/**
 * @file winfsp/winfsp.hpp
 * WinFsp C++ Layer.
 *
 * @copyright 2015-2022 Bill Zissimopoulos
 */
/*
 * This file is part of WinFsp.
 *
 * You can redistribute it and/or modify it under the terms of the GNU
 * General Public License version 3 as published by the Free Software
 * Foundation.
 *
 * Licensees holding a valid commercial license may use this software
 * in accordance with the commercial license agreement provided in
 * conjunction with the software.  The terms and conditions of any such
 * commercial license agreement shall govern, supersede, and render
 * ineffective any application of the GPLv3 license to this software,
 * notwithstanding of any reference thereto in the software or
 * associated repository.
 */

#ifndef WINFSP_WINFSP_HPP_INCLUDED
#define WINFSP_WINFSP_HPP_INCLUDED

#ifndef __cplusplus
#error this header requires a C++ compiler
#endif

#include <winfsp/winfsp.h>

#define FSP_CPP_EXCEPTION_GUARD(...)                                           \
  try {                                                                        \
    __VA_ARGS__                                                                \
  } catch (...) {                                                              \
    return self->ExceptionHandler();                                           \
  }
#define FSP_CPP_EXCEPTION_GUARD_VOID(...)                                      \
  try {                                                                        \
    __VA_ARGS__                                                                \
  } catch (...) {                                                              \
    self->ExceptionHandler();                                                  \
    return;                                                                    \
  }

namespace Fsp {

inline NTSTATUS Initialize() {
  static NTSTATUS LoadResult = FspLoad(0);
  return LoadResult;
}

class FileSystemBase {
public:
  typedef FSP_FSCTL_VOLUME_INFO VolumeInfo;
  typedef FSP_FSCTL_FILE_INFO FileInfo;
  typedef FSP_FSCTL_OPEN_FILE_INFO OpenFileInfo;
  typedef FSP_FSCTL_DIR_INFO DirInfo;
  typedef FSP_FSCTL_STREAM_INFO StreamInfo;
  enum CleanupFlags {
    CleanupDelete = FspCleanupDelete,
    CleanupSetAllocationSize = FspCleanupSetAllocationSize,
    CleanupSetArchiveBit = FspCleanupSetArchiveBit,
    CleanupSetLastAccessTime = FspCleanupSetLastAccessTime,
    CleanupSetLastWriteTime = FspCleanupSetLastWriteTime,
    CleanupSetChangeTime = FspCleanupSetChangeTime,
  };

