1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
use crate::fs::{asyncify, File};

use std::io;
use std::path::Path;

/// Options and flags which can be used to configure how a file is opened.
///
/// This builder exposes the ability to configure how a [`File`] is opened and
/// what operations are permitted on the open file. The [`File::open`] and
/// [`File::create`] methods are aliases for commonly used options using this
/// builder.
///
/// Generally speaking, when using `OpenOptions`, you'll first call [`new`],
/// then chain calls to methods to set each option, then call [`open`], passing
/// the path of the file you're trying to open. This will give you a
/// [`io::Result`][result] with a [`File`] inside that you can further operate
/// on.
///
/// This is a specialized version of [`std::fs::OpenOptions`] for usage from
/// the Tokio runtime.
///
/// `From<std::fs::OpenOptions>` is implemented for more advanced configuration
/// than the methods provided here.
///
/// [`new`]: OpenOptions::new
/// [`open`]: OpenOptions::open
/// [result]: std::io::Result
/// [`File`]: File
/// [`File::open`]: File::open
/// [`File::create`]: File::create
/// [`std::fs::OpenOptions`]: std::fs::OpenOptions
///
/// # Examples
///
/// Opening a file to read:
///
/// ```no_run
/// use tokio::fs::OpenOptions;
/// use std::io;
///
/// #[tokio::main]
/// async fn main() -> io::Result<()> {
///     let file = OpenOptions::new()
///         .read(true)
///         .open("foo.txt")
///         .await?;
///
///     Ok(())
/// }
/// ```
///
/// Opening a file for both reading and writing, as well as creating it if it
/// doesn't exist:
///
/// ```no_run
/// use tokio::fs::OpenOptions;
/// use std::io;
///
/// #[tokio::main]
/// async fn main() -> io::Result<()> {
///     let file = OpenOptions::new()
///         .read(true)
///         .write(true)
///         .create(true)
///         .open("foo.txt")
///         .await?;
///
///     Ok(())
/// }
/// ```
#[derive(Clone, Debug)]
pub struct OpenOptions(std::fs::OpenOptions);

impl OpenOptions {
    /// Creates a blank new set of options ready for configuration.
    ///
    /// All options are initially set to `false`.
    ///
    /// This is an async version of [`std::fs::OpenOptions::new`][std]
    ///
    /// [std]: std::fs::OpenOptions::new
    ///
    /// # Examples
    ///
    /// ```no_run
    /// use tokio::fs::OpenOptions;
    ///
    /// let mut options = OpenOptions::new();
    /// let future = options.read(true).open("foo.txt");
    /// ```
    pub fn new() -> OpenOptions {
        OpenOptions(std::fs::OpenOptions::new())
    }

    /// Sets the option for read access.
    ///
    /// This option, when true, will indicate that the file should be
    /// `read`-able if opened.
    ///
    /// This is an async version of [`std::fs::OpenOptions::read`][std]
    ///
    /// [std]: std::fs::OpenOptions::read
    ///
    /// # Examples
    ///
    /// ```no_run
    /// use tokio::fs::OpenOptions;
    /// use std::io;
    ///
    /// #[tokio::main]
    /// async fn main() -> io::Result<()> {
    ///     let file = OpenOptions::new()
    ///         .read(true)
    ///         .open("foo.txt")
    ///         .await?;
    ///
    ///     Ok(())
    /// }
    /// ```
    pub fn read(&mut self, read: bool) -> &mut OpenOptions {
        self.0.read(read);
        self
    }

    /// Sets the option for write access.
    ///
    /// This option, when true, will indicate that the file should be
    /// `write`-able if opened.
    ///
    /// This is an async version of [`std::fs::OpenOptions::write`][std]
    ///
    /// [std]: std::fs::OpenOptions::write
    ///
    /// # Examples
    ///
    /// ```no_run
    /// use tokio::fs::OpenOptions;
    /// use std::io;
    ///
    /// #[tokio::main]
    /// async fn main() -> io::Result<()> {
    ///     let file = OpenOptions::new()
    ///         .write(true)
    ///         .open("foo.txt")
    ///         .await?;
    ///
    ///     Ok(())
    /// }
    /// ```
    pub fn write(&mut self, write: bool) -> &mut OpenOptions {
        self.0.write(write);
        self
    }

