input: add constructor for csv-locked inputs

input/input.go

@@ -44,10 +44,11 @@ type Input interface {
 }
 
 type inputKit struct {
-	outpoint    wire.OutPoint
-	witnessType WitnessType
-	signDesc    SignDescriptor
-	heightHint  uint32
+	outpoint        wire.OutPoint
+	witnessType     WitnessType
+	signDesc        SignDescriptor
+	heightHint      uint32
+	blockToMaturity uint32
 }
 
 // OutPoint returns the breached output's identifier that is to be included as
@@ -74,6 +75,13 @@ func (i *inputKit) HeightHint() uint32 {
 	return i.heightHint
 }
 
+// BlocksToMaturity returns the relative timelock, as a number of blocks, that
+// must be built on top of the confirmation height before the output can be
+// spent. For non-CSV locked inputs this is always zero.
+func (i *inputKit) BlocksToMaturity() uint32 {
+	return i.blockToMaturity
+}
+
 // BaseInput contains all the information needed to sweep a basic output
 // (CSV/CLTV/no time lock)
 type BaseInput struct {
@@ -107,6 +115,23 @@ func NewBaseInput(outpoint *wire.OutPoint, witnessType WitnessType,
 	return &input
 }
 
+// NewCsvInput assembles a new csv-locked input that can be used to
+// construct a sweep transaction.
+func NewCsvInput(outpoint *wire.OutPoint, witnessType WitnessType,
+	signDescriptor *SignDescriptor, heightHint uint32,
+	blockToMaturity uint32) *BaseInput {
+
+	return &BaseInput{
+		inputKit{
+			outpoint:        *outpoint,
+			witnessType:     witnessType,
+			signDesc:        *signDescriptor,
+			heightHint:      heightHint,
+			blockToMaturity: blockToMaturity,
+		},
+	}
+}
+
 // CraftInputScript returns a valid set of input scripts allowing this output
 // to be spent. The returned input scripts should target the input at location
 // txIndex within the passed transaction. The input scripts generated by this
@@ -119,13 +144,6 @@ func (bi *BaseInput) CraftInputScript(signer Signer, txn *wire.MsgTx,
 	return witnessFunc(txn, hashCache, txinIdx)
 }
 
-// BlocksToMaturity returns the relative timelock, as a number of blocks, that
-// must be built on top of the confirmation height before the output can be
-// spent. For non-CSV locked inputs this is always zero.
-func (bi *BaseInput) BlocksToMaturity() uint32 {
-	return 0
-}
-
 // HtlcSucceedInput constitutes a sweep input that needs a pre-image. The input
 // is expected to reside on the commitment tx of the remote party and should
 // not be a second level tx output.
@@ -175,13 +193,6 @@ func (h *HtlcSucceedInput) CraftInputScript(signer Signer, txn *wire.MsgTx,
 	}, nil
 }
 
-// BlocksToMaturity returns the relative timelock, as a number of blocks, that
-// must be built on top of the confirmation height before the output can be
-// spent.
-func (h *HtlcSucceedInput) BlocksToMaturity() uint32 {
-	return 0
-}
-
 // Compile-time constraints to ensure each input struct implement the Input
 // interface.
 var _ Input = (*BaseInput)(nil)