// MagicApplier wraps the function type recieved applying any magic for the
// expected types, returning a SubApplier to call the functions as needed.
func MagicApplier(handle interface{}) SubApplier {
switch handle.(type) {
case func(context.Context, interface{}, interface{}) (interface{}, error):
return handle.(func(context.Context, interface{}, interface{}) (interface{}, error))
case func(interface{}, interface{}) (interface{}, error):
hl := handle.(func(interface{}, interface{}) (interface{}, error))
return func(_ context.Context, d1 interface{}, d2 interface{}) (interface{}, error) {
return hl(d1, d2)
}
default:
if !reflection.IsFuncType(handle) {
return nil
}
tm, _ := reflection.FuncValue(handle)
args, _ := reflection.GetFuncArgumentsType(handle)
dLen := len(args)
if dLen < 2 {
return nil
}
var useContext bool
var useOne bool
var d1 reflect.Type
var d2 reflect.Type
var d1Zero reflect.Value
var d2Zero reflect.Value
if dLen == 2 {
useContext, _ = reflection.CanSetForType(ctxType, args[0])
if useContext {
d1 = args[1]
d1Zero = reflect.Zero(d1)
useOne = true
} else {
d1 = args[0]
d1Zero = reflect.Zero(d1)
d2 = args[1]
d2Zero = reflect.Zero(d2)
}
}
if dLen > 2 {
useContext, _ = reflection.CanSetForType(ctxType, args[0])
if !useContext {
return nil
}
d1 = args[0]
d1Zero = reflect.Zero(d1)
d2 = args[1]
d2Zero = reflect.Zero(d2)
}
return func(ctx context.Context, dl interface{}, rl interface{}) (interface{}, error) {
var fnArgs []reflect.Value
var resArgs []reflect.Value
if useContext {
fnArgs = append(fnArgs, reflect.ValueOf(ctx))
}
var dv1 reflect.Value
var dv2 reflect.Value
if dl != nil {
dv1 = reflect.ValueOf(dl)
} else {
dv1 = d1Zero
}
if rl != nil {
dv2 = reflect.ValueOf(rl)
} else {
dv2 = d2Zero
}
if !useOne {
can, convert := reflection.CanSetFor(d1, dv1)
if !can {
return nil, ErrInvalidType
}
can2, convert2 := reflection.CanSetFor(d2, dv2)
if !can2 {
return nil, ErrInvalidType
}
if convert {
dv1 = dv1.Convert(d1)
}
if convert2 {
dv2 = dv2.Convert(d2)
}
fnArgs = append(fnArgs, dv1, dv2)
resArgs = tm.Call(fnArgs)
resLen := len(resArgs)
// If it has no return, by logic, this is a secondary lift, hence
// return the first argument.
if resLen < 1 {
return dl, nil
}
if resLen < 2 {
rOnly := resArgs[0]
if erErr, ok := rOnly.Interface().(error); ok {
return nil, erErr
}
return rOnly.Interface(), nil
}
rData := resArgs[0].Interface()
rErr := resArgs[1].Interface()
if erErr, ok := rErr.(error); ok {
return rData, erErr
}
return rData, nil
}
var useFirst bool
can, convert := reflection.CanSetFor(d1, dv1)
if can {
useFirst = true
if convert {
dv1 = dv1.Convert(d1)
}
if useFirst {
fnArgs = append(fnArgs, dv1)
}
}
if !useFirst {
can, convert = reflection.CanSetFor(d2, dv2)
if !can {
return nil, errors.New("Invalid Type Recieved")
}
if can && convert {
dv2 = dv2.Convert(d2)
}
fnArgs = append(fnArgs, dv2)
}
resArgs = tm.Call(fnArgs)
resLen := len(resArgs)
// If it has no return, by logic, this is a secondary lift, hence
// return the first argument.
if resLen < 1 {
return dl, nil
}
if resLen < 2 {
rOnly := resArgs[0]
if erErr, ok := rOnly.Interface().(error); ok {
return nil, erErr
}
return rOnly.Interface(), nil
}
rData := resArgs[0].Interface()
rErr := resArgs[1].Interface()
if erErr, ok := rErr.(error); ok {
return rData, erErr
}
return rData, nil
}
}
}
// Wrap returns a new Handler wrapping the provided value as needed if
// it matches its DataHandler, ErrorHandler, Handler or magic function type.
