227 lines
7.2 KiB
Go
227 lines
7.2 KiB
Go
// Copyright 2016 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package abi
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import (
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"fmt"
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"reflect"
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"strings"
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)
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// indirect recursively dereferences the value until it either gets the value
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// or finds a big.Int
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func indirect(v reflect.Value) reflect.Value {
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if v.Kind() == reflect.Ptr && v.Elem().Type() != derefbigT {
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return indirect(v.Elem())
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}
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return v
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}
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// indirectInterfaceOrPtr recursively dereferences the value until value is not interface.
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func indirectInterfaceOrPtr(v reflect.Value) reflect.Value {
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if (v.Kind() == reflect.Interface || v.Kind() == reflect.Ptr) && v.Elem().IsValid() {
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return indirect(v.Elem())
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}
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return v
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}
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// reflectIntKind returns the reflect using the given size and
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// unsignedness.
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func reflectIntKindAndType(unsigned bool, size int) (reflect.Kind, reflect.Type) {
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switch size {
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case 8:
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if unsigned {
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return reflect.Uint8, uint8T
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}
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return reflect.Int8, int8T
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case 16:
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if unsigned {
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return reflect.Uint16, uint16T
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}
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return reflect.Int16, int16T
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case 32:
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if unsigned {
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return reflect.Uint32, uint32T
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}
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return reflect.Int32, int32T
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case 64:
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if unsigned {
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return reflect.Uint64, uint64T
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}
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return reflect.Int64, int64T
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}
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return reflect.Ptr, bigT
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}
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// mustArrayToBytesSlice creates a new byte slice with the exact same size as value
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// and copies the bytes in value to the new slice.
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func mustArrayToByteSlice(value reflect.Value) reflect.Value {
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slice := reflect.MakeSlice(reflect.TypeOf([]byte{}), value.Len(), value.Len())
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reflect.Copy(slice, value)
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return slice
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}
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// set attempts to assign src to dst by either setting, copying or otherwise.
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//
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// set is a bit more lenient when it comes to assignment and doesn't force an as
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// strict ruleset as bare `reflect` does.
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func set(dst, src reflect.Value) error {
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dstType, srcType := dst.Type(), src.Type()
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switch {
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case dstType.Kind() == reflect.Interface && dst.Elem().IsValid():
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return set(dst.Elem(), src)
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case dstType.Kind() == reflect.Ptr && dstType.Elem() != derefbigT:
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return set(dst.Elem(), src)
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case srcType.AssignableTo(dstType) && dst.CanSet():
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dst.Set(src)
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case dstType.Kind() == reflect.Slice && srcType.Kind() == reflect.Slice:
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return setSlice(dst, src)
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default:
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return fmt.Errorf("abi: cannot unmarshal %v in to %v", src.Type(), dst.Type())
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}
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return nil
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}
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// setSlice attempts to assign src to dst when slices are not assignable by default
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// e.g. src: [][]byte -> dst: [][15]byte
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func setSlice(dst, src reflect.Value) error {
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slice := reflect.MakeSlice(dst.Type(), src.Len(), src.Len())
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for i := 0; i < src.Len(); i++ {
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v := src.Index(i)
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reflect.Copy(slice.Index(i), v)
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}
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dst.Set(slice)
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return nil
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}
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// requireAssignable assures that `dest` is a pointer and it's not an interface.
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func requireAssignable(dst, src reflect.Value) error {
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if dst.Kind() != reflect.Ptr && dst.Kind() != reflect.Interface {
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return fmt.Errorf("abi: cannot unmarshal %v into %v", src.Type(), dst.Type())
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}
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return nil
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}
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// requireUnpackKind verifies preconditions for unpacking `args` into `kind`
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func requireUnpackKind(v reflect.Value, t reflect.Type, k reflect.Kind,
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args Arguments) error {
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switch k {
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case reflect.Struct:
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case reflect.Slice, reflect.Array:
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if minLen := args.LengthNonIndexed(); v.Len() < minLen {
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return fmt.Errorf("abi: insufficient number of elements in the list/array for unpack, want %d, got %d",
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minLen, v.Len())
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}
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default:
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return fmt.Errorf("abi: cannot unmarshal tuple into %v", t)
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}
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return nil
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}
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// mapArgNamesToStructFields maps a slice of argument names to struct fields.
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// first round: for each Exportable field that contains a `abi:""` tag
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// and this field name exists in the given argument name list, pair them together.
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// second round: for each argument name that has not been already linked,
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// find what variable is expected to be mapped into, if it exists and has not been
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// used, pair them.
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// Note this function assumes the given value is a struct value.
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func mapArgNamesToStructFields(argNames []string, value reflect.Value) (map[string]string, error) {
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typ := value.Type()
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abi2struct := make(map[string]string)
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struct2abi := make(map[string]string)
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// first round ~~~
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for i := 0; i < typ.NumField(); i++ {
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structFieldName := typ.Field(i).Name
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// skip private struct fields.
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if structFieldName[:1] != strings.ToUpper(structFieldName[:1]) {
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continue
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}
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// skip fields that have no abi:"" tag.
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var ok bool
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var tagName string
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if tagName, ok = typ.Field(i).Tag.Lookup("abi"); !ok {
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continue
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}
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// check if tag is empty.
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if tagName == "" {
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return nil, fmt.Errorf("struct: abi tag in '%s' is empty", structFieldName)
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}
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// check which argument field matches with the abi tag.
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found := false
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for _, arg := range argNames {
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if arg == tagName {
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if abi2struct[arg] != "" {
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return nil, fmt.Errorf("struct: abi tag in '%s' already mapped", structFieldName)
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}
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// pair them
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abi2struct[arg] = structFieldName
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struct2abi[structFieldName] = arg
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found = true
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}
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}
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// check if this tag has been mapped.
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if !found {
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return nil, fmt.Errorf("struct: abi tag '%s' defined but not found in abi", tagName)
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}
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}
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// second round ~~~
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for _, argName := range argNames {
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structFieldName := ToCamelCase(argName)
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if structFieldName == "" {
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return nil, fmt.Errorf("abi: purely underscored output cannot unpack to struct")
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}
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// this abi has already been paired, skip it... unless there exists another, yet unassigned
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// struct field with the same field name. If so, raise an error:
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// abi: [ { "name": "value" } ]
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// struct { Value *big.Int , Value1 *big.Int `abi:"value"`}
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if abi2struct[argName] != "" {
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if abi2struct[argName] != structFieldName &&
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struct2abi[structFieldName] == "" &&
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value.FieldByName(structFieldName).IsValid() {
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return nil, fmt.Errorf("abi: multiple variables maps to the same abi field '%s'", argName)
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}
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continue
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}
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// return an error if this struct field has already been paired.
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if struct2abi[structFieldName] != "" {
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return nil, fmt.Errorf("abi: multiple outputs mapping to the same struct field '%s'", structFieldName)
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}
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if value.FieldByName(structFieldName).IsValid() {
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// pair them
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abi2struct[argName] = structFieldName
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struct2abi[structFieldName] = argName
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} else {
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// not paired, but annotate as used, to detect cases like
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// abi : [ { "name": "value" }, { "name": "_value" } ]
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// struct { Value *big.Int }
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struct2abi[structFieldName] = argName
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}
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}
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return abi2struct, nil
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}
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