mobile: iOS naming and API fixes for generators and Swift (ethereum#3408)

* build: modify the iOS namespace to iGeth (gomobile limitation)
* mobile: assign names to return types for ObjC wrapper
* mobile: use more expanded names for iOS/Swift API

Author: karalabe

build/ci.go

@@ -800,7 +800,7 @@ func doXCodeFramework(cmdline []string) {
 	// Build the iOS XCode framework
 	build.MustRun(goTool("get", "golang.org/x/mobile/cmd/gomobile"))
 	build.MustRun(gomobileTool("init"))
-	bind := gomobileTool("bind", "--target", "ios", "--tags", "ios", "--prefix", "GE", "-v", "github.com/ethereum/go-ethereum/mobile")
+	bind := gomobileTool("bind", "--target", "ios", "--tags", "ios", "--prefix", "i", "-v", "github.com/ethereum/go-ethereum/mobile")
 
 	if *local {
 		// If we're building locally, use the build folder and stop afterwards

mobile/accounts.go

@@ -56,7 +56,7 @@ func (a *Accounts) Size() int {
 }
 
 // Get returns the account at the given index from the slice.
-func (a *Accounts) Get(index int) (*Account, error) {
+func (a *Accounts) Get(index int) (account *Account, _ error) {
 	if index < 0 || index >= len(a.accounts) {
 		return nil, errors.New("index out of bounds")
 	}
@@ -91,8 +91,8 @@ func NewAccountManager(keydir string, scryptN, scryptP int) *AccountManager {
 }
 
 // HasAddress reports whether a key with the given address is present.
-func (am *AccountManager) HasAddress(addr *Address) bool {
-	return am.manager.HasAddress(addr.address)
+func (am *AccountManager) HasAddress(address *Address) bool {
+	return am.manager.HasAddress(address.address)
 }
 
 // GetAccounts returns all key files present in the directory.
@@ -102,32 +102,32 @@ func (am *AccountManager) GetAccounts() *Accounts {
 
 // DeleteAccount deletes the key matched by account if the passphrase is correct.
 // If a contains no filename, the address must match a unique key.
-func (am *AccountManager) DeleteAccount(a *Account, passphrase string) error {
+func (am *AccountManager) DeleteAccount(account *Account, passphrase string) error {
 	return am.manager.DeleteAccount(accounts.Account{
-		Address: a.account.Address,
-		File:    a.account.File,
+		Address: account.account.Address,
+		File:    account.account.File,
 	}, passphrase)
 }
 
 // Sign signs hash with an unlocked private key matching the given address.
-func (am *AccountManager) Sign(addr *Address, hash []byte) ([]byte, error) {
-	return am.manager.Sign(addr.address, hash)
+func (am *AccountManager) Sign(address *Address, hash []byte) (signature []byte, _ error) {
+	return am.manager.Sign(address.address, hash)
 }
 
 // SignWithPassphrase signs hash if the private key matching the given address can be
 // decrypted with the given passphrase.
-func (am *AccountManager) SignWithPassphrase(addr *Address, passphrase string, hash []byte) ([]byte, error) {
-	return am.manager.SignWithPassphrase(addr.address, passphrase, hash)
+func (am *AccountManager) SignWithPassphrase(address *Address, passphrase string, hash []byte) (signature []byte, _ error) {
+	return am.manager.SignWithPassphrase(address.address, passphrase, hash)
 }
 
 // Unlock unlocks the given account indefinitely.
-func (am *AccountManager) Unlock(a *Account, passphrase string) error {
-	return am.manager.TimedUnlock(a.account, passphrase, 0)
+func (am *AccountManager) Unlock(account *Account, passphrase string) error {
+	return am.manager.TimedUnlock(account.account, passphrase, 0)
 }
 
 // Lock removes the private key with the given address from memory.
-func (am *AccountManager) Lock(addr *Address) error {
-	return am.manager.Lock(addr.address)
+func (am *AccountManager) Lock(address *Address) error {
+	return am.manager.Lock(address.address)
 }
 
 // TimedUnlock unlocks the given account with the passphrase. The account
@@ -152,27 +152,27 @@ func (am *AccountManager) NewAccount(passphrase string) (*Account, error) {
 }
 
 // ExportKey exports as a JSON key, encrypted with newPassphrase.
-func (am *AccountManager) ExportKey(a *Account, passphrase, newPassphrase string) ([]byte, error) {
-	return am.manager.Export(a.account, passphrase, newPassphrase)
+func (am *AccountManager) ExportKey(account *Account, passphrase, newPassphrase string) (key []byte, _ error) {
+	return am.manager.Export(account.account, passphrase, newPassphrase)
 }
 
