fix: unittests for CallFunc

plugin/shared/call.go

@@ -3,24 +3,97 @@ package shared
 import (
 	"fmt"
 	"reflect"
+
+	"github.com/rs/zerolog/log"
 )
 
 // CallFunc calls function with arguments
 // it is used when calling go plugin or builtin functions
 func CallFunc(fn reflect.Value, args ...interface{}) (interface{}, error) {
 	fnArgsNum := fn.Type().NumIn()
-	if fnArgsNum > 0 && fn.Type().In(fnArgsNum-1).Kind() == reflect.Slice {
-		// last argument is slice, do not check arguments number
-		// e.g. ...interface{}
-		// e.g. a, b string, c ...interface{}
-	} else if fnArgsNum != len(args) {
-		// function arguments not match
-		return nil, fmt.Errorf("function arguments number not match, expect %d, got %d", fnArgsNum, len(args))
-	}
-	// arguments do not have slice, and arguments number matched
 
-	argumentsValue := make([]reflect.Value, len(args))
-	for index, argument := range args {
+	// function expect 0 argument
+	if fnArgsNum == 0 {
+		if len(args) > 0 {
+			return nil, fmt.Errorf("function expect 0 argument, but got %d", len(args))
+		}
+		return call(fn, nil)
+	}
+
+	// fnArgsNum > 0: function expect more than 0 arguments
+	// function last argument is not slice
+	if fn.Type().In(fnArgsNum-1).Kind() != reflect.Slice {
+		// function arguments should match exactly
+		if fnArgsNum != len(args) {
+			return nil, fmt.Errorf("function expect %d arguments, but got %d", fnArgsNum, len(args))
+		}
+		// prepare arguments
+		argumentsValue, err := convertFirstNArgs(fn, fnArgsNum, args...)
+		if err != nil {
+			return nil, err
+		}
+		return call(fn, argumentsValue)
+	}
+
+	// function last argument is slice
+	// e.g.
+	// ...interface{}
+	// a, b string, c ...interface{}
+	// []int
+	// a, b string, c []int
+
+	// arguments number should >= fnArgsNum-1
+	if len(args) < fnArgsNum-1 {
+		return nil, fmt.Errorf("function expect at least %d arguments, but got %d", fnArgsNum-1, len(args))
+	}
+
+	// prepare first n-1 arguments
+	argumentsValue, err := convertFirstNArgs(fn, fnArgsNum-1, args...)
+	if err != nil {
+		return nil, err
+	}
+
+	// prepare last slice argument
+	fnLastSliceElemType := fn.Type().In(fnArgsNum - 1).Elem() // slice element type
+	for i := fnArgsNum - 1; i < len(args); i++ {              // loop last len(args)-fnArgsNum+1 arguments
+		argValue := reflect.ValueOf(args[i])
+		argValueType := reflect.TypeOf(args[i])
+
+		// check if slice element type match
+		if fnLastSliceElemType == argValueType {
+			argumentsValue = append(argumentsValue, argValue)
+			continue
+		}
+
+		// last argument is also slice, e.g. []int
+		if argValueType.Kind() == reflect.Slice {
+			if argValueType.Elem() != fnLastSliceElemType {
+				err := fmt.Errorf("function argument %d's slice element type is not match, expect %v, actual %v",
+					i, fnLastSliceElemType, argValueType)
+				return nil, err
+			}
+			argumentsValue = append(argumentsValue, argValue)
+			continue
+		}
+
+		// type not match, check if convertible
+		if !argValueType.ConvertibleTo(fnLastSliceElemType) {
+			// function argument type not match and not convertible
+			err := fmt.Errorf("function argument %d's type is neither match nor convertible, expect %v, actual %v",
+				i, fnLastSliceElemType, argValueType)
+			return nil, err
+		}
+		// convert argument to expect type
+		argumentsValue = append(argumentsValue, argValue.Convert(fnLastSliceElemType))
+	}
+
+	return call(fn, argumentsValue)
+}
+
+func convertFirstNArgs(fn reflect.Value, n int, args ...interface{}) ([]reflect.Value, error) {
+	argumentsValue := make([]reflect.Value, n)
+	for index := 0; index < n; index++ {
+		argument := args[index]
 		if argument == nil {
 			argumentsValue[index] = reflect.Zero(fn.Type().In(index))
 			continue
@@ -41,13 +114,17 @@ func CallFunc(fn reflect.Value, args ...interface{}) (interface{}, error) {
 			// function argument type not match and not convertible
 			err := fmt.Errorf("function argument %d's type is neither match nor convertible, expect %v, actual %v",
 				index, expectArgumentType, actualArgumentType)
+			log.Error().Err(err).Msg("convert arguments failed")
 			return nil, err
 		}
 		// convert argument to expect type
 		argumentsValue[index] = argumentValue.Convert(expectArgumentType)
 	}
+	return argumentsValue, nil
+}
 
