Add git_config_refresh() API to reload config

This adds a new API that allows users to reload the config if the
file has changed on disk.  A new config callback function to
refresh the config was added.

The modified time and file size are used to test if the file needs
to be reloaded (and are now stored in the disk backend object).

In writing tests, just using mtime was a problem / race, so I
wanted to check file size as well.  To support that, I extended
`git_futils_readbuffer_updated` to optionally check file size in
addition to mtime, and I added a new function `git_filebuf_stats`
to fetch the mtime and size for an open filebuf (so that the
config could be easily refreshed after a write).

Lastly, I moved some similar file checking code for attributes
into filebuf.  It is still only being used for attrs, but it
seems potentially reusable, so I thought I'd move it over.

1 files changed, 14 insertions, 20 deletions

diff --git a/src/attr.c b/src/attr.c
index f5e09cc08..50caa1e1b 100644
--- a/src/attr.c
+++ b/src/attr.c
@@ -261,32 +261,26 @@ bool git_attr_cache__is_cached(
 
 static int load_attr_file(
 	const char **data,
-	git_attr_file_stat_sig *sig,
+	git_futils_stat_sig *sig,
 	const char *filename)
 {
 	int error;
 	git_buf content = GIT_BUF_INIT;
-	struct stat st;
 
-	if (p_stat(filename, &st) < 0)
-		return GIT_ENOTFOUND;
+	error = git_futils_stat_sig_needs_reload(sig, filename);
+	if (error < 0)
+		return error;
 
-	if (sig != NULL &&
-		(git_time_t)st.st_mtime == sig->seconds &&
-		(git_off_t)st.st_size == sig->size &&
-		(unsigned int)st.st_ino == sig->ino)
+	/* if error == 0, then file is up to date. By returning GIT_ENOTFOUND,
+	 * we tell the caller not to reparse this file...
+	 */
+	if (!error)
 		return GIT_ENOTFOUND;
 
-	error = git_futils_readbuffer_updated(&content, filename, NULL, NULL);
+	error = git_futils_readbuffer(&content, filename);
 	if (error < 0)
 		return error;
 
-	if (sig != NULL) {
-		sig->seconds = (git_time_t)st.st_mtime;
-		sig->size    = (git_off_t)st.st_size;
-		sig->ino     = (unsigned int)st.st_ino;
-	}
-
 	*data = git_buf_detach(&content);
 
 	return 0;
@@ -386,7 +380,7 @@ int git_attr_cache__push_file(
 	git_attr_cache *cache = git_repository_attr_cache(repo);
 	git_attr_file *file = NULL;
 	git_blob *blob = NULL;
-	git_attr_file_stat_sig st;
+	git_futils_stat_sig sig;
 
 	assert(filename && stack);
 
@@ -409,11 +403,11 @@ int git_attr_cache__push_file(
 
 	if (source == GIT_ATTR_FILE_FROM_FILE) {
 		if (file)
-			memcpy(&st, &file->cache_data.st, sizeof(st));
+			memcpy(&sig, &file->cache_data.sig, sizeof(sig));
 		else
-			memset(&st, 0, sizeof(st));
+			memset(&sig, 0, sizeof(sig));
 
-		error = load_attr_file(&content, &st, filename);
+		error = load_attr_file(&content, &sig, filename);
 	} else {
 		error = load_attr_blob_from_index(&content, &blob,
 			repo, file ? &file->cache_data.oid : NULL, relfile);
@@ -448,7 +442,7 @@ int git_attr_cache__push_file(
 	if (blob)
 		git_oid_cpy(&file->cache_data.oid, git_object_id((git_object *)blob));
 	else
-		memcpy(&file->cache_data.st, &st, sizeof(st));
+		memcpy(&file->cache_data.sig, &sig, sizeof(sig));
 
 finish:
 	/* push file onto vector if we found one*/