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// 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 abi
import (
"fmt"
"reflect"
"strings"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/crypto"
)
// 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.
type Event struct {
Name string
Anonymous bool
Inputs []Argument
}
// Id returns the canonical representation of the event's signature used by the
// abi definition to identify event names and types.
func (e Event) Id() common.Hash {
types := make([]string, len(e.Inputs))
i := 0
for _, input := range e.Inputs {
types[i] = input.Type.String()
i++
}
return common.BytesToHash(crypto.Keccak256([]byte(fmt.Sprintf("%v(%v)", e.Name, strings.Join(types, ",")))))
}
// unpacks an event return tuple into a struct of corresponding go types
//
// Unpacking can be done into a struct or a slice/array.
func (e Event) tupleUnpack(v interface{}, output []byte) error {
// make sure the passed value is a pointer
valueOf := reflect.ValueOf(v)
if reflect.Ptr != valueOf.Kind() {
return fmt.Errorf("abi: Unpack(non-pointer %T)", v)
}
var (
value = valueOf.Elem()
typ = value.Type()
kind = value.Kind()
)
if err := requireUnpackKind(value, typ, kind, e.Inputs, true); err != nil {
return err
}
// `i` counts the nonindexed arguments.
// `j` counts the number of complex types.
// both `i` and `j` are used to to correctly compute `data` offset.
i, j := -1, 0
for _, input := range e.Inputs {
if input.Indexed {
// Indexed arguments are not packed into data
continue
}
i++
marshalledValue, err := toGoType((i+j)*32, input.Type, output)
if err != nil {
return err
}
if input.Type.T == ArrayTy {
// combined index ('i' + 'j') need to be adjusted only by size of array, thus
// we need to decrement 'j' because 'i' was incremented
j += input.Type.Size - 1
}
reflectValue := reflect.ValueOf(marshalledValue)
switch kind {
case reflect.Struct:
for j := 0; j < typ.NumField(); j++ {
field := typ.Field(j)
// TODO read tags: `abi:"fieldName"`
if field.Name == strings.ToUpper(input.Name[:1])+input.Name[1:] {
if err := set(value.Field(j), reflectValue, input); err != nil {
return err
}
}
}
case reflect.Slice, reflect.Array:
v := value.Index(i)
if err := requireAssignable(v, reflectValue); err != nil {
return err
}
if err := set(v.Elem(), reflectValue, input); err != nil {
return err
}
}
}
return nil
}
func (e Event) isTupleReturn() bool { return len(e.Inputs) > 1 }
func (e Event) singleUnpack(v interface{}, output []byte) error {
// make sure the passed value is a pointer
valueOf := reflect.ValueOf(v)
if reflect.Ptr != valueOf.Kind() {
return fmt.Errorf("abi: Unpack(non-pointer %T)", v)
}
if e.Inputs[0].Indexed {
return fmt.Errorf("abi: attempting to unpack indexed variable into element.")
}
value := valueOf.Elem()
marshalledValue, err := toGoType(0, e.Inputs[0].Type, output)
if err != nil {
return err
}
if err := set(value, reflect.ValueOf(marshalledValue), e.Inputs[0]); err != nil {
return err
}
return nil
}
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