xdiff-interface.c

   1 #include "cache.h"
   2 #include "xdiff-interface.h"
   3 #include "strbuf.h"
   4
   5 struct xdiff_emit_state {
   6         xdiff_emit_consume_fn consume;
   7         void *consume_callback_data;
   8         struct strbuf remainder;
   9 };
  10
  11 static int parse_num(char **cp_p, int *num_p)
  12 {
  13         char *cp = *cp_p;
  14         int num = 0;
  15         int read_some;
  16
  17         while ('0' <= *cp && *cp <= '9')
  18                 num = num * 10 + *cp++ - '0';
  19         if (!(read_some = cp - *cp_p))
  20                 return -1;
  21         *cp_p = cp;
  22         *num_p = num;
  23         return 0;
  24 }
  25
  26 int parse_hunk_header(char *line, int len,
  27                       int *ob, int *on,
  28                       int *nb, int *nn)
  29 {
  30         char *cp;
  31         cp = line + 4;
  32         if (parse_num(&cp, ob)) {
  33         bad_line:
  34                 return error("malformed diff output: %s", line);
  35         }
  36         if (*cp == ',') {
  37                 cp++;
  38                 if (parse_num(&cp, on))
  39                         goto bad_line;
  40         }
  41         else
  42                 *on = 1;
  43         if (*cp++ != ' ' || *cp++ != '+')
  44                 goto bad_line;
  45         if (parse_num(&cp, nb))
  46                 goto bad_line;
  47         if (*cp == ',') {
  48                 cp++;
  49                 if (parse_num(&cp, nn))
  50                         goto bad_line;
  51         }
  52         else
  53                 *nn = 1;
  54         return -!!memcmp(cp, " @@", 3);
  55 }
  56
  57 static void consume_one(void *priv_, char *s, unsigned long size)
  58 {
  59         struct xdiff_emit_state *priv = priv_;
  60         char *ep;
  61         while (size) {
  62                 unsigned long this_size;
  63                 ep = memchr(s, '\n', size);
  64                 this_size = (ep == NULL) ? size : (ep - s + 1);
  65                 priv->consume(priv->consume_callback_data, s, this_size);
  66                 size -= this_size;
  67                 s += this_size;
  68         }
  69 }
  70
  71 static int xdiff_outf(void *priv_, mmbuffer_t *mb, int nbuf)
  72 {
  73         struct xdiff_emit_state *priv = priv_;
  74         int i;
  75
  76         for (i = 0; i < nbuf; i++) {
  77                 if (mb[i].ptr[mb[i].size-1] != '\n') {
  78                         /* Incomplete line */
  79                         strbuf_add(&priv->remainder, mb[i].ptr, mb[i].size);
  80                         continue;
  81                 }
  82
  83                 /* we have a complete line */
  84                 if (!priv->remainder.len) {
  85                         consume_one(priv, mb[i].ptr, mb[i].size);
  86                         continue;
  87                 }
  88                 strbuf_add(&priv->remainder, mb[i].ptr, mb[i].size);
  89                 consume_one(priv, priv->remainder.buf, priv->remainder.len);
  90                 strbuf_reset(&priv->remainder);
  91         }
  92         if (priv->remainder.len) {
  93                 consume_one(priv, priv->remainder.buf, priv->remainder.len);
  94                 strbuf_reset(&priv->remainder);
  95         }
  96         return 0;
  97 }
  98
  99 /*
 100  * Trim down common substring at the end of the buffers,
 101  * but leave at least ctx lines at the end.
