xdiff-interface.c

   1 #include "cache.h"
   2 #include "xdiff-interface.h"
   3 #include "xdiff/xtypes.h"
   4 #include "xdiff/xdiffi.h"
   5 #include "xdiff/xemit.h"
   6 #include "xdiff/xmacros.h"
   7
   8 struct xdiff_emit_state {
   9         xdiff_emit_consume_fn consume;
  10         void *consume_callback_data;
  11         struct strbuf remainder;
  12 };
  13
  14 static int parse_num(char **cp_p, int *num_p)
  15 {
  16         char *cp = *cp_p;
  17         int num = 0;
  18
  19         while ('0' <= *cp && *cp <= '9')
  20                 num = num * 10 + *cp++ - '0';
  21         if (!(cp - *cp_p))
  22                 return -1;
  23         *cp_p = cp;
  24         *num_p = num;
  25         return 0;
  26 }
  27
  28 int parse_hunk_header(char *line, int len,
  29                       int *ob, int *on,
  30                       int *nb, int *nn)
  31 {
  32         char *cp;
  33         cp = line + 4;
  34         if (parse_num(&cp, ob)) {
  35         bad_line:
  36                 return error("malformed diff output: %s", line);
  37         }
  38         if (*cp == ',') {
  39                 cp++;
  40                 if (parse_num(&cp, on))
  41                         goto bad_line;
  42         }
  43         else
  44                 *on = 1;
  45         if (*cp++ != ' ' || *cp++ != '+')
  46                 goto bad_line;
  47         if (parse_num(&cp, nb))
  48                 goto bad_line;
  49         if (*cp == ',') {
  50                 cp++;
  51                 if (parse_num(&cp, nn))
  52                         goto bad_line;
  53         }
  54         else
  55                 *nn = 1;
  56         return -!!memcmp(cp, " @@", 3);
  57 }
  58
  59 static void consume_one(void *priv_, char *s, unsigned long size)
  60 {
  61         struct xdiff_emit_state *priv = priv_;
  62         char *ep;
  63         while (size) {
  64                 unsigned long this_size;
  65                 ep = memchr(s, '\n', size);
  66                 this_size = (ep == NULL) ? size : (ep - s + 1);
  67                 priv->consume(priv->consume_callback_data, s, this_size);
  68                 size -= this_size;
  69                 s += this_size;
  70         }
  71 }
  72
  73 static int xdiff_outf(void *priv_, mmbuffer_t *mb, int nbuf)
  74 {
  75         struct xdiff_emit_state *priv = priv_;
  76         int i;
  77
  78         for (i = 0; i < nbuf; i++) {
  79                 if (mb[i].ptr[mb[i].size-1] != '\n') {
  80                         /* Incomplete line */
  81                         strbuf_add(&priv->remainder, mb[i].ptr, mb[i].size);
  82                         continue;
  83                 }
  84
  85                 /* we have a complete line */
  86                 if (!priv->remainder.len) {
  87                         consume_one(priv, mb[i].ptr, mb[i].size);
  88                         continue;
  89                 }
  90                 strbuf_add(&priv->remainder, mb[i].ptr, mb[i].size);
  91                 consume_one(priv, priv->remainder.buf, priv->remainder.len);
  92                 strbuf_reset(&priv->remainder);
  93         }
  94         if (priv->remainder.len) {
  95                 consume_one(priv, priv->remainder.buf, priv->remainder.len);
  96                 strbuf_reset(&priv->remainder);
  97         }
  98         return 0;
  99 }
 100
 101 /*
 102  * Trim down common substring at the end of the buffers,
 103  * but leave at least ctx lines at the end.
 104  */
 105 static void trim_common_tail(mmfile_t *a, mmfile_t *b, long ctx)
 106 {
 107         const int blk = 1024;
 108         long trimmed = 0, recovered = 0;
 109         char *ap = a->ptr + a->size;
 110         char *bp = b->ptr + b->size;
 111         long smaller = (a->size < b->size) ? a->size : b->size;
 112
 113         if (ctx)
 114                 return;
 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         trim_common_tail(&a, &b, xecfg->ctxlen);
 138
 139         return xdl_diff(&a, &b, xpp, xecfg, xecb);
 140 }
 141
 142 int xdi_diff_outf(mmfile_t *mf1, mmfile_t *mf2,
 143                   xdiff_emit_consume_fn fn, void *consume_callback_data,
 144                   xpparam_t const *xpp, xdemitconf_t const *xecfg)
 145 {
 146         int ret;
 147         struct xdiff_emit_state state;
 148         xdemitcb_t ecb;
 149
 150         memset(&state, 0, sizeof(state));
 151         state.consume = fn;
 152         state.consume_callback_data = consume_callback_data;
 153         memset(&ecb, 0, sizeof(ecb));
 154         ecb.outf = xdiff_outf;
 155         ecb.priv = &state;
 156         strbuf_init(&state.remainder, 0);
 157         ret = xdi_diff(mf1, mf2, xpp, xecfg, &ecb);
 158         strbuf_release(&state.remainder);
 159         return ret;
 160 }
 161
 162 int read_mmfile(mmfile_t *ptr, const char *filename)
 163 {
 164         struct stat st;
 165         FILE *f;
 166         size_t sz;
 167
 168         if (stat(filename, &st))
 169                 return error("Could not stat %s", filename);
 170         if ((f = fopen(filename, "rb")) == NULL)
 171                 return error("Could not open %s", filename);
 172         sz = xsize_t(st.st_size);
