accounts/abi/bind: parse ABI once

[MariusVanDerWijden]

This moves the initialization of the parsedABI object from the Deploy()
function into a var that gets executed on startup. This means deploying
the same contract multiple times becomes faster, as the ABI doesn't have
to be parsed every time. It does increase the memory usage by requiring
everyone to hold the ABI object in memory even if the contract is not
going to be deployed.

closes #22269

example: (updated)

// ReverterMetaData contains all meta data concerning the Reverter contract.
var ReverterMetaData = &bind.MetaData{
	ABI: "[{\"constant\":false,\"inputs\":[],\"name\":\"revert\",\"outputs\":[],\"payable\":false,\"stateMutability\":\"nonpayable\",\"type\":\"function\"}]",
	Sigs: map[string]string{
		"7da3c3ab": "revert()",
	},
	Bin: "0x6080604052348015600f57600080fd5b5060ab8061001e6000396000f3fe6080604052348015600f57600080fd5b506004361060285760003560e01c80637da3c3ab14602d575b600080fd5b60336035565b005b6040805162461bcd60e51b815260206004820152601160248201527072657665727420726561736f6e2031323360781b604482015290519081900360640190fdfea265627a7a72315820e8c3f899c32798b10b8d46594292b9e3d2271f011100fb17b6d3a6469f50c8c964736f6c63430005100032",
}

// ReverterABI is the input ABI used to generate the binding from.
// Deprecated: Use ReverterMetaData.ABI instead.
var ReverterABI = ReverterMetaData.ABI

// Deprecated: Use ReverterMetaData.Sigs instead.
// ReverterFuncSigs maps the 4-byte function signature to its string representation.
var ReverterFuncSigs = ReverterMetaData.Sigs

// ReverterBin is the compiled bytecode used for deploying new contracts.
// Deprecated: Use ReverterMetaData.Bin instead.
var ReverterBin = ReverterMetaData.Bin

// DeployReverter deploys a new Ethereum contract, binding an instance of Reverter to it.
func DeployReverter(auth *bind.TransactOpts, backend bind.ContractBackend) (common.Address, *types.Transaction, *Reverter, error) {
	parsed, err := ReverterMetaData.GetAbi()
	if err != nil {
		return common.Address{}, nil, nil, err
	}
	if parsed == nil {
		return common.Address{}, nil, nil, errors.New("GetABI returned nil")
	}

	address, tx, contract, err := bind.DeployContract(auth, *parsed, common.FromHex(ReverterBin), backend)
	if err != nil {
		return common.Address{}, nil, nil, err
	}
	return address, tx, &Reverter{ReverterCaller: ReverterCaller{contract: contract}, ReverterTransactor: ReverterTransactor{contract: contract}, ReverterFilterer: ReverterFilterer{contract: contract}}, nil
}

[holiman]

What is the full example? I'm wondering about the scope, really, because parsingErr -- is that in the global scope? If so, it will conflict with other contracts.

[MariusVanDerWijden]

Oh you're right, that will clash with other definitions

[holiman]

How about something like this? That makes it still load dynamically, but does so thread-safe and does not clutter the global scope with a lot of random things. The parsedAbi definition would not be dynamically generated, but only defined once.

package foo

type parsedAbi struct {
	mu   sync.Mutex
	sigs map[string]string
	bin  []byte
	ab   *abi.ABI
}

func (p *parsedAbi) getAbi(source string) (*abi.ABI, error) {
	p.mu.Lock()
	defer p.mu.Unlock()
	if p.ab != nil {
		return p.ab
	}
	if parsed, err := abi.JSON(strings.NewReader(source)); err != nil {
		return nil, err
	} else {
		p.ab = parsed
	}
}

var reverter = &parsedAbi{
	sigs: map[string]string{"7da3c3ab": "revert()"},
	bin:  common.FromHex("0x6080604052348015600f57600080fd5b5060ab8061001e6000396000f3fe6080604052348015600f57600080fd5b506004361060285760003560e01c80637da3c3ab14602d575b600080fd5b60336035565b005b6040805162461bcd60e51b815260206004820152601160248201527072657665727420726561736f6e2031323360781b604482015290519081900360640190fdfea265627a7a72315820e8c3f899c32798b10b8d46594292b9e3d2271f011100fb17b6d3a6469f50c8c964736f6c63430005100032"),
}

