Andrew's git - gitweb.git/blob

   1/*
   2 * GIT - The information manager from hell
   3 *
   4 * Copyright (C) Linus Torvalds, 2005
   5 */
   6#include "cache.h"
   7
   8/*
   9 * Default to not allowing changes to the list of files. The
  10 * tool doesn't actually care, but this makes it harder to add
  11 * files to the revision control by mistake by doing something
  12 * like "update-cache *" and suddenly having all the object
  13 * files be revision controlled.
  14 */
  15static int allow_add = 0, allow_remove = 0;
  16
  17static int index_fd(const char *path, int namelen, struct cache_entry *ce, int fd, struct stat *st)
  18{
  19        z_stream stream;
  20        unsigned long size = st->st_size;
  21        int max_out_bytes = namelen + size + 200;
  22        void *out = malloc(max_out_bytes);
  23        void *metadata = malloc(namelen + 200);
  24        void *in;
  25        SHA_CTX c;
  26
  27        in = "";
  28        if (size)
  29                in = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
  30        close(fd);
  31        if (!out || (int)(long)in == -1)
  32                return -1;
  33
  34        memset(&stream, 0, sizeof(stream));
  35        deflateInit(&stream, Z_BEST_COMPRESSION);
  36
  37        /*
  38         * ASCII size + nul byte
  39         */     
  40        stream.next_in = metadata;
  41        stream.avail_in = 1+sprintf(metadata, "blob %lu", size);
  42        stream.next_out = out;
  43        stream.avail_out = max_out_bytes;
  44        while (deflate(&stream, 0) == Z_OK)
  45                /* nothing */;
  46
  47        /*
  48         * File content
  49         */
  50        stream.next_in = in;
  51        stream.avail_in = size;
  52        while (deflate(&stream, Z_FINISH) == Z_OK)
  53                /*nothing */;
  54
  55        deflateEnd(&stream);
  56        
  57        SHA1_Init(&c);
  58        SHA1_Update(&c, out, stream.total_out);
  59        SHA1_Final(ce->sha1, &c);
  60
  61        return write_sha1_buffer(ce->sha1, out, stream.total_out);
  62}
  63
  64/*
  65 * This only updates the "non-critical" parts of the directory
  66 * cache, ie the parts that aren't tracked by GIT, and only used
  67 * to validate the cache.
  68 */
  69static void fill_stat_cache_info(struct cache_entry *ce, struct stat *st)
  70{
  71        ce->ctime.sec = st->st_ctime;
  72#ifdef NSEC
  73        ce->ctime.nsec = st->st_ctim.tv_nsec;
  74#endif
  75        ce->mtime.sec = st->st_mtime;
  76#ifdef NSEC
  77        ce->mtime.nsec = st->st_mtim.tv_nsec;
  78#endif
  79        ce->st_dev = st->st_dev;
  80        ce->st_ino = st->st_ino;
  81        ce->st_uid = st->st_uid;
  82        ce->st_gid = st->st_gid;
  83}
  84
  85static int add_file_to_cache(char *path)
  86{
  87        int size, namelen;
  88        struct cache_entry *ce;
  89        struct stat st;
  90        int fd;
  91
  92        fd = open(path, O_RDONLY);
  93        if (fd < 0) {
  94                if (errno == ENOENT) {
  95                        if (allow_remove)
  96                                return remove_file_from_cache(path);
  97                }
  98                return -1;
  99        }
 100        if (fstat(fd, &st) < 0) {
 101                close(fd);
 102                return -1;
 103        }
 104        namelen = strlen(path);
 105        size = cache_entry_size(namelen);
 106        ce = malloc(size);
 107        memset(ce, 0, size);
 108        memcpy(ce->name, path, namelen);
 109        fill_stat_cache_info(ce, &st);
 110        ce->st_mode = st.st_mode;
 111        ce->st_size = st.st_size;
 112        ce->namelen = namelen;
 113
 114        if (index_fd(path, namelen, ce, fd, &st) < 0)
 115                return -1;
 116
 117        return add_cache_entry(ce, allow_add);
 118}
 119
 120static int match_data(int fd, void *buffer, unsigned long size)
 121{
 122        while (size) {
 123                char compare[1024];
 124                int ret = read(fd, compare, sizeof(compare));
 125
 126                if (ret <= 0 || ret > size || memcmp(buffer, compare, ret))
 127                        return -1;
 128                size -= ret;
 129                buffer += ret;
 130        }
 131        return 0;
 132}
 133
 134static int compare_data(struct cache_entry *ce, unsigned long expected_size)
 135{
 136        int match = -1;
 137        int fd = open(ce->name, O_RDONLY);
 138
 139        if (fd >= 0) {
 140                void *buffer;
 141                unsigned long size;
 142                char type[10];
 143
 144                buffer = read_sha1_file(ce->sha1, type, &size);
 145                if (buffer) {
 146                        if (size == expected_size && !strcmp(type, "blob"))
 147                                match = match_data(fd, buffer, size);
 148                        free(buffer);
 149                }
 150                close(fd);
 151        }
 152        return match;
 153}
 154
 155/*
 156 * "refresh" does not calculate a new sha1 file or bring the
 157 * cache up-to-date for mode/content changes. But what it
 158 * _does_ do is to "re-match" the stat information of a file
 159 * with the cache, so that you can refresh the cache for a
 160 * file that hasn't been changed but where the stat entry is
 161 * out of date.
