bug command.

vendor/github.com/mitchellh/copystructure/copystructure.go

@@ -0,0 +1,548 @@
+package copystructure
+
+import (
+	"errors"
+	"reflect"
+	"sync"
+
+	"github.com/mitchellh/reflectwalk"
+)
+
+// Copy returns a deep copy of v.
+func Copy(v interface{}) (interface{}, error) {
+	return Config{}.Copy(v)
+}
+
+// CopierFunc is a function that knows how to deep copy a specific type.
+// Register these globally with the Copiers variable.
+type CopierFunc func(interface{}) (interface{}, error)
+
+// Copiers is a map of types that behave specially when they are copied.
+// If a type is found in this map while deep copying, this function
+// will be called to copy it instead of attempting to copy all fields.
+//
+// The key should be the type, obtained using: reflect.TypeOf(value with type).
+//
+// It is unsafe to write to this map after Copies have started. If you
+// are writing to this map while also copying, wrap all modifications to
+// this map as well as to Copy in a mutex.
+var Copiers map[reflect.Type]CopierFunc = make(map[reflect.Type]CopierFunc)
+
+// Must is a helper that wraps a call to a function returning
+// (interface{}, error) and panics if the error is non-nil. It is intended
+// for use in variable initializations and should only be used when a copy
+// error should be a crashing case.
+func Must(v interface{}, err error) interface{} {
+	if err != nil {
+		panic("copy error: " + err.Error())
+	}
+
+	return v
+}
+
+var errPointerRequired = errors.New("Copy argument must be a pointer when Lock is true")
+
+type Config struct {
+	// Lock any types that are a sync.Locker and are not a mutex while copying.
+	// If there is an RLocker method, use that to get the sync.Locker.
+	Lock bool
+
+	// Copiers is a map of types associated with a CopierFunc. Use the global
+	// Copiers map if this is nil.
+	Copiers map[reflect.Type]CopierFunc
+}
+
+func (c Config) Copy(v interface{}) (interface{}, error) {
+	if c.Lock && reflect.ValueOf(v).Kind() != reflect.Ptr {
+		return nil, errPointerRequired
+	}
+
+	w := new(walker)
+	if c.Lock {
+		w.useLocks = true
+	}
+
+	if c.Copiers == nil {
+		c.Copiers = Copiers
+	}
+
+	err := reflectwalk.Walk(v, w)
+	if err != nil {
+		return nil, err
+	}
+
+	// Get the result. If the result is nil, then we want to turn it
+	// into a typed nil if we can.
+	result := w.Result
+	if result == nil {
+		val := reflect.ValueOf(v)
+		result = reflect.Indirect(reflect.New(val.Type())).Interface()
+	}
+
+	return result, nil
+}
+
+// Return the key used to index interfaces types we've seen. Store the number
+// of pointers in the upper 32bits, and the depth in the lower 32bits. This is
+// easy to calculate, easy to match a key with our current depth, and we don't
+// need to deal with initializing and cleaning up nested maps or slices.
+func ifaceKey(pointers, depth int) uint64 {
+	return uint64(pointers)<<32 | uint64(depth)
+}
+
+type walker struct {
+	Result interface{}
+
+	depth       int
+	ignoreDepth int
+	vals        []reflect.Value
+	cs          []reflect.Value
+
+	// This stores the number of pointers we've walked over, indexed by depth.
+	ps []int
+
+	// If an interface is indirected by a pointer, we need to know the type of
+	// interface to create when creating the new value.  Store the interface
+	// types here, indexed by both the walk depth and the number of pointers
+	// already seen at that depth. Use ifaceKey to calculate the proper uint64
+	// value.
