Andrew's git - gitweb.git/blob

5fdaee75714fa6a42601fbb366aeafb18f3334fb
   1#include "cache.h"
   2#include "attr.h"
   3#include "run-command.h"
   4
   5/*
   6 * convert.c - convert a file when checking it out and checking it in.
   7 *
   8 * This should use the pathname to decide on whether it wants to do some
   9 * more interesting conversions (automatic gzip/unzip, general format
  10 * conversions etc etc), but by default it just does automatic CRLF<->LF
  11 * translation when the "auto_crlf" option is set.
  12 */
  13
  14#define CRLF_GUESS      (-1)
  15#define CRLF_BINARY     0
  16#define CRLF_TEXT       1
  17#define CRLF_INPUT      2
  18
  19struct text_stat {
  20        /* CR, LF and CRLF counts */
  21        unsigned cr, lf, crlf;
  22
  23        /* These are just approximations! */
  24        unsigned printable, nonprintable;
  25};
  26
  27static void gather_stats(const char *buf, unsigned long size, struct text_stat *stats)
  28{
  29        unsigned long i;
  30
  31        memset(stats, 0, sizeof(*stats));
  32
  33        for (i = 0; i < size; i++) {
  34                unsigned char c = buf[i];
  35                if (c == '\r') {
  36                        stats->cr++;
  37                        if (i+1 < size && buf[i+1] == '\n')
  38                                stats->crlf++;
  39                        continue;
  40                }
  41                if (c == '\n') {
  42                        stats->lf++;
  43                        continue;
  44                }
  45                if (c == 127)
  46                        /* DEL */
  47                        stats->nonprintable++;
  48                else if (c < 32) {
  49                        switch (c) {
  50                                /* BS, HT, ESC and FF */
  51                        case '\b': case '\t': case '\033': case '\014':
  52                                stats->printable++;
  53                                break;
  54                        default:
  55                                stats->nonprintable++;
  56                        }
  57                }
  58                else
  59                        stats->printable++;
  60        }
  61}
  62
  63/*
  64 * The same heuristics as diff.c::mmfile_is_binary()
  65 */
  66static int is_binary(unsigned long size, struct text_stat *stats)
  67{
  68
  69        if ((stats->printable >> 7) < stats->nonprintable)
  70                return 1;
  71        /*
  72         * Other heuristics? Average line length might be relevant,
  73         * as might LF vs CR vs CRLF counts..
  74         *
  75         * NOTE! It might be normal to have a low ratio of CRLF to LF
  76         * (somebody starts with a LF-only file and edits it with an editor
  77         * that adds CRLF only to lines that are added..). But do  we
  78         * want to support CR-only? Probably not.
  79         */
  80        return 0;
  81}
  82
  83static char *crlf_to_git(const char *path, const char *src, unsigned long *sizep, int action)
  84{
  85        char *buffer, *dst;
  86        unsigned long size, nsize;
  87        struct text_stat stats;
  88
  89        if ((action == CRLF_BINARY) || (action == CRLF_GUESS && !auto_crlf))
  90                return NULL;
  91
  92        size = *sizep;
  93        if (!size)
  94                return NULL;
  95
  96        gather_stats(src, size, &stats);
  97
  98        /* No CR? Nothing to convert, regardless. */
  99        if (!stats.cr)
 100                return NULL;
 101
 102        if (action == CRLF_GUESS) {
 103                /*
 104                 * We're currently not going to even try to convert stuff
 105                 * that has bare CR characters. Does anybody do that crazy
 106                 * stuff?
 107                 */
 108                if (stats.cr != stats.crlf)
 109                        return NULL;
 110
 111                /*
 112                 * And add some heuristics for binary vs text, of course...
 113                 */
 114                if (is_binary(size, &stats))
 115                        return NULL;
 116        }
 117
 118        /*
 119         * Ok, allocate a new buffer, fill it in, and return it
 120         * to let the caller know that we switched buffers.
 121         */
 122        nsize = size - stats.crlf;
 123        buffer = xmalloc(nsize);
 124        *sizep = nsize;
 125
 126        dst = buffer;
 127        if (action == CRLF_GUESS) {
 128                /*
 129                 * If we guessed, we already know we rejected a file with
 130                 * lone CR, and we can strip a CR without looking at what
 131                 * follow it.
