Ledger integration (#931)

Merges the keybase and Ledger code from go-crypto (which is no more) into the SDK
Adds support for Ledger into gaiacli
Cherry-picks updated error handling from #1158

client/context/helpers.go

@@ -126,7 +126,7 @@ func (ctx CoreContext) GetFromAddress() (from sdk.Address, err error) {
 		return nil, errors.Errorf("no key for: %s", name)
 	}
 
-	return info.PubKey.Address(), nil
+	return info.GetPubKey().Address(), nil
 }
 
 // sign and build the transaction from the msg
@@ -187,15 +187,29 @@ func (ctx CoreContext) ensureSignBuild(name string, msgs []sdk.Msg, cdc *wire.Co
 		return nil, err
 	}
 
-	passphrase, err := ctx.GetPassphraseFromStdin(name)
+	var txBytes []byte
+
+	keybase, err := keys.GetKeyBase()
 	if err != nil {
 		return nil, err
 	}
 
-	txBytes, err := ctx.SignAndBuild(name, passphrase, msgs, cdc)
+	info, err := keybase.Get(name)
 	if err != nil {
 		return nil, err
 	}
+	var passphrase string
+	// Only need a passphrase for locally-stored keys
+	if info.GetType() == "local" {
+		passphrase, err = ctx.GetPassphraseFromStdin(name)
+		if err != nil {
+			return nil, fmt.Errorf("Error fetching passphrase: %v", err)
+		}
+	}
+	txBytes, err = ctx.SignAndBuild(name, passphrase, msgs, cdc)
+	if err != nil {
+		return nil, fmt.Errorf("Error signing transaction: %v", err)
+	}
 
 	return txBytes, err
 }

client/context/types.go

@@ -20,6 +20,7 @@ type CoreContext struct {
 	Client          rpcclient.Client
 	Decoder         auth.AccountDecoder
 	AccountStore    string
+	UseLedger       bool
 }
 
 // WithChainID - return a copy of the context with an updated chainID
@@ -94,3 +95,9 @@ func (c CoreContext) WithAccountStore(accountStore string) CoreContext {
 	c.AccountStore = accountStore
 	return c
 }
+
+// WithUseLedger - return a copy of the context with an updated UseLedger
+func (c CoreContext) WithUseLedger(useLedger bool) CoreContext {
+	c.UseLedger = useLedger
+	return c
+}

client/context/viper.go

@@ -40,6 +40,7 @@ func NewCoreContextFromViper() CoreContext {
 		Client:          rpc,
 		Decoder:         nil,
 		AccountStore:    "acc",
+		UseLedger:       viper.GetBool(client.FlagUseLedger),
 	}
 }