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abi: adding the method EventByID and its test (#19359) 

This function searches for an event+parameters in the ABI and returns it if found.

Co-authored-by: Victor Tran <vu.tran54@gmail.com>
Co-authored-by: Guillaume Ballet <gballet@gmail.com>
This commit is contained in:
salanfe 2019-06-24 12:52:50 +02:00 committed by Guillaume Ballet
parent 98099d6fa7
commit e4a1488b2f
2 changed files with 81 additions and 0 deletions
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13
accounts/abi/abi.go
View File

@ -21,6 +21,8 @@ import (
"encoding/json"
"fmt"
"io"
"github.com/ethereum/go-ethereum/common"
)
// The ABI holds information about a contract's context and available
@ -165,3 +167,14 @@ func (abi *ABI) MethodById(sigdata []byte) (*Method, error) {
}
return nil, fmt.Errorf("no method with id: %#x", sigdata[:4])
}
// EventByID looks an event up by its topic hash in the
// ABI and returns nil if none found.
func (abi *ABI) EventByID(topic common.Hash) (*Event, error) {
for _, event := range abi.Events {
if bytes.Equal(event.Id().Bytes(), topic.Bytes()) {
return &event, nil
}
}
return nil, fmt.Errorf("no event with id: %#x", topic.Hex())
}

68
accounts/abi/abi_test.go
View File

@ -931,3 +931,71 @@ func TestABI_MethodById(t *testing.T) {
t.Errorf("Expected error, nil is short to decode data")
}
}
func TestABI_EventById(t *testing.T) {
tests := []struct {
name string
json string
event string
}{
{
name: "",
json: `[
{"type":"event","name":"received","anonymous":false,"inputs":[
{"indexed":false,"name":"sender","type":"address"},
{"indexed":false,"name":"amount","type":"uint256"},
{"indexed":false,"name":"memo","type":"bytes"}
]
}]`,
event: "received(address,uint256,bytes)",
}, {
name: "",
json: `[
{ "constant": true, "inputs": [], "name": "name", "outputs": [ { "name": "", "type": "string" } ], "payable": false, "stateMutability": "view", "type": "function" },
{ "constant": false, "inputs": [ { "name": "_spender", "type": "address" }, { "name": "_value", "type": "uint256" } ], "name": "approve", "outputs": [ { "name": "", "type": "bool" } ], "payable": false, "stateMutability": "nonpayable", "type": "function" },
{ "constant": true, "inputs": [], "name": "totalSupply", "outputs": [ { "name": "", "type": "uint256" } ], "payable": false, "stateMutability": "view", "type": "function" },
{ "constant": false, "inputs": [ { "name": "_from", "type": "address" }, { "name": "_to", "type": "address" }, { "name": "_value", "type": "uint256" } ], "name": "transferFrom", "outputs": [ { "name": "", "type": "bool" } ], "payable": false, "stateMutability": "nonpayable", "type": "function" },
{ "constant": true, "inputs": [], "name": "decimals", "outputs": [ { "name": "", "type": "uint8" } ], "payable": false, "stateMutability": "view", "type": "function" },
{ "constant": true, "inputs": [ { "name": "_owner", "type": "address" } ], "name": "balanceOf", "outputs": [ { "name": "balance", "type": "uint256" } ], "payable": false, "stateMutability": "view", "type": "function" },
{ "constant": true, "inputs": [], "name": "symbol", "outputs": [ { "name": "", "type": "string" } ], "payable": false, "stateMutability": "view", "type": "function" },
{ "constant": false, "inputs": [ { "name": "_to", "type": "address" }, { "name": "_value", "type": "uint256" } ], "name": "transfer", "outputs": [ { "name": "", "type": "bool" } ], "payable": false, "stateMutability": "nonpayable", "type": "function" },
{ "constant": true, "inputs": [ { "name": "_owner", "type": "address" }, { "name": "_spender", "type": "address" } ], "name": "allowance", "outputs": [ { "name": "", "type": "uint256" } ], "payable": false, "stateMutability": "view", "type": "function" },
{ "payable": true, "stateMutability": "payable", "type": "fallback" },
{ "anonymous": false, "inputs": [ { "indexed": true, "name": "owner", "type": "address" }, { "indexed": true, "name": "spender", "type": "address" }, { "indexed": false, "name": "value", "type": "uint256" } ], "name": "Approval", "type": "event" },
{ "anonymous": false, "inputs": [ { "indexed": true, "name": "from", "type": "address" }, { "indexed": true, "name": "to", "type": "address" }, { "indexed": false, "name": "value", "type": "uint256" } ], "name": "Transfer", "type": "event" }
]`,
event: "Transfer(address,address,uint256)",
},
}
for testnum, test := range tests {
abi, err := JSON(strings.NewReader(test.json))
if err != nil {
t.Error(err)
}
topic := test.event
topicID := crypto.Keccak256Hash([]byte(topic))
event, err := abi.EventByID(topicID)
if err != nil {
t.Fatalf("Failed to look up ABI method: %v, test #%d", err, testnum)
}
if event == nil {
t.Errorf("We should find a event for topic %s, test #%d", topicID.Hex(), testnum)
}
if event.Id() != topicID {
t.Errorf("Event id %s does not match topic %s, test #%d", event.Id().Hex(), topicID.Hex(), testnum)
}
unknowntopicID := crypto.Keccak256Hash([]byte("unknownEvent"))
unknownEvent, err := abi.EventByID(unknowntopicID)
if err == nil {
t.Errorf("EventByID should return an error if a topic is not found, test #%d", testnum)
}
if unknownEvent != nil {
t.Errorf("We should not find any event for topic %s, test #%d", unknowntopicID.Hex(), testnum)
}
}
}