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
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
use std::ffi::{CStr, CString};
use std::marker;
use std::ops::Range;
use std::path::Path;
use std::ptr;
use std::slice;

use libc::{c_char, c_int, c_uint, c_void, size_t};

use crate::util::{self, path_to_repo_path, Binding};
use crate::IntoCString;
use crate::{panic, raw, Error, IndexAddOption, IndexTime, Oid, Repository, Tree};

/// A structure to represent a git [index][1]
///
/// [1]: http://git-scm.com/book/en/Git-Internals-Git-Objects
pub struct Index {
    raw: *mut raw::git_index,
}

/// An iterator over the entries in an index
pub struct IndexEntries<'index> {
    range: Range<usize>,
    index: &'index Index,
}

/// An iterator over the conflicting entries in an index
pub struct IndexConflicts<'index> {
    conflict_iter: *mut raw::git_index_conflict_iterator,
    _marker: marker::PhantomData<&'index Index>,
}

/// A structure to represent the information returned when a conflict is detected in an index entry
pub struct IndexConflict {
    /// The ancestor index entry of the two conflicting index entries
    pub ancestor: Option<IndexEntry>,
    /// The index entry originating from the user's copy of the repository.
    /// Its contents conflict with 'their' index entry
    pub our: Option<IndexEntry>,
    /// The index entry originating from the external repository.
    /// Its contents conflict with 'our' index entry
    pub their: Option<IndexEntry>,
}

/// A callback function to filter index matches.
///
/// Used by `Index::{add_all,remove_all,update_all}`.  The first argument is the
/// path, and the second is the patchspec that matched it.  Return 0 to confirm
/// the operation on the item, > 0 to skip the item, and < 0 to abort the scan.
pub type IndexMatchedPath<'a> = dyn FnMut(&Path, &[u8]) -> i32 + 'a;

/// A structure to represent an entry or a file inside of an index.
///
/// All fields of an entry are public for modification and inspection. This is
/// also how a new index entry is created.
#[allow(missing_docs)]
pub struct IndexEntry {
    pub ctime: IndexTime,
    pub mtime: IndexTime,
    pub dev: u32,
    pub ino: u32,
    pub mode: u32,
    pub uid: u32,
    pub gid: u32,
    pub file_size: u32,
    pub id: Oid,
    pub flags: u16,
    pub flags_extended: u16,

    /// The path of this index entry as a byte vector. Regardless of the
    /// current platform, the directory separator is an ASCII forward slash
    /// (`0x2F`). There are no terminating or internal NUL characters, and no
    /// trailing slashes. Most of the time, paths will be valid utf-8 — but
    /// not always. For more information on the path storage format, see
    /// [these git docs][git-index-docs]. Note that libgit2 will take care of
    /// handling the prefix compression mentioned there.
    ///
    /// [git-index-docs]: https://github.com/git/git/blob/a08a83db2bf27f015bec9a435f6d73e223c21c5e/Documentation/technical/index-format.txt#L107-L124
    ///
    /// You can turn this value into a `std::ffi::CString` with
    /// `CString::new(&entry.path[..]).unwrap()`. To turn a reference into a
    /// `&std::path::Path`, see the `bytes2path()` function in the private,
    /// internal `util` module in this crate’s source code.
    pub path: Vec<u8>,
}

impl Index {
    /// Creates a new in-memory index.
    ///
    /// This index object cannot be read/written to the filesystem, but may be
    /// used to perform in-memory index operations.
    pub fn new() -> Result<Index, Error> {
        crate::init();
        let mut raw = ptr::null_mut();
        unsafe {
            try_call!(raw::git_index_new(&mut raw));
            Ok(Binding::from_raw(raw))
        }
    }

    /// Create a new bare Git index object as a memory representation of the Git
    /// index file in 'index_path', without a repository to back it.
    ///
    /// Since there is no ODB or working directory behind this index, any Index
    /// methods which rely on these (e.g. add_path) will fail.
    ///
    /// If you need an index attached to a repository, use the `index()` method
    /// on `Repository`.
    pub fn open(index_path: &Path) -> Result<Index, Error> {
        crate::init();
        let mut raw = ptr::null_mut();
        // Normal file path OK (does not need Windows conversion).
        let index_path = index_path.into_c_string()?;
        unsafe {
            try_call!(raw::git_index_open(&mut raw, index_path));
            Ok(Binding::from_raw(raw))
        }
    }

