rpcclient: implement gettxoutsetinfo command

btcjson/chainsvrresults.go

@@ -9,6 +9,8 @@ import (
 	"encoding/hex"
 	"encoding/json"
 
+	"github.com/btcsuite/btcd/chaincfg/chainhash"
+
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcutil"
 )
@@ -435,6 +437,64 @@ type GetTxOutResult struct {
 	Coinbase      bool               `json:"coinbase"`
 }
 
+// GetTxOutSetInfoResult models the data from the gettxoutsetinfo command.
+type GetTxOutSetInfoResult struct {
+	Height         int64          `json:"height"`
+	BestBlock      chainhash.Hash `json:"bestblock"`
+	Transactions   int64          `json:"transactions"`
+	TxOuts         int64          `json:"txouts"`
+	BogoSize       int64          `json:"bogosize"`
+	HashSerialized chainhash.Hash `json:"hash_serialized_2"`
+	DiskSize       int64          `json:"disk_size"`
+	TotalAmount    btcutil.Amount `json:"total_amount"`
+}
+
+// UnmarshalJSON unmarshals the result of the gettxoutsetinfo JSON-RPC call
+func (g *GetTxOutSetInfoResult) UnmarshalJSON(data []byte) error {
+	// Step 1: Create type aliases of the original struct.
+	type Alias GetTxOutSetInfoResult
+
+	// Step 2: Create an anonymous struct with raw replacements for the special
+	// fields.
+	aux := &struct {
+		BestBlock      string  `json:"bestblock"`
+		HashSerialized string  `json:"hash_serialized_2"`
+		TotalAmount    float64 `json:"total_amount"`
+		*Alias
+	}{
+		Alias: (*Alias)(g),
+	}
+
+	// Step 3: Unmarshal the data into the anonymous struct.
+	if err := json.Unmarshal(data, &aux); err != nil {
+		return err
+	}
+
+	// Step 4: Convert the raw fields to the desired types
+	blockHash, err := chainhash.NewHashFromStr(aux.BestBlock)
+	if err != nil {
+		return err
+	}
+
+	g.BestBlock = *blockHash
+
+	serializedHash, err := chainhash.NewHashFromStr(aux.HashSerialized)
+	if err != nil {
+		return err
+	}
+
+	g.HashSerialized = *serializedHash
+
+	amount, err := btcutil.NewAmount(aux.TotalAmount)
+	if err != nil {
+		return err
+	}
+
+	g.TotalAmount = amount
+
+	return nil
+}
+
 // GetNetTotalsResult models the data returned from the getnettotals command.
 type GetNetTotalsResult struct {
 	TotalBytesRecv uint64 `json:"totalbytesrecv"`

btcjson/chainsvrresults_test.go

@@ -6,8 +6,13 @@ package btcjson_test
 
 import (
 	"encoding/json"
+	"reflect"
 	"testing"
 
+	"github.com/btcsuite/btcd/chaincfg/chainhash"
+	"github.com/btcsuite/btcutil"
+	"github.com/davecgh/go-spew/spew"
+
 	"github.com/btcsuite/btcd/btcjson"
 )
 
