core: vm: sqlvm: ast: return error messages from GetType

To allow callers to provide precise error messages, return an error
message in addition to an error code from GetType of TypeNode.

Drop DataTypeEncode because it is never used by any code and it has
become a simple wrapper of GetType.

4 files changed, 85 insertions, 45 deletions

diff --git a/core/vm/sqlvm/ast/ast.go b/core/vm/sqlvm/ast/ast.go
index e5de75d45..672770b84 100644
--- a/core/vm/sqlvm/ast/ast.go
+++ b/core/vm/sqlvm/ast/ast.go
@@ -1,6 +1,8 @@
 package ast
 
 import (
+	"fmt"
+
 	"github.com/dexon-foundation/dexon/core/vm/sqlvm/errors"
 	"github.com/shopspring/decimal"
 )
@@ -309,7 +311,7 @@ func (n *NullValueNode) Value() interface{} { return n }
 // TypeNode is an interface which should be satisfied nodes representing types.
 type TypeNode interface {
 	Node
-	GetType() (DataType, errors.ErrorCode)
+	GetType() (DataType, errors.ErrorCode, string)
 }
 
 // IntTypeNode represents solidity int{X} and uint{X} types.
@@ -327,12 +329,30 @@ func (n *IntTypeNode) GetChildren() []Node {
 }
 
 // GetType returns the type represented by the node.
-func (n *IntTypeNode) GetType() (DataType, errors.ErrorCode) {
-	if n.Size%8 != 0 || n.Size == 0 || n.Size > 256 {
+func (n *IntTypeNode) GetType() (DataType, errors.ErrorCode, string) {
+	isMultiple := n.Size%8 == 0
+	isNotZero := n.Size != 0
+	isInRange := n.Size <= 256
+	if !isMultiple || !isNotZero || !isInRange {
+		name := "int"
+		code := errors.ErrorCodeInvalidIntSize
 		if n.Unsigned {
-			return DataTypeUnknown, errors.ErrorCodeInvalidUintSize
+			name = "uint"
+			code = errors.ErrorCodeInvalidUintSize
+		}
+		if !isMultiple {
+			return DataTypeUnknown, code, fmt.Sprintf(
+				"%s size %d is not a multiple of 8", name, n.Size)
+		}
+		if !isNotZero {
+			return DataTypeUnknown, code, fmt.Sprintf(
+				"%s size cannot be zero", name)
 		}
-		return DataTypeUnknown, errors.ErrorCodeInvalidIntSize
+		if !isInRange {
+			return DataTypeUnknown, code, fmt.Sprintf(
+				"%s size %d cannot be larger than 256", name, n.Size)
+		}
+		panic("unreachable")
 	}
 	var major DataTypeMajor
 	var minor DataTypeMinor
@@ -342,7 +362,7 @@ func (n *IntTypeNode) GetType() (DataType, errors.ErrorCode) {
 		major = DataTypeMajorInt
 	}
 	minor = DataTypeMinor(n.Size/8 - 1)
-	return ComposeDataType(major, minor), errors.ErrorCodeNil
+	return ComposeDataType(major, minor), errors.ErrorCodeNil, ""
 }
 
 // FixedTypeNode represents solidity fixed{M}x{N} and ufixed{M}x{N} types.
@@ -361,18 +381,41 @@ func (n *FixedTypeNode) GetChildren() []Node {
 }
 