// DeployReverter deploys a new Ethereum contract, binding an instance of Reverter to it.
func DeployReverter(auth *bind.TransactOpts, backend bind.ContractBackend) (common.Address, *types.Transaction, *Reverter, error) {
	rAbi, err := reverter.getAbi(ReverterABI)
	if err != nil {
		return common.Address{}, nil, nil, err
	}
	address, tx, contract, err := bind.DeployContract(auth, rAbi, rAbi.bin, backend)
	if err != nil {
		return common.Address{}, nil, nil, err
	}
	return address, tx, &Reverter{ReverterCaller: ReverterCaller{contract: contract}, ReverterTransactor: ReverterTransactor{contract: contract}, ReverterFilterer: ReverterFilterer{contract: contract}}, nil
}

[MariusVanDerWijden]

@holiman I like it, however that would break the api as ReverterBin and ReverterFuncSigs are not available anymore and anyone depending on them would need to update their code.
I do like it though, maybe with a slight modification.

package foo

type ParsedAbi struct {
	mu   sync.Mutex
	Sigs map[string]string
	Bin  []byte
	ABI string
	ab   *abi.ABI
}

func (p *ParsedAbi) getAbi() (*abi.ABI, error) {
	p.mu.Lock()
	defer p.mu.Unlock()
	if p.ab != nil {
		return p.ab
	}
	if parsed, err := abi.JSON(strings.NewReader(p.ABI)); err != nil {
		return nil, err
	} else {
		p.ab = parsed
	}
}

// ReverterMetaData contains all meta data concerning the Reverter
var ReverterMetaData = &ParsedAbi{
	Sigs: map[string]string{"7da3c3ab": "revert()"},
	ABI: "[{\"constant\":false,\"inputs\":[],\"name\":\"revert\",\"outputs\":[],\"payable\":false,\"stateMutability\":\"nonpayable\",\"type\":\"function\"}]",
	Bin:  common.FromHex("0x6080604052348015600f57600080fd5b5060ab8061001e6000396000f3fe6080604052348015600f57600080fd5b506004361060285760003560e01c80637da3c3ab14602d575b600080fd5b60336035565b005b6040805162461bcd60e51b815260206004820152601160248201527072657665727420726561736f6e2031323360781b604482015290519081900360640190fdfea265627a7a72315820e8c3f899c32798b10b8d46594292b9e3d2271f011100fb17b6d3a6469f50c8c964736f6c63430005100032"),
}

// DeployReverter deploys a new Ethereum contract, binding an instance of Reverter to it.
func DeployReverter(auth *bind.TransactOpts, backend bind.ContractBackend) (common.Address, *types.Transaction, *Reverter, error) {
	rAbi, err := ReverterMetaData.getAbi()
	if err != nil {
		return common.Address{}, nil, nil, err
	}
	address, tx, contract, err := bind.DeployContract(auth, rAbi, rAbi.Bin, backend)
	if err != nil {
		return common.Address{}, nil, nil, err
	}
	return address, tx, &Reverter{ReverterCaller: ReverterCaller{contract: contract}, ReverterTransactor: ReverterTransactor{contract: contract}, ReverterFilterer: ReverterFilterer{contract: contract}}, nil
}

[holiman]

Yeah, that looks good to me. If you don't want to break the api, maybe keep them, but remove then at some point? Something like:

// @deprecated ReverterBin is deprecated and will be removed, use ReverterMetadata.Bin  instead
var ReverterBin = ReverterMetaData.Bin

[holiman]

LGTM