about summary refs log blame commit diff
path: root/dir.c
blob: 0ffb1b3302452c2cce0bdaa55e5259d9be168b63 (plain) (tree)
1
2
3
4
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490



                                                         






































                                                                            

                           







                                                                                 

                                                               




















































































                                                                                   
                                                                     




































































































































                                                                               
                                        

  





                                                                             
  
                                                                           
  

                                                                      
  








                                                                            


































































                                                                              

                                                                                 
                                                              
                                                            
                                           
                                                     
                                                            
                                                                    
 
                                                                       





                                                              






                                                                         







                                                                              
                                                            























































































































                                                                                  
                                                                   






























































                                                                                
                                             








                                              
                                                




                                       
                                                 





                                   
                                             








                                                                   
                                                



                          







































































































































































































                                                                                                 
 


























                                                                  



                          


                                                                         
                

                                                    
         










                                                        



















                                                                                    

                                                                      
   
                                                


              



                                      
 
                                   









































































































                                                                                    
                                                           
                                                                  
                                                             



                                                                     
                         

                                                                  
                                                                    

                                                               

                                                                            




















































                                                                                             

                                                                          




                                                             
                                                               


                 
                                                           
                                                                  
                                                            



                          



                                                                      

                                      
                                          







                                                                     
                                                                              







                                            

                                                                        

                                                              
                                                                    

 
                                   

                                      
                                








                                                 
                                                               


                 
                                                             

                                                                      
                                


                                                     




                                                           




                                                                
                                                                               

                                                               
                                






                                                               

                                                               


                                                                  
                                                                      

                                                                            
                                                   









                                                                   
                                                   















































































                                                                             
                                                                                 


                                                                            
                                                                               

                                                                                  
                                                        

              
                    

                                               



                                                               
 

                                                                                  



                                             
                                                          

                                                                           


                                                                                




                                      

                                                                   
                                                     




                                                                               


                              
                   


  



                                                                
   


























































                                                                                      

 



                                                                   


                                         
                                     


                                                      
                                                                  
                                                                     


                                                       













                                                                 
                                














                                                                      
                                                                
                                               


                                                                      




                                                                            
                         







































                                                                           
                                                           






                                                                                  
                                                                            



                                                                               



                                                                        
























                                                                            
                                                                       
                                                                              
                                                                            




                                                                         

                                                                                




                                                                             

                                                                           





                                                                           
                                                                        


















                                                                        
                                                                  









                                                                 

                                    
 
                                                                               










                                                                      



                                                                      





































































































































                                                                                      

                            








                                                                    










                                                                                

























                                                                                                 






































































































































                                                                          

                                                               
 























                                                                                
                                                    




                                                                                               
                                                                   










































































































                                                                                           
                          

                                                                          
                                                                               

                                     
                                          


                                                          

                                                                              










































                                                                                       
                                                                    










































                                                                          

                          
                         



                                                  
                                  


                                          


































                                                                                     

































                                                                           























                                                                             








                                                                           






















                                                                              




                                                                                                                                    









                                                                                                   





                                                                                 


































                                                                                     


                                                                           




























                                                                                     








                                                                           
                                       

                                           
                       


















                                                                              




                                           


                                       
                    
                    
                   

                                              




                                                      
                                  


                                               























                                                                                                                            
                                                           
                                   
                                                      
         




                                                                     
                            
                                     





















































































































































































































































































































































































                                                                                                
                                          








































                                                                              
                                                            





                                                                                         
                                                           






























                                                                                                
                                




                                                    
                                           
                                          

                                                      
                 
                                










































































































































































































































































































































































































































































































































































                                                                                            
/*
 * This handles recursive filename detection with exclude
 * files, index knowledge etc..
 *
 * Copyright (C) Linus Torvalds, 2005-2006
 *		 Junio Hamano, 2005-2006
 */
#include "cache.h"
#include "config.h"
#include "dir.h"
#include "object-store.h"
#include "attr.h"
#include "refs.h"
#include "wildmatch.h"
#include "pathspec.h"
#include "utf8.h"
#include "varint.h"
#include "ewah/ewok.h"
#include "fsmonitor.h"
#include "submodule-config.h"

/*
 * Tells read_directory_recursive how a file or directory should be treated.
 * Values are ordered by significance, e.g. if a directory contains both
 * excluded and untracked files, it is listed as untracked because
 * path_untracked > path_excluded.
 */
enum path_treatment {
	path_none = 0,
	path_recurse,
	path_excluded,
	path_untracked
};

/*
 * Support data structure for our opendir/readdir/closedir wrappers
 */
struct cached_dir {
	DIR *fdir;
	struct untracked_cache_dir *untracked;
	int nr_files;
	int nr_dirs;

	const char *d_name;
	int d_type;
	const char *file;
	struct untracked_cache_dir *ucd;
};

static enum path_treatment read_directory_recursive(struct dir_struct *dir,
	struct index_state *istate, const char *path, int len,
	struct untracked_cache_dir *untracked,
	int check_only, int stop_at_first_file, const struct pathspec *pathspec);
static int resolve_dtype(int dtype, struct index_state *istate,
			 const char *path, int len);

int count_slashes(const char *s)
{
	int cnt = 0;
	while (*s)
		if (*s++ == '/')
			cnt++;
	return cnt;
}

int fspathcmp(const char *a, const char *b)
{
	return ignore_case ? strcasecmp(a, b) : strcmp(a, b);
}

int fspathncmp(const char *a, const char *b, size_t count)
{
	return ignore_case ? strncasecmp(a, b, count) : strncmp(a, b, count);
}

int git_fnmatch(const struct pathspec_item *item,
		const char *pattern, const char *string,
		int prefix)
{
	if (prefix > 0) {
		if (ps_strncmp(item, pattern, string, prefix))
			return WM_NOMATCH;
		pattern += prefix;
		string += prefix;
	}
	if (item->flags & PATHSPEC_ONESTAR) {
		int pattern_len = strlen(++pattern);
		int string_len = strlen(string);
		return string_len < pattern_len ||
			ps_strcmp(item, pattern,
				  string + string_len - pattern_len);
	}
	if (item->magic & PATHSPEC_GLOB)
		return wildmatch(pattern, string,
				 WM_PATHNAME |
				 (item->magic & PATHSPEC_ICASE ? WM_CASEFOLD : 0));
	else
		/* wildmatch has not learned no FNM_PATHNAME mode yet */
		return wildmatch(pattern, string,
				 item->magic & PATHSPEC_ICASE ? WM_CASEFOLD : 0);
}

static int fnmatch_icase_mem(const char *pattern, int patternlen,
			     const char *string, int stringlen,
			     int flags)
{
	int match_status;
	struct strbuf pat_buf = STRBUF_INIT;
	struct strbuf str_buf = STRBUF_INIT;
	const char *use_pat = pattern;
	const char *use_str = string;

	if (pattern[patternlen]) {
		strbuf_add(&pat_buf, pattern, patternlen);
		use_pat = pat_buf.buf;
	}
	if (string[stringlen]) {
		strbuf_add(&str_buf, string, stringlen);
		use_str = str_buf.buf;
	}

	if (ignore_case)
		flags |= WM_CASEFOLD;
	match_status = wildmatch(use_pat, use_str, flags);

	strbuf_release(&pat_buf);
	strbuf_release(&str_buf);

	return match_status;
}

static size_t common_prefix_len(const struct pathspec *pathspec)
{
	int n;
	size_t max = 0;

	/*
	 * ":(icase)path" is treated as a pathspec full of
	 * wildcard. In other words, only prefix is considered common
	 * prefix. If the pathspec is abc/foo abc/bar, running in
	 * subdir xyz, the common prefix is still xyz, not xyz/abc as
	 * in non-:(icase).
	 */
	GUARD_PATHSPEC(pathspec,
		       PATHSPEC_FROMTOP |
		       PATHSPEC_MAXDEPTH |
		       PATHSPEC_LITERAL |
		       PATHSPEC_GLOB |
		       PATHSPEC_ICASE |
		       PATHSPEC_EXCLUDE |
		       PATHSPEC_ATTR);

	for (n = 0; n < pathspec->nr; n++) {
		size_t i = 0, len = 0, item_len;
		if (pathspec->items[n].magic & PATHSPEC_EXCLUDE)
			continue;
		if (pathspec->items[n].magic & PATHSPEC_ICASE)
			item_len = pathspec->items[n].prefix;
		else
			item_len = pathspec->items[n].nowildcard_len;
		while (i < item_len && (n == 0 || i < max)) {
			char c = pathspec->items[n].match[i];
			if (c != pathspec->items[0].match[i])
				break;
			if (c == '/')
				len = i + 1;
			i++;
		}
		if (n == 0 || len < max) {
			max = len;
			if (!max)
				break;
		}
	}
	return max;
}

/*
 * Returns a copy of the longest leading path common among all
 * pathspecs.
 */
char *common_prefix(const struct pathspec *pathspec)
{
	unsigned long len = common_prefix_len(pathspec);

	return len ? xmemdupz(pathspec->items[0].match, len) : NULL;
}

int fill_directory(struct dir_struct *dir,
		   struct index_state *istate,
		   const struct pathspec *pathspec)
{
	const char *prefix;
	size_t prefix_len;

	/*
	 * Calculate common prefix for the pathspec, and
	 * use that to optimize the directory walk
	 */
	prefix_len = common_prefix_len(pathspec);
	prefix = prefix_len ? pathspec->items[0].match : "";

	/* Read the directory and prune it */
	read_directory(dir, istate, prefix, prefix_len, pathspec);

	return prefix_len;
}

int within_depth(const char *name, int namelen,
			int depth, int max_depth)
{
	const char *cp = name, *cpe = name + namelen;

	while (cp < cpe) {
		if (*cp++ != '/')
			continue;
		depth++;
		if (depth > max_depth)
			return 0;
	}
	return 1;
}

/*
 * Read the contents of the blob with the given OID into a buffer.
 * Append a trailing LF to the end if the last line doesn't have one.
 *
 * Returns:
 *    -1 when the OID is invalid or unknown or does not refer to a blob.
 *     0 when the blob is empty.
 *     1 along with { data, size } of the (possibly augmented) buffer
 *       when successful.
 *
 * Optionally updates the given oid_stat with the given OID (when valid).
 */
static int do_read_blob(const struct object_id *oid, struct oid_stat *oid_stat,
			size_t *size_out, char **data_out)
{
	enum object_type type;
	unsigned long sz;
	char *data;

	*size_out = 0;
	*data_out = NULL;

	data = read_object_file(oid, &type, &sz);
	if (!data || type != OBJ_BLOB) {
		free(data);
		return -1;
	}

	if (oid_stat) {
		memset(&oid_stat->stat, 0, sizeof(oid_stat->stat));
		oidcpy(&oid_stat->oid, oid);
	}

	if (sz == 0) {
		free(data);
		return 0;
	}

	if (data[sz - 1] != '\n') {
		data = xrealloc(data, st_add(sz, 1));
		data[sz++] = '\n';
	}

	*size_out = xsize_t(sz);
	*data_out = data;

	return 1;
}

#define DO_MATCH_EXCLUDE   (1<<0)
#define DO_MATCH_DIRECTORY (1<<1)
#define DO_MATCH_LEADING_PATHSPEC (1<<2)

/*
 * Does the given pathspec match the given name?  A match is found if
 *
 * (1) the pathspec string is leading directory of 'name' ("RECURSIVELY"), or
 * (2) the pathspec string has a leading part matching 'name' ("LEADING"), or
 * (3) the pathspec string is a wildcard and matches 'name' ("WILDCARD"), or
 * (4) the pathspec string is exactly the same as 'name' ("EXACT").
 *
 * Return value tells which case it was (1-4), or 0 when there is no match.
 *
 * It may be instructive to look at a small table of concrete examples
 * to understand the differences between 1, 2, and 4:
 *
 *                              Pathspecs
 *                |    a/b    |   a/b/    |   a/b/c
 *          ------+-----------+-----------+------------
 *          a/b   |  EXACT    |  EXACT[1] | LEADING[2]
 *  Names   a/b/  | RECURSIVE |   EXACT   | LEADING[2]
 *          a/b/c | RECURSIVE | RECURSIVE |   EXACT
 *
 * [1] Only if DO_MATCH_DIRECTORY is passed; otherwise, this is NOT a match.
 * [2] Only if DO_MATCH_LEADING_PATHSPEC is passed; otherwise, not a match.
 */
static int match_pathspec_item(const struct index_state *istate,
			       const struct pathspec_item *item, int prefix,
			       const char *name, int namelen, unsigned flags)
{
	/* name/namelen has prefix cut off by caller */
	const char *match = item->match + prefix;
	int matchlen = item->len - prefix;

	/*
	 * The normal call pattern is:
	 * 1. prefix = common_prefix_len(ps);
	 * 2. prune something, or fill_directory
	 * 3. match_pathspec()
	 *
	 * 'prefix' at #1 may be shorter than the command's prefix and
	 * it's ok for #2 to match extra files. Those extras will be
	 * trimmed at #3.
	 *
	 * Suppose the pathspec is 'foo' and '../bar' running from
	 * subdir 'xyz'. The common prefix at #1 will be empty, thanks
	 * to "../". We may have xyz/foo _and_ XYZ/foo after #2. The
	 * user does not want XYZ/foo, only the "foo" part should be
	 * case-insensitive. We need to filter out XYZ/foo here. In
	 * other words, we do not trust the caller on comparing the
	 * prefix part when :(icase) is involved. We do exact
	 * comparison ourselves.
	 *
	 * Normally the caller (common_prefix_len() in fact) does
	 * _exact_ matching on name[-prefix+1..-1] and we do not need
	 * to check that part. Be defensive and check it anyway, in
	 * case common_prefix_len is changed, or a new caller is
	 * introduced that does not use common_prefix_len.
	 *
	 * If the penalty turns out too high when prefix is really
	 * long, maybe change it to
	 * strncmp(match, name, item->prefix - prefix)
	 */
	if (item->prefix && (item->magic & PATHSPEC_ICASE) &&
	    strncmp(item->match, name - prefix, item->prefix))
		return 0;

	if (item->attr_match_nr &&
	    !match_pathspec_attrs(istate, name, namelen, item))
		return 0;

