Merge branch 'lt/merge-tree'

* lt/merge-tree:
  Improved three-way blob merging code
  Prepare "git-merge-tree" for future work
  xdiff: generate "anti-diffs" aka what is common to two files

2 files changed, 19 insertions, 0 deletions

diff --git a/xdiff/xdiff.h b/xdiff/xdiff.h
index 2ce10b4c0..c9f817818 100644
--- a/xdiff/xdiff.h
+++ b/xdiff/xdiff.h
@@ -39,6 +39,7 @@ extern "C" {
 #define XDL_PATCH_IGNOREBSPACE (1 << 8)
 
 #define XDL_EMIT_FUNCNAMES (1 << 0)
+#define XDL_EMIT_COMMON (1 << 1)
 
 #define XDL_MMB_READONLY (1 << 0)
 
diff --git a/xdiff/xemit.c b/xdiff/xemit.c
index ad5bfb191..714c56354 100644
--- a/xdiff/xemit.c
+++ b/xdiff/xemit.c
@@ -100,6 +100,21 @@ static void xdl_find_func(xdfile_t *xf, long i, char *buf, long sz, long *ll) {
 }
 
 
+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;
@@ -107,6 +122,9 @@ int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
 	char funcbuf[40];
 	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);