
bool potentiallyFixableReadOnlyProblem =
WI_IsFlagSet(options, RemoveDirectoryOptions::RemoveReadOnly) && ::GetLastError() == ERROR_ACCESS_DENIED;
RETURN_LAST_ERROR_IF(!potentiallyFixableReadOnlyProblem);
// Fail if the file does not have read-only set, likely just an ACL problem
DWORD fileAttr = ::GetFileAttributesW(pathToDelete.get());
RETURN_LAST_ERROR_IF(!WI_IsFlagSet(fileAttr, FILE_ATTRIBUTE_READONLY));
// Remove read-only flag, setting to NORMAL if completely empty
WI_ClearFlag(fileAttr, FILE_ATTRIBUTE_READONLY);
if (fileAttr == 0)
{
fileAttr = FILE_ATTRIBUTE_NORMAL;
}
// Set the new attributes and try to delete the file again, returning any failure
::SetFileAttributesW(pathToDelete.get(), fileAttr);
RETURN_IF_WIN32_BOOL_FALSE(::DeleteFileW(pathToDelete.get()));
}
}
}
if (!::FindNextFileW(findHandle.get(), &fd))
{
auto const err = ::GetLastError();
if (err == ERROR_NO_MORE_FILES)
{
break;
}
RETURN_WIN32(err);
}
}
if (WI_IsFlagClear(options, RemoveDirectoryOptions::KeepRootDirectory))
{
if (deleteHandle != INVALID_HANDLE_VALUE)
{
#if (NTDDI_VERSION >= NTDDI_WIN10_RS1)
// DeleteFile and RemoveDirectory use POSIX delete, falling back to non-POSIX on most errors. Do the same here.
FILE_DISPOSITION_INFO_EX fileInfoEx{};
fileInfoEx.Flags = FILE_DISPOSITION_FLAG_DELETE | FILE_DISPOSITION_FLAG_POSIX_SEMANTICS;
if (!SetFileInformationByHandle(deleteHandle, FileDispositionInfoEx, &fileInfoEx, sizeof(fileInfoEx)))
{
auto const err = ::GetLastError();
// The real error we're looking for is STATUS_CANNOT_DELETE, but that's mapped to ERROR_ACCESS_DENIED.
if (err != ERROR_ACCESS_DENIED)
{
#endif
FILE_DISPOSITION_INFO fileInfo{};
fileInfo.DeleteFile = TRUE;
RETURN_IF_WIN32_BOOL_FALSE(SetFileInformationByHandle(deleteHandle, FileDispositionInfo, &fileInfo, sizeof(fileInfo)));
#if (NTDDI_VERSION >= NTDDI_WIN10_RS1)
}
else
{
RETURN_WIN32(err);
}
}
#endif
}
else
{
RETURN_IF_WIN32_BOOL_FALSE(::RemoveDirectoryW(path.get()));
}
}
return S_OK;
}
#ifdef WIL_ENABLE_EXCEPTIONS
inline void RemoveDirectoryRecursive(PCWSTR path, RemoveDirectoryOptions options = RemoveDirectoryOptions::None)
{
THROW_IF_FAILED(RemoveDirectoryRecursiveNoThrow(path, options));
}
#endif // WIL_ENABLE_EXCEPTIONS
// Range based for that supports Win32 structures that use NextEntryOffset as the basis of traversing
// a result buffer that contains data. This is used in the following FileIO calls:
// FileStreamInfo, FILE_STREAM_INFO
// FileIdBothDirectoryInfo, FILE_ID_BOTH_DIR_INFO
// FileFullDirectoryInfo, FILE_FULL_DIR_INFO
// FileIdExtdDirectoryInfo, FILE_ID_EXTD_DIR_INFO
// ReadDirectoryChangesW, FILE_NOTIFY_INFORMATION
template <typename T>
struct next_entry_offset_iterator
{
// Fulfill std::iterator_traits requirements
using difference_type = ptrdiff_t;
using value_type = T;
using pointer = const T*;
using reference = const T&;
#ifdef _XUTILITY_
using iterator_category = ::std::forward_iterator_tag;
#endif
next_entry_offset_iterator(T *iterable = __nullptr) : current_(iterable) {}
// range based for requires operator!=, operator++ and operator* to do its work
// on the type returned from begin() and end(), provide those here.
bool operator!=(const next_entry_offset_iterator& other) const { return current_ != other.current_; }
next_entry_offset_iterator& operator++()
{
current_ = (current_->NextEntryOffset != 0) ?
