contractcourt: pass in optional txns to lookups required for arb startup

To allow us to grab all of the information we need for our channel arbs
in a more efficient way on startup, we add an optional tx to our lookup
functions required on start.

contractcourt/briefcase.go

@@ -54,8 +54,10 @@ type ArbitratorLog interface {
 	// TODO(roasbeef): document on interface the errors expected to be
 	// returned
 
-	// CurrentState returns the current state of the ChannelArbitrator.
+	// CurrentState returns the current state of the ChannelArbitrator. It
-	CurrentState() (ArbitratorState, error)
+	// takes an optional database transaction, which will be used if it is
+	// non-nil, otherwise the lookup will be done in its own transaction.
+	CurrentState(tx kvdb.RTx) (ArbitratorState, error)
 
 	// CommitState persists, the current state of the chain attendant.
 	CommitState(ArbitratorState) error
@@ -96,8 +98,10 @@ type ArbitratorLog interface {
 	InsertConfirmedCommitSet(c *CommitSet) error
 
 	// FetchConfirmedCommitSet fetches the known confirmed active HTLC set
-	// from the database.
+	// from the database. It takes an optional database transaction, which
-	FetchConfirmedCommitSet() (*CommitSet, error)
+	// will be used if it is non-nil, otherwise the lookup will be done in
+	// its own transaction.
+	FetchConfirmedCommitSet(tx kvdb.RTx) (*CommitSet, error)
 
 	// FetchChainActions attempts to fetch the set of previously stored
 	// chain actions. We'll use this upon restart to properly advance our
@@ -412,27 +416,28 @@ func (b *boltArbitratorLog) writeResolver(contractBucket kvdb.RwBucket,
 	return contractBucket.Put(resKey, buf.Bytes())
 }
 
-// CurrentState returns the current state of the ChannelArbitrator.
+// CurrentState returns the current state of the ChannelArbitrator. It takes an
+// optional database transaction, which will be used if it is non-nil, otherwise
+// the lookup will be done in its own transaction.
 //
 // NOTE: Part of the ContractResolver interface.
-func (b *boltArbitratorLog) CurrentState() (ArbitratorState, error) {
+func (b *boltArbitratorLog) CurrentState(tx kvdb.RTx) (ArbitratorState, error) {
-	var s ArbitratorState
+	var (
-	err := kvdb.View(b.db, func(tx kvdb.RTx) error {
+		s   ArbitratorState
-		scopeBucket := tx.ReadBucket(b.scopeKey[:])
+		err error
-		if scopeBucket == nil {
+	)
-			return errScopeBucketNoExist
-		}
 
-		stateBytes := scopeBucket.Get(stateKey)
+	if tx != nil {
-		if stateBytes == nil {
+		s, err = b.currentState(tx)
-			return nil
+	} else {
-		}
+		err = kvdb.View(b.db, func(tx kvdb.RTx) error {
+			s, err = b.currentState(tx)
+			return err
+		}, func() {
+			s = 0
+		})
+	}
 
-		s = ArbitratorState(stateBytes[0])
-		return nil
-	}, func() {
-		s = 0
-	})
 	if err != nil && err != errScopeBucketNoExist {
 		return s, err
 	}
@@ -440,6 +445,20 @@ func (b *boltArbitratorLog) CurrentState() (ArbitratorState, error) {
 	return s, nil
 }
 
+func (b *boltArbitratorLog) currentState(tx kvdb.RTx) (ArbitratorState, error) {
+	scopeBucket := tx.ReadBucket(b.scopeKey[:])
+	if scopeBucket == nil {
+		return 0, errScopeBucketNoExist
+	}
+
+	stateBytes := scopeBucket.Get(stateKey)
+	if stateBytes == nil {
+		return 0, nil
+	}
+
+	return ArbitratorState(stateBytes[0]), nil
+}
+
 // CommitState persists, the current state of the chain attendant.
 //
 // NOTE: Part of the ContractResolver interface.
@@ -851,29 +870,20 @@ func (b *boltArbitratorLog) InsertConfirmedCommitSet(c *CommitSet) error {
 }
 
 // FetchConfirmedCommitSet fetches the known confirmed active HTLC set from the
-// database.
+// database. It takes an optional database transaction, which will be used if it
+// is non-nil, otherwise the lookup will be done in its own transaction.
 //
 // NOTE: Part of the ContractResolver interface.
-func (b *boltArbitratorLog) FetchConfirmedCommitSet() (*CommitSet, error) {
+func (b *boltArbitratorLog) FetchConfirmedCommitSet(tx kvdb.RTx) (*CommitSet, error) {
+	if tx != nil {
+		return b.fetchConfirmedCommitSet(tx)
+	}
+
 	var c *CommitSet
 	err := kvdb.View(b.db, func(tx kvdb.RTx) error {
-		scopeBucket := tx.ReadBucket(b.scopeKey[:])
+		var err error
-		if scopeBucket == nil {
+		c, err = b.fetchConfirmedCommitSet(tx)
-			return errScopeBucketNoExist
+		return err
-		}
-
-		commitSetBytes := scopeBucket.Get(commitSetKey)
-		if commitSetBytes == nil {
-			return errNoCommitSet
-		}
-
-		commitSet, err := decodeCommitSet(bytes.NewReader(commitSetBytes))
-		if err != nil {
-			return err
-		}
-
-		c = commitSet
-		return nil
 	}, func() {
 		c = nil
 	})
@@ -884,6 +894,22 @@ func (b *boltArbitratorLog) FetchConfirmedCommitSet() (*CommitSet, error) {
 	return c, nil
 }
 
