reftable/writer: unify releasing memory

There are two code paths which release memory of the reftable writer:

  - `reftable_writer_close()` releases internal state after it has
    written data.

  - `reftable_writer_free()` releases the block that was written to and
    the writer itself.

Both code paths free different parts of the writer, and consequently the
caller must make sure to call both. And while callers mostly do this
already, this falls apart when a write failure causes the caller to skip
calling `reftable_write_close()`.

Introduce a new function `reftable_writer_release()` that releases all
internal state and call it from both paths. Like this it is fine for the
caller to not call `reftable_writer_close()`.

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

diff --git a/reftable/writer.c b/reftable/writer.c
index d347ec4cc61a19860df7f95431c0124d85bfd1fe..4eeb73644521900e6f0e70b7eb680eb94c6fc5a9 100644 (file)
--- a/reftable/writer.c
+++ b/reftable/writer.c
@@ -149,11 +149,21 @@ void reftable_writer_set_limits(struct reftable_writer *w, uint64_t min,
        w->max_update_index = max;
 }
 
+static void writer_release(struct reftable_writer *w)
+{
+       if (w) {
+               reftable_free(w->block);
+               w->block = NULL;
+               block_writer_release(&w->block_writer_data);
+               w->block_writer = NULL;
+               writer_clear_index(w);
+               strbuf_release(&w->last_key);
+       }
+}
+
 void reftable_writer_free(struct reftable_writer *w)
 {
-       if (!w)
-               return;
-       reftable_free(w->block);
+       writer_release(w);
        reftable_free(w);
 }
 
@@ -643,16 +653,13 @@ int reftable_writer_close(struct reftable_writer *w)
        }
 
 done:
-       /* free up memory. */
-       block_writer_release(&w->block_writer_data);
-       writer_clear_index(w);
-       strbuf_release(&w->last_key);
+       writer_release(w);
        return err;
 }
 
 static void writer_clear_index(struct reftable_writer *w)
 {
-       for (size_t i = 0; i < w->index_len; i++)
+       for (size_t i = 0; w->index && i < w->index_len; i++)
                strbuf_release(&w->index[i].last_key);
        FREE_AND_NULL(w->index);
        w->index_len = 0;