lnwallet: rewrite channelState to bool for clarity

Over the last few commits we have systematically eliminated all but
two states. This allows us to replace it with a boolean to encode
the two remaining states. We would like to be able to eliminate this
field entirely, but doing so requires being able to prove that the
concurrent request block is necessary. This is more difficult and
will be left to future commits.

lnwallet/channel.go

@@ -153,22 +153,6 @@ func (e *ErrCommitSyncLocalDataLoss) Error() string {
 		e.CommitPoint.SerializeCompressed())
 }
 
-// channelState is an enum like type which represents the current state of a
-// particular channel.
-// TODO(roasbeef): actually update state
-type channelState uint8
-
-const (
-	// channelOpen represents an open, active channel capable of
-	// sending/receiving HTLCs.
-	channelOpen channelState = iota
-
-	// channelClosed represents a channel which has been fully closed. Note
-	// that before a channel can be closed, ALL pending HTLCs must be
-	// settled/removed.
-	channelClosed
-)
-
 // PaymentHash represents the sha256 of a random value. This hash is used to
 // uniquely track incoming/outgoing payments within this channel, as well as
 // payments requested by the wallet/daemon.
@@ -1267,7 +1251,7 @@ type LightningChannel struct {
 	// the commitment transaction that spends the multi-sig output.
 	signDesc *input.SignDescriptor
 
-	status channelState
+	isClosed bool
 
 	// ChanPoint is the funding outpoint of this channel.
 	ChanPoint *wire.OutPoint
@@ -1522,7 +1506,7 @@ func (lc *LightningChannel) createSignDesc() error {
 // events do so properly.
 func (lc *LightningChannel) ResetState() {
 	lc.Lock()
-	lc.status = channelOpen
+	lc.isClosed = false
 	lc.Unlock()
 }
 
@@ -7577,9 +7561,8 @@ func (lc *LightningChannel) ForceClose() (*LocalForceCloseSummary, error) {
 			"summary: %w", err)
 	}
 
-	// Set the channel state to indicate that the channel is now in a
+	// Mark the channel as closed to block future closure requests.
-	// contested state.
+	lc.isClosed = true
-	lc.status = channelClosed
 
 	return summary, nil
 }
@@ -7773,8 +7756,8 @@ func (lc *LightningChannel) CreateCloseProposal(proposedFee btcutil.Amount,
 	lc.Lock()
 	defer lc.Unlock()
 
-	// If we've already closed the channel, then ignore this request.
+	// If we're already closing the channel, then ignore this request.
-	if lc.status == channelClosed {
+	if lc.isClosed {
 		// TODO(roasbeef): check to ensure no pending payments
 		return nil, nil, 0, ErrChanClosing
 	}
@@ -7857,8 +7840,8 @@ func (lc *LightningChannel) CompleteCooperativeClose(
 	lc.Lock()
 	defer lc.Unlock()
 
-	// If the channel is already closed, then ignore this request.
+	// If the channel is already closing, then ignore this request.
-	if lc.status == channelClosed {
+	if lc.isClosed {
 		// TODO(roasbeef): check to ensure no pending payments
 		return nil, 0, ErrChanClosing
 	}
@@ -7962,7 +7945,7 @@ func (lc *LightningChannel) CompleteCooperativeClose(
 	// As the transaction is sane, and the scripts are valid we'll mark the
 	// channel now as closed as the closure transaction should get into the
 	// chain in a timely manner and possibly be re-broadcast by the wallet.
-	lc.status = channelClosed
+	lc.isClosed = true
 
 	return closeTx, ourBalance, nil
 }

lnwallet/channel_test.go

@@ -2147,8 +2147,8 @@ func TestCooperativeCloseDustAdherence(t *testing.T) {
 	}
 
 	resetChannelState := func() {
-		aliceChannel.status = channelOpen
+		aliceChannel.isClosed = false
-		bobChannel.status = channelOpen
+		bobChannel.isClosed = false
 	}
 
 	setBalances := func(aliceBalance, bobBalance lnwire.MilliSatoshi) {