| blob | 43a8231a9f95fee124ea26d80ac18eba3c4ac12b |
1 '\" t
2 .\" Title: gitformat-index
3 .\" Author: [FIXME: author] [see http://www.docbook.org/tdg5/en/html/author]
4 .\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
5 .\" Date: 2024-03-25
6 .\" Manual: Git Manual
7 .\" Source: Git 2.44.0.368.gc75fd8d815
8 .\" Language: English
9 .\"
10 .TH "GITFORMAT\-INDEX" "5" "2024\-03\-25" "Git 2\&.44\&.0\&.368\&.gc75fd8" "Git Manual"
11 .\" -----------------------------------------------------------------
12 .\" * Define some portability stuff
13 .\" -----------------------------------------------------------------
14 .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
15 .\" http://bugs.debian.org/507673
16 .\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
17 .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
18 .ie \n(.g .ds Aq \(aq
19 .el .ds Aq '
20 .\" -----------------------------------------------------------------
21 .\" * set default formatting
22 .\" -----------------------------------------------------------------
23 .\" disable hyphenation
24 .nh
25 .\" disable justification (adjust text to left margin only)
26 .ad l
27 .\" -----------------------------------------------------------------
28 .\" * MAIN CONTENT STARTS HERE *
29 .\" -----------------------------------------------------------------
30 .SH "NAME"
31 gitformat-index \- Git index format
32 .SH "SYNOPSIS"
33 .sp
34 .nf
35 $GIT_DIR/index
36 .fi
37 .sp
38 .SH "DESCRIPTION"
39 .sp
40 Git index format
41 .SH "THE GIT INDEX FILE HAS THE FOLLOWING FORMAT"
42 .sp
43 .if n \{\
44 .RS 4
45 .\}
46 .nf
47 All binary numbers are in network byte order\&.
48 In a repository using the traditional SHA\-1, checksums and object IDs
49 (object names) mentioned below are all computed using SHA\-1\&. Similarly,
50 in SHA\-256 repositories, these values are computed using SHA\-256\&.
51 Version 2 is described here unless stated otherwise\&.
52 .fi
53 .if n \{\
54 .RE
55 .\}
56 .sp
57 .RS 4
58 .ie n \{\
59 \h'-04'\(bu\h'+03'\c
60 .\}
61 .el \{\
62 .sp -1
63 .IP \(bu 2.3
64 .\}
65 A 12\-byte header consisting of
66 .sp
67 .if n \{\
68 .RS 4
69 .\}
70 .nf
71 4\-byte signature:
72 The signature is { \*(AqD\*(Aq, \*(AqI\*(Aq, \*(AqR\*(Aq, \*(AqC\*(Aq } (stands for "dircache")
73 .fi
74 .if n \{\
75 .RE
76 .\}
77 .sp
78 .if n \{\
79 .RS 4
80 .\}
81 .nf
82 4\-byte version number:
83 The current supported versions are 2, 3 and 4\&.
84 .fi
85 .if n \{\
86 .RE
87 .\}
88 .sp
89 .if n \{\
90 .RS 4
91 .\}
92 .nf
93 32\-bit number of index entries\&.
94 .fi
95 .if n \{\
96 .RE
97 .\}
98 .RE
99 .sp
100 .RS 4
101 .ie n \{\
102 \h'-04'\(bu\h'+03'\c
103 .\}
104 .el \{\
105 .sp -1
106 .IP \(bu 2.3
107 .\}
108 A number of sorted index entries (see below)\&.
109 .RE
110 .sp
111 .RS 4
112 .ie n \{\
113 \h'-04'\(bu\h'+03'\c
114 .\}
115 .el \{\
116 .sp -1
117 .IP \(bu 2.3
118 .\}
119 Extensions
120 .sp
121 .if n \{\
122 .RS 4
123 .\}
124 .nf
125 Extensions are identified by signature\&. Optional extensions can
126 be ignored if Git does not understand them\&.
127 .fi
128 .if n \{\
129 .RE
130 .\}
131 .sp
132 .if n \{\
133 .RS 4
134 .\}
135 .nf
136 4\-byte extension signature\&. If the first byte is \*(AqA\*(Aq\&.\&.\*(AqZ\*(Aq the
137 extension is optional and can be ignored\&.
138 .fi
139 .if n \{\
140 .RE
141 .\}
142 .sp
143 .if n \{\
144 .RS 4
145 .\}
146 .nf
147 32\-bit size of the extension
148 .fi
149 .if n \{\
150 .RE
151 .\}
152 .sp
153 .if n \{\
154 .RS 4
155 .\}
156 .nf
157 Extension data
158 .fi
159 .if n \{\
160 .RE
161 .\}
162 .RE
163 .sp
164 .RS 4
165 .ie n \{\
166 \h'-04'\(bu\h'+03'\c
167 .\}
168 .el \{\
169 .sp -1
170 .IP \(bu 2.3
171 .\}
172 Hash checksum over the content of the index file before this checksum\&.
173 .RE
174 .SH "INDEX ENTRY"
175 .sp
176 .if n \{\
177 .RS 4
178 .\}
179 .nf
180 Index entries are sorted in ascending order on the name field,
181 interpreted as a string of unsigned bytes (i\&.e\&. memcmp() order, no
182 localization, no special casing of directory separator \*(Aq/\*(Aq)\&. Entries
183 with the same name are sorted by their stage field\&.
