// Copyright 2010-2021, Google Inc.
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// met:
//
//     * Redistributions of source code must retain the above copyright
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#include "base/file_util.h"

#ifdef OS_WIN
#include <KtmW32.h>
#include <Windows.h>
#else
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#endif  // OS_WIN

#include "base/file_stream.h"
#include "base/logging.h"
#include "base/mmap.h"
#include "base/mutex.h"
#include "base/scoped_handle.h"
#include "base/singleton.h"
#include "base/util.h"
#include "base/win_util.h"

namespace {

#ifdef OS_WIN
const char kFileDelimiter = '\\';
#else
const char kFileDelimiter = '/';
#endif  // OS_WIN

}  // namespace

// Ad-hoc workadound against macro problem on Windows.
// On Windows, following macros, defined when you include <Windows.h>,
// should be removed here because they affects the method name definition of
// Util class.
// TODO(yukawa): Use different method name if applicable.
#ifdef CreateDirectory
#undef CreateDirectory
#endif  // CreateDirectory
#ifdef RemoveDirectory
#undef RemoveDirectory
#endif  // RemoveDirectory
#ifdef CopyFile
#undef CopyFile
#endif  // CopyFile

namespace mozc {
namespace {
class FileUtilImpl : public FileUtilInterface {
 public:
  FileUtilImpl() = default;
  ~FileUtilImpl() override = default;

  bool CreateDirectory(const std::string &path) const override;
  bool RemoveDirectory(const std::string &dirname) const override;
  bool Unlink(const std::string &filename) const override;
  bool FileExists(const std::string &filename) const override;
  bool DirectoryExists(const std::string &dirname) const override;
  bool CopyFile(const std::string &from, const std::string &to) const override;
  bool IsEqualFile(const std::string &filename1,
                   const std::string &filename2) const override;
  bool AtomicRename(const std::string &from,
                    const std::string &to) const override;
  bool GetModificationTime(const std::string &filename,
                           FileTimeStamp *modified_at) const override;
};

using FileUtilSingleton = SingletonMockable<FileUtilInterface, FileUtilImpl>;

}  // namespace

#ifdef OS_WIN
namespace {

// Some high-level file APIs such as MoveFileEx simply fail if the target file
// has some special attribute like read-only. This method tries to strip system,
// hidden, and read-only attributes from |filename|.
// This function does nothing if |filename| does not exist.
void StripWritePreventingAttributesIfExists(const std::string &filename) {
  if (!FileUtil::FileExists(filename)) {
    return;
  }
  std::wstring wide_filename;
  Util::UTF8ToWide(filename, &wide_filename);
  const DWORD kDropAttributes =
      FILE_ATTRIBUTE_SYSTEM | FILE_ATTRIBUTE_HIDDEN | FILE_ATTRIBUTE_READONLY;
  const DWORD attributes = ::GetFileAttributesW(wide_filename.c_str());
  if (attributes & kDropAttributes) {
    ::SetFileAttributesW(wide_filename.c_str(), attributes & ~kDropAttributes);
  }
}

}  // namespace
#endif  // OS_WIN

bool FileUtil::CreateDirectory(const std::string &path) {
  return FileUtilSingleton::Get()->CreateDirectory(path);
}

bool FileUtilImpl::CreateDirectory(const std::string &path) const {
#if defined(OS_WIN)
  std::wstring wide;
  return (Util::UTF8ToWide(path, &wide) > 0 &&
          ::CreateDirectoryW(wide.c_str(), nullptr) != 0);
#else   // !OS_WIN
  return ::mkdir(path.c_str(), 0700) == 0;
#endif  // OS_WIN
}

bool FileUtil::RemoveDirectory(const std::string &dirname) {
  return FileUtilSingleton::Get()->RemoveDirectory(dirname);
}

bool FileUtilImpl::RemoveDirectory(const std::string &dirname) const {
#ifdef OS_WIN
  std::wstring wide;
  return (Util::UTF8ToWide(dirname, &wide) > 0 &&
          ::RemoveDirectoryW(wide.c_str()) != 0);
#else   // !OS_WIN
  return ::rmdir(dirname.c_str()) == 0;
#endif  // OS_WIN
}

bool FileUtil::Unlink(const std::string &filename) {
  return FileUtilSingleton::Get()->Unlink(filename);
}

bool FileUtilImpl::Unlink(const std::string &filename) const {
#ifdef OS_WIN
  StripWritePreventingAttributesIfExists(filename);
  std::wstring wide;
  return (Util::UTF8ToWide(filename, &wide) > 0 &&
          ::DeleteFileW(wide.c_str()) != 0);
#else   // !OS_WIN
  return ::unlink(filename.c_str()) == 0;
#endif  // OS_WIN
}

bool FileUtil::FileExists(const std::string &filename) {
  return FileUtilSingleton::Get()->FileExists(filename);
}

bool FileUtilImpl::FileExists(const std::string &filename) const {
#ifdef OS_WIN
  std::wstring wide;
  return (Util::UTF8ToWide(filename, &wide) > 0 &&
          ::GetFileAttributesW(wide.c_str()) != -1);
#else   // !OS_WIN
  struct stat s;
  return ::stat(filename.c_str(), &s) == 0;
#endif  // OS_WIN
}

