xdiff-interface.c

   1 #define USE_THE_REPOSITORY_VARIABLE
   2 #define DISABLE_SIGN_COMPARE_WARNINGS
   3
   4 #include "git-compat-util.h"
   5 #include "gettext.h"
   6 #include "config.h"
   7 #include "hex.h"
   8 #include "odb.h"
   9 #include "strbuf.h"
  10 #include "xdiff-interface.h"
  11 #include "xdiff/xtypes.h"
  12 #include "xdiff/xdiffi.h"
  13 #include "xdiff/xutils.h"
  14
  15 struct xdiff_emit_state {
  16         xdiff_emit_hunk_fn hunk_fn;
  17         xdiff_emit_line_fn line_fn;
  18         void *consume_callback_data;
  19         struct strbuf remainder;
  20 };
  21
  22 static int xdiff_out_hunk(void *priv_,
  23                           long old_begin, long old_nr,
  24                           long new_begin, long new_nr,
  25                           const char *func, long funclen)
  26 {
  27         struct xdiff_emit_state *priv = priv_;
  28
  29         if (priv->remainder.len)
  30                 BUG("xdiff emitted hunk in the middle of a line");
  31
  32         priv->hunk_fn(priv->consume_callback_data,
  33                       old_begin, old_nr, new_begin, new_nr,
  34                       func, funclen);
  35         return 0;
  36 }
  37
  38 static int consume_one(void *priv_, char *s, unsigned long size)
  39 {
  40         struct xdiff_emit_state *priv = priv_;
  41         char *ep;
  42         while (size) {
  43                 unsigned long this_size;
  44                 int ret;
  45                 ep = memchr(s, '\n', size);
  46                 this_size = (ep == NULL) ? size : (ep - s + 1);
  47                 ret = priv->line_fn(priv->consume_callback_data, s, this_size);
  48                 if (ret)
  49                         return ret;
  50                 size -= this_size;
  51                 s += this_size;
  52         }
  53         return 0;
  54 }
  55
  56 static int xdiff_outf(void *priv_, mmbuffer_t *mb, int nbuf)
  57 {
  58         struct xdiff_emit_state *priv = priv_;
  59         int i;
  60         int stop = 0;
  61
  62         if (!priv->line_fn)
  63                 return 0;
  64
  65         for (i = 0; i < nbuf; i++) {
  66                 if (stop)
  67                         return 1;
  68                 if (mb[i].ptr[mb[i].size-1] != '\n') {
  69                         /* Incomplete line */
  70                         strbuf_add(&priv->remainder, mb[i].ptr, mb[i].size);
  71                         continue;
  72                 }
  73
  74                 /* we have a complete line */
  75                 if (!priv->remainder.len) {
  76                         stop = consume_one(priv, mb[i].ptr, mb[i].size);
  77                         continue;
  78                 }
  79                 strbuf_add(&priv->remainder, mb[i].ptr, mb[i].size);
  80                 stop = consume_one(priv, priv->remainder.buf, priv->remainder.len);
  81                 strbuf_reset(&priv->remainder);
  82         }
  83         if (stop)
  84                 return -1;
  85         if (priv->remainder.len) {
  86                 stop = consume_one(priv, priv->remainder.buf, priv->remainder.len);
  87                 strbuf_reset(&priv->remainder);
  88         }
  89         if (stop)
  90                 return -1;
  91         return 0;
  92 }
  93
  94 /*
  95  * Trim down common substring at the end of the buffers,
  96  * but end on a complete line.