184 .fi
185 .if n \{\
186 .RE
187 .\}
188 .sp
189 .if n \{\
190 .RS 4
191 .\}
192 .nf
193 An index entry typically represents a file\&. However, if sparse\-checkout
194 is enabled in cone mode (`core\&.sparseCheckoutCone` is enabled) and the
195 `extensions\&.sparseIndex` extension is enabled, then the index may
196 contain entries for directories outside of the sparse\-checkout definition\&.
197 These entries have mode `040000`, include the `SKIP_WORKTREE` bit, and
198 the path ends in a directory separator\&.
199 .fi
200 .if n \{\
201 .RE
202 .\}
203 .sp
204 .if n \{\
205 .RS 4
206 .\}
207 .nf
208 32\-bit ctime seconds, the last time a file\*(Aqs metadata changed
209 this is stat(2) data
210 .fi
211 .if n \{\
212 .RE
213 .\}
214 .sp
215 .if n \{\
216 .RS 4
217 .\}
218 .nf
219 32\-bit ctime nanosecond fractions
220 this is stat(2) data
221 .fi
222 .if n \{\
223 .RE
224 .\}
225 .sp
226 .if n \{\
227 .RS 4
228 .\}
229 .nf
230 32\-bit mtime seconds, the last time a file\*(Aqs data changed
231 this is stat(2) data
232 .fi
233 .if n \{\
234 .RE
235 .\}
236 .sp
237 .if n \{\
238 .RS 4
239 .\}
240 .nf
241 32\-bit mtime nanosecond fractions
242 this is stat(2) data
243 .fi
244 .if n \{\
245 .RE
246 .\}
247 .sp
248 .if n \{\
249 .RS 4
250 .\}
251 .nf
252 32\-bit dev
253 this is stat(2) data
254 .fi
255 .if n \{\
256 .RE
257 .\}
258 .sp
259 .if n \{\
260 .RS 4
261 .\}
262 .nf
263 32\-bit ino
264 this is stat(2) data
265 .fi
266 .if n \{\
267 .RE
268 .\}
269 .sp
270 .if n \{\
271 .RS 4
272 .\}
273 .nf
274 32\-bit mode, split into (high to low bits)
275 .fi
276 .if n \{\
277 .RE
278 .\}
279 .sp
280 .if n \{\
281 .RS 4
282 .\}
283 .nf
284 16\-bit unused, must be zero
285 .fi
286 .if n \{\
287 .RE
288 .\}
289 .sp
290 .if n \{\
291 .RS 4
292 .\}
293 .nf
294 4\-bit object type
295 valid values in binary are 1000 (regular file), 1010 (symbolic link)
296 and 1110 (gitlink)
297 .fi
298 .if n \{\
299 .RE
300 .\}
301 .sp
302 .if n \{\
303 .RS 4
304 .\}
305 .nf
306 3\-bit unused, must be zero
307 .fi
308 .if n \{\
309 .RE
310 .\}
311 .sp
312 .if n \{\
313 .RS 4
314 .\}
315 .nf
316 9\-bit unix permission\&. Only 0755 and 0644 are valid for regular files\&.
317 Symbolic links and gitlinks have value 0 in this field\&.
318 .fi
319 .if n \{\
320 .RE
321 .\}
322 .sp
323 .if n \{\
324 .RS 4
325 .\}
326 .nf
327 32\-bit uid
328 this is stat(2) data
329 .fi
330 .if n \{\
331 .RE
332 .\}
333 .sp
334 .if n \{\
335 .RS 4
336 .\}
337 .nf
338 32\-bit gid
339 this is stat(2) data
340 .fi
341 .if n \{\
342 .RE
343 .\}
344 .sp
345 .if n \{\
346 .RS 4
347 .\}
348 .nf
349 32\-bit file size
350 This is the on\-disk size from stat(2), truncated to 32\-bit\&.
351 .fi
352 .if n \{\
353 .RE
354 .\}
355 .sp
356 .if n \{\
357 .RS 4
358 .\}
359 .nf
360 Object name for the represented object
361 .fi
362 .if n \{\
363 .RE
364 .\}
365 .sp
366 .if n \{\
367 .RS 4
368 .\}
369 .nf
370 A 16\-bit \*(Aqflags\*(Aq field split into (high to low bits)
371 .fi
372 .if n \{\
373 .RE
374 .\}
375 .sp
376 .if n \{\
377 .RS 4
378 .\}
379 .nf
380 1\-bit assume\-valid flag
381 .fi
382 .if n \{\
383 .RE
384 .\}
385 .sp
386 .if n \{\
387 .RS 4
388 .\}
389 .nf
390 1\-bit extended flag (must be zero in version 2)
391 .fi
392 .if n \{\
393 .RE
394 .\}
395 .sp
396 .if n \{\
397 .RS 4
398 .\}
399 .nf
400 2\-bit stage (during merge)
401 .fi
402 .if n \{\
403 .RE
404 .\}
405 .sp
406 .if n \{\
407 .RS 4
408 .\}
409 .nf
410 12\-bit name length if the length is less than 0xFFF; otherwise 0xFFF
411 is stored in this field\&.