reinterpret_cast<T *>(reinterpret_cast<unsigned char*>(current_) + current_->NextEntryOffset) :
__nullptr;
return *this;
}
next_entry_offset_iterator operator++(int)
{
auto copy = *this;
++(*this);
return copy;
}
reference operator*() const WI_NOEXCEPT { return *current_; }
pointer operator->() const WI_NOEXCEPT { return current_; }
next_entry_offset_iterator<T> begin() { return *this; }
next_entry_offset_iterator<T> end() { return next_entry_offset_iterator<T>(); }
T* current_;
};
template <typename T>
next_entry_offset_iterator<T> create_next_entry_offset_iterator(T* p)
{
return next_entry_offset_iterator<T>(p);
}
#pragma region Folder Watcher
// Example use in exception based code:
// auto watcher = wil::make_folder_watcher(folder.Path().c_str(), true, wil::allChangeEvents, []()
// {
// // respond
// });
//
// Example use in result code based code:
// wil::unique_folder_watcher watcher;
// THROW_IF_FAILED(watcher.create(folder, true, wil::allChangeEvents, []()
// {
// // respond
// }));
enum class FolderChangeEvent : DWORD
{
ChangesLost = 0, // requies special handling, reset state as events were lost
Added = FILE_ACTION_ADDED,
Removed = FILE_ACTION_REMOVED,
Modified = FILE_ACTION_MODIFIED,
RenameOldName = FILE_ACTION_RENAMED_OLD_NAME,
RenameNewName = FILE_ACTION_RENAMED_NEW_NAME,
};
enum class FolderChangeEvents : DWORD
{
None = 0,
FileName = FILE_NOTIFY_CHANGE_FILE_NAME,
DirectoryName = FILE_NOTIFY_CHANGE_DIR_NAME,
Attributes = FILE_NOTIFY_CHANGE_ATTRIBUTES,
FileSize = FILE_NOTIFY_CHANGE_SIZE,
LastWriteTime = FILE_NOTIFY_CHANGE_LAST_WRITE,
Security = FILE_NOTIFY_CHANGE_SECURITY,
All = FILE_NOTIFY_CHANGE_FILE_NAME |
FILE_NOTIFY_CHANGE_DIR_NAME |
FILE_NOTIFY_CHANGE_ATTRIBUTES |
FILE_NOTIFY_CHANGE_SIZE |
FILE_NOTIFY_CHANGE_LAST_WRITE |
FILE_NOTIFY_CHANGE_SECURITY
};
DEFINE_ENUM_FLAG_OPERATORS(FolderChangeEvents);
/// @cond
namespace details
{
struct folder_watcher_state
{
folder_watcher_state(wistd::function<void()> &&callback) : m_callback(wistd::move(callback))
{
}
wistd::function<void()> m_callback;
// Order is important, need to close the thread pool wait before the change handle.
unique_hfind_change m_findChangeHandle;
unique_threadpool_wait m_threadPoolWait;
};
inline void delete_folder_watcher_state(_In_opt_ folder_watcher_state *storage) { delete storage; }
typedef resource_policy<folder_watcher_state *, decltype(&details::delete_folder_watcher_state),
details::delete_folder_watcher_state, details::pointer_access_none> folder_watcher_state_resource_policy;
}
/// @endcond
template <typename storage_t, typename err_policy = err_exception_policy>
class folder_watcher_t : public storage_t
{
public:
// forward all base class constructors...
template <typename... args_t>
explicit folder_watcher_t(args_t&&... args) WI_NOEXCEPT : storage_t(wistd::forward<args_t>(args)...) {}
// HRESULT or void error handling...
typedef typename err_policy::result result;
// Exception-based constructors
folder_watcher_t(PCWSTR folderToWatch, bool isRecursive, FolderChangeEvents filter, wistd::function<void()> &&callback)
{
static_assert(wistd::is_same<void, result>::value, "this constructor requires exceptions; use the create method");
create(folderToWatch, isRecursive, filter, wistd::move(callback));
}
result create(PCWSTR folderToWatch, bool isRecursive, FolderChangeEvents filter, wistd::function<void()> &&callback)
{
return err_policy::HResult(create_common(folderToWatch, isRecursive, filter, wistd::move(callback)));
}
private:
// Factored into a standalone function to support Clang which does not support conversion of stateless lambdas
// to __stdcall
static void __stdcall callback(PTP_CALLBACK_INSTANCE /*Instance*/, void *context, TP_WAIT *pThreadPoolWait, TP_WAIT_RESULT /*result*/)
{
auto watcherState = static_cast<details::folder_watcher_state *>(context);
watcherState->m_callback();
// Rearm the wait. Should not fail with valid parameters.
