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, not_new = 0;
  38
  39 static void create_directories(const char *path)
  40 {
  41         int len = strlen(path);
  42         char *buf = xmalloc(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) ? 0777 : 0666;
  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         return fd;
  66 }
  67
  68 static int write_entry(struct cache_entry *ce, const char *path)
  69 {
  70         int fd;
  71         void *new;
  72         unsigned long size;
  73         long wrote;
  74         char type[20];
  75         char target[1024];
  76
  77         new = read_sha1_file(ce->sha1, type, &size);
  78         if (!new || strcmp(type, "blob")) {
  79                 return error("checkout-cache: unable to read sha1 file of %s (%s)",
  80                         path, sha1_to_hex(ce->sha1));
  81         }
  82         switch (ntohl(ce->ce_mode) & S_IFMT) {
  83         case S_IFREG:
  84                 fd = create_file(path, ntohl(ce->ce_mode));
  85                 if (fd < 0) {
  86                         free(new);
  87                         return error("checkout-cache: unable to create file %s (%s)",
  88                                 path, strerror(errno));
  89                 }
  90                 wrote = write(fd, new, size);
  91                 close(fd);
  92                 free(new);
  93                 if (wrote != size)
  94                         return error("checkout-cache: unable to write file %s", path);
  95                 break;
  96         case S_IFLNK:
  97                 memcpy(target, new, size);
  98                 target[size] = '\0';
  99                 if (symlink(target, path)) {
 100                         free(new);
 101                         return error("checkout-cache: unable to create symlink %s (%s)",
 102                                 path, strerror(errno));
 103                 }
 104                 free(new);
 105                 break;
 106         default:
 107                 free(new);
 108                 return error("checkout-cache: unknown file mode for %s", path);
 109         }
 110         return 0;
 111 }
 112
 113 static int checkout_entry(struct cache_entry *ce, const char *base_dir)
 114 {
 115         struct stat st;
 116         static char path[MAXPATHLEN+1];
 117         int len = strlen(base_dir);
 118
 119         memcpy(path, base_dir, len);
 120         strcpy(path + len, ce->name);
 121
 122         if (!lstat(path, &st)) {
 123                 unsigned changed = cache_match_stat(ce, &st);
 124                 if (!changed)
 125                         return 0;
 126                 if (!force) {
 127                         if (!quiet)
 128                                 fprintf(stderr, "checkout-cache: %s already exists\n", path);
 129                         return 0;
 130                 }
 131
 132                 /*
 133                  * We unlink the old file, to get the new one with the
 134                  * right permissions (including umask, which is nasty
 135                  * to emulate by hand - much easier to let the system
 136                  * just do the right thing)
 137                  */
 138                 unlink(path);
 139         } else if (not_new)
 140                 return 0;
 141         return write_entry(ce, path);
 142 }
 143
 144 static int checkout_file(const char *name, const char *base_dir)
 145 {
 146         int pos = cache_name_pos(name, strlen(name));
 147         if (pos < 0) {
 148                 if (!quiet) {
 149                         pos = -pos - 1;
 150                         fprintf(stderr,
 151                                 "checkout-cache: %s is %s.\n",
 152                                 name,
 153                                 (pos < active_nr &&
 154                                  !strcmp(active_cache[pos]->name, name)) ?
 155                                 "unmerged" : "not in the cache");
 156                 }
 157                 return -1;
 158         }
 159         return checkout_entry(active_cache[pos], base_dir);
 160 }
 161
 162 static int checkout_all(const char *base_dir)
 163 {
 164         int i;
 165
 166         for (i = 0; i < active_nr ; i++) {
 167                 struct cache_entry *ce = active_cache[i];
 168                 if (ce_stage(ce))
 169                         continue;
 170                 if (checkout_entry(ce, base_dir) < 0)
 171                         return -1;
 172         }
 173         return 0;
 174 }
 175
 176 int main(int argc, char **argv)
 177 {
 178         int i, force_filename = 0;
 179         const char *base_dir = "";
 180
 181         if (read_cache() < 0) {
 182                 die("invalid cache");
 183         }
 184
 185         for (i = 1; i < argc; i++) {
 186                 const char *arg = argv[i];
 187                 if (!force_filename) {
 188                         if (!strcmp(arg, "-a")) {
 189                                 checkout_all(base_dir);
 190                                 continue;
 191                         }
 192                         if (!strcmp(arg, "--")) {
 193                                 force_filename = 1;
 194                                 continue;
 195                         }
 196                         if (!strcmp(arg, "-f")) {
 197                                 force = 1;
 198                                 continue;
 199                         }
 200                         if (!strcmp(arg, "-q")) {
 201                                 quiet = 1;
 202                                 continue;
 203                         }
 204                         if (!strcmp(arg, "-n")) {
 205                                 not_new = 1;
 206                                 continue;
 207                         }
 208                         if (!memcmp(arg, "--prefix=", 9)) {
 209                                 base_dir = arg+9;
 210                                 continue;
 211                         }
 212                 }
 213                 checkout_file(arg, base_dir);
 214         }
 215         return 0;
 216 }