public:
  FileSystemBase() {}
  virtual ~FileSystemBase() {}

  /* operations */
  virtual NTSTATUS ExceptionHandler() { return STATUS_UNEXPECTED_IO_ERROR; }
  virtual NTSTATUS Init(PVOID Host) { return STATUS_SUCCESS; }
  virtual NTSTATUS Mounted(PVOID Host) { return STATUS_SUCCESS; }
  virtual VOID Unmounted(PVOID Host) {}
  virtual NTSTATUS GetVolumeInfo(VolumeInfo *VolumeInfo) {
    return STATUS_INVALID_DEVICE_REQUEST;
  }
  virtual NTSTATUS SetVolumeLabel_(PWSTR VolumeLabel, VolumeInfo *VolumeInfo) {
    return STATUS_INVALID_DEVICE_REQUEST;
  }
  virtual NTSTATUS
  GetSecurityByName(PWSTR FileName,
                    PUINT32 PFileAttributes /* or ReparsePointIndex */,
                    PSECURITY_DESCRIPTOR SecurityDescriptor,
                    SIZE_T *PSecurityDescriptorSize) {
    return STATUS_INVALID_DEVICE_REQUEST;
  }
  virtual NTSTATUS Create(PWSTR FileName, UINT32 CreateOptions,
                          UINT32 GrantedAccess, UINT32 FileAttributes,
                          PSECURITY_DESCRIPTOR SecurityDescriptor,
                          UINT64 AllocationSize, PVOID *PFileNode,
                          PVOID *PFileDesc, OpenFileInfo *OpenFileInfo) {
    return STATUS_INVALID_DEVICE_REQUEST;
  }
  virtual NTSTATUS Open(PWSTR FileName, UINT32 CreateOptions,
                        UINT32 GrantedAccess, PVOID *PFileNode,
                        PVOID *PFileDesc, OpenFileInfo *OpenFileInfo) {
    return STATUS_INVALID_DEVICE_REQUEST;
  }
  virtual NTSTATUS Overwrite(PVOID FileNode, PVOID FileDesc,
                             UINT32 FileAttributes,
                             BOOLEAN ReplaceFileAttributes,
                             UINT64 AllocationSize, FileInfo *FileInfo) {
    return STATUS_INVALID_DEVICE_REQUEST;
  }
  virtual VOID Cleanup(PVOID FileNode, PVOID FileDesc, PWSTR FileName,
                       ULONG Flags) {}
  virtual VOID Close(PVOID FileNode, PVOID FileDesc) {}
  virtual NTSTATUS Read(PVOID FileNode, PVOID FileDesc, PVOID Buffer,
                        UINT64 Offset, ULONG Length, PULONG PBytesTransferred) {
    return STATUS_INVALID_DEVICE_REQUEST;
  }
  virtual NTSTATUS Write(PVOID FileNode, PVOID FileDesc, PVOID Buffer,
                         UINT64 Offset, ULONG Length, BOOLEAN WriteToEndOfFile,
                         BOOLEAN ConstrainedIo, PULONG PBytesTransferred,
                         FileInfo *FileInfo) {
    return STATUS_INVALID_DEVICE_REQUEST;
  }
  virtual NTSTATUS Flush(PVOID FileNode, PVOID FileDesc, FileInfo *FileInfo) {
    return STATUS_INVALID_DEVICE_REQUEST;
  }
  virtual NTSTATUS GetFileInfo(PVOID FileNode, PVOID FileDesc,
                               FileInfo *FileInfo) {
    return STATUS_INVALID_DEVICE_REQUEST;
  }
  virtual NTSTATUS SetBasicInfo(PVOID FileNode, PVOID FileDesc,
                                UINT32 FileAttributes, UINT64 CreationTime,
                                UINT64 LastAccessTime, UINT64 LastWriteTime,
                                UINT64 ChangeTime, FileInfo *FileInfo) {
    return STATUS_INVALID_DEVICE_REQUEST;
  }
  virtual NTSTATUS SetFileSize(PVOID FileNode, PVOID FileDesc, UINT64 NewSize,
                               BOOLEAN SetAllocationSize, FileInfo *FileInfo) {
    return STATUS_INVALID_DEVICE_REQUEST;
  }
  virtual NTSTATUS CanDelete(PVOID FileNode, PVOID FileDesc, PWSTR FileName) {
    return STATUS_INVALID_DEVICE_REQUEST;
  }
  virtual NTSTATUS Rename(PVOID FileNode, PVOID FileDesc, PWSTR FileName,
                          PWSTR NewFileName, BOOLEAN ReplaceIfExists) {
    return STATUS_INVALID_DEVICE_REQUEST;
  }
  virtual NTSTATUS GetSecurity(PVOID FileNode, PVOID FileDesc,
                               PSECURITY_DESCRIPTOR SecurityDescriptor,
                               SIZE_T *PSecurityDescriptorSize) {
    return STATUS_INVALID_DEVICE_REQUEST;
  }
  virtual NTSTATUS SetSecurity(PVOID FileNode, PVOID FileDesc,
                               SECURITY_INFORMATION SecurityInformation,
                               PSECURITY_DESCRIPTOR ModificationDescriptor) {
    return STATUS_INVALID_DEVICE_REQUEST;
  }
  virtual NTSTATUS ReadDirectory(PVOID FileNode, PVOID FileDesc, PWSTR Pattern,
                                 PWSTR Marker, PVOID Buffer, ULONG Length,
                                 PULONG PBytesTransferred) {
    return SeekableReadDirectory(FileNode, FileDesc, Pattern, Marker, Buffer,
                                 Length, PBytesTransferred);
  }
  virtual NTSTATUS ReadDirectoryEntry(PVOID FileNode, PVOID FileDesc,
                                      PWSTR Pattern, PWSTR Marker,
                                      PVOID *PContext, DirInfo *DirInfo) {
    return STATUS_INVALID_DEVICE_REQUEST;
  }
  virtual NTSTATUS ResolveReparsePoints(PWSTR FileName,
                                        UINT32 ReparsePointIndex,
                                        BOOLEAN ResolveLastPathComponent,
                                        PIO_STATUS_BLOCK PIoStatus,
                                        PVOID Buffer, PSIZE_T PSize) {
    return FspFileSystemResolveReparsePoints(
        0, GetReparsePointByName, this, FileName, ReparsePointIndex,
        ResolveLastPathComponent, PIoStatus, Buffer, PSize);
  }
  virtual NTSTATUS GetReparsePointByName(PWSTR FileName, BOOLEAN IsDirectory,
                                         PVOID Buffer, PSIZE_T PSize) {
    return STATUS_INVALID_DEVICE_REQUEST;
  }
  virtual NTSTATUS GetReparsePoint(PVOID FileNode, PVOID FileDesc,
                                   PWSTR FileName, PVOID Buffer,
                                   PSIZE_T PSize) {
    return STATUS_INVALID_DEVICE_REQUEST;
  }
  virtual NTSTATUS SetReparsePoint(PVOID FileNode, PVOID FileDesc,
                                   PWSTR FileName, PVOID Buffer, SIZE_T Size) {
    return STATUS_INVALID_DEVICE_REQUEST;
  }
  virtual NTSTATUS DeleteReparsePoint(PVOID FileNode, PVOID FileDesc,
                                      PWSTR FileName, PVOID Buffer,
                                      SIZE_T Size) {
    return STATUS_INVALID_DEVICE_REQUEST;
  }
  virtual NTSTATUS GetStreamInfo(PVOID FileNode, PVOID FileDesc, PVOID Buffer,
                                 ULONG Length, PULONG PBytesTransferred) {
    return STATUS_INVALID_DEVICE_REQUEST;
  }