// MagicFunction type is a function which follows this type form:
// func(context.Context, error, <CustomType>).
func Wrap(node interface{}) Handler {
var hl Handler
switch mh := node.(type) {
case Handler:
hl = node.(Handler)
case func():
hl = func(ctx context.Context, err error, d interface{}) (interface{}, error) {
node.(func())()
if err != nil {
return nil, err
}
return d, err
}
case func(context.Context, error, interface{}) (interface{}, error):
hl = node.(func(context.Context, error, interface{}) (interface{}, error))
case func(context.Context, interface{}):
hl = wrapDataWithNoReturn(node.(func(context.Context, interface{})))
case func(context.Context, interface{}) interface{}:
hl = wrapDataWithReturn(node.(func(context.Context, interface{}) interface{}))
case func(context.Context, interface{}) (interface{}, error):
hl = wrapData(node.(func(context.Context, interface{}) (interface{}, error)))
case func(context.Context, error) (interface{}, error):
hl = wrapError(node.(func(context.Context, error) (interface{}, error)))
case func(context.Context, error):
hl = func(ctx context.Context, err error, d interface{}) (interface{}, error) {
if err != nil {
node.(func(context.Context, error))(ctx, err)
}
return d, err
}
case func(context.Context, error) error:
hl = func(ctx context.Context, err error, d interface{}) (interface{}, error) {
if err != nil {
(node.(func(context.Context, error)))(ctx, err)
}
return d, err
}
case func(interface{}) (interface{}, error):
hl = func(ctx context.Context, err error, d interface{}) (interface{}, error) {
if err != nil {
return nil, err
}
return mh(d)
}
case func(interface{}) interface{}:
hl = wrapDataOnly(node.(func(interface{}) interface{}))
case func(interface{}):
hl = wrapJustData(node.(func(interface{})))
case func(error):
hl = wrapJustError(node.(func(error)))
case func(error) error:
hl = wrapErrorReturn(node.(func(error) error))
case func() interface{}:
hl = wrapNoData(node.(func() interface{}))
case func(interface{}) error:
hl = wrapErrorOnly(node.(func(interface{}) error))
default:
if !reflection.IsFuncType(node) {
return nil
}
tm, _ := reflection.FuncValue(node)
args, _ := reflection.GetFuncArgumentsType(node)
dLen := len(args)
var data reflect.Type
var dZero reflect.Value
var useContext bool
var useErr bool
var useData bool
var isCustom bool
// Check if this first item is a context.Context type.
if dLen < 2 {
useContext, _ = reflection.CanSetForType(ctxType, args[0])
useErr, _ = reflection.CanSetForType(errorType, args[0])
if !useErr {
data = args[0]
dZero = reflect.Zero(data)
useData = true
isCustom = true
}
}
if dLen == 2 {
useContext, _ = reflection.CanSetForType(ctxType, args[0])
useErr, _ = reflection.CanSetForType(errorType, args[1])
if !useErr {
data = args[1]
dZero = reflect.Zero(data)
useData = true
isCustom = true
}
}
if dLen > 2 {
useContext, _ = reflection.CanSetForType(ctxType, args[0])
useErr, _ = reflection.CanSetForType(errorType, args[1])
data = args[2]
dZero = reflect.Zero(data)
useData = true
if !useContext || !useData || !useErr {
return nil
}
}
if !useData && !useErr {
return nil
}
hl = func(ctx context.Context, err error, val interface{}) (interface{}, error) {
var fnArgs []reflect.Value
var resArgs []reflect.Value
var mctx reflect.Value
me := dZeroError
md := dZero
if useContext {
mctx = reflect.ValueOf(ctx)
}
if err != nil {
me = reflect.ValueOf(err)
}
// Flag to skip function if data does not match.
breakOfData := true
if val != nil && useData {
ok, convertData := reflection.CanSetForType(data, reflect.TypeOf(val))
if ok {
breakOfData = false
md = reflect.ValueOf(val)
if convertData {
md = md.Convert(data)
}
}
}
if !useContext && !useData && !useErr {
resArgs = tm.Call(nil)
} else {
if isCustom && !useErr && err != nil {
return nil, err
}
if !useContext && !useData && useErr && err != nil {
return nil, err
}
if useContext && !useData && useErr && err != nil {
return nil, err
}
// Call the function if it only cares about the error
if useContext && useErr && me != dZeroError && !useData {
fnArgs = []reflect.Value{mctx, me}
}
// If data does not match then skip this fall.
