abi

package
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 Go to latest Published: Feb 19, 2021 License: MIT, GPL-3.0 Imports: 14 Imported by: 26

Documentation

Overview

Package abi implements the Ethereum ABI (Application Binary Interface).

The Ethereum ABI is strongly typed, known at compile time and static. This ABI will handle basic type casting; unsigned to signed and visa versa. It does not handle slice casting such as unsigned slice to signed slice. Bit size type casting is also handled. ints with a bit size of 32 will be properly cast to int256, etc.

Index

Examples

Constants

View Source 
const (
	IntTy byte = iota
	UintTy
	BoolTy
	StringTy
	SliceTy
	ArrayTy
	TupleTy
	AddressTy
	FixedBytesTy
	BytesTy
	HashTy
	FixedPointTy
	FunctionTy
)

Type enumerator

Variables

View Source 
var (
	// MaxUint256 is the maximum value that can be represented by a uint256.
	MaxUint256 = new(big.Int).Sub(new(big.Int).Lsh(common.Big1, 256), common.Big1)
	// MaxInt256 is the maximum value that can be represented by a int256.
	MaxInt256 = new(big.Int).Sub(new(big.Int).Lsh(common.Big1, 255), common.Big1)
)

Functions

func MakeTopics 

func MakeTopics(query ...[]interface{}) ([][]common.Hash, error)

MakeTopics converts a filter query argument list into a filter topic set.

func ParseTopics 

func ParseTopics(out interface{}, fields Arguments, topics []common.Hash) error

ParseTopics converts the indexed topic fields into actual log field values.

func ParseTopicsIntoMap 

func ParseTopicsIntoMap(out map[string]interface{}, fields Arguments, topics []common.Hash) error

ParseTopicsIntoMap converts the indexed topic field-value pairs into map key-value pairs.

func ReadFixedBytes 

func ReadFixedBytes(t Type, word []byte) (interface{}, error)

ReadFixedBytes uses reflection to create a fixed array to be read from.

func ReadInteger 

func ReadInteger(typ Type, b []byte) interface{}

ReadInteger reads the integer based on its kind and returns the appropriate value.

func ToCamelCase 

func ToCamelCase(input string) string

ToCamelCase converts an under-score string to a camel-case string

func UnpackRevert 

func UnpackRevert(data []byte) (string, error)

UnpackRevert resolves the abi-encoded revert reason. According to the solidity spec https://solidity.readthedocs.io/en/latest/control-structures.html#revert, the provided revert reason is abi-encoded as if it were a call to a function `Error(string)`. So it's a special tool for it.

Types

type ABI 

type ABI struct {
	Constructor Method
	Methods     map[string]Method
	Events      map[string]Event

	// Additional "special" functions introduced in solidity v0.6.0.
	// It's separated from the original default fallback. Each contract
	// can only define one fallback and receive function.
	Fallback Method // Note it's also used to represent legacy fallback before v0.6.0
	Receive  Method
}

The ABI holds information about a contract's context and available invokable methods. It will allow you to type check function calls and packs data accordingly.

func JSON 

func JSON(reader io.Reader) (ABI, error)

JSON returns a parsed ABI interface and error if it failed.

Example 
const definition = `[{"constant":true,"inputs":[{"name":"","type":"address"}],"name":"isBar","outputs":[{"name":"","type":"bool"}],"type":"function"}]`

abi, err := JSON(strings.NewReader(definition))
if err != nil {
	panic(err)
}
out, err := abi.Pack("isBar", common.HexToAddress("01"))
if err != nil {
	panic(err)
}

fmt.Printf("%x\n", out)

Output:

1f2c40920000000000000000000000000000000000000000000000000000000000000001

func (*ABI) EventByID 

func (abi *ABI) EventByID(topic common.Hash) (*Event, error)

EventByID looks an event up by its topic hash in the ABI and returns nil if none found.

func (*ABI) HasFallback 

func (abi *ABI) HasFallback() bool

HasFallback returns an indicator whether a fallback function is included.