  /* helpers */
  static NTSTATUS NtStatusFromWin32(DWORD Error) {
    return FspNtStatusFromWin32(Error);
  }
  static DWORD Win32FromNtStatus(NTSTATUS Status) {
    return FspWin32FromNtStatus(Status);
  }
  static VOID DeleteDirectoryBuffer(PVOID *PDirBuffer) {
    FspFileSystemDeleteDirectoryBuffer(PDirBuffer);
  }
  NTSTATUS SeekableReadDirectory(PVOID FileNode, PVOID FileDesc, PWSTR Pattern,
                                 PWSTR Marker, PVOID Buffer, ULONG Length,
                                 PULONG PBytesTransferred) {
    PVOID Context = 0;
    union {
      UINT8 B[FIELD_OFFSET(FileSystemBase::DirInfo, FileNameBuf) +
              MAX_PATH * sizeof(WCHAR)];
      FileSystemBase::DirInfo D;
    } DirInfoBuf;
    FileSystemBase::DirInfo *DirInfo = &DirInfoBuf.D;
    NTSTATUS Result = STATUS_SUCCESS;
    *PBytesTransferred = 0;
    for (;;) {
      Result = ReadDirectoryEntry(FileNode, FileDesc, Pattern, Marker, &Context,
                                  DirInfo);
      if (STATUS_NO_MORE_FILES == Result) {
        Result = STATUS_SUCCESS;
        break;
      }
      if (!NT_SUCCESS(Result))
        break;
      if (!FspFileSystemAddDirInfo(DirInfo, Buffer, Length, PBytesTransferred))
        break;
    }
    if (!NT_SUCCESS(Result))
      return Result;
    return STATUS_SUCCESS;
  }
  NTSTATUS BufferedReadDirectory(PVOID *PDirBuffer, PVOID FileNode,
                                 PVOID FileDesc, PWSTR Pattern, PWSTR Marker,
                                 PVOID Buffer, ULONG Length,
                                 PULONG PBytesTransferred) {
    PVOID Context = 0;
    union {
      UINT8 B[FIELD_OFFSET(FileSystemBase::DirInfo, FileNameBuf) +
              MAX_PATH * sizeof(WCHAR)];
      FileSystemBase::DirInfo D;
    } DirInfoBuf;
    FileSystemBase::DirInfo *DirInfo = &DirInfoBuf.D;
    NTSTATUS Result = STATUS_SUCCESS;
    *PBytesTransferred = 0;
    if (FspFileSystemAcquireDirectoryBuffer(PDirBuffer, 0 == Marker, &Result)) {
      try {
        for (;;) {
          Result = ReadDirectoryEntry(FileNode, FileDesc, Pattern, Marker,
                                      &Context, DirInfo);
          if (STATUS_NO_MORE_FILES == Result) {
            Result = STATUS_SUCCESS;
            break;
          }
          if (!NT_SUCCESS(Result))
            break;
          if (!FspFileSystemFillDirectoryBuffer(PDirBuffer, DirInfo, &Result))
            break;
        }
      } catch (...) {
        FspFileSystemReleaseDirectoryBuffer(PDirBuffer);
        throw;
      }
      FspFileSystemReleaseDirectoryBuffer(PDirBuffer);
    }
    if (!NT_SUCCESS(Result))
      return Result;
    FspFileSystemReadDirectoryBuffer(PDirBuffer, Marker, Buffer, Length,
                                     PBytesTransferred);
    return STATUS_SUCCESS;
  }
  BOOLEAN FindReparsePoint(PWSTR FileName, PUINT32 PReparsePointIndex) {
    return FspFileSystemFindReparsePoint(0, GetReparsePointByName, this,
                                         FileName, PReparsePointIndex);
  }
  static NTSTATUS CanReplaceReparsePoint(PVOID CurrentReparseData,
                                         SIZE_T CurrentReparseDataSize,
                                         PVOID ReplaceReparseData,
                                         SIZE_T ReplaceReparseDataSize) {
    return FspFileSystemCanReplaceReparsePoint(
        CurrentReparseData, CurrentReparseDataSize, ReplaceReparseData,
        ReplaceReparseDataSize);
  }
  static BOOLEAN AddStreamInfo(StreamInfo *StreamInfo, PVOID Buffer,
                               ULONG Length, PULONG PBytesTransferred) {
    return FspFileSystemAddStreamInfo(StreamInfo, Buffer, Length,
                                      PBytesTransferred);
  }

private:
  static NTSTATUS GetReparsePointByName(FSP_FILE_SYSTEM *FileSystem,
                                        PVOID Context, PWSTR FileName,
                                        BOOLEAN IsDirectory, PVOID Buffer,
                                        PSIZE_T PSize) {
    FileSystemBase *self = (FileSystemBase *)Context;
    FSP_CPP_EXCEPTION_GUARD(return self->GetReparsePointByName(
        FileName, IsDirectory, Buffer, PSize);)
  }

private:
  /* disallow copy and assignment */
  FileSystemBase(const FileSystemBase &);
  FileSystemBase &operator=(const FileSystemBase &);
};

class FileSystemHost {
public:
  /* ctor/dtor */
  FileSystemHost(FileSystemBase &FileSystem)
      : _VolumeParams(), _FileSystemPtr(0), _FileSystem(&FileSystem) {
    Initialize();
    _VolumeParams.UmFileContextIsFullContext = 1;
  }
  virtual ~FileSystemHost() {
    if (0 != _FileSystemPtr)
      FspFileSystemDelete(_FileSystemPtr);
  }