    /// Sets the option for the append mode.
    ///
    /// This option, when true, means that writes will append to a file instead
    /// of overwriting previous contents.  Note that setting
    /// `.write(true).append(true)` has the same effect as setting only
    /// `.append(true)`.
    ///
    /// For most filesystems, the operating system guarantees that all writes are
    /// atomic: no writes get mangled because another process writes at the same
    /// time.
    ///
    /// One maybe obvious note when using append-mode: make sure that all data
    /// that belongs together is written to the file in one operation. This
    /// can be done by concatenating strings before passing them to [`write()`],
    /// or using a buffered writer (with a buffer of adequate size),
    /// and calling [`flush()`] when the message is complete.
    ///
    /// If a file is opened with both read and append access, beware that after
    /// opening, and after every write, the position for reading may be set at the
    /// end of the file. So, before writing, save the current position (using
    /// [`seek`]`(`[`SeekFrom`]`::`[`Current`]`(0))`), and restore it before the next read.
    ///
    /// This is an async version of [`std::fs::OpenOptions::append`][std]
    ///
    /// [std]: std::fs::OpenOptions::append
    ///
    /// ## Note
    ///
    /// This function doesn't create the file if it doesn't exist. Use the [`create`]
    /// method to do so.
    ///
    /// [`write()`]: crate::io::AsyncWriteExt::write
    /// [`flush()`]: crate::io::AsyncWriteExt::flush
    /// [`seek`]: crate::io::AsyncSeekExt::seek
    /// [`SeekFrom`]: std::io::SeekFrom
    /// [`Current`]: std::io::SeekFrom::Current
    /// [`create`]: OpenOptions::create
    ///
    /// # Examples
    ///
    /// ```no_run
    /// use tokio::fs::OpenOptions;
    /// use std::io;
    ///
    /// #[tokio::main]
    /// async fn main() -> io::Result<()> {
    ///     let file = OpenOptions::new()
    ///         .append(true)
    ///         .open("foo.txt")
    ///         .await?;
    ///
    ///     Ok(())
    /// }
    /// ```
    pub fn append(&mut self, append: bool) -> &mut OpenOptions {
        self.0.append(append);
        self
    }

    /// Sets the option for truncating a previous file.
    ///
    /// If a file is successfully opened with this option set it will truncate
    /// the file to 0 length if it already exists.
    ///
    /// The file must be opened with write access for truncate to work.
    ///
    /// This is an async version of [`std::fs::OpenOptions::truncate`][std]
    ///
    /// [std]: std::fs::OpenOptions::truncate
    ///
    /// # Examples
    ///
    /// ```no_run
    /// use tokio::fs::OpenOptions;
    /// use std::io;
    ///
    /// #[tokio::main]
    /// async fn main() -> io::Result<()> {
    ///     let file = OpenOptions::new()
    ///         .write(true)
    ///         .truncate(true)
    ///         .open("foo.txt")
    ///         .await?;
    ///
    ///     Ok(())
    /// }
    /// ```
    pub fn truncate(&mut self, truncate: bool) -> &mut OpenOptions {
        self.0.truncate(truncate);
        self
    }

    /// Sets the option for creating a new file.
    ///
    /// This option indicates whether a new file will be created if the file
    /// does not yet already exist.
    ///
    /// In order for the file to be created, [`write`] or [`append`] access must
    /// be used.
    ///
    /// This is an async version of [`std::fs::OpenOptions::create`][std]
    ///
    /// [std]: std::fs::OpenOptions::create
    /// [`write`]: OpenOptions::write
    /// [`append`]: OpenOptions::append
    ///
    /// # Examples
    ///
    /// ```no_run
    /// use tokio::fs::OpenOptions;
    /// use std::io;
    ///
    /// #[tokio::main]
    /// async fn main() -> io::Result<()> {
    ///     let file = OpenOptions::new()
    ///         .write(true)
    ///         .create(true)
    ///         .open("foo.txt")
    ///         .await?;
    ///
    ///     Ok(())
    /// }
    /// ```
    pub fn create(&mut self, create: bool) -> &mut OpenOptions {
        self.0.create(create);
        self
    }