func (*ABI) HasReceive 

func (abi *ABI) HasReceive() bool

HasReceive returns an indicator whether a receive function is included.

func (*ABI) MethodById 

func (abi *ABI) MethodById(sigdata []byte) (*Method, error)

MethodById looks up a method by the 4-byte id, returns nil if none found.

func (ABI) Pack 

func (abi ABI) Pack(name string, args ...interface{}) ([]byte, error)

Pack the given method name to conform the ABI. Method call's data will consist of method_id, args0, arg1, ... argN. Method id consists of 4 bytes and arguments are all 32 bytes. Method ids are created from the first 4 bytes of the hash of the methods string signature. (signature = baz(uint32,string32))

func (*ABI) UnmarshalJSON 

func (abi *ABI) UnmarshalJSON(data []byte) error

UnmarshalJSON implements json.Unmarshaler interface.

func (ABI) Unpack 

func (abi ABI) Unpack(v interface{}, name string, data []byte) (err error)

Unpack output in v according to the abi specification.

func (ABI) UnpackIntoMap 

func (abi ABI) UnpackIntoMap(v map[string]interface{}, name string, data []byte) (err error)

UnpackIntoMap unpacks a log into the provided map[string]interface{}.

type Argument 

type Argument struct {
	Name    string
	Type    Type
	Indexed bool // indexed is only used by events
}

Argument holds the name of the argument and the corresponding type. Types are used when packing and testing arguments.

func (*Argument) UnmarshalJSON 

func (argument *Argument) UnmarshalJSON(data []byte) error

UnmarshalJSON implements json.Unmarshaler interface.

type ArgumentMarshaling 

type ArgumentMarshaling struct {
	Name         string
	Type         string
	InternalType string
	Components   []ArgumentMarshaling
	Indexed      bool
}

type Arguments 

type Arguments []Argument

func (Arguments) NonIndexed 

func (arguments Arguments) NonIndexed() Arguments

NonIndexed returns the arguments with indexed arguments filtered out.

func (Arguments) Pack 

func (arguments Arguments) Pack(args ...interface{}) ([]byte, error)

Pack performs the operation Go format -> Hexdata.

func (Arguments) PackValues 

func (arguments Arguments) PackValues(args []interface{}) ([]byte, error)

PackValues performs the operation Go format -> Hexdata. It is the semantic opposite of UnpackValues.

func (Arguments) Unpack 

func (arguments Arguments) Unpack(v interface{}, data []byte) error

Unpack performs the operation hexdata -> Go format.

func (Arguments) UnpackIntoMap 

func (arguments Arguments) UnpackIntoMap(v map[string]interface{}, data []byte) error

UnpackIntoMap performs the operation hexdata -> mapping of argument name to argument value.

func (Arguments) UnpackValues 

func (arguments Arguments) UnpackValues(data []byte) ([]interface{}, error)

UnpackValues can be used to unpack ABI-encoded hexdata according to the ABI-specification, without supplying a struct to unpack into. Instead, this method returns a list containing the values. An atomic argument will be a list with one element.

type Event 

type Event struct {
	// Name is the event name used for internal representation. It's derived from
	// the raw name and a suffix will be added in the case of a event overload.
	//
	// e.g.
	// These are two events that have the same name:
	// * foo(int,int)
	// * foo(uint,uint)
	// The event name of the first one wll be resolved as foo while the second one
	// will be resolved as foo0.
	Name string
	// RawName is the raw event name parsed from ABI.
	RawName   string
	Anonymous bool
	Inputs    Arguments

	// Sig contains the string signature according to the ABI spec.
	// e.g.	 event foo(uint32 a, int b) = "foo(uint32,int256)"
	// Please note that "int" is substitute for its canonical representation "int256"
	Sig string
	// ID returns the canonical representation of the event's signature used by the
	// abi definition to identify event names and types.
	ID common.Hash
	// contains filtered or unexported fields
}

Event is an event potentially triggered by the EVM's LOG mechanism. The Event holds type information (inputs) about the yielded output. Anonymous events don't get the signature canonical representation as the first LOG topic.