 132                 */
 133                do {
 134                        unsigned char c = *src++;
 135                        if (c != '\r')
 136                                *dst++ = c;
 137                } while (--size);
 138        } else {
 139                do {
 140                        unsigned char c = *src++;
 141                        if (! (c == '\r' && (1 < size && *src == '\n')))
 142                                *dst++ = c;
 143                } while (--size);
 144        }
 145
 146        return buffer;
 147}
 148
 149static char *crlf_to_worktree(const char *path, const char *src, unsigned long *sizep, int action)
 150{
 151        char *buffer, *dst;
 152        unsigned long size, nsize;
 153        struct text_stat stats;
 154        unsigned char last;
 155
 156        if ((action == CRLF_BINARY) || (action == CRLF_INPUT) ||
 157            (action == CRLF_GUESS && auto_crlf <= 0))
 158                return NULL;
 159
 160        size = *sizep;
 161        if (!size)
 162                return NULL;
 163
 164        gather_stats(src, size, &stats);
 165
 166        /* No LF? Nothing to convert, regardless. */
 167        if (!stats.lf)
 168                return NULL;
 169
 170        /* Was it already in CRLF format? */
 171        if (stats.lf == stats.crlf)
 172                return NULL;
 173
 174        if (action == CRLF_GUESS) {
 175                /* If we have any bare CR characters, we're not going to touch it */
 176                if (stats.cr != stats.crlf)
 177                        return NULL;
 178
 179                if (is_binary(size, &stats))
 180                        return NULL;
 181        }
 182
 183        /*
 184         * Ok, allocate a new buffer, fill it in, and return it
 185         * to let the caller know that we switched buffers.
 186         */
 187        nsize = size + stats.lf - stats.crlf;
 188        buffer = xmalloc(nsize);
 189        *sizep = nsize;
 190        last = 0;
 191
 192        dst = buffer;
 193        do {
 194                unsigned char c = *src++;
 195                if (c == '\n' && last != '\r')
 196                        *dst++ = '\r';
 197                *dst++ = c;
 198                last = c;
 199        } while (--size);
 200
 201        return buffer;
 202}
 203
 204static void setup_convert_check(struct git_attr_check *check)
 205{
 206        static struct git_attr *attr_crlf;
 207        static struct git_attr *attr_ident;
 208
 209        if (!attr_crlf) {
 210                attr_crlf = git_attr("crlf", 4);
 211                attr_ident = git_attr("ident", 5);
 212        }
 213        check[0].attr = attr_crlf;
 214        check[1].attr = attr_ident;
 215}
 216
 217static int count_ident(const char *cp, unsigned long size)
 218{
 219        /*
 220         * "$ident: 0000000000000000000000000000000000000000 $" <=> "$ident$"
 221         */
 222        int cnt = 0;
 223        char ch;
 224
 225        while (size) {
 226                ch = *cp++;
 227                size--;
 228                if (ch != '$')
 229                        continue;
 230                if (size < 6)
 231                        break;
 232                if (memcmp("ident", cp, 5))
 233                        continue;
 234                ch = cp[5];
 235                cp += 6;
 236                size -= 6;
 237                if (ch == '$')
 238                        cnt++; /* $ident$ */
 239                if (ch != ':')
 240                        continue;
 241
 242                /*
 243                 * "$ident: ... "; scan up to the closing dollar sign and discard.