FindNextChangeNotification(watcherState->m_findChangeHandle.get());
SetThreadpoolWait(pThreadPoolWait, watcherState->m_findChangeHandle.get(), __nullptr);
}
// This function exists to avoid template expansion of this code based on err_policy.
HRESULT create_common(PCWSTR folderToWatch, bool isRecursive, FolderChangeEvents filter, wistd::function<void()> &&callback)
{
wistd::unique_ptr<details::folder_watcher_state> watcherState(new(std::nothrow) details::folder_watcher_state(wistd::move(callback)));
RETURN_IF_NULL_ALLOC(watcherState);
watcherState->m_findChangeHandle.reset(FindFirstChangeNotificationW(folderToWatch, isRecursive, static_cast<DWORD>(filter)));
RETURN_LAST_ERROR_IF(!watcherState->m_findChangeHandle);
watcherState->m_threadPoolWait.reset(CreateThreadpoolWait(&folder_watcher_t::callback, watcherState.get(), __nullptr));
RETURN_LAST_ERROR_IF(!watcherState->m_threadPoolWait);
this->reset(watcherState.release()); // no more failures after this, pass ownership
SetThreadpoolWait(this->get()->m_threadPoolWait.get(), this->get()->m_findChangeHandle.get(), __nullptr);
return S_OK;
}
};
typedef unique_any_t<folder_watcher_t<details::unique_storage<details::folder_watcher_state_resource_policy>, err_returncode_policy>> unique_folder_watcher_nothrow;
inline unique_folder_watcher_nothrow make_folder_watcher_nothrow(PCWSTR folderToWatch, bool isRecursive, FolderChangeEvents filter, wistd::function<void()> &&callback) WI_NOEXCEPT
{
unique_folder_watcher_nothrow watcher;
watcher.create(folderToWatch, isRecursive, filter, wistd::move(callback));
return watcher; // caller must test for success using if (watcher)
}
#ifdef WIL_ENABLE_EXCEPTIONS
typedef unique_any_t<folder_watcher_t<details::unique_storage<details::folder_watcher_state_resource_policy>, err_exception_policy>> unique_folder_watcher;
inline unique_folder_watcher make_folder_watcher(PCWSTR folderToWatch, bool isRecursive, FolderChangeEvents filter, wistd::function<void()> &&callback)
{
return unique_folder_watcher(folderToWatch, isRecursive, filter, wistd::move(callback));
}
#endif // WIL_ENABLE_EXCEPTIONS
#pragma endregion
#pragma region Folder Reader
// Example use for throwing:
// auto reader = wil::make_folder_change_reader(folder.Path().c_str(), true, wil::FolderChangeEvents::All,
// [](wil::FolderChangeEvent event, PCWSTR fileName)
// {
// switch (event)
// {
// case wil::FolderChangeEvent::ChangesLost: break;
// case wil::FolderChangeEvent::Added: break;
// case wil::FolderChangeEvent::Removed: break;
// case wil::FolderChangeEvent::Modified: break;
// case wil::FolderChangeEvent::RenamedOldName: break;
// case wil::FolderChangeEvent::RenamedNewName: break;
// });
//
// Example use for non throwing:
// wil::unique_folder_change_reader_nothrow reader;
// THROW_IF_FAILED(reader.create(folder, true, wil::FolderChangeEvents::All,
// [](wil::FolderChangeEvent event, PCWSTR fileName)
// {
// // handle changes
// }));
//
// @cond
namespace details
{
struct folder_change_reader_state
{
folder_change_reader_state(bool isRecursive, FolderChangeEvents filter, wistd::function<void(FolderChangeEvent, PCWSTR)> &&callback)
: m_callback(wistd::move(callback)), m_isRecursive(isRecursive), m_filter(filter)
{
}
~folder_change_reader_state()
{
if (m_tpIo != __nullptr)
{
TP_IO *tpIo = m_tpIo;
// Indicate to the callback function that this object is being torn
// down.
{
auto autoLock = m_cancelLock.lock_exclusive();
m_tpIo = __nullptr;
}
// Cancel IO to terminate the file system monitoring operation.
if (m_folderHandle)
{
CancelIoEx(m_folderHandle.get(), &m_overlapped);
}
// Wait for callbacks to complete.
//
// N.B. This is a blocking call and must not be made within a
// callback or within a lock which is taken inside the
// callback.
