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author | RJ Catalano <catalanor0220@gmail.com> | 2017-10-17 19:07:08 +0800 |
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committer | Felix Lange <fjl@users.noreply.github.com> | 2017-10-17 19:07:08 +0800 |
commit | dec8bba9d4c5fcb3dd7e51f0f794b3e895c7f52d (patch) | |
tree | 7e4713ca276ac1a2cef7cd2dd19dcf8c6fd1f6c4 /accounts/abi/unpack.go | |
parent | e9295163aa25479e817efee4aac23eaeb7554bba (diff) | |
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accounts/abi: improve type handling, add event support (#14743)
Diffstat (limited to 'accounts/abi/unpack.go')
-rw-r--r-- | accounts/abi/unpack.go | 279 |
1 files changed, 130 insertions, 149 deletions
diff --git a/accounts/abi/unpack.go b/accounts/abi/unpack.go index fc41c88ac..ffa14ccd3 100644 --- a/accounts/abi/unpack.go +++ b/accounts/abi/unpack.go @@ -25,118 +25,16 @@ import ( "github.com/ethereum/go-ethereum/common" ) -// toGoSliceType parses the input and casts it to the proper slice defined by the ABI -// argument in T. -func toGoSlice(i int, t Argument, output []byte) (interface{}, error) { - index := i * 32 - // The slice must, at very least be large enough for the index+32 which is exactly the size required - // for the [offset in output, size of offset]. - if index+32 > len(output) { - return nil, fmt.Errorf("abi: cannot marshal in to go slice: insufficient size output %d require %d", len(output), index+32) - } - elem := t.Type.Elem - - // first we need to create a slice of the type - var refSlice reflect.Value - switch elem.T { - case IntTy, UintTy, BoolTy: - // create a new reference slice matching the element type - switch t.Type.Kind { - case reflect.Bool: - refSlice = reflect.ValueOf([]bool(nil)) - case reflect.Uint8: - refSlice = reflect.ValueOf([]uint8(nil)) - case reflect.Uint16: - refSlice = reflect.ValueOf([]uint16(nil)) - case reflect.Uint32: - refSlice = reflect.ValueOf([]uint32(nil)) - case reflect.Uint64: - refSlice = reflect.ValueOf([]uint64(nil)) - case reflect.Int8: - refSlice = reflect.ValueOf([]int8(nil)) - case reflect.Int16: - refSlice = reflect.ValueOf([]int16(nil)) - case reflect.Int32: - refSlice = reflect.ValueOf([]int32(nil)) - case reflect.Int64: - refSlice = reflect.ValueOf([]int64(nil)) - default: - refSlice = reflect.ValueOf([]*big.Int(nil)) - } - case AddressTy: // address must be of slice Address - refSlice = reflect.ValueOf([]common.Address(nil)) - case HashTy: // hash must be of slice hash - refSlice = reflect.ValueOf([]common.Hash(nil)) - case FixedBytesTy: - refSlice = reflect.ValueOf([][]byte(nil)) - default: // no other types are supported - return nil, fmt.Errorf("abi: unsupported slice type %v", elem.T) - } - - var slice []byte - var size int - var offset int - if t.Type.IsSlice { - // get the offset which determines the start of this array ... - offset = int(binary.BigEndian.Uint64(output[index+24 : index+32])) - if offset+32 > len(output) { - return nil, fmt.Errorf("abi: cannot marshal in to go slice: offset %d would go over slice boundary (len=%d)", len(output), offset+32) - } - - slice = output[offset:] - // ... starting with the size of the array in elements ... - size = int(binary.BigEndian.Uint64(slice[24:32])) - slice = slice[32:] - // ... and make sure that we've at the very least the amount of bytes - // available in the buffer. - if size*32 > len(slice) { - return nil, fmt.Errorf("abi: cannot marshal in to go slice: insufficient size output %d require %d", len(output), offset+32+size*32) - } - - // reslice to match the required size - slice = slice[:size*32] - } else if t.Type.IsArray { - //get the number of elements in the array - size = t.Type.SliceSize - - //check to make sure array size matches up - if index+32*size > len(output) { - return nil, fmt.Errorf("abi: cannot marshal in to go array: offset %d would go over slice boundary (len=%d)", len(output), index+32*size) - } - //slice is there for a fixed amount of times - slice = output[index : index+size*32] - } - - for i := 0; i < size; i++ { - var ( - inter