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         trim_common_tail(&a, &b, xecfg->ctxlen);
 135
 136         return xdl_diff(&a, &b, xpp, xecfg, xecb);
 137 }
 138
 139 int xdi_diff_outf(mmfile_t *mf1, mmfile_t *mf2,
 140                   xdiff_emit_consume_fn fn, void *consume_callback_data,
 141                   xpparam_t const *xpp, xdemitconf_t const *xecfg)
 142 {
 143         int ret;
 144         struct xdiff_emit_state state;
 145         xdemitcb_t ecb;
 146
 147         memset(&state, 0, sizeof(state));
 148         state.consume = fn;
 149         state.consume_callback_data = consume_callback_data;
 150         memset(&ecb, 0, sizeof(ecb));
 151         ecb.outf = xdiff_outf;
 152         ecb.priv = &state;
 153         strbuf_init(&state.remainder, 0);
 154         ret = xdi_diff(mf1, mf2, xpp, xecfg, &ecb);
 155         strbuf_release(&state.remainder);
 156         return ret;
 157 }
 158
 159 int read_mmfile(mmfile_t *ptr, const char *filename)
 160 {
 161         struct stat st;
 162         FILE *f;
 163         size_t sz;
 164
 165         if (stat(filename, &st))
 166                 return error("Could not stat %s", filename);
 167         if ((f = fopen(filename, "rb")) == NULL)
 168                 return error("Could not open %s", filename);
 169         sz = xsize_t(st.st_size);
 170         ptr->ptr = xmalloc(sz ? sz : 1);
 171         if (sz && fread(ptr->ptr, sz, 1, f) != 1) {
 172                 fclose(f);
 173                 return error("Could not read %s", filename);
 174         }
 175         fclose(f);
 176         ptr->size = sz;
 177         return 0;
 178 }
 179
 180 void read_mmblob(mmfile_t *ptr, const unsigned char *sha1)
 181 {
 182         unsigned long size;
 183         enum object_type type;
 184
 185         if (!hashcmp(sha1, null_sha1)) {
 186                 ptr->ptr = xstrdup("");
 187                 ptr->size = 0;
 188                 return;
 189         }
 190
 191         ptr->ptr = read_sha1_file(sha1, &type, &size);
 192         if (!ptr->ptr || type != OBJ_BLOB)
 193                 die("unable to read blob object %s", sha1_to_hex(sha1));
 194         ptr->size = size;
 195 }
 196
 197 #define FIRST_FEW_BYTES 8000
 198 int buffer_is_binary(const char *ptr, unsigned long size)
 199 {
 200         if (FIRST_FEW_BYTES < size)
 201                 size = FIRST_FEW_BYTES;
 202         return !!memchr(ptr, 0, size);
 203 }
 204
 205 struct ff_regs {
 206         int nr;
 207         struct ff_reg {
 208                 regex_t re;
 209                 int negate;
 210         } *array;
 211 };
 212
 213 static long ff_regexp(const char *line, long len,
 214                 char *buffer, long buffer_size, void *priv)
 215 {
 216         char *line_buffer;
 217         struct ff_regs *regs = priv;
 218         regmatch_t pmatch[2];
 219         int i;
 220         int result = -1;
 221
 222         /* Exclude terminating newline (and cr) from matching */
 223         if (len > 0 && line[len-1] == '\n') {
 224                 if (len > 1 && line[len-2] == '\r')
 225                         len -= 2;
 226                 else
 227                         len--;
 228         }
 229
 230         line_buffer = xstrndup(line, len); /* make NUL terminated */
 231
 232         for (i = 0; i < regs->nr; i++) {
 233                 struct ff_reg *reg = regs->array + i;
 234                 if (!regexec(&reg->re, line_buffer, 2, pmatch, 0)) {
 235                         if (reg->negate)
 236                                 goto fail;
 237                         break;
 238                 }
 239         }
 240         if (regs->nr <= i)
 241                 goto fail;
 242         i = pmatch[1].rm_so >= 0 ? 1 : 0;
 243         line += pmatch[i].rm_so;
 244         result = pmatch[i].rm_eo - pmatch[i].rm_so;
 245         if (result > buffer_size)
 246                 result = buffer_size;
 247         while (result > 0 && (isspace(line[result - 1])))
 248                 result--;
 249         memcpy(buffer, line, result);
 250  fail:
 251         free(line_buffer);
 252         return result;
 253 }
 254
 255 void xdiff_set_find_func(xdemitconf_t *xecfg, const char *value, int cflags)
 256 {
 257         int i;
 258         struct ff_regs *regs;
 259
 260         xecfg->find_func = ff_regexp;
 261         regs = xecfg->find_func_priv = xmalloc(sizeof(struct ff_regs));
 262         for (i = 0, regs->nr = 1; value[i]; i++)
 263                 if (value[i] == '\n')
 264                         regs->nr++;
 265         regs->array = xmalloc(regs->nr * sizeof(struct ff_reg));
 266         for (i = 0; i < regs->nr; i++) {
 267                 struct ff_reg *reg = regs->array + i;
 268                 const char *ep = strchr(value, '\n'), *expression;
 269                 char *buffer = NULL;
 270
 271                 reg->negate = (*value == '!');
 272                 if (reg->negate && i == regs->nr - 1)
 273                         die("Last expression must not be negated: %s", value);
 274                 if (*value == '!')
 275                         value++;
 276                 if (ep)
 277                         expression = buffer = xstrndup(value, ep - value);
 278                 else
 279                         expression = value;
 280                 if (regcomp(&reg->re, expression, cflags))
 281                         die("Invalid regexp to look for hunk header: %s", expression);
 282                 free(buffer);
 283                 value = ep + 1;
 284         }
 285 }
 286
 287 void xdiff_clear_find_func(xdemitconf_t *xecfg)
 288 {
 289         if (xecfg->find_func) {
 290                 int i;
 291                 struct ff_regs *regs = xecfg->find_func_priv;
 292
 293                 for (i = 0; i < regs->nr; i++)
 294                         regfree(&regs->array[i].re);
 295                 free(regs->array);
 296                 free(regs);
 297                 xecfg->find_func = NULL;
 298                 xecfg->find_func_priv = NULL;
 299         }
 300 }
 301
 302 int git_xmerge_style = -1;
 303
 304 int git_xmerge_config(const char *var, const char *value, void *cb)
 305 {
 306         if (!strcmp(var, "merge.conflictstyle")) {
 307                 if (!value)
 308                         die("'%s' is not a boolean", var);
 309                 if (!strcmp(value, "diff3"))
 310                         git_xmerge_style = XDL_MERGE_DIFF3;
 311                 else if (!strcmp(value, "merge"))
 312                         git_xmerge_style = 0;
 313                 else
 314                         die("unknown style '%s' given for '%s'",
 315                             value, var);
 316                 return 0;
 317         }
 318         return git_default_config(var, value, cb);
 319 }