bool FileUtil::DirectoryExists(const std::string &dirname) {
  return FileUtilSingleton::Get()->DirectoryExists(dirname);
}

bool FileUtilImpl::DirectoryExists(const std::string &dirname) const {
#ifdef OS_WIN
  std::wstring wide;
  if (Util::UTF8ToWide(dirname, &wide) <= 0) {
    return false;
  }

  const DWORD attribute = ::GetFileAttributesW(wide.c_str());
  return ((attribute != -1) && (attribute & FILE_ATTRIBUTE_DIRECTORY));
#else   // !OS_WIN
  struct stat s;
  return (::stat(dirname.c_str(), &s) == 0 && S_ISDIR(s.st_mode));
#endif  // OS_WIN
}

#ifdef OS_WIN
namespace {

bool TransactionalMoveFile(const std::wstring &from, const std::wstring &to) {
  const DWORD kTimeout = 5000;  // 5 sec.
  ScopedHandle handle(
      ::CreateTransaction(nullptr, 0, 0, 0, 0, kTimeout, nullptr));
  const DWORD create_transaction_error = ::GetLastError();
  if (handle.get() == 0) {
    LOG(ERROR) << "CreateTransaction failed: " << create_transaction_error;
    return false;
  }

  WIN32_FILE_ATTRIBUTE_DATA file_attribute_data = {};
  if (!::GetFileAttributesTransactedW(from.c_str(), GetFileExInfoStandard,
                                      &file_attribute_data, handle.get())) {
    const DWORD get_file_attributes_error = ::GetLastError();
    LOG(ERROR) << "GetFileAttributesTransactedW failed: "
               << get_file_attributes_error;
    return false;
  }

  if (!::MoveFileTransactedW(from.c_str(), to.c_str(), nullptr, nullptr,
                             MOVEFILE_COPY_ALLOWED | MOVEFILE_REPLACE_EXISTING,
                             handle.get())) {
    const DWORD move_file_transacted_error = ::GetLastError();
    LOG(ERROR) << "MoveFileTransactedW failed: " << move_file_transacted_error;
    return false;
  }

  if (!::SetFileAttributesTransactedW(
          to.c_str(), file_attribute_data.dwFileAttributes, handle.get())) {
    const DWORD set_file_attributes_error = ::GetLastError();
    LOG(ERROR) << "SetFileAttributesTransactedW failed: "
               << set_file_attributes_error;
    return false;
  }

  if (!::CommitTransaction(handle.get())) {
    const DWORD commit_transaction_error = ::GetLastError();
    LOG(ERROR) << "CommitTransaction failed: " << commit_transaction_error;
    return false;
  }

  return true;
}

}  // namespace

bool FileUtil::HideFile(const std::string &filename) {
  return HideFileWithExtraAttributes(filename, 0);
}

bool FileUtil::HideFileWithExtraAttributes(const std::string &filename,
                                           DWORD extra_attributes) {
  if (!FileUtil::FileExists(filename)) {
    LOG(WARNING) << "File not exists. " << filename;
    return false;
  }

  std::wstring wfilename;
  Util::UTF8ToWide(filename, &wfilename);

  const DWORD original_attributes = ::GetFileAttributesW(wfilename.c_str());
  const auto result = ::SetFileAttributesW(
      wfilename.c_str(), (FILE_ATTRIBUTE_HIDDEN | FILE_ATTRIBUTE_SYSTEM |
                          FILE_ATTRIBUTE_NOT_CONTENT_INDEXED |
                          original_attributes | extra_attributes) &
                             ~FILE_ATTRIBUTE_NORMAL);
  return result != 0;
}
#endif  // OS_WIN

bool FileUtil::CopyFile(const std::string &from, const std::string &to) {
  return FileUtilSingleton::Get()->CopyFile(from, to);
}

bool FileUtilImpl::CopyFile(const std::string &from,
                            const std::string &to) const {
  InputFileStream ifs(from.c_str(), std::ios::binary);
  if (!ifs) {
    LOG(ERROR) << "Can't open input file. " << from;
    return false;
  }

#ifdef OS_WIN
  std::wstring wto;
  Util::UTF8ToWide(to, &wto);
  StripWritePreventingAttributesIfExists(to);
#endif  // OS_WIN

  OutputFileStream ofs(to.c_str(), std::ios::binary | std::ios::trunc);
  if (!ofs) {
    LOG(ERROR) << "Can't open output file. " << to;
    return false;
  }

  // TODO(taku): we have to check disk quota in advance.
  if (!(ofs << ifs.rdbuf())) {
    LOG(ERROR) << "Can't write data.";
    return false;
  }
  ifs.close();
  ofs.close();

