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  *      git-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 "git-checkout-cache" does nothing. You probably
  16  * meant "git-checkout-cache -a". And if you want to force it, you
  17  * want "git-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 git-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 <sys/types.h>
  36 #include <dirent.h>
  37 #include "cache.h"
  38
  39 static int force = 0, quiet = 0, not_new = 0, refresh_cache = 0;
  40 static const char *base_dir = "";
  41 static int base_dir_len = 0;
  42
  43 static void create_directories(const char *path)
  44 {
  45         int len = strlen(path);
  46         char *buf = xmalloc(len + 1);
  47         const char *slash = path;
  48
  49         while ((slash = strchr(slash+1, '/')) != NULL) {
  50                 len = slash - path;
  51                 memcpy(buf, path, len);
  52                 buf[len] = 0;
  53                 if (mkdir(buf, 0755)) {
  54                         if (errno == EEXIST) {
  55                                 struct stat st;
  56                                 if (len > base_dir_len && force && !unlink(buf) && !mkdir(buf, 0755))
  57                                         continue;
  58                                 if (!stat(buf, &st) && S_ISDIR(st.st_mode))
  59                                         continue; /* ok */
  60                         }
  61                         die("cannot create directory at %s", buf);
  62                 }
  63         }
  64         free(buf);
  65 }
  66
  67 static void remove_subtree(const char *path)
  68 {
  69         DIR *dir = opendir(path);
  70         struct dirent *de;
  71         char pathbuf[PATH_MAX];
  72         char *name;
  73
  74         if (!dir)
  75                 die("cannot opendir %s", path);
  76         strcpy(pathbuf, path);
  77         name = pathbuf + strlen(path);
  78         *name++ = '/';
  79         while ((de = readdir(dir)) != NULL) {
  80                 struct stat st;
  81                 if ((de->d_name[0] == '.') &&
  82                     ((de->d_name[1] == 0) ||
  83                      ((de->d_name[1] == '.') && de->d_name[2] == 0)))
  84                         continue;
  85                 strcpy(name, de->d_name);
  86                 if (lstat(pathbuf, &st))
  87                         die("cannot lstat %s", pathbuf);
  88                 if (S_ISDIR(st.st_mode))
  89                         remove_subtree(pathbuf);
  90                 else if (unlink(pathbuf))
  91                         die("cannot unlink %s", pathbuf);
  92         }
  93         closedir(dir);
  94         if (rmdir(path))
  95                 die("cannot rmdir %s", path);
  96 }
  97
  98 static int create_file(const char *path, unsigned int mode)
  99 {
 100         int fd;
 101
 102         mode = (mode & 0100) ? 0777 : 0666;
 103         create_directories(path);
 104         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 105         if (fd < 0) {
 106                 if (errno == EISDIR && force) {
 107                         remove_subtree(path);
 108                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 109                 }
 110         }
 111         return fd;
 112 }
 113
 114 static int write_entry(struct cache_entry *ce, const char *path)
 115 {
 116         int fd;
 117         void *new;
 118         unsigned long size;
 119         long wrote;
 120         char type[20];
 121         char target[1024];
 122
 123         new = read_sha1_file(ce->sha1, type, &size);
 124         if (!new || strcmp(type, "blob")) {
 125                 if (new)
 126                         free(new);
 127                 return error("git-checkout-cache: unable to read sha1 file of %s (%s)",
 128                         path, sha1_to_hex(ce->sha1));
 129         }
 130         switch (ntohl(ce->ce_mode) & S_IFMT) {
 131         case S_IFREG:
 132                 fd = create_file(path, ntohl(ce->ce_mode));
 133                 if (fd < 0) {
 134                         free(new);
 135                         return error("git-checkout-cache: unable to create file %s (%s)",
 136                                 path, strerror(errno));
 137                 }
 138                 wrote = write(fd, new, size);
 139                 close(fd);
 140                 free(new);
 141                 if (wrote != size)
 142                         return error("git-checkout-cache: unable to write file %s", path);
 143                 break;
 144         case S_IFLNK:
 145                 memcpy(target, new, size);
 146                 target[size] = '\0';
 147                 create_directories(path);
 148                 if (symlink(target, path)) {
 149                         free(new);
 150                         return error("git-checkout-cache: unable to create symlink %s (%s)",
 151                                 path, strerror(errno));
 152                 }
 153                 free(new);
 154                 break;
 155         default:
 156                 free(new);
 157                 return error("git-checkout-cache: unknown file mode for %s", path);
 158         }
 159
 160         if (refresh_cache) {
 161                 struct stat st;
 162                 lstat(ce->name, &st);