WaitForThreadpoolIoCallbacks(tpIo, TRUE);
CloseThreadpoolIo(tpIo);
}
}
HRESULT StartIo()
{
// Unfortunately we have to handle ref-counting of IOs on behalf of the
// thread pool.
StartThreadpoolIo(m_tpIo);
HRESULT hr = ReadDirectoryChangesW(m_folderHandle.get(), m_readBuffer, sizeof(m_readBuffer),
m_isRecursive, static_cast<DWORD>(m_filter), __nullptr, &m_overlapped, __nullptr) ?
S_OK : HRESULT_FROM_WIN32(::GetLastError());
if (FAILED(hr))
{
// This operation does not have the usual semantic of returning
// ERROR_IO_PENDING.
// WI_ASSERT(hr != HRESULT_FROM_WIN32(ERROR_IO_PENDING));
// If the operation failed for whatever reason, ensure the TP
// ref counts are accurate.
CancelThreadpoolIo(m_tpIo);
}
return hr;
}
// void (wil::FolderChangeEvent event, PCWSTR fileName)
wistd::function<void(FolderChangeEvent, PCWSTR)> m_callback;
unique_handle m_folderHandle;
BOOL m_isRecursive = FALSE;
FolderChangeEvents m_filter = FolderChangeEvents::None;
OVERLAPPED m_overlapped{};
TP_IO *m_tpIo = __nullptr;
srwlock m_cancelLock;
unsigned char m_readBuffer[4096]; // Consider alternative buffer sizes. With 512 byte buffer i was not able to observe overflow.
};
inline void delete_folder_change_reader_state(_In_opt_ folder_change_reader_state *storage) { delete storage; }
typedef resource_policy<folder_change_reader_state *, decltype(&details::delete_folder_change_reader_state),
details::delete_folder_change_reader_state, details::pointer_access_none> folder_change_reader_state_resource_policy;
}
/// @endcond
template <typename storage_t, typename err_policy = err_exception_policy>
class folder_change_reader_t : public storage_t
{
public:
// forward all base class constructors...
template <typename... args_t>
explicit folder_change_reader_t(args_t&&... args) WI_NOEXCEPT : storage_t(wistd::forward<args_t>(args)...) {}
// HRESULT or void error handling...
typedef typename err_policy::result result;
// Exception-based constructors
folder_change_reader_t(PCWSTR folderToWatch, bool isRecursive, FolderChangeEvents filter, wistd::function<void(FolderChangeEvent, PCWSTR)> &&callback)
{
static_assert(wistd::is_same<void, result>::value, "this constructor requires exceptions; use the create method");
create(folderToWatch, isRecursive, filter, wistd::move(callback));
}
result create(PCWSTR folderToWatch, bool isRecursive, FolderChangeEvents filter, wistd::function<void(FolderChangeEvent, PCWSTR)> &&callback)
{
return err_policy::HResult(create_common(folderToWatch, isRecursive, filter, wistd::move(callback)));
}
wil::unique_hfile& folder_handle() { return this->get()->m_folderHandle; }
private:
// Factored into a standalone function to support Clang which does not support conversion of stateless lambdas
// to __stdcall
static void __stdcall callback(PTP_CALLBACK_INSTANCE /* Instance */, void *context, void * /*overlapped*/,
ULONG result, ULONG_PTR /* BytesTransferred */, TP_IO * /* Io */)
{
auto readerState = static_cast<details::folder_change_reader_state *>(context);
// WI_ASSERT(overlapped == &readerState->m_overlapped);
if (result == ERROR_SUCCESS)
{
for (auto const& info : create_next_entry_offset_iterator(reinterpret_cast<FILE_NOTIFY_INFORMATION *>(readerState->m_readBuffer)))
{
wchar_t realtiveFileName[MAX_PATH];
StringCchCopyNW(realtiveFileName, ARRAYSIZE(realtiveFileName), info.FileName, info.FileNameLength / sizeof(info.FileName[0]));
readerState->m_callback(static_cast<FolderChangeEvent>(info.Action), realtiveFileName);
}
}
else if (result == ERROR_NOTIFY_ENUM_DIR)
{
readerState->m_callback(FolderChangeEvent::ChangesLost, __nullptr);
}
else
{
// No need to requeue
return;
}
// If the lock is held non-shared or the TP IO is nullptr, this
// structure is being torn down. Otherwise, monitor for further
// changes.
auto autoLock = readerState->m_cancelLock.try_lock_shared();
if (autoLock && readerState->m_tpIo)
{
readerState->StartIo(); // ignoring failure here
}
}
// This function exists to avoid template expansion of this code based on err_policy.
