[PATCH v8 06/14] update-index: move add_cacheinfo() to read-cache.c

[Alban Gruin <alban.gruin@gmail.com>]

This moves the function add_cacheinfo() that already exists in
update-index.c to update-index.c, renames it add_to_index_cacheinfo(),
and adds an `istate' parameter.  The new cache entry is returned through
a pointer passed in the parameters.  This function can return three
values:

 - 0, when the file has been successfully added to the index;
 - ADD_TO_INDEX_CACHEINFO_INVALID_PATH, when the file does not exists;
 - ADD_TO_INDEX_CACHEINFO_UNABLE_TO_ADD, when the file could not be
   added to the index.

This will become useful in the next commit, when the three-way merge
will need to call this function.

Signed-off-by: Alban Gruin <alban.gruin@gmail.com>
---
 builtin/update-index.c | 25 +++++++------------------
 cache.h                |  8 ++++++++
 read-cache.c           | 35 +++++++++++++++++++++++++++++++++++
 3 files changed, 50 insertions(+), 18 deletions(-)

diff --git a/builtin/update-index.c b/builtin/update-index.c
index b62249905f..2e322a58f2 100644
--- a/builtin/update-index.c
+++ b/builtin/update-index.c
@@ -411,27 +411,16 @@ static int process_path(const char *path, struct stat *st, int stat_errno)
 static int add_cacheinfo(unsigned int mode, const struct object_id *oid,
 			 const char *path, int stage)
 {
-	int len, option;
-	struct cache_entry *ce;
+	int res;
 
-	if (!verify_path(path, mode))
-		return error("Invalid path '%s'", path);
-
-	len = strlen(path);
-	ce = make_empty_cache_entry(&the_index, len);
-
-	oidcpy(&ce->oid, oid);
-	memcpy(ce->name, path, len);
-	ce->ce_flags = create_ce_flags(stage);
-	ce->ce_namelen = len;
-	ce->ce_mode = create_ce_mode(mode);
-	if (assume_unchanged)
-		ce->ce_flags |= CE_VALID;
-	option = allow_add ? ADD_CACHE_OK_TO_ADD : 0;
-	option |= allow_replace ? ADD_CACHE_OK_TO_REPLACE : 0;
-	if (add_cache_entry(ce, option))
+	res = add_to_index_cacheinfo(&the_index, mode, oid, path, stage,
+				     allow_add, allow_replace, NULL);
+	if (res == ADD_TO_INDEX_CACHEINFO_INVALID_PATH)
+		return error(_("Invalid path '%s'"), path);
+	if (res == ADD_TO_INDEX_CACHEINFO_UNABLE_TO_ADD)
 		return error("%s: cannot add to the index - missing --add option?",
 			     path);
+
 	report("add '%s'", path);
 	return 0;
 }
diff --git a/cache.h b/cache.h
index 4aa1bd079d..6b5d0a2ba3 100644
--- a/cache.h
+++ b/cache.h
@@ -885,6 +885,14 @@ int remove_file_from_index(struct index_state *, const char *path);
 int add_to_index(struct index_state *, const char *path, struct stat *, int flags);
 int add_file_to_index(struct index_state *, const char *path, int flags);
 
+#define ADD_TO_INDEX_CACHEINFO_INVALID_PATH (-1)
+#define ADD_TO_INDEX_CACHEINFO_UNABLE_TO_ADD (-2)
+
+int add_to_index_cacheinfo(struct index_state *, unsigned int mode,
+			   const struct object_id *oid, const char *path,
+			   int stage, int allow_add, int allow_replace,
+			   struct cache_entry **ce_ret);
+
 int chmod_index_entry(struct index_state *, struct cache_entry *ce, char flip);
 int ce_same_name(const struct cache_entry *a, const struct cache_entry *b);
 void set_object_name_for_intent_to_add_entry(struct cache_entry *ce);
diff --git a/read-cache.c b/read-cache.c
index 4de207752d..e895bf5c6a 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -1436,6 +1436,41 @@ int add_index_entry(struct index_state *istate, struct cache_entry *ce, int opti
 	return 0;
 }
 
+int add_to_index_cacheinfo(struct index_state *istate, unsigned int mode,
+			   const struct object_id *oid, const char *path,
+			   int stage, int allow_add, int allow_replace,
+			   struct cache_entry **ce_ret)
+{
+	int len, option;
+	struct cache_entry *ce;
+
+	if (!verify_path(path, mode))
+		return ADD_TO_INDEX_CACHEINFO_INVALID_PATH;
+
+	len = strlen(path);
+	ce = make_empty_cache_entry(istate, len);
+
+	oidcpy(&ce->oid, oid);
+	memcpy(ce->name, path, len);
+	ce->ce_flags = create_ce_flags(stage);
+	ce->ce_namelen = len;
+	ce->ce_mode = create_ce_mode(mode);
+	if (assume_unchanged)
+		ce->ce_flags |= CE_VALID;
+	option = allow_add ? ADD_CACHE_OK_TO_ADD : 0;
+	option |= allow_replace ? ADD_CACHE_OK_TO_REPLACE : 0;
+
+	if (add_index_entry(istate, ce, option)) {
+		discard_cache_entry(ce);
+		return ADD_TO_INDEX_CACHEINFO_UNABLE_TO_ADD;
+	}
+
+	if (ce_ret)
+		*ce_ret = ce;
+
+	return 0;
+}
+
 /*
  * "refresh" does not calculate a new sha1 file or bring the
  * cache up-to-date for mode/content changes. But what it
-- 
2.37.1.412.gcfdce49ffd