	/* If the match was just the prefix, we matched */
	if (!*match)
		return MATCHED_RECURSIVELY;

	if (matchlen <= namelen && !ps_strncmp(item, match, name, matchlen)) {
		if (matchlen == namelen)
			return MATCHED_EXACTLY;

		if (match[matchlen-1] == '/' || name[matchlen] == '/')
			return MATCHED_RECURSIVELY;
	} else if ((flags & DO_MATCH_DIRECTORY) &&
		   match[matchlen - 1] == '/' &&
		   namelen == matchlen - 1 &&
		   !ps_strncmp(item, match, name, namelen))
		return MATCHED_EXACTLY;

	if (item->nowildcard_len < item->len &&
	    !git_fnmatch(item, match, name,
			 item->nowildcard_len - prefix))
		return MATCHED_FNMATCH;

	/* Perform checks to see if "name" is a leading string of the pathspec */
	if (flags & DO_MATCH_LEADING_PATHSPEC) {
		/* name is a literal prefix of the pathspec */
		int offset = name[namelen-1] == '/' ? 1 : 0;
		if ((namelen < matchlen) &&
		    (match[namelen-offset] == '/') &&
		    !ps_strncmp(item, match, name, namelen))
			return MATCHED_RECURSIVELY_LEADING_PATHSPEC;

		/* name doesn't match up to the first wild character */
		if (item->nowildcard_len < item->len &&
		    ps_strncmp(item, match, name,
			       item->nowildcard_len - prefix))
			return 0;

		/*
		 * name has no wildcard, and it didn't match as a leading
		 * pathspec so return.
		 */
		if (item->nowildcard_len == item->len)
			return 0;

		/*
		 * Here is where we would perform a wildmatch to check if
		 * "name" can be matched as a directory (or a prefix) against
		 * the pathspec.  Since wildmatch doesn't have this capability
		 * at the present we have to punt and say that it is a match,
		 * potentially returning a false positive
		 * The submodules themselves will be able to perform more
		 * accurate matching to determine if the pathspec matches.
		 */
		return MATCHED_RECURSIVELY_LEADING_PATHSPEC;
	}

	return 0;
}

/*
 * Given a name and a list of pathspecs, returns the nature of the
 * closest (i.e. most specific) match of the name to any of the
 * pathspecs.
 *
 * The caller typically calls this multiple times with the same
 * pathspec and seen[] array but with different name/namelen
 * (e.g. entries from the index) and is interested in seeing if and
 * how each pathspec matches all the names it calls this function
 * with.  A mark is left in the seen[] array for each pathspec element
 * indicating the closest type of match that element achieved, so if
 * seen[n] remains zero after multiple invocations, that means the nth
 * pathspec did not match any names, which could indicate that the
 * user mistyped the nth pathspec.
 */
static int do_match_pathspec(const struct index_state *istate,
			     const struct pathspec *ps,
			     const char *name, int namelen,
			     int prefix, char *seen,
			     unsigned flags)
{
	int i, retval = 0, exclude = flags & DO_MATCH_EXCLUDE;

	GUARD_PATHSPEC(ps,
		       PATHSPEC_FROMTOP |
		       PATHSPEC_MAXDEPTH |
		       PATHSPEC_LITERAL |
		       PATHSPEC_GLOB |
		       PATHSPEC_ICASE |
		       PATHSPEC_EXCLUDE |
		       PATHSPEC_ATTR);

	if (!ps->nr) {
		if (!ps->recursive ||
		    !(ps->magic & PATHSPEC_MAXDEPTH) ||
		    ps->max_depth == -1)
			return MATCHED_RECURSIVELY;

		if (within_depth(name, namelen, 0, ps->max_depth))
			return MATCHED_EXACTLY;
		else
			return 0;
	}

	name += prefix;
	namelen -= prefix;

	for (i = ps->nr - 1; i >= 0; i--) {
		int how;

		if ((!exclude &&   ps->items[i].magic & PATHSPEC_EXCLUDE) ||
		    ( exclude && !(ps->items[i].magic & PATHSPEC_EXCLUDE)))
			continue;

		if (seen && seen[i] == MATCHED_EXACTLY)
			continue;
		/*
		 * Make exclude patterns optional and never report
		 * "pathspec ':(exclude)foo' matches no files"
		 */
		if (seen && ps->items[i].magic & PATHSPEC_EXCLUDE)
			seen[i] = MATCHED_FNMATCH;
		how = match_pathspec_item(istate, ps->items+i, prefix, name,
					  namelen, flags);
		if (ps->recursive &&
		    (ps->magic & PATHSPEC_MAXDEPTH) &&
		    ps->max_depth != -1 &&
		    how && how != MATCHED_FNMATCH) {
			int len = ps->items[i].len;
			if (name[len] == '/')
				len++;
			if (within_depth(name+len, namelen-len, 0, ps->max_depth))
				how = MATCHED_EXACTLY;
			else
				how = 0;
		}
		if (how) {
			if (retval < how)
				retval = how;
			if (seen && seen[i] < how)
				seen[i] = how;
		}
	}
	return retval;
}

int match_pathspec(const struct index_state *istate,
		   const struct pathspec *ps,
		   const char *name, int namelen,
		   int prefix, char *seen, int is_dir)
{
	int positive, negative;
	unsigned flags = is_dir ? DO_MATCH_DIRECTORY : 0;
	positive = do_match_pathspec(istate, ps, name, namelen,
				     prefix, seen, flags);
	if (!(ps->magic & PATHSPEC_EXCLUDE) || !positive)
		return positive;
	negative = do_match_pathspec(istate, ps, name, namelen,
				     prefix, seen,
				     flags | DO_MATCH_EXCLUDE);
	return negative ? 0 : positive;
}

/**
 * Check if a submodule is a superset of the pathspec
 */
int submodule_path_match(const struct index_state *istate,
			 const struct pathspec *ps,
			 const char *submodule_name,
			 char *seen)
{
	int matched = do_match_pathspec(istate, ps, submodule_name,
					strlen(submodule_name),
					0, seen,
					DO_MATCH_DIRECTORY |
					DO_MATCH_LEADING_PATHSPEC);
	return matched;
}

int report_path_error(const char *ps_matched,
		      const struct pathspec *pathspec)
{
	/*
	 * Make sure all pathspec matched; otherwise it is an error.
	 */
	int num, errors = 0;
	for (num = 0; num < pathspec->nr; num++) {
		int other, found_dup;

		if (ps_matched[num])
			continue;
		/*
		 * The caller might have fed identical pathspec
		 * twice.  Do not barf on such a mistake.
		 * FIXME: parse_pathspec should have eliminated
		 * duplicate pathspec.
		 */
		for (found_dup = other = 0;
		     !found_dup && other < pathspec->nr;
		     other++) {
			if (other == num || !ps_matched[other])
				continue;
			if (!strcmp(pathspec->items[other].original,
				    pathspec->items[num].original))
				/*
				 * Ok, we have a match already.
				 */
				found_dup = 1;
		}
		if (found_dup)
			continue;

		error(_("pathspec '%s' did not match any file(s) known to git"),
		      pathspec->items[num].original);
		errors++;
	}
	return errors;
}

/*
 * Return the length of the "simple" part of a path match limiter.
 */
int simple_length(const char *match)
{
	int len = -1;

	for (;;) {
		unsigned char c = *match++;
		len++;
		if (c == '\0' || is_glob_special(c))
			return len;
	}
}

int no_wildcard(const char *string)
{
	return string[simple_length(string)] == '\0';
}

void parse_path_pattern(const char **pattern,
			   int *patternlen,
			   unsigned *flags,
			   int *nowildcardlen)
{
	const char *p = *pattern;
	size_t i, len;

	*flags = 0;
	if (*p == '!') {
		*flags |= PATTERN_FLAG_NEGATIVE;
		p++;
	}
	len = strlen(p);
	if (len && p[len - 1] == '/') {
		len--;
		*flags |= PATTERN_FLAG_MUSTBEDIR;
	}
	for (i = 0; i < len; i++) {
		if (p[i] == '/')
			break;
	}
	if (i == len)
		*flags |= PATTERN_FLAG_NODIR;
	*nowildcardlen = simple_length(p);
	/*
	 * we should have excluded the trailing slash from 'p' too,
	 * but that's one more allocation. Instead just make sure
	 * nowildcardlen does not exceed real patternlen
	 */
	if (*nowildcardlen > len)
		*nowildcardlen = len;
	if (*p == '*' && no_wildcard(p + 1))
		*flags |= PATTERN_FLAG_ENDSWITH;
	*pattern = p;
	*patternlen = len;
}

int pl_hashmap_cmp(const void *unused_cmp_data,
		   const struct hashmap_entry *a,
		   const struct hashmap_entry *b,
		   const void *key)
{
	const struct pattern_entry *ee1 =
			container_of(a, struct pattern_entry, ent);
	const struct pattern_entry *ee2 =
			container_of(b, struct pattern_entry, ent);

	size_t min_len = ee1->patternlen <= ee2->patternlen
			 ? ee1->patternlen
			 : ee2->patternlen;

	if (ignore_case)
		return strncasecmp(ee1->pattern, ee2->pattern, min_len);
	return strncmp(ee1->pattern, ee2->pattern, min_len);
}

static char *dup_and_filter_pattern(const char *pattern)
{
	char *set, *read;
	size_t count  = 0;
	char *result = xstrdup(pattern);

	set = result;
	read = result;

	while (*read) {
		/* skip escape characters (once) */
		if (*read == '\\')
			read++;

		*set = *read;

		set++;
		read++;
		count++;
	}
	*set = 0;

	if (count > 2 &&
	    *(set - 1) == '*' &&
	    *(set - 2) == '/')
		*(set - 2) = 0;

	return result;
}

static void add_pattern_to_hashsets(struct pattern_list *pl, struct path_pattern *given)
{
	struct pattern_entry *translated;
	char *truncated;
	char *data = NULL;
	const char *prev, *cur, *next;

	if (!pl->use_cone_patterns)
		return;

	if (given->flags & PATTERN_FLAG_NEGATIVE &&
	    given->flags & PATTERN_FLAG_MUSTBEDIR &&
	    !strcmp(given->pattern, "/*")) {
		pl->full_cone = 0;
		return;
	}

	if (!given->flags && !strcmp(given->pattern, "/*")) {
		pl->full_cone = 1;
		return;
	}

	if (given->patternlen < 2 ||
	    *given->pattern == '*' ||
	    strstr(given->pattern, "**")) {
		/* Not a cone pattern. */
		warning(_("unrecognized pattern: '%s'"), given->pattern);
		goto clear_hashmaps;
	}

	prev = given->pattern;
	cur = given->pattern + 1;
	next = given->pattern + 2;

	while (*cur) {
		/* Watch for glob characters '*', '\', '[', '?' */
		if (!is_glob_special(*cur))
			goto increment;

		/* But only if *prev != '\\' */
		if (*prev == '\\')
			goto increment;

		/* But allow the initial '\' */
		if (*cur == '\\' &&
		    is_glob_special(*next))
			goto increment;

		/* But a trailing '/' then '*' is fine */
		if (*prev == '/' &&
		    *cur == '*' &&
		    *next == 0)
			goto increment;

		/* Not a cone pattern. */
		warning(_("unrecognized pattern: '%s'"), given->pattern);
		goto clear_hashmaps;

	increment:
		prev++;
		cur++;
		next++;
	}

	if (given->patternlen > 2 &&
	    !strcmp(given->pattern + given->patternlen - 2, "/*")) {
		if (!(given->flags & PATTERN_FLAG_NEGATIVE)) {
			/* Not a cone pattern. */
			warning(_("unrecognized pattern: '%s'"), given->pattern);
			goto clear_hashmaps;
		}

		truncated = dup_and_filter_pattern(given->pattern);

		translated = xmalloc(sizeof(struct pattern_entry));
		translated->pattern = truncated;
		translated->patternlen = given->patternlen - 2;
		hashmap_entry_init(&translated->ent,
				   ignore_case ?
				   strihash(translated->pattern) :
				   strhash(translated->pattern));

		if (!hashmap_get_entry(&pl->recursive_hashmap,
				       translated, ent, NULL)) {
			/* We did not see the "parent" included */
			warning(_("unrecognized negative pattern: '%s'"),
				given->pattern);
			free(truncated);
			free(translated);
			goto clear_hashmaps;
		}

		hashmap_add(&pl->parent_hashmap, &translated->ent);
		hashmap_remove(&pl->recursive_hashmap, &translated->ent, &data);
		free(data);
		return;
	}

	if (given->flags & PATTERN_FLAG_NEGATIVE) {
		warning(_("unrecognized negative pattern: '%s'"),
			given->pattern);
		goto clear_hashmaps;
	}

	translated = xmalloc(sizeof(struct pattern_entry));

	translated->pattern = dup_and_filter_pattern(given->pattern);
	translated->patternlen = given->patternlen;
	hashmap_entry_init(&translated->ent,
			   ignore_case ?
			   strihash(translated->pattern) :
			   strhash(translated->pattern));

	hashmap_add(&pl->recursive_hashmap, &translated->ent);

	if (hashmap_get_entry(&pl->parent_hashmap, translated, ent, NULL)) {
		/* we already included this at the parent level */
		warning(_("your sparse-checkout file may have issues: pattern '%s' is repeated"),
			given->pattern);
		hashmap_remove(&pl->parent_hashmap, &translated->ent, &data);
		free(data);
		free(translated);
	}

	return;

clear_hashmaps:
	warning(_("disabling cone pattern matching"));
	hashmap_free_entries(&pl->parent_hashmap, struct pattern_entry, ent);
	hashmap_free_entries(&pl->recursive_hashmap, struct pattern_entry, ent);
	pl->use_cone_patterns = 0;
}

static int hashmap_contains_path(struct hashmap *map,
				 struct strbuf *pattern)
{
	struct pattern_entry p;

