Merge branch 'matijavizintin-better-error-handling'

Author: buger

parser.go

@@ -9,6 +9,17 @@ import (
 	"unsafe"
 )
 
+// Errors
+var (
+	KeyPathNotFoundError = errors.New("Key path not found")
+	UnknownValueTypeError = errors.New("Unknown value type")
+	MalformedJsonError = errors.New("Malformed JSON error")
+	MalformedStringError = errors.New("Value is string, but can't find closing '\"' symbol")
+	MalformedArrayError = errors.New("Value is array, but can't find closing ']' symbol")
+	MalformedObjectError = errors.New("Value looks like object, but can't find closing '}' symbol")
+	MalformedValueError = errors.New("Value looks like Number/Boolean/None, but can't find its end: ',' or '}' symbol")
+)
+
 func tokenEnd(data []byte) int {
 	for i, c := range data {
 		switch c {
@@ -186,15 +197,15 @@ If no keys provided it will try to extract closest JSON value (simple ones or ob
 func Get(data []byte, keys ...string) (value []byte, dataType ValueType, offset int, err error) {
 	if len(keys) > 0 {
 		if offset = searchKeys(data, keys...); offset == -1 {
-			return []byte{}, NotExist, -1, errors.New("Key path not found")
+			return []byte{}, NotExist, -1, KeyPathNotFoundError
 		}
 	}
 
 	// Go to closest value
 	nO := nextToken(data[offset:], false)
 
 	if nO == -1 {
-		return []byte{}, NotExist, -1, errors.New("Malformed JSON error")
+		return []byte{}, NotExist, -1, MalformedJsonError
 	}
 
 	offset += nO
@@ -206,15 +217,15 @@ func Get(data []byte, keys ...string) (value []byte, dataType ValueType, offset
 		if idx := stringEnd(data[offset+1:]); idx != -1 {
 			endOffset += idx + 1
 		} else {
-			return []byte{}, dataType, offset, errors.New("Value is string, but can't find closing '\"' symbol")
+			return []byte{}, dataType, offset, MalformedStringError
 		}
 	} else if data[offset] == '[' { // if array value
 		dataType = Array
 		// break label, for stopping nested loops
 		endOffset = blockEnd(data[offset:], '[', ']')
 
 		if endOffset == -1 {
-			return []byte{}, dataType, offset, errors.New("Value is array, but can't find closing ']' symbol")
+			return []byte{}, dataType, offset, MalformedArrayError
 		}
 
 		endOffset += offset
@@ -224,7 +235,7 @@ func Get(data []byte, keys ...string) (value []byte, dataType ValueType, offset
 		endOffset = blockEnd(data[offset:], '{', '}')
 
 		if endOffset == -1 {
-			return []byte{}, dataType, offset, errors.New("Value looks like object, but can't find closing '}' symbol")
+			return []byte{}, dataType, offset, MalformedObjectError
 		}
 
 		endOffset += offset
@@ -233,7 +244,7 @@ func Get(data []byte, keys ...string) (value []byte, dataType ValueType, offset
 		end := tokenEnd(data[endOffset:])
 
 		if end == -1 {
-			return nil, dataType, offset, errors.New("Value looks like Number/Boolean/None, but can't find its end: ',' or '}' symbol")
+			return nil, dataType, offset, MalformedValueError
 		}
 
 		value := data[offset : endOffset+end]
@@ -243,18 +254,18 @@ func Get(data []byte, keys ...string) (value []byte, dataType ValueType, offset
 			if bytes.Equal(value, trueLiteral) || bytes.Equal(value, falseLiteral) {
 				dataType = Boolean
 			} else {
-				return nil, Unknown, offset, errors.New("Unknown value type")
+				return nil, Unknown, offset, UnknownValueTypeError
 			}
 		case 'u', 'n': // undefined or null
 			if bytes.Equal(value, nullLiteral) {
 				dataType = Null
 			} else {
-				return nil, Unknown, offset, errors.New("Unknown value type")
+				return nil, Unknown, offset, UnknownValueTypeError
 			}
 		case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '-':
 			dataType = Number
 		default:
-			return nil, Unknown, offset, errors.New("Unknown value type")
+			return nil, Unknown, offset, UnknownValueTypeError
 		}
 
 		endOffset += end
@@ -277,27 +288,27 @@ func Get(data []byte, keys ...string) (value []byte, dataType ValueType, offset
 // ArrayEach is used when iterating arrays, accepts a callback function with the same return arguments as `Get`.
 func ArrayEach(data []byte, cb func(value []byte, dataType ValueType, offset int, err error), keys ...string) (err error) {
 	if len(data) == 0 {
-		return errors.New("Object is empty")
+		return MalformedObjectError
 	}
 
 	offset := 1
 
 	if len(keys) > 0 {
 		if offset = searchKeys(data, keys...); offset == -1 {
-			return errors.New("Key path not found")
+			return KeyPathNotFoundError
 		}
 
 		// Go to closest value
 		nO := nextToken(data[offset:], false)
 
 		if nO == -1 {
-			return errors.New("Malformed JSON")
+			return MalformedJsonError
 		}
 
 		offset += nO
 
 		if data[offset] != '[' {
-			return errors.New("Value is not array")
+			return MalformedArrayError
 		}
 
 		offset++

parser_test.go

@@ -418,6 +418,10 @@ func checkFoundAndNoError(t *testing.T, testKind string, test Test, jtype ValueT
 		// Else, if the call didn't match the is-found expectation, fail
 		t.Errorf("%s test '%s' isFound mismatch: expected %t, obtained %t", testKind, test.desc, test.isFound, isFound)
 		return false
+	} else if !isFound && err != KeyPathNotFoundError {
+		// Else, if no value was found and the error is not correct, fail
+		t.Errorf("%s test '%s' error mismatch: expected %t, obtained %t", testKind, test.desc, KeyPathNotFoundError, err)
+		return false
 	} else if !isFound {
 		// Else, if no value was found, don't fail and don't check the value
 		return false