 244                 */
 245                while (size) {
 246                        ch = *cp++;
 247                        size--;
 248                        if (ch == '$') {
 249                                cnt++;
 250                                break;
 251                        }
 252                }
 253        }
 254        return cnt;
 255}
 256
 257static char *ident_to_git(const char *path, const char *src, unsigned long *sizep, int ident)
 258{
 259        int cnt;
 260        unsigned long size;
 261        char *dst, *buf;
 262
 263        if (!ident)
 264                return NULL;
 265        size = *sizep;
 266        cnt = count_ident(src, size);
 267        if (!cnt)
 268                return NULL;
 269        buf = xmalloc(size);
 270
 271        for (dst = buf; size; size--) {
 272                char ch = *src++;
 273                *dst++ = ch;
 274                if ((ch == '$') && (6 <= size) &&
 275                    !memcmp("ident:", src, 6)) {
 276                        unsigned long rem = size - 6;
 277                        const char *cp = src + 6;
 278                        do {
 279                                ch = *cp++;
 280                                if (ch == '$')
 281                                        break;
 282                                rem--;
 283                        } while (rem);
 284                        if (!rem)
 285                                continue;
 286                        memcpy(dst, "ident$", 6);
 287                        dst += 6;
 288                        size -= (cp - src);
 289                        src = cp;
 290                }
 291        }
 292
 293        *sizep = dst - buf;
 294        return buf;
 295}
 296
 297static char *ident_to_worktree(const char *path, const char *src, unsigned long *sizep, int ident)
 298{
 299        int cnt;
 300        unsigned long size;
 301        char *dst, *buf;
 302        unsigned char sha1[20];
 303
 304        if (!ident)
 305                return NULL;
 306
 307        size = *sizep;
 308        cnt = count_ident(src, size);
 309        if (!cnt)
 310                return NULL;
 311
 312        hash_sha1_file(src, size, "blob", sha1);
 313        buf = xmalloc(size + cnt * 43);
 314
 315        for (dst = buf; size; size--) {
 316                const char *cp;
 317                char ch = *src++;
 318                *dst++ = ch;
 319                if ((ch != '$') || (size < 6) || memcmp("ident", src, 5))
 320                        continue;
 321
 322                if (src[5] == ':') {
 323                        /* discard up to but not including the closing $ */
 324                        unsigned long rem = size - 6;
 325                        cp = src + 6;
 326                        do {
 327                                ch = *cp++;
 328                                if (ch == '$')
 329                                        break;
 330                                rem--;
 331                        } while (rem);
 332                        if (!rem)
 333                                continue;
 334                        size -= (cp - src);
 335                } else if (src[5] == '$')
 336                        cp = src + 5;
 337                else
 338                        continue;
 339
 340                memcpy(dst, "ident: ", 7);
 341                dst += 7;
 342                memcpy(dst, sha1_to_hex(sha1), 40);
 343                dst += 40;
 344                *dst++ = ' ';
 345                size -= (cp - src);
 346                src = cp;
 347                *dst++ = *src++;
 348                size--;
 349        }
 350
 351        *sizep = dst - buf;
 352        return buf;
 353}
 354
 355static int git_path_check_crlf(const char *path, struct git_attr_check *check)
 356{
 357        const char *value = check->value;
 358
 359        if (ATTR_TRUE(value))
 360                return CRLF_TEXT;
 361        else if (ATTR_FALSE(value))
 362                return CRLF_BINARY;
 363        else if (ATTR_UNSET(value))
 364                ;
 365        else if (!strcmp(value, "input"))
 366                return CRLF_INPUT;
 367        return CRLF_GUESS;
 368}
 369
 370static int git_path_check_ident(const char *path, struct git_attr_check *check)
 371{
 372        const char *value = check->value;
 373
 374        return !!ATTR_TRUE(value);
 375}
 376
 377char *convert_to_git(const char *path, const char *src, unsigned long *sizep)
 378{
 379        struct git_attr_check check[2];
 380        int crlf = CRLF_GUESS;
 381        int ident = 0;
 382        char *buf, *buf2;
 383
 384        setup_convert_check(check);
 385        if (!git_checkattr(path, ARRAY_SIZE(check), check)) {
 386                crlf = git_path_check_crlf(path, check + 0);
 387                ident = git_path_check_ident(path, check + 1);
 388        }
 389
 390        buf = crlf_to_git(path, src, sizep, crlf);
 391
 392        buf2 = ident_to_git(path, buf ? buf : src, sizep, ident);
 393        if (buf2) {
 394                free(buf);
 395                buf = buf2;
 396        }
 397
 398        return buf;
 399}
 400
 401char *convert_to_working_tree(const char *path, const char *src, unsigned long *sizep)
 402{
 403        struct git_attr_check check[2];
 404        int crlf = CRLF_GUESS;
 405        int ident = 0;
 406        char *buf, *buf2;
 407
 408        setup_convert_check(check);
 409        if (!git_checkattr(path, ARRAY_SIZE(check), check)) {
 410                crlf = git_path_check_crlf(path, check + 0);
 411                ident = git_path_check_ident(path, check + 1);
 412        }
 413
 414        buf = ident_to_worktree(path, src, sizep, ident);
 415
 416        buf2 = crlf_to_worktree(path, buf ? buf : src, sizep, crlf);
 417        if (buf2) {
 418                free(buf);
 419                buf = buf2;
 420        }
 421
 422        return buf;
 423}