xdiff-interface.c

   1 #include "git-compat-util.h"
   2 #include "gettext.h"
   3 #include "config.h"
   4 #include "hex.h"
   5 #include "object-store-ll.h"
   6 #include "strbuf.h"
   7 #include "xdiff-interface.h"
   8 #include "xdiff/xtypes.h"
   9 #include "xdiff/xdiffi.h"
  10 #include "xdiff/xutils.h"
  11
  12 struct xdiff_emit_state {
  13         xdiff_emit_hunk_fn hunk_fn;
  14         xdiff_emit_line_fn line_fn;
  15         void *consume_callback_data;
  16         struct strbuf remainder;
  17 };
  18
  19 static int xdiff_out_hunk(void *priv_,
  20                           long old_begin, long old_nr,
  21                           long new_begin, long new_nr,
  22                           const char *func, long funclen)
  23 {
  24         struct xdiff_emit_state *priv = priv_;
  25
  26         if (priv->remainder.len)
  27                 BUG("xdiff emitted hunk in the middle of a line");
  28
  29         priv->hunk_fn(priv->consume_callback_data,
  30                       old_begin, old_nr, new_begin, new_nr,
  31                       func, funclen);
  32         return 0;
  33 }
  34
  35 static int consume_one(void *priv_, char *s, unsigned long size)
  36 {
  37         struct xdiff_emit_state *priv = priv_;
  38         char *ep;
  39         while (size) {
  40                 unsigned long this_size;
  41                 int ret;
  42                 ep = memchr(s, '\n', size);
  43                 this_size = (ep == NULL) ? size : (ep - s + 1);
  44                 ret = priv->line_fn(priv->consume_callback_data, s, this_size);
  45                 if (ret)
  46                         return ret;
  47                 size -= this_size;
  48                 s += this_size;
  49         }
  50         return 0;
  51 }
  52
  53 static int xdiff_outf(void *priv_, mmbuffer_t *mb, int nbuf)
  54 {
  55         struct xdiff_emit_state *priv = priv_;
  56         int i;
  57         int stop = 0;
  58
  59         if (!priv->line_fn)
  60                 return 0;
  61
  62         for (i = 0; i < nbuf; i++) {
  63                 if (stop)
  64                         return 1;
  65                 if (mb[i].ptr[mb[i].size-1] != '\n') {
  66                         /* Incomplete line */
  67                         strbuf_add(&priv->remainder, mb[i].ptr, mb[i].size);
  68                         continue;
  69                 }
  70
  71                 /* we have a complete line */
  72                 if (!priv->remainder.len) {
  73                         stop = consume_one(priv, mb[i].ptr, mb[i].size);
  74                         continue;
  75                 }
  76                 strbuf_add(&priv->remainder, mb[i].ptr, mb[i].size);
  77                 stop = consume_one(priv, priv->remainder.buf, priv->remainder.len);
  78                 strbuf_reset(&priv->remainder);
  79         }
  80         if (stop)
  81                 return -1;
  82         if (priv->remainder.len) {
  83                 stop = consume_one(priv, priv->remainder.buf, priv->remainder.len);
  84                 strbuf_reset(&priv->remainder);
  85         }
  86         if (stop)
  87                 return -1;
  88         return 0;
  89 }
  90
  91 /*
  92  * Trim down common substring at the end of the buffers,
  93  * but end on a complete line.
