140 lines
4.2 KiB
Go
140 lines
4.2 KiB
Go
// Copyright 2016 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package abi
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import (
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"fmt"
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"reflect"
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"strings"
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"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/crypto"
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)
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// Event is an event potentially triggered by the EVM's LOG mechanism. The Event
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// holds type information (inputs) about the yielded output. Anonymous events
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// don't get the signature canonical representation as the first LOG topic.
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type Event struct {
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Name string
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Anonymous bool
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Inputs []Argument
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}
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// Id returns the canonical representation of the event's signature used by the
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// abi definition to identify event names and types.
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func (e Event) Id() common.Hash {
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types := make([]string, len(e.Inputs))
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i := 0
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for _, input := range e.Inputs {
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types[i] = input.Type.String()
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i++
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}
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return common.BytesToHash(crypto.Keccak256([]byte(fmt.Sprintf("%v(%v)", e.Name, strings.Join(types, ",")))))
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}
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// unpacks an event return tuple into a struct of corresponding go types
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//
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// Unpacking can be done into a struct or a slice/array.
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func (e Event) tupleUnpack(v interface{}, output []byte) error {
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// make sure the passed value is a pointer
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valueOf := reflect.ValueOf(v)
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if reflect.Ptr != valueOf.Kind() {
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return fmt.Errorf("abi: Unpack(non-pointer %T)", v)
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}
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var (
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value = valueOf.Elem()
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typ = value.Type()
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)
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if value.Kind() != reflect.Struct {
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return fmt.Errorf("abi: cannot unmarshal tuple in to %v", typ)
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}
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j := 0
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for i := 0; i < len(e.Inputs); i++ {
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input := e.Inputs[i]
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if input.Indexed {
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// can't read, continue
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continue
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}
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marshalledValue, err := toGoType((i+j)*32, input.Type, output)
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if err != nil {
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return err
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}
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if input.Type.T == ArrayTy {
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// combined index ('i' + 'j') need to be adjusted only by size of array, thus
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// we need to decrement 'j' because 'i' was incremented
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j += input.Type.Size - 1
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}
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reflectValue := reflect.ValueOf(marshalledValue)
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switch value.Kind() {
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case reflect.Struct:
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for j := 0; j < typ.NumField(); j++ {
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field := typ.Field(j)
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// TODO read tags: `abi:"fieldName"`
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if field.Name == strings.ToUpper(e.Inputs[i].Name[:1])+e.Inputs[i].Name[1:] {
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if err := set(value.Field(j), reflectValue, e.Inputs[i]); err != nil {
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return err
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}
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}
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}
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case reflect.Slice, reflect.Array:
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if value.Len() < i {
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return fmt.Errorf("abi: insufficient number of arguments for unpack, want %d, got %d", len(e.Inputs), value.Len())
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}
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v := value.Index(i)
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if v.Kind() != reflect.Ptr && v.Kind() != reflect.Interface {
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return fmt.Errorf("abi: cannot unmarshal %v in to %v", v.Type(), reflectValue.Type())
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}
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reflectValue := reflect.ValueOf(marshalledValue)
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if err := set(v.Elem(), reflectValue, e.Inputs[i]); err != nil {
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return err
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}
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default:
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return fmt.Errorf("abi: cannot unmarshal tuple in to %v", typ)
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}
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}
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return nil
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}
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func (e Event) isTupleReturn() bool { return len(e.Inputs) > 1 }
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func (e Event) singleUnpack(v interface{}, output []byte) error {
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// make sure the passed value is a pointer
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valueOf := reflect.ValueOf(v)
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if reflect.Ptr != valueOf.Kind() {
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return fmt.Errorf("abi: Unpack(non-pointer %T)", v)
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}
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if e.Inputs[0].Indexed {
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return fmt.Errorf("abi: attempting to unpack indexed variable into element.")
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}
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value := valueOf.Elem()
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marshalledValue, err := toGoType(0, e.Inputs[0].Type, output)
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if err != nil {
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return err
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}
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if err := set(value, reflect.ValueOf(marshalledValue), e.Inputs[0]); err != nil {
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return err
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}
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return nil
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}
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