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