// Copyright (c) 2012 The Chromium Authors. All rights reserved.

// Use of this source code is governed by a BSD-style license that can be

// found in the LICENSE file.

#include "butil/files/file.h"

#include <errno.h>

#include <fcntl.h>

#include <sys/stat.h>

#include <unistd.h>

#include "butil/files/file_path.h"

#include "butil/logging.h"

#include "butil/posix/eintr_wrapper.h"

#include "butil/strings/utf_string_conversions.h"

#include "butil/threading/thread_restrictions.h"

#if defined(OS_ANDROID)

#include "butil/os_compat_android.h"

#endif

namespace butil {

// Make sure our Whence mappings match the system headers.

COMPILE_ASSERT(File::FROM_BEGIN   == SEEK_SET &&

               File::FROM_CURRENT == SEEK_CUR &&

               File::FROM_END     == SEEK_END, whence_matches_system);

namespace {

#if defined(OS_BSD) || defined(OS_MACOSX) || defined(OS_NACL)

static int CallFstat(int fd, stat_wrapper_t *sb) {

  butil::ThreadRestrictions::AssertIOAllowed();

  return fstat(fd, sb);

}

#else

static int CallFstat(int fd, stat_wrapper_t *sb) {

  butil::ThreadRestrictions::AssertIOAllowed();

  return fstat64(fd, sb);

}

#endif

// NaCl doesn't provide the following system calls, so either simulate them or

// wrap them in order to minimize the number of #ifdef's in this file.

#if !defined(OS_NACL)

static bool IsOpenAppend(PlatformFile file) {

  return (fcntl(file, F_GETFL) & O_APPEND) != 0;

}

static int CallFtruncate(PlatformFile file, int64_t length) {

  return HANDLE_EINTR(ftruncate(file, length));

}

static int CallFsync(PlatformFile file) {

  return HANDLE_EINTR(fsync(file));

}

static int CallFutimes(PlatformFile file, const struct timeval times[2]) {

#ifdef __USE_XOPEN2K8

  // futimens should be available, but futimes might not be

  // http://pubs.opengroup.org/onlinepubs/9699919799/

  timespec ts_times[2];

  ts_times[0].tv_sec  = times[0].tv_sec;

  ts_times[0].tv_nsec = times[0].tv_usec * 1000;

  ts_times[1].tv_sec  = times[1].tv_sec;

  ts_times[1].tv_nsec = times[1].tv_usec * 1000;

  return futimens(file, ts_times);

#else

  return futimes(file, times);

#endif

}

static File::Error CallFctnlFlock(PlatformFile file, bool do_lock) {

  struct flock lock;

  lock.l_type = F_WRLCK;

  lock.l_whence = SEEK_SET;

  lock.l_start = 0;

  lock.l_len = 0;  // Lock entire file.

  if (HANDLE_EINTR(fcntl(file, do_lock ? F_SETLK : F_UNLCK, &lock)) == -1)

    return File::OSErrorToFileError(errno);

  return File::FILE_OK;

}

#else  // defined(OS_NACL)

static bool IsOpenAppend(PlatformFile file) {

  // NaCl doesn't implement fcntl. Since NaCl's write conforms to the POSIX

  // standard and always appends if the file is opened with O_APPEND, just

  // return false here.

  return false;

}

static int CallFtruncate(PlatformFile file, int64_t length) {

  NOTIMPLEMENTED();  // NaCl doesn't implement ftruncate.

  return 0;

}

static int CallFsync(PlatformFile file) {

  NOTIMPLEMENTED();  // NaCl doesn't implement fsync.

  return 0;

}

static int CallFutimes(PlatformFile file, const struct timeval times[2]) {

  NOTIMPLEMENTED();  // NaCl doesn't implement futimes.

  return 0;

}

static File::Error CallFctnlFlock(PlatformFile file, bool do_lock) {

  NOTIMPLEMENTED();  // NaCl doesn't implement flock struct.

  return File::FILE_ERROR_INVALID_OPERATION;

}

#endif  // defined(OS_NACL)

