[PATCH v12 12/13] apply: learn to use a different index file

[Christian Couder <christian.couder@gmail.com>]

Sometimes we want to apply in a different index file.

Before the apply functionality was libified it was possible to
use the GIT_INDEX_FILE environment variable, for this purpose.

But now, as the apply functionality has been libified, it should
be possible to do that in a libified way.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
---
 apply.c | 10 ++++++++--
 apply.h |  1 +
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/apply.c b/apply.c
index 2ec2a8a..7e561a4 100644
--- a/apply.c
+++ b/apply.c
@@ -4674,8 +4674,14 @@ static int apply_patch(struct apply_state *state,
 		state->apply = 0;
 
 	state->update_index = state->check_index && state->apply;
-	if (state->update_index && state->newfd < 0)
-		state->newfd = hold_locked_index(state->lock_file, 1);
+	if (state->update_index && state->newfd < 0) {
+		if (state->index_file)
+			state->newfd = hold_lock_file_for_update(state->lock_file,
+								 state->index_file,
+								 LOCK_DIE_ON_ERROR);
+		else
+			state->newfd = hold_locked_index(state->lock_file, 1);
+	}
 
 	if (state->check_index && read_cache() < 0) {
 		error(_("unable to read index file"));
diff --git a/apply.h b/apply.h
index e2b89e8..1ba4f8d 100644
--- a/apply.h
+++ b/apply.h
@@ -63,6 +63,7 @@ struct apply_state {
 	int unsafe_paths;
 
 	/* Other non boolean parameters */
+	const char *index_file;
 	enum apply_verbosity apply_verbosity;
 	const char *fake_ancestor;
 	const char *patch_input_file;
-- 
2.9.2.769.gc0f0333