 102  */
 103 static void trim_common_tail(mmfile_t *a, mmfile_t *b, long ctx)
 104 {
 105         const int blk = 1024;
 106         long trimmed = 0, recovered = 0;
 107         char *ap = a->ptr + a->size;
 108         char *bp = b->ptr + b->size;
 109         long smaller = (a->size < b->size) ? a->size : b->size;
 110
 111         if (ctx)
 112                 return;
 113
 114         while (blk + trimmed <= smaller && !memcmp(ap - blk, bp - blk, blk)) {
 115                 trimmed += blk;
 116                 ap -= blk;
 117                 bp -= blk;
 118         }
 119
 120         while (recovered < trimmed)
 121                 if (ap[recovered++] == '\n')
 122                         break;
 123         a->size -= trimmed - recovered;
 124         b->size -= trimmed - recovered;
 125 }
 126
 127 int xdi_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp, xdemitconf_t const *xecfg, xdemitcb_t *xecb)
 128 {
 129         mmfile_t a = *mf1;
 130         mmfile_t b = *mf2;
 131
 132         trim_common_tail(&a, &b, xecfg->ctxlen);
 133
 134         return xdl_diff(&a, &b, xpp, xecfg, xecb);
 135 }
 136
 137 int xdi_diff_outf(mmfile_t *mf1, mmfile_t *mf2,
 138                   xdiff_emit_consume_fn fn, void *consume_callback_data,
 139                   xpparam_t const *xpp,
 140                   xdemitconf_t const *xecfg, xdemitcb_t *xecb)
 141 {
 142         int ret;
 143         struct xdiff_emit_state state;
 144
 145         memset(&state, 0, sizeof(state));
 146         state.consume = fn;
 147         state.consume_callback_data = consume_callback_data;
 148         xecb->outf = xdiff_outf;
 149         xecb->priv = &state;
 150         strbuf_init(&state.remainder, 0);
 151         ret = xdi_diff(mf1, mf2, xpp, xecfg, xecb);
 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("Could not stat %s", filename);
 164         if ((f = fopen(filename, "rb")) == NULL)
 165                 return error("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                 return error("Could not read %s", filename);
 170         fclose(f);
 171         ptr->size = sz;
 172         return 0;
 173 }
 174
 175 #define FIRST_FEW_BYTES 8000
 176 int buffer_is_binary(const char *ptr, unsigned long size)
 177 {
 178         if (FIRST_FEW_BYTES < size)
 179                 size = FIRST_FEW_BYTES;
 180         return !!memchr(ptr, 0, size);
 181 }
 182
 183 struct ff_regs {
 184         int nr;
 185         struct ff_reg {
 186                 regex_t re;
 187                 int negate;
 188         } *array;
 189 };
 190
 191 static long ff_regexp(const char *line, long len,
 192                 char *buffer, long buffer_size, void *priv)
 193 {
 194         char *line_buffer = xstrndup(line, len); /* make NUL terminated */
 195         struct ff_regs *regs = priv;
 196         regmatch_t pmatch[2];
 197         int result = 0, i;
 198
 199         for (i = 0; i < regs->nr; i++) {
 200                 struct ff_reg *reg = regs->array + i;
 201                 if (reg->negate ^ !!regexec(&reg->re,
 202                                         line_buffer, 2, pmatch, 0)) {
 203                         free(line_buffer);
 204                         return -1;
 205                 }
 206         }
 207         i = pmatch[1].rm_so >= 0 ? 1 : 0;
 208         line += pmatch[i].rm_so;
 209         result = pmatch[i].rm_eo - pmatch[i].rm_so;
 210         if (result > buffer_size)
 211                 result = buffer_size;
 212         else
 213                 while (result > 0 && (isspace(line[result - 1]) ||
 214                                         line[result - 1] == '\n'))
 215                         result--;
 216         memcpy(buffer, line, result);
 217         free(line_buffer);
 218         return result;
 219 }
 220
 221 void xdiff_set_find_func(xdemitconf_t *xecfg, const char *value)
 222 {
 223         int i;
 224         struct ff_regs *regs;
 225
 226         xecfg->find_func = ff_regexp;
 227         regs = xecfg->find_func_priv = xmalloc(sizeof(struct ff_regs));
 228         for (i = 0, regs->nr = 1; value[i]; i++)
 229                 if (value[i] == '\n')
 230                         regs->nr++;
 231         regs->array = xmalloc(regs->nr * sizeof(struct ff_reg));
 232         for (i = 0; i < regs->nr; i++) {
 233                 struct ff_reg *reg = regs->array + i;
 234                 const char *ep = strchr(value, '\n'), *expression;
 235                 char *buffer = NULL;
 236
 237                 reg->negate = (*value == '!');
 238                 if (reg->negate && i == regs->nr - 1)
 239                         die("Last expression must not be negated: %s", value);
 240                 if (*value == '!')
 241                         value++;
 242                 if (ep)
 243                         expression = buffer = xstrndup(value, ep - value);
 244                 else
 245                         expression = value;
 246                 if (regcomp(&reg->re, expression, 0))
 247                         die("Invalid regexp to look for hunk header: %s", expression);
 248                 free(buffer);
 249                 value = ep + 1;
 250         }
 251 }