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