Make AddressInfo an interface.

Shortly we will add new types of address, so make AddressInfo an
interface, with concrete types providing address-specific information.
Adapt existing code to this new status quo.

account.go

@@ -315,7 +315,7 @@ func (a *Account) DumpPrivKeys() ([]string, error) {
 			return nil, err
 		}
 		encKey, err := btcutil.EncodePrivateKey(key.D.Bytes(),
-			a.Wallet.Net(), info.Compressed)
+			a.Wallet.Net(), info.Compressed())
 		if err != nil {
 			return nil, err
 		}
@@ -342,7 +342,8 @@ func (a *Account) DumpWIFPrivateKey(addr btcutil.Address) (string, error) {
 	}
 
 	// Return WIF-encoding of the private key.
-	return btcutil.EncodePrivateKey(key.D.Bytes(), a.Net(), info.Compressed)
+	return btcutil.EncodePrivateKey(key.D.Bytes(), a.Net(),
+		info.Compressed())
 }
 
 // ImportPrivateKey imports a private key to the account's wallet and
@@ -497,7 +498,7 @@ func (a *Account) SortedActivePaymentAddresses() []string {
 
 	addrs := make([]string, len(infos))
 	for i, info := range infos {
-		addrs[i] = info.Address.EncodeAddress()
+		addrs[i] = info.Address().EncodeAddress()
 	}
 
 	return addrs
@@ -510,7 +511,7 @@ func (a *Account) ActivePaymentAddresses() map[string]struct{} {
 
 	addrs := make(map[string]struct{}, len(infos))
 	for _, info := range infos {
-		addrs[info.Address.EncodeAddress()] = struct{}{}
+		addrs[info.Address().EncodeAddress()] = struct{}{}
 	}
 
 	return addrs
@@ -595,7 +596,7 @@ func (a *Account) RecoverAddresses(n int) error {
 		m[addrs[i].EncodeAddress()] = struct{}{}
 	}
 	go func(addrs map[string]struct{}) {
-		jsonErr := Rescan(CurrentServerConn(), lastInfo.FirstBlock, addrs)
+		jsonErr := Rescan(CurrentServerConn(), lastInfo.FirstBlock(), addrs)
 		if jsonErr != nil {
 			log.Errorf("Rescanning for recovered addresses failed: %v",
 				jsonErr.Message)

createtx.go

@@ -257,7 +257,7 @@ func (a *Account) txToPairs(pairs map[string]int64, minconf int) (*CreatedTx, er
 
 			sigscript, err := btcscript.SignatureScript(msgtx, i,
 				input.PkScript(), btcscript.SigHashAll, privkey,
-				ai.Compressed)
+				ai.Compressed())
 			if err != nil {
 				return nil, fmt.Errorf("cannot create sigscript: %s", err)
 			}

rpcserver.go

@@ -1493,7 +1493,7 @@ func SignMessage(icmd btcjson.Cmd) (interface{}, *btcjson.Error) {
 
 	fullmsg := "Bitcoin Signed Message:\n" + cmd.Message
 	sigbytes, err := btcec.SignCompact(btcec.S256(), privkey,
-		btcwire.DoubleSha256([]byte(fullmsg)), ainfo.Compressed)
+		btcwire.DoubleSha256([]byte(fullmsg)), ainfo.Compressed())
 	if err != nil {
 		return nil, &btcjson.Error{
 			Code:    btcjson.ErrWallet.Code,
@@ -1600,13 +1600,18 @@ func ValidateAddress(icmd btcjson.Cmd) (interface{}, *btcjson.Error) {
 		result["ismine"] = true
 		result["account"] = account
 
+		switch info := ainfo.(type) {
+		case *wallet.AddressPubKeyInfo:
+			result["compressed"] = info.Compressed()
+			result["pubkey"] = info.Pubkey
+		default:
+		}
+
 		// TODO(oga) when we handle different types of addresses then
 		// we will need to check here and only provide the script,
 		// hexsript and list of addresses.
 		// if scripthash, the pubkey if pubkey/pubkeyhash, etc.
 		// for now we only support p2pkh so is irrelavent
-		result["compressed"] = ainfo.Compressed
-		result["pubkey"] = ainfo.Pubkey
 	} else {
 		result["ismine"] = false
 	}
@@ -1681,7 +1686,7 @@ func VerifyMessage(icmd btcjson.Cmd) (interface{}, *btcjson.Error) {
 