    /// Get index on-disk version.
    ///
    /// Valid return values are 2, 3, or 4.  If 3 is returned, an index
    /// with version 2 may be written instead, if the extension data in
    /// version 3 is not necessary.
    pub fn version(&self) -> u32 {
        unsafe { raw::git_index_version(self.raw) }
    }

    /// Set index on-disk version.
    ///
    /// Valid values are 2, 3, or 4.  If 2 is given, git_index_write may
    /// write an index with version 3 instead, if necessary to accurately
    /// represent the index.
    pub fn set_version(&mut self, version: u32) -> Result<(), Error> {
        unsafe {
            try_call!(raw::git_index_set_version(self.raw, version));
        }
        Ok(())
    }

    /// Add or update an index entry from an in-memory struct
    ///
    /// If a previous index entry exists that has the same path and stage as the
    /// given 'source_entry', it will be replaced. Otherwise, the 'source_entry'
    /// will be added.
    pub fn add(&mut self, entry: &IndexEntry) -> Result<(), Error> {
        let path = CString::new(&entry.path[..])?;

        // libgit2 encodes the length of the path in the lower bits of the
        // `flags` entry, so mask those out and recalculate here to ensure we
        // don't corrupt anything.
        let mut flags = entry.flags & !raw::GIT_INDEX_ENTRY_NAMEMASK;

        if entry.path.len() < raw::GIT_INDEX_ENTRY_NAMEMASK as usize {
            flags |= entry.path.len() as u16;
        } else {
            flags |= raw::GIT_INDEX_ENTRY_NAMEMASK;
        }

        unsafe {
            let raw = raw::git_index_entry {
                dev: entry.dev,
                ino: entry.ino,
                mode: entry.mode,
                uid: entry.uid,
                gid: entry.gid,
                file_size: entry.file_size,
                id: *entry.id.raw(),
                flags,
                flags_extended: entry.flags_extended,
                path: path.as_ptr(),
                mtime: raw::git_index_time {
                    seconds: entry.mtime.seconds(),
                    nanoseconds: entry.mtime.nanoseconds(),
                },
                ctime: raw::git_index_time {
                    seconds: entry.ctime.seconds(),
                    nanoseconds: entry.ctime.nanoseconds(),
                },
            };
            try_call!(raw::git_index_add(self.raw, &raw));
            Ok(())
        }
    }

    /// Add or update an index entry from a buffer in memory
    ///
    /// This method will create a blob in the repository that owns the index and
    /// then add the index entry to the index. The path of the entry represents
    /// the position of the blob relative to the repository's root folder.
    ///
    /// If a previous index entry exists that has the same path as the given
    /// 'entry', it will be replaced. Otherwise, the 'entry' will be added.
    /// The id and the file_size of the 'entry' are updated with the real value
    /// of the blob.
    ///
    /// This forces the file to be added to the index, not looking at gitignore
    /// rules.
    ///
    /// If this file currently is the result of a merge conflict, this file will
    /// no longer be marked as conflicting. The data about the conflict will be
    /// moved to the "resolve undo" (REUC) section.
    pub fn add_frombuffer(&mut self, entry: &IndexEntry, data: &[u8]) -> Result<(), Error> {
        let path = CString::new(&entry.path[..])?;

        // libgit2 encodes the length of the path in the lower bits of the
        // `flags` entry, so mask those out and recalculate here to ensure we
        // don't corrupt anything.
        let mut flags = entry.flags & !raw::GIT_INDEX_ENTRY_NAMEMASK;

        if entry.path.len() < raw::GIT_INDEX_ENTRY_NAMEMASK as usize {
            flags |= entry.path.len() as u16;
        } else {
            flags |= raw::GIT_INDEX_ENTRY_NAMEMASK;
        }

        unsafe {
            let raw = raw::git_index_entry {
                dev: entry.dev,
                ino: entry.ino,
                mode: entry.mode,
                uid: entry.uid,
                gid: entry.gid,
                file_size: entry.file_size,
                id: *entry.id.raw(),
                flags,
                flags_extended: entry.flags_extended,
                path: path.as_ptr(),
                mtime: raw::git_index_time {
                    seconds: entry.mtime.seconds(),
                    nanoseconds: entry.mtime.nanoseconds(),
                },
                ctime: raw::git_index_time {
                    seconds: entry.ctime.seconds(),
                    nanoseconds: entry.ctime.nanoseconds(),
                },
            };

            let ptr = data.as_ptr() as *const c_void;
            let len = data.len() as size_t;
            try_call!(raw::git_index_add_frombuffer(self.raw, &raw, ptr, len));
            Ok(())
        }
    }

