builtin-prune: memory diet.

diff --git a/xdiff/xemit.c b/xdiff/xemit.c
index 2e5d54cfcf6dae715e500df26d1b6dab418fdefc..e291dc7608c4ab9b54a5d049bf3b555704e37fe8 100644 (file)
--- a/xdiff/xemit.c
+++ b/xdiff/xemit.c
@@ -69,10 +69,60 @@ static xdchange_t *xdl_get_hunk(xdchange_t *xscr, xdemitconf_t const *xecfg) {
 }
 
 
+static void xdl_find_func(xdfile_t *xf, long i, char *buf, long sz, long *ll) {
+
+       /*
+        * Be quite stupid about this for now.  Find a line in the old file
+        * before the start of the hunk (and context) which starts with a
+        * plausible character.
+        */
+
+       const char *rec;
+       long len;
+
+       *ll = 0;
+       while (i-- > 0) {
+               len = xdl_get_rec(xf, i, &rec);
+               if (len > 0 &&
+                   (isalpha((unsigned char)*rec) || /* identifier? */
+                    *rec == '_' ||     /* also identifier? */
+                    *rec == '$')) {    /* mysterious GNU diff's invention */
+                       if (len > sz)
+                               len = sz;
+                       while (0 < len && isspace((unsigned char)rec[len - 1]))
+                               len--;
+                       memcpy(buf, rec, len);
+                       *ll = len;
+                       return;
+               }
+       }
+}
+
+
+int xdl_emit_common(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
+                   xdemitconf_t const *xecfg) {
+       xdfile_t *xdf = &xe->xdf1;
+       const char *rchg = xdf->rchg;
+       long ix;
+
+       for (ix = 0; ix < xdf->nrec; ix++) {
+               if (rchg[ix])
+                       continue;
+               if (xdl_emit_record(xdf, ix, "", ecb))
+                       return -1;
+       }
+       return 0;
+}
+
 int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
                  xdemitconf_t const *xecfg) {
        long s1, s2, e1, e2, lctx;
        xdchange_t *xch, *xche;
+       char funcbuf[80];
+       long funclen = 0;
+
+       if (xecfg->flags & XDL_EMIT_COMMON)
+               return xdl_emit_common(xe, xscr, ecb, xecfg);
 
        for (xch = xche = xscr; xch; xch = xche->next) {
                xche = xdl_get_hunk(xch, xecfg);
@@ -90,7 +140,13 @@ int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
                /*
                 * Emit current hunk header.
                 */
-               if (xdl_emit_hunk_hdr(s1 + 1, e1 - s1, s2 + 1, e2 - s2, ecb) < 0)
+
+               if (xecfg->flags & XDL_EMIT_FUNCNAMES) {
+                       xdl_find_func(&xe->xdf1, s1, funcbuf,
+                                     sizeof(funcbuf), &funclen);
+               }
+               if (xdl_emit_hunk_hdr(s1 + 1, e1 - s1, s2 + 1, e2 - s2,
+                                     funcbuf, funclen, ecb) < 0)
                        return -1;
 
                /*