plugeth/accounts/abi/type.go
Osoro Bironga 9a39c6bcb1
accounts/abi: improve documentation and names (#21540)
* accounts: abi/bid/backends; cleaned doc errors, camelCase refactors and anonymous variable assignments

* acounts/abi/bind: doc errors, anonymous parameter assignments

* accounts/abi: doc edits, camelCase refactors

* accounts/abi/bind: review fix

* reverted name changes

* name revert

Co-authored-by: Osoro Bironga <osoro@doctaroo.com>
2020-09-20 10:43:57 +02:00

402 lines
11 KiB
Go

// Copyright 2015 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 abi
import (
"errors"
"fmt"
"reflect"
"regexp"
"strconv"
"strings"
"github.com/ethereum/go-ethereum/common"
)
// Type enumerator
const (
IntTy byte = iota
UintTy
BoolTy
StringTy
SliceTy
ArrayTy
TupleTy
AddressTy
FixedBytesTy
BytesTy
HashTy
FixedPointTy
FunctionTy
)
// Type is the reflection of the supported argument type.
type Type struct {
Elem *Type
Size int
T byte // Our own type checking
stringKind string // holds the unparsed string for deriving signatures
// Tuple relative fields
TupleRawName string // Raw struct name defined in source code, may be empty.
TupleElems []*Type // Type information of all tuple fields
TupleRawNames []string // Raw field name of all tuple fields
TupleType reflect.Type // Underlying struct of the tuple
}
var (
// typeRegex parses the abi sub types
typeRegex = regexp.MustCompile("([a-zA-Z]+)(([0-9]+)(x([0-9]+))?)?")
)
// NewType creates a new reflection type of abi type given in t.
func NewType(t string, internalType string, components []ArgumentMarshaling) (typ Type, err error) {
// check that array brackets are equal if they exist
if strings.Count(t, "[") != strings.Count(t, "]") {
return Type{}, fmt.Errorf("invalid arg type in abi")
}
typ.stringKind = t
// if there are brackets, get ready to go into slice/array mode and
// recursively create the type
if strings.Count(t, "[") != 0 {
// Note internalType can be empty here.
subInternal := internalType
if i := strings.LastIndex(internalType, "["); i != -1 {
subInternal = subInternal[:i]
}
// recursively embed the type
i := strings.LastIndex(t, "[")
embeddedType, err := NewType(t[:i], subInternal, components)
if err != nil {
return Type{}, err
}
// grab the last cell and create a type from there
sliced := t[i:]
// grab the slice size with regexp
re := regexp.MustCompile("[0-9]+")
intz := re.FindAllString(sliced, -1)
if len(intz) == 0 {
// is a slice
typ.T = SliceTy
typ.Elem = &embeddedType
typ.stringKind = embeddedType.stringKind + sliced
} else if len(intz) == 1 {
// is an array
typ.T = ArrayTy
typ.Elem = &embeddedType
typ.Size, err = strconv.Atoi(intz[0])
if err != nil {
return Type{}, fmt.Errorf("abi: error parsing variable size: %v", err)
}
typ.stringKind = embeddedType.stringKind + sliced
} else {
return Type{}, fmt.Errorf("invalid formatting of array type")
}
return typ, err
}
// parse the type and size of the abi-type.
matches := typeRegex.FindAllStringSubmatch(t, -1)
if len(matches) == 0 {
return Type{}, fmt.Errorf("invalid type '%v'", t)
}
parsedType := matches[0]
// varSize is the size of the variable
var varSize int
if len(parsedType[3]) > 0 {
var err error
varSize, err = strconv.Atoi(parsedType[2])
if err != nil {
return Type{}, fmt.Errorf("abi: error parsing variable size: %v", err)
}
} else {
if parsedType[0] == "uint" || parsedType[0] == "int" {
// this should fail because it means that there's something wrong with
// the abi type (the compiler should always format it to the size...always)