  97  */
  98 static void trim_common_tail(mmfile_t *a, mmfile_t *b)
  99 {
 100         const int blk = 1024;
 101         long trimmed = 0, recovered = 0;
 102         char *ap = a->size ? a->ptr + a->size : a->ptr;
 103         char *bp = b->size ? b->ptr + b->size : b->ptr;
 104         long smaller = (a->size < b->size) ? a->size : b->size;
 105
 106         while (blk + trimmed <= smaller && !memcmp(ap - blk, bp - blk, blk)) {
 107                 trimmed += blk;
 108                 ap -= blk;
 109                 bp -= blk;
 110         }
 111
 112         while (recovered < trimmed)
 113                 if (ap[recovered++] == '\n')
 114                         break;
 115         a->size -= trimmed - recovered;
 116         b->size -= trimmed - recovered;
 117 }
 118
 119 int xdi_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp, xdemitconf_t const *xecfg, xdemitcb_t *xecb)
 120 {
 121         mmfile_t a = *mf1;
 122         mmfile_t b = *mf2;
 123
 124         if (mf1->size > MAX_XDIFF_SIZE || mf2->size > MAX_XDIFF_SIZE)
 125                 return -1;
 126
 127         if (!xecfg->ctxlen && !(xecfg->flags & XDL_EMIT_FUNCCONTEXT))
 128                 trim_common_tail(&a, &b);
 129
 130         return xdl_diff(&a, &b, xpp, xecfg, xecb);
 131 }
 132
 133 int xdi_diff_outf(mmfile_t *mf1, mmfile_t *mf2,
 134                   xdiff_emit_hunk_fn hunk_fn,
 135                   xdiff_emit_line_fn line_fn,
 136                   void *consume_callback_data,
 137                   xpparam_t const *xpp, xdemitconf_t const *xecfg)
 138 {
 139         int ret;
 140         struct xdiff_emit_state state;
 141         xdemitcb_t ecb;
 142
 143         memset(&state, 0, sizeof(state));
 144         state.hunk_fn = hunk_fn;
 145         state.line_fn = line_fn;
 146         state.consume_callback_data = consume_callback_data;
 147         memset(&ecb, 0, sizeof(ecb));
 148         if (hunk_fn)
 149                 ecb.out_hunk = xdiff_out_hunk;
 150         ecb.out_line = xdiff_outf;
 151         ecb.priv = &state;
 152         strbuf_init(&state.remainder, 0);
 153         ret = xdi_diff(mf1, mf2, xpp, xecfg, &ecb);
 154         strbuf_release(&state.remainder);
 155         return ret;
 156 }
 157
 158 int read_mmfile(mmfile_t *ptr, const char *filename)
 159 {
 160         struct stat st;
 161         FILE *f;
 162         size_t sz;
 163
 164         if (stat(filename, &st))
 165                 return error_errno("Could not stat %s", filename);
 166         if (!(f = fopen(filename, "rb")))
 167                 return error_errno("Could not open %s", filename);
 168         sz = xsize_t(st.st_size);
 169         ptr->ptr = xmalloc(sz ? sz : 1);
 170         if (sz && fread(ptr->ptr, sz, 1, f) != 1) {
 171                 fclose(f);
 172                 return error("Could not read %s", filename);
 173         }
 174         fclose(f);
 175         ptr->size = sz;
 176         return 0;
 177 }
 178
 179 void read_mmblob(mmfile_t *ptr, const struct object_id *oid)
 180 {
 181         unsigned long size;
 182         enum object_type type;
 183
 184         if (oideq(oid, null_oid(the_hash_algo))) {
 185                 ptr->ptr = xstrdup("");
 186                 ptr->size = 0;
 187                 return;
 188         }
 189
 190         ptr->ptr = odb_read_object(the_repository->objects, oid, &type, &size);
 191         if (!ptr->ptr || type != OBJ_BLOB)
 192                 die("unable to read blob object %s", oid_to_hex(oid));
 193         ptr->size = size;
 194 }
 195
 196 #define FIRST_FEW_BYTES 8000
 197 int buffer_is_binary(const char *ptr, unsigned long size)
 198 {
 199         if (FIRST_FEW_BYTES < size)
 200                 size = FIRST_FEW_BYTES;
 201         return !!memchr(ptr, 0, size);
 202 }
 203
 204 struct ff_regs {
 205         int nr;
 206         struct ff_reg {
 207                 regex_t re;
 208                 int negate;
 209         } *array;
 210 };
 211
 212 static long ff_regexp(const char *line, long len,
 213                 char *buffer, long buffer_size, void *priv)
 214 {
 215         struct ff_regs *regs = priv;
 216         regmatch_t pmatch[2];
 217         int i;
 218         int result;
 219
 220         /* Exclude terminating newline (and cr) from matching */
 221         if (len > 0 && line[len-1] == '\n') {
 222                 if (len > 1 && line[len-2] == '\r')
 223                         len -= 2;
 224                 else
 225                         len--;
