tree 27c6a89e92869f640f9d8787f7dd1b6d9097dde5
parent f61577078011f8c1221fabe922843354c6aa7ce2
author Takahiro <hogehoge@gachapin.jp> 1677510853 +0000
committer Dawn LUCI CQ <dawn-scoped@luci-project-accounts.iam.gserviceaccount.com> 1677510853 +0000

Refcount check in Buffer map async in Wire

If buffer is released and the external refcount reaches 0 while
buffer map state is pending map in Wire, the map async callback
is fired with destroyed-before-callback status from the buffer
destructor.

It is possible to call another MapAsync in the callback. At that
time the pointer is still valid because the internal refcount is
not 0 yet.

The behavior of MapAsync should be undefined if external refcount
is 0. This commit adds an assert to check whether external
refcount is 0 in Buffer::MapAsync() in Wire. Ending up with
assertion error may be reasonable.

This commit also adds protected GetRefcount() method to
ObjectBase to allow derived classes to check the refcount.

bug: dawn:1624
Change-Id: I95411a7be2093ba7bb2bb45b466f17f1ebac0ca9
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/119961
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>