+	ifaceTypes map[uint64]reflect.Type
+
+	// any locks we've taken, indexed by depth
+	locks []sync.Locker
+	// take locks while walking the structure
+	useLocks bool
+}
+
+func (w *walker) Enter(l reflectwalk.Location) error {
+	w.depth++
+
+	// ensure we have enough elements to index via w.depth
+	for w.depth >= len(w.locks) {
+		w.locks = append(w.locks, nil)
+	}
+
+	for len(w.ps) < w.depth+1 {
+		w.ps = append(w.ps, 0)
+	}
+
+	return nil
+}
+
+func (w *walker) Exit(l reflectwalk.Location) error {
+	locker := w.locks[w.depth]
+	w.locks[w.depth] = nil
+	if locker != nil {
+		defer locker.Unlock()
+	}
+
+	// clear out pointers and interfaces as we exit the stack
+	w.ps[w.depth] = 0
+
+	for k := range w.ifaceTypes {
+		mask := uint64(^uint32(0))
+		if k&mask == uint64(w.depth) {
+			delete(w.ifaceTypes, k)
+		}
+	}
+
+	w.depth--
+	if w.ignoreDepth > w.depth {
+		w.ignoreDepth = 0
+	}
+
+	if w.ignoring() {
+		return nil
+	}
+
+	switch l {
+	case reflectwalk.Array:
+		fallthrough
+	case reflectwalk.Map:
+		fallthrough
+	case reflectwalk.Slice:
+		w.replacePointerMaybe()
+
+		// Pop map off our container
+		w.cs = w.cs[:len(w.cs)-1]
+	case reflectwalk.MapValue:
+		// Pop off the key and value
+		mv := w.valPop()
+		mk := w.valPop()
+		m := w.cs[len(w.cs)-1]
+
+		// If mv is the zero value, SetMapIndex deletes the key form the map,
+		// or in this case never adds it. We need to create a properly typed
+		// zero value so that this key can be set.
+		if !mv.IsValid() {
+			mv = reflect.Zero(m.Elem().Type().Elem())
+		}
+		m.Elem().SetMapIndex(mk, mv)
+	case reflectwalk.ArrayElem:
+		// Pop off the value and the index and set it on the array
+		v := w.valPop()
+		i := w.valPop().Interface().(int)
+		if v.IsValid() {
+			a := w.cs[len(w.cs)-1]
+			ae := a.Elem().Index(i) // storing array as pointer on stack - so need Elem() call
+			if ae.CanSet() {
+				ae.Set(v)
+			}
+		}
+	case reflectwalk.SliceElem:
+		// Pop off the value and the index and set it on the slice
+		v := w.valPop()
+		i := w.valPop().Interface().(int)
+		if v.IsValid() {
+			s := w.cs[len(w.cs)-1]
+			se := s.Elem().Index(i)
+			if se.CanSet() {
+				se.Set(v)
+			}
+		}
+	case reflectwalk.Struct:
+		w.replacePointerMaybe()
+
+		// Remove the struct from the container stack
+		w.cs = w.cs[:len(w.cs)-1]
+	case reflectwalk.StructField:
+		// Pop off the value and the field
+		v := w.valPop()
+		f := w.valPop().Interface().(reflect.StructField)
+		if v.IsValid() {
+			s := w.cs[len(w.cs)-1]
+			sf := reflect.Indirect(s).FieldByName(f.Name)
+
+			if sf.CanSet() {
+				sf.Set(v)
+			}
+		}
+	case reflectwalk.WalkLoc:
+		// Clear out the slices for GC
+		w.cs = nil
+		w.vals = nil
+	}
+
+	return nil
+}
+
+func (w *walker) Map(m reflect.Value) error {
+	if w.ignoring() {
+		return nil
+	}
+	w.lock(m)
+
+	// Create the map. If the map itself is nil, then just make a nil map
+	var newMap reflect.Value
+	if m.IsNil() {
+		newMap = reflect.New(m.Type())
+	} else {
+		newMap = wrapPtr(reflect.MakeMap(m.Type()))
+	}
+
+	w.cs = append(w.cs, newMap)
+	w.valPush(newMap)
+	return nil
+}
+
+func (w *walker) MapElem(m, k, v reflect.Value) error {
+	return nil
+}
+
+func (w *walker) PointerEnter(v bool) error {
+	if v {
+		w.ps[w.depth]++
+	}
+	return nil
+}
+
+func (w *walker) PointerExit(v bool) error {
+	if v {
+		w.ps[w.depth]--
+	}
+	return nil
+}
+
+func (w *walker) Interface(v reflect.Value) error {
+	if !v.IsValid() {
+		return nil
+	}
+	if w.ifaceTypes == nil {
+		w.ifaceTypes = make(map[uint64]reflect.Type)
+	}
+
+	w.ifaceTypes[ifaceKey(w.ps[w.depth], w.depth)] = v.Type()
+	return nil
+}
+
+func (w *walker) Primitive(v reflect.Value) error {
+	if w.ignoring() {
+		return nil
+	}
+	w.lock(v)
+
+	// IsValid verifies the v is non-zero and CanInterface verifies
+	// that we're allowed to read this value (unexported fields).
