convert-objects.c

   1 #define _XOPEN_SOURCE /* glibc2 needs this */
   2 #include <time.h>
   3 #include "cache.h"
   4
   5 struct entry {
   6         unsigned char old_sha1[20];
   7         unsigned char new_sha1[20];
   8         int converted;
   9 };
  10
  11 #define MAXOBJECTS (1000000)
  12
  13 static struct entry *convert[MAXOBJECTS];
  14 static int nr_convert;
  15
  16 static struct entry * convert_entry(unsigned char *sha1);
  17
  18 static struct entry *insert_new(unsigned char *sha1, int pos)
  19 {
  20         struct entry *new = xmalloc(sizeof(struct entry));
  21         memset(new, 0, sizeof(*new));
  22         memcpy(new->old_sha1, sha1, 20);
  23         memmove(convert + pos + 1, convert + pos, (nr_convert - pos) * sizeof(struct entry *));
  24         convert[pos] = new;
  25         nr_convert++;
  26         if (nr_convert == MAXOBJECTS)
  27                 die("you're kidding me - hit maximum object limit");
  28         return new;
  29 }
  30
  31 static struct entry *lookup_entry(unsigned char *sha1)
  32 {
  33         int low = 0, high = nr_convert;
  34
  35         while (low < high) {
  36                 int next = (low + high) / 2;
  37                 struct entry *n = convert[next];
  38                 int cmp = memcmp(sha1, n->old_sha1, 20);
  39                 if (!cmp)
  40                         return n;
  41                 if (cmp < 0) {
  42                         high = next;
  43                         continue;
  44                 }
  45                 low = next+1;
  46         }
  47         return insert_new(sha1, low);
  48 }
  49
  50 static void convert_binary_sha1(void *buffer)
  51 {
  52         struct entry *entry = convert_entry(buffer);
  53         memcpy(buffer, entry->new_sha1, 20);
  54 }
  55
  56 static void convert_ascii_sha1(void *buffer)
  57 {
  58         unsigned char sha1[20];
  59         struct entry *entry;
  60
  61         if (get_sha1_hex(buffer, sha1))
  62                 die("expected sha1, got '%s'", (char*) buffer);
  63         entry = convert_entry(sha1);
  64         memcpy(buffer, sha1_to_hex(entry->new_sha1), 40);
  65 }
  66
  67 static unsigned int convert_mode(unsigned int mode)
  68 {
  69         unsigned int newmode;
  70
  71         newmode = mode & S_IFMT;
  72         if (S_ISREG(mode))
  73                 newmode |= (mode & 0100) ? 0755 : 0644;
  74         return newmode;
  75 }
  76
  77 static int write_subdirectory(void *buffer, unsigned long size, const char *base, int baselen, unsigned char *result_sha1)
  78 {
  79         char *new = xmalloc(size);
  80         unsigned long newlen = 0;
  81         unsigned long used;
  82
  83         used = 0;
  84         while (size) {
  85                 int len = 21 + strlen(buffer);
  86                 char *path = strchr(buffer, ' ');
  87                 unsigned char *sha1;
  88                 unsigned int mode;
  89                 char *slash, *origpath;
  90
  91                 if (!path || sscanf(buffer, "%o", &mode) != 1)
  92                         die("bad tree conversion");
  93                 mode = convert_mode(mode);
  94                 path++;
  95                 if (memcmp(path, base, baselen))
  96                         break;
  97                 origpath = path;
  98                 path += baselen;
  99                 slash = strchr(path, '/');
 100                 if (!slash) {
 101                         newlen += sprintf(new + newlen, "%o %s", mode, path);
 102                         new[newlen++] = '\0';
 103                         memcpy(new + newlen, buffer + len - 20, 20);
 104                         newlen += 20;
 105
 106                         used += len;
 107                         size -= len;
 108                         buffer += len;
 109                         continue;
 110                 }
 111
 112                 newlen += sprintf(new + newlen, "%o %.*s", S_IFDIR, (int)(slash - path), path);
 113                 new[newlen++] = 0;
 114                 sha1 = (unsigned char *)(new + newlen);
 115                 newlen += 20;
 116
 117                 len = write_subdirectory(buffer, size, origpath, slash-origpath+1, sha1);
 118
 119                 used += len;
 120                 size -= len;
 121                 buffer += len;
 122         }
 123
 124         write_sha1_file(new, newlen, "tree", result_sha1);
 125         free(new);
 126         return used;
 127 }
 128
 129 static void convert_tree(void *buffer, unsigned long size, unsigned char *result_sha1)
 130 {
 131         void *orig_buffer = buffer;
 132         unsigned long orig_size = size;
 133
 134         while (size) {
 135                 int len = 1+strlen(buffer);
 136
 137                 convert_binary_sha1(buffer + len);
 138
 139                 len += 20;
 140                 if (len > size)
 141                         die("corrupt tree object");
 142                 size -= len;
 143                 buffer += len;
 144         }
 145
 146         write_subdirectory(orig_buffer, orig_size, "", 0, result_sha1);
 147 }
 148
 149 static unsigned long parse_oldstyle_date(const char *buf)
 150 {
 151         char c, *p;
 152         char buffer[100];
 153         struct tm tm;
 154         const char *formats[] = {
 155                 "%c",
 156                 "%a %b %d %T",
 157                 "%Z",
 158                 "%Y",
 159                 " %Y",
 160                 NULL
 161         };
 162         /* We only ever did two timezones in the bad old format .. */
 163         const char *timezones[] = {
 164                 "PDT", "PST", "CEST", NULL
 165         };