    /// Add or update an index entry from a file on disk
    ///
    /// The file path must be relative to the repository's working folder and
    /// must be readable.
    ///
    /// This method will fail in bare index instances.
    ///
    /// This forces the file to be added to the index, not looking at gitignore
    /// rules.
    ///
    /// If this file currently is the result of a merge conflict, this file will
    /// no longer be marked as conflicting. The data about the conflict will be
    /// moved to the "resolve undo" (REUC) section.
    pub fn add_path(&mut self, path: &Path) -> Result<(), Error> {
        let posix_path = path_to_repo_path(path)?;
        unsafe {
            try_call!(raw::git_index_add_bypath(self.raw, posix_path));
            Ok(())
        }
    }

    /// Add or update index entries matching files in the working directory.
    ///
    /// This method will fail in bare index instances.
    ///
    /// The `pathspecs` are a list of file names or shell glob patterns that
    /// will matched against files in the repository's working directory. Each
    /// file that matches will be added to the index (either updating an
    /// existing entry or adding a new entry). You can disable glob expansion
    /// and force exact matching with the `AddDisablePathspecMatch` flag.
    ///
    /// Files that are ignored will be skipped (unlike `add_path`). If a file is
    /// already tracked in the index, then it will be updated even if it is
    /// ignored. Pass the `AddForce` flag to skip the checking of ignore rules.
    ///
    /// To emulate `git add -A` and generate an error if the pathspec contains
    /// the exact path of an ignored file (when not using `AddForce`), add the
    /// `AddCheckPathspec` flag. This checks that each entry in `pathspecs`
    /// that is an exact match to a filename on disk is either not ignored or
    /// already in the index. If this check fails, the function will return
    /// an error.
    ///
    /// To emulate `git add -A` with the "dry-run" option, just use a callback
    /// function that always returns a positive value. See below for details.
    ///
    /// If any files are currently the result of a merge conflict, those files
    /// will no longer be marked as conflicting. The data about the conflicts
    /// will be moved to the "resolve undo" (REUC) section.
    ///
    /// If you provide a callback function, it will be invoked on each matching
    /// item in the working directory immediately before it is added to /
    /// updated in the index. Returning zero will add the item to the index,
    /// greater than zero will skip the item, and less than zero will abort the
    /// scan an return an error to the caller.
    ///
    /// # Example
    ///
    /// Emulate `git add *`:
    ///
    /// ```no_run
    /// use git2::{Index, IndexAddOption, Repository};
    ///
    /// let repo = Repository::open("/path/to/a/repo").expect("failed to open");
    /// let mut index = repo.index().expect("cannot get the Index file");
    /// index.add_all(["*"].iter(), IndexAddOption::DEFAULT, None);
    /// index.write();
    /// ```
    pub fn add_all<T, I>(
        &mut self,
        pathspecs: I,
        flag: IndexAddOption,
        mut cb: Option<&mut IndexMatchedPath<'_>>,
    ) -> Result<(), Error>
    where
        T: IntoCString,
        I: IntoIterator<Item = T>,
    {
        let (_a, _b, raw_strarray) = crate::util::iter2cstrs_paths(pathspecs)?;
        let ptr = cb.as_mut();
        let callback = ptr
            .as_ref()
            .map(|_| index_matched_path_cb as extern "C" fn(_, _, _) -> _);
        unsafe {
            try_call!(raw::git_index_add_all(
                self.raw,
                &raw_strarray,
                flag.bits() as c_uint,
                callback,
                ptr.map(|p| p as *mut _).unwrap_or(ptr::null_mut()) as *mut c_void
            ));
        }
        Ok(())
    }

    /// Clear the contents (all the entries) of an index object.
    ///
    /// This clears the index object in memory; changes must be explicitly
    /// written to disk for them to take effect persistently via `write_*`.
    pub fn clear(&mut self) -> Result<(), Error> {
        unsafe {
            try_call!(raw::git_index_clear(self.raw));
        }
        Ok(())
    }

