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 void create_directories(const char *path)
  40 {
  41         int len = strlen(path);
  42         char *buf = malloc(len + 1);
  43         const char *slash = path;
  44
  45         while ((slash = strchr(slash+1, '/')) != NULL) {
  46                 len = slash - path;
  47                 memcpy(buf, path, len);
  48                 buf[len] = 0;
  49                 mkdir(buf, 0755);
  50         }
  51 }
  52
  53 static int create_file(const char *path, unsigned int mode)
  54 {
  55         int fd;
  56
  57         mode = (mode & 0100) ? 777 : 666;
  58         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
  59         if (fd < 0) {
  60                 if (errno == ENOENT) {
  61                         create_directories(path);
  62                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
  63                 }
  64         }
  65         if (fd >= 0)
  66                 fchmod(fd, mode);
  67         return fd;
  68 }
  69
  70 static int write_entry(struct cache_entry *ce)
  71 {
  72         int fd;
  73         void *new;
  74         unsigned long size;
  75         long wrote;
  76         char type[20];
  77
  78         new = read_sha1_file(ce->sha1, type, &size);
  79         if (!new || strcmp(type, "blob")) {
  80                 return error("checkout-cache: unable to read sha1 file of %s (%s)",
  81                         ce->name, sha1_to_hex(ce->sha1));
  82         }
  83         fd = create_file(ce->name, ntohl(ce->ce_mode));
  84         if (fd < 0) {
  85                 free(new);
  86                 return error("checkout-cache: unable to create %s (%s)",
  87                         ce->name, strerror(errno));
  88         }
  89         wrote = write(fd, new, size);
  90         close(fd);
  91         free(new);
  92         if (wrote != size)
  93                 return error("checkout-cache: unable to write %s", ce->name);
  94         return 0;
  95 }
  96
  97 static int checkout_entry(struct cache_entry *ce)
  98 {
  99         struct stat st;
 100
 101         if (!stat(ce->name, &st)) {
 102                 unsigned changed = cache_match_stat(ce, &st);
 103                 if (!changed)
 104                         return 0;
 105                 if (!force) {
 106                         if (!quiet)
 107                                 fprintf(stderr, "checkout-cache: %s already exists\n", ce->name);
 108                         return 0;
 109                 }
 110
 111                 /*
 112                  * We unlink the old file, to get the new one with the
 113                  * right permissions (including umask, which is nasty
 114                  * to emulate by hand - much easier to let the system
 115                  * just do the right thing)
 116                  */
 117                 unlink(ce->name);
 118         }
 119         return write_entry(ce);
 120 }
 121
 122 static int checkout_file(const char *name)
 123 {
 124         int pos = cache_name_pos(name, strlen(name));
 125         if (pos < 0) {
 126                 if (!quiet)
 127                         fprintf(stderr, "checkout-cache: %s is not in the cache\n", name);
 128                 return -1;
 129         }
 130         return checkout_entry(active_cache[pos]);
 131 }
 132
 133 static int checkout_all(void)
 134 {
 135         int i;
 136
 137         for (i = 0; i < active_nr ; i++) {
 138                 struct cache_entry *ce = active_cache[i];
 139                 if (checkout_entry(ce) < 0)
 140                         return -1;
 141         }
 142         return 0;
 143 }
 144
 145 int main(int argc, char **argv)
 146 {
 147         int i, force_filename = 0;
 148
 149         if (read_cache() < 0) {
 150                 die("invalid cache");
 151         }
 152
 153         for (i = 1; i < argc; i++) {
 154                 const char *arg = argv[i];
 155                 if (!force_filename) {
 156                         if (!strcmp(arg, "-a")) {
 157                                 checkout_all();
 158                                 continue;
 159                         }
 160                         if (!strcmp(arg, "--")) {
 161                                 force_filename = 1;
 162                                 continue;
 163                         }
 164                         if (!strcmp(arg, "-f")) {
 165                                 force = 1;
 166                                 continue;
 167                         }
 168                         if (!strcmp(arg, "-q")) {
 169                                 quiet = 1;
 170                                 continue;
 171                         }
 172                 }
 173                 checkout_file(arg);
 174         }
 175         return 0;
 176 }