Added all required dependencies

vendor/github.com/go-macaron/inject/inject.go

@@ -0,0 +1,262 @@
+// Copyright 2013 Jeremy Saenz
+// Copyright 2015 The Macaron Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License"): you may
+// not use this file except in compliance with the License. You may obtain
+// a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+// License for the specific language governing permissions and limitations
+// under the License.
+
+// Package inject provides utilities for mapping and injecting dependencies in various ways.
+package inject
+
+import (
+	"fmt"
+	"reflect"
+)
+
+// Injector represents an interface for mapping and injecting dependencies into structs
+// and function arguments.
+type Injector interface {
+	Applicator
+	Invoker
+	TypeMapper
+	// SetParent sets the parent of the injector. If the injector cannot find a
+	// dependency in its Type map it will check its parent before returning an
+	// error.
+	SetParent(Injector)
+}
+
+// Applicator represents an interface for mapping dependencies to a struct.
+type Applicator interface {
+	// Maps dependencies in the Type map to each field in the struct
+	// that is tagged with 'inject'. Returns an error if the injection
+	// fails.
+	Apply(interface{}) error
+}
+
+// Invoker represents an interface for calling functions via reflection.
+type Invoker interface {
+	// Invoke attempts to call the interface{} provided as a function,
+	// providing dependencies for function arguments based on Type. Returns
+	// a slice of reflect.Value representing the returned values of the function.
+	// Returns an error if the injection fails.
+	Invoke(interface{}) ([]reflect.Value, error)
+}
+
+// FastInvoker represents an interface in order to avoid the calling function via reflection.
+//
+// example:
+//	type handlerFuncHandler func(http.ResponseWriter, *http.Request) error
+//	func (f handlerFuncHandler)Invoke([]interface{}) ([]reflect.Value, error){
+//		ret := f(p[0].(http.ResponseWriter), p[1].(*http.Request))
+//		return []reflect.Value{reflect.ValueOf(ret)}, nil
+//	}
+//
+//	type funcHandler func(int, string)
+//	func (f funcHandler)Invoke([]interface{}) ([]reflect.Value, error){
+//		f(p[0].(int), p[1].(string))
+//		return nil, nil
+//	}
+type FastInvoker interface {
+	// Invoke attempts to call the ordinary functions. If f is a function
+	// with the appropriate signature, f.Invoke([]interface{}) is a Call that calls f.
+	// Returns a slice of reflect.Value representing the returned values of the function.
+	// Returns an error if the injection fails.
+	Invoke([]interface{}) ([]reflect.Value, error)
+}
+
+// IsFastInvoker check interface is FastInvoker
+func IsFastInvoker(h interface{}) bool {
+	_, ok := h.(FastInvoker)
+	return ok
+}
+
+// TypeMapper represents an interface for mapping interface{} values based on type.
+type TypeMapper interface {
+	// Maps the interface{} value based on its immediate type from reflect.TypeOf.
+	Map(interface{}) TypeMapper
+	// Maps the interface{} value based on the pointer of an Interface provided.
+	// This is really only useful for mapping a value as an interface, as interfaces
+	// cannot at this time be referenced directly without a pointer.
+	MapTo(interface{}, interface{}) TypeMapper
+	// Provides a possibility to directly insert a mapping based on type and value.
+	// This makes it possible to directly map type arguments not possible to instantiate
+	// with reflect like unidirectional channels.
+	Set(reflect.Type, reflect.Value) TypeMapper
+	// Returns the Value that is mapped to the current type. Returns a zeroed Value if
+	// the Type has not been mapped.
+	GetVal(reflect.Type) reflect.Value
+}
+
+type injector struct {
+	values map[reflect.Type]reflect.Value
+	parent Injector
+}
+
+// InterfaceOf dereferences a pointer to an Interface type.
+// It panics if value is not an pointer to an interface.
+func InterfaceOf(value interface{}) reflect.Type {
+	t := reflect.TypeOf(value)
+
+	for t.Kind() == reflect.Ptr {
+		t = t.Elem()
+	}
+
+	if t.Kind() != reflect.Interface {
+		panic("Called inject.InterfaceOf with a value that is not a pointer to an interface. (*MyInterface)(nil)")
+	}
+
+	return t
+}
+
+// New returns a new Injector.