	/* Check straight mapping */
	p.pattern = pattern->buf;
	p.patternlen = pattern->len;
	hashmap_entry_init(&p.ent,
			   ignore_case ?
			   strihash(p.pattern) :
			   strhash(p.pattern));
	return !!hashmap_get_entry(map, &p, ent, NULL);
}

int hashmap_contains_parent(struct hashmap *map,
			    const char *path,
			    struct strbuf *buffer)
{
	char *slash_pos;

	strbuf_setlen(buffer, 0);

	if (path[0] != '/')
		strbuf_addch(buffer, '/');

	strbuf_addstr(buffer, path);

	slash_pos = strrchr(buffer->buf, '/');

	while (slash_pos > buffer->buf) {
		strbuf_setlen(buffer, slash_pos - buffer->buf);

		if (hashmap_contains_path(map, buffer))
			return 1;

		slash_pos = strrchr(buffer->buf, '/');
	}

	return 0;
}

void add_pattern(const char *string, const char *base,
		 int baselen, struct pattern_list *pl, int srcpos)
{
	struct path_pattern *pattern;
	int patternlen;
	unsigned flags;
	int nowildcardlen;

	parse_path_pattern(&string, &patternlen, &flags, &nowildcardlen);
	if (flags & PATTERN_FLAG_MUSTBEDIR) {
		FLEXPTR_ALLOC_MEM(pattern, pattern, string, patternlen);
	} else {
		pattern = xmalloc(sizeof(*pattern));
		pattern->pattern = string;
	}
	pattern->patternlen = patternlen;
	pattern->nowildcardlen = nowildcardlen;
	pattern->base = base;
	pattern->baselen = baselen;
	pattern->flags = flags;
	pattern->srcpos = srcpos;
	ALLOC_GROW(pl->patterns, pl->nr + 1, pl->alloc);
	pl->patterns[pl->nr++] = pattern;
	pattern->pl = pl;

	add_pattern_to_hashsets(pl, pattern);
}

static int read_skip_worktree_file_from_index(const struct index_state *istate,
					      const char *path,
					      size_t *size_out, char **data_out,
					      struct oid_stat *oid_stat)
{
	int pos, len;

	len = strlen(path);
	pos = index_name_pos(istate, path, len);
	if (pos < 0)
		return -1;
	if (!ce_skip_worktree(istate->cache[pos]))
		return -1;

	return do_read_blob(&istate->cache[pos]->oid, oid_stat, size_out, data_out);
}

/*
 * Frees memory within pl which was allocated for exclude patterns and
 * the file buffer.  Does not free pl itself.
 */
void clear_pattern_list(struct pattern_list *pl)
{
	int i;

	for (i = 0; i < pl->nr; i++)
		free(pl->patterns[i]);
	free(pl->patterns);
	free(pl->filebuf);

	memset(pl, 0, sizeof(*pl));
}

static void trim_trailing_spaces(char *buf)
{
	char *p, *last_space = NULL;

	for (p = buf; *p; p++)
		switch (*p) {
		case ' ':
			if (!last_space)
				last_space = p;
			break;
		case '\\':
			p++;
			if (!*p)
				return;
			/* fallthrough */
		default:
			last_space = NULL;
		}

	if (last_space)
		*last_space = '\0';
}

/*
 * Given a subdirectory name and "dir" of the current directory,
 * search the subdir in "dir" and return it, or create a new one if it
 * does not exist in "dir".
 *
 * If "name" has the trailing slash, it'll be excluded in the search.
 */
static struct untracked_cache_dir *lookup_untracked(struct untracked_cache *uc,
						    struct untracked_cache_dir *dir,
						    const char *name, int len)
{
	int first, last;
	struct untracked_cache_dir *d;
	if (!dir)
		return NULL;
	if (len && name[len - 1] == '/')
		len--;
	first = 0;
	last = dir->dirs_nr;
	while (last > first) {
		int cmp, next = first + ((last - first) >> 1);
		d = dir->dirs[next];
		cmp = strncmp(name, d->name, len);
		if (!cmp && strlen(d->name) > len)
			cmp = -1;
		if (!cmp)
			return d;
		if (cmp < 0) {
			last = next;
			continue;
		}
		first = next+1;
	}

	uc->dir_created++;
	FLEX_ALLOC_MEM(d, name, name, len);

	ALLOC_GROW(dir->dirs, dir->dirs_nr + 1, dir->dirs_alloc);
	MOVE_ARRAY(dir->dirs + first + 1, dir->dirs + first,
		   dir->dirs_nr - first);
	dir->dirs_nr++;
	dir->dirs[first] = d;
	return d;
}

static void do_invalidate_gitignore(struct untracked_cache_dir *dir)
{
	int i;
	dir->valid = 0;
	dir->untracked_nr = 0;
	for (i = 0; i < dir->dirs_nr; i++)
		do_invalidate_gitignore(dir->dirs[i]);
}

static void invalidate_gitignore(struct untracked_cache *uc,
				 struct untracked_cache_dir *dir)
{
	uc->gitignore_invalidated++;
	do_invalidate_gitignore(dir);
}

static void invalidate_directory(struct untracked_cache *uc,
				 struct untracked_cache_dir *dir)
{
	int i;

	/*
	 * Invalidation increment here is just roughly correct. If
	 * untracked_nr or any of dirs[].recurse is non-zero, we
	 * should increment dir_invalidated too. But that's more
	 * expensive to do.
	 */
	if (dir->valid)
		uc->dir_invalidated++;

	dir->valid = 0;
	dir->untracked_nr = 0;
	for (i = 0; i < dir->dirs_nr; i++)
		dir->dirs[i]->recurse = 0;
}

static int add_patterns_from_buffer(char *buf, size_t size,
				    const char *base, int baselen,
				    struct pattern_list *pl);

/*
 * Given a file with name "fname", read it (either from disk, or from
 * an index if 'istate' is non-null), parse it and store the
 * exclude rules in "pl".
 *
 * If "ss" is not NULL, compute SHA-1 of the exclude file and fill
 * stat data from disk (only valid if add_patterns returns zero). If
 * ss_valid is non-zero, "ss" must contain good value as input.
 */
static int add_patterns(const char *fname, const char *base, int baselen,
			struct pattern_list *pl, struct index_state *istate,
			struct oid_stat *oid_stat)
{
	struct stat st;
	int r;
	int fd;
	size_t size = 0;
	char *buf;

	fd = open(fname, O_RDONLY);
	if (fd < 0 || fstat(fd, &st) < 0) {
		if (fd < 0)
			warn_on_fopen_errors(fname);
		else
			close(fd);
		if (!istate)
			return -1;
		r = read_skip_worktree_file_from_index(istate, fname,
						       &size, &buf,
						       oid_stat);
		if (r != 1)
			return r;
	} else {
		size = xsize_t(st.st_size);
		if (size == 0) {
			if (oid_stat) {
				fill_stat_data(&oid_stat->stat, &st);
				oidcpy(&oid_stat->oid, the_hash_algo->empty_blob);
				oid_stat->valid = 1;
			}
			close(fd);
			return 0;
		}
		buf = xmallocz(size);
		if (read_in_full(fd, buf, size) != size) {
			free(buf);
			close(fd);
			return -1;
		}
		buf[size++] = '\n';
		close(fd);
		if (oid_stat) {
			int pos;
			if (oid_stat->valid &&
			    !match_stat_data_racy(istate, &oid_stat->stat, &st))
				; /* no content change, ss->sha1 still good */
			else if (istate &&
				 (pos = index_name_pos(istate, fname, strlen(fname))) >= 0 &&
				 !ce_stage(istate->cache[pos]) &&
				 ce_uptodate(istate->cache[pos]) &&
				 !would_convert_to_git(istate, fname))
				oidcpy(&oid_stat->oid,
				       &istate->cache[pos]->oid);
			else
				hash_object_file(the_hash_algo, buf, size,
						 "blob", &oid_stat->oid);
			fill_stat_data(&oid_stat->stat, &st);
			oid_stat->valid = 1;
		}
	}

	add_patterns_from_buffer(buf, size, base, baselen, pl);
	return 0;
}

static int add_patterns_from_buffer(char *buf, size_t size,
				    const char *base, int baselen,
				    struct pattern_list *pl)
{
	int i, lineno = 1;
	char *entry;

	hashmap_init(&pl->recursive_hashmap, pl_hashmap_cmp, NULL, 0);
	hashmap_init(&pl->parent_hashmap, pl_hashmap_cmp, NULL, 0);

	pl->filebuf = buf;

	if (skip_utf8_bom(&buf, size))
		size -= buf - pl->filebuf;

	entry = buf;

	for (i = 0; i < size; i++) {
		if (buf[i] == '\n') {
			if (entry != buf + i && entry[0] != '#') {
				buf[i - (i && buf[i-1] == '\r')] = 0;
				trim_trailing_spaces(entry);
				add_pattern(entry, base, baselen, pl, lineno);
			}
			lineno++;
			entry = buf + i + 1;
		}
	}
	return 0;
}

int add_patterns_from_file_to_list(const char *fname, const char *base,
				   int baselen, struct pattern_list *pl,
				   struct index_state *istate)
{
	return add_patterns(fname, base, baselen, pl, istate, NULL);
}

int add_patterns_from_blob_to_list(
	struct object_id *oid,
	const char *base, int baselen,
	struct pattern_list *pl)
{
	char *buf;
	size_t size;
	int r;

	r = do_read_blob(oid, NULL, &size, &buf);
	if (r != 1)
		return r;

	add_patterns_from_buffer(buf, size, base, baselen, pl);
	return 0;
}

struct pattern_list *add_pattern_list(struct dir_struct *dir,
				      int group_type, const char *src)
{
	struct pattern_list *pl;
	struct exclude_list_group *group;

	group = &dir->exclude_list_group[group_type];
	ALLOC_GROW(group->pl, group->nr + 1, group->alloc);
	pl = &group->pl[group->nr++];
	memset(pl, 0, sizeof(*pl));
	pl->src = src;
	return pl;
}

/*
 * Used to set up core.excludesfile and .git/info/exclude lists.
 */
static void add_patterns_from_file_1(struct dir_struct *dir, const char *fname,
				     struct oid_stat *oid_stat)
{
	struct pattern_list *pl;
	/*
	 * catch setup_standard_excludes() that's called before
	 * dir->untracked is assigned. That function behaves
	 * differently when dir->untracked is non-NULL.
	 */
	if (!dir->untracked)
		dir->unmanaged_exclude_files++;
	pl = add_pattern_list(dir, EXC_FILE, fname);
	if (add_patterns(fname, "", 0, pl, NULL, oid_stat) < 0)
		die(_("cannot use %s as an exclude file"), fname);
}

void add_patterns_from_file(struct dir_struct *dir, const char *fname)
{
	dir->unmanaged_exclude_files++; /* see validate_untracked_cache() */
	add_patterns_from_file_1(dir, fname, NULL);
}

int match_basename(const char *basename, int basenamelen,
		   const char *pattern, int prefix, int patternlen,
		   unsigned flags)
{
	if (prefix == patternlen) {
		if (patternlen == basenamelen &&
		    !fspathncmp(pattern, basename, basenamelen))
			return 1;
	} else if (flags & PATTERN_FLAG_ENDSWITH) {
		/* "*literal" matching against "fooliteral" */
		if (patternlen - 1 <= basenamelen &&
		    !fspathncmp(pattern + 1,
				   basename + basenamelen - (patternlen - 1),
				   patternlen - 1))
			return 1;
	} else {
		if (fnmatch_icase_mem(pattern, patternlen,
				      basename, basenamelen,
				      0) == 0)
			return 1;
	}
	return 0;
}

int match_pathname(const char *pathname, int pathlen,
		   const char *base, int baselen,
		   const char *pattern, int prefix, int patternlen,
		   unsigned flags)
{
	const char *name;
	int namelen;

	/*
	 * match with FNM_PATHNAME; the pattern has base implicitly
	 * in front of it.
	 */
	if (*pattern == '/') {
		pattern++;
		patternlen--;
		prefix--;
	}

	/*
	 * baselen does not count the trailing slash. base[] may or
	 * may not end with a trailing slash though.
	 */
	if (pathlen < baselen + 1 ||
	    (baselen && pathname[baselen] != '/') ||
	    fspathncmp(pathname, base, baselen))
		return 0;

	namelen = baselen ? pathlen - baselen - 1 : pathlen;
	name = pathname + pathlen - namelen;

	if (prefix) {
		/*
		 * if the non-wildcard part is longer than the
		 * remaining pathname, surely it cannot match.
		 */
		if (prefix > namelen)
			return 0;

		if (fspathncmp(pattern, name, prefix))
			return 0;
		pattern += prefix;
		patternlen -= prefix;
		name    += prefix;
		namelen -= prefix;

		/*
		 * If the whole pattern did not have a wildcard,
		 * then our prefix match is all we need; we
		 * do not need to call fnmatch at all.
		 */
		if (!patternlen && !namelen)
			return 1;
	}

	return fnmatch_icase_mem(pattern, patternlen,
				 name, namelen,
				 WM_PATHNAME) == 0;
}

/*
 * Scan the given exclude list in reverse to see whether pathname
 * should be ignored.  The first match (i.e. the last on the list), if
 * any, determines the fate.  Returns the exclude_list element which
 * matched, or NULL for undecided.
 */
static struct path_pattern *last_matching_pattern_from_list(const char *pathname,
						       int pathlen,
						       const char *basename,
						       int *dtype,
						       struct pattern_list *pl,
						       struct index_state *istate)
{
	struct path_pattern *res = NULL; /* undecided */
	int i;

	if (!pl->nr)
		return NULL;	/* undefined */

	for (i = pl->nr - 1; 0 <= i; i--) {
		struct path_pattern *pattern = pl->patterns[i];
		const char *exclude = pattern->pattern;
		int prefix = pattern->nowildcardlen;

		if (pattern->flags & PATTERN_FLAG_MUSTBEDIR) {
			*dtype = resolve_dtype(*dtype, istate, pathname, pathlen);
			if (*dtype != DT_DIR)
				continue;
		}

		if (pattern->flags & PATTERN_FLAG_NODIR) {
			if (match_basename(basename,
					   pathlen - (basename - pathname),
					   exclude, prefix, pattern->patternlen,
					   pattern->flags)) {
				res = pattern;
				break;
			}
			continue;
		}

		assert(pattern->baselen == 0 ||
		       pattern->base[pattern->baselen - 1] == '/');
		if (match_pathname(pathname, pathlen,
				   pattern->base,
				   pattern->baselen ? pattern->baselen - 1 : 0,
				   exclude, prefix, pattern->patternlen,
				   pattern->flags)) {
			res = pattern;
			break;
		}
	}
	return res;
}

