1 files changed, 25 insertions, 16 deletions

diff --git a/xdiff-interface.c b/xdiff-interface.c
index 8509f9ea22..75b32aef51 100644
--- a/xdiff-interface.c
+++ b/xdiff-interface.c
@@ -31,29 +31,36 @@ static int xdiff_out_hunk(void *priv_,
 	return 0;
 }
 
-static void consume_one(void *priv_, char *s, unsigned long size)
+static int consume_one(void *priv_, char *s, unsigned long size)
 {
 	struct xdiff_emit_state *priv = priv_;
 	char *ep;
 	while (size) {
 		unsigned long this_size;
+		int ret;
 		ep = memchr(s, '\n', size);
 		this_size = (ep == NULL) ? size : (ep - s + 1);
-		priv->line_fn(priv->consume_callback_data, s, this_size);
+		ret = priv->line_fn(priv->consume_callback_data, s, this_size);
+		if (ret)
+			return ret;
 		size -= this_size;
 		s += this_size;
 	}
+	return 0;
 }
 
 static int xdiff_outf(void *priv_, mmbuffer_t *mb, int nbuf)
 {
 	struct xdiff_emit_state *priv = priv_;
 	int i;
+	int stop = 0;
 
 	if (!priv->line_fn)
 		return 0;
 
 	for (i = 0; i < nbuf; i++) {
+		if (stop)
+			return 1;
 		if (mb[i].ptr[mb[i].size-1] != '\n') {
 			/* Incomplete line */
 			strbuf_add(&priv->remainder, mb[i].ptr, mb[i].size);
@@ -62,17 +69,21 @@ static int xdiff_outf(void *priv_, mmbuffer_t *mb, int nbuf)
 
 		/* we have a complete line */
 		if (!priv->remainder.len) {
-			consume_one(priv, mb[i].ptr, mb[i].size);
+			stop = consume_one(priv, mb[i].ptr, mb[i].size);
 			continue;
 		}
 		strbuf_add(&priv->remainder, mb[i].ptr, mb[i].size);
-		consume_one(priv, priv->remainder.buf, priv->remainder.len);
+		stop = consume_one(priv, priv->remainder.buf, priv->remainder.len);
 		strbuf_reset(&priv->remainder);
 	}
+	if (stop)
+		return -1;
 	if (priv->remainder.len) {
-		consume_one(priv, priv->remainder.buf, priv->remainder.len);
+		stop = consume_one(priv, priv->remainder.buf, priv->remainder.len);
 		strbuf_reset(&priv->remainder);
 	}
+	if (stop)
+		return -1;
 	return 0;
 }
 
@@ -84,8 +95,8 @@ static void trim_common_tail(mmfile_t *a, mmfile_t *b)
 {
 	const int blk = 1024;
 	long trimmed = 0, recovered = 0;
-	char *ap = a->ptr + a->size;
-	char *bp = b->ptr + b->size;
+	char *ap = a->size ? a->ptr + a->size : a->ptr;
+	char *bp = b->size ? b->ptr + b->size : b->ptr;
 	long smaller = (a->size < b->size) ? a->size : b->size;
 
 	while (blk + trimmed <= smaller && !memcmp(ap - blk, bp - blk, blk)) {
@@ -115,12 +126,6 @@ int xdi_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp, xdemitconf_t co
 	return xdl_diff(&a, &b, xpp, xecfg, xecb);
 }
 
-void discard_hunk_line(void *priv,
-		       long ob, long on, long nb, long nn,
-		       const char *func, long funclen)
-{
-}
-
 int xdi_diff_outf(mmfile_t *mf1, mmfile_t *mf2,
 		  xdiff_emit_hunk_fn hunk_fn,
 		  xdiff_emit_line_fn line_fn,
@@ -172,7 +177,7 @@ void read_mmblob(mmfile_t *ptr, const struct object_id *oid)
 	unsigned long size;
 	enum object_type type;
 
-	if (oideq(oid, &null_oid)) {
+	if (oideq(oid, null_oid())) {
 		ptr->ptr = xstrdup("");
 		ptr->size = 0;
 		return;
@@ -250,9 +255,13 @@ void xdiff_set_find_func(xdemitconf_t *xecfg, const char *value, int cflags)
 	ALLOC_ARRAY(regs->array, regs->nr);
 	for (i = 0; i < regs->nr; i++) {
 		struct ff_reg *reg = regs->array + i;
-		const char *ep = strchr(value, '\n'), *expression;
+		const char *ep, *expression;
 		char *buffer = NULL;
 
+		if (!value)
+			BUG("mismatch between line count and parsing");
+		ep = strchr(value, '\n');
+
 		reg->negate = (*value == '!');
 		if (reg->negate && i == regs->nr - 1)
 			die("Last expression must not be negated: %s", value);
@@ -265,7 +274,7 @@ void xdiff_set_find_func(xdemitconf_t *xecfg, const char *value, int cflags)
 		if (regcomp(&reg->re, expression, cflags))
 			die("Invalid regexp to look for hunk header: %s", expression);
 		free(buffer);
-		value = ep + 1;
+		value = ep ? ep + 1 : NULL;
 	}
 }