    /// Sets the option to always create a new file.
    ///
    /// This option indicates whether a new file will be created.  No file is
    /// allowed to exist at the target location, also no (dangling) symlink.
    ///
    /// This option is useful because it is atomic. Otherwise between checking
    /// whether a file exists and creating a new one, the file may have been
    /// created by another process (a TOCTOU race condition / attack).
    ///
    /// If `.create_new(true)` is set, [`.create()`] and [`.truncate()`] are
    /// ignored.
    ///
    /// The file must be opened with write or append access in order to create a
    /// new file.
    ///
    /// This is an async version of [`std::fs::OpenOptions::create_new`][std]
    ///
    /// [std]: std::fs::OpenOptions::create_new
    /// [`.create()`]: OpenOptions::create
    /// [`.truncate()`]: OpenOptions::truncate
    ///
    /// # Examples
    ///
    /// ```no_run
    /// use tokio::fs::OpenOptions;
    /// use std::io;
    ///
    /// #[tokio::main]
    /// async fn main() -> io::Result<()> {
    ///     let file = OpenOptions::new()
    ///         .write(true)
    ///         .create_new(true)
    ///         .open("foo.txt")
    ///         .await?;
    ///
    ///     Ok(())
    /// }
    /// ```
    pub fn create_new(&mut self, create_new: bool) -> &mut OpenOptions {
        self.0.create_new(create_new);
        self
    }

    /// Opens a file at `path` with the options specified by `self`.
    ///
    /// This is an async version of [`std::fs::OpenOptions::open`][std]
    ///
    /// [std]: std::fs::OpenOptions::open
    ///
    /// # Errors
    ///
    /// This function will return an error under a number of different
    /// circumstances. Some of these error conditions are listed here, together
    /// with their [`ErrorKind`]. The mapping to [`ErrorKind`]s is not part of
    /// the compatibility contract of the function, especially the `Other` kind
    /// might change to more specific kinds in the future.
    ///
    /// * [`NotFound`]: The specified file does not exist and neither `create`
    ///   or `create_new` is set.
    /// * [`NotFound`]: One of the directory components of the file path does
    ///   not exist.
    /// * [`PermissionDenied`]: The user lacks permission to get the specified
    ///   access rights for the file.
    /// * [`PermissionDenied`]: The user lacks permission to open one of the
    ///   directory components of the specified path.
    /// * [`AlreadyExists`]: `create_new` was specified and the file already
    ///   exists.
    /// * [`InvalidInput`]: Invalid combinations of open options (truncate
    ///   without write access, no access mode set, etc.).
    /// * [`Other`]: One of the directory components of the specified file path
    ///   was not, in fact, a directory.
    /// * [`Other`]: Filesystem-level errors: full disk, write permission
    ///   requested on a read-only file system, exceeded disk quota, too many
    ///   open files, too long filename, too many symbolic links in the
    ///   specified path (Unix-like systems only), etc.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// use tokio::fs::OpenOptions;
    /// use std::io;
    ///
    /// #[tokio::main]
    /// async fn main() -> io::Result<()> {
    ///     let file = OpenOptions::new().open("foo.txt").await?;
    ///     Ok(())
    /// }
    /// ```
    ///
    /// [`ErrorKind`]: std::io::ErrorKind
    /// [`AlreadyExists`]: std::io::ErrorKind::AlreadyExists
    /// [`InvalidInput`]: std::io::ErrorKind::InvalidInput
    /// [`NotFound`]: std::io::ErrorKind::NotFound
    /// [`Other`]: std::io::ErrorKind::Other
    /// [`PermissionDenied`]: std::io::ErrorKind::PermissionDenied
    pub async fn open(&self, path: impl AsRef<Path>) -> io::Result<File> {
        let path = path.as_ref().to_owned();
        let opts = self.0.clone();

        let std = asyncify(move || opts.open(path)).await?;
        Ok(File::from_std(std))
    }

    /// Returns a mutable reference to the underlying `std::fs::OpenOptions`
    pub(super) fn as_inner_mut(&mut self) -> &mut std::fs::OpenOptions {
        &mut self.0
    }
}

feature! {
    #![unix]

    use std::os::unix::fs::OpenOptionsExt;

    impl OpenOptions {
        /// Sets the mode bits that a new file will be created with.
        ///
        /// If a new file is created as part of an `OpenOptions::open` call then this
        /// specified `mode` will be used as the permission bits for the new file.
        /// If no `mode` is set, the default of `0o666` will be used.
        /// The operating system masks out bits with the system's `umask`, to produce
        /// the final permissions.
        ///
        /// # Examples
        ///
        /// ```no_run
        /// use tokio::fs::OpenOptions;
        /// use std::io;
        ///
        /// #[tokio::main]
        /// async fn main() -> io::Result<()> {
        ///     let mut options = OpenOptions::new();
        ///     options.mode(0o644); // Give read/write for owner and read for others.
        ///     let file = options.open("foo.txt").await?;
        ///
        ///     Ok(())
        /// }
        /// ```
        pub fn mode(&mut self, mode: u32) -> &mut OpenOptions {
            self.as_inner_mut().mode(mode);
            self
        }

