implement the makeHandler and structure the high-level mvc's API

Former-commit-id: 412118eae436981711ef57821f2d85b77a5d1a12

mvc2/binder.go

@@ -10,6 +10,10 @@ import (
 // and a function which will accept a context and returns a value of something.
 type InputBinder struct {
 	BindType reflect.Type
+	// ctx is slice because all binder functions called by
+	// their `.Call` method which accepts a slice of reflect.Value,
+	// so on the handler maker we will allocate a slice of a single ctx once
+	// and used to all binders.
 	BindFunc func(ctx []reflect.Value) reflect.Value
 }
 
@@ -27,6 +31,17 @@ func getBindersForInput(binders []*InputBinder, expected ...reflect.Type) map[in
 	var m map[int]*InputBinder
 
 	for idx, in := range expected {
+		if idx == 0 && isContext(in) {
+			// if the first is context then set it directly here.
+			m = make(map[int]*InputBinder)
+			m[0] = &InputBinder{
+				BindType: contextTyp,
+				BindFunc: func(ctxValues []reflect.Value) reflect.Value {
+					return ctxValues[0]
+				},
+			}
+			continue
+		}
 		for _, b := range binders {
 			// if same type or the result of binder implements the expected in's type.
 			if equalTypes(b.BindType, in) {

mvc2/handler.go

@@ -4,13 +4,21 @@ import (
 	"fmt"
 	"reflect"
 
+	"github.com/kataras/golog"
 	"github.com/kataras/iris/context"
+	"github.com/kataras/iris/mvc/activator/methodfunc"
 )
 
 // checks if "handler" is context.Handler; func(context.Context).
-func isContextHandler(handler interface{}) bool {
-	_, is := handler.(context.Handler)
-	return is
+func isContextHandler(handler interface{}) (context.Handler, bool) {
+	h, is := handler.(context.Handler)
+	if !is {
+		fh, is := handler.(func(context.Context))
+		if is {
+			return fh, is
+		}
+	}
+	return h, is
 }
 
 func validateHandler(handler interface{}) error {
@@ -19,3 +27,58 @@ func validateHandler(handler interface{}) error {
 	}
 	return nil
 }
+
+var (
+	contextTyp = reflect.TypeOf(context.NewContext(nil))
+	emptyIn    = []reflect.Value{}
+)
+
+func makeHandler(handler interface{}, binders []*InputBinder) context.Handler {
+	if err := validateHandler(handler); err != nil {
+		golog.Errorf("mvc handler: %v", err)
+		return nil
+	}
+
+	if h, is := isContextHandler(handler); is {
+		golog.Warnf("mvc handler: you could just use the low-level API to register a context handler instead")
+		return h
+	}
+
+	typ := indirectTyp(reflect.TypeOf(handler))
+	n := typ.NumIn()
+	typIn := make([]reflect.Type, n, n)
+	for i := 0; i < n; i++ {
+		typIn[i] = typ.In(i)
+	}
+
+	m := getBindersForInput(binders, typIn...)
+	if len(m) != n {
+		golog.Errorf("mvc handler: input arguments length(%d) and valid binders length(%d) are not equal", n, len(m))
+		return nil
+	}
+
+	hasIn := len(m) > 0
+	fn := reflect.ValueOf(handler)
+
+	return func(ctx context.Context) {
+		if !hasIn {
+			methodfunc.DispatchFuncResult(ctx, fn.Call(emptyIn))
+			return
+		}
+
+		// we could use other tricks for "in"
+		// here but let's stick to that which is clearly
+		// that it doesn't keep any previous state
+		// and it allocates exactly what we need,
+		// so we can set via index instead of append.
+		// The other method we could use is to
+		// declare the in on the build state (before the return)
+		// and use in[0:0] with append later on.
+		in := make([]reflect.Value, n, n)
+		ctxValues := []reflect.Value{reflect.ValueOf(ctx)}
+		for k, v := range m {
+			in[k] = v.BindFunc(ctxValues)
+		}
+		methodfunc.DispatchFuncResult(ctx, fn.Call(in))
+	}
+}

mvc2/handler_test.go

@@ -0,0 +1,11 @@
+package mvc2
+
+/*
+TODO:
+
+Test that as we test the rest, with
+a fake context, and after move again to
+the mvc_test.go which will contain
+the overall high-level (black-box) tests.
+
+*/

mvc2/mvc.go

@@ -2,6 +2,8 @@ package mvc2
 
 import (
 	"errors"
+
+	"github.com/kataras/iris/context"
 )
 
 var (
@@ -9,3 +11,39 @@ var (
 	errBad           = errors.New("bad")
 	errAlreadyExists = errors.New("already exists")
 )
+
+type Mvc struct {
+	binders []*InputBinder
+}
+
+func New() *Mvc {
+	return new(Mvc)
+}
+
+func (m *Mvc) RegisterBinder(binders ...interface{}) error {
+	for _, binder := range binders {
+		b, err := MakeFuncInputBinder(binder)
+		if err != nil {
+			return err
+		}
+		m.binders = append(m.binders, b)
+	}
+
+	return nil
+}
+
+func (m *Mvc) RegisterService(services ...interface{}) error {
+	for _, service := range services {
+		b, err := MakeServiceInputBinder(service)
+		if err != nil {
+			return err
+		}
+		m.binders = append(m.binders, b)
+	}
+
+	return nil
+}
+
+func (m *Mvc) Handler(handler interface{}) context.Handler {
+	return makeHandler(handler, m.binders)
+}

mvc2/mvc_test.go

@@ -0,0 +1,30 @@
+package mvc2_test
+
+import (
+	"testing"
+
+	"github.com/kataras/iris"
+	"github.com/kataras/iris/httptest"
+	"github.com/kataras/iris/mvc2"
+)
+
+var (
+	lowLevelHandler = func(ctx iris.Context) {
+		ctx.Writef("low-level handler")
+	}
+)
+
+func TestHandler(t *testing.T) {
+	app := iris.New()
+	m := mvc2.New()
+
+	// should just return a context.Handler
+	// without performance penalties.
+	app.Get("/", m.Handler(lowLevelHandler))
+
+	e := httptest.New(t, app, httptest.LogLevel("debug"))
+	// 1
+	e.GET("/").Expect().Status(httptest.StatusOK).
+		Body().Equal("low-level handler")
+
+}