  /* properties */
  UINT16 SectorSize() { return _VolumeParams.SectorSize; }
  VOID SetSectorSize(UINT16 SectorSize) {
    _VolumeParams.SectorSize = SectorSize;
  }
  UINT16 SectorsPerAllocationUnit() {
    return _VolumeParams.SectorsPerAllocationUnit;
  }
  VOID SetSectorsPerAllocationUnit(UINT16 SectorsPerAllocationUnit) {
    _VolumeParams.SectorsPerAllocationUnit = SectorsPerAllocationUnit;
  }
  UINT16 MaxComponentLength() { return _VolumeParams.MaxComponentLength; }
  VOID SetMaxComponentLength(UINT16 MaxComponentLength) {
    _VolumeParams.MaxComponentLength = MaxComponentLength;
  }
  UINT64 VolumeCreationTime() { return _VolumeParams.VolumeCreationTime; }
  VOID SetVolumeCreationTime(UINT64 VolumeCreationTime) {
    _VolumeParams.VolumeCreationTime = VolumeCreationTime;
  }
  UINT32 VolumeSerialNumber() { return _VolumeParams.VolumeSerialNumber; }
  VOID SetVolumeSerialNumber(UINT32 VolumeSerialNumber) {
    _VolumeParams.VolumeSerialNumber = VolumeSerialNumber;
  }
  UINT32 FileInfoTimeout() { return _VolumeParams.FileInfoTimeout; }
  VOID SetFileInfoTimeout(UINT32 FileInfoTimeout) {
    _VolumeParams.FileInfoTimeout = FileInfoTimeout;
  }
  BOOLEAN CaseSensitiveSearch() { return _VolumeParams.CaseSensitiveSearch; }
  VOID SetCaseSensitiveSearch(BOOLEAN CaseSensitiveSearch) {
    _VolumeParams.CaseSensitiveSearch = !!CaseSensitiveSearch;
  }
  BOOLEAN CasePreservedNames() { return _VolumeParams.CasePreservedNames; }
  VOID SetCasePreservedNames(BOOLEAN CasePreservedNames) {
    _VolumeParams.CasePreservedNames = !!CasePreservedNames;
  }
  BOOLEAN UnicodeOnDisk() { return _VolumeParams.UnicodeOnDisk; }
  VOID SetUnicodeOnDisk(BOOLEAN UnicodeOnDisk) {
    _VolumeParams.UnicodeOnDisk = !!UnicodeOnDisk;
  }
  BOOLEAN PersistentAcls() { return _VolumeParams.PersistentAcls; }
  VOID SetPersistentAcls(BOOLEAN PersistentAcls) {
    _VolumeParams.PersistentAcls = !!PersistentAcls;
  }
  BOOLEAN ReparsePoints() { return _VolumeParams.ReparsePoints; }
  VOID SetReparsePoints(BOOLEAN ReparsePoints) {
    _VolumeParams.ReparsePoints = !!ReparsePoints;
  }
  BOOLEAN ReparsePointsAccessCheck() {
    return _VolumeParams.ReparsePointsAccessCheck;
  }
  VOID SetReparsePointsAccessCheck(BOOLEAN ReparsePointsAccessCheck) {
    _VolumeParams.ReparsePointsAccessCheck = !!ReparsePointsAccessCheck;
  }
  BOOLEAN NamedStreams() { return _VolumeParams.NamedStreams; }
  VOID SetNamedStreams(BOOLEAN NamedStreams) {
    _VolumeParams.NamedStreams = !!NamedStreams;
  }
  BOOLEAN PostCleanupWhenModifiedOnly() {
    return _VolumeParams.PostCleanupWhenModifiedOnly;
  }
  VOID SetPostCleanupWhenModifiedOnly(BOOLEAN PostCleanupWhenModifiedOnly) {
    _VolumeParams.PostCleanupWhenModifiedOnly = !!PostCleanupWhenModifiedOnly;
  }
  BOOLEAN PassQueryDirectoryPattern() {
    return _VolumeParams.PassQueryDirectoryPattern;
  }
  VOID SetPassQueryDirectoryPattern(BOOLEAN PassQueryDirectoryPattern) {
    _VolumeParams.PassQueryDirectoryPattern = !!PassQueryDirectoryPattern;
  }
  BOOLEAN FlushAndPurgeOnCleanup() {
    return _VolumeParams.FlushAndPurgeOnCleanup;
  }
  VOID SetFlushAndPurgeOnCleanup(BOOLEAN FlushAndPurgeOnCleanup) {
    _VolumeParams.FlushAndPurgeOnCleanup = !!FlushAndPurgeOnCleanup;
  }
  PWSTR Prefix() { return _VolumeParams.Prefix; }
  VOID SetPrefix(PWSTR Prefix) {
    int Size = lstrlenW(Prefix) * sizeof(WCHAR);
    if (Size > sizeof _VolumeParams.Prefix - sizeof(WCHAR))
      Size = sizeof _VolumeParams.Prefix - sizeof(WCHAR);
    RtlCopyMemory(_VolumeParams.Prefix, Prefix, Size);
    _VolumeParams.Prefix[Size / sizeof(WCHAR)] = L'\0';
  }
  PWSTR FileSystemName() { return _VolumeParams.FileSystemName; }
  VOID SetFileSystemName(PWSTR FileSystemName) {
    int Size = lstrlenW(FileSystemName) * sizeof(WCHAR);
    if (Size > sizeof _VolumeParams.FileSystemName - sizeof(WCHAR))
      Size = sizeof _VolumeParams.FileSystemName - sizeof(WCHAR);
    RtlCopyMemory(_VolumeParams.FileSystemName, FileSystemName, Size);
    _VolumeParams.FileSystemName[Size / sizeof(WCHAR)] = L'\0';
  }

