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| author | Teddy Wing | 2015-06-06 19:25:17 -0400 |
|---|---|---|
| committer | Teddy Wing | 2015-06-06 19:25:17 -0400 |
| commit | 1135764727f3dc525d0f674c784edbc81cc786f3 (patch) | |
| tree | 5c402c88d3a07a3cde84237ead5829bda28f3e25 /vendor/_nuts/github.com/codegangsta/inject/inject.go | |
| download | New-House-on-the-Block-1135764727f3dc525d0f674c784edbc81cc786f3.tar.bz2 | |
Initial commit. Install coinbase-go.
* Use nut for vendored dependencies
* Install coinbase-go to interact with the Coinbase API
Diffstat (limited to 'vendor/_nuts/github.com/codegangsta/inject/inject.go')
| -rw-r--r-- | vendor/_nuts/github.com/codegangsta/inject/inject.go | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/vendor/_nuts/github.com/codegangsta/inject/inject.go b/vendor/_nuts/github.com/codegangsta/inject/inject.go new file mode 100644 index 0000000..3ff713c --- /dev/null +++ b/vendor/_nuts/github.com/codegangsta/inject/inject.go @@ -0,0 +1,187 @@ +// 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) +} + +// 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. + Get(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) + + var in = make([]reflect.Value, t.NumIn()) //Panic if t is not kind of Func + for i := 0; i < t.NumIn(); i++ { + argType := t.In(i) + val := inj.Get(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.Get(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) Get(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.Get(t) + } + + return val + +} + +func (i *injector) SetParent(parent Injector) { + i.parent = parent +} |
