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