    /// Get the count of entries currently in the index
    pub fn len(&self) -> usize {
        unsafe { raw::git_index_entrycount(&*self.raw) as usize }
    }

    /// Return `true` is there is no entry in the index
    pub fn is_empty(&self) -> bool {
        self.len() == 0
    }

    /// Get one of the entries in the index by its position.
    pub fn get(&self, n: usize) -> Option<IndexEntry> {
        unsafe {
            let ptr = raw::git_index_get_byindex(self.raw, n as size_t);
            if ptr.is_null() {
                None
            } else {
                Some(Binding::from_raw(*ptr))
            }
        }
    }

    /// Get an iterator over the entries in this index.
    pub fn iter(&self) -> IndexEntries<'_> {
        IndexEntries {
            range: 0..self.len(),
            index: self,
        }
    }

    /// Get an iterator over the index entries that have conflicts
    pub fn conflicts(&self) -> Result<IndexConflicts<'_>, Error> {
        crate::init();
        let mut conflict_iter = ptr::null_mut();
        unsafe {
            try_call!(raw::git_index_conflict_iterator_new(
                &mut conflict_iter,
                self.raw
            ));
            Ok(Binding::from_raw(conflict_iter))
        }
    }

    /// Get one of the entries in the index by its path.
    pub fn get_path(&self, path: &Path, stage: i32) -> Option<IndexEntry> {
        let path = path_to_repo_path(path).unwrap();
        unsafe {
            let ptr = call!(raw::git_index_get_bypath(self.raw, path, stage as c_int));
            if ptr.is_null() {
                None
            } else {
                Some(Binding::from_raw(*ptr))
            }
        }
    }

    /// Does this index have conflicts?
    ///
    /// Returns `true` if the index contains conflicts, `false` if it does not.
    pub fn has_conflicts(&self) -> bool {
        unsafe { raw::git_index_has_conflicts(self.raw) == 1 }
    }

    /// Get the full path to the index file on disk.
    ///
    /// Returns `None` if this is an in-memory index.
    pub fn path(&self) -> Option<&Path> {
        unsafe { crate::opt_bytes(self, raw::git_index_path(&*self.raw)).map(util::bytes2path) }
    }

    /// Update the contents of an existing index object in memory by reading
    /// from the hard disk.
    ///
    /// If force is true, this performs a "hard" read that discards in-memory
    /// changes and always reloads the on-disk index data. If there is no
    /// on-disk version, the index will be cleared.
    ///
    /// If force is false, this does a "soft" read that reloads the index data
    /// from disk only if it has changed since the last time it was loaded.
    /// Purely in-memory index data will be untouched. Be aware: if there are
    /// changes on disk, unwritten in-memory changes are discarded.
    pub fn read(&mut self, force: bool) -> Result<(), Error> {
        unsafe {
            try_call!(raw::git_index_read(self.raw, force));
        }
        Ok(())
    }

    /// Read a tree into the index file with stats
    ///
    /// The current index contents will be replaced by the specified tree.
    pub fn read_tree(&mut self, tree: &Tree<'_>) -> Result<(), Error> {
        unsafe {
            try_call!(raw::git_index_read_tree(self.raw, &*tree.raw()));
        }
        Ok(())
    }

    /// Remove an entry from the index
    pub fn remove(&mut self, path: &Path, stage: i32) -> Result<(), Error> {
        let path = path_to_repo_path(path)?;
        unsafe {
            try_call!(raw::git_index_remove(self.raw, path, stage as c_int));
        }
        Ok(())
    }

    /// Remove an index entry corresponding to a file on disk.
    ///
    /// The file path must be relative to the repository's working folder. It
    /// may exist.
    ///
    /// If this file currently is the result of a merge conflict, this file will
    /// no longer be marked as conflicting. The data about the conflict will be
    /// moved to the "resolve undo" (REUC) section.
    pub fn remove_path(&mut self, path: &Path) -> Result<(), Error> {
        let path = path_to_repo_path(path)?;
        unsafe {
            try_call!(raw::git_index_remove_bypath(self.raw, path));
        }
        Ok(())
    }

