Merge PR #3159: Add address interface

* Add address interface
* Add test for addresses
* Address comments

PENDING.md

@@ -61,6 +61,7 @@ IMPROVEMENTS
 * Gaia CLI  (`gaiacli`)
 
 * Gaia
+  * [\#2186](https://github.com/cosmos/cosmos-sdk/issues/2186) Add Address Interface
   * [\#3158](https://github.com/cosmos/cosmos-sdk/pull/3158) Validate slashing genesis
   * [\#3172](https://github.com/cosmos/cosmos-sdk/pull/3172) Support minimum fees
   in a local testnet.

types/address.go

@@ -31,6 +31,22 @@ const (
 	Bech32PrefixConsPub = "cosmosvalconspub"
 )
 
+// Address is a common interface for different types of addresses used by the SDK
+type Address interface {
+	Equals(Address) bool
+	Empty() bool
+	Marshal() ([]byte, error)
+	MarshalJSON() ([]byte, error)
+	Bytes() []byte
+	String() string
+	Format(s fmt.State, verb rune)
+}
+
+// Ensure that different address types implement the interface
+var _ Address = AccAddress{}
+var _ Address = ValAddress{}
+var _ Address = ConsAddress{}
+
 // ----------------------------------------------------------------------------
 // account
 // ----------------------------------------------------------------------------
@@ -65,7 +81,7 @@ func AccAddressFromBech32(address string) (addr AccAddress, err error) {
 }
 
 // Returns boolean for whether two AccAddresses are Equal
-func (aa AccAddress) Equals(aa2 AccAddress) bool {
+func (aa AccAddress) Equals(aa2 Address) bool {
 	if aa.Empty() && aa2.Empty() {
 		return true
 	}
@@ -181,7 +197,7 @@ func ValAddressFromBech32(address string) (addr ValAddress, err error) {
 }
 
 // Returns boolean for whether two ValAddresses are Equal
-func (va ValAddress) Equals(va2 ValAddress) bool {
+func (va ValAddress) Equals(va2 Address) bool {
 	if va.Empty() && va2.Empty() {
 		return true
 	}
@@ -303,7 +319,7 @@ func GetConsAddress(pubkey crypto.PubKey) ConsAddress {
 }
 
 // Returns boolean for whether two ConsAddress are Equal
-func (ca ConsAddress) Equals(ca2 ConsAddress) bool {
+func (ca ConsAddress) Equals(ca2 Address) bool {
 	if ca.Empty() && ca2.Empty() {
 		return true
 	}

types/address_test.go

@@ -221,3 +221,31 @@ func TestConfiguredPrefix(t *testing.T) {
 
 	}
 }
+
+func TestAddressInterface(t *testing.T) {
+	var pub ed25519.PubKeyEd25519
+	rand.Read(pub[:])
+
+	addrs := []types.Address{
+		types.ConsAddress(pub.Address()),
+		types.ValAddress(pub.Address()),
+		types.AccAddress(pub.Address()),
+	}
+
+	for _, addr := range addrs {
+		switch addr := addr.(type) {
+		case types.AccAddress:
+			_, err := types.AccAddressFromBech32(addr.String())
+			require.Nil(t, err)
+		case types.ValAddress:
+			_, err := types.ValAddressFromBech32(addr.String())
+			require.Nil(t, err)
+		case types.ConsAddress:
+			_, err := types.ConsAddressFromBech32(addr.String())
+			require.Nil(t, err)
+		default:
+			t.Fail()
+		}
+	}
+
+}