/*
 * Scan the list of patterns to determine if the ordered list
 * of patterns matches on 'pathname'.
 *
 * Return 1 for a match, 0 for not matched and -1 for undecided.
 */
enum pattern_match_result path_matches_pattern_list(
				const char *pathname, int pathlen,
				const char *basename, int *dtype,
				struct pattern_list *pl,
				struct index_state *istate)
{
	struct path_pattern *pattern;
	struct strbuf parent_pathname = STRBUF_INIT;
	int result = NOT_MATCHED;
	const char *slash_pos;

	if (!pl->use_cone_patterns) {
		pattern = last_matching_pattern_from_list(pathname, pathlen, basename,
							dtype, pl, istate);
		if (pattern) {
			if (pattern->flags & PATTERN_FLAG_NEGATIVE)
				return NOT_MATCHED;
			else
				return MATCHED;
		}

		return UNDECIDED;
	}

	if (pl->full_cone)
		return MATCHED;

	strbuf_addch(&parent_pathname, '/');
	strbuf_add(&parent_pathname, pathname, pathlen);

	if (hashmap_contains_path(&pl->recursive_hashmap,
				  &parent_pathname)) {
		result = MATCHED_RECURSIVE;
		goto done;
	}

	slash_pos = strrchr(parent_pathname.buf, '/');

	if (slash_pos == parent_pathname.buf) {
		/* include every file in root */
		result = MATCHED;
		goto done;
	}

	strbuf_setlen(&parent_pathname, slash_pos - parent_pathname.buf);

	if (hashmap_contains_path(&pl->parent_hashmap, &parent_pathname)) {
		result = MATCHED;
		goto done;
	}

	if (hashmap_contains_parent(&pl->recursive_hashmap,
				    pathname,
				    &parent_pathname))
		result = MATCHED_RECURSIVE;

done:
	strbuf_release(&parent_pathname);
	return result;
}

static struct path_pattern *last_matching_pattern_from_lists(
		struct dir_struct *dir, struct index_state *istate,
		const char *pathname, int pathlen,
		const char *basename, int *dtype_p)
{
	int i, j;
	struct exclude_list_group *group;
	struct path_pattern *pattern;
	for (i = EXC_CMDL; i <= EXC_FILE; i++) {
		group = &dir->exclude_list_group[i];
		for (j = group->nr - 1; j >= 0; j--) {
			pattern = last_matching_pattern_from_list(
				pathname, pathlen, basename, dtype_p,
				&group->pl[j], istate);
			if (pattern)
				return pattern;
		}
	}
	return NULL;
}

/*
 * Loads the per-directory exclude list for the substring of base
 * which has a char length of baselen.
 */
static void prep_exclude(struct dir_struct *dir,
			 struct index_state *istate,
			 const char *base, int baselen)
{
	struct exclude_list_group *group;
	struct pattern_list *pl;
	struct exclude_stack *stk = NULL;
	struct untracked_cache_dir *untracked;
	int current;

	group = &dir->exclude_list_group[EXC_DIRS];

	/*
	 * Pop the exclude lists from the EXCL_DIRS exclude_list_group
	 * which originate from directories not in the prefix of the
	 * path being checked.
	 */
	while ((stk = dir->exclude_stack) != NULL) {
		if (stk->baselen <= baselen &&
		    !strncmp(dir->basebuf.buf, base, stk->baselen))
			break;
		pl = &group->pl[dir->exclude_stack->exclude_ix];
		dir->exclude_stack = stk->prev;
		dir->pattern = NULL;
		free((char *)pl->src); /* see strbuf_detach() below */
		clear_pattern_list(pl);
		free(stk);
		group->nr--;
	}

	/* Skip traversing into sub directories if the parent is excluded */
	if (dir->pattern)
		return;

	/*
	 * Lazy initialization. All call sites currently just
	 * memset(dir, 0, sizeof(*dir)) before use. Changing all of
	 * them seems lots of work for little benefit.
	 */
	if (!dir->basebuf.buf)
		strbuf_init(&dir->basebuf, PATH_MAX);

	/* Read from the parent directories and push them down. */
	current = stk ? stk->baselen : -1;
	strbuf_setlen(&dir->basebuf, current < 0 ? 0 : current);
	if (dir->untracked)
		untracked = stk ? stk->ucd : dir->untracked->root;
	else
		untracked = NULL;

	while (current < baselen) {
		const char *cp;
		struct oid_stat oid_stat;

		stk = xcalloc(1, sizeof(*stk));
		if (current < 0) {
			cp = base;
			current = 0;
		} else {
			cp = strchr(base + current + 1, '/');
			if (!cp)
				die("oops in prep_exclude");
			cp++;
			untracked =
				lookup_untracked(dir->untracked, untracked,
						 base + current,
						 cp - base - current);
		}
		stk->prev = dir->exclude_stack;
		stk->baselen = cp - base;
		stk->exclude_ix = group->nr;
		stk->ucd = untracked;
		pl = add_pattern_list(dir, EXC_DIRS, NULL);
		strbuf_add(&dir->basebuf, base + current, stk->baselen - current);
		assert(stk->baselen == dir->basebuf.len);

		/* Abort if the directory is excluded */
		if (stk->baselen) {
			int dt = DT_DIR;
			dir->basebuf.buf[stk->baselen - 1] = 0;
			dir->pattern = last_matching_pattern_from_lists(dir,
									istate,
				dir->basebuf.buf, stk->baselen - 1,
				dir->basebuf.buf + current, &dt);
			dir->basebuf.buf[stk->baselen - 1] = '/';
			if (dir->pattern &&
			    dir->pattern->flags & PATTERN_FLAG_NEGATIVE)
				dir->pattern = NULL;
			if (dir->pattern) {
				dir->exclude_stack = stk;
				return;
			}
		}

		/* Try to read per-directory file */
		oidclr(&oid_stat.oid);
		oid_stat.valid = 0;
		if (dir->exclude_per_dir &&
		    /*
		     * If we know that no files have been added in
		     * this directory (i.e. valid_cached_dir() has
		     * been executed and set untracked->valid) ..
		     */
		    (!untracked || !untracked->valid ||
		     /*
		      * .. and .gitignore does not exist before
		      * (i.e. null exclude_oid). Then we can skip
		      * loading .gitignore, which would result in
		      * ENOENT anyway.
		      */
		     !is_null_oid(&untracked->exclude_oid))) {
			/*
			 * dir->basebuf gets reused by the traversal, but we
			 * need fname to remain unchanged to ensure the src
			 * member of each struct path_pattern correctly
			 * back-references its source file.  Other invocations
			 * of add_pattern_list provide stable strings, so we
			 * strbuf_detach() and free() here in the caller.
			 */
			struct strbuf sb = STRBUF_INIT;
			strbuf_addbuf(&sb, &dir->basebuf);
			strbuf_addstr(&sb, dir->exclude_per_dir);
			pl->src = strbuf_detach(&sb, NULL);
			add_patterns(pl->src, pl->src, stk->baselen, pl, istate,
				     untracked ? &oid_stat : NULL);
		}
		/*
		 * NEEDSWORK: when untracked cache is enabled, prep_exclude()
		 * will first be called in valid_cached_dir() then maybe many
		 * times more in last_matching_pattern(). When the cache is
		 * used, last_matching_pattern() will not be called and
		 * reading .gitignore content will be a waste.
		 *
		 * So when it's called by valid_cached_dir() and we can get
		 * .gitignore SHA-1 from the index (i.e. .gitignore is not
		 * modified on work tree), we could delay reading the
		 * .gitignore content until we absolutely need it in
		 * last_matching_pattern(). Be careful about ignore rule
		 * order, though, if you do that.
		 */
		if (untracked &&
		    !oideq(&oid_stat.oid, &untracked->exclude_oid)) {
			invalidate_gitignore(dir->untracked, untracked);
			oidcpy(&untracked->exclude_oid, &oid_stat.oid);
		}
		dir->exclude_stack = stk;
		current = stk->baselen;
	}
	strbuf_setlen(&dir->basebuf, baselen);
}

/*
 * Loads the exclude lists for the directory containing pathname, then
 * scans all exclude lists to determine whether pathname is excluded.
 * Returns the exclude_list element which matched, or NULL for
 * undecided.
 */
struct path_pattern *last_matching_pattern(struct dir_struct *dir,
				      struct index_state *istate,
				      const char *pathname,
				      int *dtype_p)
{
	int pathlen = strlen(pathname);
	const char *basename = strrchr(pathname, '/');
	basename = (basename) ? basename+1 : pathname;

	prep_exclude(dir, istate, pathname, basename-pathname);

	if (dir->pattern)
		return dir->pattern;

	return last_matching_pattern_from_lists(dir, istate, pathname, pathlen,
			basename, dtype_p);
}

/*
 * Loads the exclude lists for the directory containing pathname, then
 * scans all exclude lists to determine whether pathname is excluded.
 * Returns 1 if true, otherwise 0.
 */
int is_excluded(struct dir_struct *dir, struct index_state *istate,
		const char *pathname, int *dtype_p)
{
	struct path_pattern *pattern =
		last_matching_pattern(dir, istate, pathname, dtype_p);
	if (pattern)
		return pattern->flags & PATTERN_FLAG_NEGATIVE ? 0 : 1;
	return 0;
}

static struct dir_entry *dir_entry_new(const char *pathname, int len)
{
	struct dir_entry *ent;

	FLEX_ALLOC_MEM(ent, name, pathname, len);
	ent->len = len;
	return ent;
}

static struct dir_entry *dir_add_name(struct dir_struct *dir,
				      struct index_state *istate,
				      const char *pathname, int len)
{
	if (index_file_exists(istate, pathname, len, ignore_case))
		return NULL;

	ALLOC_GROW(dir->entries, dir->nr+1, dir->alloc);
	return dir->entries[dir->nr++] = dir_entry_new(pathname, len);
}

struct dir_entry *dir_add_ignored(struct dir_struct *dir,
				  struct index_state *istate,
				  const char *pathname, int len)
{
	if (!index_name_is_other(istate, pathname, len))
		return NULL;

	ALLOC_GROW(dir->ignored, dir->ignored_nr+1, dir->ignored_alloc);
	return dir->ignored[dir->ignored_nr++] = dir_entry_new(pathname, len);
}

enum exist_status {
	index_nonexistent = 0,
	index_directory,
	index_gitdir
};

/*
 * Do not use the alphabetically sorted index to look up
 * the directory name; instead, use the case insensitive
 * directory hash.
 */
static enum exist_status directory_exists_in_index_icase(struct index_state *istate,
							 const char *dirname, int len)
{
	struct cache_entry *ce;

	if (index_dir_exists(istate, dirname, len))
		return index_directory;

	ce = index_file_exists(istate, dirname, len, ignore_case);
	if (ce && S_ISGITLINK(ce->ce_mode))
		return index_gitdir;

	return index_nonexistent;
}

/*
 * The index sorts alphabetically by entry name, which
 * means that a gitlink sorts as '\0' at the end, while
 * a directory (which is defined not as an entry, but as
 * the files it contains) will sort with the '/' at the
 * end.
 */
static enum exist_status directory_exists_in_index(struct index_state *istate,
						   const char *dirname, int len)
{
	int pos;

	if (ignore_case)
		return directory_exists_in_index_icase(istate, dirname, len);

	pos = index_name_pos(istate, dirname, len);
	if (pos < 0)
		pos = -pos-1;
	while (pos < istate->cache_nr) {
		const struct cache_entry *ce = istate->cache[pos++];
		unsigned char endchar;

		if (strncmp(ce->name, dirname, len))
			break;
		endchar = ce->name[len];
		if (endchar > '/')
			break;
		if (endchar == '/')
			return index_directory;
		if (!endchar && S_ISGITLINK(ce->ce_mode))
			return index_gitdir;
	}
	return index_nonexistent;
}

/*
 * When we find a directory when traversing the filesystem, we
 * have three distinct cases:
 *
 *  - ignore it
 *  - see it as a directory
 *  - recurse into it
 *
 * and which one we choose depends on a combination of existing
 * git index contents and the flags passed into the directory
 * traversal routine.
 *
 * Case 1: If we *already* have entries in the index under that
 * directory name, we always recurse into the directory to see
 * all the files.
 *
 * Case 2: If we *already* have that directory name as a gitlink,
 * we always continue to see it as a gitlink, regardless of whether
 * there is an actual git directory there or not (it might not
 * be checked out as a subproject!)
 *
 * Case 3: if we didn't have it in the index previously, we
 * have a few sub-cases:
 *
 *  (a) if "show_other_directories" is true, we show it as
 *      just a directory, unless "hide_empty_directories" is
 *      also true, in which case we need to check if it contains any
 *      untracked and / or ignored files.
 *  (b) if it looks like a git directory, and we don't have
 *      'no_gitlinks' set we treat it as a gitlink, and show it
 *      as a directory.
 *  (c) otherwise, we recurse into it.
 */
static enum path_treatment treat_directory(struct dir_struct *dir,
	struct index_state *istate,
	struct untracked_cache_dir *untracked,
	const char *dirname, int len, int baselen, int exclude,
	const struct pathspec *pathspec)
{
	int nested_repo = 0;

	/* The "len-1" is to strip the final '/' */
	switch (directory_exists_in_index(istate, dirname, len-1)) {
	case index_directory:
		return path_recurse;

	case index_gitdir:
		return path_none;

	case index_nonexistent:
		if ((dir->flags & DIR_SKIP_NESTED_GIT) ||
		    !(dir->flags & DIR_NO_GITLINKS)) {
			struct strbuf sb = STRBUF_INIT;
			strbuf_addstr(&sb, dirname);
			nested_repo = is_nonbare_repository_dir(&sb);
			strbuf_release(&sb);
		}
		if (nested_repo)
			return ((dir->flags & DIR_SKIP_NESTED_GIT) ? path_none :
				(exclude ? path_excluded : path_untracked));

		if (dir->flags & DIR_SHOW_OTHER_DIRECTORIES)
			break;
		if (exclude &&
			(dir->flags & DIR_SHOW_IGNORED_TOO) &&
			(dir->flags & DIR_SHOW_IGNORED_TOO_MODE_MATCHING)) {