}  // namespace

void File::Info::FromStat(const stat_wrapper_t& stat_info) {

  is_directory = S_ISDIR(stat_info.st_mode);

  is_symbolic_link = S_ISLNK(stat_info.st_mode);

  size = stat_info.st_size;

#if defined(OS_LINUX)

  time_t last_modified_sec = stat_info.st_mtim.tv_sec;

  int64_t last_modified_nsec = stat_info.st_mtim.tv_nsec;

  time_t last_accessed_sec = stat_info.st_atim.tv_sec;

  int64_t last_accessed_nsec = stat_info.st_atim.tv_nsec;

  time_t creation_time_sec = stat_info.st_ctim.tv_sec;

  int64_t creation_time_nsec = stat_info.st_ctim.tv_nsec;

#elif defined(OS_ANDROID)

  time_t last_modified_sec = stat_info.st_mtime;

  int64_t last_modified_nsec = stat_info.st_mtime_nsec;

  time_t last_accessed_sec = stat_info.st_atime;

  int64_t last_accessed_nsec = stat_info.st_atime_nsec;

  time_t creation_time_sec = stat_info.st_ctime;

  int64_t creation_time_nsec = stat_info.st_ctime_nsec;

#elif defined(OS_MACOSX) || defined(OS_IOS) || defined(OS_BSD)

  time_t last_modified_sec = stat_info.st_mtimespec.tv_sec;

  int64_t last_modified_nsec = stat_info.st_mtimespec.tv_nsec;

  time_t last_accessed_sec = stat_info.st_atimespec.tv_sec;

  int64_t last_accessed_nsec = stat_info.st_atimespec.tv_nsec;

  time_t creation_time_sec = stat_info.st_ctimespec.tv_sec;

  int64_t creation_time_nsec = stat_info.st_ctimespec.tv_nsec;

#else

  time_t last_modified_sec = stat_info.st_mtime;

  int64_t last_modified_nsec = 0;

  time_t last_accessed_sec = stat_info.st_atime;

  int64_t last_accessed_nsec = 0;

  time_t creation_time_sec = stat_info.st_ctime;

  int64_t creation_time_nsec = 0;

#endif

  last_modified =

      Time::FromTimeT(last_modified_sec) +

      TimeDelta::FromMicroseconds(last_modified_nsec /

                                  Time::kNanosecondsPerMicrosecond);

  last_accessed =

      Time::FromTimeT(last_accessed_sec) +

      TimeDelta::FromMicroseconds(last_accessed_nsec /

                                  Time::kNanosecondsPerMicrosecond);

  creation_time =

      Time::FromTimeT(creation_time_sec) +

      TimeDelta::FromMicroseconds(creation_time_nsec /

                                  Time::kNanosecondsPerMicrosecond);

}

// NaCl doesn't implement system calls to open files directly.

#if !defined(OS_NACL)

// TODO(erikkay): does it make sense to support FLAG_EXCLUSIVE_* here?

void File::InitializeUnsafe(const FilePath& name, uint32_t flags) {

  butil::ThreadRestrictions::AssertIOAllowed();

  DCHECK(!IsValid());

  int open_flags = 0;

  if (flags & FLAG_CREATE)

    open_flags = O_CREAT | O_EXCL;

  created_ = false;

  if (flags & FLAG_CREATE_ALWAYS) {

    DCHECK(!open_flags);

    DCHECK(flags & FLAG_WRITE);

    open_flags = O_CREAT | O_TRUNC;

  }

  if (flags & FLAG_OPEN_TRUNCATED) {

    DCHECK(!open_flags);

    DCHECK(flags & FLAG_WRITE);

    open_flags = O_TRUNC;

  }

  if (!open_flags && !(flags & FLAG_OPEN) && !(flags & FLAG_OPEN_ALWAYS)) {

    NOTREACHED();

    errno = EOPNOTSUPP;

    error_details_ = FILE_ERROR_FAILED;

    return;

  }

  if (flags & FLAG_WRITE && flags & FLAG_READ) {

    open_flags |= O_RDWR;

  } else if (flags & FLAG_WRITE) {

    open_flags |= O_WRONLY;

