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accounts/abi: allow abi: tags when unpacking structs

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Go code users can now tag event struct members with `abi:` to specify in what fields the event will be de-serialized.

See PR #16648 for details.
This commit is contained in:
Guillaume Ballet 2018-05-14 14:47:31 +02:00 committed by GitHub
parent 49ec4f0cd1
commit 247b5f0369
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 195 additions and 36 deletions
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42
accounts/abi/argument.go
View File

@ -111,9 +111,14 @@ func (arguments Arguments) unpackTuple(v interface{}, marshalledValues []interfa
if err := requireUnpackKind(value, typ, kind, arguments); err != nil {
return err
}
// If the output interface is a struct, make sure names don't collide
// If the interface is a struct, get of abi->struct_field mapping
var abi2struct map[string]string
if kind == reflect.Struct {
if err := requireUniqueStructFieldNames(arguments); err != nil {
var err error
abi2struct, err = mapAbiToStructFields(arguments, value)
if err != nil {
return err
}
}
@ -123,10 +128,11 @@ func (arguments Arguments) unpackTuple(v interface{}, marshalledValues []interfa
switch kind {
case reflect.Struct:
err := unpackStruct(value, reflectValue, arg)
if err != nil {
if structField, ok := abi2struct[arg.Name]; ok {
if err := set(value.FieldByName(structField), reflectValue, arg); err != nil {
return err
}
}
case reflect.Slice, reflect.Array:
if value.Len() < i {
return fmt.Errorf("abi: insufficient number of arguments for unpack, want %d, got %d", len(arguments), value.Len())
@ -151,17 +157,22 @@ func (arguments Arguments) unpackAtomic(v interface{}, marshalledValues []interf
if len(marshalledValues) != 1 {
return fmt.Errorf("abi: wrong length, expected single value, got %d", len(marshalledValues))
}
elem := reflect.ValueOf(v).Elem()
kind := elem.Kind()
reflectValue := reflect.ValueOf(marshalledValues[0])
var abi2struct map[string]string
if kind == reflect.Struct {
//make sure names don't collide
if err := requireUniqueStructFieldNames(arguments); err != nil {
var err error
if abi2struct, err = mapAbiToStructFields(arguments, elem); err != nil {
return err
}
return unpackStruct(elem, reflectValue, arguments[0])
arg := arguments.NonIndexed()[0]
if structField, ok := abi2struct[arg.Name]; ok {
return set(elem.FieldByName(structField), reflectValue, arg)
}
return nil
}
return set(elem, reflectValue, arguments.NonIndexed()[0])
@ -277,18 +288,3 @@ func capitalise(input string) string {
}
return strings.ToUpper(input[:1]) + input[1:]
}
//unpackStruct extracts each argument into its corresponding struct field
func unpackStruct(value, reflectValue reflect.Value, arg Argument) error {
name := capitalise(arg.Name)
typ := value.Type()
for j := 0; j < typ.NumField(); j++ {
// TODO read tags: `abi:"fieldName"`
if typ.Field(j).Name == name {
if err := set(value.Field(j), reflectValue, arg); err != nil {
return err
}
}
}
return nil
}

