80 lines
2.5 KiB
Go
80 lines
2.5 KiB
Go
package conformance
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import (
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"bytes"
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"context"
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"github.com/filecoin-project/go-state-types/abi"
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"github.com/filecoin-project/go-state-types/crypto"
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"github.com/filecoin-project/test-vectors/schema"
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"github.com/filecoin-project/lotus/chain/vm"
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)
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type ReplayingRand struct {
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reporter Reporter
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recorded schema.Randomness
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fallback vm.Rand
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}
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var _ vm.Rand = (*ReplayingRand)(nil)
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// NewReplayingRand replays recorded randomness when requested, falling back to
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// fixed randomness if the value cannot be found; hence this is a safe
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// backwards-compatible replacement for fixedRand.
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func NewReplayingRand(reporter Reporter, recorded schema.Randomness) *ReplayingRand {
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return &ReplayingRand{
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reporter: reporter,
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recorded: recorded,
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fallback: NewFixedRand(),
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}
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}
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func (r *ReplayingRand) match(requested schema.RandomnessRule) ([]byte, bool) {
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for _, other := range r.recorded {
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if other.On.Kind == requested.Kind &&
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other.On.Epoch == requested.Epoch &&
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other.On.DomainSeparationTag == requested.DomainSeparationTag &&
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bytes.Equal(other.On.Entropy, requested.Entropy) {
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return other.Return, true
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}
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}
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return nil, false
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}
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func (r *ReplayingRand) GetChainRandomness(ctx context.Context, pers crypto.DomainSeparationTag, round abi.ChainEpoch, entropy []byte) ([]byte, error) {
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rule := schema.RandomnessRule{
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Kind: schema.RandomnessChain,
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DomainSeparationTag: int64(pers),
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Epoch: int64(round),
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Entropy: entropy,
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}
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if ret, ok := r.match(rule); ok {
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r.reporter.Logf("returning saved chain randomness: dst=%d, epoch=%d, entropy=%x, result=%x", pers, round, entropy, ret)
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return ret, nil
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}
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r.reporter.Logf("returning fallback chain randomness: dst=%d, epoch=%d, entropy=%x", pers, round, entropy)
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return r.fallback.GetChainRandomness(ctx, pers, round, entropy)
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}
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func (r *ReplayingRand) GetBeaconRandomness(ctx context.Context, pers crypto.DomainSeparationTag, round abi.ChainEpoch, entropy []byte) ([]byte, error) {
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rule := schema.RandomnessRule{
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Kind: schema.RandomnessBeacon,
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DomainSeparationTag: int64(pers),
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Epoch: int64(round),
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Entropy: entropy,
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}
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if ret, ok := r.match(rule); ok {
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r.reporter.Logf("returning saved beacon randomness: dst=%d, epoch=%d, entropy=%x, result=%x", pers, round, entropy, ret)
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return ret, nil
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}
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r.reporter.Logf("returning fallback beacon randomness: dst=%d, epoch=%d, entropy=%x", pers, round, entropy)
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return r.fallback.GetBeaconRandomness(ctx, pers, round, entropy)
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}
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