  } else if (!(flags & FLAG_READ) &&

             !(flags & FLAG_WRITE_ATTRIBUTES) &&

             !(flags & FLAG_APPEND) &&

             !(flags & FLAG_OPEN_ALWAYS)) {

    NOTREACHED();

  }

  if (flags & FLAG_TERMINAL_DEVICE)

    open_flags |= O_NOCTTY | O_NDELAY;

  if (flags & FLAG_APPEND && flags & FLAG_READ)

    open_flags |= O_APPEND | O_RDWR;

  else if (flags & FLAG_APPEND)

    open_flags |= O_APPEND | O_WRONLY;

  COMPILE_ASSERT(O_RDONLY == 0, O_RDONLY_must_equal_zero);

  int mode = S_IRUSR | S_IWUSR;

#if defined(OS_CHROMEOS)

  mode |= S_IRGRP | S_IROTH;

#endif

  int descriptor = HANDLE_EINTR(open(name.value().c_str(), open_flags, mode));

  if (flags & FLAG_OPEN_ALWAYS) {

    if (descriptor < 0) {

      open_flags |= O_CREAT;

      if (flags & FLAG_EXCLUSIVE_READ || flags & FLAG_EXCLUSIVE_WRITE)

        open_flags |= O_EXCL;   // together with O_CREAT implies O_NOFOLLOW

      descriptor = HANDLE_EINTR(open(name.value().c_str(), open_flags, mode));

      if (descriptor >= 0)

        created_ = true;

    }

  }

  if (descriptor < 0) {

    error_details_ = File::OSErrorToFileError(errno);

    return;

  }

  if (flags & (FLAG_CREATE_ALWAYS | FLAG_CREATE))

    created_ = true;

  if (flags & FLAG_DELETE_ON_CLOSE)

    unlink(name.value().c_str());

  async_ = ((flags & FLAG_ASYNC) == FLAG_ASYNC);

  error_details_ = FILE_OK;

  file_.reset(descriptor);

}

#endif  // !defined(OS_NACL)

bool File::IsValid() const {

  return file_.is_valid();

}

PlatformFile File::GetPlatformFile() const {

  return file_.get();

}

PlatformFile File::TakePlatformFile() {

  return file_.release();

}

void File::Close() {

  if (!IsValid())

    return;

  butil::ThreadRestrictions::AssertIOAllowed();

  file_.reset();

}

int64_t File::Seek(Whence whence, int64_t offset) {

  butil::ThreadRestrictions::AssertIOAllowed();

  DCHECK(IsValid());

#if defined(OS_ANDROID)

  COMPILE_ASSERT(sizeof(int64_t) == sizeof(off64_t), off64_t_64_bit);

  return lseek64(file_.get(), static_cast<off64_t>(offset),

                 static_cast<int>(whence));

#else

  COMPILE_ASSERT(sizeof(int64_t) == sizeof(off_t), off_t_64_bit);

  return lseek(file_.get(), static_cast<off_t>(offset),

               static_cast<int>(whence));

#endif

}

int File::Read(int64_t offset, char* data, int size) {

  butil::ThreadRestrictions::AssertIOAllowed();

  DCHECK(IsValid());

  if (size < 0)

    return -1;

  int bytes_read = 0;

  int rv;

  do {

    rv = HANDLE_EINTR(pread(file_.get(), data + bytes_read,

                            size - bytes_read, offset + bytes_read));

    if (rv <= 0)

      break;

    bytes_read += rv;

  } while (bytes_read < size);

  return bytes_read ? bytes_read : rv;

}

int File::ReadAtCurrentPos(char* data, int size) {

  butil::ThreadRestrictions::AssertIOAllowed();

  DCHECK(IsValid());

  if (size < 0)

    return -1;

  int bytes_read = 0;

  int rv;

  do {

    rv = HANDLE_EINTR(read(file_.get(), data + bytes_read, size - bytes_read));

    if (rv <= 0)

      break;

    bytes_read += rv;

  } while (bytes_read < size);

  return bytes_read ? bytes_read : rv;

}

int File::ReadNoBestEffort(int64_t offset, char* data, int size) {

  butil::ThreadRestrictions::AssertIOAllowed();

  DCHECK(IsValid());

  return HANDLE_EINTR(pread(file_.get(), data, size, offset));