  /* control */
  NTSTATUS Preflight(PWSTR MountPoint) {
    return FspFileSystemPreflight((PWSTR)(_VolumeParams.Prefix[0]
                                              ? L"" FSP_FSCTL_NET_DEVICE_NAME
                                              : L"" FSP_FSCTL_DISK_DEVICE_NAME),
                                  MountPoint);
  }
  NTSTATUS Mount(PWSTR MountPoint, PSECURITY_DESCRIPTOR SecurityDescriptor = 0,
                 BOOLEAN Synchronized = FALSE, UINT32 DebugLog = 0) {
    NTSTATUS Result;
    try {
      Result = _FileSystem->Init(this);
    } catch (...) {
      Result = _FileSystem->ExceptionHandler();
    }
    if (!NT_SUCCESS(Result))
      return Result;
    Result = FspFileSystemCreate((PWSTR)(_VolumeParams.Prefix[0]
                                             ? L"" FSP_FSCTL_NET_DEVICE_NAME
                                             : L"" FSP_FSCTL_DISK_DEVICE_NAME),
                                 &_VolumeParams, Interface(), &_FileSystemPtr);
    if (!NT_SUCCESS(Result))
      return Result;
    _FileSystemPtr->UserContext = _FileSystem;
    FspFileSystemSetOperationGuardStrategy(
        _FileSystemPtr, Synchronized
                            ? FSP_FILE_SYSTEM_OPERATION_GUARD_STRATEGY_COARSE
                            : FSP_FILE_SYSTEM_OPERATION_GUARD_STRATEGY_FINE);
    FspFileSystemSetDebugLog(_FileSystemPtr, DebugLog);
    Result = FspFileSystemSetMountPointEx(_FileSystemPtr, MountPoint,
                                          SecurityDescriptor);
    if (NT_SUCCESS(Result)) {
      try {
        Result = _FileSystem->Mounted(this);
      } catch (...) {
        Result = _FileSystem->ExceptionHandler();
      }
      if (NT_SUCCESS(Result)) {
        Result = FspFileSystemStartDispatcher(_FileSystemPtr, 0);
        if (!NT_SUCCESS(Result))
          try {
            _FileSystem->Unmounted(this);
          } catch (...) {
            _FileSystem->ExceptionHandler();
          }
      }
    }
    if (!NT_SUCCESS(Result)) {
      FspFileSystemDelete(_FileSystemPtr);
      _FileSystemPtr = 0;
    }
    return Result;
  }
  VOID Unmount() {
    FspFileSystemStopDispatcher(_FileSystemPtr);
    try {
      _FileSystem->Unmounted(this);
    } catch (...) {
      _FileSystem->ExceptionHandler();
    }
    _FileSystemPtr->UserContext = 0;
    FspFileSystemDelete(_FileSystemPtr);
    _FileSystemPtr = 0;
  }
  PWSTR MountPoint() {
    return 0 != _FileSystemPtr ? FspFileSystemMountPoint(_FileSystemPtr) : 0;
  }
  FSP_FILE_SYSTEM *FileSystemHandle() { return _FileSystemPtr; }
  FileSystemBase &FileSystem() { return *_FileSystem; }
  static NTSTATUS SetDebugLogFile(PWSTR FileName) {
    HANDLE Handle;
    if ('-' == FileName[0] && '\0' == FileName[1])
      Handle = GetStdHandle(STD_ERROR_HANDLE);
    else
      Handle = CreateFileW(FileName, FILE_APPEND_DATA,
                           FILE_SHARE_READ | FILE_SHARE_WRITE, 0, OPEN_ALWAYS,
                           FILE_ATTRIBUTE_NORMAL, 0);
    if (INVALID_HANDLE_VALUE == Handle)
      return FspNtStatusFromWin32(GetLastError());
    FspDebugLogSetHandle(Handle);
    return STATUS_SUCCESS;
  }

