github.com/mrwater98/go-ethereum@v1.9.7/accounts/abi/event.go (about)

     1  // Copyright 2016 The go-ethereum Authors
     2  // This file is part of the go-ethereum library.
     3  //
     4  // The go-ethereum library is free software: you can redistribute it and/or modify
     5  // it under the terms of the GNU Lesser General Public License as published by
     6  // the Free Software Foundation, either version 3 of the License, or
     7  // (at your option) any later version.
     8  //
     9  // The go-ethereum library is distributed in the hope that it will be useful,
    10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    12  // GNU Lesser General Public License for more details.
    13  //
    14  // You should have received a copy of the GNU Lesser General Public License
    15  // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  package abi
    18  
    19  import (
    20  	"fmt"
    21  	"strings"
    22  
    23  	"github.com/ethereum/go-ethereum/common"
    24  	"github.com/ethereum/go-ethereum/crypto"
    25  )
    26  
    27  // Event is an event potentially triggered by the EVM's LOG mechanism. The Event
    28  // holds type information (inputs) about the yielded output. Anonymous events
    29  // don't get the signature canonical representation as the first LOG topic.
    30  type Event struct {
    31  	// Name is the event name used for internal representation. It's derived from
    32  	// the raw name and a suffix will be added in the case of a event overload.
    33  	//
    34  	// e.g.
    35  	// There are two events have same name:
    36  	// * foo(int,int)
    37  	// * foo(uint,uint)
    38  	// The event name of the first one wll be resolved as foo while the second one
    39  	// will be resolved as foo0.
    40  	Name string
    41  	// RawName is the raw event name parsed from ABI.
    42  	RawName   string
    43  	Anonymous bool
    44  	Inputs    Arguments
    45  }
    46  
    47  func (e Event) String() string {
    48  	inputs := make([]string, len(e.Inputs))
    49  	for i, input := range e.Inputs {
    50  		inputs[i] = fmt.Sprintf("%v %v", input.Type, input.Name)
    51  		if input.Indexed {
    52  			inputs[i] = fmt.Sprintf("%v indexed %v", input.Type, input.Name)
    53  		}
    54  	}
    55  	return fmt.Sprintf("event %v(%v)", e.RawName, strings.Join(inputs, ", "))
    56  }
    57  
    58  // Sig returns the event string signature according to the ABI spec.
    59  //
    60  // Example
    61  //
    62  //     event foo(uint32 a, int b) = "foo(uint32,int256)"
    63  //
    64  // Please note that "int" is substitute for its canonical representation "int256"
    65  func (e Event) Sig() string {
    66  	types := make([]string, len(e.Inputs))
    67  	for i, input := range e.Inputs {
    68  		types[i] = input.Type.String()
    69  	}
    70  	return fmt.Sprintf("%v(%v)", e.RawName, strings.Join(types, ","))
    71  }
    72  
    73  // ID returns the canonical representation of the event's signature used by the
    74  // abi definition to identify event names and types.
    75  func (e Event) ID() common.Hash {
    76  	return common.BytesToHash(crypto.Keccak256([]byte(e.Sig())))
    77  }