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authorMichael Haggerty <mhagger@alum.mit.edu>2013-06-20 10:37:51 +0200
committerJunio C Hamano <gitster@pobox.com>2013-06-20 15:50:17 -0700
commit38612532240ecbe1b12e54ca859fed8410ae6de1 (patch)
treef712bce08c4130f25bf4ca5717b82018a7b569fb /cache.h
parentc21d39d7c7eb07eed0be301a72856bff65201256 (diff)
downloadgit-38612532240ecbe1b12e54ca859fed8410ae6de1.tar.gz
add a stat_validity struct
It can sometimes be useful to know whether a path in the filesystem has been updated without going to the work of opening and re-reading its content. We trust the stat() information on disk already to handle index updates, and we can use the same trick here. This patch introduces a "stat_validity" struct which encapsulates the concept of checking the stat-freshness of a file. It is implemented on top of "struct stat_data" to reuse the logic about which stat entries to trust for a particular platform, but hides the complexity behind two simple functions: check and update. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'cache.h')
-rw-r--r--cache.h27
1 files changed, 27 insertions, 0 deletions
diff --git a/cache.h b/cache.h
index f158fed1d8..50f33db2cc 100644
--- a/cache.h
+++ b/cache.h
@@ -1360,4 +1360,31 @@ int checkout_fast_forward(const unsigned char *from,
int sane_execvp(const char *file, char *const argv[]);
+/*
+ * A struct to encapsulate the concept of whether a file has changed
+ * since we last checked it. This uses criteria similar to those used
+ * for the index.
+ */
+struct stat_validity {
+ struct stat_data *sd;
+};
+
+void stat_validity_clear(struct stat_validity *sv);
+
+/*
+ * Returns 1 if the path is a regular file (or a symlink to a regular
+ * file) and matches the saved stat_validity, 0 otherwise. A missing
+ * or inaccessible file is considered a match if the struct was just
+ * initialized, or if the previous update found an inaccessible file.
+ */
+int stat_validity_check(struct stat_validity *sv, const char *path);
+
+/*
+ * Update the stat_validity from a file opened at descriptor fd. If
+ * the file is missing, inaccessible, or not a regular file, then
+ * future calls to stat_validity_check will match iff one of those
+ * conditions continues to be true.
+ */
+void stat_validity_update(struct stat_validity *sv, int fd);
+
#endif /* CACHE_H */