cnct: persist anchor resolutions

contractcourt/briefcase.go

@@ -29,6 +29,11 @@ type ContractResolutions struct {
 	// HtlcResolutions contains all data required to fully resolve any
 	// incoming+outgoing HTLC's present within the commitment transaction.
 	HtlcResolutions lnwallet.HtlcResolutions
+
+	// AnchorResolution contains the data required to sweep the anchor
+	// output. If the channel type doesn't include anchors, the value of
+	// this field will be nil.
+	AnchorResolution *lnwallet.AnchorResolution
 }
 
 // IsEmpty returns true if the set of resolutions is "empty". A resolution is
@@ -37,7 +42,8 @@ type ContractResolutions struct {
 func (c *ContractResolutions) IsEmpty() bool {
 	return c.CommitResolution == nil &&
 		len(c.HtlcResolutions.IncomingHTLCs) == 0 &&
-		len(c.HtlcResolutions.OutgoingHTLCs) == 0
+		len(c.HtlcResolutions.OutgoingHTLCs) == 0 &&
+		c.AnchorResolution == nil
 }
 
 // ArbitratorLog is the primary source of persistent storage for the
@@ -263,6 +269,10 @@ var (
 	// the full set of resolutions for a channel.
 	resolutionsKey = []byte("resolutions")
 
+	// anchorResolutionKey is the key under the logScope that we'll use to
+	// store the anchor resolution, if any.
+	anchorResolutionKey = []byte("anchor-resolution")
+
 	// actionsBucketKey is the key under the logScope that we'll use to
 	// store all chain actions once they're determined.
 	actionsBucketKey = []byte("chain-actions")
@@ -630,7 +640,26 @@ func (b *boltArbitratorLog) LogContractResolutions(c *ContractResolutions) error
 			}
 		}
 
-		return scopeBucket.Put(resolutionsKey, b.Bytes())
+		err = scopeBucket.Put(resolutionsKey, b.Bytes())
+		if err != nil {
+			return err
+		}
+
+		// Write out the anchor resolution if present.
+		if c.AnchorResolution != nil {
+			var b bytes.Buffer
+			err := encodeAnchorResolution(&b, c.AnchorResolution)
+			if err != nil {
+				return err
+			}
+
+			err = scopeBucket.Put(anchorResolutionKey, b.Bytes())
+			if err != nil {
+				return err
+			}
+		}
+
+		return nil
 	})
 }
 
@@ -710,6 +739,18 @@ func (b *boltArbitratorLog) FetchContractResolutions() (*ContractResolutions, er
 			}
 		}
 
+		anchorResBytes := scopeBucket.Get(anchorResolutionKey)
+		if anchorResBytes != nil {
+			c.AnchorResolution = &lnwallet.AnchorResolution{}
+			resReader := bytes.NewReader(anchorResBytes)
+			err := decodeAnchorResolution(
+				resReader, c.AnchorResolution,
+			)
+			if err != nil {
+				return err
+			}
+		}
+
 		return nil
 	})
 	if err != nil {
@@ -1045,6 +1086,35 @@ func decodeCommitResolution(r io.Reader,
 	return binary.Read(r, endian, &c.MaturityDelay)
 }
 
+func encodeAnchorResolution(w io.Writer,
+	a *lnwallet.AnchorResolution) error {
+
+	if _, err := w.Write(a.CommitAnchor.Hash[:]); err != nil {
+		return err
+	}
+	err := binary.Write(w, endian, a.CommitAnchor.Index)
+	if err != nil {
+		return err
+	}
+
+	return input.WriteSignDescriptor(w, &a.AnchorSignDescriptor)
+}
+
+func decodeAnchorResolution(r io.Reader,
+	a *lnwallet.AnchorResolution) error {
+
+	_, err := io.ReadFull(r, a.CommitAnchor.Hash[:])
+	if err != nil {
+		return err
+	}
+	err = binary.Read(r, endian, &a.CommitAnchor.Index)
+	if err != nil {
+		return err
+	}
+
+	return input.ReadSignDescriptor(r, &a.AnchorSignDescriptor)
+}
+
 func encodeHtlcSetKey(w io.Writer, h *HtlcSetKey) error {
 	err := binary.Write(w, endian, h.IsRemote)
 	if err != nil {

contractcourt/briefcase_test.go

@@ -46,6 +46,15 @@ var (
 		Index: 2,
 	}
 
+	testChanPoint3 = wire.OutPoint{
+		Hash: chainhash.Hash{
+			0x48, 0x59, 0xe6, 0x96, 0x31, 0x13, 0xa1, 0x17,
+			0x51, 0xb6, 0x37, 0xd8, 0xfc, 0xd2, 0xc6, 0xda,
+			0x2d, 0xe7, 0x93, 0xe4,
+		},
+		Index: 3,
+	}
+
 	testPreimage = [32]byte{
 		0x52, 0xb6, 0x37, 0xd8, 0xfc, 0xd2, 0xc6, 0xda,
 		0x48, 0x59, 0xe6, 0x96, 0x31, 0x13, 0xa1, 0x17,
@@ -540,6 +549,10 @@ func TestContractResolutionsStorage(t *testing.T) {
 				},
 			},
 		},
+		AnchorResolution: &lnwallet.AnchorResolution{
+			CommitAnchor:         testChanPoint3,
+			AnchorSignDescriptor: testSignDesc,
+		},
 	}
 
 	// First make sure that fetching unlogged contract resolutions will

contractcourt/channel_arbitrator.go

@@ -2090,6 +2090,7 @@ func (c *ChannelArbitrator) channelAttendant(bestHeight int32) {
 				CommitHash:       closeTx.TxHash(),
 				CommitResolution: closeInfo.CommitResolution,
 				HtlcResolutions:  *closeInfo.HtlcResolutions,
+				AnchorResolution: closeInfo.AnchorResolution,
 			}
 
 			// When processing a unilateral close event, we'll
@@ -2156,6 +2157,7 @@ func (c *ChannelArbitrator) channelAttendant(bestHeight int32) {
 				CommitHash:       *uniClosure.SpenderTxHash,
 				CommitResolution: uniClosure.CommitResolution,
 				HtlcResolutions:  *uniClosure.HtlcResolutions,
+				AnchorResolution: uniClosure.AnchorResolution,
 			}
 
 			// When processing a unilateral close event, we'll