path: root/core/types/receipt.go

// Copyright 2014 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 types

import (
    "encoding/json"
    "errors"
    "fmt"
    "io"
    "math/big"

    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/core/vm"
    "github.com/ethereum/go-ethereum/rlp"
)

var (
    errMissingReceiptPostState = errors.New("missing post state root in JSON receipt")
    errMissingReceiptFields    = errors.New("missing required JSON receipt fields")
)

// Receipt represents the results of a transaction.
type Receipt struct {
    // Consensus fields
    PostState         []byte
    CumulativeGasUsed *big.Int
    Bloom             Bloom
    Logs              vm.Logs

    // Implementation fields (don't reorder!)
    TxHash          common.Hash
    ContractAddress common.Address
    GasUsed         *big.Int
}

type jsonReceipt struct {
    PostState         *common.Hash    `json:"root"`
    CumulativeGasUsed *hexBig         `json:"cumulativeGasUsed"`
    Bloom             *Bloom          `json:"logsBloom"`
    Logs              *vm.Logs        `json:"logs"`
    TxHash            *common.Hash    `json:"transactionHash"`
    ContractAddress   *common.Address `json:"contractAddress"`
    GasUsed           *hexBig         `json:"gasUsed"`
}

// NewReceipt creates a barebone transaction receipt, copying the init fields.
func NewReceipt(root []byte, cumulativeGasUsed *big.Int) *Receipt {
    return &Receipt{PostState: common.CopyBytes(root), CumulativeGasUsed: new(big.Int).Set(cumulativeGasUsed)}
}

// EncodeRLP implements rlp.Encoder, and flattens the consensus fields of a receipt
// into an RLP stream.
func (r *Receipt) EncodeRLP(w io.Writer) error {
    return rlp.Encode(w, []interface{}{r.PostState, r.CumulativeGasUsed, r.Bloom, r.Logs})
}

// DecodeRLP implements rlp.Decoder, and loads the consensus fields of a receipt
// from an RLP stream.
func (r *Receipt) DecodeRLP(s *rlp.Stream) error {
    var receipt struct {
        PostState         []byte
        CumulativeGasUsed *big.Int
        Bloom             Bloom
        Logs              vm.Logs
    }
    if err := s.Decode(&receipt); err != nil {
        return err
    }
    r.PostState, r.CumulativeGasUsed, r.Bloom, r.Logs = receipt.PostState, receipt.CumulativeGasUsed, receipt.Bloom, receipt.Logs
    return nil
}

// UnmarshalJSON decodes the web3 RPC receipt format.
func (r *Receipt) UnmarshalJSON(input []byte) error {
    var dec jsonReceipt
    if err := json.Unmarshal(input, &dec); err != nil {
        return err
    }
    // Ensure that all fields are set. PostState is checked separately because it is a
    // recent addition to the RPC spec (as of August 2016) and older implementations might
    // not provide it. Note that ContractAddress is not checked because it can be null.
    if dec.PostState == nil {
        return errMissingReceiptPostState
    }
    if dec.CumulativeGasUsed == nil || dec.Bloom == nil ||
        dec.Logs == nil || dec.TxHash == nil || dec.GasUsed == nil {
        return errMissingReceiptFields
    }
    *r = Receipt{
        PostState:         (*dec.PostState)[:],
        CumulativeGasUsed: (*big.Int)(dec.CumulativeGasUsed),
        Bloom:             *dec.Bloom,
        Logs:              *dec.Logs,
        TxHash:            *dec.TxHash,
        GasUsed:           (*big.Int)(dec.GasUsed),
    }
    if dec.ContractAddress != nil {
        r.ContractAddress = *dec.ContractAddress
    }
    return nil
}

// String implements the Stringer interface.
func (r *Receipt) String() string {
    return fmt.Sprintf("receipt{med=%x cgas=%v bloom=%x logs=%v}", r.PostState, r.CumulativeGasUsed, r.Bloom, r.Logs)
}

// ReceiptForStorage is a wrapper around a Receipt that flattens and parses the
// entire content of a receipt, as opposed to only the consensus fields originally.
type ReceiptForStorage Receipt

// EncodeRLP implements rlp.Encoder, and flattens all content fields of a receipt
// into an RLP stream.
func (r *ReceiptForStorage) EncodeRLP(w io.Writer) error {
    logs := make([]*vm.LogForStorage, len(r.Logs))
    for i, log := range r.Logs {
        logs[i] = (*vm.LogForStorage)(log)
    }
    return rlp.Encode(w, []interface{}{r.PostState, r.CumulativeGasUsed, r.Bloom, r.TxHash, r.ContractAddress, logs, r.GasUsed})
}

// DecodeRLP implements rlp.Decoder, and loads both consensus and implementation
// fields of a receipt from an RLP stream.
func (r *ReceiptForStorage) DecodeRLP(s *rlp.Stream) error {
    var receipt struct {
        PostState         []byte
        CumulativeGasUsed *big.Int
        Bloom             Bloom
        TxHash            common.Hash
        ContractAddress   common.Address
        Logs              []*vm.LogForStorage
        GasUsed           *big.Int
    }
    if err := s.Decode(&receipt); err != nil {
        return err
    }
    // Assign the consensus fields
    r.PostState, r.CumulativeGasUsed, r.Bloom = receipt.PostState, receipt.CumulativeGasUsed, receipt.Bloom
    r.Logs = make(vm.Logs, len(receipt.Logs))
    for i, log := range receipt.Logs {
        r.Logs[i] = (*vm.Log)(log)
    }
    // Assign the implementation fields
    r.TxHash, r.ContractAddress, r.GasUsed = receipt.TxHash, receipt.ContractAddress, receipt.GasUsed

    return nil
}

// Receipts is a wrapper around a Receipt array to implement DerivableList.
type Receipts []*Receipt

// Len returns the number of receipts in this list.
func (r Receipts) Len() int { return len(r) }

// GetRlp returns the RLP encoding of one receipt from the list.
func (r Receipts) GetRlp(i int) []byte {
    bytes, err := rlp.EncodeToBytes(r[i])
    if err != nil {
        panic(err)
    }
    return bytes
}