files_ref_store: put the packed files lock directly in this struct

Instead of using a global `lock_file` instance for the main "packed-refs" file and using a pointer in `files_ref_store` to keep track of whether it is locked, embed the `lock_file` instance directly in the `files_ref_store` struct and use the new `is_lock_file_locked()` function to keep track of whether it is locked. This keeps related data together and makes the main reference store less of a special case. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Michael Haggerty committed May 22, 2017 at 16:17 UTC 00d174489e9905411dbae5f895758f2ca489bd9f
1 file changed +11 -18
refs/files-backend.c
+11 -18
@@ -63,16 +63,12 @@ struct files_ref_store {
63 struct packed_ref_cache *packed;
64
65 /*
66 - * Iff the packed-refs file associated with this instance is
67 - * currently locked for writing, this points at the associated
68 - * lock (which is owned by somebody else).
66 + * Lock used for the "packed-refs" file. Note that this (and
67 + * thus the enclosing `files_ref_store`) must not be freed.
68 */
70 - struct lock_file *packed_refs_lock;
69 + struct lock_file packed_refs_lock;
70 };
71
73 -/* Lock used for the main packed-refs file: */
74 -static struct lock_file packlock;
75 -
72 /*
73 * Increment the reference count of *packed_refs.
74 */
@@ -102,7 +98,7 @@ static void clear_packed_ref_cache(struct files_ref_store *refs)
98 if (refs->packed) {
99 struct packed_ref_cache *packed_refs = refs->packed;
100
105 - if (refs->packed_refs_lock)
101 + if (is_lock_file_locked(&refs->packed_refs_lock))
102 die("BUG: packed-ref cache cleared while locked");
103 refs->packed = NULL;
104 release_packed_ref_cache(packed_refs);
@@ -394,7 +390,7 @@ static void add_packed_ref(struct files_ref_store *refs,
390 {
391 struct packed_ref_cache *packed_ref_cache = get_packed_ref_cache(refs);
392
397 - if (!refs->packed_refs_lock)
393 + if (!is_lock_file_locked(&refs->packed_refs_lock))
394 die("BUG: packed refs not locked");
395 add_ref_entry(get_packed_ref_dir(packed_ref_cache),
396 create_ref_entry(refname, oid, REF_ISPACKED, 1));
@@ -1288,7 +1284,7 @@ static int lock_packed_refs(struct files_ref_store *refs, int flags)
1284 }
1285
1286 if (hold_lock_file_for_update_timeout(
1291 - &packlock, files_packed_refs_path(refs),
1287 + &refs->packed_refs_lock, files_packed_refs_path(refs),
1288 flags, timeout_value) < 0)
1289 return -1;
1290 /*
@@ -1298,7 +1294,6 @@ static int lock_packed_refs(struct files_ref_store *refs, int flags)
1294 * the packed-refs file.
1295 */
1296 packed_ref_cache = get_packed_ref_cache(refs);
1301 - refs->packed_refs_lock = &packlock;
1297 /* Increment the reference count to prevent it from being freed: */
1298 acquire_packed_ref_cache(packed_ref_cache);
1299 return 0;
@@ -1321,10 +1316,10 @@ static int commit_packed_refs(struct files_ref_store *refs)
1316
1317 files_assert_main_repository(refs, "commit_packed_refs");
1318
1324 - if (!refs->packed_refs_lock)
1319 + if (!is_lock_file_locked(&refs->packed_refs_lock))
1320 die("BUG: packed-refs not locked");
1321
1327 - out = fdopen_lock_file(refs->packed_refs_lock, "w");
1322 + out = fdopen_lock_file(&refs->packed_refs_lock, "w");
1323 if (!out)
1324 die_errno("unable to fdopen packed-refs descriptor");
1325
@@ -1342,11 +1337,10 @@ static int commit_packed_refs(struct files_ref_store *refs)
1337 if (ok != ITER_DONE)
1338 die("error while iterating over references");
1339
1345 - if (commit_lock_file(refs->packed_refs_lock)) {
1340 + if (commit_lock_file(&refs->packed_refs_lock)) {
1341 save_errno = errno;
1342 error = -1;
1343 }
1349 - refs->packed_refs_lock = NULL;
1344 release_packed_ref_cache(packed_ref_cache);
1345 errno = save_errno;
1346 return error;
@@ -1364,10 +1358,9 @@ static void rollback_packed_refs(struct files_ref_store *refs)
1358
1359 files_assert_main_repository(refs, "rollback_packed_refs");
1360
1367 - if (!refs->packed_refs_lock)
1361 + if (!is_lock_file_locked(&refs->packed_refs_lock))
1362 die("BUG: packed-refs not locked");
1369 - rollback_lock_file(refs->packed_refs_lock);
1370 - refs->packed_refs_lock = NULL;
1363 + rollback_lock_file(&refs->packed_refs_lock);
1364 release_packed_ref_cache(packed_ref_cache);
1365 clear_packed_ref_cache(refs);
1366 }