private:
  /* FSP_FILE_SYSTEM_INTERFACE */
  static NTSTATUS GetVolumeInfo(FSP_FILE_SYSTEM *FileSystem0,
                                FSP_FSCTL_VOLUME_INFO *VolumeInfo) {
    FileSystemBase *self = (FileSystemBase *)FileSystem0->UserContext;
    FSP_CPP_EXCEPTION_GUARD(return self->GetVolumeInfo(VolumeInfo);)
  }
  static NTSTATUS SetVolumeLabel_(FSP_FILE_SYSTEM *FileSystem0,
                                  PWSTR VolumeLabel,
                                  FSP_FSCTL_VOLUME_INFO *VolumeInfo) {
    FileSystemBase *self = (FileSystemBase *)FileSystem0->UserContext;
    FSP_CPP_EXCEPTION_GUARD(
        return self->SetVolumeLabel_(VolumeLabel, VolumeInfo);)
  }
  static NTSTATUS
  GetSecurityByName(FSP_FILE_SYSTEM *FileSystem0, PWSTR FileName,
                    PUINT32 PFileAttributes /* or ReparsePointIndex */,
                    PSECURITY_DESCRIPTOR SecurityDescriptor,
                    SIZE_T *PSecurityDescriptorSize) {
    FileSystemBase *self = (FileSystemBase *)FileSystem0->UserContext;
    FSP_CPP_EXCEPTION_GUARD(return self->GetSecurityByName(
        FileName, PFileAttributes, SecurityDescriptor,
        PSecurityDescriptorSize);)
  }
  static NTSTATUS Create(FSP_FILE_SYSTEM *FileSystem0, PWSTR FileName,
                         UINT32 CreateOptions, UINT32 GrantedAccess,
                         UINT32 FileAttributes,
                         PSECURITY_DESCRIPTOR SecurityDescriptor,
                         UINT64 AllocationSize, PVOID *FullContext,
                         FSP_FSCTL_FILE_INFO *FileInfo) {
    FileSystemBase *self = (FileSystemBase *)FileSystem0->UserContext;
    PVOID FileNode, FileDesc;
    NTSTATUS Result;
    FSP_CPP_EXCEPTION_GUARD(
        Result =
            self->Create(FileName, CreateOptions, GrantedAccess, FileAttributes,
                         SecurityDescriptor, AllocationSize, &FileNode,
                         &FileDesc, FspFileSystemGetOpenFileInfo(FileInfo));)
    ((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)->UserContext =
        (UINT64)(UINT_PTR)FileNode;
    ((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)->UserContext2 =
        (UINT64)(UINT_PTR)FileDesc;
    return Result;
  }
  static NTSTATUS Open(FSP_FILE_SYSTEM *FileSystem0, PWSTR FileName,
                       UINT32 CreateOptions, UINT32 GrantedAccess,
                       PVOID *FullContext, FSP_FSCTL_FILE_INFO *FileInfo) {
    FileSystemBase *self = (FileSystemBase *)FileSystem0->UserContext;
    PVOID FileNode, FileDesc;
    NTSTATUS Result;
    FSP_CPP_EXCEPTION_GUARD(
        Result = self->Open(FileName, CreateOptions, GrantedAccess, &FileNode,
                            &FileDesc, FspFileSystemGetOpenFileInfo(FileInfo));)
    ((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)->UserContext =
        (UINT64)(UINT_PTR)FileNode;
    ((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)->UserContext2 =
        (UINT64)(UINT_PTR)FileDesc;
    return Result;
  }
  static NTSTATUS Overwrite(FSP_FILE_SYSTEM *FileSystem0, PVOID FullContext,
                            UINT32 FileAttributes,
                            BOOLEAN ReplaceFileAttributes,
                            UINT64 AllocationSize,
                            FSP_FSCTL_FILE_INFO *FileInfo) {
    FileSystemBase *self = (FileSystemBase *)FileSystem0->UserContext;
    FSP_CPP_EXCEPTION_GUARD(return self->Overwrite(
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext,
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext2,
        FileAttributes, ReplaceFileAttributes, AllocationSize, FileInfo);)
  }
  static VOID Cleanup(FSP_FILE_SYSTEM *FileSystem0, PVOID FullContext,
                      PWSTR FileName, ULONG Flags) {
    FileSystemBase *self = (FileSystemBase *)FileSystem0->UserContext;
    FSP_CPP_EXCEPTION_GUARD_VOID(return self->Cleanup(
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext,
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext2,
        FileName, Flags);)
  }
  static VOID Close(FSP_FILE_SYSTEM *FileSystem0, PVOID FullContext) {
    FileSystemBase *self = (FileSystemBase *)FileSystem0->UserContext;
    FSP_CPP_EXCEPTION_GUARD_VOID(return self->Close(
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext,
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext2);)
  }
  static NTSTATUS Read(FSP_FILE_SYSTEM *FileSystem0, PVOID FullContext,
                       PVOID Buffer, UINT64 Offset, ULONG Length,
                       PULONG PBytesTransferred) {
    FileSystemBase *self = (FileSystemBase *)FileSystem0->UserContext;
    FSP_CPP_EXCEPTION_GUARD(return self->Read(
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext,
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext2,
        Buffer, Offset, Length, PBytesTransferred);)
  }
  static NTSTATUS Write(FSP_FILE_SYSTEM *FileSystem0, PVOID FullContext,
                        PVOID Buffer, UINT64 Offset, ULONG Length,
                        BOOLEAN WriteToEndOfFile, BOOLEAN ConstrainedIo,
                        PULONG PBytesTransferred,
                        FSP_FSCTL_FILE_INFO *FileInfo) {
    FileSystemBase *self = (FileSystemBase *)FileSystem0->UserContext;
    FSP_CPP_EXCEPTION_GUARD(return self->Write(
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext,
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext2,
        Buffer, Offset, Length, WriteToEndOfFile, ConstrainedIo,
        PBytesTransferred, FileInfo);)
  }
  static NTSTATUS Flush(FSP_FILE_SYSTEM *FileSystem0, PVOID FullContext,
                        FSP_FSCTL_FILE_INFO *FileInfo) {
    FileSystemBase *self = (FileSystemBase *)FileSystem0->UserContext;
    FSP_CPP_EXCEPTION_GUARD(return self->Flush(
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext,
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext2,
        FileInfo);)
  }
  static NTSTATUS GetFileInfo(FSP_FILE_SYSTEM *FileSystem0, PVOID FullContext,
                              FSP_FSCTL_FILE_INFO *FileInfo) {
    FileSystemBase *self = (FileSystemBase *)FileSystem0->UserContext;
    FSP_CPP_EXCEPTION_GUARD(return self->GetFileInfo(
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext,
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext2,
        FileInfo);)
  }
  static NTSTATUS SetBasicInfo(FSP_FILE_SYSTEM *FileSystem0, PVOID FullContext,
                               UINT32 FileAttributes, UINT64 CreationTime,
                               UINT64 LastAccessTime, UINT64 LastWriteTime,
                               UINT64 ChangeTime,
                               FSP_FSCTL_FILE_INFO *FileInfo) {
