reftable/stack: reorder swapping in the reloaded stack contents

The code flow of how we swap in the reloaded stack contents is somewhat
convoluted because we switch back and forth between swapping in
different parts of the stack.

Reorder the code to simplify it. We now first close and unlink the old
tables which do not get reused before we update the stack to point to
the new stack.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/reftable/stack.c b/reftable/stack.c
index 8e85f8b4d99708507486a2a63a0607a012a0ee32..02472222589ffec4da1c1721d804aa8859b8bbae 100644 (file)
--- a/reftable/stack.c
+++ b/reftable/stack.c
@@ -273,30 +273,34 @@ static int reftable_stack_reload_once(struct reftable_stack *st,
        if (err < 0)
                goto done;
 
-       st->readers_len = new_readers_len;
-       if (st->merged)
-               reftable_merged_table_free(st->merged);
-       if (st->readers) {
-               reftable_free(st->readers);
-       }
-       st->readers = new_readers;
-       new_readers = NULL;
-       new_readers_len = 0;
-
-       new_merged->suppress_deletions = 1;
-       st->merged = new_merged;
+       /*
+        * Close the old, non-reused readers and proactively try to unlink
+        * them. This is done for systems like Windows, where the underlying
+        * file of such an open reader wouldn't have been possible to be
+        * unlinked by the compacting process.
+        */
        for (i = 0; i < cur_len; i++) {
                if (cur[i]) {
                        const char *name = reader_name(cur[i]);
                        stack_filename(&table_path, st, name);
-
                        reftable_reader_decref(cur[i]);
-
-                       /* On Windows, can only unlink after closing. */
                        unlink(table_path.buf);
                }
        }
 
+       /* Update the stack to point to the new tables. */
+       if (st->merged)
+               reftable_merged_table_free(st->merged);
+       new_merged->suppress_deletions = 1;
+       st->merged = new_merged;
+
+       if (st->readers)
+               reftable_free(st->readers);
+       st->readers = new_readers;
+       st->readers_len = new_readers_len;
+       new_readers = NULL;
+       new_readers_len = 0;
+
 done:
        for (i = 0; i < new_readers_len; i++)
                reftable_reader_decref(new_readers[i]);