1 files changed, 420 insertions, 0 deletions
diff --git a/vendor/github.com/mitchellh/reflectwalk/reflectwalk.go b/vendor/github.com/mitchellh/reflectwalk/reflectwalk.go
new file mode 100644
index 000000000..7fee7b050
--- /dev/null
+++ b/vendor/github.com/mitchellh/reflectwalk/reflectwalk.go
@@ -0,0 +1,420 @@
+// reflectwalk is a package that allows you to "walk" complex structures
+// similar to how you may "walk" a filesystem: visiting every element one
+// by one and calling callback functions allowing you to handle and manipulate
+// those elements.
+package reflectwalk
+
+import (
+	"errors"
+	"reflect"
+)
+
+// PrimitiveWalker implementations are able to handle primitive values
+// within complex structures. Primitive values are numbers, strings,
+// booleans, funcs, chans.
+//
+// These primitive values are often members of more complex
+// structures (slices, maps, etc.) that are walkable by other interfaces.
+type PrimitiveWalker interface {
+	Primitive(reflect.Value) error
+}
+
+// InterfaceWalker implementations are able to handle interface values as they
+// are encountered during the walk.
+type InterfaceWalker interface {
+	Interface(reflect.Value) error
+}
+
+// MapWalker implementations are able to handle individual elements
+// found within a map structure.
+type MapWalker interface {
+	Map(m reflect.Value) error
+	MapElem(m, k, v reflect.Value) error
+}
+
+// SliceWalker implementations are able to handle slice elements found
+// within complex structures.
+type SliceWalker interface {
+	Slice(reflect.Value) error
+	SliceElem(int, reflect.Value) error
+}
+
+// ArrayWalker implementations are able to handle array elements found
+// within complex structures.
+type ArrayWalker interface {
+	Array(reflect.Value) error
+	ArrayElem(int, reflect.Value) error
+}
+
+// StructWalker is an interface that has methods that are called for
+// structs when a Walk is done.
+type StructWalker interface {
+	Struct(reflect.Value) error
+	StructField(reflect.StructField, reflect.Value) error
+}
+
+// EnterExitWalker implementations are notified before and after
+// they walk deeper into complex structures (into struct fields,
+// into slice elements, etc.)
+type EnterExitWalker interface {
+	Enter(Location) error
+	Exit(Location) error
+}
+
+// PointerWalker implementations are notified when the value they're
+// walking is a pointer or not. Pointer is called for _every_ value whether
+// it is a pointer or not.
+type PointerWalker interface {
+	PointerEnter(bool) error
+	PointerExit(bool) error
+}
+
+// PointerValueWalker implementations are notified with the value of
+// a particular pointer when a pointer is walked. Pointer is called
+// right before PointerEnter.
+type PointerValueWalker interface {
+	Pointer(reflect.Value) error
+}
+
+// SkipEntry can be returned from walk functions to skip walking
+// the value of this field. This is only valid in the following functions:
+//
+//   - Struct: skips all fields from being walked
+//   - StructField: skips walking the struct value
+//
+var SkipEntry = errors.New("skip this entry")
+
+// Walk takes an arbitrary value and an interface and traverses the
+// value, calling callbacks on the interface if they are supported.
+// The interface should implement one or more of the walker interfaces
+// in this package, such as PrimitiveWalker, StructWalker, etc.
+func Walk(data, walker interface{}) (err error) {
+	v := reflect.ValueOf(data)
+	ew, ok := walker.(EnterExitWalker)
+	if ok {
+		err = ew.Enter(WalkLoc)
+	}
+
+	if err == nil {
+		err = walk(v, walker)
+	}
+
+	if ok && err == nil {
+		err = ew.Exit(WalkLoc)
+	}
+
+	return
+}
+
+func walk(v reflect.Value, w interface{}) (err error) {
+	// Determine if we're receiving a pointer and if so notify the walker.
+	// The logic here is convoluted but very important (tests will fail if
+	// almost any part is changed). I will try to explain here.
+	//
+	// First, we check if the value is an interface, if so, we really need
+	// to check the interface's VALUE to see whether it is a pointer.
+	//
+	// Check whether the value is then a pointer. If so, then set pointer
+	// to true to notify the user.
+	//
+	// If we still have a pointer or an interface after the indirections, then
+	// we unwrap another level
+	//
+	// At this time, we also set "v" to be the dereferenced value. This is
+	// because once we've unwrapped the pointer we want to use that value.
+	pointer := false
+	pointerV := v
+
+	for {
+		if pointerV.Kind() == reflect.Interface {
+			if iw, ok := w.(InterfaceWalker); ok {
+				if err = iw.Interface(pointerV); err != nil {
+					return
+				}
+			}
+
+			pointerV = pointerV.Elem()
+		}
+
+		if pointerV.Kind() == reflect.Ptr {
+			if pw, ok := w.(PointerValueWalker); ok {
+				if err = pw.Pointer(pointerV); err != nil {
+					if err == SkipEntry {
+						// Skip the rest of this entry but clear the error
+						return nil
+					}
+
+					return
+				}
+			}
+
+			pointer = true
+			v = reflect.Indirect(pointerV)
+		}
+		if pw, ok := w.(PointerWalker); ok {
+			if err = pw.PointerEnter(pointer); err != nil {
+				return
+			}
+
+			defer func(pointer bool) {
+				if err != nil {
+					return
+				}
+
+				err = pw.PointerExit(pointer)
+			}(pointer)
+		}
+
+		if pointer {
+			pointerV = v
+		}
+		pointer = false
+
+		// If we still have a pointer or interface we have to indirect another level.