412 .fi
413 .if n \{\
414 .RE
415 .\}
416 .sp
417 .if n \{\
418 .RS 4
419 .\}
420 .nf
421 (Version 3 or later) A 16\-bit field, only applicable if the
422 "extended flag" above is 1, split into (high to low bits)\&.
423 .fi
424 .if n \{\
425 .RE
426 .\}
427 .sp
428 .if n \{\
429 .RS 4
430 .\}
431 .nf
432 1\-bit reserved for future
433 .fi
434 .if n \{\
435 .RE
436 .\}
437 .sp
438 .if n \{\
439 .RS 4
440 .\}
441 .nf
442 1\-bit skip\-worktree flag (used by sparse checkout)
443 .fi
444 .if n \{\
445 .RE
446 .\}
447 .sp
448 .if n \{\
449 .RS 4
450 .\}
451 .nf
452 1\-bit intent\-to\-add flag (used by "git add \-N")
453 .fi
454 .if n \{\
455 .RE
456 .\}
457 .sp
458 .if n \{\
459 .RS 4
460 .\}
461 .nf
462 13\-bit unused, must be zero
463 .fi
464 .if n \{\
465 .RE
466 .\}
467 .sp
468 .if n \{\
469 .RS 4
470 .\}
471 .nf
472 Entry path name (variable length) relative to top level directory
473 (without leading slash)\&. \*(Aq/\*(Aq is used as path separator\&. The special
474 path components "\&.", "\&.\&." and "\&.git" (without quotes) are disallowed\&.
475 Trailing slash is also disallowed\&.
476 .fi
477 .if n \{\
478 .RE
479 .\}
480 .sp
481 .if n \{\
482 .RS 4
483 .\}
484 .nf
485 The exact encoding is undefined, but the \*(Aq\&.\*(Aq and \*(Aq/\*(Aq characters
486 are encoded in 7\-bit ASCII and the encoding cannot contain a NUL
487 byte (iow, this is a UNIX pathname)\&.
488 .fi
489 .if n \{\
490 .RE
491 .\}
492 .sp
493 .if n \{\
494 .RS 4
495 .\}
496 .nf
497 (Version 4) In version 4, the entry path name is prefix\-compressed
498 relative to the path name for the previous entry (the very first
499 entry is encoded as if the path name for the previous entry is an
500 empty string)\&. At the beginning of an entry, an integer N in the
501 variable width encoding (the same encoding as the offset is encoded
502 for OFS_DELTA pack entries; see linkgit:gitformat\-pack[5]) is stored, followed
503 by a NUL\-terminated string S\&. Removing N bytes from the end of the
504 path name for the previous entry, and replacing it with the string S
505 yields the path name for this entry\&.
506 .fi
507 .if n \{\
508 .RE
509 .\}
510 .sp
511 .if n \{\
512 .RS 4
513 .\}
514 .nf
515 1\-8 nul bytes as necessary to pad the entry to a multiple of eight bytes
516 while keeping the name NUL\-terminated\&.
517 .fi
518 .if n \{\
519 .RE
520 .\}
521 .sp
522 .if n \{\
523 .RS 4
524 .\}
525 .nf
526 (Version 4) In version 4, the padding after the pathname does not
527 exist\&.
528 .fi
529 .if n \{\
530 .RE
531 .\}
532 .sp
533 .if n \{\
534 .RS 4
535 .\}
536 .nf
537 Interpretation of index entries in split index mode is completely
538 different\&. See below for details\&.
539 .fi
540 .if n \{\
541 .RE
542 .\}
543 .SH "EXTENSIONS"
544 .SS "Cache tree"
545 .sp
546 .if n \{\
547 .RS 4
548 .\}
549 .nf
550 Since the index does not record entries for directories, the cache
551 entries cannot describe tree objects that already exist in the object
552 database for regions of the index that are unchanged from an existing
553 commit\&. The cache tree extension stores a recursive tree structure that
554 describes the trees that already exist and completely match sections of
555 the cache entries\&. This speeds up tree object generation from the index
556 for a new commit by only computing the trees that are "new" to that
557 commit\&. It also assists when comparing the index to another tree, such
558 as `HEAD^{tree}`, since sections of the index can be skipped when a tree
559 comparison demonstrates equality\&.
