[PATCH 6/9] combine-diff: use an xdiff hunk callback

[Jeff King <peff@peff.net>]

A combined diff has to line up the hunks for all of the individual
pairwise diffs, and thus needs to know their line numbers and sizes. We
get that now by parsing the hunk header line that xdiff generates.
However, now that xdiff supports a hunk callback, we can just use the
values directly.

Signed-off-by: Jeff King <peff@peff.net>
---
I learned to love --color-moved-ws=allow-indentation-change for this
one.

 combine-diff.c | 67 +++++++++++++++++++++++++++-----------------------
 1 file changed, 36 insertions(+), 31 deletions(-)

diff --git a/combine-diff.c b/combine-diff.c
index 3c479cfc3e..ad7752ea6b 100644
--- a/combine-diff.c
+++ b/combine-diff.c
@@ -345,38 +345,43 @@ struct combine_diff_state {
 	struct sline *lost_bucket;
 };
 
-static void consume_line(void *state_, char *line, unsigned long len)
+static void consume_hunk(void *state_,
+			 long ob, long on,
+			 long nb, long nn,
+			 const char *funcline, long funclen)
 {
 	struct combine_diff_state *state = state_;
-	if (5 < len && !memcmp("@@ -", line, 4)) {
-		if (parse_hunk_header(line, len,
-				      &state->ob, &state->on,
-				      &state->nb, &state->nn))
-			return;
-		state->lno = state->nb;
-		if (state->nn == 0) {
-			/* @@ -X,Y +N,0 @@ removed Y lines
-			 * that would have come *after* line N
-			 * in the result.  Our lost buckets hang
-			 * to the line after the removed lines,
-			 *
-			 * Note that this is correct even when N == 0,
-			 * in which case the hunk removes the first
-			 * line in the file.
-			 */
-			state->lost_bucket = &state->sline[state->nb];
-			if (!state->nb)
-				state->nb = 1;
-		} else {
-			state->lost_bucket = &state->sline[state->nb-1];
-		}
-		if (!state->sline[state->nb-1].p_lno)
-			state->sline[state->nb-1].p_lno =
-				xcalloc(state->num_parent,
-					sizeof(unsigned long));
-		state->sline[state->nb-1].p_lno[state->n] = state->ob;
-		return;
+
+	state->ob = ob;
+	state->on = on;
+	state->nb = nb;
+	state->nn = nn;
+	state->lno = state->nb;
+	if (state->nn == 0) {
+		/* @@ -X,Y +N,0 @@ removed Y lines
+		 * that would have come *after* line N
+		 * in the result.  Our lost buckets hang
+		 * to the line after the removed lines,
+		 *
+		 * Note that this is correct even when N == 0,
+		 * in which case the hunk removes the first
+		 * line in the file.
+		 */
+		state->lost_bucket = &state->sline[state->nb];
+		if (!state->nb)
+			state->nb = 1;
+	} else {
+		state->lost_bucket = &state->sline[state->nb-1];
 	}
+	if (!state->sline[state->nb-1].p_lno)
+		state->sline[state->nb-1].p_lno =
+			xcalloc(state->num_parent, sizeof(unsigned long));
+	state->sline[state->nb-1].p_lno[state->n] = state->ob;
+}
+
+static void consume_line(void *state_, char *line, unsigned long len)
+{
+	struct combine_diff_state *state = state_;
 	if (!state->lost_bucket)
 		return; /* not in any hunk yet */
 	switch (line[0]) {
@@ -421,8 +426,8 @@ static void combine_diff(struct repository *r,
 	state.num_parent = num_parent;
 	state.n = n;
 
-	if (xdi_diff_outf(&parent_file, result_file, NULL, consume_line,
-			  &state, &xpp, &xecfg))
+	if (xdi_diff_outf(&parent_file, result_file, consume_hunk,
+			  consume_line, &state, &xpp, &xecfg))
 		die("unable to generate combined diff for %s",
 		    oid_to_hex(parent));
 	free(parent_file.ptr);
-- 
2.19.1.1336.g081079ac04