81
accounts/abi/event_test.go
View File

@ -58,12 +58,28 @@ var jsonEventPledge = []byte(`{
"type": "event"
}`)
var jsonEventMixedCase = []byte(`{
"anonymous": false,
"inputs": [{
"indexed": false, "name": "value", "type": "uint256"
}, {
"indexed": false, "name": "_value", "type": "uint256"
}, {
"indexed": false, "name": "Value", "type": "uint256"
}],
"name": "MixedCase",
"type": "event"
}`)
// 1000000
var transferData1 = "00000000000000000000000000000000000000000000000000000000000f4240"
// "0x00Ce0d46d924CC8437c806721496599FC3FFA268", 2218516807680, "usd"
var pledgeData1 = "00000000000000000000000000ce0d46d924cc8437c806721496599fc3ffa2680000000000000000000000000000000000000000000000000000020489e800007573640000000000000000000000000000000000000000000000000000000000"
// 1000000,2218516807680,1000001
var mixedCaseData1 = "00000000000000000000000000000000000000000000000000000000000f42400000000000000000000000000000000000000000000000000000020489e8000000000000000000000000000000000000000000000000000000000000000f4241"
func TestEventId(t *testing.T) {
var table = []struct {
definition string
@ -121,6 +137,27 @@ func TestEventTupleUnpack(t *testing.T) {
Value *big.Int
}
type EventTransferWithTag struct {
// this is valid because `value` is not exportable,
// so value is only unmarshalled into `Value1`.
value *big.Int
Value1 *big.Int `abi:"value"`
}
type BadEventTransferWithSameFieldAndTag struct {
Value *big.Int
Value1 *big.Int `abi:"value"`
}
type BadEventTransferWithDuplicatedTag struct {
Value1 *big.Int `abi:"value"`
Value2 *big.Int `abi:"value"`
}
type BadEventTransferWithEmptyTag struct {
Value *big.Int `abi:""`
}
type EventPledge struct {
Who common.Address
Wad *big.Int
@ -133,9 +170,16 @@ func TestEventTupleUnpack(t *testing.T) {
Currency [3]byte
}
type EventMixedCase struct {
Value1 *big.Int `abi:"value"`
Value2 *big.Int `abi:"_value"`
Value3 *big.Int `abi:"Value"`
}
bigint := new(big.Int)
bigintExpected := big.NewInt(1000000)
bigintExpected2 := big.NewInt(2218516807680)
bigintExpected3 := big.NewInt(1000001)
addr := common.HexToAddress("0x00Ce0d46d924CC8437c806721496599FC3FFA268")
var testCases = []struct {
data string
@ -158,6 +202,34 @@ func TestEventTupleUnpack(t *testing.T) {
jsonEventTransfer,
"",
"Can unpack ERC20 Transfer event into slice",
}, {
transferData1,
&EventTransferWithTag{},
&EventTransferWithTag{Value1: bigintExpected},
jsonEventTransfer,
"",
"Can unpack ERC20 Transfer event into structure with abi: tag",
}, {
transferData1,
&BadEventTransferWithDuplicatedTag{},
&BadEventTransferWithDuplicatedTag{},
jsonEventTransfer,
"struct: abi tag in 'Value2' already mapped",
"Can not unpack ERC20 Transfer event with duplicated abi tag",
}, {
transferData1,
&BadEventTransferWithSameFieldAndTag{},
&BadEventTransferWithSameFieldAndTag{},
jsonEventTransfer,
"abi: multiple variables maps to the same abi field 'value'",
"Can not unpack ERC20 Transfer event with a field and a tag mapping to the same abi variable",
}, {
transferData1,
&BadEventTransferWithEmptyTag{},
&BadEventTransferWithEmptyTag{},
jsonEventTransfer,
"struct: abi tag in 'Value' is empty",
"Can not unpack ERC20 Transfer event with an empty tag",
}, {
pledgeData1,
&EventPledge{},
@ -216,6 +288,13 @@ func TestEventTupleUnpack(t *testing.T) {
jsonEventPledge,
"abi: cannot unmarshal tuple into map[string]interface {}",
"Can not unpack Pledge event into map",
}, {
mixedCaseData1,
&EventMixedCase{},
&EventMixedCase{Value1: bigintExpected, Value2: bigintExpected2, Value3: bigintExpected3},
jsonEventMixedCase,
"",
"Can unpack abi variables with mixed case",
}}
for _, tc := range testCases {
@ -227,7 +306,7 @@ func TestEventTupleUnpack(t *testing.T) {
assert.Nil(err, "Should be able to unpack event data.")
assert.Equal(tc.expected, tc.dest, tc.name)
} else {
assert.EqualError(err, tc.error)
assert.EqualError(err, tc.error, tc.name)
}
})
}