 226         }
 227
 228         for (i = 0; i < regs->nr; i++) {
 229                 struct ff_reg *reg = regs->array + i;
 230                 if (!regexec_buf(&reg->re, line, len, 2, pmatch, 0)) {
 231                         if (reg->negate)
 232                                 return -1;
 233                         break;
 234                 }
 235         }
 236         if (regs->nr <= i)
 237                 return -1;
 238         i = pmatch[1].rm_so >= 0 ? 1 : 0;
 239         line += pmatch[i].rm_so;
 240         result = pmatch[i].rm_eo - pmatch[i].rm_so;
 241         if (result > buffer_size)
 242                 result = buffer_size;
 243         while (result > 0 && (isspace(line[result - 1])))
 244                 result--;
 245         memcpy(buffer, line, result);
 246         return result;
 247 }
 248
 249 void xdiff_set_find_func(xdemitconf_t *xecfg, const char *value, int cflags)
 250 {
 251         int i;
 252         struct ff_regs *regs;
 253
 254         xecfg->find_func = ff_regexp;
 255         regs = xecfg->find_func_priv = xmalloc(sizeof(struct ff_regs));
 256         for (i = 0, regs->nr = 1; value[i]; i++)
 257                 if (value[i] == '\n')
 258                         regs->nr++;
 259         ALLOC_ARRAY(regs->array, regs->nr);
 260         for (i = 0; i < regs->nr; i++) {
 261                 struct ff_reg *reg = regs->array + i;
 262                 const char *ep, *expression;
 263                 char *buffer = NULL;
 264
 265                 if (!value)
 266                         BUG("mismatch between line count and parsing");
 267                 ep = strchr(value, '\n');
 268
 269                 reg->negate = (*value == '!');
 270                 if (reg->negate && i == regs->nr - 1)
 271                         die("Last expression must not be negated: %s", value);
 272                 if (*value == '!')
 273                         value++;
 274                 if (ep)
 275                         expression = buffer = xstrndup(value, ep - value);
 276                 else
 277                         expression = value;
 278                 if (regcomp(&reg->re, expression, cflags))
 279                         die("Invalid regexp to look for hunk header: %s", expression);
 280                 free(buffer);
 281                 value = ep ? ep + 1 : NULL;
 282         }
 283 }
 284
 285 void xdiff_clear_find_func(xdemitconf_t *xecfg)
 286 {
 287         if (xecfg->find_func) {
 288                 int i;
 289                 struct ff_regs *regs = xecfg->find_func_priv;
 290
 291                 for (i = 0; i < regs->nr; i++)
 292                         regfree(&regs->array[i].re);
 293                 free(regs->array);
 294                 free(regs);
 295                 xecfg->find_func = NULL;
 296                 xecfg->find_func_priv = NULL;
 297         }
 298 }
 299
 300 unsigned long xdiff_hash_string(const char *s, size_t len, long flags)
 301 {
 302         return xdl_hash_record(&s, s + len, flags);
 303 }
 304
 305 int xdiff_compare_lines(const char *l1, long s1,
 306                         const char *l2, long s2, long flags)
 307 {
 308         return xdl_recmatch(l1, s1, l2, s2, flags);
 309 }
 310
 311 int parse_conflict_style_name(const char *value)
 312 {
 313         if (!strcmp(value, "diff3"))
 314                 return XDL_MERGE_DIFF3;
 315         else if (!strcmp(value, "zdiff3"))
 316                 return XDL_MERGE_ZEALOUS_DIFF3;
 317         else if (!strcmp(value, "merge"))
 318                 return 0;
 319         /*
 320          * Please update _git_checkout() in git-completion.bash when
 321          * you add new merge config
 322          */
 323         else
 324                 return -1;
 325 }
 326
 327 int git_xmerge_style = -1;
 328
 329 int git_xmerge_config(const char *var, const char *value,
 330                       const struct config_context *ctx, void *cb)
 331 {
 332         if (!strcmp(var, "merge.conflictstyle")) {
 333                 if (!value)
 334                         return config_error_nonbool(var);
 335                 git_xmerge_style = parse_conflict_style_name(value);
 336                 if (git_xmerge_style == -1)
 337                         return error(_("unknown style '%s' given for '%s'"),
 338                                      value, var);
 339                 return 0;
 340         }
 341         return git_default_config(var, value, ctx, cb);
 342 }