HRESULT create_common(PCWSTR folderToWatch, bool isRecursive, FolderChangeEvents filter, wistd::function<void(FolderChangeEvent, PCWSTR)> &&callback)
{
wistd::unique_ptr<details::folder_change_reader_state> readerState(new(std::nothrow) details::folder_change_reader_state(
isRecursive, filter, wistd::move(callback)));
RETURN_IF_NULL_ALLOC(readerState);
readerState->m_folderHandle.reset(CreateFileW(folderToWatch,
FILE_LIST_DIRECTORY, FILE_SHARE_READ | FILE_SHARE_DELETE | FILE_SHARE_WRITE,
__nullptr, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OVERLAPPED, __nullptr));
RETURN_LAST_ERROR_IF(!readerState->m_folderHandle);
readerState->m_tpIo = CreateThreadpoolIo(readerState->m_folderHandle.get(), &folder_change_reader_t::callback, readerState.get(), __nullptr);
RETURN_LAST_ERROR_IF_NULL(readerState->m_tpIo);
RETURN_IF_FAILED(readerState->StartIo());
this->reset(readerState.release());
return S_OK;
}
};
typedef unique_any_t<folder_change_reader_t<details::unique_storage<details::folder_change_reader_state_resource_policy>, err_returncode_policy>> unique_folder_change_reader_nothrow;
inline unique_folder_change_reader_nothrow make_folder_change_reader_nothrow(PCWSTR folderToWatch, bool isRecursive, FolderChangeEvents filter,
wistd::function<void(FolderChangeEvent, PCWSTR)> &&callback) WI_NOEXCEPT
{
unique_folder_change_reader_nothrow watcher;
watcher.create(folderToWatch, isRecursive, filter, wistd::move(callback));
return watcher; // caller must test for success using if (watcher)
}
#ifdef WIL_ENABLE_EXCEPTIONS
typedef unique_any_t<folder_change_reader_t<details::unique_storage<details::folder_change_reader_state_resource_policy>, err_exception_policy>> unique_folder_change_reader;
inline unique_folder_change_reader make_folder_change_reader(PCWSTR folderToWatch, bool isRecursive, FolderChangeEvents filter,
wistd::function<void(FolderChangeEvent, PCWSTR)> &&callback)
{
return unique_folder_change_reader(folderToWatch, isRecursive, filter, wistd::move(callback));
}
#endif // WIL_ENABLE_EXCEPTIONS
#pragma endregion
//! Dos and VolumeGuid paths are always extended length paths with the \\?\ prefix.
enum class VolumePrefix
{
Dos = VOLUME_NAME_DOS, // Extended Dos Device path form, e.g. \\?\C:\Users\Chris\AppData\Local\Temp\wil8C31.tmp
VolumeGuid = VOLUME_NAME_GUID, // \\?\Volume{588fb606-b95b-4eae-b3cb-1e49861aaf18}\Users\Chris\AppData\Local\Temp\wil8C31.tmp
// The following are special paths which can't be used with Win32 APIs, but are useful in other scenarios.
None = VOLUME_NAME_NONE, // Path without the volume root, e.g. \Users\Chris\AppData\Local\Temp\wil8C31.tmp
NtObjectName = VOLUME_NAME_NT, // Unique name used by Object Manager, e.g. \Device\HarddiskVolume4\Users\Chris\AppData\Local\Temp\wil8C31.tmp
};
enum class PathOptions
{
Normalized = FILE_NAME_NORMALIZED,
Opened = FILE_NAME_OPENED,
};
DEFINE_ENUM_FLAG_OPERATORS(PathOptions);
/** A strongly typed version of the Win32 API GetFinalPathNameByHandleW.
Get the full path name in different forms
Use this instead + VolumePrefix::None instead of GetFileInformationByHandleEx(FileNameInfo) to
get that path form. */
template <typename string_type, size_t stackBufferLength = 256>
HRESULT GetFinalPathNameByHandleW(HANDLE fileHandle, string_type& path,
wil::VolumePrefix volumePrefix = wil::VolumePrefix::Dos, wil::PathOptions options = wil::PathOptions::Normalized)
{
return AdaptFixedSizeToAllocatedResult<string_type, stackBufferLength>(path,
[&](_Out_writes_(valueLength) PWSTR value, size_t valueLength, _Out_ size_t* valueLengthNeededWithNull) -> HRESULT
{
*valueLengthNeededWithNull = ::GetFinalPathNameByHandleW(fileHandle, value, static_cast<DWORD>(valueLength),
static_cast<DWORD>(volumePrefix) | static_cast<DWORD>(options));
RETURN_LAST_ERROR_IF(*valueLengthNeededWithNull == 0);
WI_ASSERT((*value != L'\0') == (*valueLengthNeededWithNull < valueLength));
if (*valueLengthNeededWithNull < valueLength)
{
(*valueLengthNeededWithNull)++; // it fit, account for the null
}
return S_OK;
});
}
#ifdef WIL_ENABLE_EXCEPTIONS
/** A strongly typed version of the Win32 API GetFinalPathNameByHandleW.
