xdiff-interface.c

   1 #include "cache.h"
   2 #include "xdiff-interface.h"
   3
   4 static int parse_num(char **cp_p, int *num_p)
   5 {
   6         char *cp = *cp_p;
   7         int num = 0;
   8         int read_some;
   9
  10         while ('0' <= *cp && *cp <= '9')
  11                 num = num * 10 + *cp++ - '0';
  12         if (!(read_some = cp - *cp_p))
  13                 return -1;
  14         *cp_p = cp;
  15         *num_p = num;
  16         return 0;
  17 }
  18
  19 int parse_hunk_header(char *line, int len,
  20                       int *ob, int *on,
  21                       int *nb, int *nn)
  22 {
  23         char *cp;
  24         cp = line + 4;
  25         if (parse_num(&cp, ob)) {
  26         bad_line:
  27                 return error("malformed diff output: %s", line);
  28         }
  29         if (*cp == ',') {
  30                 cp++;
  31                 if (parse_num(&cp, on))
  32                         goto bad_line;
  33         }
  34         else
  35                 *on = 1;
  36         if (*cp++ != ' ' || *cp++ != '+')
  37                 goto bad_line;
  38         if (parse_num(&cp, nb))
  39                 goto bad_line;
  40         if (*cp == ',') {
  41                 cp++;
  42                 if (parse_num(&cp, nn))
  43                         goto bad_line;
  44         }
  45         else
  46                 *nn = 1;
  47         return -!!memcmp(cp, " @@", 3);
  48 }
  49
  50 static void consume_one(void *priv_, char *s, unsigned long size)
  51 {
  52         struct xdiff_emit_state *priv = priv_;
  53         char *ep;
  54         while (size) {
  55                 unsigned long this_size;
  56                 ep = memchr(s, '\n', size);
  57                 this_size = (ep == NULL) ? size : (ep - s + 1);
  58                 priv->consume(priv, s, this_size);
  59                 size -= this_size;
  60                 s += this_size;
  61         }
  62 }
  63
  64 static int xdiff_outf(void *priv_, mmbuffer_t *mb, int nbuf)
  65 {
  66         struct xdiff_emit_state *priv = priv_;
  67         int i;
  68
  69         for (i = 0; i < nbuf; i++) {
  70                 if (mb[i].ptr[mb[i].size-1] != '\n') {
  71                         /* Incomplete line */
  72                         strbuf_add(&priv->remainder, mb[i].ptr, mb[i].size);
  73                         continue;
  74                 }
  75
  76                 /* we have a complete line */
  77                 if (!priv->remainder.len) {
  78                         consume_one(priv, mb[i].ptr, mb[i].size);
  79                         continue;
  80                 }
  81                 strbuf_add(&priv->remainder, mb[i].ptr, mb[i].size);
  82                 consume_one(priv, priv->remainder.buf, priv->remainder.len);
  83                 strbuf_reset(&priv->remainder);
  84         }
  85         if (priv->remainder.len) {
  86                 consume_one(priv, priv->remainder.buf, priv->remainder.len);
  87                 strbuf_reset(&priv->remainder);
  88         }
  89         return 0;
  90 }
  91
  92 /*
  93  * Trim down common substring at the end of the buffers,
  94  * but leave at least ctx lines at the end.