        /// Pass custom flags to the `flags` argument of `open`.
        ///
        /// The bits that define the access mode are masked out with `O_ACCMODE`, to
        /// ensure they do not interfere with the access mode set by Rusts options.
        ///
        /// Custom flags can only set flags, not remove flags set by Rusts options.
        /// This options overwrites any previously set custom flags.
        ///
        /// # Examples
        ///
        /// ```no_run
        /// use libc;
        /// use tokio::fs::OpenOptions;
        /// use std::io;
        ///
        /// #[tokio::main]
        /// async fn main() -> io::Result<()> {
        ///     let mut options = OpenOptions::new();
        ///     options.write(true);
        ///     if cfg!(unix) {
        ///         options.custom_flags(libc::O_NOFOLLOW);
        ///     }
        ///     let file = options.open("foo.txt").await?;
        ///
        ///     Ok(())
        /// }
        /// ```
        pub fn custom_flags(&mut self, flags: i32) -> &mut OpenOptions {
            self.as_inner_mut().custom_flags(flags);
            self
        }
    }
}

feature! {
    #![windows]

    use std::os::windows::fs::OpenOptionsExt;

    impl OpenOptions {
        /// Overrides the `dwDesiredAccess` argument to the call to [`CreateFile`]
        /// with the specified value.
        ///
        /// This will override the `read`, `write`, and `append` flags on the
        /// `OpenOptions` structure. This method provides fine-grained control over
        /// the permissions to read, write and append data, attributes (like hidden
        /// and system), and extended attributes.
        ///
        /// # Examples
        ///
        /// ```no_run
        /// use tokio::fs::OpenOptions;
        ///
        /// # #[tokio::main]
        /// # async fn main() -> std::io::Result<()> {
        /// // Open without read and write permission, for example if you only need
        /// // to call `stat` on the file
        /// let file = OpenOptions::new().access_mode(0).open("foo.txt").await?;
        /// # Ok(())
        /// # }
        /// ```
        ///
        /// [`CreateFile`]: https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilea
        pub fn access_mode(&mut self, access: u32) -> &mut OpenOptions {
            self.as_inner_mut().access_mode(access);
            self
        }

        /// Overrides the `dwShareMode` argument to the call to [`CreateFile`] with
        /// the specified value.
        ///
        /// By default `share_mode` is set to
        /// `FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE`. This allows
        /// other processes to read, write, and delete/rename the same file
        /// while it is open. Removing any of the flags will prevent other
        /// processes from performing the corresponding operation until the file
        /// handle is closed.
        ///
        /// # Examples
        ///
        /// ```no_run
        /// use tokio::fs::OpenOptions;
        ///
        /// # #[tokio::main]
        /// # async fn main() -> std::io::Result<()> {
        /// // Do not allow others to read or modify this file while we have it open
        /// // for writing.
        /// let file = OpenOptions::new()
        ///     .write(true)
        ///     .share_mode(0)
        ///     .open("foo.txt").await?;
        /// # Ok(())
        /// # }
        /// ```
        ///
        /// [`CreateFile`]: https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilea
        pub fn share_mode(&mut self, share: u32) -> &mut OpenOptions {
            self.as_inner_mut().share_mode(share);
            self
        }

        /// Sets extra flags for the `dwFileFlags` argument to the call to
        /// [`CreateFile2`] to the specified value (or combines it with
        /// `attributes` and `security_qos_flags` to set the `dwFlagsAndAttributes`
        /// for [`CreateFile`]).
        ///
        /// Custom flags can only set flags, not remove flags set by Rust's options.
        /// This option overwrites any previously set custom flags.
        ///
        /// # Examples
        ///
        /// ```no_run
        /// use winapi::um::winbase::FILE_FLAG_DELETE_ON_CLOSE;
        /// use tokio::fs::OpenOptions;
        ///
        /// # #[tokio::main]
        /// # async fn main() -> std::io::Result<()> {
        /// let file = OpenOptions::new()
        ///     .create(true)
        ///     .write(true)
        ///     .custom_flags(FILE_FLAG_DELETE_ON_CLOSE)
        ///     .open("foo.txt").await?;
        /// # Ok(())
        /// # }
        /// ```
        ///
        /// [`CreateFile`]: https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilea
        /// [`CreateFile2`]: https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfile2
        pub fn custom_flags(&mut self, flags: u32) -> &mut OpenOptions {
            self.as_inner_mut().custom_flags(flags);
            self
        }