    FileSystemBase *self = (FileSystemBase *)FileSystem0->UserContext;
    FSP_CPP_EXCEPTION_GUARD(return self->SetBasicInfo(
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext,
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext2,
        FileAttributes, CreationTime, LastAccessTime, LastWriteTime, ChangeTime,
        FileInfo);)
  }
  static NTSTATUS SetFileSize(FSP_FILE_SYSTEM *FileSystem0, PVOID FullContext,
                              UINT64 NewSize, BOOLEAN SetAllocationSize,
                              FSP_FSCTL_FILE_INFO *FileInfo) {
    FileSystemBase *self = (FileSystemBase *)FileSystem0->UserContext;
    FSP_CPP_EXCEPTION_GUARD(return self->SetFileSize(
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext,
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext2,
        NewSize, SetAllocationSize, FileInfo);)
  }
  static NTSTATUS CanDelete(FSP_FILE_SYSTEM *FileSystem0, PVOID FullContext,
                            PWSTR FileName) {
    FileSystemBase *self = (FileSystemBase *)FileSystem0->UserContext;
    FSP_CPP_EXCEPTION_GUARD(return self->CanDelete(
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext,
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext2,
        FileName);)
  }
  static NTSTATUS Rename(FSP_FILE_SYSTEM *FileSystem0, PVOID FullContext,
                         PWSTR FileName, PWSTR NewFileName,
                         BOOLEAN ReplaceIfExists) {
    FileSystemBase *self = (FileSystemBase *)FileSystem0->UserContext;
    FSP_CPP_EXCEPTION_GUARD(return self->Rename(
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext,
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext2,
        FileName, NewFileName, ReplaceIfExists);)
  }
  static NTSTATUS GetSecurity(FSP_FILE_SYSTEM *FileSystem0, PVOID FullContext,
                              PSECURITY_DESCRIPTOR SecurityDescriptor,
                              SIZE_T *PSecurityDescriptorSize) {
    FileSystemBase *self = (FileSystemBase *)FileSystem0->UserContext;
    FSP_CPP_EXCEPTION_GUARD(return self->GetSecurity(
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext,
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext2,
        SecurityDescriptor, PSecurityDescriptorSize);)
  }
  static NTSTATUS SetSecurity(FSP_FILE_SYSTEM *FileSystem0, PVOID FullContext,
                              SECURITY_INFORMATION SecurityInformation,
                              PSECURITY_DESCRIPTOR ModificationDescriptor) {
    FileSystemBase *self = (FileSystemBase *)FileSystem0->UserContext;
    FSP_CPP_EXCEPTION_GUARD(return self->SetSecurity(
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext,
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext2,
        SecurityInformation, ModificationDescriptor);)
  }
  static NTSTATUS ReadDirectory(FSP_FILE_SYSTEM *FileSystem0, PVOID FullContext,
                                PWSTR Pattern, PWSTR Marker, PVOID Buffer,
                                ULONG Length, PULONG PBytesTransferred) {
    FileSystemBase *self = (FileSystemBase *)FileSystem0->UserContext;
    FSP_CPP_EXCEPTION_GUARD(return self->ReadDirectory(
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext,
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext2,
        Pattern, Marker, Buffer, Length, PBytesTransferred);)
  }
  static NTSTATUS ResolveReparsePoints(FSP_FILE_SYSTEM *FileSystem0,
                                       PWSTR FileName, UINT32 ReparsePointIndex,
                                       BOOLEAN ResolveLastPathComponent,
                                       PIO_STATUS_BLOCK PIoStatus, PVOID Buffer,
                                       PSIZE_T PSize) {
    FileSystemBase *self = (FileSystemBase *)FileSystem0->UserContext;
    FSP_CPP_EXCEPTION_GUARD(return self->ResolveReparsePoints(
        FileName, ReparsePointIndex, ResolveLastPathComponent, PIoStatus,
        Buffer, PSize);)
  }
  static NTSTATUS GetReparsePoint(FSP_FILE_SYSTEM *FileSystem0,
                                  PVOID FullContext, PWSTR FileName,
                                  PVOID Buffer, PSIZE_T PSize) {
    FileSystemBase *self = (FileSystemBase *)FileSystem0->UserContext;
    FSP_CPP_EXCEPTION_GUARD(return self->GetReparsePoint(
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext,
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext2,
        FileName, Buffer, PSize);)
  }
  static NTSTATUS SetReparsePoint(FSP_FILE_SYSTEM *FileSystem0,
                                  PVOID FullContext, PWSTR FileName,
                                  PVOID Buffer, SIZE_T Size) {
    FileSystemBase *self = (FileSystemBase *)FileSystem0->UserContext;
    FSP_CPP_EXCEPTION_GUARD(return self->SetReparsePoint(
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext,
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext2,
        FileName, Buffer, Size);)
  }
  static NTSTATUS DeleteReparsePoint(FSP_FILE_SYSTEM *FileSystem0,
                                     PVOID FullContext, PWSTR FileName,
                                     PVOID Buffer, SIZE_T Size) {
    FileSystemBase *self = (FileSystemBase *)FileSystem0->UserContext;
    FSP_CPP_EXCEPTION_GUARD(return self->DeleteReparsePoint(
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext,
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext2,
        FileName, Buffer, Size);)
  }
  static NTSTATUS GetStreamInfo(FSP_FILE_SYSTEM *FileSystem0, PVOID FullContext,
                                PVOID Buffer, ULONG Length,
                                PULONG PBytesTransferred) {
    FileSystemBase *self = (FileSystemBase *)FileSystem0->UserContext;
    FSP_CPP_EXCEPTION_GUARD(return self->GetStreamInfo(
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext,
        (PVOID)(UINT_PTR)((FSP_FSCTL_TRANSACT_FULL_CONTEXT *)FullContext)
            ->UserContext2,
        Buffer, Length, PBytesTransferred);)
  }
  static FSP_FILE_SYSTEM_INTERFACE *Interface() {
    static FSP_FILE_SYSTEM_INTERFACE _Interface = {
        GetVolumeInfo,
        SetVolumeLabel_,
        GetSecurityByName,
        Create,
        Open,
        Overwrite,
        Cleanup,
        Close,
        Read,
        Write,
        Flush,
        GetFileInfo,
        SetBasicInfo,
        SetFileSize,
        CanDelete,
        Rename,
        GetSecurity,
        SetSecurity,
        ReadDirectory,
        ResolveReparsePoints,
        GetReparsePoint,
        SetReparsePoint,
        DeleteReparsePoint,
        GetStreamInfo,
    };
    return &_Interface;
  }

