xdiff-interface.c

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