			/*
			 * This is an excluded directory and we are
			 * showing ignored paths that match an exclude
			 * pattern.  (e.g. show directory as ignored
			 * only if it matches an exclude pattern).
			 * This path will either be 'path_excluded`
			 * (if we are showing empty directories or if
			 * the directory is not empty), or will be
			 * 'path_none' (empty directory, and we are
			 * not showing empty directories).
			 */
			if (!(dir->flags & DIR_HIDE_EMPTY_DIRECTORIES))
				return path_excluded;

			if (read_directory_recursive(dir, istate, dirname, len,
						     untracked, 1, 1, pathspec) == path_excluded)
				return path_excluded;

			return path_none;
		}
		return path_recurse;
	}

	/* This is the "show_other_directories" case */

	if (!(dir->flags & DIR_HIDE_EMPTY_DIRECTORIES))
		return exclude ? path_excluded : path_untracked;

	untracked = lookup_untracked(dir->untracked, untracked,
				     dirname + baselen, len - baselen);

	/*
	 * If this is an excluded directory, then we only need to check if
	 * the directory contains any files.
	 */
	return read_directory_recursive(dir, istate, dirname, len,
					untracked, 1, exclude, pathspec);
}

/*
 * This is an inexact early pruning of any recursive directory
 * reading - if the path cannot possibly be in the pathspec,
 * return true, and we'll skip it early.
 */
static int simplify_away(const char *path, int pathlen,
			 const struct pathspec *pathspec)
{
	int i;

	if (!pathspec || !pathspec->nr)
		return 0;

	GUARD_PATHSPEC(pathspec,
		       PATHSPEC_FROMTOP |
		       PATHSPEC_MAXDEPTH |
		       PATHSPEC_LITERAL |
		       PATHSPEC_GLOB |
		       PATHSPEC_ICASE |
		       PATHSPEC_EXCLUDE |
		       PATHSPEC_ATTR);

	for (i = 0; i < pathspec->nr; i++) {
		const struct pathspec_item *item = &pathspec->items[i];
		int len = item->nowildcard_len;

		if (len > pathlen)
			len = pathlen;
		if (!ps_strncmp(item, item->match, path, len))
			return 0;
	}

	return 1;
}

/*
 * This function tells us whether an excluded path matches a
 * list of "interesting" pathspecs. That is, whether a path matched
 * by any of the pathspecs could possibly be ignored by excluding
 * the specified path. This can happen if:
 *
 *   1. the path is mentioned explicitly in the pathspec
 *
 *   2. the path is a directory prefix of some element in the
 *      pathspec
 */
static int exclude_matches_pathspec(const char *path, int pathlen,
				    const struct pathspec *pathspec)
{
	int i;

	if (!pathspec || !pathspec->nr)
		return 0;

	GUARD_PATHSPEC(pathspec,
		       PATHSPEC_FROMTOP |
		       PATHSPEC_MAXDEPTH |
		       PATHSPEC_LITERAL |
		       PATHSPEC_GLOB |
		       PATHSPEC_ICASE |
		       PATHSPEC_EXCLUDE);

	for (i = 0; i < pathspec->nr; i++) {
		const struct pathspec_item *item = &pathspec->items[i];
		int len = item->nowildcard_len;

		if (len == pathlen &&
		    !ps_strncmp(item, item->match, path, pathlen))
			return 1;
		if (len > pathlen &&
		    item->match[pathlen] == '/' &&
		    !ps_strncmp(item, item->match, path, pathlen))
			return 1;
	}
	return 0;
}

static int get_index_dtype(struct index_state *istate,
			   const char *path, int len)
{
	int pos;
	const struct cache_entry *ce;

	ce = index_file_exists(istate, path, len, 0);
	if (ce) {
		if (!ce_uptodate(ce))
			return DT_UNKNOWN;
		if (S_ISGITLINK(ce->ce_mode))
			return DT_DIR;
		/*
		 * Nobody actually cares about the
		 * difference between DT_LNK and DT_REG
		 */
		return DT_REG;
	}

	/* Try to look it up as a directory */
	pos = index_name_pos(istate, path, len);
	if (pos >= 0)
		return DT_UNKNOWN;
	pos = -pos-1;
	while (pos < istate->cache_nr) {
		ce = istate->cache[pos++];
		if (strncmp(ce->name, path, len))
			break;
		if (ce->name[len] > '/')
			break;
		if (ce->name[len] < '/')
			continue;
		if (!ce_uptodate(ce))
			break;	/* continue? */
		return DT_DIR;
	}
	return DT_UNKNOWN;
}

static int resolve_dtype(int dtype, struct index_state *istate,
			 const char *path, int len)
{
	struct stat st;

	if (dtype != DT_UNKNOWN)
		return dtype;
	dtype = get_index_dtype(istate, path, len);
	if (dtype != DT_UNKNOWN)
		return dtype;
	if (lstat(path, &st))
		return dtype;
	if (S_ISREG(st.st_mode))
		return DT_REG;
	if (S_ISDIR(st.st_mode))
		return DT_DIR;
	if (S_ISLNK(st.st_mode))
		return DT_LNK;
	return dtype;
}

static enum path_treatment treat_one_path(struct dir_struct *dir,
					  struct untracked_cache_dir *untracked,
					  struct index_state *istate,
					  struct strbuf *path,
					  int baselen,
					  const struct pathspec *pathspec,
					  int dtype)
{
	int exclude;
	int has_path_in_index = !!index_file_exists(istate, path->buf, path->len, ignore_case);
	enum path_treatment path_treatment;

	dtype = resolve_dtype(dtype, istate, path->buf, path->len);

	/* Always exclude indexed files */
	if (dtype != DT_DIR && has_path_in_index)
		return path_none;

	/*
	 * When we are looking at a directory P in the working tree,
	 * there are three cases:
	 *
	 * (1) P exists in the index.  Everything inside the directory P in
	 * the working tree needs to go when P is checked out from the
	 * index.
	 *
	 * (2) P does not exist in the index, but there is P/Q in the index.
	 * We know P will stay a directory when we check out the contents
	 * of the index, but we do not know yet if there is a directory
	 * P/Q in the working tree to be killed, so we need to recurse.
	 *
	 * (3) P does not exist in the index, and there is no P/Q in the index
	 * to require P to be a directory, either.  Only in this case, we
	 * know that everything inside P will not be killed without
	 * recursing.
	 */
	if ((dir->flags & DIR_COLLECT_KILLED_ONLY) &&
	    (dtype == DT_DIR) &&
	    !has_path_in_index &&
	    (directory_exists_in_index(istate, path->buf, path->len) == index_nonexistent))
		return path_none;

	exclude = is_excluded(dir, istate, path->buf, &dtype);

	/*
	 * Excluded? If we don't explicitly want to show
	 * ignored files, ignore it
	 */
	if (exclude && !(dir->flags & (DIR_SHOW_IGNORED|DIR_SHOW_IGNORED_TOO)))
		return path_excluded;

	switch (dtype) {
	default:
		return path_none;
	case DT_DIR:
		strbuf_addch(path, '/');
		path_treatment = treat_directory(dir, istate, untracked,
						 path->buf, path->len,
						 baselen, exclude, pathspec);
		/*
		 * If 1) we only want to return directories that
		 * match an exclude pattern and 2) this directory does
		 * not match an exclude pattern but all of its
		 * contents are excluded, then indicate that we should
		 * recurse into this directory (instead of marking the
		 * directory itself as an ignored path).
		 */
		if (!exclude &&
		    path_treatment == path_excluded &&
		    (dir->flags & DIR_SHOW_IGNORED_TOO) &&
		    (dir->flags & DIR_SHOW_IGNORED_TOO_MODE_MATCHING))
			return path_recurse;
		return path_treatment;
	case DT_REG:
	case DT_LNK:
		return exclude ? path_excluded : path_untracked;
	}
}

static enum path_treatment treat_path_fast(struct dir_struct *dir,
					   struct untracked_cache_dir *untracked,
					   struct cached_dir *cdir,
					   struct index_state *istate,
					   struct strbuf *path,
					   int baselen,
					   const struct pathspec *pathspec)
{
	strbuf_setlen(path, baselen);
	if (!cdir->ucd) {
		strbuf_addstr(path, cdir->file);
		return path_untracked;
	}
	strbuf_addstr(path, cdir->ucd->name);
	/* treat_one_path() does this before it calls treat_directory() */
	strbuf_complete(path, '/');
	if (cdir->ucd->check_only)
		/*
		 * check_only is set as a result of treat_directory() getting
		 * to its bottom. Verify again the same set of directories
		 * with check_only set.
		 */
		return read_directory_recursive(dir, istate, path->buf, path->len,
						cdir->ucd, 1, 0, pathspec);
	/*
	 * We get path_recurse in the first run when
	 * directory_exists_in_index() returns index_nonexistent. We
	 * are sure that new changes in the index does not impact the
	 * outcome. Return now.
	 */
	return path_recurse;
}

static enum path_treatment treat_path(struct dir_struct *dir,
				      struct untracked_cache_dir *untracked,
				      struct cached_dir *cdir,
				      struct index_state *istate,
				      struct strbuf *path,
				      int baselen,
				      const struct pathspec *pathspec)
{
	if (!cdir->d_name)
		return treat_path_fast(dir, untracked, cdir, istate, path,
				       baselen, pathspec);
	if (is_dot_or_dotdot(cdir->d_name) || !fspathcmp(cdir->d_name, ".git"))
		return path_none;
	strbuf_setlen(path, baselen);
	strbuf_addstr(path, cdir->d_name);
	if (simplify_away(path->buf, path->len, pathspec))
		return path_none;

	return treat_one_path(dir, untracked, istate, path, baselen, pathspec,
			      cdir->d_type);
}

static void add_untracked(struct untracked_cache_dir *dir, const char *name)
{
	if (!dir)
		return;
	ALLOC_GROW(dir->untracked, dir->untracked_nr + 1,
		   dir->untracked_alloc);
	dir->untracked[dir->untracked_nr++] = xstrdup(name);
}

static int valid_cached_dir(struct dir_struct *dir,
			    struct untracked_cache_dir *untracked,
			    struct index_state *istate,
			    struct strbuf *path,
			    int check_only)
{
	struct stat st;

	if (!untracked)
		return 0;

	/*
	 * With fsmonitor, we can trust the untracked cache's valid field.
	 */
	refresh_fsmonitor(istate);
	if (!(dir->untracked->use_fsmonitor && untracked->valid)) {
		if (lstat(path->len ? path->buf : ".", &st)) {
			memset(&untracked->stat_data, 0, sizeof(untracked->stat_data));
			return 0;
		}
		if (!untracked->valid ||
			match_stat_data_racy(istate, &untracked->stat_data, &st)) {
			fill_stat_data(&untracked->stat_data, &st);
			return 0;
		}
	}

	if (untracked->check_only != !!check_only)
		return 0;

	/*
	 * prep_exclude will be called eventually on this directory,
	 * but it's called much later in last_matching_pattern(). We
	 * need it now to determine the validity of the cache for this
	 * path. The next calls will be nearly no-op, the way
	 * prep_exclude() is designed.
	 */
	if (path->len && path->buf[path->len - 1] != '/') {
		strbuf_addch(path, '/');
		prep_exclude(dir, istate, path->buf, path->len);
		strbuf_setlen(path, path->len - 1);
	} else
		prep_exclude(dir, istate, path->buf, path->len);

	/* hopefully prep_exclude() haven't invalidated this entry... */
	return untracked->valid;
}

static int open_cached_dir(struct cached_dir *cdir,
			   struct dir_struct *dir,
			   struct untracked_cache_dir *untracked,
			   struct index_state *istate,
			   struct strbuf *path,
			   int check_only)
{
	const char *c_path;

	memset(cdir, 0, sizeof(*cdir));
	cdir->untracked = untracked;
	if (valid_cached_dir(dir, untracked, istate, path, check_only))
		return 0;
	c_path = path->len ? path->buf : ".";
	cdir->fdir = opendir(c_path);
	if (!cdir->fdir)
		warning_errno(_("could not open directory '%s'"), c_path);
	if (dir->untracked) {
		invalidate_directory(dir->untracked, untracked);
		dir->untracked->dir_opened++;
	}
	if (!cdir->fdir)
		return -1;
	return 0;
}

static int read_cached_dir(struct cached_dir *cdir)
{
	struct dirent *de;

	if (cdir->fdir) {
		de = readdir(cdir->fdir);
		if (!de) {
			cdir->d_name = NULL;
			cdir->d_type = DT_UNKNOWN;
			return -1;
		}
		cdir->d_name = de->d_name;
		cdir->d_type = DTYPE(de);
		return 0;
	}
	while (cdir->nr_dirs < cdir->untracked->dirs_nr) {
		struct untracked_cache_dir *d = cdir->untracked->dirs[cdir->nr_dirs];
		if (!d->recurse) {
			cdir->nr_dirs++;
			continue;
		}
		cdir->ucd = d;
		cdir->nr_dirs++;
		return 0;
	}
	cdir->ucd = NULL;
	if (cdir->nr_files < cdir->untracked->untracked_nr) {
		struct untracked_cache_dir *d = cdir->untracked;
		cdir->file = d->untracked[cdir->nr_files++];
		return 0;
	}
	return -1;
}

static void close_cached_dir(struct cached_dir *cdir)
{
	if (cdir->fdir)
		closedir(cdir->fdir);
	/*
	 * We have gone through this directory and found no untracked
	 * entries. Mark it valid.
	 */
	if (cdir->untracked) {
		cdir->untracked->valid = 1;
		cdir->untracked->recurse = 1;
	}
}