+		switch pointerV.Kind() {
+		case reflect.Ptr, reflect.Interface:
+			continue
+		}
+		break
+	}
+
+	// We preserve the original value here because if it is an interface
+	// type, we want to pass that directly into the walkPrimitive, so that
+	// we can set it.
+	originalV := v
+	if v.Kind() == reflect.Interface {
+		v = v.Elem()
+	}
+
+	k := v.Kind()
+	if k >= reflect.Int && k <= reflect.Complex128 {
+		k = reflect.Int
+	}
+
+	switch k {
+	// Primitives
+	case reflect.Bool, reflect.Chan, reflect.Func, reflect.Int, reflect.String, reflect.Invalid:
+		err = walkPrimitive(originalV, w)
+		return
+	case reflect.Map:
+		err = walkMap(v, w)
+		return
+	case reflect.Slice:
+		err = walkSlice(v, w)
+		return
+	case reflect.Struct:
+		err = walkStruct(v, w)
+		return
+	case reflect.Array:
+		err = walkArray(v, w)
+		return
+	default:
+		panic("unsupported type: " + k.String())
+	}
+}
+
+func walkMap(v reflect.Value, w interface{}) error {
+	ew, ewok := w.(EnterExitWalker)
+	if ewok {
+		ew.Enter(Map)
+	}
+
+	if mw, ok := w.(MapWalker); ok {
+		if err := mw.Map(v); err != nil {
+			return err
+		}
+	}
+
+	for _, k := range v.MapKeys() {
+		kv := v.MapIndex(k)
+
+		if mw, ok := w.(MapWalker); ok {
+			if err := mw.MapElem(v, k, kv); err != nil {
+				return err
+			}
+		}
+
+		ew, ok := w.(EnterExitWalker)
+		if ok {
+			ew.Enter(MapKey)
+		}
+
+		if err := walk(k, w); err != nil {
+			return err
+		}
+
+		if ok {
+			ew.Exit(MapKey)
+			ew.Enter(MapValue)
+		}
+
+		// get the map value again as it may have changed in the MapElem call
+		if err := walk(v.MapIndex(k), w); err != nil {
+			return err
+		}
+
+		if ok {
+			ew.Exit(MapValue)
+		}
+	}
+
+	if ewok {
+		ew.Exit(Map)
+	}
+
+	return nil
+}
+
+func walkPrimitive(v reflect.Value, w interface{}) error {
+	if pw, ok := w.(PrimitiveWalker); ok {
+		return pw.Primitive(v)
+	}
+
+	return nil
+}
+
+func walkSlice(v reflect.Value, w interface{}) (err error) {
+	ew, ok := w.(EnterExitWalker)
+	if ok {
+		ew.Enter(Slice)
+	}
+
+	if sw, ok := w.(SliceWalker); ok {
+		if err := sw.Slice(v); err != nil {
+			return err
+		}
+	}
+
+	for i := 0; i < v.Len(); i++ {
+		elem := v.Index(i)
+
+		if sw, ok := w.(SliceWalker); ok {
+			if err := sw.SliceElem(i, elem); err != nil {
+				return err
+			}
+		}
+
+		ew, ok := w.(EnterExitWalker)
+		if ok {
+			ew.Enter(SliceElem)
+		}
+
+		if err := walk(elem, w); err != nil {
+			return err
+		}
+
+		if ok {
+			ew.Exit(SliceElem)
+		}
+	}
+
+	ew, ok = w.(EnterExitWalker)
+	if ok {
+		ew.Exit(Slice)
+	}
+
+	return nil
+}
+
+func walkArray(v reflect.Value, w interface{}) (err error) {
+	ew, ok := w.(EnterExitWalker)
+	if ok {
+		ew.Enter(Array)
+	}
+
+	if aw, ok := w.(ArrayWalker); ok {
+		if err := aw.Array(v); err != nil {
+			return err
+		}
+	}
+
+	for i := 0; i < v.Len(); i++ {
+		elem := v.Index(i)
+
+		if aw, ok := w.(ArrayWalker); ok {
+			if err := aw.ArrayElem(i, elem); err != nil {
+				return err
+			}
+		}
+
+		ew, ok := w.(EnterExitWalker)
+		if ok {
+			ew.Enter(ArrayElem)
+		}
+
+		if err := walk(elem, w); err != nil {
+			return err
+		}
+
+		if ok {
+			ew.Exit(ArrayElem)
+		}
+	}
+
+	ew, ok = w.(EnterExitWalker)
+	if ok {
+		ew.Exit(Array)
+	}
+
+	return nil
+}
+
+func walkStruct(v reflect.Value, w interface{}) (err error) {
+	ew, ewok := w.(EnterExitWalker)
+	if ewok {
+		ew.Enter(Struct)
+	}
+
+	skip := false
+	if sw, ok := w.(StructWalker); ok {
+		err = sw.Struct(v)
+		if err == SkipEntry {
+			skip = true
+			err = nil
+		}
+		if err != nil {
+			return
+		}
+	}
+
+	if !skip {
+		vt := v.Type()
+		for i := 0; i < vt.NumField(); i++ {
+			sf := vt.Field(i)
+			f := v.FieldByIndex([]int{i})
+
+			if sw, ok := w.(StructWalker); ok {
+				err = sw.StructField(sf, f)
+
+				// SkipEntry just pretends this field doesn't even exist
+				if err == SkipEntry {
+					continue
+				}
+
+				if err != nil {
+					return
+				}
+			}
+
+			ew, ok := w.(EnterExitWalker)
+			if ok {
+				ew.Enter(StructField)
+			}
+
+			err = walk(f, w)
+			if err != nil {
+				return
+			}
+
+			if ok {
+				ew.Exit(StructField)
+			}
+		}
+	}
+
+	if ewok {
+		ew.Exit(Struct)
+	}
+
+	return nil
+}