  95  */
  96 static void trim_common_tail(mmfile_t *a, mmfile_t *b, long ctx)
  97 {
  98         const int blk = 1024;
  99         long trimmed = 0, recovered = 0;
 100         char *ap = a->ptr + a->size;
 101         char *bp = b->ptr + b->size;
 102         long smaller = (a->size < b->size) ? a->size : b->size;
 103
 104         if (ctx)
 105                 return;
 106
 107         while (blk + trimmed <= smaller && !memcmp(ap - blk, bp - blk, blk)) {
 108                 trimmed += blk;
 109                 ap -= blk;
 110                 bp -= blk;
 111         }
 112
 113         while (recovered < trimmed)
 114                 if (ap[recovered++] == '\n')
 115                         break;
 116         a->size -= trimmed - recovered;
 117         b->size -= trimmed - recovered;
 118 }
 119
 120 int xdi_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp, xdemitconf_t const *xecfg, xdemitcb_t *xecb)
 121 {
 122         mmfile_t a = *mf1;
 123         mmfile_t b = *mf2;
 124
 125         trim_common_tail(&a, &b, xecfg->ctxlen);
 126
 127         return xdl_diff(&a, &b, xpp, xecfg, xecb);
 128 }
 129
 130 int xdi_diff_outf(mmfile_t *mf1, mmfile_t *mf2,
 131                   struct xdiff_emit_state *state, xpparam_t const *xpp,
 132                   xdemitconf_t const *xecfg, xdemitcb_t *xecb)
 133 {
 134         int ret;
 135         xecb->outf = xdiff_outf;
 136         xecb->priv = state;
 137         strbuf_init(&state->remainder, 0);
 138         ret = xdi_diff(mf1, mf2, xpp, xecfg, xecb);
 139         strbuf_release(&state->remainder);
 140         return ret;
 141 }
 142
 143 int read_mmfile(mmfile_t *ptr, const char *filename)
 144 {
 145         struct stat st;
 146         FILE *f;
 147         size_t sz;
 148
 149         if (stat(filename, &st))
 150                 return error("Could not stat %s", filename);
 151         if ((f = fopen(filename, "rb")) == NULL)
 152                 return error("Could not open %s", filename);
 153         sz = xsize_t(st.st_size);
 154         ptr->ptr = xmalloc(sz ? sz : 1);
 155         if (sz && fread(ptr->ptr, sz, 1, f) != 1)
 156                 return error("Could not read %s", filename);
 157         fclose(f);
 158         ptr->size = sz;
 159         return 0;
 160 }
 161
 162 #define FIRST_FEW_BYTES 8000
 163 int buffer_is_binary(const char *ptr, unsigned long size)
 164 {
 165         if (FIRST_FEW_BYTES < size)
 166                 size = FIRST_FEW_BYTES;
 167         return !!memchr(ptr, 0, size);
 168 }
 169
 170 struct ff_regs {
 171         int nr;
 172         struct ff_reg {
 173                 regex_t re;
 174                 int negate;
 175         } *array;
 176 };
 177
 178 static long ff_regexp(const char *line, long len,
 179                 char *buffer, long buffer_size, void *priv)
 180 {
 181         char *line_buffer = xstrndup(line, len); /* make NUL terminated */
 182         struct ff_regs *regs = priv;
 183         regmatch_t pmatch[2];
 184         int result = 0, i;
 185
 186         for (i = 0; i < regs->nr; i++) {
 187                 struct ff_reg *reg = regs->array + i;
 188                 if (reg->negate ^ !!regexec(&reg->re,
 189                                         line_buffer, 2, pmatch, 0)) {
 190                         free(line_buffer);
 191                         return -1;
 192                 }
 193         }
 194         i = pmatch[1].rm_so >= 0 ? 1 : 0;
 195         line += pmatch[i].rm_so;
 196         result = pmatch[i].rm_eo - pmatch[i].rm_so;
 197         if (result > buffer_size)
 198                 result = buffer_size;
 199         else
 200                 while (result > 0 && (isspace(line[result - 1]) ||
 201                                         line[result - 1] == '\n'))
 202                         result--;
 203         memcpy(buffer, line, result);
 204         free(line_buffer);
 205         return result;
 206 }
 207
 208 void xdiff_set_find_func(xdemitconf_t *xecfg, const char *value)
 209 {
 210         int i;
 211         struct ff_regs *regs;
 212
 213         xecfg->find_func = ff_regexp;
 214         regs = xecfg->find_func_priv = xmalloc(sizeof(struct ff_regs));
 215         for (i = 0, regs->nr = 1; value[i]; i++)
 216                 if (value[i] == '\n')
 217                         regs->nr++;
 218         regs->array = xmalloc(regs->nr * sizeof(struct ff_reg));
 219         for (i = 0; i < regs->nr; i++) {
 220                 struct ff_reg *reg = regs->array + i;
 221                 const char *ep = strchr(value, '\n'), *expression;
 222                 char *buffer = NULL;
 223
 224                 reg->negate = (*value == '!');
 225                 if (reg->negate && i == regs->nr - 1)
 226                         die("Last expression must not be negated: %s", value);
 227                 if (*value == '!')
 228                         value++;
 229                 if (ep)
 230                         expression = buffer = xstrndup(value, ep - value);
 231                 else
 232                         expression = value;
 233                 if (regcomp(&reg->re, expression, 0))
 234                         die("Invalid regexp to look for hunk header: %s", expression);
 235                 free(buffer);
 236                 value = ep + 1;
 237         }
 238 }