560 .fi
561 .if n \{\
562 .RE
563 .\}
564 .sp
565 .if n \{\
566 .RS 4
567 .\}
568 .nf
569 The recursive tree structure uses nodes that store a number of cache
570 entries, a list of subnodes, and an object ID (OID)\&. The OID references
571 the existing tree for that node, if it is known to exist\&. The subnodes
572 correspond to subdirectories that themselves have cache tree nodes\&. The
573 number of cache entries corresponds to the number of cache entries in
574 the index that describe paths within that tree\*(Aqs directory\&.
575 .fi
576 .if n \{\
577 .RE
578 .\}
579 .sp
580 .if n \{\
581 .RS 4
582 .\}
583 .nf
584 The extension tracks the full directory structure in the cache tree
585 extension, but this is generally smaller than the full cache entry list\&.
586 .fi
587 .if n \{\
588 .RE
589 .\}
590 .sp
591 .if n \{\
592 .RS 4
593 .\}
594 .nf
595 When a path is updated in index, Git invalidates all nodes of the
596 recursive cache tree corresponding to the parent directories of that
597 path\&. We store these tree nodes as being "invalid" by using "\-1" as the
598 number of cache entries\&. Invalid nodes still store a span of index
599 entries, allowing Git to focus its efforts when reconstructing a full
600 cache tree\&.
601 .fi
602 .if n \{\
603 .RE
604 .\}
605 .sp
606 .if n \{\
607 .RS 4
608 .\}
609 .nf
610 The signature for this extension is { \*(AqT\*(Aq, \*(AqR\*(Aq, \*(AqE\*(Aq, \*(AqE\*(Aq }\&.
611 .fi
612 .if n \{\
613 .RE
614 .\}
615 .sp
616 .if n \{\
617 .RS 4
618 .\}
619 .nf
620 A series of entries fill the entire extension; each of which
621 consists of:
622 .fi
623 .if n \{\
624 .RE
625 .\}
626 .sp
627 .RS 4
628 .ie n \{\
629 \h'-04'\(bu\h'+03'\c
630 .\}
631 .el \{\
632 .sp -1
633 .IP \(bu 2.3
634 .\}
635 NUL\-terminated path component (relative to its parent directory);
636 .RE
637 .sp
638 .RS 4
639 .ie n \{\
640 \h'-04'\(bu\h'+03'\c
641 .\}
642 .el \{\
643 .sp -1
644 .IP \(bu 2.3
645 .\}
646 ASCII decimal number of entries in the index that is covered by the tree this entry represents (entry_count);
647 .RE
648 .sp
649 .RS 4
650 .ie n \{\
651 \h'-04'\(bu\h'+03'\c
652 .\}
653 .el \{\
654 .sp -1
655 .IP \(bu 2.3
656 .\}
657 A space (ASCII 32);
658 .RE
659 .sp
660 .RS 4
661 .ie n \{\
662 \h'-04'\(bu\h'+03'\c
663 .\}
664 .el \{\
665 .sp -1
666 .IP \(bu 2.3
667 .\}
668 ASCII decimal number that represents the number of subtrees this tree has;
669 .RE
670 .sp
671 .RS 4
672 .ie n \{\
673 \h'-04'\(bu\h'+03'\c
674 .\}
675 .el \{\
676 .sp -1
677 .IP \(bu 2.3
678 .\}
679 A newline (ASCII 10); and
680 .RE
681 .sp
682 .RS 4
683 .ie n \{\
684 \h'-04'\(bu\h'+03'\c
685 .\}
686 .el \{\
687 .sp -1
688 .IP \(bu 2.3
689 .\}
690 Object name for the object that would result from writing this span of index as a tree\&.
691 .sp
692 .if n \{\
693 .RS 4
694 .\}
695 .nf
696 An entry can be in an invalidated state and is represented by having
697 a negative number in the entry_count field\&. In this case, there is no
698 object name and the next entry starts immediately after the newline\&.
699 When writing an invalid entry, \-1 should always be used as entry_count\&.
700 .fi
701 .if n \{\
702 .RE
703 .\}
704 .sp
705 .if n \{\
706 .RS 4
707 .\}
708 .nf
709 The entries are written out in the top\-down, depth\-first order\&. The
710 first entry represents the root level of the repository, followed by the
711 first subtree\-\-let\*(Aqs call this A\-\-of the root level (with its name
712 relative to the root level), followed by the first subtree of A (with
713 its name relative to A), and so on\&. The specified number of subtrees
714 indicates when the current level of the recursive stack is complete\&.
715 .fi
716 .if n \{\
717 .RE
718 .\}
719 .RE
720 .SS "Resolve undo"
721 .sp
722 .if n \{\
723 .RS 4
724 .\}
725 .nf
726 A conflict is represented in the index as a set of higher stage entries\&.
727 When a conflict is resolved (e\&.g\&. with "git add path"), these higher
728 stage entries will be removed and a stage\-0 entry with proper resolution
729 is added\&.