Get the full path name in different forms. Use this + VolumePrefix::None
instead of GetFileInformationByHandleEx(FileNameInfo) to get that path form. */
template <typename string_type = wil::unique_cotaskmem_string, size_t stackBufferLength = 256>
string_type GetFinalPathNameByHandleW(HANDLE fileHandle,
wil::VolumePrefix volumePrefix = wil::VolumePrefix::Dos, wil::PathOptions options = wil::PathOptions::Normalized)
{
string_type result;
THROW_IF_FAILED((GetFinalPathNameByHandleW<string_type, stackBufferLength>(fileHandle, result, volumePrefix, options)));
return result;
}
#endif
//! A strongly typed version of the Win32 API of GetCurrentDirectoryW.
//! Return a path in an allocated buffer for handling long paths.
template <typename string_type, size_t stackBufferLength = 256>
HRESULT GetCurrentDirectoryW(string_type& path)
{
return AdaptFixedSizeToAllocatedResult<string_type, stackBufferLength>(path,
[&](_Out_writes_(valueLength) PWSTR value, size_t valueLength, _Out_ size_t* valueLengthNeededWithNull) -> HRESULT
{
*valueLengthNeededWithNull = ::GetCurrentDirectoryW(static_cast<DWORD>(valueLength), value);
RETURN_LAST_ERROR_IF(*valueLengthNeededWithNull == 0);
WI_ASSERT((*value != L'\0') == (*valueLengthNeededWithNull < valueLength));
if (*valueLengthNeededWithNull < valueLength)
{
(*valueLengthNeededWithNull)++; // it fit, account for the null
}
return S_OK;
});
}
#ifdef WIL_ENABLE_EXCEPTIONS
//! A strongly typed version of the Win32 API of GetCurrentDirectoryW.
//! Return a path in an allocated buffer for handling long paths.
template <typename string_type = wil::unique_cotaskmem_string, size_t stackBufferLength = 256>
string_type GetCurrentDirectoryW()
{
string_type result;
THROW_IF_FAILED((GetCurrentDirectoryW<string_type, stackBufferLength>(result)));
return result;
}
#endif
// TODO: add support for these and other similar APIs.
// GetShortPathNameW()
// GetLongPathNameW()
// GetWindowsDirectory()
// GetTempDirectory()
/// @cond
namespace details
{
template <FILE_INFO_BY_HANDLE_CLASS infoClass> struct MapInfoClassToInfoStruct; // failure to map is a usage error caught by the compiler
#define MAP_INFOCLASS_TO_STRUCT(InfoClass, InfoStruct, IsFixed, Extra) \
template <> struct MapInfoClassToInfoStruct<InfoClass> \
{ \
typedef InfoStruct type; \
static bool const isFixed = IsFixed; \
static size_t const extraSize = Extra; \
};
MAP_INFOCLASS_TO_STRUCT(FileBasicInfo, FILE_BASIC_INFO, true, 0);
MAP_INFOCLASS_TO_STRUCT(FileStandardInfo, FILE_STANDARD_INFO, true, 0);
MAP_INFOCLASS_TO_STRUCT(FileNameInfo, FILE_NAME_INFO, false, 32);
MAP_INFOCLASS_TO_STRUCT(FileRenameInfo, FILE_RENAME_INFO, false, 32);
MAP_INFOCLASS_TO_STRUCT(FileDispositionInfo, FILE_DISPOSITION_INFO, true, 0);
MAP_INFOCLASS_TO_STRUCT(FileAllocationInfo, FILE_ALLOCATION_INFO, true, 0);
MAP_INFOCLASS_TO_STRUCT(FileEndOfFileInfo, FILE_END_OF_FILE_INFO, true, 0);
MAP_INFOCLASS_TO_STRUCT(FileStreamInfo, FILE_STREAM_INFO, false, 32);
MAP_INFOCLASS_TO_STRUCT(FileCompressionInfo, FILE_COMPRESSION_INFO, true, 0);
