Merge pull request #723 from SiaFoundation/pj/wallet-redistribute

Wallet Redistribute

wallet/wallet.go

@@ -304,6 +304,34 @@ func (w *SingleAddressWallet) Redistribute(cs consensus.State, outputs int, amou
 	w.mu.Lock()
 	defer w.mu.Unlock()
 
+	// build map of inputs currently in the tx pool
+	inPool := make(map[types.Hash256]bool)
+	for _, ptxn := range pool {
+		for _, in := range ptxn.SiacoinInputs {
+			inPool[types.Hash256(in.ParentID)] = true
+		}
+	}
+
+	// fetch unspent transaction outputs
+	utxos, err := w.store.UnspentSiacoinElements(false)
+	if err != nil {
+		return types.Transaction{}, nil, err
+	}
+
+	// check whether a redistribution is necessary, adjust number of desired
+	// outputs accordingly
+	for _, sce := range utxos {
+		inUse := w.isOutputUsed(sce.ID) || inPool[sce.ID]
+		matured := cs.Index.Height >= sce.MaturityHeight
+		sameValue := sce.Value.Equals(amount)
+		if !inUse && matured && sameValue {
+			outputs--
+		}
+	}
+	if outputs <= 0 {
+		return types.Transaction{}, nil, nil
+	}
+
 	// prepare all outputs
 	var txn types.Transaction
 	for i := 0; i < int(outputs); i++ {
@@ -313,25 +341,11 @@ func (w *SingleAddressWallet) Redistribute(cs consensus.State, outputs int, amou
 		})
 	}
 
-	// fetch unspent transaction outputs
-	utxos, err := w.store.UnspentSiacoinElements(false)
-	if err != nil {
-		return types.Transaction{}, nil, err
-	}
-
 	// desc sort
 	sort.Slice(utxos, func(i, j int) bool {
 		return utxos[i].Value.Cmp(utxos[j].Value) > 0
 	})
 
-	// map used outputs
-	inPool := make(map[types.Hash256]bool)
-	for _, ptxn := range pool {
-		for _, in := range ptxn.SiacoinInputs {
-			inPool[types.Hash256(in.ParentID)] = true
-		}
-	}
-
 	// estimate the fees
 	outputFees := feePerByte.Mul64(uint64(len(encoding.Marshal(txn.SiacoinOutputs))))
 	feePerInput := feePerByte.Mul64(BytesPerInput)

wallet/wallet_test.go

@@ -112,7 +112,7 @@ func TestWalletRedistribute(t *testing.T) {
 
 	// split into 2 outputs of 9SC
 	amount = oneSC.Mul64(9)
-	if txn, _, err := w.Redistribute(cs, 2, oneSC.Mul64(9), types.NewCurrency64(1), nil); err != nil {
+	if txn, _, err := w.Redistribute(cs, 2, amount, types.NewCurrency64(1), nil); err != nil {
 		t.Fatal(err)
 	} else {
 		applyTxn(txn)
@@ -129,6 +129,36 @@ func TestWalletRedistribute(t *testing.T) {
 	if cnt := numOutputsWithValue(amount); cnt != 2 {
 		t.Fatalf("unexpected number of 9SC outputs, %v != 2", cnt)
 	}
+
+	// split into 5 outputs of 3SC
+	amount = oneSC.Mul64(3)
+	if txn, _, err := w.Redistribute(cs, 5, amount, types.NewCurrency64(1), nil); err != nil {
+		t.Fatal(err)
+	} else {
+		applyTxn(txn)
+	}
+
+	// assert number of outputs that hold 3SC
+	if cnt := numOutputsWithValue(amount); cnt != 5 {
+		t.Fatalf("unexpected number of 3SC outputs, %v != 5", cnt)
+	}
+
+	// split into 4 outputs of 3SC - this should be a no-op
+	if _, _, err := w.Redistribute(cs, 4, amount, types.NewCurrency64(1), nil); err != nil {
+		t.Fatal(err)
+	}
+
+	// split into 6 outputs of 3SC
+	if txn, _, err := w.Redistribute(cs, 6, amount, types.NewCurrency64(1), nil); err != nil {
+		t.Fatal(err)
+	} else {
+		applyTxn(txn)
+	}
+
+	// assert number of outputs that hold 3SC
+	if cnt := numOutputsWithValue(amount); cnt != 6 {
+		t.Fatalf("unexpected number of 3SC outputs, %v != 6", cnt)
+	}
 }
 
 func randomOutputID() (t types.Hash256) {