diff options
author | Unknwon <u@gogs.io> | 2017-02-09 19:48:13 -0500 |
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committer | Unknwon <u@gogs.io> | 2017-02-09 19:48:13 -0500 |
commit | 2fd69f13d9599a6c58b47225565163fd7d87889f (patch) | |
tree | fd19e868e1c2e95a5fb83a268f6e393669d6ee79 /vendor/github.com/go-macaron/inject/inject.go | |
parent | eb66060cd7b9bce996b1d75ae80ce1ef31d5ce62 (diff) |
vendor: check in vendors
Bye bye glide...
Diffstat (limited to 'vendor/github.com/go-macaron/inject/inject.go')
-rw-r--r-- | vendor/github.com/go-macaron/inject/inject.go | 262 |
1 files changed, 262 insertions, 0 deletions
diff --git a/vendor/github.com/go-macaron/inject/inject.go b/vendor/github.com/go-macaron/inject/inject.go new file mode 100644 index 00000000..1c1f98ea --- /dev/null +++ b/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 +} |