MAP_INFOCLASS_TO_STRUCT(FileAttributeTagInfo, FILE_ATTRIBUTE_TAG_INFO, true, 0);
MAP_INFOCLASS_TO_STRUCT(FileIdBothDirectoryInfo, FILE_ID_BOTH_DIR_INFO, false, 4096);
MAP_INFOCLASS_TO_STRUCT(FileIdBothDirectoryRestartInfo, FILE_ID_BOTH_DIR_INFO, true, 0);
MAP_INFOCLASS_TO_STRUCT(FileIoPriorityHintInfo, FILE_IO_PRIORITY_HINT_INFO, true, 0);
MAP_INFOCLASS_TO_STRUCT(FileRemoteProtocolInfo, FILE_REMOTE_PROTOCOL_INFO, true, 0);
MAP_INFOCLASS_TO_STRUCT(FileFullDirectoryInfo, FILE_FULL_DIR_INFO, false, 4096);
MAP_INFOCLASS_TO_STRUCT(FileFullDirectoryRestartInfo, FILE_FULL_DIR_INFO, true, 0);
#if (_WIN32_WINNT >= _WIN32_WINNT_WIN8)
MAP_INFOCLASS_TO_STRUCT(FileStorageInfo, FILE_STORAGE_INFO, true, 0);
MAP_INFOCLASS_TO_STRUCT(FileAlignmentInfo, FILE_ALIGNMENT_INFO, true, 0);
MAP_INFOCLASS_TO_STRUCT(FileIdInfo, FILE_ID_INFO, true, 0);
MAP_INFOCLASS_TO_STRUCT(FileIdExtdDirectoryInfo, FILE_ID_EXTD_DIR_INFO, false, 4096);
MAP_INFOCLASS_TO_STRUCT(FileIdExtdDirectoryRestartInfo, FILE_ID_EXTD_DIR_INFO, true, 0);
#endif
// Type unsafe version used in the implementation to avoid template bloat.
inline HRESULT GetFileInfo(HANDLE fileHandle, FILE_INFO_BY_HANDLE_CLASS infoClass, size_t allocationSize,
_Outptr_result_maybenull_ void **result)
{
*result = nullptr;
wistd::unique_ptr<char[]> resultHolder(new(std::nothrow) char[allocationSize]);
RETURN_IF_NULL_ALLOC(resultHolder);
for (;;)
{
if (GetFileInformationByHandleEx(fileHandle, infoClass, resultHolder.get(), static_cast<DWORD>(allocationSize)))
{
*result = resultHolder.release();
break;
}
else
{
DWORD const lastError = ::GetLastError();
if (lastError == ERROR_MORE_DATA)
{
allocationSize *= 2;
resultHolder.reset(new(std::nothrow) char[allocationSize]);
RETURN_IF_NULL_ALLOC(resultHolder);
}
else if (lastError == ERROR_NO_MORE_FILES) // for folder enumeration cases
{
break;
}
else if (lastError == ERROR_INVALID_PARAMETER) // operation not supported by file system
{
return HRESULT_FROM_WIN32(lastError);
}
else
{
RETURN_WIN32(lastError);
}
}
}
return S_OK;
}
}
/// @endcond
/** Get file information for a variable sized structure, returns an HRESULT.
~~~
wistd::unique_ptr<FILE_NAME_INFO> fileNameInfo;
RETURN_IF_FAILED(GetFileInfoNoThrow<FileNameInfo>(fileHandle, fileNameInfo));
~~~
*/
template <FILE_INFO_BY_HANDLE_CLASS infoClass, typename wistd::enable_if<!details::MapInfoClassToInfoStruct<infoClass>::isFixed, int>::type = 0>
HRESULT GetFileInfoNoThrow(HANDLE fileHandle, wistd::unique_ptr<typename details::MapInfoClassToInfoStruct<infoClass>::type> &result) WI_NOEXCEPT
{
void *rawResult;
HRESULT hr = details::GetFileInfo(fileHandle, infoClass,
sizeof(typename details::MapInfoClassToInfoStruct<infoClass>::type) + details::MapInfoClassToInfoStruct<infoClass>::extraSize,
&rawResult);
result.reset(static_cast<typename details::MapInfoClassToInfoStruct<infoClass>::type*>(rawResult));
RETURN_HR_IF_EXPECTED(hr, hr == E_INVALIDARG); // operation not supported by file system
RETURN_IF_FAILED(hr);
return S_OK;
}
/** Get file information for a fixed sized structure, returns an HRESULT.
