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) ? 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)
  69 {
  70         int fd;
  71         void *new;
  72         unsigned long size;
  73         long wrote;
  74         char type[20];
  75
  76         new = read_sha1_file(ce->sha1, type, &size);
  77         if (!new || strcmp(type, "blob")) {
  78                 return error("checkout-cache: unable to read sha1 file of %s (%s)",
  79                         ce->name, sha1_to_hex(ce->sha1));
  80         }
  81         fd = create_file(ce->name, ntohl(ce->ce_mode));
  82         if (fd < 0) {
  83                 free(new);
  84                 return error("checkout-cache: unable to create %s (%s)",
  85                         ce->name, strerror(errno));
  86         }
  87         wrote = write(fd, new, size);
  88         close(fd);
  89         free(new);
  90         if (wrote != size)
  91                 return error("checkout-cache: unable to write %s", ce->name);
  92         return 0;
  93 }
  94
  95 static int checkout_entry(struct cache_entry *ce)
  96 {
  97         struct stat st;
  98
  99         if (!stat(ce->name, &st)) {
 100                 unsigned changed = cache_match_stat(ce, &st);
 101                 if (!changed)
 102                         return 0;
 103                 if (!force) {
 104                         if (!quiet)
 105                                 fprintf(stderr, "checkout-cache: %s already exists\n", ce->name);
 106                         return 0;
 107                 }
 108
 109                 /*
 110                  * We unlink the old file, to get the new one with the
 111                  * right permissions (including umask, which is nasty
 112                  * to emulate by hand - much easier to let the system
 113                  * just do the right thing)
 114                  */
 115                 unlink(ce->name);
 116         }
 117         return write_entry(ce);
 118 }
 119
 120 static int checkout_file(const char *name)
 121 {
 122         int pos = cache_name_pos(name, strlen(name));
 123         if (pos < 0) {
 124                 if (!quiet) {
 125                         pos = -pos - 1;
 126                         fprintf(stderr,
 127                                 "checkout-cache: %s is %s.\n",
 128                                 name,
 129                                 (pos < active_nr &&
 130                                  !strcmp(active_cache[pos]->name, name)) ?
 131                                 "unmerged" : "not in the cache");
 132                 }
 133                 return -1;
 134         }
 135         return checkout_entry(active_cache[pos]);
 136 }
 137
 138 static int checkout_all(void)
 139 {
 140         int i;
 141
 142         for (i = 0; i < active_nr ; i++) {
 143                 struct cache_entry *ce = active_cache[i];
 144                 if (checkout_entry(ce) < 0)
 145                         return -1;
 146         }
 147         return 0;
 148 }
 149
 150 int main(int argc, char **argv)
 151 {
 152         int i, force_filename = 0;
 153
 154         if (read_cache() < 0) {
 155                 die("invalid cache");
 156         }
 157
 158         for (i = 1; i < argc; i++) {
 159                 const char *arg = argv[i];
 160                 if (!force_filename) {
 161                         if (!strcmp(arg, "-a")) {
 162                                 checkout_all();
 163                                 continue;
 164                         }
 165                         if (!strcmp(arg, "--")) {
 166                                 force_filename = 1;
 167                                 continue;
 168                         }
 169                         if (!strcmp(arg, "-f")) {
 170                                 force = 1;
 171                                 continue;
 172                         }
 173                         if (!strcmp(arg, "-q")) {
 174                                 quiet = 1;
 175                                 continue;
 176                         }
 177                 }
 178                 checkout_file(arg);
 179         }
 180         return 0;
 181 }