func NewEvent 

func NewEvent(name, rawName string, anonymous bool, inputs Arguments) Event

NewEvent creates a new Event. It sanitizes the input arguments to remove unnamed arguments. It also precomputes the id, signature and string representation of the event.

func (Event) String 

func (e Event) String() string

type FunctionType 

type FunctionType int

FunctionType represents different types of functions a contract might have. 

const (
	// Constructor represents the constructor of the contract.
	// The constructor function is called while deploying a contract.
	Constructor FunctionType = iota
	// Fallback represents the fallback function.
	// This function is executed if no other function matches the given function
	// signature and no receive function is specified.
	Fallback
	// Receive represents the receive function.
	// This function is executed on plain Ether transfers.
	Receive
	// Function represents a normal function.
	Function
)

type Method 

type Method struct {
	// Name is the method name used for internal representation. It's derived from
	// the raw name and a suffix will be added in the case of a function overload.
	//
	// e.g.
	// These are two functions that have the same name:
	// * foo(int,int)
	// * foo(uint,uint)
	// The method name of the first one will be resolved as foo while the second one
	// will be resolved as foo0.
	Name    string
	RawName string // RawName is the raw method name parsed from ABI

	// Type indicates whether the method is a
	// special fallback introduced in solidity v0.6.0
	Type FunctionType

	// StateMutability indicates the mutability state of method,
	// the default value is nonpayable. It can be empty if the abi
	// is generated by legacy compiler.
	StateMutability string

	// Legacy indicators generated by compiler before v0.6.0
	Constant bool
	Payable  bool

	Inputs  Arguments
	Outputs Arguments

	// Sig returns the methods string signature according to the ABI spec.
	// e.g.		function foo(uint32 a, int b) = "foo(uint32,int256)"
	// Please note that "int" is substitute for its canonical representation "int256"
	Sig string
	// ID returns the canonical representation of the method's signature used by the
	// abi definition to identify method names and types.
	ID []byte
	// contains filtered or unexported fields
}

Method represents a callable given a `Name` and whether the method is a constant. If the method is `Const` no transaction needs to be created for this particular Method call. It can easily be simulated using a local VM. For example a `Balance()` method only needs to retrieve something from the storage and therefore requires no Tx to be sent to the network. A method such as `Transact` does require a Tx and thus will be flagged `false`. Input specifies the required input parameters for this gives method.

func NewMethod 

func NewMethod(name string, rawName string, funType FunctionType, mutability string, isConst, isPayable bool, inputs Arguments, outputs Arguments) Method

NewMethod creates a new Method. A method should always be created using NewMethod. It also precomputes the sig representation and the string representation of the method.

func (Method) IsConstant 

func (method Method) IsConstant() bool

IsConstant returns the indicator whether the method is read-only.

func (Method) IsPayable 

func (method Method) IsPayable() bool

IsPayable returns the indicator whether the method can process plain ether transfers.

func (Method) String 

func (method Method) String() string

type Type 

type Type struct {
	Elem *Type
	Size int
	T    byte // Our own type checking

	// Tuple relative fields
	TupleRawName  string       // Raw struct name defined in source code, may be empty.
	TupleElems    []*Type      // Type information of all tuple fields
	TupleRawNames []string     // Raw field name of all tuple fields
	TupleType     reflect.Type // Underlying struct of the tuple
	// contains filtered or unexported fields
}

Type is the reflection of the supported argument type.

func NewType 

func NewType(t string, internalType string, components []ArgumentMarshaling) (typ Type, err error)

NewType creates a new reflection type of abi type given in t.

func (Type) GetType 

func (t Type) GetType() reflect.Type

GetType returns the reflection type of the ABI type.

func (Type) String 

func (t Type) String() (out string)

String implements Stringer.

Source Files

View all Source files

Directories

Path Synopsis
Package bind generates Ethereum contract Go bindings.
 Package bind generates Ethereum contract Go bindings.

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