 163                 fill_stat_cache_info(ce, &st);
 164         }
 165         return 0;
 166 }
 167
 168 static int checkout_entry(struct cache_entry *ce)
 169 {
 170         struct stat st;
 171         static char path[MAXPATHLEN+1];
 172         int len = base_dir_len;
 173
 174         memcpy(path, base_dir, len);
 175         strcpy(path + len, ce->name);
 176
 177         if (!lstat(path, &st)) {
 178                 unsigned changed = ce_match_stat(ce, &st);
 179                 if (!changed)
 180                         return 0;
 181                 if (!force) {
 182                         if (!quiet)
 183                                 fprintf(stderr, "git-checkout-cache: %s already exists\n", path);
 184                         return 0;
 185                 }
 186
 187                 /*
 188                  * We unlink the old file, to get the new one with the
 189                  * right permissions (including umask, which is nasty
 190                  * to emulate by hand - much easier to let the system
 191                  * just do the right thing)
 192                  */
 193                 unlink(path);
 194         } else if (not_new)
 195                 return 0;
 196         return write_entry(ce, path);
 197 }
 198
 199 static int checkout_file(const char *name)
 200 {
 201         int pos = cache_name_pos(name, strlen(name));
 202         if (pos < 0) {
 203                 if (!quiet) {
 204                         pos = -pos - 1;
 205                         fprintf(stderr,
 206                                 "git-checkout-cache: %s is %s.\n",
 207                                 name,
 208                                 (pos < active_nr &&
 209                                  !strcmp(active_cache[pos]->name, name)) ?
 210                                 "unmerged" : "not in the cache");
 211                 }
 212                 return -1;
 213         }
 214         return checkout_entry(active_cache[pos]);
 215 }
 216
 217 static int checkout_all(void)
 218 {
 219         int i;
 220
 221         for (i = 0; i < active_nr ; i++) {
 222                 struct cache_entry *ce = active_cache[i];
 223                 if (ce_stage(ce))
 224                         continue;
 225                 if (checkout_entry(ce) < 0)
 226                         return -1;
 227         }
 228         return 0;
 229 }
 230
 231 int main(int argc, char **argv)
 232 {
 233         int i, force_filename = 0;
 234         struct cache_file cache_file;
 235         int newfd = -1;
 236
 237         if (read_cache() < 0) {
 238                 die("invalid cache");
 239         }
 240
 241         for (i = 1; i < argc; i++) {
 242                 const char *arg = argv[i];
 243                 if (!force_filename) {
 244                         if (!strcmp(arg, "-a")) {
 245                                 checkout_all();
 246                                 continue;
 247                         }
 248                         if (!strcmp(arg, "--")) {
 249                                 force_filename = 1;
 250                                 continue;
 251                         }
 252                         if (!strcmp(arg, "-f")) {
 253                                 force = 1;
 254                                 continue;
 255                         }
 256                         if (!strcmp(arg, "-q")) {
 257                                 quiet = 1;
 258                                 continue;
 259                         }
 260                         if (!strcmp(arg, "-n")) {
 261                                 not_new = 1;
 262                                 continue;
 263                         }
 264                         if (!strcmp(arg, "-u")) {
 265                                 refresh_cache = 1;
 266                                 if (newfd < 0)
 267                                         newfd = hold_index_file_for_update
 268                                                 (&cache_file,
 269                                                  get_index_file());
 270                                 if (newfd < 0)
 271                                         die("cannot open index.lock file.");
 272                                 continue;
 273                         }
 274                         if (!memcmp(arg, "--prefix=", 9)) {
 275                                 base_dir = arg+9;
 276                                 base_dir_len = strlen(base_dir);
 277                                 continue;
 278                         }
 279                 }
 280                 if (base_dir_len) {
 281                         /* when --prefix is specified we do not
 282                          * want to update cache.
 283                          */
 284                         if (refresh_cache) {
 285                                 close(newfd); newfd = -1;
 286                                 rollback_index_file(&cache_file);
 287                         }
 288                         refresh_cache = 0;
 289                 }
 290                 checkout_file(arg);
 291         }
 292
 293         if (0 <= newfd &&
 294             (write_cache(newfd, active_cache, active_nr) ||
 295              commit_index_file(&cache_file)))
 296                 die("Unable to write new cachefile");
 297         return 0;
 298 }