static void add_path_to_appropriate_result_list(struct dir_struct *dir,
	struct untracked_cache_dir *untracked,
	struct cached_dir *cdir,
	struct index_state *istate,
	struct strbuf *path,
	int baselen,
	const struct pathspec *pathspec,
	enum path_treatment state)
{
	/* add the path to the appropriate result list */
	switch (state) {
	case path_excluded:
		if (dir->flags & DIR_SHOW_IGNORED)
			dir_add_name(dir, istate, path->buf, path->len);
		else if ((dir->flags & DIR_SHOW_IGNORED_TOO) ||
			((dir->flags & DIR_COLLECT_IGNORED) &&
			exclude_matches_pathspec(path->buf, path->len,
						 pathspec)))
			dir_add_ignored(dir, istate, path->buf, path->len);
		break;

	case path_untracked:
		if (dir->flags & DIR_SHOW_IGNORED)
			break;
		dir_add_name(dir, istate, path->buf, path->len);
		if (cdir->fdir)
			add_untracked(untracked, path->buf + baselen);
		break;

	default:
		break;
	}
}

/*
 * Read a directory tree. We currently ignore anything but
 * directories, regular files and symlinks. That's because git
 * doesn't handle them at all yet. Maybe that will change some
 * day.
 *
 * Also, we ignore the name ".git" (even if it is not a directory).
 * That likely will not change.
 *
 * If 'stop_at_first_file' is specified, 'path_excluded' is returned
 * to signal that a file was found. This is the least significant value that
 * indicates that a file was encountered that does not depend on the order of
 * whether an untracked or exluded path was encountered first.
 *
 * Returns the most significant path_treatment value encountered in the scan.
 * If 'stop_at_first_file' is specified, `path_excluded` is the most
 * significant path_treatment value that will be returned.
 */

static enum path_treatment read_directory_recursive(struct dir_struct *dir,
	struct index_state *istate, const char *base, int baselen,
	struct untracked_cache_dir *untracked, int check_only,
	int stop_at_first_file, const struct pathspec *pathspec)
{
	/*
	 * WARNING WARNING WARNING:
	 *
	 * Any updates to the traversal logic here may need corresponding
	 * updates in treat_leading_path().  See the commit message for the
	 * commit adding this warning as well as the commit preceding it
	 * for details.
	 */

	struct cached_dir cdir;
	enum path_treatment state, subdir_state, dir_state = path_none;
	struct strbuf path = STRBUF_INIT;

	strbuf_add(&path, base, baselen);

	if (open_cached_dir(&cdir, dir, untracked, istate, &path, check_only))
		goto out;

	if (untracked)
		untracked->check_only = !!check_only;

	while (!read_cached_dir(&cdir)) {
		/* check how the file or directory should be treated */
		state = treat_path(dir, untracked, &cdir, istate, &path,
				   baselen, pathspec);

		if (state > dir_state)
			dir_state = state;

		/* recurse into subdir if instructed by treat_path */
		if ((state == path_recurse) ||
			((state == path_untracked) &&
			 (resolve_dtype(cdir.d_type, istate, path.buf, path.len) == DT_DIR) &&
			 ((dir->flags & DIR_SHOW_IGNORED_TOO) ||
			  (pathspec &&
			   do_match_pathspec(istate, pathspec, path.buf, path.len,
					     baselen, NULL, DO_MATCH_LEADING_PATHSPEC) == MATCHED_RECURSIVELY_LEADING_PATHSPEC)))) {
			struct untracked_cache_dir *ud;
			ud = lookup_untracked(dir->untracked, untracked,
					      path.buf + baselen,
					      path.len - baselen);
			subdir_state =
				read_directory_recursive(dir, istate, path.buf,
							 path.len, ud,
							 check_only, stop_at_first_file, pathspec);
			if (subdir_state > dir_state)
				dir_state = subdir_state;

			if (pathspec &&
			    !match_pathspec(istate, pathspec, path.buf, path.len,
					    0 /* prefix */, NULL,
					    0 /* do NOT special case dirs */))
				state = path_none;
		}

		if (check_only) {
			if (stop_at_first_file) {
				/*
				 * If stopping at first file, then
				 * signal that a file was found by
				 * returning `path_excluded`. This is
				 * to return a consistent value
				 * regardless of whether an ignored or
				 * excluded file happened to be
				 * encountered 1st.
				 *
				 * In current usage, the
				 * `stop_at_first_file` is passed when
				 * an ancestor directory has matched
				 * an exclude pattern, so any found
				 * files will be excluded.
				 */
				if (dir_state >= path_excluded) {
					dir_state = path_excluded;
					break;
				}
			}

			/* abort early if maximum state has been reached */
			if (dir_state == path_untracked) {
				if (cdir.fdir)
					add_untracked(untracked, path.buf + baselen);
				break;
			}
			/* skip the dir_add_* part */
			continue;
		}

		add_path_to_appropriate_result_list(dir, untracked, &cdir,
						    istate, &path, baselen,
						    pathspec, state);
	}
	close_cached_dir(&cdir);
 out:
	strbuf_release(&path);

	return dir_state;
}

int cmp_dir_entry(const void *p1, const void *p2)
{
	const struct dir_entry *e1 = *(const struct dir_entry **)p1;
	const struct dir_entry *e2 = *(const struct dir_entry **)p2;

	return name_compare(e1->name, e1->len, e2->name, e2->len);
}

/* check if *out lexically strictly contains *in */
int check_dir_entry_contains(const struct dir_entry *out, const struct dir_entry *in)
{
	return (out->len < in->len) &&
		(out->name[out->len - 1] == '/') &&
		!memcmp(out->name, in->name, out->len);
}

static int treat_leading_path(struct dir_struct *dir,
			      struct index_state *istate,
			      const char *path, int len,
			      const struct pathspec *pathspec)
{
	/*
	 * WARNING WARNING WARNING:
	 *
	 * Any updates to the traversal logic here may need corresponding
	 * updates in read_directory_recursive().  See 777b420347 (dir:
	 * synchronize treat_leading_path() and read_directory_recursive(),
	 * 2019-12-19) and its parent commit for details.
	 */

	struct strbuf sb = STRBUF_INIT;
	struct strbuf subdir = STRBUF_INIT;
	int prevlen, baselen;
	const char *cp;
	struct cached_dir cdir;
	enum path_treatment state = path_none;

	/*
	 * For each directory component of path, we are going to check whether
	 * that path is relevant given the pathspec.  For example, if path is
	 *    foo/bar/baz/
	 * then we will ask treat_path() whether we should go into foo, then
	 * whether we should go into bar, then whether baz is relevant.
	 * Checking each is important because e.g. if path is
	 *    .git/info/
	 * then we need to check .git to know we shouldn't traverse it.
	 * If the return from treat_path() is:
	 *    * path_none, for any path, we return false.
	 *    * path_recurse, for all path components, we return true
	 *    * <anything else> for some intermediate component, we make sure
	 *        to add that path to the relevant list but return false
	 *        signifying that we shouldn't recurse into it.
	 */

	while (len && path[len - 1] == '/')
		len--;
	if (!len)
		return 1;

	memset(&cdir, 0, sizeof(cdir));
	cdir.d_type = DT_DIR;
	baselen = 0;
	prevlen = 0;
	while (1) {
		prevlen = baselen + !!baselen;
		cp = path + prevlen;
		cp = memchr(cp, '/', path + len - cp);
		if (!cp)
			baselen = len;
		else
			baselen = cp - path;
		strbuf_reset(&sb);
		strbuf_add(&sb, path, baselen);
		if (!is_directory(sb.buf))
			break;
		strbuf_reset(&sb);
		strbuf_add(&sb, path, prevlen);
		strbuf_reset(&subdir);
		strbuf_add(&subdir, path+prevlen, baselen-prevlen);
		cdir.d_name = subdir.buf;
		state = treat_path(dir, NULL, &cdir, istate, &sb, prevlen,
				    pathspec);
		if (state == path_untracked &&
		    resolve_dtype(cdir.d_type, istate, sb.buf, sb.len) == DT_DIR &&
		    (dir->flags & DIR_SHOW_IGNORED_TOO ||
		     do_match_pathspec(istate, pathspec, sb.buf, sb.len,
				       baselen, NULL, DO_MATCH_LEADING_PATHSPEC) == MATCHED_RECURSIVELY_LEADING_PATHSPEC)) {
			if (!match_pathspec(istate, pathspec, sb.buf, sb.len,
					    0 /* prefix */, NULL,
					    0 /* do NOT special case dirs */))
				state = path_none;
			add_path_to_appropriate_result_list(dir, NULL, &cdir,
							    istate,
							    &sb, baselen,
							    pathspec, state);
			state = path_recurse;
		}

		if (state != path_recurse)
			break; /* do not recurse into it */
		if (len <= baselen)
			break; /* finished checking */
	}
	add_path_to_appropriate_result_list(dir, NULL, &cdir, istate,
					    &sb, baselen, pathspec,
					    state);

	strbuf_release(&subdir);
	strbuf_release(&sb);
	return state == path_recurse;
}

static const char *get_ident_string(void)
{
	static struct strbuf sb = STRBUF_INIT;
	struct utsname uts;

	if (sb.len)
		return sb.buf;
	if (uname(&uts) < 0)
		die_errno(_("failed to get kernel name and information"));
	strbuf_addf(&sb, "Location %s, system %s", get_git_work_tree(),
		    uts.sysname);
	return sb.buf;
}

static int ident_in_untracked(const struct untracked_cache *uc)
{
	/*
	 * Previous git versions may have saved many NUL separated
	 * strings in the "ident" field, but it is insane to manage
	 * many locations, so just take care of the first one.
	 */

	return !strcmp(uc->ident.buf, get_ident_string());
}

static void set_untracked_ident(struct untracked_cache *uc)
{
	strbuf_reset(&uc->ident);
	strbuf_addstr(&uc->ident, get_ident_string());

	/*
	 * This strbuf used to contain a list of NUL separated
	 * strings, so save NUL too for backward compatibility.
	 */
	strbuf_addch(&uc->ident, 0);
}

static void new_untracked_cache(struct index_state *istate)
{
	struct untracked_cache *uc = xcalloc(1, sizeof(*uc));
	strbuf_init(&uc->ident, 100);
	uc->exclude_per_dir = ".gitignore";
	/* should be the same flags used by git-status */
	uc->dir_flags = DIR_SHOW_OTHER_DIRECTORIES | DIR_HIDE_EMPTY_DIRECTORIES;
	set_untracked_ident(uc);
	istate->untracked = uc;
	istate->cache_changed |= UNTRACKED_CHANGED;
}

void add_untracked_cache(struct index_state *istate)
{
	if (!istate->untracked) {
		new_untracked_cache(istate);
	} else {
		if (!ident_in_untracked(istate->untracked)) {
			free_untracked_cache(istate->untracked);
			new_untracked_cache(istate);
		}
	}
}

void remove_untracked_cache(struct index_state *istate)
{
	if (istate->untracked) {
		free_untracked_cache(istate->untracked);
		istate->untracked = NULL;
		istate->cache_changed |= UNTRACKED_CHANGED;
	}
}

static struct untracked_cache_dir *validate_untracked_cache(struct dir_struct *dir,
						      int base_len,
						      const struct pathspec *pathspec)
{
	struct untracked_cache_dir *root;
	static int untracked_cache_disabled = -1;

	if (!dir->untracked)
		return NULL;
	if (untracked_cache_disabled < 0)
		untracked_cache_disabled = git_env_bool("GIT_DISABLE_UNTRACKED_CACHE", 0);
	if (untracked_cache_disabled)
		return NULL;

	/*
	 * We only support $GIT_DIR/info/exclude and core.excludesfile
	 * as the global ignore rule files. Any other additions
	 * (e.g. from command line) invalidate the cache. This
	 * condition also catches running setup_standard_excludes()
	 * before setting dir->untracked!
	 */
	if (dir->unmanaged_exclude_files)
		return NULL;

	/*
	 * Optimize for the main use case only: whole-tree git
	 * status. More work involved in treat_leading_path() if we
	 * use cache on just a subset of the worktree. pathspec
	 * support could make the matter even worse.
	 */
	if (base_len || (pathspec && pathspec->nr))
		return NULL;

	/* Different set of flags may produce different results */
	if (dir->flags != dir->untracked->dir_flags ||
	    /*
	     * See treat_directory(), case index_nonexistent. Without
	     * this flag, we may need to also cache .git file content
	     * for the resolve_gitlink_ref() call, which we don't.
	     */
	    !(dir->flags & DIR_SHOW_OTHER_DIRECTORIES) ||
	    /* We don't support collecting ignore files */
	    (dir->flags & (DIR_SHOW_IGNORED | DIR_SHOW_IGNORED_TOO |
			   DIR_COLLECT_IGNORED)))
		return NULL;

	/*
	 * If we use .gitignore in the cache and now you change it to
	 * .gitexclude, everything will go wrong.
	 */
	if (dir->exclude_per_dir != dir->untracked->exclude_per_dir &&
	    strcmp(dir->exclude_per_dir, dir->untracked->exclude_per_dir))
		return NULL;

	/*
	 * EXC_CMDL is not considered in the cache. If people set it,
	 * skip the cache.
	 */
	if (dir->exclude_list_group[EXC_CMDL].nr)
		return NULL;

	if (!ident_in_untracked(dir->untracked)) {
		warning(_("untracked cache is disabled on this system or location"));
		return NULL;
	}

	if (!dir->untracked->root) {
		const int len = sizeof(*dir->untracked->root);
		dir->untracked->root = xmalloc(len);
		memset(dir->untracked->root, 0, len);
	}

	/* Validate $GIT_DIR/info/exclude and core.excludesfile */
	root = dir->untracked->root;
	if (!oideq(&dir->ss_info_exclude.oid,
		   &dir->untracked->ss_info_exclude.oid)) {
		invalidate_gitignore(dir->untracked, root);
		dir->untracked->ss_info_exclude = dir->ss_info_exclude;
	}
	if (!oideq(&dir->ss_excludes_file.oid,
		   &dir->untracked->ss_excludes_file.oid)) {
		invalidate_gitignore(dir->untracked, root);
		dir->untracked->ss_excludes_file = dir->ss_excludes_file;
	}