#ifdef OS_WIN
  std::wstring wfrom;
  Util::UTF8ToWide(from, &wfrom);
  ::SetFileAttributesW(wto.c_str(), ::GetFileAttributesW(wfrom.c_str()));
#endif  // OS_WIN

  return true;
}

bool FileUtil::IsEqualFile(const std::string &filename1,
                           const std::string &filename2) {
  return FileUtilSingleton::Get()->IsEqualFile(filename1, filename2);
}

bool FileUtilImpl::IsEqualFile(const std::string &filename1,
                               const std::string &filename2) const {
  Mmap mmap1, mmap2;

  if (!mmap1.Open(filename1.c_str(), "r")) {
    LOG(ERROR) << "Cannot open: " << filename1;
    return false;
  }

  if (!mmap2.Open(filename2.c_str(), "r")) {
    LOG(ERROR) << "Cannot open: " << filename2;
    return false;
  }

  if (mmap1.size() != mmap2.size()) {
    return false;
  }

  return memcmp(mmap1.begin(), mmap2.begin(), mmap1.size()) == 0;
}

bool FileUtil::AtomicRename(const std::string &from, const std::string &to) {
  return FileUtilSingleton::Get()->AtomicRename(from, to);
}

bool FileUtilImpl::AtomicRename(const std::string &from,
                                const std::string &to) const {
#ifdef OS_WIN
  std::wstring fromw, tow;
  Util::UTF8ToWide(from, &fromw);
  Util::UTF8ToWide(to, &tow);

  if (TransactionalMoveFile(fromw, tow)) {
    return true;
  }

  const DWORD original_attributes = ::GetFileAttributesW(fromw.c_str());
  StripWritePreventingAttributesIfExists(to);
  if (!::MoveFileExW(fromw.c_str(), tow.c_str(),
                     MOVEFILE_COPY_ALLOWED | MOVEFILE_REPLACE_EXISTING)) {
    const DWORD move_file_ex_error = ::GetLastError();
    LOG(ERROR) << "MoveFileEx failed: " << move_file_ex_error;
    return false;
  }
  ::SetFileAttributesW(tow.c_str(), original_attributes);

  return true;
#else   // !OS_WIN
  // Mac OSX: use rename(2), but rename(2) on Mac OSX
  // is not properly implemented, atomic rename is POSIX spec though.
  // http://www.weirdnet.nl/apple/rename.html
  return rename(from.c_str(), to.c_str()) == 0;
#endif  // OS_WIN
}

std::string FileUtil::JoinPath(
    const std::vector<absl::string_view> &components) {
  std::string output;
  JoinPath(components, &output);
  return output;
}

void FileUtil::JoinPath(const std::vector<absl::string_view> &components,
                        std::string *output) {
  output->clear();
  for (size_t i = 0; i < components.size(); ++i) {
    if (components[i].empty()) {
      continue;
    }
    if (!output->empty() && output->back() != kFileDelimiter) {
      output->append(1, kFileDelimiter);
    }
    output->append(components[i].data(), components[i].size());
  }
}

// TODO(taku): what happens if filename == '/foo/bar/../bar/..
std::string FileUtil::Dirname(const std::string &filename) {
  const std::string::size_type p = filename.find_last_of(kFileDelimiter);
  if (p == std::string::npos) {
    return "";
  }
  return filename.substr(0, p);
}

std::string FileUtil::Basename(const std::string &filename) {
  const std::string::size_type p = filename.find_last_of(kFileDelimiter);
  if (p == std::string::npos) {
    return filename;
  }
  return filename.substr(p + 1, filename.size() - p);
}

std::string FileUtil::NormalizeDirectorySeparator(const std::string &path) {
#ifdef OS_WIN
  const char kFileDelimiterForUnix = '/';
  const char kFileDelimiterForWindows = '\\';
  std::string normalized;
  Util::StringReplace(path, std::string(1, kFileDelimiterForUnix),
                      std::string(1, kFileDelimiterForWindows), true,
                      &normalized);
  return normalized;
#else
  return path;
#endif  // OS_WIN
}

bool FileUtil::GetModificationTime(const std::string &filename,
                                   FileTimeStamp *modified_at) {
  return FileUtilSingleton::Get()->GetModificationTime(filename, modified_at);
}

bool FileUtilImpl::GetModificationTime(const std::string &filename,
                                       FileTimeStamp *modified_at) const {
#if defined(OS_WIN)
  std::wstring wide;
  if (!Util::UTF8ToWide(filename, &wide)) {
    return false;
  }
  WIN32_FILE_ATTRIBUTE_DATA info = {};
  if (!::GetFileAttributesEx(wide.c_str(), GetFileExInfoStandard, &info)) {
    const auto last_error = ::GetLastError();
    LOG(ERROR) << "GetFileAttributesEx(" << filename
               << ") failed. error=" << last_error;
    return false;
  }
  *modified_at =
      (static_cast<uint64>(info.ftLastWriteTime.dwHighDateTime) << 32) +
      info.ftLastWriteTime.dwLowDateTime;
  return true;
#else   // !OS_WIN
  struct stat stat_info;
  if (::stat(filename.c_str(), &stat_info)) {
    return false;
  }
  *modified_at = stat_info.st_mtime;
  return true;
#endif  // OS_WIN
}

void FileUtil::SetMockForUnitTest(FileUtilInterface *mock) {
  FileUtilSingleton::SetMock(mock);
}

}  // namespace mozc
