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All tests for our recent CursorWindow changes have been passing for
ARM 64-bit builds, but they weren't executed against 32-bit x86
builds until after merged.
It's not actually safe to use the "off_t" type, so we need to cast
to "int32_t" when doing checks against possible-negative values,
such as in allocRow().
We also add tests that verify negative rows/columns are identified
as invalid positions, which requires that we check the resulting
pointer against both mSlotsEnd and mSlotsStart.
Bug: 169251528, 171276404, 171275409
Test: atest libandroidfw_tests:CursorWindowTest
Test: atest CtsDatabaseTestCases
Change-Id: Iea5f7546850f691e183fbb6e6d0952cd02b00d0f
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The original CursorWindow implementation was created in Android 1.0
and has remained relatively unchanged since then. Unfortunately that
design results in very poor performance on large windows, since
reading or writing each FieldSlot is O(row/100) to traverse through
a chain of RowSlotChunks. It's also memory-inefficient due to how
it allocates RowSlotChunks in 404 byte chunks, even when there's only
a single row to store.
This change is a complete redesign of the CursorWindow internals to
use a "heap-and-stack" style approach, where a "heap" of strings
and blobs increment up from the bottom of the window while a "stack"
of FieldSlots increment down from the top of the window.
The included benchmarks show the following improvements, ensuring
no regressions for small windows, while offering very dramatic
improvements for larger windows:
Big cores Little cores
4x4 cursor no regression no regression
1024x4 cursor 2.2x faster 2.0x faster
16384x4 cursor 48.5x faster 24.4x faster
Detailed unit testing is also included to ensure that the rewrite
behaves correctly.
Bug: 169251528
Test: atest libandroidfw_tests
Test: atest CtsDatabaseTestCases
Test: atest FrameworksCoreTests:android.database
Test: ./frameworks/base/libs/hwui/tests/scripts/prep_generic.sh little && atest libandroidfw_benchmarks
Test: ./frameworks/base/libs/hwui/tests/scripts/prep_generic.sh little && atest CorePerfTests:android.database.CrossProcessCursorPerfTest
Change-Id: I90dff31fd550130dae917a33e0e1fa684e15c107
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