quote.con commit Documentation: reworded the "Description" section of git-bisect.txt. (ee9cf14)
   1#include "cache.h"
   2#include "quote.h"
   3
   4int quote_path_fully = 1;
   5
   6/* Help to copy the thing properly quoted for the shell safety.
   7 * any single quote is replaced with '\'', any exclamation point
   8 * is replaced with '\!', and the whole thing is enclosed in a
   9 *
  10 * E.g.
  11 *  original     sq_quote     result
  12 *  name     ==> name      ==> 'name'
  13 *  a b      ==> a b       ==> 'a b'
  14 *  a'b      ==> a'\''b    ==> 'a'\''b'
  15 *  a!b      ==> a'\!'b    ==> 'a'\!'b'
  16 */
  17static inline int need_bs_quote(char c)
  18{
  19        return (c == '\'' || c == '!');
  20}
  21
  22void sq_quote_buf(struct strbuf *dst, const char *src)
  23{
  24        char *to_free = NULL;
  25
  26        if (dst->buf == src)
  27                to_free = strbuf_detach(dst, NULL);
  28
  29        strbuf_addch(dst, '\'');
  30        while (*src) {
  31                size_t len = strcspn(src, "'!");
  32                strbuf_add(dst, src, len);
  33                src += len;
  34                while (need_bs_quote(*src)) {
  35                        strbuf_addstr(dst, "'\\");
  36                        strbuf_addch(dst, *src++);
  37                        strbuf_addch(dst, '\'');
  38                }
  39        }
  40        strbuf_addch(dst, '\'');
  41        free(to_free);
  42}
  43
  44void sq_quote_print(FILE *stream, const char *src)
  45{
  46        char c;
  47
  48        fputc('\'', stream);
  49        while ((c = *src++)) {
  50                if (need_bs_quote(c)) {
  51                        fputs("'\\", stream);
  52                        fputc(c, stream);
  53                        fputc('\'', stream);
  54                } else {
  55                        fputc(c, stream);
  56                }
  57        }
  58        fputc('\'', stream);
  59}
  60
  61void sq_quote_argv(struct strbuf *dst, const char** argv, size_t maxlen)
  62{
  63        int i;
  64
  65        /* Copy into destination buffer. */
  66        strbuf_grow(dst, 255);
  67        for (i = 0; argv[i]; ++i) {
  68                strbuf_addch(dst, ' ');
  69                sq_quote_buf(dst, argv[i]);
  70                if (maxlen && dst->len > maxlen)
  71                        die("Too many or long arguments");
  72        }
  73}
  74
  75char *sq_dequote(char *arg)
  76{
  77        char *dst = arg;
  78        char *src = arg;
  79        char c;
  80
  81        if (*src != '\'')
  82                return NULL;
  83        for (;;) {
  84                c = *++src;
  85                if (!c)
  86                        return NULL;
  87                if (c != '\'') {
  88                        *dst++ = c;
  89                        continue;
  90                }
  91                /* We stepped out of sq */
  92                switch (*++src) {
  93                case '\0':
  94                        *dst = 0;
  95                        return arg;
  96                case '\\':
  97                        c = *++src;
  98                        if (need_bs_quote(c) && *++src == '\'') {
  99                                *dst++ = c;
 100                                continue;
 101                        }
 102                /* Fallthrough */
 103                default:
 104                        return NULL;
 105                }
 106        }
 107}
 108
 109/* 1 means: quote as octal
 110 * 0 means: quote as octal if (quote_path_fully)
 111 * -1 means: never quote
 112 * c: quote as "\\c"
 113 */
 114#define X8(x)   x, x, x, x, x, x, x, x
 115#define X16(x)  X8(x), X8(x)
 116static signed char const sq_lookup[256] = {
 117        /*           0    1    2    3    4    5    6    7 */
 118        /* 0x00 */   1,   1,   1,   1,   1,   1,   1, 'a',
 119        /* 0x08 */ 'b', 't', 'n', 'v', 'f', 'r',   1,   1,
 120        /* 0x10 */ X16(1),
 121        /* 0x20 */  -1,  -1, '"',  -1,  -1,  -1,  -1,  -1,
 122        /* 0x28 */ X16(-1), X16(-1), X16(-1),
 123        /* 0x58 */  -1,  -1,  -1,  -1,'\\',  -1,  -1,  -1,
 124        /* 0x60 */ X16(-1), X8(-1),
 125        /* 0x78 */  -1,  -1,  -1,  -1,  -1,  -1,  -1,   1,
 126        /* 0x80 */ /* set to 0 */
 127};
 128
 129static inline int sq_must_quote(char c)
 130{
 131        return sq_lookup[(unsigned char)c] + quote_path_fully > 0;
 132}
 133
 134/* returns the longest prefix not needing a quote up to maxlen if positive.