@@ -86,3 +91,69 @@ func TestChainSvrCustomResults(t *testing.T) {
 		}
 	}
 }
+
+// TestGetTxOutSetInfoResult ensures that custom unmarshalling of
+// GetTxOutSetInfoResult works as intended.
+func TestGetTxOutSetInfoResult(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name   string
+		result string
+		want   btcjson.GetTxOutSetInfoResult
+	}{
+		{
+			name:   "GetTxOutSetInfoResult - not scanning",
+			result: `{"height":123,"bestblock":"000000000000005f94116250e2407310463c0a7cf950f1af9ebe935b1c0687ab","transactions":1,"txouts":1,"bogosize":1,"hash_serialized_2":"9a0a561203ff052182993bc5d0cb2c620880bfafdbd80331f65fd9546c3e5c3e","disk_size":1,"total_amount":0.2}`,
+			want: btcjson.GetTxOutSetInfoResult{
+				Height: 123,
+				BestBlock: func() chainhash.Hash {
+					h, err := chainhash.NewHashFromStr("000000000000005f94116250e2407310463c0a7cf950f1af9ebe935b1c0687ab")
+					if err != nil {
+						panic(err)
+					}
+
+					return *h
+				}(),
+				Transactions: 1,
+				TxOuts:       1,
+				BogoSize:     1,
+				HashSerialized: func() chainhash.Hash {
+					h, err := chainhash.NewHashFromStr("9a0a561203ff052182993bc5d0cb2c620880bfafdbd80331f65fd9546c3e5c3e")
+					if err != nil {
+						panic(err)
+					}
+
+					return *h
+				}(),
+				DiskSize: 1,
+				TotalAmount: func() btcutil.Amount {
+					a, err := btcutil.NewAmount(0.2)
+					if err != nil {
+						panic(err)
+					}
+
+					return a
+				}(),
+			},
+		},
+	}
+
+	t.Logf("Running %d tests", len(tests))
+	for i, test := range tests {
+		var out btcjson.GetTxOutSetInfoResult
+		err := json.Unmarshal([]byte(test.result), &out)
+		if err != nil {
+			t.Errorf("Test #%d (%s) unexpected error: %v", i,
+				test.name, err)
+			continue
+		}
+
+		if !reflect.DeepEqual(out, test.want) {
+			t.Errorf("Test #%d (%s) unexpected unmarshalled data - "+
+				"got %v, want %v", i, test.name, spew.Sdump(out),
+				spew.Sdump(test.want))
+			continue
+		}
+	}
+}

rpcclient/chain.go

@@ -1026,6 +1026,44 @@ func (c *Client) GetTxOut(txHash *chainhash.Hash, index uint32, mempool bool) (*
 	return c.GetTxOutAsync(txHash, index, mempool).Receive()
 }
 
+// FutureGetTxOutSetInfoResult is a future promise to deliver the result of a
+// GetTxOutSetInfoAsync RPC invocation (or an applicable error).
+type FutureGetTxOutSetInfoResult chan *response
+
+// Receive waits for the response promised by the future and returns the
+// results of GetTxOutSetInfoAsync RPC invocation.
+func (r FutureGetTxOutSetInfoResult) Receive() (*btcjson.GetTxOutSetInfoResult, error) {
+	res, err := receiveFuture(r)
+	if err != nil {
+		return nil, err
+	}
+
+	// Unmarshal result as an gettxoutsetinfo result object.
+	var txOutSetInfo *btcjson.GetTxOutSetInfoResult
+	err = json.Unmarshal(res, &txOutSetInfo)
+	if err != nil {
+		return nil, err
+	}
+
+	return txOutSetInfo, nil
+}
+
+// GetTxOutSetInfoAsync returns an instance of a type that can be used to get
+// the result of the RPC at some future time by invoking the Receive function on
+// the returned instance.
+//
+// See GetTxOutSetInfo for the blocking version and more details.
+func (c *Client) GetTxOutSetInfoAsync() FutureGetTxOutSetInfoResult {
+	cmd := btcjson.NewGetTxOutSetInfoCmd()
+	return c.sendCmd(cmd)
+}
+
+// GetTxOutSetInfo returns the statistics about the unspent transaction output
+// set.
+func (c *Client) GetTxOutSetInfo() (*btcjson.GetTxOutSetInfoResult, error) {
+	return c.GetTxOutSetInfoAsync().Receive()
+}
+
 // FutureRescanBlocksResult is a future promise to deliver the result of a
 // RescanBlocksAsync RPC invocation (or an applicable error).
 //

rpcclient/example_test.go

@@ -116,3 +116,22 @@ func ExampleClient_GetWalletInfo() {
 	fmt.Println(*info.HDSeedID)        // eb44e4e9b864ef17e7ba947da746375b000f5d94
 	fmt.Println(info.Scanning.Value)   // false
 }
+
+func ExampleClient_GetTxOutSetInfo() {
+	client, err := New(connCfg, nil)
+	if err != nil {
+		panic(err)
+	}
+	defer client.Shutdown()
+
+	r, err := client.GetTxOutSetInfo()
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Println(r.TotalAmount.String()) // 20947654.56996054 BTC
+	fmt.Println(r.BestBlock.String())   // 000000000000005f94116250e2407310463c0a7cf950f1af9ebe935b1c0687ab
+	fmt.Println(r.TxOuts)               // 24280607
+	fmt.Println(r.Transactions)         // 9285603
+	fmt.Println(r.DiskSize)             // 1320871611
+}