730 .fi
731 .if n \{\
732 .RE
733 .\}
734 .sp
735 .if n \{\
736 .RS 4
737 .\}
738 .nf
739 When these higher stage entries are removed, they are saved in the
740 resolve undo extension, so that conflicts can be recreated (e\&.g\&. with
741 "git checkout \-m"), in case users want to redo a conflict resolution
742 from scratch\&.
743 .fi
744 .if n \{\
745 .RE
746 .\}
747 .sp
748 .if n \{\
749 .RS 4
750 .\}
751 .nf
752 The signature for this extension is { \*(AqR\*(Aq, \*(AqE\*(Aq, \*(AqU\*(Aq, \*(AqC\*(Aq }\&.
753 .fi
754 .if n \{\
755 .RE
756 .\}
757 .sp
758 .if n \{\
759 .RS 4
760 .\}
761 .nf
762 A series of entries fill the entire extension; each of which
763 consists of:
764 .fi
765 .if n \{\
766 .RE
767 .\}
768 .sp
769 .RS 4
770 .ie n \{\
771 \h'-04'\(bu\h'+03'\c
772 .\}
773 .el \{\
774 .sp -1
775 .IP \(bu 2.3
776 .\}
777 NUL\-terminated pathname the entry describes (relative to the root of the repository, i\&.e\&. full pathname);
778 .RE
779 .sp
780 .RS 4
781 .ie n \{\
782 \h'-04'\(bu\h'+03'\c
783 .\}
784 .el \{\
785 .sp -1
786 .IP \(bu 2.3
787 .\}
788 Three NUL\-terminated ASCII octal numbers, entry mode of entries in stage 1 to 3 (a missing stage is represented by "0" in this field); and
789 .RE
790 .sp
791 .RS 4
792 .ie n \{\
793 \h'-04'\(bu\h'+03'\c
794 .\}
795 .el \{\
796 .sp -1
797 .IP \(bu 2.3
798 .\}
799 At most three object names of the entry in stages from 1 to 3 (nothing is written for a missing stage)\&.
800 .RE
801 .SS "Split index"
802 .sp
803 .if n \{\
804 .RS 4
805 .\}
806 .nf
807 In split index mode, the majority of index entries could be stored
808 in a separate file\&. This extension records the changes to be made on
809 top of that to produce the final index\&.
810 .fi
811 .if n \{\
812 .RE
813 .\}
814 .sp
815 .if n \{\
816 .RS 4
817 .\}
818 .nf
819 The signature for this extension is { \*(Aql\*(Aq, \*(Aqi\*(Aq, \*(Aqn\*(Aq, \*(Aqk\*(Aq }\&.
820 .fi
821 .if n \{\
822 .RE
823 .\}
824 .sp
825 .if n \{\
826 .RS 4
827 .\}
828 .nf
829 The extension consists of:
830 .fi
831 .if n \{\
832 .RE
833 .\}
834 .sp
835 .RS 4
836 .ie n \{\
837 \h'-04'\(bu\h'+03'\c
838 .\}
839 .el \{\
840 .sp -1
841 .IP \(bu 2.3
842 .\}
843 Hash of the shared index file\&. The shared index file path is $GIT_DIR/sharedindex\&.<hash>\&. If all bits are zero, the index does not require a shared index file\&.
844 .RE
845 .sp
846 .RS 4
847 .ie n \{\
848 \h'-04'\(bu\h'+03'\c
849 .\}
850 .el \{\
851 .sp -1
852 .IP \(bu 2.3
853 .\}
854 An ewah\-encoded delete bitmap, each bit represents an entry in the shared index\&. If a bit is set, its corresponding entry in the shared index will be removed from the final index\&. Note, because a delete operation changes index entry positions, but we do need original positions in replace phase, it\(cqs best to just mark entries for removal, then do a mass deletion after replacement\&.
855 .RE
856 .sp
857 .RS 4
858 .ie n \{\
859 \h'-04'\(bu\h'+03'\c
860 .\}
861 .el \{\
862 .sp -1
863 .IP \(bu 2.3
864 .\}
865 An ewah\-encoded replace bitmap, each bit represents an entry in the shared index\&. If a bit is set, its corresponding entry in the shared index will be replaced with an entry in this index file\&. All replaced entries are stored in sorted order in this index\&. The first "1" bit in the replace bitmap corresponds to the first index entry, the second "1" bit to the second entry and so on\&. Replaced entries may have empty path names to save space\&.
866 .sp
867 .if n \{\
868 .RS 4
869 .\}
870 .nf
871 The remaining index entries after replaced ones will be added to the
872 final index\&. These added entries are also sorted by entry name then
873 stage\&.
874 .fi
875 .if n \{\
876 .RE
877 .\}
878 .RE
879 .SH "UNTRACKED CACHE"
880 .sp
881 .if n \{\
882 .RS 4
883 .\}
884 .nf
885 Untracked cache saves the untracked file list and necessary data to
886 verify the cache\&. The signature for this extension is { \*(AqU\*(Aq, \*(AqN\*(Aq,
887 \*(AqT\*(Aq, \*(AqR\*(Aq }\&.