private:
  /* disallow copy and assignment */
  FileSystemHost(const FileSystemHost &);
  FileSystemHost &operator=(const FileSystemHost &);

private:
  FSP_FSCTL_VOLUME_PARAMS _VolumeParams;
  FSP_FILE_SYSTEM *_FileSystemPtr;
  FileSystemBase *_FileSystem;
};

class Service {
public:
  /* ctor/dtor */
  Service(PWSTR ServiceName) : _Service(0) {
    Initialize();
    FspServiceCreate(ServiceName, OnStart, OnStop, 0, &_Service);
    if (0 != _Service)
      _Service->UserContext = this;
  }
  virtual ~Service() {
    if (0 != _Service)
      FspServiceDelete(_Service);
  }

  /* control */
  ULONG Run() {
    if (0 == _Service) {
      FspServiceLog(EVENTLOG_ERROR_TYPE,
                    L"The service cannot be created (Status=%lx).",
                    STATUS_INSUFFICIENT_RESOURCES);
      return FspWin32FromNtStatus(STATUS_INSUFFICIENT_RESOURCES);
    }
    FspServiceAllowConsoleMode(_Service);
    NTSTATUS Result = FspServiceLoop(_Service);
    ULONG ExitCode = FspServiceGetExitCode(_Service);
    if (!NT_SUCCESS(Result)) {
      FspServiceLog(EVENTLOG_ERROR_TYPE,
                    L"The service has failed to run (Status=%lx).", Result);
      return FspWin32FromNtStatus(Result);
    }
    return ExitCode;
  }
  VOID Stop() {
    if (0 == _Service)
      return;
    FspServiceStop(_Service);
  }
  VOID RequestTime(ULONG Time) {
    if (0 == _Service)
      return;
    FspServiceRequestTime(_Service, Time);
  }
  ULONG GetExitCode() {
    return 0 != _Service ? FspServiceGetExitCode(_Service)
                         : ERROR_NO_SYSTEM_RESOURCES;
  }
  VOID SetExitCode(ULONG ExitCode) {
    if (0 == _Service)
      return;
    FspServiceSetExitCode(_Service, ExitCode);
  }
  FSP_SERVICE *ServiceHandle() { return _Service; }
  static VOID Log(ULONG Type, PWSTR Format, ...) {
    va_list ap;
    va_start(ap, Format);
    FspServiceLogV(Type, Format, ap);
    va_end(ap);
  }
  static VOID LogV(ULONG Type, PWSTR Format, va_list ap) {
    FspServiceLogV(Type, Format, ap);
  }

protected:
  /* start/stop */
  virtual NTSTATUS ExceptionHandler() {
    return 0xE06D7363 /*STATUS_CPP_EH_EXCEPTION*/;
  }
  virtual NTSTATUS OnStart(ULONG Argc, PWSTR *Argv) { return STATUS_SUCCESS; }
  virtual NTSTATUS OnStop() { return STATUS_SUCCESS; }

private:
  /* callbacks */
  static NTSTATUS OnStart(FSP_SERVICE *Service0, ULONG Argc, PWSTR *Argv) {
    Service *self = (Service *)Service0->UserContext;
    FSP_CPP_EXCEPTION_GUARD(return self->OnStart(Argc, Argv);)
  }
  static NTSTATUS OnStop(FSP_SERVICE *Service0) {
    Service *self = (Service *)Service0->UserContext;
    FSP_CPP_EXCEPTION_GUARD(return self->OnStop();)
  }

private:
  /* disallow copy and assignment */
  Service(const Service &);
  Service &operator=(const Service &);

private:
  FSP_SERVICE *_Service;
};

} // namespace Fsp

#undef FSP_CPP_EXCEPTION_GUARD
#undef FSP_CPP_EXCEPTION_GUARD_VOID

#endif