checkout-cache.c

   1 /*
   2  * Check-out files from the "current cache directory"
   3  *
   4  * Copyright (C) 2005 Linus Torvalds
   5  *
   6  * Careful: order of argument flags does matter. For example,
   7  *
   8  *      checkout-cache -a -f file.c
   9  *
  10  * Will first check out all files listed in the cache (but not
  11  * overwrite any old ones), and then force-checkout "file.c" a
  12  * second time (ie that one _will_ overwrite any old contents
  13  * with the same filename).
  14  *
  15  * Also, just doing "checkout-cache" does nothing. You probably
  16  * meant "checkout-cache -a". And if you want to force it, you
  17  * want "checkout-cache -f -a".
  18  *
  19  * Intuitiveness is not the goal here. Repeatability is. The
  20  * reason for the "no arguments means no work" thing is that
  21  * from scripts you are supposed to be able to do things like
  22  *
  23  *      find . -name '*.h' -print0 | xargs -0 checkout-cache -f --
  24  *
  25  * which will force all existing *.h files to be replaced with
  26  * their cached copies. If an empty command line implied "all",
  27  * then this would force-refresh everything in the cache, which
  28  * was not the point.
  29  *
  30  * Oh, and the "--" is just a good idea when you know the rest
  31  * will be filenames. Just so that you wouldn't have a filename
  32  * of "-a" causing problems (not possible in the above example,
  33  * but get used to it in scripting!).
  34  */
  35 #include "cache.h"
  36
  37 static int force = 0, quiet = 0;
  38
  39 static int write_entry(struct cache_entry *ce)
  40 {
  41         int fd;
  42         void *new;
  43         unsigned long size;
  44         long wrote;
  45
  46         new = read_sha1_file(ce->sha1, "blob", &size);
  47         if (!new) {
  48                 fprintf(stderr, "checkout-cache: unable to read sha1 file of %s (%s)",
  49                         ce->name, sha1_to_hex(ce->sha1));
  50                 return -1;
  51         }
  52         fd = open(ce->name, O_WRONLY | O_CREAT | O_TRUNC, 0600);
  53         if (fd < 0) {
  54                 fprintf(stderr, "checkout-cache: unable to create %s (%s)",
  55                         ce->name, strerror(errno));
  56                 free(new);
  57                 return -1;
  58         }
  59         wrote = write(fd, new, size);
  60         close(fd);
  61         free(new);
  62         if (wrote == size)
  63                 return 0;
  64         fprintf(stderr, "checkout-cache: unable to write %s", ce->name);
  65         return -1;
  66 }
  67
  68 static int checkout_entry(struct cache_entry *ce)
  69 {
  70         if (!force) {
  71                 struct stat st;
  72
  73                 if (!stat(ce->name, &st)) {
  74                         unsigned changed = cache_match_stat(ce, &st);
  75                         if (!changed)
  76                                 return 0;
  77                         if (!quiet)
  78                                 fprintf(stderr, "checkout-cache: %s already exists", ce->name);
  79                         return -1;
  80                 }
  81         }
  82         return write_entry(ce);
  83 }
  84
  85 static int checkout_file(const char *name)
  86 {
  87         int pos = cache_name_pos(name, strlen(name));
  88         if (pos < 0) {
  89                 if (!quiet)
  90                         fprintf(stderr, "checkout-cache: %s is not in the cache", name);
  91                 return -1;
  92         }
  93         return checkout_entry(active_cache[pos]);
  94 }
  95
  96 static int checkout_all(void)
  97 {
  98         int i;
  99
 100         for (i = 0; i < active_nr ; i++) {
 101                 struct cache_entry *ce = active_cache[i];
 102                 if (checkout_entry(ce) < 0)
 103                         return -1;
 104         }
 105         return 0;
 106 }
 107
 108 int main(int argc, char **argv)
 109 {
 110         int i, force_filename = 0;
 111
 112         if (read_cache() < 0) {
 113                 fprintf(stderr, "Invalid cache");
 114                 exit(1);
 115         }
 116
 117         for (i = 1; i < argc; i++) {
 118                 const char *arg = argv[i];
 119                 if (!force_filename) {
 120                         if (!strcmp(arg, "-a")) {
 121                                 checkout_all();
 122                                 continue;
 123                         }
 124                         if (!strcmp(arg, "--")) {
 125                                 force_filename = 1;
 126                                 continue;
 127                         }
 128                         if (!strcmp(arg, "-f")) {
 129                                 force = 1;
 130                                 continue;
 131                         }
 132                         if (!strcmp(arg, "-q")) {
 133                                 quiet = 1;
 134                                 continue;
 135                         }
 136                 }
 137                 checkout_file(arg);
 138         }
 139         return 0;
 140 }