}

int File::ReadAtCurrentPosNoBestEffort(char* data, int size) {

  butil::ThreadRestrictions::AssertIOAllowed();

  DCHECK(IsValid());

  if (size < 0)

    return -1;

  return HANDLE_EINTR(read(file_.get(), data, size));

}

int File::Write(int64_t offset, const char* data, int size) {

  butil::ThreadRestrictions::AssertIOAllowed();

  if (IsOpenAppend(file_.get()))

    return WriteAtCurrentPos(data, size);

  DCHECK(IsValid());

  if (size < 0)

    return -1;

  int bytes_written = 0;

  int rv;

  do {

    rv = HANDLE_EINTR(pwrite(file_.get(), data + bytes_written,

                             size - bytes_written, offset + bytes_written));

    if (rv <= 0)

      break;

    bytes_written += rv;

  } while (bytes_written < size);

  return bytes_written ? bytes_written : rv;

}

int File::WriteAtCurrentPos(const char* data, int size) {

  butil::ThreadRestrictions::AssertIOAllowed();

  DCHECK(IsValid());

  if (size < 0)

    return -1;

  int bytes_written = 0;

  int rv;

  do {

    rv = HANDLE_EINTR(write(file_.get(), data + bytes_written,

                            size - bytes_written));

    if (rv <= 0)

      break;

    bytes_written += rv;

  } while (bytes_written < size);

  return bytes_written ? bytes_written : rv;

}

int File::WriteAtCurrentPosNoBestEffort(const char* data, int size) {

  butil::ThreadRestrictions::AssertIOAllowed();

  DCHECK(IsValid());

  if (size < 0)

    return -1;

  return HANDLE_EINTR(write(file_.get(), data, size));

}

int64_t File::GetLength() {

  DCHECK(IsValid());

  stat_wrapper_t file_info;

  if (CallFstat(file_.get(), &file_info))

    return false;

  return file_info.st_size;

}

bool File::SetLength(int64_t length) {

  butil::ThreadRestrictions::AssertIOAllowed();

  DCHECK(IsValid());

  return !CallFtruncate(file_.get(), length);

}

bool File::Flush() {

  butil::ThreadRestrictions::AssertIOAllowed();

  DCHECK(IsValid());

  return !CallFsync(file_.get());

}

bool File::SetTimes(Time last_access_time, Time last_modified_time) {

  butil::ThreadRestrictions::AssertIOAllowed();

  DCHECK(IsValid());

  timeval times[2];

  times[0] = last_access_time.ToTimeVal();

  times[1] = last_modified_time.ToTimeVal();

  return !CallFutimes(file_.get(), times);

}

bool File::GetInfo(Info* info) {

  DCHECK(IsValid());

  stat_wrapper_t file_info;

  if (CallFstat(file_.get(), &file_info))

    return false;

  info->FromStat(file_info);

  return true;

}

File::Error File::Lock() {

  return CallFctnlFlock(file_.get(), true);

}

File::Error File::Unlock() {

  return CallFctnlFlock(file_.get(), false);

}

// Static.

File::Error File::OSErrorToFileError(int saved_errno) {

  switch (saved_errno) {

    case EACCES:

    case EISDIR:

    case EROFS:

    case EPERM:

      return FILE_ERROR_ACCESS_DENIED;

#if !defined(OS_NACL)  // ETXTBSY not defined by NaCl.

    case ETXTBSY:

      return FILE_ERROR_IN_USE;

#endif

    case EEXIST:

      return FILE_ERROR_EXISTS;

    case ENOENT:

      return FILE_ERROR_NOT_FOUND;

    case EMFILE:

      return FILE_ERROR_TOO_MANY_OPENED;

    case ENOMEM:

      return FILE_ERROR_NO_MEMORY;

    case ENOSPC:

      return FILE_ERROR_NO_SPACE;

    case ENOTDIR:

      return FILE_ERROR_NOT_A_DIRECTORY;

    default:

      return FILE_ERROR_FAILED;

  }

}

void File::SetPlatformFile(PlatformFile file) {

  DCHECK(!file_.is_valid());

  file_.reset(file);

}

}  // namespace butil