    /// Remove all entries from the index under a given directory.
    pub fn remove_dir(&mut self, path: &Path, stage: i32) -> Result<(), Error> {
        let path = path_to_repo_path(path)?;
        unsafe {
            try_call!(raw::git_index_remove_directory(
                self.raw,
                path,
                stage as c_int
            ));
        }
        Ok(())
    }

    /// Remove all matching index entries.
    ///
    /// If you provide a callback function, it will be invoked on each matching
    /// item in the index immediately before it is removed. Return 0 to remove
    /// the item, > 0 to skip the item, and < 0 to abort the scan.
    pub fn remove_all<T, I>(
        &mut self,
        pathspecs: I,
        mut cb: Option<&mut IndexMatchedPath<'_>>,
    ) -> Result<(), Error>
    where
        T: IntoCString,
        I: IntoIterator<Item = T>,
    {
        let (_a, _b, raw_strarray) = crate::util::iter2cstrs_paths(pathspecs)?;
        let ptr = cb.as_mut();
        let callback = ptr
            .as_ref()
            .map(|_| index_matched_path_cb as extern "C" fn(_, _, _) -> _);
        unsafe {
            try_call!(raw::git_index_remove_all(
                self.raw,
                &raw_strarray,
                callback,
                ptr.map(|p| p as *mut _).unwrap_or(ptr::null_mut()) as *mut c_void
            ));
        }
        Ok(())
    }

    /// Update all index entries to match the working directory
    ///
    /// This method will fail in bare index instances.
    ///
    /// This scans the existing index entries and synchronizes them with the
    /// working directory, deleting them if the corresponding working directory
    /// file no longer exists otherwise updating the information (including
    /// adding the latest version of file to the ODB if needed).
    ///
    /// If you provide a callback function, it will be invoked on each matching
    /// item in the index immediately before it is updated (either refreshed or
    /// removed depending on working directory state). Return 0 to proceed with
    /// updating the item, > 0 to skip the item, and < 0 to abort the scan.
    pub fn update_all<T, I>(
        &mut self,
        pathspecs: I,
        mut cb: Option<&mut IndexMatchedPath<'_>>,
    ) -> Result<(), Error>
    where
        T: IntoCString,
        I: IntoIterator<Item = T>,
    {
        let (_a, _b, raw_strarray) = crate::util::iter2cstrs_paths(pathspecs)?;
        let ptr = cb.as_mut();
        let callback = ptr
            .as_ref()
            .map(|_| index_matched_path_cb as extern "C" fn(_, _, _) -> _);
        unsafe {
            try_call!(raw::git_index_update_all(
                self.raw,
                &raw_strarray,
                callback,
                ptr.map(|p| p as *mut _).unwrap_or(ptr::null_mut()) as *mut c_void
            ));
        }
        Ok(())
    }

    /// Write an existing index object from memory back to disk using an atomic
    /// file lock.
    pub fn write(&mut self) -> Result<(), Error> {
        unsafe {
            try_call!(raw::git_index_write(self.raw));
        }
        Ok(())
    }

    /// Write the index as a tree.
    ///
    /// This method will scan the index and write a representation of its
    /// current state back to disk; it recursively creates tree objects for each
    /// of the subtrees stored in the index, but only returns the OID of the
    /// root tree. This is the OID that can be used e.g. to create a commit.
    ///
    /// The index instance cannot be bare, and needs to be associated to an
    /// existing repository.
    ///
    /// The index must not contain any file in conflict.
    pub fn write_tree(&mut self) -> Result<Oid, Error> {
        let mut raw = raw::git_oid {
            id: [0; raw::GIT_OID_RAWSZ],
        };
        unsafe {
            try_call!(raw::git_index_write_tree(&mut raw, self.raw));
            Ok(Binding::from_raw(&raw as *const _))
        }
    }

    /// Write the index as a tree to the given repository
    ///
    /// This is the same as `write_tree` except that the destination repository
    /// can be chosen.
    pub fn write_tree_to(&mut self, repo: &Repository) -> Result<Oid, Error> {
        let mut raw = raw::git_oid {
            id: [0; raw::GIT_OID_RAWSZ],
        };
        unsafe {
            try_call!(raw::git_index_write_tree_to(&mut raw, self.raw, repo.raw()));
            Ok(Binding::from_raw(&raw as *const _))
        }
    }
}

impl Binding for Index {
    type Raw = *mut raw::git_index;
    unsafe fn from_raw(raw: *mut raw::git_index) -> Index {
        Index { raw }
    }
    fn raw(&self) -> *mut raw::git_index {
        self.raw
    }
}

