read-cache: introduce chmod_index_entry

As there are chmod options for both add and update-index, introduce a
new chmod_index_entry function to do the work.  Use it in update-index,
while it will be used in add in the next patch.

Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 29 insertions, 0 deletions

diff --git a/read-cache.c b/read-cache.c
index db27766..d11a43b 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -759,6 +759,35 @@ struct cache_entry *make_cache_entry(unsigned int mode,
 	return ret;
 }
 
+/*
+ * Chmod an index entry with either +x or -x.
+ *
+ * Returns -1 if the chmod for the particular cache entry failed (if it's
+ * not a regular file), -2 if an invalid flip argument is passed in, 0
+ * otherwise.
+ */
+int chmod_index_entry(struct index_state *istate, struct cache_entry *ce,
+		      char flip)
+{
+	if (!S_ISREG(ce->ce_mode))
+		return -1;
+	switch (flip) {
+	case '+':
+		ce->ce_mode |= 0111;
+		break;
+	case '-':
+		ce->ce_mode &= ~0111;
+		break;
+	default:
+		return -2;
+	}
+	cache_tree_invalidate_path(istate, ce->name);
+	ce->ce_flags |= CE_UPDATE_IN_BASE;
+	istate->cache_changed |= CE_ENTRY_CHANGED;
+
+	return 0;
+}
+
 int ce_same_name(const struct cache_entry *a, const struct cache_entry *b)
 {
 	int len = ce_namelen(a);