	/* Make sure this directory is not dropped out at saving phase */
	root->recurse = 1;
	return root;
}

int read_directory(struct dir_struct *dir, struct index_state *istate,
		   const char *path, int len, const struct pathspec *pathspec)
{
	struct untracked_cache_dir *untracked;

	trace_performance_enter();

	if (has_symlink_leading_path(path, len)) {
		trace_performance_leave("read directory %.*s", len, path);
		return dir->nr;
	}

	untracked = validate_untracked_cache(dir, len, pathspec);
	if (!untracked)
		/*
		 * make sure untracked cache code path is disabled,
		 * e.g. prep_exclude()
		 */
		dir->untracked = NULL;
	if (!len || treat_leading_path(dir, istate, path, len, pathspec))
		read_directory_recursive(dir, istate, path, len, untracked, 0, 0, pathspec);
	QSORT(dir->entries, dir->nr, cmp_dir_entry);
	QSORT(dir->ignored, dir->ignored_nr, cmp_dir_entry);

	/*
	 * If DIR_SHOW_IGNORED_TOO is set, read_directory_recursive() will
	 * also pick up untracked contents of untracked dirs; by default
	 * we discard these, but given DIR_KEEP_UNTRACKED_CONTENTS we do not.
	 */
	if ((dir->flags & DIR_SHOW_IGNORED_TOO) &&
		     !(dir->flags & DIR_KEEP_UNTRACKED_CONTENTS)) {
		int i, j;

		/* remove from dir->entries untracked contents of untracked dirs */
		for (i = j = 0; j < dir->nr; j++) {
			if (i &&
			    check_dir_entry_contains(dir->entries[i - 1], dir->entries[j])) {
				FREE_AND_NULL(dir->entries[j]);
			} else {
				dir->entries[i++] = dir->entries[j];
			}
		}

		dir->nr = i;
	}

	trace_performance_leave("read directory %.*s", len, path);
	if (dir->untracked) {
		static int force_untracked_cache = -1;
		static struct trace_key trace_untracked_stats = TRACE_KEY_INIT(UNTRACKED_STATS);

		if (force_untracked_cache < 0)
			force_untracked_cache =
				git_env_bool("GIT_FORCE_UNTRACKED_CACHE", 0);
		trace_printf_key(&trace_untracked_stats,
				 "node creation: %u\n"
				 "gitignore invalidation: %u\n"
				 "directory invalidation: %u\n"
				 "opendir: %u\n",
				 dir->untracked->dir_created,
				 dir->untracked->gitignore_invalidated,
				 dir->untracked->dir_invalidated,
				 dir->untracked->dir_opened);
		if (force_untracked_cache &&
			dir->untracked == istate->untracked &&
		    (dir->untracked->dir_opened ||
		     dir->untracked->gitignore_invalidated ||
		     dir->untracked->dir_invalidated))
			istate->cache_changed |= UNTRACKED_CHANGED;
		if (dir->untracked != istate->untracked) {
			FREE_AND_NULL(dir->untracked);
		}
	}
	return dir->nr;
}

int file_exists(const char *f)
{
	struct stat sb;
	return lstat(f, &sb) == 0;
}

int repo_file_exists(struct repository *repo, const char *path)
{
	if (repo != the_repository)
		BUG("do not know how to check file existence in arbitrary repo");

	return file_exists(path);
}

static int cmp_icase(char a, char b)
{
	if (a == b)
		return 0;
	if (ignore_case)
		return toupper(a) - toupper(b);
	return a - b;
}

/*
 * Given two normalized paths (a trailing slash is ok), if subdir is
 * outside dir, return -1.  Otherwise return the offset in subdir that
 * can be used as relative path to dir.
 */
int dir_inside_of(const char *subdir, const char *dir)
{
	int offset = 0;

	assert(dir && subdir && *dir && *subdir);

	while (*dir && *subdir && !cmp_icase(*dir, *subdir)) {
		dir++;
		subdir++;
		offset++;
	}

	/* hel[p]/me vs hel[l]/yeah */
	if (*dir && *subdir)
		return -1;

	if (!*subdir)
		return !*dir ? offset : -1; /* same dir */

	/* foo/[b]ar vs foo/[] */
	if (is_dir_sep(dir[-1]))
		return is_dir_sep(subdir[-1]) ? offset : -1;

	/* foo[/]bar vs foo[] */
	return is_dir_sep(*subdir) ? offset + 1 : -1;
}

int is_inside_dir(const char *dir)
{
	char *cwd;
	int rc;

	if (!dir)
		return 0;

	cwd = xgetcwd();
	rc = (dir_inside_of(cwd, dir) >= 0);
	free(cwd);
	return rc;
}

int is_empty_dir(const char *path)
{
	DIR *dir = opendir(path);
	struct dirent *e;
	int ret = 1;

	if (!dir)
		return 0;

	while ((e = readdir(dir)) != NULL)
		if (!is_dot_or_dotdot(e->d_name)) {
			ret = 0;
			break;
		}

	closedir(dir);
	return ret;
}

static int remove_dir_recurse(struct strbuf *path, int flag, int *kept_up)
{
	DIR *dir;
	struct dirent *e;
	int ret = 0, original_len = path->len, len, kept_down = 0;
	int only_empty = (flag & REMOVE_DIR_EMPTY_ONLY);
	int keep_toplevel = (flag & REMOVE_DIR_KEEP_TOPLEVEL);
	struct object_id submodule_head;

	if ((flag & REMOVE_DIR_KEEP_NESTED_GIT) &&
	    !resolve_gitlink_ref(path->buf, "HEAD", &submodule_head)) {
		/* Do not descend and nuke a nested git work tree. */
		if (kept_up)
			*kept_up = 1;
		return 0;
	}

	flag &= ~REMOVE_DIR_KEEP_TOPLEVEL;
	dir = opendir(path->buf);
	if (!dir) {
		if (errno == ENOENT)
			return keep_toplevel ? -1 : 0;
		else if (errno == EACCES && !keep_toplevel)
			/*
			 * An empty dir could be removable even if it
			 * is unreadable:
			 */
			return rmdir(path->buf);
		else
			return -1;
	}
	strbuf_complete(path, '/');

	len = path->len;
	while ((e = readdir(dir)) != NULL) {
		struct stat st;
		if (is_dot_or_dotdot(e->d_name))
			continue;

		strbuf_setlen(path, len);
		strbuf_addstr(path, e->d_name);
		if (lstat(path->buf, &st)) {
			if (errno == ENOENT)
				/*
				 * file disappeared, which is what we
				 * wanted anyway
				 */
				continue;
			/* fall through */
		} else if (S_ISDIR(st.st_mode)) {
			if (!remove_dir_recurse(path, flag, &kept_down))
				continue; /* happy */
		} else if (!only_empty &&
			   (!unlink(path->buf) || errno == ENOENT)) {
			continue; /* happy, too */
		}

		/* path too long, stat fails, or non-directory still exists */
		ret = -1;
		break;
	}
	closedir(dir);

	strbuf_setlen(path, original_len);
	if (!ret && !keep_toplevel && !kept_down)
		ret = (!rmdir(path->buf) || errno == ENOENT) ? 0 : -1;
	else if (kept_up)
		/*
		 * report the uplevel that it is not an error that we
		 * did not rmdir() our directory.
		 */
		*kept_up = !ret;
	return ret;
}

int remove_dir_recursively(struct strbuf *path, int flag)
{
	return remove_dir_recurse(path, flag, NULL);
}

static GIT_PATH_FUNC(git_path_info_exclude, "info/exclude")

void setup_standard_excludes(struct dir_struct *dir)
{
	dir->exclude_per_dir = ".gitignore";

	/* core.excludesfile defaulting to $XDG_CONFIG_HOME/git/ignore */
	if (!excludes_file)
		excludes_file = xdg_config_home("ignore");
	if (excludes_file && !access_or_warn(excludes_file, R_OK, 0))
		add_patterns_from_file_1(dir, excludes_file,
					 dir->untracked ? &dir->ss_excludes_file : NULL);

	/* per repository user preference */
	if (startup_info->have_repository) {
		const char *path = git_path_info_exclude();
		if (!access_or_warn(path, R_OK, 0))
			add_patterns_from_file_1(dir, path,
						 dir->untracked ? &dir->ss_info_exclude : NULL);
	}
}

int remove_path(const char *name)
{
	char *slash;

	if (unlink(name) && !is_missing_file_error(errno))
		return -1;

	slash = strrchr(name, '/');
	if (slash) {
		char *dirs = xstrdup(name);
		slash = dirs + (slash - name);
		do {
			*slash = '\0';
		} while (rmdir(dirs) == 0 && (slash = strrchr(dirs, '/')));
		free(dirs);
	}
	return 0;
}

/*
 * Frees memory within dir which was allocated for exclude lists and
 * the exclude_stack.  Does not free dir itself.
 */
void clear_directory(struct dir_struct *dir)
{
	int i, j;
	struct exclude_list_group *group;
	struct pattern_list *pl;
	struct exclude_stack *stk;

	for (i = EXC_CMDL; i <= EXC_FILE; i++) {
		group = &dir->exclude_list_group[i];
		for (j = 0; j < group->nr; j++) {
			pl = &group->pl[j];
			if (i == EXC_DIRS)
				free((char *)pl->src);
			clear_pattern_list(pl);
		}
		free(group->pl);
	}

	stk = dir->exclude_stack;
	while (stk) {
		struct exclude_stack *prev = stk->prev;
		free(stk);
		stk = prev;
	}
	strbuf_release(&dir->basebuf);
}

struct ondisk_untracked_cache {
	struct stat_data info_exclude_stat;
	struct stat_data excludes_file_stat;
	uint32_t dir_flags;
};

#define ouc_offset(x) offsetof(struct ondisk_untracked_cache, x)

struct write_data {
	int index;	   /* number of written untracked_cache_dir */
	struct ewah_bitmap *check_only; /* from untracked_cache_dir */
	struct ewah_bitmap *valid;	/* from untracked_cache_dir */
	struct ewah_bitmap *sha1_valid; /* set if exclude_sha1 is not null */
	struct strbuf out;
	struct strbuf sb_stat;
	struct strbuf sb_sha1;
};

static void stat_data_to_disk(struct stat_data *to, const struct stat_data *from)
{
	to->sd_ctime.sec  = htonl(from->sd_ctime.sec);
	to->sd_ctime.nsec = htonl(from->sd_ctime.nsec);
	to->sd_mtime.sec  = htonl(from->sd_mtime.sec);
	to->sd_mtime.nsec = htonl(from->sd_mtime.nsec);
	to->sd_dev	  = htonl(from->sd_dev);
	to->sd_ino	  = htonl(from->sd_ino);
	to->sd_uid	  = htonl(from->sd_uid);
	to->sd_gid	  = htonl(from->sd_gid);
	to->sd_size	  = htonl(from->sd_size);
}

static void write_one_dir(struct untracked_cache_dir *untracked,
			  struct write_data *wd)
{
	struct stat_data stat_data;
	struct strbuf *out = &wd->out;
	unsigned char intbuf[16];
	unsigned int intlen, value;
	int i = wd->index++;

	/*
	 * untracked_nr should be reset whenever valid is clear, but
	 * for safety..
	 */
	if (!untracked->valid) {
		untracked->untracked_nr = 0;
		untracked->check_only = 0;
	}

	if (untracked->check_only)
		ewah_set(wd->check_only, i);
	if (untracked->valid) {
		ewah_set(wd->valid, i);
		stat_data_to_disk(&stat_data, &untracked->stat_data);
		strbuf_add(&wd->sb_stat, &stat_data, sizeof(stat_data));
	}
	if (!is_null_oid(&untracked->exclude_oid)) {
		ewah_set(wd->sha1_valid, i);
		strbuf_add(&wd->sb_sha1, untracked->exclude_oid.hash,
			   the_hash_algo->rawsz);
	}

	intlen = encode_varint(untracked->untracked_nr, intbuf);
	strbuf_add(out, intbuf, intlen);

	/* skip non-recurse directories */
	for (i = 0, value = 0; i < untracked->dirs_nr; i++)
		if (untracked->dirs[i]->recurse)
			value++;
	intlen = encode_varint(value, intbuf);
	strbuf_add(out, intbuf, intlen);

	strbuf_add(out, untracked->name, strlen(untracked->name) + 1);

	for (i = 0; i < untracked->untracked_nr; i++)
		strbuf_add(out, untracked->untracked[i],
			   strlen(untracked->untracked[i]) + 1);

	for (i = 0; i < untracked->dirs_nr; i++)
		if (untracked->dirs[i]->recurse)
			write_one_dir(untracked->dirs[i], wd);
}

void write_untracked_extension(struct strbuf *out, struct untracked_cache *untracked)
{
	struct ondisk_untracked_cache *ouc;
	struct write_data wd;
	unsigned char varbuf[16];
	int varint_len;
	const unsigned hashsz = the_hash_algo->rawsz;

	ouc = xcalloc(1, sizeof(*ouc));
	stat_data_to_disk(&ouc->info_exclude_stat, &untracked->ss_info_exclude.stat);
	stat_data_to_disk(&ouc->excludes_file_stat, &untracked->ss_excludes_file.stat);
	ouc->dir_flags = htonl(untracked->dir_flags);

	varint_len = encode_varint(untracked->ident.len, varbuf);
	strbuf_add(out, varbuf, varint_len);
	strbuf_addbuf(out, &untracked->ident);

	strbuf_add(out, ouc, sizeof(*ouc));
	strbuf_add(out, untracked->ss_info_exclude.oid.hash, hashsz);
	strbuf_add(out, untracked->ss_excludes_file.oid.hash, hashsz);
	strbuf_add(out, untracked->exclude_per_dir, strlen(untracked->exclude_per_dir) + 1);
	FREE_AND_NULL(ouc);

	if (!untracked->root) {
		varint_len = encode_varint(0, varbuf);
		strbuf_add(out, varbuf, varint_len);
		return;
	}

	wd.index      = 0;
	wd.check_only = ewah_new();
	wd.valid      = ewah_new();
	wd.sha1_valid = ewah_new();
	strbuf_init(&wd.out, 1024);
	strbuf_init(&wd.sb_stat, 1024);
	strbuf_init(&wd.sb_sha1, 1024);
	write_one_dir(untracked->root, &wd);