if breakOfData && len(fnArgs) < 1 {
return nil, ErrInvalidType
}
if !breakOfData {
if useContext && useErr && useData {
fnArgs = []reflect.Value{mctx, me, md}
}
if useContext && !useErr && useData {
fnArgs = []reflect.Value{mctx, md}
}
if !useContext && useData && useErr {
fnArgs = []reflect.Value{me, md}
}
if !useContext && useData && !useErr {
fnArgs = []reflect.Value{md}
}
}
resArgs = tm.Call(fnArgs)
}
resLen := len(resArgs)
if resLen > 0 {
if resLen < 2 {
rOnly := resArgs[0]
if erErr, ok := rOnly.Interface().(error); ok {
return nil, erErr
}
return rOnly.Interface(), nil
}
rData := resArgs[0].Interface()
rErr := resArgs[1].Interface()
if erErr, ok := rErr.(error); ok {
return rData, erErr
}
return rData, nil
}
return dZero, nil
}
}
return hl
}
// WrapStreamHandler wraps a handler returning a StreamHandler.
func WrapStreamHandler(h interface{}) StreamHandler {
switch h.(type) {
case func(context.Context, error, interface{}) (interface{}, error):
return func(ctx context.Context, data interface{}, end bool) interface{} {
if ed, ok := data.(error); ok {
res, err := (h.(func(context.Context, error, interface{}) (interface{}, error)))(ctx, ed, nil)
if err != nil {
return err
}
return res
}
res, err := (h.(func(context.Context, error, interface{}) (interface{}, error)))(ctx, nil, data)
if err != nil {
return err
}
return res
}
case func(context.Context, interface{}, bool) interface{}:
return h.(func(context.Context, interface{}, bool) interface{})
default:
if !reflection.IsFuncType(h) {
return nil
}
tm, _ := reflection.FuncValue(h)
args, _ := reflection.GetFuncArgumentsType(h)
dLen := len(args)
var data reflect.Type
var dZero reflect.Value
var useContext bool
var useBool bool
var useData bool
// var isCustom bool
// Check if this first item is a context.Context type.
if dLen < 2 {
useContext, _ = reflection.CanSetForType(ctxType, args[0])
useBool, _ = reflection.CanSetForType(boolType, args[0])
if !useBool {
data = args[0]
dZero = reflect.Zero(data)
useData = true
// isCustom = true
}
}
if dLen == 2 {
useContext, _ = reflection.CanSetForType(ctxType, args[0])
useBool, _ = reflection.CanSetForType(boolType, args[1])
if !useBool {
data = args[1]
dZero = reflect.Zero(data)
useData = true
// isCustom = true
}
}
if dLen > 2 {
useContext, _ = reflection.CanSetForType(ctxType, args[0])
useBool, _ = reflection.CanSetForType(boolType, args[2])
data = args[1]
dZero = reflect.Zero(data)
useData = true
}
return func(ctx context.Context, val interface{}, done bool) interface{} {
var fnArgs []reflect.Value
var resArgs []reflect.Value
var mctx reflect.Value
me := reflect.ValueOf(done)
md := dZero
if useContext {
mctx = reflect.ValueOf(ctx)
}
// Flag to skip function if data does not match.
breakOfData := true
if val != nil && useData {
ok, convertData := reflection.CanSetForType(data, reflect.TypeOf(val))
if ok {
breakOfData = false
md = reflect.ValueOf(val)
if convertData {
md = md.Convert(data)
}
}
}
if !useContext && !useData && !useBool {
resArgs = tm.Call(nil)
} else {
// If data does not match then skip this fall.
if breakOfData && len(fnArgs) < 1 {
return nil
}
if !breakOfData {
if useContext && useBool && useData {
fnArgs = []reflect.Value{mctx, md, me}
}
if useContext && !useBool && useData {
fnArgs = []reflect.Value{mctx, md}
}
if !useContext && useData && useBool {
fnArgs = []reflect.Value{md, me}
}
if !useContext && useData && !useBool {
fnArgs = []reflect.Value{md}
}
}
resArgs = tm.Call(fnArgs)
}
resLen := len(resArgs)
if resLen < 1 {
return nil
}
return resArgs[0].Interface()
}
}
}