888 .fi
889 .if n \{\
890 .RE
891 .\}
892 .sp
893 .if n \{\
894 .RS 4
895 .\}
896 .nf
897 The extension starts with
898 .fi
899 .if n \{\
900 .RE
901 .\}
902 .sp
903 .RS 4
904 .ie n \{\
905 \h'-04'\(bu\h'+03'\c
906 .\}
907 .el \{\
908 .sp -1
909 .IP \(bu 2.3
910 .\}
911 A sequence of NUL\-terminated strings, preceded by the size of the sequence in variable width encoding\&. Each string describes the environment where the cache can be used\&.
912 .RE
913 .sp
914 .RS 4
915 .ie n \{\
916 \h'-04'\(bu\h'+03'\c
917 .\}
918 .el \{\
919 .sp -1
920 .IP \(bu 2.3
921 .\}
922 Stat data of $GIT_DIR/info/exclude\&. See "Index entry" section from ctime field until "file size"\&.
923 .RE
924 .sp
925 .RS 4
926 .ie n \{\
927 \h'-04'\(bu\h'+03'\c
928 .\}
929 .el \{\
930 .sp -1
931 .IP \(bu 2.3
932 .\}
933 Stat data of core\&.excludesFile
934 .RE
935 .sp
936 .RS 4
937 .ie n \{\
938 \h'-04'\(bu\h'+03'\c
939 .\}
940 .el \{\
941 .sp -1
942 .IP \(bu 2.3
943 .\}
944 32\-bit dir_flags (see struct dir_struct)
945 .RE
946 .sp
947 .RS 4
948 .ie n \{\
949 \h'-04'\(bu\h'+03'\c
950 .\}
951 .el \{\
952 .sp -1
953 .IP \(bu 2.3
954 .\}
955 Hash of $GIT_DIR/info/exclude\&. A null hash means the file does not exist\&.
956 .RE
957 .sp
958 .RS 4
959 .ie n \{\
960 \h'-04'\(bu\h'+03'\c
961 .\}
962 .el \{\
963 .sp -1
964 .IP \(bu 2.3
965 .\}
966 Hash of core\&.excludesFile\&. A null hash means the file does not exist\&.
967 .RE
968 .sp
969 .RS 4
970 .ie n \{\
971 \h'-04'\(bu\h'+03'\c
972 .\}
973 .el \{\
974 .sp -1
975 .IP \(bu 2.3
976 .\}
977 NUL\-terminated string of per\-dir exclude file name\&. This usually is "\&.gitignore"\&.
978 .RE
979 .sp
980 .RS 4
981 .ie n \{\
982 \h'-04'\(bu\h'+03'\c
983 .\}
984 .el \{\
985 .sp -1
986 .IP \(bu 2.3
987 .\}
988 The number of following directory blocks, variable width encoding\&. If this number is zero, the extension ends here with a following NUL\&.
