tree 29cd9cbde448d3d297ab0aa75f5a2a1beb2196bd
parent c51738e2c53fc0659990841dfb1beb4e7ccf6f9d
author Clara Fok <clarafok@google.com> 1625865468 -0700
committer Clara Fok <clarafok@google.com> 1626204532 +0000

Implement LoadResult.Invalid to handle race

For non-initial loads in LimitOffsetPagingSource, loads will run Room
InvalidationTracker's refreshVersionSync to synchronously check if
tables have been invalidated and notify observers. If invalidated,
load will return LoadResult.Invalid.

Paging3 will handle Invalid return type by invalidating the paging
source and closing the page event flow, such that no more loads will be
attempted on this paging source.

Note that refreshVersionSync is a temporary solution for
LimitOffsetPagingSource to check table invalidation. Another solution
that does not require a transaction is in development. Related b/192269858.

Bug: 191806126
Test: ./gradlew :room:integration-tests:room-testapp-kotlin:cC
Test: ./gradlew room:room-paging:cC
Change-Id: I48634ab95949bae608374f5156a4edd0500a74a3