go-ethereum/accounts/abi/abigen/template.go
jwasinger 64bd21393e
cmd/abigen, accounts/abi/bind: implement abigen version 2 (#31379)
This PR implements a new version of the abigen utility (v2) which exists
along with the pre-existing v1 version.

Abigen is a utility command provided by go-ethereum that, given a
solidity contract ABI definition, will generate Go code to transact/call
the contract methods, converting the method parameters/results and
structures defined in the contract into corresponding Go types. This is
useful for preventing the need to write custom boilerplate code for
contract interactions.

Methods in the generated bindings perform encoding between Go types and
Solidity ABI-encoded packed bytecode, as well as some action (e.g.
`eth_call` or creating and submitting a transaction). This limits the
flexibility of how the generated bindings can be used, and prevents
easily adding new functionality, as it will make the generated bindings
larger for each feature added.

Abigen v2 was conceived of by the observation that the only
functionality that generated Go bindings ought to perform is conversion
between Go types and ABI-encoded packed data. Go-ethereum already
provides various APIs which in conjunction with conversion methods
generated in v2 bindings can cover all functionality currently provided
by v1, and facilitate all other previously-desired use-cases.

## Generating Bindings

To generate contract bindings using abigen v2, invoke the `abigen`
command with the `--v2` flag. The functionality of all other flags is
preserved between the v2 and v1 versions.

## What is Generated in the Bindings

The execution of `abigen --v2` generates Go code containing methods
which convert between Go types and corresponding ABI-encoded data
expected by the contract. For each input-accepting contract method and
the constructor, a "packing" method is generated in the binding which
converts from Go types to the corresponding packed solidity expected by
the contract. If a method returns output, an "unpacking" method is
generated to convert this output from ABI-encoded data to the
corresponding Go types.

For contracts which emit events, an unpacking method is defined for each
event to unpack the corresponding raw log to the Go type that it
represents.

Likewise, where custom errors are defined by contracts, an unpack method
is generated to unpack raw error data into a Go type.

## Using the Generated Bindings

For a smooth user-experience, abigen v2 comes with a number of utility
functions to be used in conjunction with the generated bindings for
performing common contract interaction use-cases. These include:

* filtering for historical logs of a given topic
* watching the chain for emission of logs with a given topic
* contract deployment methods
* Call/Transact methods

https://geth.ethereum.org will be updated to include a new tutorial page
for abigen v2 with full code examples. The page currently exists in a
PR: https://github.com/ethereum/go-ethereum/pull/31390 .

There are also extensive examples of interactions with contract bindings
in [test
cases](cc855c7ede/accounts/abi/bind/v2/lib_test.go)
provided with this PR.

---------

Co-authored-by: Sina Mahmoodi <itz.s1na@gmail.com>
Co-authored-by: Felix Lange <fjl@twurst.com>
2025-03-17 15:56:55 +01:00

136 lines
5.7 KiB
Go

// Copyright 2016 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package abigen
import (
_ "embed"
"strings"
"unicode"
"github.com/ethereum/go-ethereum/accounts/abi"
)
// tmplData is the data structure required to fill the binding template.
type tmplData struct {
Package string // Name of the package to place the generated file in
Contracts map[string]*tmplContract // List of contracts to generate into this file
Libraries map[string]string // Map the bytecode's link pattern to the library name
Structs map[string]*tmplStruct // Contract struct type definitions
}
// tmplContract contains the data needed to generate an individual contract binding.
type tmplContract struct {
Type string // Type name of the main contract binding
InputABI string // JSON ABI used as the input to generate the binding from
InputBin string // Optional EVM bytecode used to generate deploy code from
FuncSigs map[string]string // Optional map: string signature -> 4-byte signature
Constructor abi.Method // Contract constructor for deploy parametrization
Calls map[string]*tmplMethod // Contract calls that only read state data
Transacts map[string]*tmplMethod // Contract calls that write state data
Fallback *tmplMethod // Additional special fallback function
Receive *tmplMethod // Additional special receive function
Events map[string]*tmplEvent // Contract events accessors
Libraries map[string]string // Same as tmplData, but filtered to only keep direct deps that the contract needs
Library bool // Indicator whether the contract is a library
}
type tmplContractV2 struct {
Type string // Type name of the main contract binding
InputABI string // JSON ABI used as the input to generate the binding from
InputBin string // Optional EVM bytecode used to generate deploy code from
Constructor abi.Method // Contract constructor for deploy parametrization
Calls map[string]*tmplMethod // All contract methods (excluding fallback, receive)
Events map[string]*tmplEvent // Contract events accessors
Libraries map[string]string // all direct library dependencies
Errors map[string]*tmplError // all errors defined
}
func newTmplContractV2(typ string, abiStr string, bytecode string, constructor abi.Method, cb *contractBinder) *tmplContractV2 {
// Strip any whitespace from the JSON ABI
strippedABI := strings.Map(func(r rune) rune {
if unicode.IsSpace(r) {
return -1
}
return r
}, abiStr)
return &tmplContractV2{
abi.ToCamelCase(typ),
strings.ReplaceAll(strippedABI, "\"", "\\\""),
strings.TrimPrefix(strings.TrimSpace(bytecode), "0x"),
constructor,
cb.calls,
cb.events,
make(map[string]string),
cb.errors,
}
}
type tmplDataV2 struct {
Package string // Name of the package to use for the generated bindings
Contracts map[string]*tmplContractV2 // Contracts that will be emitted in the bindings (keyed by contract name)
Libraries map[string]string // Map of the contract's name to link pattern
Structs map[string]*tmplStruct // Contract struct type definitions
}
// tmplMethod is a wrapper around an abi.Method that contains a few preprocessed
// and cached data fields.
type tmplMethod struct {
Original abi.Method // Original method as parsed by the abi package
Normalized abi.Method // Normalized version of the parsed method (capitalized names, non-anonymous args/returns)
Structured bool // Whether the returns should be accumulated into a struct
}
// tmplEvent is a wrapper around an abi.Event that contains a few preprocessed
// and cached data fields.
type tmplEvent struct {
Original abi.Event // Original event as parsed by the abi package
Normalized abi.Event // Normalized version of the parsed fields
}
// tmplError is a wrapper around an abi.Error that contains a few preprocessed
// and cached data fields.
type tmplError struct {
Original abi.Error
Normalized abi.Error
}
// tmplField is a wrapper around a struct field with binding language
// struct type definition and relative filed name.
type tmplField struct {
Type string // Field type representation depends on target binding language
Name string // Field name converted from the raw user-defined field name
SolKind abi.Type // Raw abi type information
}
// tmplStruct is a wrapper around an abi.tuple and contains an auto-generated
// struct name.
type tmplStruct struct {
Name string // Auto-generated struct name(before solidity v0.5.11) or raw name.
Fields []*tmplField // Struct fields definition depends on the binding language.
}
// tmplSource is the Go source template that the generated Go contract binding
// is based on.
//
//go:embed source.go.tpl
var tmplSource string
// tmplSourceV2 is the Go source template that the generated Go contract binding
// for abigen v2 is based on.
//
//go:embed source2.go.tpl
var tmplSourceV2 string