 173         ptr->ptr = xmalloc(sz ? sz : 1);
 174         if (sz && fread(ptr->ptr, sz, 1, f) != 1) {
 175                 fclose(f);
 176                 return error("Could not read %s", filename);
 177         }
 178         fclose(f);
 179         ptr->size = sz;
 180         return 0;
 181 }
 182
 183 void read_mmblob(mmfile_t *ptr, const unsigned char *sha1)
 184 {
 185         unsigned long size;
 186         enum object_type type;
 187
 188         if (!hashcmp(sha1, null_sha1)) {
 189                 ptr->ptr = xstrdup("");
 190                 ptr->size = 0;
 191                 return;
 192         }
 193
 194         ptr->ptr = read_sha1_file(sha1, &type, &size);
 195         if (!ptr->ptr || type != OBJ_BLOB)
 196                 die("unable to read blob object %s", sha1_to_hex(sha1));
 197         ptr->size = size;
 198 }
 199
 200 #define FIRST_FEW_BYTES 8000
 201 int buffer_is_binary(const char *ptr, unsigned long size)
 202 {
 203         if (FIRST_FEW_BYTES < size)
 204                 size = FIRST_FEW_BYTES;
 205         return !!memchr(ptr, 0, size);
 206 }
 207
 208 struct ff_regs {
 209         int nr;
 210         struct ff_reg {
 211                 regex_t re;
 212                 int negate;
 213         } *array;
 214 };
 215
 216 static long ff_regexp(const char *line, long len,
 217                 char *buffer, long buffer_size, void *priv)
 218 {
 219         char *line_buffer;
 220         struct ff_regs *regs = priv;
 221         regmatch_t pmatch[2];
 222         int i;
 223         int result = -1;
 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         line_buffer = xstrndup(line, len); /* make NUL terminated */
 234
 235         for (i = 0; i < regs->nr; i++) {
 236                 struct ff_reg *reg = regs->array + i;
 237                 if (!regexec(&reg->re, line_buffer, 2, pmatch, 0)) {
 238                         if (reg->negate)
 239                                 goto fail;
 240                         break;
 241                 }
 242         }
 243         if (regs->nr <= i)
 244                 goto fail;
 245         i = pmatch[1].rm_so >= 0 ? 1 : 0;
 246         line += pmatch[i].rm_so;
 247         result = pmatch[i].rm_eo - pmatch[i].rm_so;
 248         if (result > buffer_size)
 249                 result = buffer_size;
 250         while (result > 0 && (isspace(line[result - 1])))
 251                 result--;
 252         memcpy(buffer, line, result);
 253  fail:
 254         free(line_buffer);
 255         return result;
 256 }
 257
 258 void xdiff_set_find_func(xdemitconf_t *xecfg, const char *value, int cflags)
 259 {
 260         int i;
 261         struct ff_regs *regs;
 262
 263         xecfg->find_func = ff_regexp;
 264         regs = xecfg->find_func_priv = xmalloc(sizeof(struct ff_regs));
 265         for (i = 0, regs->nr = 1; value[i]; i++)
 266                 if (value[i] == '\n')
 267                         regs->nr++;
 268         regs->array = xmalloc(regs->nr * sizeof(struct ff_reg));
 269         for (i = 0; i < regs->nr; i++) {
 270                 struct ff_reg *reg = regs->array + i;
 271                 const char *ep = strchr(value, '\n'), *expression;
 272                 char *buffer = NULL;
 273
 274                 reg->negate = (*value == '!');
 275                 if (reg->negate && i == regs->nr - 1)
 276                         die("Last expression must not be negated: %s", value);
 277                 if (*value == '!')
 278                         value++;
 279                 if (ep)
 280                         expression = buffer = xstrndup(value, ep - value);
 281                 else
 282                         expression = value;
 283                 if (regcomp(&reg->re, expression, cflags))
 284                         die("Invalid regexp to look for hunk header: %s", expression);
 285                 free(buffer);
 286                 value = ep + 1;
 287         }
 288 }
 289
 290 void xdiff_clear_find_func(xdemitconf_t *xecfg)
 291 {
 292         if (xecfg->find_func) {
 293                 int i;
 294                 struct ff_regs *regs = xecfg->find_func_priv;
 295
 296                 for (i = 0; i < regs->nr; i++)
 297                         regfree(&regs->array[i].re);
 298                 free(regs->array);
 299                 free(regs);
 300                 xecfg->find_func = NULL;
 301                 xecfg->find_func_priv = NULL;
 302         }
 303 }
 304
 305 int git_xmerge_style = -1;
 306
 307 int git_xmerge_config(const char *var, const char *value, void *cb)
 308 {
 309         if (!strcmp(var, "merge.conflictstyle")) {
 310                 if (!value)
 311                         die("'%s' is not a boolean", var);
 312                 if (!strcmp(value, "diff3"))
 313                         git_xmerge_style = XDL_MERGE_DIFF3;
 314                 else if (!strcmp(value, "merge"))
 315                         git_xmerge_style = 0;
 316                 else
 317                         die("unknown style '%s' given for '%s'",
 318                             value, var);
 319                 return 0;
 320         }
 321         return git_default_config(var, value, cb);
 322 }