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