ceremonyclient/pebble/internal/base/lazy_value_test.go

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2024-01-03 07:31:42 +00:00
// Copyright 2022 The LevelDB-Go and Pebble Authors. All rights reserved. Use
// of this source code is governed by a BSD-style license that can be found in
// the LICENSE file.
package base
import (
"bytes"
"testing"
"unsafe"
"github.com/stretchr/testify/require"
)
type valueFetcherFunc func(
handle []byte, valLen int32, buf []byte) (val []byte, callerOwned bool, err error)
func (v valueFetcherFunc) Fetch(
handle []byte, valLen int32, buf []byte,
) (val []byte, callerOwned bool, err error) {
return v(handle, valLen, buf)
}
func TestLazyValue(t *testing.T) {
// Both 40 and 48 bytes makes iteration benchmarks like
// BenchmarkIteratorScan/keys=1000,r-amp=1,key-types=points-only 75%
// slower.
require.True(t, unsafe.Sizeof(LazyValue{}) <= 32)
fooBytes1 := []byte("foo")
fooLV1 := MakeInPlaceValue(fooBytes1)
require.Equal(t, 3, fooLV1.Len())
_, hasAttr := fooLV1.TryGetShortAttribute()
require.False(t, hasAttr)
fooLV2, fooBytes2 := fooLV1.Clone(nil, &LazyFetcher{})
require.Equal(t, 3, fooLV2.Len())
_, hasAttr = fooLV2.TryGetShortAttribute()
require.False(t, hasAttr)
require.Equal(t, fooLV1.InPlaceValue(), fooLV2.InPlaceValue())
getValue := func(lv LazyValue, expectedCallerOwned bool) []byte {
v, callerOwned, err := lv.Value(nil)
require.NoError(t, err)
require.Equal(t, expectedCallerOwned, callerOwned)
return v
}
require.Equal(t, getValue(fooLV1, false), getValue(fooLV2, false))
fooBytes2[0] = 'b'
require.False(t, bytes.Equal(fooLV1.InPlaceValue(), fooLV2.InPlaceValue()))
for _, callerOwned := range []bool{false, true} {
numCalls := 0
fooLV3 := LazyValue{
ValueOrHandle: []byte("foo-handle"),
Fetcher: &LazyFetcher{
Fetcher: valueFetcherFunc(
func(handle []byte, valLen int32, buf []byte) ([]byte, bool, error) {
numCalls++
require.Equal(t, []byte("foo-handle"), handle)
require.Equal(t, int32(3), valLen)
return fooBytes1, callerOwned, nil
}),
Attribute: AttributeAndLen{ValueLen: 3, ShortAttribute: 7},
},
}
require.Equal(t, []byte("foo"), getValue(fooLV3, callerOwned))
require.Equal(t, 1, numCalls)
require.Equal(t, []byte("foo"), getValue(fooLV3, callerOwned))
require.Equal(t, 1, numCalls)
require.Equal(t, 3, fooLV3.Len())
attr, hasAttr := fooLV3.TryGetShortAttribute()
require.True(t, hasAttr)
require.Equal(t, ShortAttribute(7), attr)
}
}