 166         const char **fmt = formats;
 167
 168         p = buffer;
 169         while (isspace(c = *buf))
 170                 buf++;
 171         while ((c = *buf++) != '\n')
 172                 *p++ = c;
 173         *p++ = 0;
 174         buf = buffer;
 175         memset(&tm, 0, sizeof(tm));
 176         do {
 177                 const char *next = strptime(buf, *fmt, &tm);
 178                 if (next) {
 179                         if (!*next)
 180                                 return mktime(&tm);
 181                         buf = next;
 182                 } else {
 183                         const char **p = timezones;
 184                         while (isspace(*buf))
 185                                 buf++;
 186                         while (*p) {
 187                                 if (!memcmp(buf, *p, strlen(*p))) {
 188                                         buf += strlen(*p);
 189                                         break;
 190                                 }
 191                                 p++;
 192                         }
 193                 }
 194                 fmt++;
 195         } while (*buf && *fmt);
 196         printf("left: %s\n", buf);
 197         return mktime(&tm);
 198 }
 199
 200 static int convert_date_line(char *dst, void **buf, unsigned long *sp)
 201 {
 202         unsigned long size = *sp;
 203         char *line = *buf;
 204         char *next = strchr(line, '\n');
 205         char *date = strchr(line, '>');
 206         int len;
 207
 208         if (!next || !date)
 209                 die("missing or bad author/committer line %s", line);
 210         next++; date += 2;
 211
 212         *buf = next;
 213         *sp = size - (next - line);
 214
 215         len = date - line;
 216         memcpy(dst, line, len);
 217         dst += len;
 218
 219         /* Is it already in new format? */
 220         if (isdigit(*date)) {
 221                 int datelen = next - date;
 222                 memcpy(dst, date, datelen);
 223                 return len + datelen;
 224         }
 225
 226         /*
 227          * Hacky hacky: one of the sparse old-style commits does not have
 228          * any date at all, but we can fake it by using the committer date.
 229          */
 230         if (*date == '\n' && strchr(next, '>'))
 231                 date = strchr(next, '>')+2;
 232
 233         return len + sprintf(dst, "%lu -0700\n", parse_oldstyle_date(date));
 234 }
 235
 236 static void convert_date(void *buffer, unsigned long size, unsigned char *result_sha1)
 237 {
 238         char *new = xmalloc(size + 100);
 239         unsigned long newlen = 0;
 240
 241         // "tree <sha1>\n"
 242         memcpy(new + newlen, buffer, 46);
 243         newlen += 46;
 244         buffer += 46;
 245         size -= 46;
 246
 247         // "parent <sha1>\n"
 248         while (!memcmp(buffer, "parent ", 7)) {
 249                 memcpy(new + newlen, buffer, 48);
 250                 newlen += 48;
 251                 buffer += 48;
 252                 size -= 48;
 253         }
 254
 255         // "author xyz <xyz> date"
 256         newlen += convert_date_line(new + newlen, &buffer, &size);
 257         // "committer xyz <xyz> date"
 258         newlen += convert_date_line(new + newlen, &buffer, &size);
 259
 260         // Rest
 261         memcpy(new + newlen, buffer, size);
 262         newlen += size;
 263
 264         write_sha1_file(new, newlen, "commit", result_sha1);
 265         free(new);
 266 }
 267
 268 static void convert_commit(void *buffer, unsigned long size, unsigned char *result_sha1)
 269 {
 270         void *orig_buffer = buffer;
 271         unsigned long orig_size = size;
 272
 273         if (memcmp(buffer, "tree ", 5))
 274                 die("Bad commit '%s'", (char*) buffer);
 275         convert_ascii_sha1(buffer+5);
 276         buffer += 46;    /* "tree " + "hex sha1" + "\n" */
 277         while (!memcmp(buffer, "parent ", 7)) {
 278                 convert_ascii_sha1(buffer+7);
 279                 buffer += 48;
 280         }
 281         convert_date(orig_buffer, orig_size, result_sha1);
 282 }
 283
 284 static struct entry * convert_entry(unsigned char *sha1)
 285 {
 286         struct entry *entry = lookup_entry(sha1);
 287         char type[20];
 288         void *buffer, *data;
 289         unsigned long size;
 290
 291         if (entry->converted)
 292                 return entry;
 293         data = read_sha1_file(sha1, type, &size);
 294         if (!data)
 295                 die("unable to read object %s", sha1_to_hex(sha1));
 296
 297         buffer = xmalloc(size);
 298         memcpy(buffer, data, size);
 299
 300         if (!strcmp(type, "blob")) {
 301                 write_sha1_file(buffer, size, "blob", entry->new_sha1);
 302         } else if (!strcmp(type, "tree"))
 303                 convert_tree(buffer, size, entry->new_sha1);
 304         else if (!strcmp(type, "commit"))
 305                 convert_commit(buffer, size, entry->new_sha1);
 306         else
 307                 die("unknown object type '%s' in %s", type, sha1_to_hex(sha1));
 308         entry->converted = 1;
 309         free(buffer);
 310         free(data);
 311         return entry;
 312 }
 313
 314 int main(int argc, char **argv)
 315 {
 316         unsigned char sha1[20];
 317         struct entry *entry;
 318
 319         setup_git_directory();
 320
 321         if (argc != 2 || get_sha1(argv[1], sha1))
 322                 usage("git-convert-objects <sha1>");
 323
 324         entry = convert_entry(sha1);
 325         printf("new sha1: %s\n", sha1_to_hex(entry->new_sha1));
 326         return 0;
 327 }