  94  */
  95 static void trim_common_tail(mmfile_t *a, mmfile_t *b)
  96 {
  97         const int blk = 1024;
  98         long trimmed = 0, recovered = 0;
  99         char *ap = a->size ? a->ptr + a->size : a->ptr;
 100         char *bp = b->size ? b->ptr + b->size : b->ptr;
 101         long smaller = (a->size < b->size) ? a->size : b->size;
 102
 103         while (blk + trimmed <= smaller && !memcmp(ap - blk, bp - blk, blk)) {
 104                 trimmed += blk;
 105                 ap -= blk;
 106                 bp -= blk;
 107         }
 108
 109         while (recovered < trimmed)
 110                 if (ap[recovered++] == '\n')
 111                         break;
 112         a->size -= trimmed - recovered;
 113         b->size -= trimmed - recovered;
 114 }
 115
 116 int xdi_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp, xdemitconf_t const *xecfg, xdemitcb_t *xecb)
 117 {
 118         mmfile_t a = *mf1;
 119         mmfile_t b = *mf2;
 120
 121         if (mf1->size > MAX_XDIFF_SIZE || mf2->size > MAX_XDIFF_SIZE)
 122                 return -1;
 123
 124         if (!xecfg->ctxlen && !(xecfg->flags & XDL_EMIT_FUNCCONTEXT))
 125                 trim_common_tail(&a, &b);
 126
 127         return xdl_diff(&a, &b, xpp, xecfg, xecb);
 128 }
 129
 130 int xdi_diff_outf(mmfile_t *mf1, mmfile_t *mf2,
 131                   xdiff_emit_hunk_fn hunk_fn,
 132                   xdiff_emit_line_fn line_fn,
 133                   void *consume_callback_data,
 134                   xpparam_t const *xpp, xdemitconf_t const *xecfg)
 135 {
 136         int ret;
 137         struct xdiff_emit_state state;
 138         xdemitcb_t ecb;
 139
 140         memset(&state, 0, sizeof(state));
 141         state.hunk_fn = hunk_fn;
 142         state.line_fn = line_fn;
 143         state.consume_callback_data = consume_callback_data;
 144         memset(&ecb, 0, sizeof(ecb));
 145         if (hunk_fn)
 146                 ecb.out_hunk = xdiff_out_hunk;
 147         ecb.out_line = xdiff_outf;
 148         ecb.priv = &state;
 149         strbuf_init(&state.remainder, 0);
 150         ret = xdi_diff(mf1, mf2, xpp, xecfg, &ecb);
 151         strbuf_release(&state.remainder);
 152         return ret;
 153 }
 154
 155 int read_mmfile(mmfile_t *ptr, const char *filename)
 156 {
 157         struct stat st;
 158         FILE *f;
 159         size_t sz;
 160
 161         if (stat(filename, &st))
 162                 return error_errno("Could not stat %s", filename);
 163         if (!(f = fopen(filename, "rb")))
 164                 return error_errno("Could not open %s", filename);
 165         sz = xsize_t(st.st_size);
 166         ptr->ptr = xmalloc(sz ? sz : 1);
 167         if (sz && fread(ptr->ptr, sz, 1, f) != 1) {
 168                 fclose(f);
 169                 return error("Could not read %s", filename);
 170         }
 171         fclose(f);
 172         ptr->size = sz;
 173         return 0;
 174 }
 175
 176 void read_mmblob(mmfile_t *ptr, const struct object_id *oid)
 177 {
 178         unsigned long size;
 179         enum object_type type;
 180
 181         if (oideq(oid, null_oid())) {
 182                 ptr->ptr = xstrdup("");
 183                 ptr->size = 0;
 184                 return;
 185         }
 186
 187         ptr->ptr = repo_read_object_file(the_repository, oid, &type, &size);
 188         if (!ptr->ptr || type != OBJ_BLOB)
 189                 die("unable to read blob object %s", oid_to_hex(oid));
 190         ptr->size = size;
 191 }
 192
 193 #define FIRST_FEW_BYTES 8000
 194 int buffer_is_binary(const char *ptr, unsigned long size)
 195 {
 196         if (FIRST_FEW_BYTES < size)
 197                 size = FIRST_FEW_BYTES;
 198         return !!memchr(ptr, 0, size);
 199 }
 200
 201 struct ff_regs {
 202         int nr;
 203         struct ff_reg {
 204                 regex_t re;
 205                 int negate;
 206         } *array;
 207 };
 208
 209 static long ff_regexp(const char *line, long len,
 210                 char *buffer, long buffer_size, void *priv)
 211 {
 212         struct ff_regs *regs = priv;
 213         regmatch_t pmatch[2];
 214         int i;
 215         int result;
 216
 217         /* Exclude terminating newline (and cr) from matching */
 218         if (len > 0 && line[len-1] == '\n') {
 219                 if (len > 1 && line[len-2] == '\r')
 220                         len -= 2;
 221                 else
 222                         len--;