989 .RE
990 .sp
991 .RS 4
992 .ie n \{\
993 \h'-04'\(bu\h'+03'\c
994 .\}
995 .el \{\
996 .sp -1
997 .IP \(bu 2.3
998 .\}
999 A number of directory blocks in depth\-first\-search order, each consists of
1000 .RE
1001 .sp
1002 .RS 4
1003 .ie n \{\
1004 \h'-04'\(bu\h'+03'\c
1005 .\}
1006 .el \{\
1007 .sp -1
1008 .IP \(bu 2.3
1009 .\}
1010 The number of untracked entries, variable width encoding\&.
1011 .RE
1012 .sp
1013 .RS 4
1014 .ie n \{\
1015 \h'-04'\(bu\h'+03'\c
1016 .\}
1017 .el \{\
1018 .sp -1
1019 .IP \(bu 2.3
1020 .\}
1021 The number of sub\-directory blocks, variable width encoding\&.
1022 .RE
1023 .sp
1024 .RS 4
1025 .ie n \{\
1026 \h'-04'\(bu\h'+03'\c
1027 .\}
1028 .el \{\
1029 .sp -1
1030 .IP \(bu 2.3
1031 .\}
1032 The directory name terminated by NUL\&.
1033 .RE
1034 .sp
1035 .RS 4
1036 .ie n \{\
1037 \h'-04'\(bu\h'+03'\c
1038 .\}
1039 .el \{\
1040 .sp -1
1041 .IP \(bu 2.3
1042 .\}
1043 A number of untracked file/dir names terminated by NUL\&.
1044 .RE
1045 .sp
1046 The remaining data of each directory block is grouped by type:
1047 .sp
1048 .RS 4
1049 .ie n \{\
1050 \h'-04'\(bu\h'+03'\c
1051 .\}
1052 .el \{\
1053 .sp -1
1054 .IP \(bu 2.3
1055 .\}
1056 An ewah bitmap, the n\-th bit marks whether the n\-th directory has valid untracked cache entries\&.
1057 .RE
1058 .sp
1059 .RS 4
1060 .ie n \{\
1061 \h'-04'\(bu\h'+03'\c
1062 .\}
1063 .el \{\
1064 .sp -1
1065 .IP \(bu 2.3
1066 .\}
1067 An ewah bitmap, the n\-th bit records "check\-only" bit of read_directory_recursive() for the n\-th directory\&.
1068 .RE
1069 .sp
1070 .RS 4
1071 .ie n \{\
1072 \h'-04'\(bu\h'+03'\c
1073 .\}
1074 .el \{\
1075 .sp -1
1076 .IP \(bu 2.3
1077 .\}
1078 An ewah bitmap, the n\-th bit indicates whether hash and stat data is valid for the n\-th directory and exists in the next data\&.
1079 .RE
1080 .sp
1081 .RS 4
1082 .ie n \{\
1083 \h'-04'\(bu\h'+03'\c
1084 .\}
1085 .el \{\
1086 .sp -1
1087 .IP \(bu 2.3
1088 .\}
1089 An array of stat data\&. The n\-th data corresponds with the n\-th "one" bit in the previous ewah bitmap\&.
1090 .RE
1091 .sp
1092 .RS 4
1093 .ie n \{\
1094 \h'-04'\(bu\h'+03'\c
1095 .\}
1096 .el \{\
1097 .sp -1
1098 .IP \(bu 2.3
1099 .\}
1100 An array of hashes\&. The n\-th hash corresponds with the n\-th "one" bit in the previous ewah bitmap\&.
1101 .RE
1102 .sp
1103 .RS 4
1104 .ie n \{\
1105 \h'-04'\(bu\h'+03'\c
1106 .\}
1107 .el \{\
1108 .sp -1
1109 .IP \(bu 2.3
1110 .\}
1111 One NUL\&.
1112 .RE
1113 .SH "FILE SYSTEM MONITOR CACHE"
1114 .sp
1115 .if n \{\
1116 .RS 4
1117 .\}
1118 .nf
1119 The file system monitor cache tracks files for which the core\&.fsmonitor
1120 hook has told us about changes\&. The signature for this extension is
1121 { \*(AqF\*(Aq, \*(AqS\*(Aq, \*(AqM\*(Aq, \*(AqN\*(Aq }\&.
1122 .fi
1123 .if n \{\
1124 .RE
1125 .\}
1126 .sp
1127 .if n \{\
1128 .RS 4
1129 .\}
1130 .nf
1131 The extension starts with
1132 .fi
1133 .if n \{\
1134 .RE
1135 .\}
1136 .sp
1137 .RS 4
1138 .ie n \{\
1139 \h'-04'\(bu\h'+03'\c
1140 .\}
1141 .el \{\
1142 .sp -1
1143 .IP \(bu 2.3
1144 .\}
1145 32\-bit version number: the current supported versions are 1 and 2\&.
1146 .RE
1147 .sp
1148 .RS 4
1149 .ie n \{\
1150 \h'-04'\(bu\h'+03'\c
1151 .\}
1152 .el \{\
1153 .sp -1
1154 .IP \(bu 2.3
1155 .\}
1156 (Version 1) 64\-bit time: the extension data reflects all changes through the given time which is stored as the nanoseconds elapsed since midnight, January 1, 1970\&.
1157 .RE
1158 .sp
1159 .RS 4
1160 .ie n \{\
1161 \h'-04'\(bu\h'+03'\c
1162 .\}
1163 .el \{\
1164 .sp -1
1165 .IP \(bu 2.3
1166 .\}
1167 (Version 2) A null terminated string: an opaque token defined by the file system monitor application\&. The extension data reflects all changes relative to that token\&.
1168 .RE
1169 .sp
1170 .RS 4
1171 .ie n \{\
1172 \h'-04'\(bu\h'+03'\c
1173 .\}
1174 .el \{\
1175 .sp -1
1176 .IP \(bu 2.3
1177 .\}
1178 32\-bit bitmap size: the size of the CE_FSMONITOR_VALID bitmap\&.
1179 .RE
1180 .sp
1181 .RS 4
1182 .ie n \{\
1183 \h'-04'\(bu\h'+03'\c
1184 .\}
1185 .el \{\
1186 .sp -1
1187 .IP \(bu 2.3
1188 .\}
1189 An ewah bitmap, the n\-th bit indicates whether the n\-th index entry is not CE_FSMONITOR_VALID\&.
1190 .RE
1191 .SH "END OF INDEX ENTRY"
1192 .sp
1193 .if n \{\
1194 .RS 4
1195 .\}
1196 .nf
1197 The End of Index Entry (EOIE) is used to locate the end of the variable
1198 length index entries and the beginning of the extensions\&. Code can take
1199 advantage of this to quickly locate the index extensions without having
1200 to parse through all of the index entries\&.
