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