	varint_len = encode_varint(wd.index, varbuf);
	strbuf_add(out, varbuf, varint_len);
	strbuf_addbuf(out, &wd.out);
	ewah_serialize_strbuf(wd.valid, out);
	ewah_serialize_strbuf(wd.check_only, out);
	ewah_serialize_strbuf(wd.sha1_valid, out);
	strbuf_addbuf(out, &wd.sb_stat);
	strbuf_addbuf(out, &wd.sb_sha1);
	strbuf_addch(out, '\0'); /* safe guard for string lists */

	ewah_free(wd.valid);
	ewah_free(wd.check_only);
	ewah_free(wd.sha1_valid);
	strbuf_release(&wd.out);
	strbuf_release(&wd.sb_stat);
	strbuf_release(&wd.sb_sha1);
}

static void free_untracked(struct untracked_cache_dir *ucd)
{
	int i;
	if (!ucd)
		return;
	for (i = 0; i < ucd->dirs_nr; i++)
		free_untracked(ucd->dirs[i]);
	for (i = 0; i < ucd->untracked_nr; i++)
		free(ucd->untracked[i]);
	free(ucd->untracked);
	free(ucd->dirs);
	free(ucd);
}

void free_untracked_cache(struct untracked_cache *uc)
{
	if (uc)
		free_untracked(uc->root);
	free(uc);
}

struct read_data {
	int index;
	struct untracked_cache_dir **ucd;
	struct ewah_bitmap *check_only;
	struct ewah_bitmap *valid;
	struct ewah_bitmap *sha1_valid;
	const unsigned char *data;
	const unsigned char *end;
};

static void stat_data_from_disk(struct stat_data *to, const unsigned char *data)
{
	memcpy(to, data, sizeof(*to));
	to->sd_ctime.sec  = ntohl(to->sd_ctime.sec);
	to->sd_ctime.nsec = ntohl(to->sd_ctime.nsec);
	to->sd_mtime.sec  = ntohl(to->sd_mtime.sec);
	to->sd_mtime.nsec = ntohl(to->sd_mtime.nsec);
	to->sd_dev	  = ntohl(to->sd_dev);
	to->sd_ino	  = ntohl(to->sd_ino);
	to->sd_uid	  = ntohl(to->sd_uid);
	to->sd_gid	  = ntohl(to->sd_gid);
	to->sd_size	  = ntohl(to->sd_size);
}

static int read_one_dir(struct untracked_cache_dir **untracked_,
			struct read_data *rd)
{
	struct untracked_cache_dir ud, *untracked;
	const unsigned char *data = rd->data, *end = rd->end;
	const unsigned char *eos;
	unsigned int value;
	int i;

	memset(&ud, 0, sizeof(ud));

	value = decode_varint(&data);
	if (data > end)
		return -1;
	ud.recurse	   = 1;
	ud.untracked_alloc = value;
	ud.untracked_nr	   = value;
	if (ud.untracked_nr)
		ALLOC_ARRAY(ud.untracked, ud.untracked_nr);

	ud.dirs_alloc = ud.dirs_nr = decode_varint(&data);
	if (data > end)
		return -1;
	ALLOC_ARRAY(ud.dirs, ud.dirs_nr);

	eos = memchr(data, '\0', end - data);
	if (!eos || eos == end)
		return -1;

	*untracked_ = untracked = xmalloc(st_add3(sizeof(*untracked), eos - data, 1));
	memcpy(untracked, &ud, sizeof(ud));
	memcpy(untracked->name, data, eos - data + 1);
	data = eos + 1;

	for (i = 0; i < untracked->untracked_nr; i++) {
		eos = memchr(data, '\0', end - data);
		if (!eos || eos == end)
			return -1;
		untracked->untracked[i] = xmemdupz(data, eos - data);
		data = eos + 1;
	}

	rd->ucd[rd->index++] = untracked;
	rd->data = data;

	for (i = 0; i < untracked->dirs_nr; i++) {
		if (read_one_dir(untracked->dirs + i, rd) < 0)
			return -1;
	}
	return 0;
}

static void set_check_only(size_t pos, void *cb)
{
	struct read_data *rd = cb;
	struct untracked_cache_dir *ud = rd->ucd[pos];
	ud->check_only = 1;
}

static void read_stat(size_t pos, void *cb)
{
	struct read_data *rd = cb;
	struct untracked_cache_dir *ud = rd->ucd[pos];
	if (rd->data + sizeof(struct stat_data) > rd->end) {
		rd->data = rd->end + 1;
		return;
	}
	stat_data_from_disk(&ud->stat_data, rd->data);
	rd->data += sizeof(struct stat_data);
	ud->valid = 1;
}

static void read_oid(size_t pos, void *cb)
{
	struct read_data *rd = cb;
	struct untracked_cache_dir *ud = rd->ucd[pos];
	if (rd->data + the_hash_algo->rawsz > rd->end) {
		rd->data = rd->end + 1;
		return;
	}
	hashcpy(ud->exclude_oid.hash, rd->data);
	rd->data += the_hash_algo->rawsz;
}

static void load_oid_stat(struct oid_stat *oid_stat, const unsigned char *data,
			  const unsigned char *sha1)
{
	stat_data_from_disk(&oid_stat->stat, data);
	hashcpy(oid_stat->oid.hash, sha1);
	oid_stat->valid = 1;
}

struct untracked_cache *read_untracked_extension(const void *data, unsigned long sz)
{
	struct untracked_cache *uc;
	struct read_data rd;
	const unsigned char *next = data, *end = (const unsigned char *)data + sz;
	const char *ident;
	int ident_len;
	ssize_t len;
	const char *exclude_per_dir;
	const unsigned hashsz = the_hash_algo->rawsz;
	const unsigned offset = sizeof(struct ondisk_untracked_cache);
	const unsigned exclude_per_dir_offset = offset + 2 * hashsz;

	if (sz <= 1 || end[-1] != '\0')
		return NULL;
	end--;

	ident_len = decode_varint(&next);
	if (next + ident_len > end)
		return NULL;
	ident = (const char *)next;
	next += ident_len;

	if (next + exclude_per_dir_offset + 1 > end)
		return NULL;

	uc = xcalloc(1, sizeof(*uc));
	strbuf_init(&uc->ident, ident_len);
	strbuf_add(&uc->ident, ident, ident_len);
	load_oid_stat(&uc->ss_info_exclude,
		      next + ouc_offset(info_exclude_stat),
		      next + offset);
	load_oid_stat(&uc->ss_excludes_file,
		      next + ouc_offset(excludes_file_stat),
		      next + offset + hashsz);
	uc->dir_flags = get_be32(next + ouc_offset(dir_flags));
	exclude_per_dir = (const char *)next + exclude_per_dir_offset;
	uc->exclude_per_dir = xstrdup(exclude_per_dir);
	/* NUL after exclude_per_dir is covered by sizeof(*ouc) */
	next += exclude_per_dir_offset + strlen(exclude_per_dir) + 1;
	if (next >= end)
		goto done2;

	len = decode_varint(&next);
	if (next > end || len == 0)
		goto done2;

	rd.valid      = ewah_new();
	rd.check_only = ewah_new();
	rd.sha1_valid = ewah_new();
	rd.data	      = next;
	rd.end	      = end;
	rd.index      = 0;
	ALLOC_ARRAY(rd.ucd, len);

	if (read_one_dir(&uc->root, &rd) || rd.index != len)
		goto done;

	next = rd.data;
	len = ewah_read_mmap(rd.valid, next, end - next);
	if (len < 0)
		goto done;

	next += len;
	len = ewah_read_mmap(rd.check_only, next, end - next);
	if (len < 0)
		goto done;

	next += len;
	len = ewah_read_mmap(rd.sha1_valid, next, end - next);
	if (len < 0)
		goto done;

	ewah_each_bit(rd.check_only, set_check_only, &rd);
	rd.data = next + len;
	ewah_each_bit(rd.valid, read_stat, &rd);
	ewah_each_bit(rd.sha1_valid, read_oid, &rd);
	next = rd.data;

done:
	free(rd.ucd);
	ewah_free(rd.valid);
	ewah_free(rd.check_only);
	ewah_free(rd.sha1_valid);
done2:
	if (next != end) {
		free_untracked_cache(uc);
		uc = NULL;
	}
	return uc;
}

static void invalidate_one_directory(struct untracked_cache *uc,
				     struct untracked_cache_dir *ucd)
{
	uc->dir_invalidated++;
	ucd->valid = 0;
	ucd->untracked_nr = 0;
}

/*
 * Normally when an entry is added or removed from a directory,
 * invalidating that directory is enough. No need to touch its
 * ancestors. When a directory is shown as "foo/bar/" in git-status
 * however, deleting or adding an entry may have cascading effect.
 *
 * Say the "foo/bar/file" has become untracked, we need to tell the
 * untracked_cache_dir of "foo" that "bar/" is not an untracked
 * directory any more (because "bar" is managed by foo as an untracked
 * "file").
 *
 * Similarly, if "foo/bar/file" moves from untracked to tracked and it
 * was the last untracked entry in the entire "foo", we should show
 * "foo/" instead. Which means we have to invalidate past "bar" up to
 * "foo".
 *
 * This function traverses all directories from root to leaf. If there
 * is a chance of one of the above cases happening, we invalidate back
 * to root. Otherwise we just invalidate the leaf. There may be a more
 * sophisticated way than checking for SHOW_OTHER_DIRECTORIES to
 * detect these cases and avoid unnecessary invalidation, for example,
 * checking for the untracked entry named "bar/" in "foo", but for now
 * stick to something safe and simple.
 */
static int invalidate_one_component(struct untracked_cache *uc,
				    struct untracked_cache_dir *dir,
				    const char *path, int len)
{
	const char *rest = strchr(path, '/');

	if (rest) {
		int component_len = rest - path;
		struct untracked_cache_dir *d =
			lookup_untracked(uc, dir, path, component_len);
		int ret =
			invalidate_one_component(uc, d, rest + 1,
						 len - (component_len + 1));
		if (ret)
			invalidate_one_directory(uc, dir);
		return ret;
	}

	invalidate_one_directory(uc, dir);
	return uc->dir_flags & DIR_SHOW_OTHER_DIRECTORIES;
}

void untracked_cache_invalidate_path(struct index_state *istate,
				     const char *path, int safe_path)
{
	if (!istate->untracked || !istate->untracked->root)
		return;
	if (!safe_path && !verify_path(path, 0))
		return;
	invalidate_one_component(istate->untracked, istate->untracked->root,
				 path, strlen(path));
}

void untracked_cache_remove_from_index(struct index_state *istate,
				       const char *path)
{
	untracked_cache_invalidate_path(istate, path, 1);
}

void untracked_cache_add_to_index(struct index_state *istate,
				  const char *path)
{
	untracked_cache_invalidate_path(istate, path, 1);
}

static void connect_wt_gitdir_in_nested(const char *sub_worktree,
					const char *sub_gitdir)
{
	int i;
	struct repository subrepo;
	struct strbuf sub_wt = STRBUF_INIT;
	struct strbuf sub_gd = STRBUF_INIT;

	const struct submodule *sub;

	/* If the submodule has no working tree, we can ignore it. */
	if (repo_init(&subrepo, sub_gitdir, sub_worktree))
		return;

	if (repo_read_index(&subrepo) < 0)
		die(_("index file corrupt in repo %s"), subrepo.gitdir);

	for (i = 0; i < subrepo.index->cache_nr; i++) {
		const struct cache_entry *ce = subrepo.index->cache[i];

		if (!S_ISGITLINK(ce->ce_mode))
			continue;

		while (i + 1 < subrepo.index->cache_nr &&
		       !strcmp(ce->name, subrepo.index->cache[i + 1]->name))
			/*
			 * Skip entries with the same name in different stages
			 * to make sure an entry is returned only once.
			 */
			i++;

		sub = submodule_from_path(&subrepo, &null_oid, ce->name);
		if (!sub || !is_submodule_active(&subrepo, ce->name))
			/* .gitmodules broken or inactive sub */
			continue;

		strbuf_reset(&sub_wt);
		strbuf_reset(&sub_gd);
		strbuf_addf(&sub_wt, "%s/%s", sub_worktree, sub->path);
		strbuf_addf(&sub_gd, "%s/modules/%s", sub_gitdir, sub->name);

		connect_work_tree_and_git_dir(sub_wt.buf, sub_gd.buf, 1);
	}
	strbuf_release(&sub_wt);
	strbuf_release(&sub_gd);
	repo_clear(&subrepo);
}

void connect_work_tree_and_git_dir(const char *work_tree_,
				   const char *git_dir_,
				   int recurse_into_nested)
{
	struct strbuf gitfile_sb = STRBUF_INIT;
	struct strbuf cfg_sb = STRBUF_INIT;
	struct strbuf rel_path = STRBUF_INIT;
	char *git_dir, *work_tree;

	/* Prepare .git file */
	strbuf_addf(&gitfile_sb, "%s/.git", work_tree_);
	if (safe_create_leading_directories_const(gitfile_sb.buf))
		die(_("could not create directories for %s"), gitfile_sb.buf);

	/* Prepare config file */
	strbuf_addf(&cfg_sb, "%s/config", git_dir_);
	if (safe_create_leading_directories_const(cfg_sb.buf))
		die(_("could not create directories for %s"), cfg_sb.buf);

	git_dir = real_pathdup(git_dir_, 1);
	work_tree = real_pathdup(work_tree_, 1);

	/* Write .git file */
	write_file(gitfile_sb.buf, "gitdir: %s",
		   relative_path(git_dir, work_tree, &rel_path));
	/* Update core.worktree setting */
	git_config_set_in_file(cfg_sb.buf, "core.worktree",
			       relative_path(work_tree, git_dir, &rel_path));

	strbuf_release(&gitfile_sb);
	strbuf_release(&cfg_sb);
	strbuf_release(&rel_path);

	if (recurse_into_nested)
		connect_wt_gitdir_in_nested(work_tree, git_dir);

	free(work_tree);
	free(git_dir);
}

/*
 * Migrate the git directory of the given path from old_git_dir to new_git_dir.
 */
void relocate_gitdir(const char *path, const char *old_git_dir, const char *new_git_dir)
{
	if (rename(old_git_dir, new_git_dir) < 0)
		die_errno(_("could not migrate git directory from '%s' to '%s'"),
			old_git_dir, new_git_dir);

	connect_work_tree_and_git_dir(path, new_git_dir, 0);
}