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