Make on-disk index representation separate from in-core one

diff --git a/xdiff-interface.c b/xdiff-interface.c
index e407cf11b1d8ba28be64eda7bcb505d9edb4d253..4b8e5cca804198b0e227454a585fa025281bbe2d 100644 (file)
--- a/xdiff-interface.c
+++ b/xdiff-interface.c
@@ -103,6 +103,44 @@ int xdiff_outf(void *priv_, mmbuffer_t *mb, int nbuf)
        return 0;
 }
 
+/*
+ * Trim down common substring at the end of the buffers,
+ * but leave at least ctx lines at the end.
+ */
+static void trim_common_tail(mmfile_t *a, mmfile_t *b, long ctx)
+{
+       const int blk = 1024;
+       long trimmed = 0, recovered = 0;
+       char *ap = a->ptr + a->size;
+       char *bp = b->ptr + b->size;
+       long smaller = (a->size < b->size) ? a->size : b->size;
+
+       if (ctx)
+               return;
+
+       while (blk + trimmed <= smaller && !memcmp(ap - blk, bp - blk, blk)) {
+               trimmed += blk;
+               ap -= blk;
+               bp -= blk;
+       }
+
+       while (recovered < trimmed)
+               if (ap[recovered++] == '\n')
+                       break;
+       a->size -= trimmed - recovered;
+       b->size -= trimmed - recovered;
+}
+
+int xdi_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp, xdemitconf_t const *xecfg, xdemitcb_t *xecb)
+{
+       mmfile_t a = *mf1;
+       mmfile_t b = *mf2;
+
+       trim_common_tail(&a, &b, xecfg->ctxlen);
+
+       return xdl_diff(&a, &b, xpp, xecfg, xecb);
+}
+
 int read_mmfile(mmfile_t *ptr, const char *filename)
 {
        struct stat st;
@@ -129,3 +167,74 @@ int buffer_is_binary(const char *ptr, unsigned long size)
                size = FIRST_FEW_BYTES;
        return !!memchr(ptr, 0, size);
 }
+
+struct ff_regs {
+       int nr;
+       struct ff_reg {
+               regex_t re;
+               int negate;
+       } *array;
+};
+
+static long ff_regexp(const char *line, long len,
+               char *buffer, long buffer_size, void *priv)
+{
+       char *line_buffer = xstrndup(line, len); /* make NUL terminated */
+       struct ff_regs *regs = priv;
+       regmatch_t pmatch[2];
+       int result = 0, i;
+
+       for (i = 0; i < regs->nr; i++) {
+               struct ff_reg *reg = regs->array + i;
+               if (reg->negate ^ !!regexec(&reg->re,
+                                       line_buffer, 2, pmatch, 0)) {
+                       free(line_buffer);
+                       return -1;
+               }
+       }
+       i = pmatch[1].rm_so >= 0 ? 1 : 0;
+       line += pmatch[i].rm_so;
+       result = pmatch[i].rm_eo - pmatch[i].rm_so;
+       if (result > buffer_size)
+               result = buffer_size;
+       else
+               while (result > 0 && (isspace(line[result - 1]) ||
+                                       line[result - 1] == '\n'))
+                       result--;
+       memcpy(buffer, line, result);
+       free(line_buffer);
+       return result;
+}
+
+void xdiff_set_find_func(xdemitconf_t *xecfg, const char *value)
+{
+       int i;
+       struct ff_regs *regs;
+
+       xecfg->find_func = ff_regexp;
+       regs = xecfg->find_func_priv = xmalloc(sizeof(struct ff_regs));
+       for (i = 0, regs->nr = 1; value[i]; i++)
+               if (value[i] == '\n')
+                       regs->nr++;
+       regs->array = xmalloc(regs->nr * sizeof(struct ff_reg));
+       for (i = 0; i < regs->nr; i++) {
+               struct ff_reg *reg = regs->array + i;
+               const char *ep = strchr(value, '\n'), *expression;
+               char *buffer = NULL;
+
+               reg->negate = (*value == '!');
+               if (reg->negate && i == regs->nr - 1)
+                       die("Last expression must not be negated: %s", value);
+               if (*value == '!')
+                       value++;
+               if (ep)
+                       expression = buffer = xstrndup(value, ep - value);
+               else
+                       expression = value;
+               if (regcomp(&reg->re, expression, 0))
+                       die("Invalid regexp to look for hunk header: %s", expression);
+               if (buffer)
+                       free(buffer);
+               value = ep + 1;
+       }
+}