104
accounts/abi/reflect.go
View File

@ -19,6 +19,7 @@ package abi
import (
"fmt"
"reflect"
"strings"
)
// indirect recursively dereferences the value until it either gets the value
@ -111,18 +112,101 @@ func requireUnpackKind(v reflect.Value, t reflect.Type, k reflect.Kind,
return nil
}
// requireUniqueStructFieldNames makes sure field names don't collide
func requireUniqueStructFieldNames(args Arguments) error {
exists := make(map[string]bool)
// mapAbiToStringField maps abi to struct fields.
// first round: for each Exportable field that contains a `abi:""` tag
// and this field name exists in the arguments, pair them together.
// second round: for each argument field that has not been already linked,
// find what variable is expected to be mapped into, if it exists and has not been
// used, pair them.
func mapAbiToStructFields(args Arguments, value reflect.Value) (map[string]string, error) {
typ := value.Type()
abi2struct := make(map[string]string)
struct2abi := make(map[string]string)
// first round ~~~
for i := 0; i < typ.NumField(); i++ {
structFieldName := typ.Field(i).Name
// skip private struct fields.
if structFieldName[:1] != strings.ToUpper(structFieldName[:1]) {
continue
}
// skip fields that have no abi:"" tag.
var ok bool
var tagName string
if tagName, ok = typ.Field(i).Tag.Lookup("abi"); !ok {
continue
}
// check if tag is empty.
if tagName == "" {
return nil, fmt.Errorf("struct: abi tag in '%s' is empty", structFieldName)
}
// check which argument field matches with the abi tag.
found := false
for _, abiField := range args.NonIndexed() {
if abiField.Name == tagName {
if abi2struct[abiField.Name] != "" {
return nil, fmt.Errorf("struct: abi tag in '%s' already mapped", structFieldName)
}
// pair them
abi2struct[abiField.Name] = structFieldName
struct2abi[structFieldName] = abiField.Name
found = true
}
}
// check if this tag has been mapped.
if !found {
return nil, fmt.Errorf("struct: abi tag '%s' defined but not found in abi", tagName)
}
}
// second round ~~~
for _, arg := range args {
field := capitalise(arg.Name)
if field == "" {
return fmt.Errorf("abi: purely underscored output cannot unpack to struct")
abiFieldName := arg.Name
structFieldName := capitalise(abiFieldName)
if structFieldName == "" {
return nil, fmt.Errorf("abi: purely underscored output cannot unpack to struct")
}
if exists[field] {
return fmt.Errorf("abi: multiple outputs mapping to the same struct field '%s'", field)
// this abi has already been paired, skip it... unless there exists another, yet unassigned
// struct field with the same field name. If so, raise an error:
// abi: [ { "name": "value" } ]
// struct { Value *big.Int , Value1 *big.Int `abi:"value"`}
if abi2struct[abiFieldName] != "" {
if abi2struct[abiFieldName] != structFieldName &&
struct2abi[structFieldName] == "" &&
value.FieldByName(structFieldName).IsValid() {
return nil, fmt.Errorf("abi: multiple variables maps to the same abi field '%s'", abiFieldName)
}
exists[field] = true
continue
}
return nil
// return an error if this struct field has already been paired.
if struct2abi[structFieldName] != "" {
return nil, fmt.Errorf("abi: multiple outputs mapping to the same struct field '%s'", structFieldName)
}
if value.FieldByName(structFieldName).IsValid() {
// pair them
abi2struct[abiFieldName] = structFieldName
struct2abi[structFieldName] = abiFieldName
} else {
// not paired, but annotate as used, to detect cases like
// abi : [ { "name": "value" }, { "name": "_value" } ]
// struct { Value *big.Int }
struct2abi[structFieldName] = abiFieldName
}
}
return abi2struct, nil
}