 // GetType returns the type represented by the node.
-func (n *FixedTypeNode) GetType() (DataType, errors.ErrorCode) {
-	if n.Size%8 != 0 || n.Size == 0 || n.Size > 256 {
+func (n *FixedTypeNode) GetType() (DataType, errors.ErrorCode, string) {
+	sizeIsMultiple := n.Size%8 == 0
+	sizeIsNotZero := n.Size != 0
+	sizeIsInRange := n.Size <= 256
+	fractionalDigitsInRange := n.FractionalDigits <= 80
+	if !sizeIsMultiple || !sizeIsNotZero || !sizeIsInRange ||
+		!fractionalDigitsInRange {
+		name := "fixed"
+		code := errors.ErrorCodeInvalidFixedSize
 		if n.Unsigned {
-			return DataTypeUnknown, errors.ErrorCodeInvalidUfixedSize
+			name = "ufixed"
+			code = errors.ErrorCodeInvalidFixedSize
 		}
-		return DataTypeUnknown, errors.ErrorCodeInvalidFixedSize
-	}
-	if n.FractionalDigits > 80 {
+		if !sizeIsMultiple {
+			return DataTypeUnknown, code, fmt.Sprintf(
+				"%s size %d is not a multiple of 8", name, n.Size)
+		}
+		if !sizeIsNotZero {
+			return DataTypeUnknown, code, fmt.Sprintf(
+				"%s size cannot be zero", name)
+		}
+		if !sizeIsInRange {
+			return DataTypeUnknown, code, fmt.Sprintf(
+				"%s size %d cannot be larger than 256", name, n.Size)
+		}
+		code = errors.ErrorCodeInvalidFixedFractionalDigits
 		if n.Unsigned {
-			return DataTypeUnknown, errors.ErrorCodeInvalidUfixedFractionalDigits
+			code = errors.ErrorCodeInvalidUfixedFractionalDigits
+		}
+		if !fractionalDigitsInRange {
+			return DataTypeUnknown, code, fmt.Sprintf(
+				"%s fractional digits %d cannot be larger than 80",
+				name, n.FractionalDigits)
 		}
-		return DataTypeUnknown, errors.ErrorCodeInvalidFixedFractionalDigits
+		panic("unreachable")
 	}
 	var major DataTypeMajor
 	var minor DataTypeMinor
@@ -383,7 +426,7 @@ func (n *FixedTypeNode) GetType() (DataType, errors.ErrorCode) {
 	}
 	major += DataTypeMajor(n.Size/8 - 1)
 	minor = DataTypeMinor(n.FractionalDigits)
-	return ComposeDataType(major, minor), errors.ErrorCodeNil
+	return ComposeDataType(major, minor), errors.ErrorCodeNil, ""
 }
 
 // DynamicBytesTypeNode represents solidity bytes type.
@@ -399,9 +442,9 @@ func (n *DynamicBytesTypeNode) GetChildren() []Node {
 }
 
 // GetType returns the type represented by the node.
-func (n *DynamicBytesTypeNode) GetType() (DataType, errors.ErrorCode) {
+func (n *DynamicBytesTypeNode) GetType() (DataType, errors.ErrorCode, string) {
 	return ComposeDataType(DataTypeMajorDynamicBytes, DataTypeMinorDontCare),
-		errors.ErrorCodeNil
+		errors.ErrorCodeNil, ""
 }
 
 // FixedBytesTypeNode represents solidity bytes{X} type.
@@ -418,13 +461,23 @@ func (n *FixedBytesTypeNode) GetChildren() []Node {
 }
 
 // GetType returns the type represented by the node.
-func (n *FixedBytesTypeNode) GetType() (DataType, errors.ErrorCode) {
-	if n.Size == 0 || n.Size > 32 {
-		return DataTypeUnknown, errors.ErrorCodeInvalidBytesSize
+func (n *FixedBytesTypeNode) GetType() (DataType, errors.ErrorCode, string) {
+	isNotZero := n.Size != 0
+	isInRange := n.Size <= 32
+	if !isNotZero || !isInRange {
+		code := errors.ErrorCodeInvalidBytesSize
+		if !isNotZero {
+			return DataTypeUnknown, code, "bytes size cannot be zero"
+		}
+		if !isInRange {
+			return DataTypeUnknown, code, fmt.Sprintf(
+				"bytes size %d cannot be larger than 32", n.Size)
+		}
+		panic("unreachable")
 	}
 	major := DataTypeMajorFixedBytes
 	minor := DataTypeMinor(n.Size - 1)
-	return ComposeDataType(major, minor), errors.ErrorCodeNil
+	return ComposeDataType(major, minor), errors.ErrorCodeNil, ""
 }
 
 // AddressTypeNode represents solidity address type.
@@ -440,9 +493,9 @@ func (n *AddressTypeNode) GetChildren() []Node {
 }
 
 // GetType returns the type represented by the node.
-func (n *AddressTypeNode) GetType() (DataType, errors.ErrorCode) {
+func (n *AddressTypeNode) GetType() (DataType, errors.ErrorCode, string) {
 	return ComposeDataType(DataTypeMajorAddress, DataTypeMinorDontCare),
-		errors.ErrorCodeNil
+		errors.ErrorCodeNil, ""
 }
 
 // BoolTypeNode represents solidity bool type.
@@ -458,9 +511,9 @@ func (n *BoolTypeNode) GetChildren() []Node {
 }
 
 // GetType returns the type represented by the node.
-func (n *BoolTypeNode) GetType() (DataType, errors.ErrorCode) {
+func (n *BoolTypeNode) GetType() (DataType, errors.ErrorCode, string) {
 	return ComposeDataType(DataTypeMajorBool, DataTypeMinorDontCare),
-		errors.ErrorCodeNil
+		errors.ErrorCodeNil, ""
 }
 
