[PATCH v4 11/24] read-cache: make in-memory format aware of stat_crc

[Thomas Gummerer <t.gummerer@gmail.com>]

Make the in-memory format aware of the stat_crc used by index-v5.
It is simply ignored by index version prior to v5.

Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com>
---
 cache.h      |  1 +
 read-cache.c | 25 +++++++++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/cache.h b/cache.h
index 38d57e7..8c2ccc4 100644
--- a/cache.h
+++ b/cache.h
@@ -127,6 +127,7 @@ struct cache_entry {
 	unsigned int ce_flags;
 	unsigned int ce_namelen;
 	unsigned char sha1[20];
+	uint32_t ce_stat_crc;
 	struct cache_entry *next; /* used by name_hash */
 	char name[FLEX_ARRAY]; /* more */
 };
diff --git a/read-cache.c b/read-cache.c
index 7020f26..baa052c 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -106,6 +106,29 @@ int match_stat_data(const struct stat_data *sd, struct stat *st)
 	return changed;
 }
 
+static uint32_t calculate_stat_crc(struct cache_entry *ce)
+{
+	unsigned int ctimens = 0;
+	uint32_t stat, stat_crc;
+
+	stat = htonl(ce->ce_stat_data.sd_ctime.sec);
+	stat_crc = crc32(0, (Bytef*)&stat, 4);
+#ifdef USE_NSEC
+	ctimens = ce->ce_stat_data.sd_ctime.nsec;
+#endif
+	stat = htonl(ctimens);
+	stat_crc = crc32(stat_crc, (Bytef*)&stat, 4);
+	stat = htonl(ce->ce_stat_data.sd_ino);
+	stat_crc = crc32(stat_crc, (Bytef*)&stat, 4);
+	stat = htonl(ce->ce_stat_data.sd_dev);
+	stat_crc = crc32(stat_crc, (Bytef*)&stat, 4);
+	stat = htonl(ce->ce_stat_data.sd_uid);
+	stat_crc = crc32(stat_crc, (Bytef*)&stat, 4);
+	stat = htonl(ce->ce_stat_data.sd_gid);
+	stat_crc = crc32(stat_crc, (Bytef*)&stat, 4);
+	return stat_crc;
+}
+
 /*
  * This only updates the "non-critical" parts of the directory
  * cache, ie the parts that aren't tracked by GIT, and only used
@@ -120,6 +143,8 @@ void fill_stat_cache_info(struct cache_entry *ce, struct stat *st)
 
 	if (S_ISREG(st->st_mode))
 		ce_mark_uptodate(ce);
+
+	ce->ce_stat_crc = calculate_stat_crc(ce);
 }
 
 static int ce_compare_data(const struct cache_entry *ce, struct stat *st)
-- 
1.8.4.2