1201 .fi
1202 .if n \{\
1203 .RE
1204 .\}
1205 .sp
1206 .if n \{\
1207 .RS 4
1208 .\}
1209 .nf
1210 Because it must be able to be loaded before the variable length cache
1211 entries and other index extensions, this extension must be written last\&.
1212 The signature for this extension is { \*(AqE\*(Aq, \*(AqO\*(Aq, \*(AqI\*(Aq, \*(AqE\*(Aq }\&.
1213 .fi
1214 .if n \{\
1215 .RE
1216 .\}
1217 .sp
1218 .if n \{\
1219 .RS 4
1220 .\}
1221 .nf
1222 The extension consists of:
1223 .fi
1224 .if n \{\
1225 .RE
1226 .\}
1227 .sp
1228 .RS 4
1229 .ie n \{\
1230 \h'-04'\(bu\h'+03'\c
1231 .\}
1232 .el \{\
1233 .sp -1
1234 .IP \(bu 2.3
1235 .\}
1236 32\-bit offset to the end of the index entries
1237 .RE
1238 .sp
1239 .RS 4
1240 .ie n \{\
1241 \h'-04'\(bu\h'+03'\c
1242 .\}
1243 .el \{\
1244 .sp -1
1245 .IP \(bu 2.3
1246 .\}
1247 Hash over the extension types and their sizes (but not their contents)\&. E\&.g\&. if we have "TREE" extension that is N\-bytes long, "REUC" extension that is M\-bytes long, followed by "EOIE", then the hash would be:
1248 .sp
1249 .if n \{\
1250 .RS 4
1251 .\}
1252 .nf
1253 Hash("TREE" + <binary\-representation\-of\-N> +
1254 "REUC" + <binary\-representation\-of\-M>)
1255 .fi
1256 .if n \{\
1257 .RE
1258 .\}
1259 .RE
1260 .SH "INDEX ENTRY OFFSET TABLE"
1261 .sp
1262 .if n \{\
1263 .RS 4
1264 .\}
1265 .nf
1266 The Index Entry Offset Table (IEOT) is used to help address the CPU
1267 cost of loading the index by enabling multi\-threading the process of
1268 converting cache entries from the on\-disk format to the in\-memory format\&.
1269 The signature for this extension is { \*(AqI\*(Aq, \*(AqE\*(Aq, \*(AqO\*(Aq, \*(AqT\*(Aq }\&.
1270 .fi
1271 .if n \{\
1272 .RE
1273 .\}
1274 .sp
1275 .if n \{\
1276 .RS 4
1277 .\}
1278 .nf
1279 The extension consists of:
1280 .fi
1281 .if n \{\
1282 .RE
1283 .\}
1284 .sp
1285 .RS 4
1286 .ie n \{\
1287 \h'-04'\(bu\h'+03'\c
1288 .\}
1289 .el \{\
1290 .sp -1
1291 .IP \(bu 2.3
1292 .\}
1293 32\-bit version (currently 1)
1294 .RE
1295 .sp
1296 .RS 4
1297 .ie n \{\
1298 \h'-04'\(bu\h'+03'\c
1299 .\}
1300 .el \{\
1301 .sp -1
1302 .IP \(bu 2.3
1303 .\}
1304 A number of index offset entries each consisting of:
1305 .RE
1306 .sp
1307 .RS 4
1308 .ie n \{\
1309 \h'-04'\(bu\h'+03'\c
1310 .\}
1311 .el \{\
1312 .sp -1
1313 .IP \(bu 2.3
1314 .\}
1315 32\-bit offset from the beginning of the file to the first cache entry in this block of entries\&.
1316 .RE
1317 .sp
1318 .RS 4
1319 .ie n \{\
1320 \h'-04'\(bu\h'+03'\c
1321 .\}
1322 .el \{\
1323 .sp -1
1324 .IP \(bu 2.3
1325 .\}
1326 32\-bit count of cache entries in this block
1327 .RE
1328 .SH "SPARSE DIRECTORY ENTRIES"
1329 .sp
1330 .if n \{\
1331 .RS 4
1332 .\}
1333 .nf
1334 When using sparse\-checkout in cone mode, some entire directories within
1335 the index can be summarized by pointing to a tree object instead of the
1336 entire expanded list of paths within that tree\&. An index containing such
1337 entries is a "sparse index"\&. Index format versions 4 and less were not
1338 implemented with such entries in mind\&. Thus, for these versions, an
1339 index containing sparse directory entries will include this extension
1340 with signature { \*(Aqs\*(Aq, \*(Aqd\*(Aq, \*(Aqi\*(Aq, \*(Aqr\*(Aq }\&. Like the split\-index extension,
1341 tools should avoid interacting with a sparse index unless they understand
1342 this extension\&.
1343 .fi
1344 .if n \{\
1345 .RE
1346 .\}
1347 .SH "GIT"
1348 .sp
1349 Part of the \fBgit\fR(1) suite