 // ImportKey stores the given encrypted JSON key into the key directory.
-func (am *AccountManager) ImportKey(keyJSON []byte, passphrase, newPassphrase string) (*Account, error) {
-	account, err := am.manager.Import(keyJSON, passphrase, newPassphrase)
+func (am *AccountManager) ImportKey(keyJSON []byte, passphrase, newPassphrase string) (account *Account, _ error) {
+	acc, err := am.manager.Import(keyJSON, passphrase, newPassphrase)
 	if err != nil {
 		return nil, err
 	}
-	return &Account{account}, nil
+	return &Account{acc}, nil
 }
 
 // Update changes the passphrase of an existing account.
-func (am *AccountManager) Update(a *Account, passphrase, newPassphrase string) error {
-	return am.manager.Update(a.account, passphrase, newPassphrase)
+func (am *AccountManager) Update(account *Account, passphrase, newPassphrase string) error {
+	return am.manager.Update(account.account, passphrase, newPassphrase)
 }
 
 // ImportPreSaleKey decrypts the given Ethereum presale wallet and stores
 // a key file in the key directory. The key file is encrypted with the same passphrase.
-func (am *AccountManager) ImportPreSaleKey(keyJSON []byte, passphrase string) (*Account, error) {
+func (am *AccountManager) ImportPreSaleKey(keyJSON []byte, passphrase string) (ccount *Account, _ error) {
 	account, err := am.manager.ImportPreSaleKey(keyJSON, passphrase)
 	if err != nil {
 		return nil, err

mobile/big.go

@@ -78,7 +78,7 @@ func (bi *BigInts) Size() int {
 }
 
 // Get returns the bigint at the given index from the slice.
-func (bi *BigInts) Get(index int) (*BigInt, error) {
+func (bi *BigInts) Get(index int) (bigint *BigInt, _ error) {
 	if index < 0 || index >= len(bi.bigints) {
 		return nil, errors.New("index out of bounds")
 	}

mobile/bind.go

@@ -31,15 +31,15 @@ import (
 // Signer is an interaface defining the callback when a contract requires a
 // method to sign the transaction before submission.
 type Signer interface {
-	Sign(*Address, *Transaction) (*Transaction, error)
+	Sign(*Address, *Transaction) (tx *Transaction, _ error)
 }
 
 type signer struct {
 	sign bind.SignerFn
 }
 
-func (s *signer) Sign(addr *Address, tx *Transaction) (*Transaction, error) {
-	sig, err := s.sign(types.HomesteadSigner{}, addr.address, tx.tx)
+func (s *signer) Sign(addr *Address, unsignedTx *Transaction) (signedTx *Transaction, _ error) {
+	sig, err := s.sign(types.HomesteadSigner{}, addr.address, unsignedTx.tx)
 	if err != nil {
 		return nil, err
 	}
@@ -113,7 +113,7 @@ type BoundContract struct {
 
 // DeployContract deploys a contract onto the Ethereum blockchain and binds the
 // deployment address with a wrapper.
-func DeployContract(opts *TransactOpts, abiJSON string, bytecode []byte, client *EthereumClient, args *Interfaces) (*BoundContract, error) {
+func DeployContract(opts *TransactOpts, abiJSON string, bytecode []byte, client *EthereumClient, args *Interfaces) (contract *BoundContract, _ error) {
 	// Convert all the deployment parameters to Go types
 	params := make([]interface{}, len(args.objects))
 	for i, obj := range args.objects {
@@ -137,7 +137,7 @@ func DeployContract(opts *TransactOpts, abiJSON string, bytecode []byte, client
 
 // BindContract creates a low level contract interface through which calls and
 // transactions may be made through.
-func BindContract(address *Address, abiJSON string, client *EthereumClient) (*BoundContract, error) {
+func BindContract(address *Address, abiJSON string, client *EthereumClient) (contract *BoundContract, _ error) {
 	parsed, err := abi.JSON(strings.NewReader(abiJSON))
 	if err != nil {
 		return nil, err
@@ -179,24 +179,24 @@ func (c *BoundContract) Call(opts *CallOpts, out *Interfaces, method string, arg
 }
 
 // Transact invokes the (paid) contract method with params as input values.
-func (c *BoundContract) Transact(opts *TransactOpts, method string, args *Interfaces) (*Transaction, error) {
+func (c *BoundContract) Transact(opts *TransactOpts, method string, args *Interfaces) (tx *Transaction, _ error) {
 	params := make([]interface{}, len(args.objects))
 	for i, obj := range args.objects {
 		params[i] = obj
 	}
-	tx, err := c.contract.Transact(&opts.opts, method, params)
+	rawTx, err := c.contract.Transact(&opts.opts, method, params)
 	if err != nil {
 		return nil, err
 	}
-	return &Transaction{tx}, nil
+	return &Transaction{rawTx}, nil
 }
 
