xdiff-interface.c

   1 #include "cache.h"
   2 #include "config.h"
   3 #include "object-store.h"
   4 #include "xdiff-interface.h"
   5 #include "xdiff/xtypes.h"
   6 #include "xdiff/xdiffi.h"
   7 #include "xdiff/xemit.h"
   8 #include "xdiff/xmacros.h"
   9 #include "xdiff/xutils.h"
  10
  11 struct xdiff_emit_state {
  12         xdiff_emit_hunk_fn hunk_fn;
  13         xdiff_emit_line_fn line_fn;
  14         void *consume_callback_data;
  15         struct strbuf remainder;
  16 };
  17
  18 static int parse_num(char **cp_p, int *num_p)
  19 {
  20         char *cp = *cp_p;
  21         int num = 0;
  22
  23         while ('0' <= *cp && *cp <= '9')
  24                 num = num * 10 + *cp++ - '0';
  25         if (!(cp - *cp_p))
  26                 return -1;
  27         *cp_p = cp;
  28         *num_p = num;
  29         return 0;
  30 }
  31
  32 int parse_hunk_header(char *line, int len,
  33                       int *ob, int *on,
  34                       int *nb, int *nn)
  35 {
  36         char *cp;
  37         cp = line + 4;
  38         if (parse_num(&cp, ob)) {
  39         bad_line:
  40                 return error("malformed diff output: %s", line);
  41         }
  42         if (*cp == ',') {
  43                 cp++;
  44                 if (parse_num(&cp, on))
  45                         goto bad_line;
  46         }
  47         else
  48                 *on = 1;
  49         if (*cp++ != ' ' || *cp++ != '+')
  50                 goto bad_line;
  51         if (parse_num(&cp, nb))
  52                 goto bad_line;
  53         if (*cp == ',') {
  54                 cp++;
  55                 if (parse_num(&cp, nn))
  56                         goto bad_line;
  57         }
  58         else
  59                 *nn = 1;
  60         return -!!memcmp(cp, " @@", 3);
  61 }
  62
  63 static int xdiff_out_hunk(void *priv_,
  64                           long old_begin, long old_nr,
  65                           long new_begin, long new_nr,
  66                           const char *func, long funclen)
  67 {
  68         struct xdiff_emit_state *priv = priv_;
  69
  70         if (priv->remainder.len)
  71                 BUG("xdiff emitted hunk in the middle of a line");
  72
  73         priv->hunk_fn(priv->consume_callback_data,
  74                       old_begin, old_nr, new_begin, new_nr,
  75                       func, funclen);
  76         return 0;
  77 }
  78
  79 static void consume_one(void *priv_, char *s, unsigned long size)
  80 {
  81         struct xdiff_emit_state *priv = priv_;
  82         char *ep;
  83         while (size) {
  84                 unsigned long this_size;
  85                 ep = memchr(s, '\n', size);
  86                 this_size = (ep == NULL) ? size : (ep - s + 1);
  87                 priv->line_fn(priv->consume_callback_data, s, this_size);
  88                 size -= this_size;
  89                 s += this_size;
  90         }
  91 }
  92
  93 static int xdiff_outf(void *priv_, mmbuffer_t *mb, int nbuf)
  94 {
  95         struct xdiff_emit_state *priv = priv_;
  96         int i;
  97
  98         if (!priv->line_fn)
  99                 return 0;
 100
 101         for (i = 0; i < nbuf; i++) {
 102                 if (mb[i].ptr[mb[i].size-1] != '\n') {
 103                         /* Incomplete line */
 104                         strbuf_add(&priv->remainder, mb[i].ptr, mb[i].size);
 105                         continue;
 106                 }
 107
 108                 /* we have a complete line */
 109                 if (!priv->remainder.len) {
 110                         consume_one(priv, mb[i].ptr, mb[i].size);
 111                         continue;
 112                 }
 113                 strbuf_add(&priv->remainder, mb[i].ptr, mb[i].size);
 114                 consume_one(priv, priv->remainder.buf, priv->remainder.len);
 115                 strbuf_reset(&priv->remainder);
 116         }
 117         if (priv->remainder.len) {
 118                 consume_one(priv, priv->remainder.buf, priv->remainder.len);
 119                 strbuf_reset(&priv->remainder);
 120         }
 121         return 0;
 122 }
 123
 124 /*
 125  * Trim down common substring at the end of the buffers,
 126  * but end on a complete line.
