accounts/abi: make a better slicing scheme

Signed-off-by: RJ Catalano <rj@monax.io>

accounts/abi/unpack.go

@@ -34,49 +34,15 @@ func toGoSlice(i int, t Argument, output []byte) (interface{}, error) {
 	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
+	// this value will become our slice or our array, depending on 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 {
+	if t.Type.T == SliceTy {
 		// 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) {
@@ -95,10 +61,13 @@ func toGoSlice(i int, t Argument, output []byte) (interface{}, error) {
 
 		// reslice to match the required size
 		slice = slice[:size*32]
-	} else if t.Type.IsArray {
+		// declare our slice
+		refSlice = reflect.MakeSlice(reflect.SliceOf(elem.Type), size, size)
+	} else if t.Type.T == ArrayTy {
 		//get the number of elements in the array
-		size = t.Type.SliceSize
+		size = t.Type.Size
-
+		// declare our slice
+		refSlice = reflect.New(reflect.ArrayOf(size, elem.Type)).Elem()
 		//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)
@@ -116,7 +85,7 @@ func toGoSlice(i int, t Argument, output []byte) (interface{}, error) {
 		// set inter to the correct type (cast)
 		switch elem.T {
 		case IntTy, UintTy:
-			inter = readInteger(t.Type.Kind, returnOutput)
+			inter = readInteger(elem.Kind, returnOutput)
 		case BoolTy:
 			inter, err = readBool(returnOutput)
 			if err != nil {
@@ -128,9 +97,14 @@ func toGoSlice(i int, t Argument, output []byte) (interface{}, error) {
 			inter = common.BytesToHash(returnOutput)
 		case FixedBytesTy:
 			inter = returnOutput
+		default:
+			return nil, fmt.Errorf("abi: unsupported slice type passed in")
 		}
+
+		//fmt.Printf("type: %T, value: %v\n", inter, inter)
+		//fmt.Printf("%v\n", elem.stringKind)
 		// append the item to our reflect slice
-		refSlice = reflect.Append(refSlice, reflect.ValueOf(inter))
+		refSlice.Index(i).Set(reflect.ValueOf(inter))
 	}
 
 	// return the interface
@@ -185,7 +159,7 @@ func readBool(word []byte) (bool, error) {
 // 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 {
+	if t.Type.T == SliceTy || t.Type.T == ArrayTy {
 		return toGoSlice(i, t, output)
 	}
 