 	// Return boolean if keys match.
 	return (pk.X.Cmp(privkey.X) == 0 && pk.Y.Cmp(privkey.Y) == 0 &&
-		ainfo.Compressed == wasCompressed), nil
+		ainfo.Compressed() == wasCompressed), nil
 }
 
 // WalletIsLocked handles the walletislocked extension request by

wallet/wallet.go

@@ -1165,7 +1165,7 @@ func (w *Wallet) AddressKey(a btcutil.Address) (key *ecdsa.PrivateKey, err error
 }
 
 // AddressInfo returns an AddressInfo structure for an address in a wallet.
-func (w *Wallet) AddressInfo(a btcutil.Address) (*AddressInfo, error) {
+func (w *Wallet) AddressInfo(a btcutil.Address) (AddressInfo, error) {
 	// Currently, only P2PKH addresses are supported.  This should
 	// be extended to a switch-case statement when support for other
 	// addresses are added.
@@ -1404,24 +1404,77 @@ func (w *Wallet) ExportWatchingWallet() (*Wallet, error) {
 	return ww, nil
 }
 
-// AddressInfo holds information regarding an address needed to manage
-// a complete wallet.
-type AddressInfo struct {
-	btcutil.Address
-	AddrHash   string
-	Compressed bool
-	FirstBlock int32
-	Imported   bool
+// AddressInfo is an interface that provides acces to information regarding an
+// address managed by a wallet. Concrete implementations of this type may
+// provide further fields to provide information specific to that type of
+// address.
+type AddressInfo interface {
+	// Address returns a btcutil.Address for the backing address.
+	Address() btcutil.Address
+	// FirstBlock returns the first block an address could be in.
+	FirstBlock() int32
+	// Compressed returns true if the backing address was imported instead
+	// of being part of an address chain.
+	Imported() bool
+	// Compressed returns true if the backing address was created for a
+	// change output of a transaction.
+	Change() bool
+	// Compressed returns true if the backing address is compressed.
+	Compressed() bool
+}
+
+// AddressPubKeyInfo implements AddressInfo and additionally provides the
+// pubkey for a pubkey-based address.
+type AddressPubKeyInfo struct {
+	address    btcutil.Address
+	addrHash   string
+	compressed bool
+	firstBlock int32
+	imported   bool
 	Pubkey     string
-	Change     bool
+	change     bool
+}
+
+// Address returns the pub key address, implementing AddressInfo.
+func (ai *AddressPubKeyInfo) Address() btcutil.Address {
+	return ai.address
+}
+
+// AddrHash returns the pub key hash, implementing AddressInfo.
+func (ai *AddressPubKeyInfo) AddrHash() string {
+	return ai.addrHash
+}
+
+// FirstBlock returns the first block the address is seen in, implementing
+// AddressInfo.
+func (ai *AddressPubKeyInfo) FirstBlock() int32 {
+	return ai.firstBlock
+}
+
+// Imported returns the pub if the address was imported, or a chained address,
+// implementing AddressInfo.
+func (ai *AddressPubKeyInfo) Imported() bool {
+	return ai.imported
+}
+
+// AddrHash returns true if the address was created as a change address,
+// implementing AddressInfo.
+func (ai *AddressPubKeyInfo) Change() bool {
+	return ai.change
+}
+
+// AddrHash returns true if the address backing key is compressed,
+// implementing AddressInfo.
+func (ai *AddressPubKeyInfo) Compressed() bool {
+	return ai.compressed
 }
 