 162 *
 163 * For example, you'd want to do this after doing a "read-tree",
 164 * to link up the stat cache details with the proper files.
 165 */
 166static struct cache_entry *refresh_entry(struct cache_entry *ce)
 167{
 168        struct stat st;
 169        struct cache_entry *updated;
 170        int changed, size;
 171
 172        if (stat(ce->name, &st) < 0)
 173                return NULL;
 174
 175        changed = cache_match_stat(ce, &st);
 176        if (!changed)
 177                return ce;
 178
 179        /*
 180         * If the mode has changed, there's no point in trying
 181         * to refresh the entry - it's not going to match
 182         */
 183        if (changed & MODE_CHANGED)
 184                return NULL;
 185
 186        if (compare_data(ce, st.st_size))
 187                return NULL;
 188
 189        size = ce_size(ce);
 190        updated = malloc(size);
 191        memcpy(updated, ce, size);
 192        fill_stat_cache_info(updated, &st);
 193        updated->st_size = st.st_size;
 194        return updated;
 195}
 196
 197static void refresh_cache(void)
 198{
 199        int i;
 200
 201        for (i = 0; i < active_nr; i++) {
 202                struct cache_entry *ce = active_cache[i];
 203                struct cache_entry *new = refresh_entry(ce);
 204
 205                if (!new) {
 206                        printf("%s: needs update\n", ce->name);
 207                        continue;
 208                }
 209                active_cache[i] = new;
 210        }
 211}
 212
 213/*
 214 * We fundamentally don't like some paths: we don't want
 215 * dot or dot-dot anywhere, and in fact, we don't even want
 216 * any other dot-files (.git or anything else). They
 217 * are hidden, for chist sake.
 218 *
 219 * Also, we don't want double slashes or slashes at the
 220 * end that can make pathnames ambiguous.
 221 */
 222static int verify_path(char *path)
 223{
 224        char c;
 225
 226        goto inside;
 227        for (;;) {
 228                if (!c)
 229                        return 1;
 230                if (c == '/') {
 231inside:
 232                        c = *path++;
 233                        if (c != '/' && c != '.' && c != '\0')
 234                                continue;
 235                        return 0;
 236                }
 237                c = *path++;
 238        }
 239}
 240
 241static int remove_lock = 0;
 242
 243static void remove_lock_file(void)
 244{
 245        if (remove_lock)
 246                unlink(".git/index.lock");
 247}
 248
 249int main(int argc, char **argv)
 250{
 251        int i, newfd, entries;
 252        int allow_options = 1;
 253
 254        newfd = open(".git/index.lock", O_RDWR | O_CREAT | O_EXCL, 0600);
 255        if (newfd < 0)
 256                die("unable to create new cachefile");
 257
 258        atexit(remove_lock_file);
 259        remove_lock = 1;
 260
 261        entries = read_cache();
 262        if (entries < 0)
 263                die("cache corrupted");
 264
 265        for (i = 1 ; i < argc; i++) {
 266                char *path = argv[i];
 267
 268                if (allow_options && *path == '-') {
 269                        if (!strcmp(path, "--")) {
 270                                allow_options = 0;
 271                                continue;
 272                        }
 273                        if (!strcmp(path, "--add")) {
 274                                allow_add = 1;
 275                                continue;
 276                        }
 277                        if (!strcmp(path, "--remove")) {
 278                                allow_remove = 1;
 279                                continue;
 280                        }
 281                        if (!strcmp(path, "--refresh")) {
 282                                refresh_cache();
 283                                continue;
 284                        }
 285                        die("unknown option %s", path);
 286                }
 287                if (!verify_path(path)) {
 288                        fprintf(stderr, "Ignoring path %s\n", argv[i]);
 289                        continue;
 290                }
 291                if (add_file_to_cache(path))
 292                        die("Unable to add %s to database", path);
 293        }
 294        if (write_cache(newfd, active_cache, active_nr) ||
 295            rename(".git/index.lock", ".git/index"))
 296                die("Unable to write new cachefile");
 297
 298        remove_lock = 0;
 299        return 0;
 300}