interface{} // interface type - returnOutput = slice[i*32 : i*32+32] // the return output - err error - ) - // set inter to the correct type (cast) - switch elem.T { - case IntTy, UintTy: - inter = readInteger(t.Type.Kind, returnOutput) - case BoolTy: - inter, err = readBool(returnOutput) - if err != nil { - return nil, err - } - case AddressTy: - inter = common.BytesToAddress(returnOutput) - case HashTy: - inter = common.BytesToHash(returnOutput) - case FixedBytesTy: - inter = returnOutput - } - // append the item to our reflect slice - refSlice = reflect.Append(refSlice, reflect.ValueOf(inter)) - } - - // return the interface - return refSlice.Interface(), nil +// unpacker is a utility interface that enables us to have +// abstraction between events and methods and also to properly +// "unpack" them; e.g. events use Inputs, methods use Outputs. +type unpacker interface { + tupleUnpack(v interface{}, output []byte) error + singleUnpack(v interface{}, output []byte) error + isTupleReturn() bool } +// reads the integer based on its kind func readInteger(kind reflect.Kind, b []byte) interface{} { switch kind { case reflect.Uint8: @@ -160,13 +58,10 @@ func readInteger(kind reflect.Kind, b []byte) interface{} { } } +// reads a bool func readBool(word []byte) (bool, error) { - if len(word) != 32 { - return false, fmt.Errorf("abi: fatal error: incorrect word length") - } - - for i, b := range word { - if b != 0 && i != 31 { + for _, b := range word[:31] { + if b != 0 { return false, errBadBool } } @@ -178,58 +73,144 @@ func readBool(word []byte) (bool, error) { default: return false, errBadBool } +} +// A function type is simply the address with the function selection signature at the end. +// This enforces that standard by always presenting it as a 24-array (address + sig = 24 bytes) +func readFunctionType(t Type, word []byte) (funcTy [24]byte, err error) { + if t.T != FunctionTy { + return [24]byte{}, fmt.Errorf("abi: invalid type in call to make function type byte array.") + } + if garbage := binary.BigEndian.Uint64(word[24:32]); garbage != 0 { + err = fmt.Errorf("abi: got improperly encoded function type, got %v", word) + } else { + copy(funcTy[:], word[0:24]) + } + return } -// toGoType parses the input and casts it to the proper type defined by the ABI -// argument in T. -func toGoType(i int, t Argument, output []byte) (interface{}, error) { - // we need to treat slices differently - if (t.Type.IsSlice || t.Type.IsArray) && t.Type.T != BytesTy && t.Type.T != StringTy && t.Type.T != FixedBytesTy && t.Type.T != FunctionTy { - return toGoSlice(i, t, output) +// through reflection, creates a fixed array to be read from +func readFixedBytes(t Type, word []byte) (interface{}, error) { + if t.T != FixedBytesTy { + return nil, fmt.Errorf("abi: invalid type in call to make fixed byte array.") } + // convert + array := reflect.New(t.Type).Elem() - index := i * 32 - if index+32 > len(output) { - return nil, fmt.Errorf("abi: cannot marshal in to go type: length insufficient %d require %d", len(output), index+32) + reflect.Copy(array, reflect.ValueOf(word[0:t.Size])) + return array.Interface(), nil + +} + +// iteratively unpack elements +func forEachUnpack(t Type, output []byte, start, size int) (interface{}, error) { + if start+32*size > len(output) { + return nil, fmt.Errorf("abi: cannot marshal in to go array: offset %d would go over slice boundary (len=%d)", len(output), start+32*size) } - // Parse the given index output and check whether we need to read - // a different offset and length based on the type (i.e. string, bytes) - var returnOutput []byte - switch t.Type.T { - case StringTy, BytesTy: // variable arrays are written at the end of the return bytes - // parse offset from which we should start reading - offset := int(binary.BigEndian.Uint64(output[index+24 : index+32])) - if offset+32 > len(output) { - return nil, fmt.Errorf("abi: cannot marshal in to go type: length insufficient %d require %d", len(output), offset+32) + // this value will become our slice or our array, depending on the type + var refSlice reflect.Value + slice := output[start : start+size*32] + + if t.T == SliceTy { + // declare our slice + refSlice = reflect.MakeSlice(t.Type, size, size) + } else if t.T == ArrayTy { + // declare our array + refSlice = reflect.New(t.Type).Elem() + } else { + return nil, fmt.Errorf("abi: invalid type in array/slice unpacking stage") + } + + for i, j := start, 0; j*32 < len(slice); i, j = i+32, j+1 { + // this corrects the arrangement so that we get all the underlying array values + if t.Elem.T == ArrayTy && j != 0 { + i = start + t.Elem.Size*32*j } - // parse the size up until we should be reading - size := int(binary.BigEndian.Uint64(output[offset+24 : offset+32])) - if offset+32+size > len(output) { - return nil, fmt.Errorf("abi: cannot marshal in to go type: length insufficient %d require %d", len(output), offset+32+size) + inter, err := toGoType(i, *t.Elem, output) + if err != nil { + return nil, err } + // append the item to our reflect slice + refSlice.Index(j).Set(reflect.ValueOf(inter)) + } - // get the bytes for this return value - returnOutput = output[offset+32 : offset+32+size] - default: + // return the interface + return refSlice.Interface(), nil +} + +// toGoType parses the output bytes and recursively assigns the value of these bytes +// into a go type with accordance with the ABI spec. +func toGoType(index int, t Type, output []byte) (interface{}, error) { + if index+32 > len(output) { + return nil, fmt.Errorf("abi: cannot marshal in to go type: length insufficient %d require %d", len(output), index+32) + } + + var ( + returnOutput []byte + begin, end int + err error + ) + + // if we require a length prefix, find the beginning word and size returned. + if t.requiresLengthPrefix() { + begin, end, err = lengthPrefixPointsTo(index, output) + if err != nil { + return nil, err + } + } else { returnOutput = output[index : index+32] } - // convert the bytes to whatever is specified by the ABI. - switch t.Type.T { + switch t.T { + case SliceTy: + return forEachUnpack(t, output, begin, end) + case ArrayTy: + return forEachUnpack(t, output, index, t.Size) + case StringTy: // variable arrays are written at the end of the return bytes + return string(output[begin : begin+end]), nil case IntTy, UintTy: - return readInteger(t.Type.Kind, returnOutput), nil + return readInteger(t.Kind, returnOutput), nil case BoolTy: return readBool(returnOutput) case AddressTy: return common.BytesToAddress(returnOutput), nil case HashTy: return common.BytesToHash(returnOutput), nil - case BytesTy, FixedBytesTy, FunctionTy: - return returnOutput, nil - case StringTy: - return string(returnOutput), nil + case BytesTy: + return output[begin : begin+end], nil + case FixedBytesTy: + return readFixedBytes(t, returnOutput) + case FunctionTy: + return readFunctionType(t, returnOutput) + default: + return nil, fmt.Errorf("abi: unknown type %v", t.T) + } +} + +// interprets a 32 byte slice as an offset and then determines which indice to look to decode the type. +func lengthPrefixPointsTo(index int, output []byte) (start int, length int, err error) { + offset := int(binary.BigEndian.Uint64(output[index+24 : index+32])) + if offset+32 > len(output) { + return 0, 0, fmt.Errorf("abi: cannot marshal in to go slice: offset %d would go over slice boundary (len=%d)", len(output), offset+32) + } + length = int(binary.BigEndian.Uint64(output[offset+24 : offset+32])) + if offset+32+length > len(output) { + return 0, 0, fmt.Errorf("abi: cannot marshal in to go type: length insufficient %d require %d", len(output), offset+32+length) + } + start = offset + 32 + + //fmt.Printf("LENGTH PREFIX INFO: \nsize: %v\noffset: %v\nstart: %v\n", length, offset, start) + return +} + +// checks for proper formatting of byte output +func bytesAreProper(output []byte) error { + if len(output) == 0 { + return fmt.Errorf("abi: unmarshalling empty output") + } else if len(output)%32 != 0 { + return fmt.Errorf("abi: improperly formatted output") + } else { + return nil } - return nil, fmt.Errorf("abi: unknown type %v", t.Type.T) } |