From d235e2c6a5788ec4a6cff15a16f56b38a3876a0d Mon Sep 17 00:00:00 2001 From: Determinant Date: Sun, 28 Jun 2020 14:47:41 -0400 Subject: ... --- accounts/abi/reflect.go | 226 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 226 insertions(+) create mode 100644 accounts/abi/reflect.go (limited to 'accounts/abi/reflect.go') diff --git a/accounts/abi/reflect.go b/accounts/abi/reflect.go new file mode 100644 index 0000000..73ca8fa --- /dev/null +++ b/accounts/abi/reflect.go @@ -0,0 +1,226 @@ +// Copyright 2016 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 . + +package abi + +import ( + "fmt" + "reflect" + "strings" +) + +// indirect recursively dereferences the value until it either gets the value +// or finds a big.Int +func indirect(v reflect.Value) reflect.Value { + if v.Kind() == reflect.Ptr && v.Elem().Type() != derefbigT { + return indirect(v.Elem()) + } + return v +} + +// indirectInterfaceOrPtr recursively dereferences the value until value is not interface. +func indirectInterfaceOrPtr(v reflect.Value) reflect.Value { + if (v.Kind() == reflect.Interface || v.Kind() == reflect.Ptr) && v.Elem().IsValid() { + return indirect(v.Elem()) + } + return v +} + +// reflectIntKind returns the reflect using the given size and +// unsignedness. +func reflectIntKindAndType(unsigned bool, size int) (reflect.Kind, reflect.Type) { + switch size { + case 8: + if unsigned { + return reflect.Uint8, uint8T + } + return reflect.Int8, int8T + case 16: + if unsigned { + return reflect.Uint16, uint16T + } + return reflect.Int16, int16T + case 32: + if unsigned { + return reflect.Uint32, uint32T + } + return reflect.Int32, int32T + case 64: + if unsigned { + return reflect.Uint64, uint64T + } + return reflect.Int64, int64T + } + return reflect.Ptr, bigT +} + +// mustArrayToBytesSlice creates a new byte slice with the exact same size as value +// and copies the bytes in value to the new slice. +func mustArrayToByteSlice(value reflect.Value) reflect.Value { + slice := reflect.MakeSlice(reflect.TypeOf([]byte{}), value.Len(), value.Len()) + reflect.Copy(slice, value) + return slice +} + +// set attempts to assign src to dst by either setting, copying or otherwise. +// +// set is a bit more lenient when it comes to assignment and doesn't force an as +// strict ruleset as bare `reflect` does. +func set(dst, src reflect.Value) error { + dstType, srcType := dst.Type(), src.Type() + switch { + case dstType.Kind() == reflect.Interface && dst.Elem().IsValid(): + return set(dst.Elem(), src) + case dstType.Kind() == reflect.Ptr && dstType.Elem() != derefbigT: + return set(dst.Elem(), src) + case srcType.AssignableTo(dstType) && dst.CanSet(): + dst.Set(src) + case dstType.Kind() == reflect.Slice && srcType.Kind() == reflect.Slice: + return setSlice(dst, src) + default: + return fmt.Errorf("abi: cannot unmarshal %v in to %v", src.Type(), dst.Type()) + } + return nil +} + +// setSlice attempts to assign src to dst when slices are not assignable by default +// e.g. src: [][]byte -> dst: [][15]byte +func setSlice(dst, src reflect.Value) error { + slice := reflect.MakeSlice(dst.Type(), src.Len(), src.Len()) + for i := 0; i < src.Len(); i++ { + v := src.Index(i) + reflect.Copy(slice.Index(i), v) + } + + dst.Set(slice) + return nil +} + +// requireAssignable assures that `dest` is a pointer and it's not an interface. +func requireAssignable(dst, src reflect.Value) error { + if dst.Kind() != reflect.Ptr && dst.Kind() != reflect.Interface { + return fmt.Errorf("abi: cannot unmarshal %v into %v", src.Type(), dst.Type()) + } + return nil +} + +// requireUnpackKind verifies preconditions for unpacking `args` into `kind` +func requireUnpackKind(v reflect.Value, t reflect.Type, k reflect.Kind, + args Arguments) error { + + switch k { + case reflect.Struct: + case reflect.Slice, reflect.Array: + if minLen := args.LengthNonIndexed(); v.Len() < minLen { + return fmt.Errorf("abi: insufficient number of elements in the list/array for unpack, want %d, got %d", + minLen, v.Len()) + } + default: + return fmt.Errorf("abi: cannot unmarshal tuple into %v", t) + } + return nil +} + +// mapArgNamesToStructFields maps a slice of argument names to struct fields. +// first round: for each Exportable field that contains a `abi:""` tag +// and this field name exists in the given argument name list, pair them together. +// second round: for each argument name 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. +// Note this function assumes the given value is a struct value. +func mapArgNamesToStructFields(argNames []string, 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 _, arg := range argNames { + if arg == tagName { + if abi2struct[arg] != "" { + return nil, fmt.Errorf("struct: abi tag in '%s' already mapped", structFieldName) + } + // pair them + abi2struct[arg] = structFieldName + struct2abi[structFieldName] = arg + 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 _, argName := range argNames { + + structFieldName := ToCamelCase(argName) + + if structFieldName == "" { + return nil, fmt.Errorf("abi: purely underscored output cannot unpack to struct") + } + + // 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[argName] != "" { + if abi2struct[argName] != structFieldName && + struct2abi[structFieldName] == "" && + value.FieldByName(structFieldName).IsValid() { + return nil, fmt.Errorf("abi: multiple variables maps to the same abi field '%s'", argName) + } + continue + } + + // 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[argName] = structFieldName + struct2abi[structFieldName] = argName + } else { + // not paired, but annotate as used, to detect cases like + // abi : [ { "name": "value" }, { "name": "_value" } ] + // struct { Value *big.Int } + struct2abi[structFieldName] = argName + } + } + return abi2struct, nil +} -- cgit v1.2.3