 127  */
 128 static void trim_common_tail(mmfile_t *a, mmfile_t *b)
 129 {
 130         const int blk = 1024;
 131         long trimmed = 0, recovered = 0;
 132         char *ap = a->ptr + a->size;
 133         char *bp = b->ptr + b->size;
 134         long smaller = (a->size < b->size) ? a->size : b->size;
 135
 136         while (blk + trimmed <= smaller && !memcmp(ap - blk, bp - blk, blk)) {
 137                 trimmed += blk;
 138                 ap -= blk;
 139                 bp -= blk;
 140         }
 141
 142         while (recovered < trimmed)
 143                 if (ap[recovered++] == '\n')
 144                         break;
 145         a->size -= trimmed - recovered;
 146         b->size -= trimmed - recovered;
 147 }
 148
 149 int xdi_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp, xdemitconf_t const *xecfg, xdemitcb_t *xecb)
 150 {
 151         mmfile_t a = *mf1;
 152         mmfile_t b = *mf2;
 153
 154         if (mf1->size > MAX_XDIFF_SIZE || mf2->size > MAX_XDIFF_SIZE)
 155                 return -1;
 156
 157         if (!xecfg->ctxlen && !(xecfg->flags & XDL_EMIT_FUNCCONTEXT))
 158                 trim_common_tail(&a, &b);
 159
 160         return xdl_diff(&a, &b, xpp, xecfg, xecb);
 161 }
 162
 163 void discard_hunk_line(void *priv,
 164                        long ob, long on, long nb, long nn,
 165                        const char *func, long funclen)
 166 {
 167 }
 168
 169 int xdi_diff_outf(mmfile_t *mf1, mmfile_t *mf2,
 170                   xdiff_emit_hunk_fn hunk_fn,
 171                   xdiff_emit_line_fn line_fn,
 172                   void *consume_callback_data,
 173                   xpparam_t const *xpp, xdemitconf_t const *xecfg)
 174 {
 175         int ret;
 176         struct xdiff_emit_state state;
 177         xdemitcb_t ecb;
 178
 179         memset(&state, 0, sizeof(state));
 180         state.hunk_fn = hunk_fn;
 181         state.line_fn = line_fn;
 182         state.consume_callback_data = consume_callback_data;
 183         memset(&ecb, 0, sizeof(ecb));
 184         if (hunk_fn)
 185                 ecb.out_hunk = xdiff_out_hunk;
 186         ecb.out_line = xdiff_outf;
 187         ecb.priv = &state;
 188         strbuf_init(&state.remainder, 0);
 189         ret = xdi_diff(mf1, mf2, xpp, xecfg, &ecb);
 190         strbuf_release(&state.remainder);
 191         return ret;
 192 }
 193
 194 int read_mmfile(mmfile_t *ptr, const char *filename)
 195 {
 196         struct stat st;
 197         FILE *f;
 198         size_t sz;
 199
 200         if (stat(filename, &st))
 201                 return error_errno("Could not stat %s", filename);
 202         if ((f = fopen(filename, "rb")) == NULL)
 203                 return error_errno("Could not open %s", filename);
 204         sz = xsize_t(st.st_size);
 205         ptr->ptr = xmalloc(sz ? sz : 1);
 206         if (sz && fread(ptr->ptr, sz, 1, f) != 1) {
 207                 fclose(f);
 208                 return error("Could not read %s", filename);
 209         }
 210         fclose(f);
 211         ptr->size = sz;
 212         return 0;
 213 }
 214
 215 void read_mmblob(mmfile_t *ptr, const struct object_id *oid)
 216 {
 217         unsigned long size;
 218         enum object_type type;
 219
 220         if (!oidcmp(oid, &null_oid)) {
 221                 ptr->ptr = xstrdup("");
 222                 ptr->size = 0;
 223                 return;
 224         }
 225
 226         ptr->ptr = read_object_file(oid, &type, &size);
 227         if (!ptr->ptr || type != OBJ_BLOB)
 228                 die("unable to read blob object %s", oid_to_hex(oid));
 229         ptr->size = size;
 230 }
 231
 232 #define FIRST_FEW_BYTES 8000
 233 int buffer_is_binary(const char *ptr, unsigned long size)
 234 {
 235         if (FIRST_FEW_BYTES < size)
 236                 size = FIRST_FEW_BYTES;
 237         return !!memchr(ptr, 0, size);
 238 }
 239
 240 struct ff_regs {
 241         int nr;
 242         struct ff_reg {
 243                 regex_t re;
 244                 int negate;
 245         } *array;
 246 };
 247
 248 static long ff_regexp(const char *line, long len,
 249                 char *buffer, long buffer_size, void *priv)
 250 {