impl<'index> Binding for IndexConflicts<'index> {
    type Raw = *mut raw::git_index_conflict_iterator;

    unsafe fn from_raw(raw: *mut raw::git_index_conflict_iterator) -> IndexConflicts<'index> {
        IndexConflicts {
            conflict_iter: raw,
            _marker: marker::PhantomData,
        }
    }
    fn raw(&self) -> *mut raw::git_index_conflict_iterator {
        self.conflict_iter
    }
}

extern "C" fn index_matched_path_cb(
    path: *const c_char,
    matched_pathspec: *const c_char,
    payload: *mut c_void,
) -> c_int {
    unsafe {
        let path = CStr::from_ptr(path).to_bytes();
        let matched_pathspec = CStr::from_ptr(matched_pathspec).to_bytes();

        panic::wrap(|| {
            let payload = payload as *mut &mut IndexMatchedPath<'_>;
            (*payload)(util::bytes2path(path), matched_pathspec) as c_int
        })
        .unwrap_or(-1)
    }
}

impl Drop for Index {
    fn drop(&mut self) {
        unsafe { raw::git_index_free(self.raw) }
    }
}

impl<'index> Drop for IndexConflicts<'index> {
    fn drop(&mut self) {
        unsafe { raw::git_index_conflict_iterator_free(self.conflict_iter) }
    }
}

impl<'index> Iterator for IndexEntries<'index> {
    type Item = IndexEntry;
    fn next(&mut self) -> Option<IndexEntry> {
        self.range.next().map(|i| self.index.get(i).unwrap())
    }
}

impl<'index> Iterator for IndexConflicts<'index> {
    type Item = Result<IndexConflict, Error>;
    fn next(&mut self) -> Option<Result<IndexConflict, Error>> {
        let mut ancestor = ptr::null();
        let mut our = ptr::null();
        let mut their = ptr::null();
        unsafe {
            try_call_iter!(raw::git_index_conflict_next(
                &mut ancestor,
                &mut our,
                &mut their,
                self.conflict_iter
            ));
            Some(Ok(IndexConflict {
                ancestor: match ancestor.is_null() {
                    false => Some(IndexEntry::from_raw(*ancestor)),
                    true => None,
                },
                our: match our.is_null() {
                    false => Some(IndexEntry::from_raw(*our)),
                    true => None,
                },
                their: match their.is_null() {
                    false => Some(IndexEntry::from_raw(*their)),
                    true => None,
                },
            }))
        }
    }
}

impl Binding for IndexEntry {
    type Raw = raw::git_index_entry;

    unsafe fn from_raw(raw: raw::git_index_entry) -> IndexEntry {
        let raw::git_index_entry {
            ctime,
            mtime,
            dev,
            ino,
            mode,
            uid,
            gid,
            file_size,
            id,
            flags,
            flags_extended,
            path,
        } = raw;

        // libgit2 encodes the length of the path in the lower bits of `flags`,
        // but if the length exceeds the number of bits then the path is
        // nul-terminated.
        let mut pathlen = (flags & raw::GIT_INDEX_ENTRY_NAMEMASK) as usize;
        if pathlen == raw::GIT_INDEX_ENTRY_NAMEMASK as usize {
            pathlen = CStr::from_ptr(path).to_bytes().len();
        }

        let path = slice::from_raw_parts(path as *const u8, pathlen);

        IndexEntry {
            dev,
            ino,
            mode,
            uid,
            gid,
            file_size,
            id: Binding::from_raw(&id as *const _),
            flags,
            flags_extended,
            path: path.to_vec(),
            mtime: Binding::from_raw(mtime),
            ctime: Binding::from_raw(ctime),
        }
    }

    fn raw(&self) -> raw::git_index_entry {
        // not implemented, may require a CString in storage
        panic!()
    }
}

#[cfg(test)]
mod tests {
    use std::fs::{self, File};
    use std::path::Path;
    use tempfile::TempDir;

    use crate::{Index, IndexEntry, IndexTime, Oid, Repository, ResetType};

    #[test]
    fn smoke() {
        let mut index = Index::new().unwrap();
        assert!(index.add_path(&Path::new(".")).is_err());
        index.clear().unwrap();
        assert_eq!(index.len(), 0);
        assert!(index.get(0).is_none());
        assert!(index.path().is_none());
        assert!(index.read(true).is_err());
    }