 135   This stops at the first \0 because it's marked as a character needing an
 136   escape */
 137static size_t next_quote_pos(const char *s, ssize_t maxlen)
 138{
 139        size_t len;
 140        if (maxlen < 0) {
 141                for (len = 0; !sq_must_quote(s[len]); len++);
 142        } else {
 143                for (len = 0; len < maxlen && !sq_must_quote(s[len]); len++);
 144        }
 145        return len;
 146}
 147
 148/*
 149 * C-style name quoting.
 150 *
 151 * (1) if sb and fp are both NULL, inspect the input name and counts the
 152 *     number of bytes that are needed to hold c_style quoted version of name,
 153 *     counting the double quotes around it but not terminating NUL, and
 154 *     returns it.
 155 *     However, if name does not need c_style quoting, it returns 0.
 156 *
 157 * (2) if sb or fp are not NULL, it emits the c_style quoted version
 158 *     of name, enclosed with double quotes if asked and needed only.
 159 *     Return value is the same as in (1).
 160 */
 161static size_t quote_c_style_counted(const char *name, ssize_t maxlen,
 162                                    struct strbuf *sb, FILE *fp, int no_dq)
 163{
 164#undef EMIT
 165#define EMIT(c)                                 \
 166        do {                                        \
 167                if (sb) strbuf_addch(sb, (c));          \
 168                if (fp) fputc((c), fp);                 \
 169                count++;                                \
 170        } while (0)
 171#define EMITBUF(s, l)                           \
 172        do {                                        \
 173                if (sb) strbuf_add(sb, (s), (l));       \
 174                if (fp) fwrite((s), (l), 1, fp);        \
 175                count += (l);                           \
 176        } while (0)
 177
 178        size_t len, count = 0;
 179        const char *p = name;
 180
 181        for (;;) {
 182                int ch;
 183
 184                len = next_quote_pos(p, maxlen);
 185                if (len == maxlen || !p[len])
 186                        break;
 187
 188                if (!no_dq && p == name)
 189                        EMIT('"');
 190
 191                EMITBUF(p, len);
 192                EMIT('\\');
 193                p += len;
 194                ch = (unsigned char)*p++;
 195                if (sq_lookup[ch] >= ' ') {
 196                        EMIT(sq_lookup[ch]);
 197                } else {
 198                        EMIT(((ch >> 6) & 03) + '0');
 199                        EMIT(((ch >> 3) & 07) + '0');
 200                        EMIT(((ch >> 0) & 07) + '0');
 201                }
 202        }
 203
 204        EMITBUF(p, len);
 205        if (p == name)   /* no ending quote needed */
 206                return 0;
 207
 208        if (!no_dq)
 209                EMIT('"');
 210        return count;
 211}
 212
 213size_t quote_c_style(const char *name, struct strbuf *sb, FILE *fp, int nodq)
 214{
 215        return quote_c_style_counted(name, -1, sb, fp, nodq);
 216}
 217
 218void quote_two_c_style(struct strbuf *sb, const char *prefix, const char *path, int nodq)
 219{
 220        if (quote_c_style(prefix, NULL, NULL, 0) ||
 221            quote_c_style(path, NULL, NULL, 0)) {
 222                if (!nodq)
 223                        strbuf_addch(sb, '"');
 224                quote_c_style(prefix, sb, NULL, 1);
 225                quote_c_style(path, sb, NULL, 1);
 226                if (!nodq)
 227                        strbuf_addch(sb, '"');
 228        } else {
 229                strbuf_addstr(sb, prefix);
 230                strbuf_addstr(sb, path);
 231        }
 232}
 233
 234void write_name_quoted(const char *name, FILE *fp, int terminator)
 235{
 236        if (terminator) {
 237                quote_c_style(name, NULL, fp, 0);
 238        } else {
 239                fputs(name, fp);
 240        }
 241        fputc(terminator, fp);
 242}
 243
 244extern void write_name_quotedpfx(const char *pfx, size_t pfxlen,
 245                                 const char *name, FILE *fp, int terminator)
 246{
 247        int needquote = 0;
 248
 249        if (terminator) {
 250                needquote = next_quote_pos(pfx, pfxlen) < pfxlen
 251                        || name[next_quote_pos(name, -1)];
 252        }
 253        if (needquote) {
 254                fputc('"', fp);
 255                quote_c_style_counted(pfx, pfxlen, NULL, fp, 1);
 256                quote_c_style(name, NULL, fp, 1);
 257                fputc('"', fp);
 258        } else {
 259                fwrite(pfx, pfxlen, 1, fp);
 260                fputs(name, fp);
 261        }
 262        fputc(terminator, fp);
 263}
 264
 265/* quote path as relative to the given prefix */
 266char *quote_path_relative(const char *in, int len,
 267                          struct strbuf *out, const char *prefix)
 268{
 269        int needquote;
 270
 271        if (len < 0)
 272                len = strlen(in);
 273
 274        /* "../" prefix itself does not need quoting, but "in" might. */
 275        needquote = next_quote_pos(in, len) < len;
 276        strbuf_setlen(out, 0);
 277        strbuf_grow(out, len);
 278
 279        if (needquote)
 280                strbuf_addch(out, '"');
 281        if (prefix) {
 282                int off = 0;
 283                while (prefix[off] && off < len && prefix[off] == in[off])
 284                        if (prefix[off] == '/') {
 285                                prefix += off + 1;
 286                                in += off + 1;
 287                                len -= off + 1;
 288                                off = 0;
 289                        } else
 290                                off++;
 291
 292                for (; *prefix; prefix++)
 293                        if (*prefix == '/')
 294                                strbuf_addstr(out, "../");
 295        }
 296
 297        quote_c_style_counted (in, len, out, NULL, 1);
 298
 299        if (needquote)
 300                strbuf_addch(out, '"');
 301        if (!out->len)
 302                strbuf_addstr(out, "./");
 303
 304        return out->buf;
 305}
 306
 307/*
 308 * C-style name unquoting.