-	resultValues := fn.Call(argumentsValue)
+func call(fn reflect.Value, args []reflect.Value) (interface{}, error) {
+	resultValues := fn.Call(args)
 	if resultValues == nil {
 		// no returns
 		return nil, nil
@@ -69,7 +146,7 @@ func CallFunc(fn reflect.Value, args ...interface{}) (interface{}, error) {
 		}
 	} else {
 		// return more than 2 arguments, unexpected
-		err := fmt.Errorf("function should return at most 2 arguments")
+		err := fmt.Errorf("function should return at most 2 values")
 		return nil, err
 	}
 }

plugin/shared/call_test.go

@@ -9,13 +9,14 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-func TestCallFunc(t *testing.T) {
-	type data struct {
-		f      interface{}
-		args   []interface{}
-		expVal interface{}
-		expErr error
-	}
+type data struct {
+	f      interface{}
+	args   []interface{}
+	expVal interface{}
+	expErr error
+}
+
+func TestCallFuncBasic(t *testing.T) {
 	params := []data{
 		// zero argument, zero return
 		{f: func() {}, args: []interface{}{}, expVal: nil, expErr: nil},
@@ -28,10 +29,16 @@ func TestCallFunc(t *testing.T) {
 		// zero argument, return one value and error
 		{f: func() (int, error) { return 1, errors.New("xxx") }, args: []interface{}{}, expVal: 1, expErr: errors.New("xxx")},
 		{f: func() (interface{}, error) { return 1.23, errors.New("xxx") }, args: []interface{}{}, expVal: 1.23, expErr: errors.New("xxx")},
+
+		// one argument, zero return
+		{f: func(n int) {}, args: []interface{}{1}, expVal: nil, expErr: nil},
 		// one argument, return one value
 		{f: func(n int) int { return n * n }, args: []interface{}{2}, expVal: 4},
 		{f: func(c string) string { return c + c }, args: []interface{}{"p"}, expVal: "pp"},
 		{f: func(arg interface{}) interface{} { return fmt.Sprintf("%v", arg) }, args: []interface{}{1.23}, expVal: "1.23"},
+		// one argument, return one value and error
+		{f: func(arg interface{}) (interface{}, error) { return 1.23, errors.New("xxx") }, args: []interface{}{"a"}, expVal: 1.23, expErr: errors.New("xxx")},
+
 		// two arguments in same type
 		{f: func(a, b int) int { return a * b }, args: []interface{}{2, 3}, expVal: 6},
 		// two arguments in different type
@@ -46,6 +53,123 @@ func TestCallFunc(t *testing.T) {
 			args:   []interface{}{3, "p"},
 			expVal: "ppp",
 		},
+
+		// variable arguments list: ...int, ...interface{}
+		{
+			f: func(n ...int) int {
+				var sum int
+				for _, arg := range n {
+					sum += arg
+				}
+				return sum
+			},
+			args:   []interface{}{1, 2, 3},
+			expVal: 6,
+		},
+		{
+			f: func(args ...interface{}) (interface{}, error) {
+				var result string
+				for _, arg := range args {
+					result += fmt.Sprintf("%v", arg)
+				}
+				return result, nil
+			},
+			args:   []interface{}{1, 2.3, "4.5", "p"},
+			expVal: "12.34.5p",
+		},
+		{
+			f: func(a, b int8, n ...int) int {
+				var sum int
+				for _, arg := range n {
+					sum += arg
+				}
+				sum += int(a) + int(b)
+				return sum
+			},
+			args:   []interface{}{1, 2, 3, 4.5},
+			expVal: 10,
+		},
+		{
+			f: func(a, b int8, n ...int) int {
+				sum := int(a) + int(b)
+				for _, arg := range n {
+					sum += arg
+				}
+				return sum
+			},
+			args:   []interface{}{1, 2},
+			expVal: 3,
+		},
+
+		{
+			f: func(a []int, n ...int) int {
+				var sum int
+				for _, arg := range a {
+					sum += arg
+				}
+				for _, arg := range n {
+					sum += arg
+				}
+				return sum
+			},
+			args:   []interface{}{[]int{1, 2}, 3, 4},
+			expVal: 10,
+		},
+	}
+
+	for _, p := range params {
+		fn := reflect.ValueOf(p.f)
+		val, err := CallFunc(fn, p.args...)
+		if !assert.Equal(t, p.expErr, err) {
+			t.Fatal(err)
+		}
+		if !assert.Equal(t, p.expVal, val) {
+			t.Fatal()
+		}
+	}
+
+}
+
+func TestCallFuncComplex(t *testing.T) {
+	params := []data{
+		// arguments include slice
+		{
+			f: func(a int, n []int, b int) int {
+				sum := a
+				for _, arg := range n {
+					sum += arg
+				}
+				sum += b
+				return sum
+			},
+			args:   []interface{}{1, []int{2, 3}, 4},
+			expVal: 10,
+		},
+		// last argument is slice
+		{
+			f: func(n []int) int {
+				var sum int
+				for _, arg := range n {
+					sum += arg
+				}
+				return sum
+			},
+			args:   []interface{}{[]int{1, 2, 3}},
+			expVal: 6,
+		},
+		{
+			f: func(a, b int, n []int) int {
+				sum := a + b
+				for _, arg := range n {
+					sum += arg
+				}
+				return sum
+			},
+			args:   []interface{}{1, 2, []int{3, 4}},
+			expVal: 10,
+		},
+
+		// FIXME: return more than 2 values
 	}
 
 	for _, p := range params {