convert-cache.c

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