 223         }
 224
 225         for (i = 0; i < regs->nr; i++) {
 226                 struct ff_reg *reg = regs->array + i;
 227                 if (!regexec_buf(&reg->re, line, len, 2, pmatch, 0)) {
 228                         if (reg->negate)
 229                                 return -1;
 230                         break;
 231                 }
 232         }
 233         if (regs->nr <= i)
 234                 return -1;
 235         i = pmatch[1].rm_so >= 0 ? 1 : 0;
 236         line += pmatch[i].rm_so;
 237         result = pmatch[i].rm_eo - pmatch[i].rm_so;
 238         if (result > buffer_size)
 239                 result = buffer_size;
 240         while (result > 0 && (isspace(line[result - 1])))
 241                 result--;
 242         memcpy(buffer, line, result);
 243         return result;
 244 }
 245
 246 void xdiff_set_find_func(xdemitconf_t *xecfg, const char *value, int cflags)
 247 {
 248         int i;
 249         struct ff_regs *regs;
 250
 251         xecfg->find_func = ff_regexp;
 252         regs = xecfg->find_func_priv = xmalloc(sizeof(struct ff_regs));
 253         for (i = 0, regs->nr = 1; value[i]; i++)
 254                 if (value[i] == '\n')
 255                         regs->nr++;
 256         ALLOC_ARRAY(regs->array, regs->nr);
 257         for (i = 0; i < regs->nr; i++) {
 258                 struct ff_reg *reg = regs->array + i;
 259                 const char *ep, *expression;
 260                 char *buffer = NULL;
 261
 262                 if (!value)
 263                         BUG("mismatch between line count and parsing");
 264                 ep = strchr(value, '\n');
 265
 266                 reg->negate = (*value == '!');
 267                 if (reg->negate && i == regs->nr - 1)
 268                         die("Last expression must not be negated: %s", value);
 269                 if (*value == '!')
 270                         value++;
 271                 if (ep)
 272                         expression = buffer = xstrndup(value, ep - value);
 273                 else
 274                         expression = value;
 275                 if (regcomp(&reg->re, expression, cflags))
 276                         die("Invalid regexp to look for hunk header: %s", expression);
 277                 free(buffer);
 278                 value = ep ? ep + 1 : NULL;
 279         }
 280 }
 281
 282 void xdiff_clear_find_func(xdemitconf_t *xecfg)
 283 {
 284         if (xecfg->find_func) {
 285                 int i;
 286                 struct ff_regs *regs = xecfg->find_func_priv;
 287
 288                 for (i = 0; i < regs->nr; i++)
 289                         regfree(&regs->array[i].re);
 290                 free(regs->array);
 291                 free(regs);
 292                 xecfg->find_func = NULL;
 293                 xecfg->find_func_priv = NULL;
 294         }
 295 }
 296
 297 unsigned long xdiff_hash_string(const char *s, size_t len, long flags)
 298 {
 299         return xdl_hash_record(&s, s + len, flags);
 300 }
 301
 302 int xdiff_compare_lines(const char *l1, long s1,
 303                         const char *l2, long s2, long flags)
 304 {
 305         return xdl_recmatch(l1, s1, l2, s2, flags);
 306 }
 307
 308 int parse_conflict_style_name(const char *value)
 309 {
 310         if (!strcmp(value, "diff3"))
 311                 return XDL_MERGE_DIFF3;
 312         else if (!strcmp(value, "zdiff3"))
 313                 return XDL_MERGE_ZEALOUS_DIFF3;
 314         else if (!strcmp(value, "merge"))
 315                 return 0;
 316         /*
 317          * Please update _git_checkout() in git-completion.bash when
 318          * you add new merge config
 319          */
 320         else
 321                 return -1;
 322 }
 323
 324 int git_xmerge_style = -1;
 325
 326 int git_xmerge_config(const char *var, const char *value,
 327                       const struct config_context *ctx, void *cb)
 328 {
 329         if (!strcmp(var, "merge.conflictstyle")) {
 330                 if (!value)
 331                         return config_error_nonbool(var);
 332                 git_xmerge_style = parse_conflict_style_name(value);
 333                 if (git_xmerge_style == -1)
 334                         return error(_("unknown style '%s' given for '%s'"),
 335                                      value, var);
 336                 return 0;
 337         }
 338         return git_default_config(var, value, ctx, cb);
 339 }