    #[test]
    fn smoke_from_repo() {
        let (_td, repo) = crate::test::repo_init();
        let mut index = repo.index().unwrap();
        assert_eq!(
            index.path().map(|s| s.to_path_buf()),
            Some(repo.path().join("index"))
        );
        Index::open(&repo.path().join("index")).unwrap();

        index.clear().unwrap();
        index.read(true).unwrap();
        index.write().unwrap();
        index.write_tree().unwrap();
        index.write_tree_to(&repo).unwrap();
    }

    #[test]
    fn add_all() {
        let (_td, repo) = crate::test::repo_init();
        let mut index = repo.index().unwrap();

        let root = repo.path().parent().unwrap();
        fs::create_dir(&root.join("foo")).unwrap();
        File::create(&root.join("foo/bar")).unwrap();
        let mut called = false;
        index
            .add_all(
                ["foo"].iter(),
                crate::IndexAddOption::DEFAULT,
                Some(&mut |a: &Path, b: &[u8]| {
                    assert!(!called);
                    called = true;
                    assert_eq!(b, b"foo");
                    assert_eq!(a, Path::new("foo/bar"));
                    0
                }),
            )
            .unwrap();
        assert!(called);

        called = false;
        index
            .remove_all(
                ["."].iter(),
                Some(&mut |a: &Path, b: &[u8]| {
                    assert!(!called);
                    called = true;
                    assert_eq!(b, b".");
                    assert_eq!(a, Path::new("foo/bar"));
                    0
                }),
            )
            .unwrap();
        assert!(called);
    }

    #[test]
    fn smoke_add() {
        let (_td, repo) = crate::test::repo_init();
        let mut index = repo.index().unwrap();

        let root = repo.path().parent().unwrap();
        fs::create_dir(&root.join("foo")).unwrap();
        File::create(&root.join("foo/bar")).unwrap();
        index.add_path(Path::new("foo/bar")).unwrap();
        index.write().unwrap();
        assert_eq!(index.iter().count(), 1);

        // Make sure we can use this repo somewhere else now.
        let id = index.write_tree().unwrap();
        let tree = repo.find_tree(id).unwrap();
        let sig = repo.signature().unwrap();
        let id = repo.refname_to_id("HEAD").unwrap();
        let parent = repo.find_commit(id).unwrap();
        let commit = repo
            .commit(Some("HEAD"), &sig, &sig, "commit", &tree, &[&parent])
            .unwrap();
        let obj = repo.find_object(commit, None).unwrap();
        repo.reset(&obj, ResetType::Hard, None).unwrap();

        let td2 = TempDir::new().unwrap();
        let url = crate::test::path2url(&root);
        let repo = Repository::clone(&url, td2.path()).unwrap();
        let obj = repo.find_object(commit, None).unwrap();
        repo.reset(&obj, ResetType::Hard, None).unwrap();
    }

    #[test]
    fn add_then_read() {
        let mut index = Index::new().unwrap();
        assert!(index.add(&entry()).is_err());

        let mut index = Index::new().unwrap();
        let mut e = entry();
        e.path = b"foobar".to_vec();
        index.add(&e).unwrap();
        let e = index.get(0).unwrap();
        assert_eq!(e.path.len(), 6);
    }

    #[test]
    fn add_frombuffer_then_read() {
        let (_td, repo) = crate::test::repo_init();
        let mut index = repo.index().unwrap();

        let mut e = entry();
        e.path = b"foobar".to_vec();
        let content = b"the contents";
        index.add_frombuffer(&e, content).unwrap();
        let e = index.get(0).unwrap();
        assert_eq!(e.path.len(), 6);

        let b = repo.find_blob(e.id).unwrap();
        assert_eq!(b.content(), content);
    }

    fn entry() -> IndexEntry {
        IndexEntry {
            ctime: IndexTime::new(0, 0),
            mtime: IndexTime::new(0, 0),
            dev: 0,
            ino: 0,
            mode: 0o100644,
            uid: 0,
            gid: 0,
            file_size: 0,
            id: Oid::from_bytes(&[0; 20]).unwrap(),
            flags: 0,
            flags_extended: 0,
            path: Vec::new(),
        }
    }
}