 // SortedActiveAddresses returns all wallet addresses that have been
 // requested to be generated.  These do not include unused addresses in
 // the key pool.  Use this when ordered addresses are needed.  Otherwise,
 // ActiveAddresses is preferred.
-func (w *Wallet) SortedActiveAddresses() []*AddressInfo {
-	addrs := make([]*AddressInfo, 0,
+func (w *Wallet) SortedActiveAddresses() []AddressInfo {
+	addrs := make([]AddressInfo, 0,
 		w.highestUsed+int64(len(w.importedAddrs))+1)
 	for i := int64(rootKeyChainIdx); i <= w.highestUsed; i++ {
 		a := w.chainIdxMap[i]
@@ -1442,19 +1495,19 @@ func (w *Wallet) SortedActiveAddresses() []*AddressInfo {
 // ActiveAddresses returns a map between active payment addresses
 // and their full info.  These do not include unused addresses in the
 // key pool.  If addresses must be sorted, use SortedActiveAddresses.
-func (w *Wallet) ActiveAddresses() map[btcutil.Address]*AddressInfo {
-	addrs := make(map[btcutil.Address]*AddressInfo)
+func (w *Wallet) ActiveAddresses() map[btcutil.Address]AddressInfo {
+	addrs := make(map[btcutil.Address]AddressInfo)
 	for i := int64(rootKeyChainIdx); i <= w.highestUsed; i++ {
 		a := w.chainIdxMap[i]
 		info, err := w.addrMap[*a].info(w.Net())
 		if err == nil {
-			addrs[info.Address] = info
+			addrs[info.Address()] = info
 		}
 	}
 	for _, addr := range w.importedAddrs {
 		info, err := addr.info(w.Net())
 		if err == nil {
-			addrs[info.Address] = info
+			addrs[info.Address()] = info
 		}
 	}
 	return addrs
@@ -2273,17 +2326,17 @@ func (a *btcAddress) address(net btcwire.BitcoinNet) *btcutil.AddressPubKeyHash
 
 // info returns information about a btcAddress stored in a AddressInfo
 // struct.
-func (a *btcAddress) info(net btcwire.BitcoinNet) (*AddressInfo, error) {
+func (a *btcAddress) info(net btcwire.BitcoinNet) (AddressInfo, error) {
 	address := a.address(net)
 
-	return &AddressInfo{
-		Address:    address,
-		AddrHash:   string(a.pubKeyHash[:]),
-		Compressed: a.flags.compressed,
-		FirstBlock: a.firstBlock,
-		Imported:   a.chainIndex == importedKeyChainIdx,
+	return &AddressPubKeyInfo{
+		address:    address,
+		addrHash:   string(a.pubKeyHash[:]),
+		compressed: a.flags.compressed,
+		firstBlock: a.firstBlock,
+		imported:   a.chainIndex == importedKeyChainIdx,
 		Pubkey:     hex.EncodeToString(a.pubKey),
-		Change:     a.flags.change,
+		change:     a.flags.change,
 	}, nil
 }
 

wallet/wallet_test.go

@@ -347,12 +347,14 @@ func TestWalletPubkeyChaining(t *testing.T) {
 		t.Errorf("Failed to get info about address without private key: %v", err)
 		return
 	}
+
+	pkinfo := info.(*AddressPubKeyInfo)
 	// sanity checks
-	if !info.Compressed {
+	if !info.Compressed() {
 		t.Errorf("Pubkey should be compressed.")
 		return
 	}
-	if info.Imported {
+	if info.Imported() {
 		t.Errorf("Should not be marked as imported.")
 		return
 	}
@@ -419,7 +421,7 @@ func TestWalletPubkeyChaining(t *testing.T) {
 		t.Errorf("Unable to sign hash with the created private key: %v", err)
 		return
 	}
-	pubKeyStr, _ := hex.DecodeString(info.Pubkey)
+	pubKeyStr, _ := hex.DecodeString(pkinfo.Pubkey)
 	pubKey, err := btcec.ParsePubKey(pubKeyStr, btcec.S256())
 	ok := ecdsa.Verify(pubKey, hash, r, s)
 	if !ok {
@@ -442,6 +444,7 @@ func TestWalletPubkeyChaining(t *testing.T) {
 		t.Errorf("Couldn't get info about the next address in the chain: %v", err)
 		return
 	}
+	nextPkInfo := nextInfo.(*AddressPubKeyInfo)
 	nextKey, err := w.AddressKey(nextAddr)
 	if err != nil {
 		t.Errorf("Couldn't get private key for the next address in the chain: %v", err)
@@ -455,7 +458,7 @@ func TestWalletPubkeyChaining(t *testing.T) {
 		t.Errorf("Unable to sign hash with the created private key: %v", err)
 		return
 	}
-	pubKeyStr, _ = hex.DecodeString(nextInfo.Pubkey)
+	pubKeyStr, _ = hex.DecodeString(nextPkInfo.Pubkey)
 	pubKey, err = btcec.ParsePubKey(pubKeyStr, btcec.S256())
 	ok = ecdsa.Verify(pubKey, hash, r, s)
 	if !ok {