+func New() Injector {
+	return &injector{
+		values: make(map[reflect.Type]reflect.Value),
+	}
+}
+
+// Invoke attempts to call the interface{} provided as a function,
+// providing dependencies for function arguments based on Type.
+// Returns a slice of reflect.Value representing the returned values of the function.
+// Returns an error if the injection fails.
+// It panics if f is not a function
+func (inj *injector) Invoke(f interface{}) ([]reflect.Value, error) {
+	t := reflect.TypeOf(f)
+	switch v := f.(type) {
+	case FastInvoker:
+		return inj.fastInvoke(v, t, t.NumIn())
+	default:
+		return inj.callInvoke(f, t, t.NumIn())
+	}
+}
+
+func (inj *injector) fastInvoke(f FastInvoker, t reflect.Type, numIn int) ([]reflect.Value, error) {
+	var in []interface{}
+	if numIn > 0 {
+		in = make([]interface{}, numIn) // Panic if t is not kind of Func
+		var argType reflect.Type
+		var val reflect.Value
+		for i := 0; i < numIn; i++ {
+			argType = t.In(i)
+			val = inj.GetVal(argType)
+			if !val.IsValid() {
+				return nil, fmt.Errorf("Value not found for type %v", argType)
+			}
+
+			in[i] = val.Interface()
+		}
+	}
+	return f.Invoke(in)
+}
+
+// callInvoke reflect.Value.Call
+func (inj *injector) callInvoke(f interface{}, t reflect.Type, numIn int) ([]reflect.Value, error) {
+	var in []reflect.Value
+	if numIn > 0 {
+		in = make([]reflect.Value, numIn)
+		var argType reflect.Type
+		var val reflect.Value
+		for i := 0; i < numIn; i++ {
+			argType = t.In(i)
+			val = inj.GetVal(argType)
+			if !val.IsValid() {
+				return nil, fmt.Errorf("Value not found for type %v", argType)
+			}
+
+			in[i] = val
+		}
+	}
+	return reflect.ValueOf(f).Call(in), nil
+}
+
+// Maps dependencies in the Type map to each field in the struct
+// that is tagged with 'inject'.
+// Returns an error if the injection fails.
+func (inj *injector) Apply(val interface{}) error {
+	v := reflect.ValueOf(val)
+
+	for v.Kind() == reflect.Ptr {
+		v = v.Elem()
+	}
+
+	if v.Kind() != reflect.Struct {
+		return nil // Should not panic here ?
+	}
+
+	t := v.Type()
+
+	for i := 0; i < v.NumField(); i++ {
+		f := v.Field(i)
+		structField := t.Field(i)
+		if f.CanSet() && (structField.Tag == "inject" || structField.Tag.Get("inject") != "") {
+			ft := f.Type()
+			v := inj.GetVal(ft)
+			if !v.IsValid() {
+				return fmt.Errorf("Value not found for type %v", ft)
+			}
+
+			f.Set(v)
+		}
+
+	}
+
+	return nil
+}
+
+// Maps the concrete value of val to its dynamic type using reflect.TypeOf,
+// It returns the TypeMapper registered in.
+func (i *injector) Map(val interface{}) TypeMapper {
+	i.values[reflect.TypeOf(val)] = reflect.ValueOf(val)
+	return i
+}
+
+func (i *injector) MapTo(val interface{}, ifacePtr interface{}) TypeMapper {
+	i.values[InterfaceOf(ifacePtr)] = reflect.ValueOf(val)
+	return i
+}
+
+// Maps the given reflect.Type to the given reflect.Value and returns
+// the Typemapper the mapping has been registered in.
+func (i *injector) Set(typ reflect.Type, val reflect.Value) TypeMapper {
+	i.values[typ] = val
+	return i
+}
+
+func (i *injector) GetVal(t reflect.Type) reflect.Value {
+	val := i.values[t]
+
+	if val.IsValid() {
+		return val
+	}
+
+	// no concrete types found, try to find implementors
+	// if t is an interface
+	if t.Kind() == reflect.Interface {
+		for k, v := range i.values {
+			if k.Implements(t) {
+				val = v
+				break
+			}
+		}
+	}
+
+	// Still no type found, try to look it up on the parent
+	if !val.IsValid() && i.parent != nil {
+		val = i.parent.GetVal(t)
+	}
+
+	return val
+
+}
+
+func (i *injector) SetParent(parent Injector) {
+	i.parent = parent
+}