reftable/stack: register compacted tables as tempfiles

We do not register tables resulting from stack compaction with the
tempfile API. Those tables will thus not be deleted in case Git gets
killed.

Refactor the code to register compacted tables as tempfiles.

Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: pks-t

reftable/stack.c

@@ -827,51 +827,56 @@ uint64_t reftable_stack_next_update_index(struct reftable_stack *st)
 
 static int stack_compact_locked(struct reftable_stack *st,
 				size_t first, size_t last,
-				struct strbuf *temp_tab,
-				struct reftable_log_expiry_config *config)
+				struct reftable_log_expiry_config *config,
+				struct tempfile **tab_file_out)
 {
 	struct strbuf next_name = STRBUF_INIT;
-	int tab_fd = -1;
+	struct strbuf tab_file_path = STRBUF_INIT;
 	struct reftable_writer *wr = NULL;
-	int err = 0;
+	struct tempfile *tab_file;
+	int tab_fd, err = 0;
 
 	format_name(&next_name,
 		    reftable_reader_min_update_index(st->readers[first]),
 		    reftable_reader_max_update_index(st->readers[last]));
+	stack_filename(&tab_file_path, st, next_name.buf);
+	strbuf_addstr(&tab_file_path, ".temp.XXXXXX");
 
-	stack_filename(temp_tab, st, next_name.buf);
-	strbuf_addstr(temp_tab, ".temp.XXXXXX");
+	tab_file = mks_tempfile(tab_file_path.buf);
+	if (!tab_file) {
+		err = REFTABLE_IO_ERROR;
+		goto done;
+	}
+	tab_fd = get_tempfile_fd(tab_file);
 
-	tab_fd = mkstemp(temp_tab->buf);
 	if (st->config.default_permissions &&
-	    chmod(temp_tab->buf, st->config.default_permissions) < 0) {
+	    chmod(get_tempfile_path(tab_file), st->config.default_permissions) < 0) {
 		err = REFTABLE_IO_ERROR;
 		goto done;
 	}
 
-	wr = reftable_new_writer(reftable_fd_write, reftable_fd_flush, &tab_fd, &st->config);
-
+	wr = reftable_new_writer(reftable_fd_write, reftable_fd_flush,
+				 &tab_fd, &st->config);
 	err = stack_write_compact(st, wr, first, last, config);
 	if (err < 0)
 		goto done;
+
 	err = reftable_writer_close(wr);
 	if (err < 0)
 		goto done;
 
-	err = close(tab_fd);
-	tab_fd = 0;
+	err = close_tempfile_gently(tab_file);
+	if (err < 0)
+		goto done;
+
+	*tab_file_out = tab_file;
+	tab_file = NULL;
 
 done:
+	delete_tempfile(&tab_file);
 	reftable_writer_free(wr);
-	if (tab_fd > 0) {
-		close(tab_fd);
-		tab_fd = 0;
-	}
-	if (err != 0 && temp_tab->len > 0) {
-		unlink(temp_tab->buf);
-		strbuf_release(temp_tab);
-	}
 	strbuf_release(&next_name);
+	strbuf_release(&tab_file_path);
 	return err;
 }
 
@@ -979,12 +984,12 @@ static int stack_compact_range(struct reftable_stack *st,
 			       struct reftable_log_expiry_config *expiry)
 {
 	struct strbuf tables_list_buf = STRBUF_INIT;
-	struct strbuf new_table_temp_path = STRBUF_INIT;
 	struct strbuf new_table_name = STRBUF_INIT;
 	struct strbuf new_table_path = STRBUF_INIT;
 	struct strbuf table_name = STRBUF_INIT;
 	struct lock_file tables_list_lock = LOCK_INIT;
 	struct lock_file *table_locks = NULL;
+	struct tempfile *new_table = NULL;
 	int is_empty_table = 0, err = 0;
 	size_t i;
 
@@ -1059,7 +1064,7 @@ static int stack_compact_range(struct reftable_stack *st,
 	 * these tables may end up with an empty new table in case tombstones
 	 * end up cancelling out all refs in that range.
 	 */
-	err = stack_compact_locked(st, first, last, &new_table_temp_path, expiry);
+	err = stack_compact_locked(st, first, last, expiry, &new_table);
 	if (err < 0) {
 		if (err != REFTABLE_EMPTY_TABLE_ERROR)
 			goto done;
@@ -1099,7 +1104,7 @@ static int stack_compact_range(struct reftable_stack *st,
 		strbuf_addstr(&new_table_name, ".ref");
 		stack_filename(&new_table_path, st, new_table_name.buf);
 
-		err = rename(new_table_temp_path.buf, new_table_path.buf);
+		err = rename_tempfile(&new_table, new_table_path.buf);
 		if (err < 0) {
 			err = REFTABLE_IO_ERROR;
 			goto done;
@@ -1166,9 +1171,10 @@ static int stack_compact_range(struct reftable_stack *st,
 		rollback_lock_file(&table_locks[i - first]);
 	reftable_free(table_locks);
 
+	delete_tempfile(&new_table);
 	strbuf_release(&new_table_name);
 	strbuf_release(&new_table_path);
-	strbuf_release(&new_table_temp_path);
+
 	strbuf_release(&tables_list_buf);
 	strbuf_release(&table_name);
 	return err;