[PATCH 3/4] cache.h: replace 'index_entry_exists()' with 'index_name_pos_sparse()'

["Victoria Dye via GitGitGadget" <gitgitgadget@gmail.com>]

From: Victoria Dye <vdye@github.com>

Replace 'index_entry_exists()' (which returns a binary '1' or '0' depending
on whether a specified entry exists in the index) with
'index_name_pos_sparse()' (which behaves the same as 'index_name_pos()',
except that it does not expand a sparse index to search for an entry inside
a sparse directory).

'index_entry_exists()' was original implemented in 20ec2d034c (reset: make
sparse-aware (except --mixed), 2021-11-29) to allow callers to search for an
index entry without expanding a sparse index. That particular case only
required knowing whether the requested entry existed. This patch expands the
amount of information returned by indicating both 1) whether the entry
exists, and 2) its position (or potential position) in the index.

Signed-off-by: Victoria Dye <vdye@github.com>
---
 cache-tree.c |  2 +-
 cache.h      | 15 +++++++--------
 read-cache.c |  4 ++--
 3 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/cache-tree.c b/cache-tree.c
index 56db0b5026b..ff0c1733356 100644
--- a/cache-tree.c
+++ b/cache-tree.c
@@ -798,7 +798,7 @@ static void prime_cache_tree_rec(struct repository *r,
 			 * as normal.
 			 */
 			if (r->index->sparse_index &&
-			    index_entry_exists(r->index, tree_path->buf, tree_path->len))
+			    index_name_pos_sparse(r->index, tree_path->buf, tree_path->len) >= 0)
 				prime_cache_tree_sparse_dir(sub->cache_tree, subtree);
 			else
 				prime_cache_tree_rec(r, sub->cache_tree, subtree, tree_path);
diff --git a/cache.h b/cache.h
index 4aa1bd079d5..6bfd1d80b24 100644
--- a/cache.h
+++ b/cache.h
@@ -831,14 +831,13 @@ struct cache_entry *index_file_exists(struct index_state *istate, const char *na
 int index_name_pos(struct index_state *, const char *name, int namelen);
 
 /*
- * Determines whether an entry with the given name exists within the
- * given index. The return value is 1 if an exact match is found, otherwise
- * it is 0. Note that, unlike index_name_pos, this function does not expand
- * the index if it is sparse. If an item exists within the full index but it
- * is contained within a sparse directory (and not in the sparse index), 0 is
- * returned.
- */
-int index_entry_exists(struct index_state *, const char *name, int namelen);
+ * Like index_name_pos, returns the position of an entry of the given name in
+ * the index if one exists, otherwise returns a negative value where the negated
+ * value minus 1 is the position where the index entry would be inserted. Unlike
+ * index_name_pos, however, a sparse index is not expanded to find an entry
+ * inside a sparse directory.
+ */
+int index_name_pos_sparse(struct index_state *, const char *name, int namelen);
 
 /*
  * Some functions return the negative complement of an insert position when a
diff --git a/read-cache.c b/read-cache.c
index 4de207752dc..a85b922a3bc 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -620,9 +620,9 @@ int index_name_pos(struct index_state *istate, const char *name, int namelen)
 	return index_name_stage_pos(istate, name, namelen, 0, EXPAND_SPARSE);
 }
 
-int index_entry_exists(struct index_state *istate, const char *name, int namelen)
+int index_name_pos_sparse(struct index_state *istate, const char *name, int namelen)
 {
-	return index_name_stage_pos(istate, name, namelen, 0, NO_EXPAND_SPARSE) >= 0;
+	return index_name_stage_pos(istate, name, namelen, 0, NO_EXPAND_SPARSE);
 }
 
 int remove_index_entry_at(struct index_state *istate, int pos)
-- 
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