lotus/chain/stmgr/searchwait.go

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package stmgr
import (
"context"
"errors"
"fmt"
"github.com/ipfs/go-cid"
"golang.org/x/xerrors"
"github.com/filecoin-project/go-state-types/abi"
"github.com/filecoin-project/lotus/chain/store"
"github.com/filecoin-project/lotus/chain/types"
)
// WaitForMessage blocks until a message appears on chain. It looks backwards in the chain to see if this has already
// happened, with an optional limit to how many epochs it will search. It guarantees that the message has been on
// chain for at least confidence epochs without being reverted before returning.
func (sm *StateManager) WaitForMessage(ctx context.Context, mcid cid.Cid, confidence uint64, lookbackLimit abi.ChainEpoch, allowReplaced bool) (*types.TipSet, *types.MessageReceipt, cid.Cid, error) {
ctx, cancel := context.WithCancel(ctx)
defer cancel()
msg, err := sm.cs.GetCMessage(mcid)
if err != nil {
return nil, nil, cid.Undef, fmt.Errorf("failed to load message: %w", err)
}
tsub := sm.cs.SubHeadChanges(ctx)
head, ok := <-tsub
if !ok {
return nil, nil, cid.Undef, fmt.Errorf("SubHeadChanges stream was invalid")
}
if len(head) != 1 {
return nil, nil, cid.Undef, fmt.Errorf("SubHeadChanges first entry should have been one item")
}
if head[0].Type != store.HCCurrent {
return nil, nil, cid.Undef, fmt.Errorf("expected current head on SHC stream (got %s)", head[0].Type)
}
r, foundMsg, err := sm.tipsetExecutedMessage(head[0].Val, mcid, msg.VMMessage(), allowReplaced)
if err != nil {
return nil, nil, cid.Undef, err
}
if r != nil {
return head[0].Val, r, foundMsg, nil
}
var backTs *types.TipSet
var backRcp *types.MessageReceipt
var backFm cid.Cid
backSearchWait := make(chan struct{})
go func() {
fts, r, foundMsg, err := sm.searchBackForMsg(ctx, head[0].Val, msg, lookbackLimit, allowReplaced)
if err != nil {
log.Warnf("failed to look back through chain for message: %v", err)
return
}
backTs = fts
backRcp = r
backFm = foundMsg
close(backSearchWait)
}()
var candidateTs *types.TipSet
var candidateRcp *types.MessageReceipt
var candidateFm cid.Cid
heightOfHead := head[0].Val.Height()
reverts := map[types.TipSetKey]bool{}
for {
select {
case notif, ok := <-tsub:
if !ok {
return nil, nil, cid.Undef, ctx.Err()
}
for _, val := range notif {
switch val.Type {
case store.HCRevert:
if val.Val.Equals(candidateTs) {
candidateTs = nil
candidateRcp = nil
candidateFm = cid.Undef
}
if backSearchWait != nil {
reverts[val.Val.Key()] = true
}
case store.HCApply:
if candidateTs != nil && val.Val.Height() >= candidateTs.Height()+abi.ChainEpoch(confidence) {
return candidateTs, candidateRcp, candidateFm, nil
}
r, foundMsg, err := sm.tipsetExecutedMessage(val.Val, mcid, msg.VMMessage(), allowReplaced)
if err != nil {
return nil, nil, cid.Undef, err
}
if r != nil {
if confidence == 0 {
return val.Val, r, foundMsg, err
}
candidateTs = val.Val
candidateRcp = r
candidateFm = foundMsg
}
heightOfHead = val.Val.Height()
}
}
case <-backSearchWait:
// check if we found the message in the chain and that is hasn't been reverted since we started searching
if backTs != nil && !reverts[backTs.Key()] {
// if head is at or past confidence interval, return immediately
if heightOfHead >= backTs.Height()+abi.ChainEpoch(confidence) {
return backTs, backRcp, backFm, nil
}
// wait for confidence interval
candidateTs = backTs
candidateRcp = backRcp
candidateFm = backFm
}
reverts = nil
backSearchWait = nil
case <-ctx.Done():
return nil, nil, cid.Undef, ctx.Err()
}
}
}
func (sm *StateManager) SearchForMessage(ctx context.Context, head *types.TipSet, mcid cid.Cid, lookbackLimit abi.ChainEpoch, allowReplaced bool) (*types.TipSet, *types.MessageReceipt, cid.Cid, error) {
msg, err := sm.cs.GetCMessage(mcid)
if err != nil {
return nil, nil, cid.Undef, fmt.Errorf("failed to load message: %w", err)
}
r, foundMsg, err := sm.tipsetExecutedMessage(head, mcid, msg.VMMessage(), allowReplaced)
if err != nil {
return nil, nil, cid.Undef, err
}
if r != nil {
return head, r, foundMsg, nil
}
fts, r, foundMsg, err := sm.searchBackForMsg(ctx, head, msg, lookbackLimit, allowReplaced)
if err != nil {
log.Warnf("failed to look back through chain for message %s", mcid)
return nil, nil, cid.Undef, err
}
if fts == nil {
return nil, nil, cid.Undef, nil
}
return fts, r, foundMsg, nil
}
// searchBackForMsg searches up to limit tipsets backwards from the given
// tipset for a message receipt.
