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accounts/abi: remove check for len%32==0 when unpacking events (#15670)

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This change inlines the logic of bytesAreProper at its sole
callsite, ABI.Unpack, and applies the multiple-of-32 test only in
the case of unpacking methods. Event data is not required to be a
multiple of 32 bytes long.
This commit is contained in:
Bob Glickstein 2017-12-21 01:59:14 -08:00 committed by Felix Lange
parent 9f1007e554
commit e21aa0fda3
3 changed files with 47 additions and 13 deletions
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8
accounts/abi/abi.go
View File

@ -74,13 +74,17 @@ func (abi ABI) Pack(name string, args ...interface{}) ([]byte, error) {
// Unpack output in v according to the abi specification
func (abi ABI) Unpack(v interface{}, name string, output []byte) (err error) {
if err = bytesAreProper(output); err != nil {
return err
if len(output) == 0 {
return fmt.Errorf("abi: unmarshalling empty output")
}
// since there can't be naming collisions with contracts and events,
// we need to decide whether we're calling a method or an event
var unpack unpacker
if method, ok := abi.Methods[name]; ok {
if len(output)%32 != 0 {
return fmt.Errorf("abi: improperly formatted output")
}
unpack = method
} else if event, ok := abi.Events[name]; ok {
unpack = event

41
accounts/abi/abi_test.go
View File

@ -18,6 +18,7 @@ package abi
import (
"bytes"
"encoding/hex"
"fmt"
"log"
"math/big"
@ -418,3 +419,43 @@ func TestBareEvents(t *testing.T) {
}
}
}
// TestUnpackEvent is based on this contract:
// contract T {
// event received(address sender, uint amount, bytes memo);
// function receive(bytes memo) external payable {
// received(msg.sender, msg.value, memo);
// }
// }
// When receive("X") is called with sender 0x00... and value 1, it produces this tx receipt:
// receipt{status=1 cgas=23949 bloom=00000000004000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000800000000000000000000000000000000000040200000000000000000000000000000000001000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000080000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 logs=[log: b6818c8064f645cd82d99b59a1a267d6d61117ef [75fd880d39c1daf53b6547ab6cb59451fc6452d27caa90e5b6649dd8293b9eed] 000000000000000000000000376c47978271565f56deb45495afa69e59c16ab200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000060000000000000000000000000000000000000000000000000000000000000000158 9ae378b6d4409eada347a5dc0c180f186cb62dc68fcc0f043425eb917335aa28 0 95d429d309bb9d753954195fe2d69bd140b4ae731b9b5b605c34323de162cf00 0]}
func TestUnpackEvent(t *testing.T) {
const abiJSON = `[{"constant":false,"inputs":[{"name":"memo","type":"bytes"}],"name":"receive","outputs":[],"payable":true,"stateMutability":"payable","type":"function"},{"anonymous":false,"inputs":[{"indexed":false,"name":"sender","type":"address"},{"indexed":false,"name":"amount","type":"uint256"},{"indexed":false,"name":"memo","type":"bytes"}],"name":"received","type":"event"}]`
abi, err := JSON(strings.NewReader(abiJSON))
if err != nil {
t.Fatal(err)
}
const hexdata = `000000000000000000000000376c47978271565f56deb45495afa69e59c16ab200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000060000000000000000000000000000000000000000000000000000000000000000158`
data, err := hex.DecodeString(hexdata)
if err != nil {
t.Fatal(err)
}
if len(data)%32 == 0 {
t.Errorf("len(data) is %d, want a non-multiple of 32", len(data))
}
type ReceivedEvent struct {
Address common.Address
Amount *big.Int
Memo []byte
}
var ev ReceivedEvent
err = abi.Unpack(&ev, "received", data)
if err != nil {
t.Error(err)
} else {
t.Logf("len(data): %d; received event: %+v", len(data), ev)
}
}

11
accounts/abi/unpack.go
View File

@ -203,14 +203,3 @@ func lengthPrefixPointsTo(index int, output []byte) (start int, length int, err
//fmt.Printf("LENGTH PREFIX INFO: \nsize: %v\noffset: %v\nstart: %v\n", length, offset, start)
return
}
// checks for proper formatting of byte output
func bytesAreProper(output []byte) error {
if len(output) == 0 {
return fmt.Errorf("abi: unmarshalling empty output")
} else if len(output)%32 != 0 {
return fmt.Errorf("abi: improperly formatted output")
} else {
return nil
}
}