+func (b *boltArbitratorLog) fetchConfirmedCommitSet(tx kvdb.RTx) (*CommitSet,
+	error) {
+
+	scopeBucket := tx.ReadBucket(b.scopeKey[:])
+	if scopeBucket == nil {
+		return nil, errScopeBucketNoExist
+	}
+
+	commitSetBytes := scopeBucket.Get(commitSetKey)
+	if commitSetBytes == nil {
+		return nil, errNoCommitSet
+	}
+
+	return decodeCommitSet(bytes.NewReader(commitSetBytes))
+}
+
 // WipeHistory is to be called ONLY once *all* contracts have been fully
 // resolved, and the channel closure if finalized. This method will delete all
 // on-disk state within the persistent log.

contractcourt/briefcase_test.go

@@ -611,7 +611,7 @@ func TestStateMutation(t *testing.T) {
 	defer cleanUp()
 
 	// The default state of an arbitrator should be StateDefault.
-	arbState, err := testLog.CurrentState()
+	arbState, err := testLog.CurrentState(nil)
 	if err != nil {
 		t.Fatalf("unable to read arb state: %v", err)
 	}
@@ -625,7 +625,7 @@ func TestStateMutation(t *testing.T) {
 	if err := testLog.CommitState(StateFullyResolved); err != nil {
 		t.Fatalf("unable to write state: %v", err)
 	}
-	arbState, err = testLog.CurrentState()
+	arbState, err = testLog.CurrentState(nil)
 	if err != nil {
 		t.Fatalf("unable to read arb state: %v", err)
 	}
@@ -643,7 +643,7 @@ func TestStateMutation(t *testing.T) {
 
 	// If we try to query for the state again, we should get the default
 	// state again.
-	arbState, err = testLog.CurrentState()
+	arbState, err = testLog.CurrentState(nil)
 	if err != nil {
 		t.Fatalf("unable to query current state: %v", err)
 	}
@@ -687,11 +687,11 @@ func TestScopeIsolation(t *testing.T) {
 
 	// Querying each log, the states should be the prior one we set, and be
 	// disjoint.
-	log1State, err := testLog1.CurrentState()
+	log1State, err := testLog1.CurrentState(nil)
 	if err != nil {
 		t.Fatalf("unable to read arb state: %v", err)
 	}
-	log2State, err := testLog2.CurrentState()
+	log2State, err := testLog2.CurrentState(nil)
 	if err != nil {
 		t.Fatalf("unable to read arb state: %v", err)
 	}
@@ -752,7 +752,7 @@ func TestCommitSetStorage(t *testing.T) {
 				t.Fatalf("unable to write commit set: %v", err)
 			}
 
-			diskCommitSet, err := testLog.FetchConfirmedCommitSet()
+			diskCommitSet, err := testLog.FetchConfirmedCommitSet(nil)
 			if err != nil {
 				t.Fatalf("unable to read commit set: %v", err)
 			}

contractcourt/channel_arbitrator.go

@@ -398,7 +398,7 @@ func (c *ChannelArbitrator) Start() error {
 
 	// First, we'll read our last state from disk, so our internal state
 	// machine can act accordingly.
-	c.state, err = c.log.CurrentState()
+	c.state, err = c.log.CurrentState(nil)
 	if err != nil {
 		return err
 	}
@@ -454,7 +454,7 @@ func (c *ChannelArbitrator) Start() error {
 	// older nodes, this won't be found at all, and will rely on the
 	// existing written chain actions. Additionally, if this channel hasn't
 	// logged any actions in the log, then this field won't be present.
-	commitSet, err := c.log.FetchConfirmedCommitSet()
+	commitSet, err := c.log.FetchConfirmedCommitSet(nil)
 	if err != nil && err != errNoCommitSet && err != errScopeBucketNoExist {
 		return err
 	}

contractcourt/channel_arbitrator_test.go

@@ -51,7 +51,7 @@ type mockArbitratorLog struct {
 // interface.
 var _ ArbitratorLog = (*mockArbitratorLog)(nil)
 
-func (b *mockArbitratorLog) CurrentState() (ArbitratorState, error) {
+func (b *mockArbitratorLog) CurrentState(kvdb.RTx) (ArbitratorState, error) {
 	return b.state, nil
 }
 
@@ -140,7 +140,7 @@ func (b *mockArbitratorLog) InsertConfirmedCommitSet(c *CommitSet) error {
 	return nil
 }
 
-func (b *mockArbitratorLog) FetchConfirmedCommitSet() (*CommitSet, error) {
+func (b *mockArbitratorLog) FetchConfirmedCommitSet(kvdb.RTx) (*CommitSet, error) {
 	return b.commitSet, nil
 }