 // ---------------------------------------------------------------------------
@@ -825,7 +878,7 @@ func (n *CastOperatorNode) IsConstant() bool {
 
 // GetType returns the type of CAST expression, which is always the target type.
 func (n *CastOperatorNode) GetType() DataType {
-	if dt, code := n.TargetType.GetType(); code == errors.ErrorCodeNil {
+	if dt, code, _ := n.TargetType.GetType(); code == errors.ErrorCodeNil {
 		return dt
 	}
 	return DataTypeUnknown
diff --git a/core/vm/sqlvm/ast/types.go b/core/vm/sqlvm/ast/types.go
index c37e6c012..5151334a9 100644
--- a/core/vm/sqlvm/ast/types.go
+++ b/core/vm/sqlvm/ast/types.go
@@ -101,18 +101,6 @@ func (dt DataType) Size() uint8 {
 	}
 }
 
-// DataTypeEncode encodes data type node into DataType.
-func DataTypeEncode(n TypeNode) (DataType, error) {
-	if n == nil {
-		return DataTypeUnknown, se.ErrorCodeDataTypeEncode
-	}
-	t, code := n.GetType()
-	if code == se.ErrorCodeNil {
-		return t, nil
-	}
-	return t, code
-}
-
 // DataTypeDecode decodes DataType into data type node.
 func DataTypeDecode(t DataType) (TypeNode, error) {
 	major, minor := DecomposeDataType(t)
diff --git a/core/vm/sqlvm/ast/types_test.go b/core/vm/sqlvm/ast/types_test.go
index 8373aa344..15e9cdec0 100644
--- a/core/vm/sqlvm/ast/types_test.go
+++ b/core/vm/sqlvm/ast/types_test.go
@@ -25,8 +25,9 @@ func (s *TypesTestSuite) requireEncodeAndDecodeDecimalNoError(
 
 func (s *TypesTestSuite) requireEncodeAndDecodeNoError(
 	d DataType, t TypeNode) {
-	encode, err := DataTypeEncode(t)
-	s.Require().NoError(err)
+	encode, code, message := t.GetType()
+	s.Require().Zero(code)
+	s.Require().Empty(message)
 	s.Require().Equal(d, encode)
 	decode, err := DataTypeDecode(d)
 	s.Require().NoError(err)
@@ -34,8 +35,9 @@ func (s *TypesTestSuite) requireEncodeAndDecodeNoError(
 }
 
 func (s *TypesTestSuite) requireEncodeError(input TypeNode) {
-	_, err := DataTypeEncode(input)
-	s.Require().Error(err)
+	_, code, message := input.GetType()
+	s.Require().NotZero(code)
+	s.Require().NotEmpty(message)
 }
 
 func (s *TypesTestSuite) requireDecodeError(input DataType) {
@@ -71,7 +73,6 @@ func (s *TypesTestSuite) TestEncodeAndDecode() {
 }
 
 func (s *TypesTestSuite) TestEncodeError() {
-	s.requireEncodeError(nil)
 	s.requireEncodeError(&IntTypeNode{Size: 1})
 	s.requireEncodeError(&IntTypeNode{Size: 257})
 	s.requireEncodeError(&FixedBytesTypeNode{Size: 0})
diff --git a/core/vm/sqlvm/errors/errors.go b/core/vm/sqlvm/errors/errors.go
index c327d1b43..41faae93e 100644
--- a/core/vm/sqlvm/errors/errors.go
+++ b/core/vm/sqlvm/errors/errors.go
@@ -108,7 +108,6 @@ const (
 	ErrorCodeInvalidUfixedSize
 	ErrorCodeInvalidFixedFractionalDigits
 	ErrorCodeInvalidUfixedFractionalDigits
-	ErrorCodeDataTypeEncode
 	ErrorCodeDataTypeDecode
 	ErrorCodeDecimalEncode
 	ErrorCodeDecimalDecode
@@ -142,7 +141,6 @@ var errorCodeMap = [...]string{
 	ErrorCodeInvalidUfixedSize:             "invalid ufixed size",
 	ErrorCodeInvalidFixedFractionalDigits:  "invalid fixed fractional digits",
 	ErrorCodeInvalidUfixedFractionalDigits: "invalid ufixed fractional digits",
-	ErrorCodeDataTypeEncode:                "data type encode failed",
 	ErrorCodeDataTypeDecode:                "data type decode failed",
 	ErrorCodeDecimalEncode:                 "decimal encode failed",
 	ErrorCodeDecimalDecode:                 "decimal decode failed",