 251         struct ff_regs *regs = priv;
 252         regmatch_t pmatch[2];
 253         int i;
 254         int result;
 255
 256         /* Exclude terminating newline (and cr) from matching */
 257         if (len > 0 && line[len-1] == '\n') {
 258                 if (len > 1 && line[len-2] == '\r')
 259                         len -= 2;
 260                 else
 261                         len--;
 262         }
 263
 264         for (i = 0; i < regs->nr; i++) {
 265                 struct ff_reg *reg = regs->array + i;
 266                 if (!regexec_buf(&reg->re, line, len, 2, pmatch, 0)) {
 267                         if (reg->negate)
 268                                 return -1;
 269                         break;
 270                 }
 271         }
 272         if (regs->nr <= i)
 273                 return -1;
 274         i = pmatch[1].rm_so >= 0 ? 1 : 0;
 275         line += pmatch[i].rm_so;
 276         result = pmatch[i].rm_eo - pmatch[i].rm_so;
 277         if (result > buffer_size)
 278                 result = buffer_size;
 279         while (result > 0 && (isspace(line[result - 1])))
 280                 result--;
 281         memcpy(buffer, line, result);
 282         return result;
 283 }
 284
 285 void xdiff_set_find_func(xdemitconf_t *xecfg, const char *value, int cflags)
 286 {
 287         int i;
 288         struct ff_regs *regs;
 289
 290         xecfg->find_func = ff_regexp;
 291         regs = xecfg->find_func_priv = xmalloc(sizeof(struct ff_regs));
 292         for (i = 0, regs->nr = 1; value[i]; i++)
 293                 if (value[i] == '\n')
 294                         regs->nr++;
 295         ALLOC_ARRAY(regs->array, regs->nr);
 296         for (i = 0; i < regs->nr; i++) {
 297                 struct ff_reg *reg = regs->array + i;
 298                 const char *ep = strchr(value, '\n'), *expression;
 299                 char *buffer = NULL;
 300
 301                 reg->negate = (*value == '!');
 302                 if (reg->negate && i == regs->nr - 1)
 303                         die("Last expression must not be negated: %s", value);
 304                 if (*value == '!')
 305                         value++;
 306                 if (ep)
 307                         expression = buffer = xstrndup(value, ep - value);
 308                 else
 309                         expression = value;
 310                 if (regcomp(&reg->re, expression, cflags))
 311                         die("Invalid regexp to look for hunk header: %s", expression);
 312                 free(buffer);
 313                 value = ep + 1;
 314         }
 315 }
 316
 317 void xdiff_clear_find_func(xdemitconf_t *xecfg)
 318 {
 319         if (xecfg->find_func) {
 320                 int i;
 321                 struct ff_regs *regs = xecfg->find_func_priv;
 322
 323                 for (i = 0; i < regs->nr; i++)
 324                         regfree(&regs->array[i].re);
 325                 free(regs->array);
 326                 free(regs);
 327                 xecfg->find_func = NULL;
 328                 xecfg->find_func_priv = NULL;
 329         }
 330 }
 331
 332 unsigned long xdiff_hash_string(const char *s, size_t len, long flags)
 333 {
 334         return xdl_hash_record(&s, s + len, flags);
 335 }
 336
 337 int xdiff_compare_lines(const char *l1, long s1,
 338                         const char *l2, long s2, long flags)
 339 {
 340         return xdl_recmatch(l1, s1, l2, s2, flags);
 341 }
 342
 343 int git_xmerge_style = -1;
 344
 345 int git_xmerge_config(const char *var, const char *value, void *cb)
 346 {
 347         if (!strcmp(var, "merge.conflictstyle")) {
 348                 if (!value)
 349                         die("'%s' is not a boolean", var);
 350                 if (!strcmp(value, "diff3"))
 351                         git_xmerge_style = XDL_MERGE_DIFF3;
 352                 else if (!strcmp(value, "merge"))
 353                         git_xmerge_style = 0;
 354                 else
 355                         die("unknown style '%s' given for '%s'",
 356                             value, var);
 357                 return 0;
 358         }
 359         return git_default_config(var, value, cb);
 360 }