// If limit is
// - 0 then no tipsets are searched
// - 5 then five tipset are searched
// - LookbackNoLimit then there is no limit
func (sm *StateManager) searchBackForMsg(ctx context.Context, from *types.TipSet, m types.ChainMsg, limit abi.ChainEpoch, allowReplaced bool) (*types.TipSet, *types.MessageReceipt, cid.Cid, error) {
limitHeight := from.Height() - limit
noLimit := limit == LookbackNoLimit
cur := from
curActor, err := sm.LoadActor(ctx, m.VMMessage().From, cur)
if err != nil {
return nil, nil, cid.Undef, xerrors.Errorf("failed to load initital tipset")
}
mFromId, err := sm.LookupID(ctx, m.VMMessage().From, from)
if err != nil {
return nil, nil, cid.Undef, xerrors.Errorf("looking up From id address: %w", err)
}
mNonce := m.VMMessage().Nonce
for {
// If we've reached the genesis block, or we've reached the limit of
// how far back to look
if cur.Height() == 0 || !noLimit && cur.Height() <= limitHeight {
// it ain't here!
return nil, nil, cid.Undef, nil
}
select {
case <-ctx.Done():
return nil, nil, cid.Undef, nil
default:
}
// we either have no messages from the sender, or the latest message we found has a lower nonce than the one being searched for,
// either way, no reason to lookback, it ain't there
if curActor == nil || curActor.Nonce == 0 || curActor.Nonce < mNonce {
return nil, nil, cid.Undef, nil
}
pts, err := sm.cs.LoadTipSet(cur.Parents())
if err != nil {
return nil, nil, cid.Undef, xerrors.Errorf("failed to load tipset during msg wait searchback: %w", err)
}
act, err := sm.LoadActor(ctx, mFromId, pts)
actorNoExist := errors.Is(err, types.ErrActorNotFound)
if err != nil && !actorNoExist {
return nil, nil, cid.Cid{}, xerrors.Errorf("failed to load the actor: %w", err)
}
// check that between cur and parent tipset the nonce fell into range of our message
if actorNoExist || (curActor.Nonce > mNonce && act.Nonce <= mNonce) {
r, foundMsg, err := sm.tipsetExecutedMessage(cur, m.Cid(), m.VMMessage(), allowReplaced)
if err != nil {
return nil, nil, cid.Undef, xerrors.Errorf("checking for message execution during lookback: %w", err)
}
if r != nil {
return cur, r, foundMsg, nil
}
}
cur = pts
curActor = act
}
}
func (sm *StateManager) tipsetExecutedMessage(ts *types.TipSet, msg cid.Cid, vmm *types.Message, allowReplaced bool) (*types.MessageReceipt, cid.Cid, error) {
// The genesis block did not execute any messages
if ts.Height() == 0 {
return nil, cid.Undef, nil
}
pts, err := sm.cs.LoadTipSet(ts.Parents())
if err != nil {
return nil, cid.Undef, err
}
cm, err := sm.cs.MessagesForTipset(pts)
if err != nil {
return nil, cid.Undef, err
}
for ii := range cm {
// iterate in reverse because we going backwards through the chain
i := len(cm) - ii - 1
m := cm[i]
if m.VMMessage().From == vmm.From { // cheaper to just check origin first
if m.VMMessage().Nonce == vmm.Nonce {
if !m.VMMessage().EqualCall(vmm) {
// this is an entirely different message, fail
return nil, cid.Undef, xerrors.Errorf("found message with equal nonce as the one we are looking for that is NOT a valid replacement message (F:%s n %d, TS: %s n%d)",
msg, vmm.Nonce, m.Cid(), m.VMMessage().Nonce)
}
if m.Cid() != msg {
if !allowReplaced {
log.Warnw("found message with equal nonce and call params but different CID",
"wanted", msg, "found", m.Cid(), "nonce", vmm.Nonce, "from", vmm.From)
return nil, cid.Undef, xerrors.Errorf("found message with equal nonce as the one we are looking for (F:%s n %d, TS: %s n%d)",
msg, vmm.Nonce, m.Cid(), m.VMMessage().Nonce)
}
}
pr, err := sm.cs.GetParentReceipt(ts.Blocks()[0], i)
if err != nil {
return nil, cid.Undef, err
}
return pr, m.Cid(), nil
}
if m.VMMessage().Nonce < vmm.Nonce {
return nil, cid.Undef, nil // don't bother looking further
}
}
}
return nil, cid.Undef, nil
}