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authorDeterminant <[email protected]>2020-06-28 14:47:41 -0400
committerDeterminant <[email protected]>2020-06-28 14:47:41 -0400
commitd235e2c6a5788ec4a6cff15a16f56b38a3876a0d (patch)
tree5f2727f7a50ee5840f889c82776d3a30a88dd59b /accounts/abi/reflect.go
parent13ebd8bd9468e9d769d598b0ca2afb72ba78cb97 (diff)
...
Diffstat (limited to 'accounts/abi/reflect.go')
-rw-r--r--accounts/abi/reflect.go226
1 files changed, 226 insertions, 0 deletions
diff --git a/accounts/abi/reflect.go b/accounts/abi/reflect.go
new file mode 100644
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+++ 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 <http://www.gnu.org/licenses/>.
+
+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
+}