 // Transfer initiates a plain transaction to move funds to the contract, calling
 // its default method if one is available.
-func (c *BoundContract) Transfer(opts *TransactOpts) (*Transaction, error) {
-	tx, err := c.contract.Transfer(&opts.opts)
+func (c *BoundContract) Transfer(opts *TransactOpts) (tx *Transaction, _ error) {
+	rawTx, err := c.contract.Transfer(&opts.opts)
 	if err != nil {
 		return nil, err
 	}
-	return &Transaction{tx}, nil
+	return &Transaction{rawTx}, nil
 }

mobile/common.go

@@ -33,18 +33,18 @@ type Hash struct {
 }
 
 // NewHashFromBytes converts a slice of bytes to a hash value.
-func NewHashFromBytes(hash []byte) (*Hash, error) {
+func NewHashFromBytes(binary []byte) (hash *Hash, _ error) {
 	h := new(Hash)
-	if err := h.SetBytes(hash); err != nil {
+	if err := h.SetBytes(binary); err != nil {
 		return nil, err
 	}
 	return h, nil
 }
 
 // NewHashFromHex converts a hex string to a hash value.
-func NewHashFromHex(hash string) (*Hash, error) {
+func NewHashFromHex(hex string) (hash *Hash, _ error) {
 	h := new(Hash)
-	if err := h.SetHex(hash); err != nil {
+	if err := h.SetHex(hex); err != nil {
 		return nil, err
 	}
 	return h, nil
@@ -95,7 +95,7 @@ func (h *Hashes) Size() int {
 }
 
 // Get returns the hash at the given index from the slice.
-func (h *Hashes) Get(index int) (*Hash, error) {
+func (h *Hashes) Get(index int) (hash *Hash, _ error) {
 	if index < 0 || index >= len(h.hashes) {
 		return nil, errors.New("index out of bounds")
 	}
@@ -108,18 +108,18 @@ type Address struct {
 }
 
 // NewAddressFromBytes converts a slice of bytes to a hash value.
-func NewAddressFromBytes(address []byte) (*Address, error) {
+func NewAddressFromBytes(binary []byte) (address *Address, _ error) {
 	a := new(Address)
-	if err := a.SetBytes(address); err != nil {
+	if err := a.SetBytes(binary); err != nil {
 		return nil, err
 	}
 	return a, nil
 }
 
 // NewAddressFromHex converts a hex string to a address value.
-func NewAddressFromHex(address string) (*Address, error) {
+func NewAddressFromHex(hex string) (address *Address, _ error) {
 	a := new(Address)
-	if err := a.SetHex(address); err != nil {
+	if err := a.SetHex(hex); err != nil {
 		return nil, err
 	}
 	return a, nil
@@ -170,7 +170,7 @@ func (a *Addresses) Size() int {
 }
 
 // Get returns the address at the given index from the slice.
-func (a *Addresses) Get(index int) (*Address, error) {
+func (a *Addresses) Get(index int) (address *Address, _ error) {
 	if index < 0 || index >= len(a.addresses) {
 		return nil, errors.New("index out of bounds")
 	}

mobile/discover.go

@@ -53,7 +53,7 @@ type Enode struct {
 // and UDP discovery port 30301.
 //
 //    enode://<hex node id>@10.3.58.6:30303?discport=30301
-func NewEnode(rawurl string) (*Enode, error) {
+func NewEnode(rawurl string) (enode *Enode, _ error) {
 	node, err := discv5.ParseNode(rawurl)
 	if err != nil {
 		return nil, err
@@ -82,7 +82,7 @@ func (e *Enodes) Size() int {
 }
 
 // Get returns the enode at the given index from the slice.
-func (e *Enodes) Get(index int) (*Enode, error) {
+func (e *Enodes) Get(index int) (enode *Enode, _ error) {
 	if index < 0 || index >= len(e.nodes) {
 		return nil, errors.New("index out of bounds")
 	}

mobile/doc.go

@@ -51,6 +51,10 @@
 // should not be provided to limit the remote code complexity. Arrays should be
 // avoided as much as possible since they complicate bounds checking.
 //
+// If a method has multiple return values (e.g. some return + an error), those
+// are generated as output arguments in ObjC. To avoid weird generated names like
+// ret_0 for them, please always assign names to output variables if tuples.
+//
 // Note, a panic *cannot* cross over language boundaries, instead will result in
 // an undebuggable SEGFAULT in the process. For error handling only ever use error
 // returns, which may be the only or the second return.