git/read-index.c

   1 #include <stdio.h>
   2 #include <unistd.h>
   3 #include <fcntl.h>
   4 #include <stdlib.h>
   5 #include <sys/types.h>
   6 #include <sys/stat.h>
   7 #include <sys/mman.h>
   8 #include <arpa/inet.h>
   9
  10 #ifndef FLEX_ARRAY
  11 #if defined(__GNUC__) && (__GNUC__ < 3)
  12 #define FLEX_ARRAY 0
  13 #else
  14 #define FLEX_ARRAY /* empty */
  15 #endif
  16 #endif
  17
  18 struct cache_header {
  19         unsigned int hdr_signature;
  20         unsigned int hdr_version;
  21         unsigned int hdr_entries;
  22 };
  23
  24 struct cache_time {
  25         unsigned int sec;
  26         unsigned int nsec;
  27 };
  28
  29 struct cache_entry {
  30         struct cache_time ce_ctime;
  31         struct cache_time ce_mtime;
  32         unsigned int ce_dev;
  33         unsigned int ce_ino;
  34         unsigned int ce_mode;
  35         unsigned int ce_uid;
  36         unsigned int ce_gid;
  37         unsigned int ce_size;
  38         unsigned char sha1[20];
  39         unsigned short ce_flags;
  40         char name[FLEX_ARRAY]; /* more */
  41 };
  42
  43 #define CE_NAMEMASK  (0x0fff)
  44
  45 #define offsetof(type, member)  __builtin_offsetof (type, member)
  46 #define cache_entry_size(len) ((offsetof(struct cache_entry,name) + (len) + 8) & ~7)
  47 #define ce_namelen(ce) (CE_NAMEMASK & ntohs((ce)->ce_flags))
  48 #define ce_size(ce) cache_entry_size(ce_namelen(ce))
  49
  50 int main(int argc, char *argv[])
  51 {
  52         void *index;
  53         size_t offset;
  54         int i, err, fd;
  55         struct stat buf;
  56         unsigned int active_nr;
  57         struct cache_header *hdr;
  58
  59         if (argc != 2) {
  60                 printf("usage: %s: <index-file>\n", argv[0]);
  61                 exit(1);
  62         }
  63
  64         fd = open(argv[1], O_RDONLY);
  65         if (fd < 0) {
  66                 perror("open()");
  67                 exit(1);
  68         }
  69
  70         err = fstat(fd, &buf);
  71         if (err) {
  72                 perror("fstat()");
  73                 exit(1);
  74         }
  75
  76         index = mmap(NULL, buf.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
  77         if (index == MAP_FAILED) {
  78                 perror("mmap()");
  79                 exit(1);
  80         }
  81         close(fd);
  82
  83         hdr = index;
  84         active_nr = ntohl(hdr->hdr_entries);
  85         printf("Number of entries: %d\n\n", active_nr);
  86         printf("SHA1       file name\n");
  87         printf("----       ---------\n");
  88         offset = sizeof(*hdr);
  89         for (i = 0; i < active_nr; i++) {
  90                 struct cache_entry *ce;
  91
  92                 ce = (struct cache_entry *) ((char *) index + offset);
  93                 printf("%#x %s\n", ce->sha1, ce->name);
  94
  95                 offset = offset + ce_size(ce);
  96         }
  97
  98         munmap(index, buf.st_size);
  99         return 0;
 100 }