~~~
FILE_BASIC_INFO fileBasicInfo;
RETURN_IF_FAILED(GetFileInfoNoThrow<FileBasicInfo>(fileHandle, &fileBasicInfo));
~~~
*/
template <FILE_INFO_BY_HANDLE_CLASS infoClass, typename wistd::enable_if<details::MapInfoClassToInfoStruct<infoClass>::isFixed, int>::type = 0>
HRESULT GetFileInfoNoThrow(HANDLE fileHandle, _Out_ typename details::MapInfoClassToInfoStruct<infoClass>::type *result) WI_NOEXCEPT
{
const HRESULT hr = GetFileInformationByHandleEx(fileHandle, infoClass, result, sizeof(*result)) ?
S_OK : HRESULT_FROM_WIN32(::GetLastError());
RETURN_HR_IF_EXPECTED(hr, hr == E_INVALIDARG); // operation not supported by file system
RETURN_IF_FAILED(hr);
return S_OK;
}
// Verifies that the given file path is not a hard or a soft link. If the file is present at the path, returns
// a handle to it without delete permissions to block an attacker from swapping the file.
inline HRESULT CreateFileAndEnsureNotLinked(PCWSTR path, wil::unique_hfile& fileHandle)
{
// Open handles to the original path and to the final path and compare each file's information
// to verify they are the same file. If they are different, the file is a soft link.
fileHandle.reset(CreateFileW(path, GENERIC_READ, FILE_SHARE_READ | FILE_SHARE_WRITE, nullptr, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OPEN_REPARSE_POINT, nullptr));
RETURN_LAST_ERROR_IF(!fileHandle);
BY_HANDLE_FILE_INFORMATION fileInfo;
RETURN_IF_WIN32_BOOL_FALSE(GetFileInformationByHandle(fileHandle.get(), &fileInfo));
// Open a handle without the reparse point flag to get the final path in case it is a soft link.
wil::unique_hfile finalPathHandle(CreateFileW(path, 0, 0, nullptr, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, nullptr));
RETURN_LAST_ERROR_IF(!finalPathHandle);
BY_HANDLE_FILE_INFORMATION finalFileInfo;
RETURN_IF_WIN32_BOOL_FALSE(GetFileInformationByHandle(finalPathHandle.get(), &finalFileInfo));
finalPathHandle.reset();
// The low and high indices and volume serial number uniquely identify a file. These must match if they are the same file.
const bool isSoftLink =
((fileInfo.nFileIndexLow != finalFileInfo.nFileIndexLow) ||
(fileInfo.nFileIndexHigh != finalFileInfo.nFileIndexHigh) ||
(fileInfo.dwVolumeSerialNumber != finalFileInfo.dwVolumeSerialNumber));
// Return failure if it is a soft link or a hard link (number of links greater than 1).
RETURN_HR_IF(HRESULT_FROM_WIN32(ERROR_BAD_PATHNAME), (isSoftLink || fileInfo.nNumberOfLinks > 1));
return S_OK;
}
#ifdef _CPPUNWIND
/** Get file information for a fixed sized structure, throws on failure.
~~~
auto fileBasicInfo = GetFileInfo<FileBasicInfo>(fileHandle);
~~~
*/
template <FILE_INFO_BY_HANDLE_CLASS infoClass, typename wistd::enable_if<details::MapInfoClassToInfoStruct<infoClass>::isFixed, int>::type = 0>
typename details::MapInfoClassToInfoStruct<infoClass>::type GetFileInfo(HANDLE fileHandle)
{
typename details::MapInfoClassToInfoStruct<infoClass>::type result;
THROW_IF_FAILED(GetFileInfoNoThrow<infoClass>(fileHandle, &result));
return result;
}
/** Get file information for a variable sized structure, throws on failure.
~~~
auto fileBasicInfo = GetFileInfo<FileNameInfo>(fileHandle);
~~~
*/
template <FILE_INFO_BY_HANDLE_CLASS infoClass, typename wistd::enable_if<!details::MapInfoClassToInfoStruct<infoClass>::isFixed, int>::type = 0>
wistd::unique_ptr<typename details::MapInfoClassToInfoStruct<infoClass>::type> GetFileInfo(HANDLE fileHandle)
{
wistd::unique_ptr<typename details::MapInfoClassToInfoStruct<infoClass>::type> result;
THROW_IF_FAILED(GetFileInfoNoThrow<infoClass>(fileHandle, result));
return result;
}
#endif // _CPPUNWIND
#endif // WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP) && (_WIN32_WINNT >= _WIN32_WINNT_WIN7)
}
#endif // __WIL_FILESYSTEM_INCLUDED
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