 309 *
 310 * Quoted should point at the opening double quote.
 311 * + Returns 0 if it was able to unquote the string properly, and appends the
 312 *   result in the strbuf `sb'.
 313 * + Returns -1 in case of error, and doesn't touch the strbuf. Though note
 314 *   that this function will allocate memory in the strbuf, so calling
 315 *   strbuf_release is mandatory whichever result unquote_c_style returns.
 316 *
 317 * Updates endp pointer to point at one past the ending double quote if given.
 318 */
 319int unquote_c_style(struct strbuf *sb, const char *quoted, const char **endp)
 320{
 321        size_t oldlen = sb->len, len;
 322        int ch, ac;
 323
 324        if (*quoted++ != '"')
 325                return -1;
 326
 327        for (;;) {
 328                len = strcspn(quoted, "\"\\");
 329                strbuf_add(sb, quoted, len);
 330                quoted += len;
 331
 332                switch (*quoted++) {
 333                  case '"':
 334                        if (endp)
 335                                *endp = quoted;
 336                        return 0;
 337                  case '\\':
 338                        break;
 339                  default:
 340                        goto error;
 341                }
 342
 343                switch ((ch = *quoted++)) {
 344                case 'a': ch = '\a'; break;
 345                case 'b': ch = '\b'; break;
 346                case 'f': ch = '\f'; break;
 347                case 'n': ch = '\n'; break;
 348                case 'r': ch = '\r'; break;
 349                case 't': ch = '\t'; break;
 350                case 'v': ch = '\v'; break;
 351
 352                case '\\': case '"':
 353                        break; /* verbatim */
 354
 355                /* octal values with first digit over 4 overflow */
 356                case '0': case '1': case '2': case '3':
 357                                        ac = ((ch - '0') << 6);
 358                        if ((ch = *quoted++) < '0' || '7' < ch)
 359                                goto error;
 360                                        ac |= ((ch - '0') << 3);
 361                        if ((ch = *quoted++) < '0' || '7' < ch)
 362                                goto error;
 363                                        ac |= (ch - '0');
 364                                        ch = ac;
 365                                        break;
 366                                default:
 367                        goto error;
 368                        }
 369                strbuf_addch(sb, ch);
 370                }
 371
 372  error:
 373        strbuf_setlen(sb, oldlen);
 374        return -1;
 375}
 376
 377/* quoting as a string literal for other languages */
 378
 379void perl_quote_print(FILE *stream, const char *src)
 380{
 381        const char sq = '\'';
 382        const char bq = '\\';
 383        char c;
 384
 385        fputc(sq, stream);
 386        while ((c = *src++)) {
 387                if (c == sq || c == bq)
 388                        fputc(bq, stream);
 389                fputc(c, stream);
 390        }
 391        fputc(sq, stream);
 392}
 393
 394void python_quote_print(FILE *stream, const char *src)
 395{
 396        const char sq = '\'';
 397        const char bq = '\\';
 398        const char nl = '\n';
 399        char c;
 400
 401        fputc(sq, stream);
 402        while ((c = *src++)) {
 403                if (c == nl) {
 404                        fputc(bq, stream);
 405                        fputc('n', stream);
 406                        continue;
 407                }
 408                if (c == sq || c == bq)
 409                        fputc(bq, stream);
 410                fputc(c, stream);
 411        }
 412        fputc(sq, stream);
 413}
 414
 415void tcl_quote_print(FILE *stream, const char *src)
 416{
 417        char c;
 418
 419        fputc('"', stream);
 420        while ((c = *src++)) {
 421                switch (c) {
 422                case '[': case ']':
 423                case '{': case '}':
 424                case '$': case '\\': case '"':
 425                        fputc('\\', stream);
 426                default:
 427                        fputc(c, stream);
 428                        break;
 429                case '\f':
 430                        fputs("\\f", stream);
 431                        break;
 432                case '\r':
 433                        fputs("\\r", stream);
 434                        break;
 435                case '\n':
 436                        fputs("\\n", stream);
 437                        break;
 438                case '\t':
 439                        fputs("\\t", stream);
 440                        break;
 441                case '\v':
 442                        fputs("\\v", stream);
 443                        break;
 444                }
 445        }
 446        fputc('"', stream);
 447}