return Type{}, fmt.Errorf("unsupported arg type: %s", t)
}
}
// varType is the parsed abi type
switch varType := parsedType[1]; varType {
case "int":
typ.Size = varSize
typ.T = IntTy
case "uint":
typ.Size = varSize
typ.T = UintTy
case "bool":
typ.T = BoolTy
case "address":
typ.Size = 20
typ.T = AddressTy
case "string":
typ.T = StringTy
case "bytes":
if varSize == 0 {
typ.T = BytesTy
} else {
typ.T = FixedBytesTy
typ.Size = varSize
}
case "tuple":
var (
fields []reflect.StructField
elems []*Type
names []string
expression string // canonical parameter expression
)
expression += "("
overloadedNames := make(map[string]string)
for idx, c := range components {
cType, err := NewType(c.Type, c.InternalType, c.Components)
if err != nil {
return Type{}, err
}
fieldName, err := overloadedArgName(c.Name, overloadedNames)
if err != nil {
return Type{}, err
}
overloadedNames[fieldName] = fieldName
fields = append(fields, reflect.StructField{
Name: fieldName, // reflect.StructOf will panic for any exported field.
Type: cType.GetType(),
Tag: reflect.StructTag("json:\"" + c.Name + "\""),
})
elems = append(elems, &cType)
names = append(names, c.Name)
expression += cType.stringKind
if idx != len(components)-1 {
expression += ","
}
}
expression += ")"
typ.TupleType = reflect.StructOf(fields)
typ.TupleElems = elems
typ.TupleRawNames = names
typ.T = TupleTy
typ.stringKind = expression
const structPrefix = "struct "
// After solidity 0.5.10, a new field of abi "internalType"
// is introduced. From that we can obtain the struct name
// user defined in the source code.
if internalType != "" && strings.HasPrefix(internalType, structPrefix) {
// Foo.Bar type definition is not allowed in golang,
// convert the format to FooBar
typ.TupleRawName = strings.Replace(internalType[len(structPrefix):], ".", "", -1)
}
case "function":
typ.T = FunctionTy
typ.Size = 24
default:
return Type{}, fmt.Errorf("unsupported arg type: %s", t)
}
return
}
// GetType returns the reflection type of the ABI type.
func (t Type) GetType() reflect.Type {
switch t.T {
case IntTy:
return reflectIntType(false, t.Size)
case UintTy:
return reflectIntType(true, t.Size)
case BoolTy:
return reflect.TypeOf(false)
case StringTy:
return reflect.TypeOf("")
case SliceTy:
return reflect.SliceOf(t.Elem.GetType())
case ArrayTy:
return reflect.ArrayOf(t.Size, t.Elem.GetType())
case TupleTy:
return t.TupleType
case AddressTy:
return reflect.TypeOf(common.Address{})
case FixedBytesTy:
return reflect.ArrayOf(t.Size, reflect.TypeOf(byte(0)))
case BytesTy:
return reflect.SliceOf(reflect.TypeOf(byte(0)))
case HashTy:
// hashtype currently not used
return reflect.ArrayOf(32, reflect.TypeOf(byte(0)))
case FixedPointTy:
// fixedpoint type currently not used
return reflect.ArrayOf(32, reflect.TypeOf(byte(0)))
case FunctionTy:
return reflect.ArrayOf(24, reflect.TypeOf(byte(0)))
default:
panic("Invalid type")
}
}
func overloadedArgName(rawName string, names map[string]string) (string, error) {
fieldName := ToCamelCase(rawName)
if fieldName == "" {
return "", errors.New("abi: purely anonymous or underscored field is not supported")
}
// Handle overloaded fieldNames
_, ok := names[fieldName]
for idx := 0; ok; idx++ {
fieldName = fmt.Sprintf("%s%d", ToCamelCase(rawName), idx)
_, ok = names[fieldName]
}
return fieldName, nil
}
// String implements Stringer.
func (t Type) String() (out string) {
return t.stringKind
}
func (t Type) pack(v reflect.Value) ([]byte, error) {