        /// Sets the `dwFileAttributes` argument to the call to [`CreateFile2`] to
        /// the specified value (or combines it with `custom_flags` and
        /// `security_qos_flags` to set the `dwFlagsAndAttributes` for
        /// [`CreateFile`]).
        ///
        /// If a _new_ file is created because it does not yet exist and
        /// `.create(true)` or `.create_new(true)` are specified, the new file is
        /// given the attributes declared with `.attributes()`.
        ///
        /// If an _existing_ file is opened with `.create(true).truncate(true)`, its
        /// existing attributes are preserved and combined with the ones declared
        /// with `.attributes()`.
        ///
        /// In all other cases the attributes get ignored.
        ///
        /// # Examples
        ///
        /// ```no_run
        /// use winapi::um::winnt::FILE_ATTRIBUTE_HIDDEN;
        /// use tokio::fs::OpenOptions;
        ///
        /// # #[tokio::main]
        /// # async fn main() -> std::io::Result<()> {
        /// let file = OpenOptions::new()
        ///     .write(true)
        ///     .create(true)
        ///     .attributes(FILE_ATTRIBUTE_HIDDEN)
        ///     .open("foo.txt").await?;
        /// # Ok(())
        /// # }
        /// ```
        ///
        /// [`CreateFile`]: https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilea
        /// [`CreateFile2`]: https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfile2
        pub fn attributes(&mut self, attributes: u32) -> &mut OpenOptions {
            self.as_inner_mut().attributes(attributes);
            self
        }

        /// Sets the `dwSecurityQosFlags` argument to the call to [`CreateFile2`] to
        /// the specified value (or combines it with `custom_flags` and `attributes`
        /// to set the `dwFlagsAndAttributes` for [`CreateFile`]).
        ///
        /// By default `security_qos_flags` is not set. It should be specified when
        /// opening a named pipe, to control to which degree a server process can
        /// act on behalf of a client process (security impersonation level).
        ///
        /// When `security_qos_flags` is not set, a malicious program can gain the
        /// elevated privileges of a privileged Rust process when it allows opening
        /// user-specified paths, by tricking it into opening a named pipe. So
        /// arguably `security_qos_flags` should also be set when opening arbitrary
        /// paths. However the bits can then conflict with other flags, specifically
        /// `FILE_FLAG_OPEN_NO_RECALL`.
        ///
        /// For information about possible values, see [Impersonation Levels] on the
        /// Windows Dev Center site. The `SECURITY_SQOS_PRESENT` flag is set
        /// automatically when using this method.
        ///
        /// # Examples
        ///
        /// ```no_run
        /// use winapi::um::winbase::SECURITY_IDENTIFICATION;
        /// use tokio::fs::OpenOptions;
        ///
        /// # #[tokio::main]
        /// # async fn main() -> std::io::Result<()> {
        /// let file = OpenOptions::new()
        ///     .write(true)
        ///     .create(true)
        ///
        ///     // Sets the flag value to `SecurityIdentification`.
        ///     .security_qos_flags(SECURITY_IDENTIFICATION)
        ///
        ///     .open(r"\\.\pipe\MyPipe").await?;
        /// # Ok(())
        /// # }
        /// ```
        ///
        /// [`CreateFile`]: https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilea
        /// [`CreateFile2`]: https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfile2
        /// [Impersonation Levels]:
        ///     https://docs.microsoft.com/en-us/windows/win32/api/winnt/ne-winnt-security_impersonation_level
        pub fn security_qos_flags(&mut self, flags: u32) -> &mut OpenOptions {
            self.as_inner_mut().security_qos_flags(flags);
            self
        }
    }
}

impl From<std::fs::OpenOptions> for OpenOptions {
    fn from(options: std::fs::OpenOptions) -> OpenOptions {
        OpenOptions(options)
    }
}

impl Default for OpenOptions {
    fn default() -> Self {
        Self::new()
    }
}