accounts/abi/unpack_test.go

@@ -229,6 +229,187 @@ func TestSimpleMethodUnpack(t *testing.T) {
 	}
 }
 
+func TestArraysAndSlicesUnpack(t *testing.T) {
+	for i, test := range []struct {
+		def              string      // definition of the **output** ABI params
+		marshalledOutput []byte      // evm return data
+		expectedOut      interface{} // the expected output
+		outVar           interface{} // the output variable (e.g. uint32, *big.Int, etc)
+		err              string      // empty or error if expected
+	}{
+		{
+			`[ { "type": "uint8[]" } ]`,
+			common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
+			[]uint8{1, 2},
+			[]uint8{},
+			"",
+		},
+		{
+			`[ { "type": "uint8[2]" } ]`,
+			common.Hex2Bytes("00000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
+			[2]uint8{1, 2},
+			[2]uint8{},
+			"",
+		},
+		{
+			`[ { "type": "uint16[]" } ]`,
+			common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
+			[]uint16{1, 2},
+			[]uint16{},
+			"",
+		},
+		{
+			`[ { "type": "uint16[2]" } ]`,
+			common.Hex2Bytes("00000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
+			[2]uint16{1, 2},
+			[2]uint16{},
+			"",
+		},
+		{
+			`[ { "type": "uint32[]" } ]`,
+			common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
+			[]uint32{1, 2},
+			[]uint32{},
+			"",
+		},
+		{
+			`[ { "type": "uint32[2]" } ]`,
+			common.Hex2Bytes("00000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
+			[2]uint32{1, 2},
+			[2]uint32{},
+			"",
+		},
+		{
+			`[ { "type": "uint64[]" } ]`,
+			common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
+			[]uint64{1, 2},
+			[]uint64{},
+			"",
+		},
+		{
+			`[ { "type": "uint64[2]" } ]`,
+			common.Hex2Bytes("00000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
+			[2]uint64{1, 2},
+			[2]uint64{},
+			"",
+		},
+		{
+			`[ { "type": "uint256[]" } ]`,
+			common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
+			[]*big.Int{big.NewInt(1), big.NewInt(2)},
+			[]*big.Int{},
+			"",
+		},
+		{
+			`[ { "type": "uint256[3]" } ]`,
+			append(pad([]byte{1}, 32, true), append(pad([]byte{2}, 32, true), pad([]byte{3}, 32, true)...)...),
+			[3]*big.Int{big.NewInt(1), big.NewInt(2), big.NewInt(3)},
+			[3]*big.Int{},
+			"",
+		},
+		{
+			`[ { "type": "int8[]" } ]`,
+			common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
+			[]int8{1, 2},
+			[]int8{},
+			"",
+		},
+		{
+			`[ { "type": "int8[2]" } ]`,
+			common.Hex2Bytes("00000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
+			[2]int8{1, 2},
+			[2]int8{},
+			"",
+		},
+		{
+			`[ { "type": "int16[]" } ]`,
+			common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
+			[]int16{1, 2},
+			[]int16{},
+			"",
+		},
+		{
+			`[ { "type": "int16[2]" } ]`,
+			common.Hex2Bytes("00000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
+			[2]int16{1, 2},
+			[2]int16{},
+			"",
+		},
+		{
+			`[ { "type": "int32[]" } ]`,
+			common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
+			[]int32{1, 2},
+			[]int32{},
+			"",
+		},
+		{
+			`[ { "type": "int32[2]" } ]`,
+			common.Hex2Bytes("00000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
+			[2]int32{1, 2},
+			[2]int32{},
+			"",
+		},
+		{
+			`[ { "type": "int64[]" } ]`,
+			common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
+			[]int64{1, 2},
+			[]int64{},
+			"",
+		},
+		{
+			`[ { "type": "int64[2]" } ]`,
+			common.Hex2Bytes("00000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
+			[2]int64{1, 2},
+			[2]int64{},
+			"",
+		},
+		{
+			`[ { "type": "int256[]" } ]`,
+			common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
+			[]*big.Int{big.NewInt(1), big.NewInt(2)},
+			[]*big.Int{},
+			"",
+		},
+		{
+			`[ { "type": "int256[3]" } ]`,
+			common.Hex2Bytes("000000000000000000000000000000000000000000000000000000000000000100000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000003"),
+			[3]*big.Int{big.NewInt(1), big.NewInt(2), big.NewInt(3)},
+			[3]*big.Int{},
+			"",
+		},
+	} {
+
+		abiDefinition := fmt.Sprintf(`[{ "name" : "method", "outputs": %s}]`, test.def)
+		abi, err := JSON(strings.NewReader(abiDefinition))
+		if err != nil {
+			t.Errorf("%d failed. %v", i, err)
+			continue
+		}
+
+		err = abi.Unpack(&test.outVar, "method", test.marshalledOutput)
+
+		if err != nil && len(test.err) == 0 {
+			t.Errorf("%d failed. Expected no err but got: %v", i, err)
+			continue
+		}
+		if err == nil && len(test.err) != 0 {
+			t.Errorf("%d failed. Expected err: %v but got none", i, test.err)
+			continue
+		}
+		if err != nil && len(test.err) != 0 && err.Error() != test.err {
+			t.Errorf("%d failed. Expected err: '%v' got err: '%v'", i, test.err, err)
+			continue
+		}
+
+		if err == nil {
+			if !reflect.DeepEqual(test.expectedOut, test.outVar) {
+				t.Errorf("%d failed. Output error: expected %v, got %v", i, test.expectedOut, test.outVar)
+			}
+		}
+
+	}
+}
+
 func TestUnpackSetInterfaceSlice(t *testing.T) {
 	var (
 		var1 = new(uint8)