// dereference pointer first if it's a pointer
v = indirect(v)
if err := typeCheck(t, v); err != nil {
return nil, err
}
switch t.T {
case SliceTy, ArrayTy:
var ret []byte
if t.requiresLengthPrefix() {
// append length
ret = append(ret, packNum(reflect.ValueOf(v.Len()))...)
}
// calculate offset if any
offset := 0
offsetReq := isDynamicType(*t.Elem)
if offsetReq {
offset = getTypeSize(*t.Elem) * v.Len()
}
var tail []byte
for i := 0; i < v.Len(); i++ {
val, err := t.Elem.pack(v.Index(i))
if err != nil {
return nil, err
}
if !offsetReq {
ret = append(ret, val...)
continue
}
ret = append(ret, packNum(reflect.ValueOf(offset))...)
offset += len(val)
tail = append(tail, val...)
}
return append(ret, tail...), nil
case TupleTy:
// (T1,...,Tk) for k >= 0 and any types T1, …, Tk
// enc(X) = head(X(1)) ... head(X(k)) tail(X(1)) ... tail(X(k))
// where X = (X(1), ..., X(k)) and head and tail are defined for Ti being a static
// type as
// head(X(i)) = enc(X(i)) and tail(X(i)) = "" (the empty string)
// and as
// head(X(i)) = enc(len(head(X(1)) ... head(X(k)) tail(X(1)) ... tail(X(i-1))))
// tail(X(i)) = enc(X(i))
// otherwise, i.e. if Ti is a dynamic type.
fieldmap, err := mapArgNamesToStructFields(t.TupleRawNames, v)
if err != nil {
return nil, err
}
// Calculate prefix occupied size.
offset := 0
for _, elem := range t.TupleElems {
offset += getTypeSize(*elem)
}
var ret, tail []byte
for i, elem := range t.TupleElems {
field := v.FieldByName(fieldmap[t.TupleRawNames[i]])
if !field.IsValid() {
return nil, fmt.Errorf("field %s for tuple not found in the given struct", t.TupleRawNames[i])
}
val, err := elem.pack(field)
if err != nil {
return nil, err
}
if isDynamicType(*elem) {
ret = append(ret, packNum(reflect.ValueOf(offset))...)
tail = append(tail, val...)
offset += len(val)
} else {
ret = append(ret, val...)
}
}
return append(ret, tail...), nil
default:
return packElement(t, v)
}
}
// requireLengthPrefix returns whether the type requires any sort of length
// prefixing.
func (t Type) requiresLengthPrefix() bool {
return t.T == StringTy || t.T == BytesTy || t.T == SliceTy
}
// isDynamicType returns true if the type is dynamic.
// The following types are called “dynamic”:
// * bytes
// * string
// * T[] for any T
// * T[k] for any dynamic T and any k >= 0
// * (T1,...,Tk) if Ti is dynamic for some 1 <= i <= k
func isDynamicType(t Type) bool {
if t.T == TupleTy {
for _, elem := range t.TupleElems {
if isDynamicType(*elem) {
return true
}
}
return false
}
return t.T == StringTy || t.T == BytesTy || t.T == SliceTy || (t.T == ArrayTy && isDynamicType(*t.Elem))
}
// getTypeSize returns the size that this type needs to occupy.
// We distinguish static and dynamic types. Static types are encoded in-place
// and dynamic types are encoded at a separately allocated location after the
// current block.
// So for a static variable, the size returned represents the size that the
// variable actually occupies.
// For a dynamic variable, the returned size is fixed 32 bytes, which is used
// to store the location reference for actual value storage.
func getTypeSize(t Type) int {
if t.T == ArrayTy && !isDynamicType(*t.Elem) {
// Recursively calculate type size if it is a nested array
if t.Elem.T == ArrayTy || t.Elem.T == TupleTy {
return t.Size * getTypeSize(*t.Elem)
}
return t.Size * 32
} else if t.T == TupleTy && !isDynamicType(t) {
total := 0
for _, elem := range t.TupleElems {
total += getTypeSize(*elem)
}
return total
}
return 32
}