+	var newV reflect.Value
+	if v.IsValid() && v.CanInterface() {
+		newV = reflect.New(v.Type())
+		newV.Elem().Set(v)
+	}
+
+	w.valPush(newV)
+	w.replacePointerMaybe()
+	return nil
+}
+
+func (w *walker) Slice(s reflect.Value) error {
+	if w.ignoring() {
+		return nil
+	}
+	w.lock(s)
+
+	var newS reflect.Value
+	if s.IsNil() {
+		newS = reflect.New(s.Type())
+	} else {
+		newS = wrapPtr(reflect.MakeSlice(s.Type(), s.Len(), s.Cap()))
+	}
+
+	w.cs = append(w.cs, newS)
+	w.valPush(newS)
+	return nil
+}
+
+func (w *walker) SliceElem(i int, elem reflect.Value) error {
+	if w.ignoring() {
+		return nil
+	}
+
+	// We don't write the slice here because elem might still be
+	// arbitrarily complex. Just record the index and continue on.
+	w.valPush(reflect.ValueOf(i))
+
+	return nil
+}
+
+func (w *walker) Array(a reflect.Value) error {
+	if w.ignoring() {
+		return nil
+	}
+	w.lock(a)
+
+	newA := reflect.New(a.Type())
+
+	w.cs = append(w.cs, newA)
+	w.valPush(newA)
+	return nil
+}
+
+func (w *walker) ArrayElem(i int, elem reflect.Value) error {
+	if w.ignoring() {
+		return nil
+	}
+
+	// We don't write the array here because elem might still be
+	// arbitrarily complex. Just record the index and continue on.
+	w.valPush(reflect.ValueOf(i))
+
+	return nil
+}
+
+func (w *walker) Struct(s reflect.Value) error {
+	if w.ignoring() {
+		return nil
+	}
+	w.lock(s)
+
+	var v reflect.Value
+	if c, ok := Copiers[s.Type()]; ok {
+		// We have a Copier for this struct, so we use that copier to
+		// get the copy, and we ignore anything deeper than this.
+		w.ignoreDepth = w.depth
+
+		dup, err := c(s.Interface())
+		if err != nil {
+			return err
+		}
+
+		// We need to put a pointer to the value on the value stack,
+		// so allocate a new pointer and set it.
+		v = reflect.New(s.Type())
+		reflect.Indirect(v).Set(reflect.ValueOf(dup))
+	} else {
+		// No copier, we copy ourselves and allow reflectwalk to guide
+		// us deeper into the structure for copying.
+		v = reflect.New(s.Type())
+	}
+
+	// Push the value onto the value stack for setting the struct field,
+	// and add the struct itself to the containers stack in case we walk
+	// deeper so that its own fields can be modified.
+	w.valPush(v)
+	w.cs = append(w.cs, v)
+
+	return nil
+}
+
+func (w *walker) StructField(f reflect.StructField, v reflect.Value) error {
+	if w.ignoring() {
+		return nil
+	}
+
+	// If PkgPath is non-empty, this is a private (unexported) field.
+	// We do not set this unexported since the Go runtime doesn't allow us.
+	if f.PkgPath != "" {
+		return reflectwalk.SkipEntry
+	}
+
+	// Push the field onto the stack, we'll handle it when we exit
+	// the struct field in Exit...
+	w.valPush(reflect.ValueOf(f))
+	return nil
+}
+
+// ignore causes the walker to ignore any more values until we exit this on
+func (w *walker) ignore() {
+	w.ignoreDepth = w.depth
+}
+
+func (w *walker) ignoring() bool {
+	return w.ignoreDepth > 0 && w.depth >= w.ignoreDepth
+}
+
+func (w *walker) pointerPeek() bool {
+	return w.ps[w.depth] > 0
+}
+
+func (w *walker) valPop() reflect.Value {
+	result := w.vals[len(w.vals)-1]
+	w.vals = w.vals[:len(w.vals)-1]
+
+	// If we're out of values, that means we popped everything off. In
+	// this case, we reset the result so the next pushed value becomes
+	// the result.
+	if len(w.vals) == 0 {
+		w.Result = nil
+	}
+
+	return result
+}
+
+func (w *walker) valPush(v reflect.Value) {
+	w.vals = append(w.vals, v)
+
+	// If we haven't set the result yet, then this is the result since
+	// it is the first (outermost) value we're seeing.
+	if w.Result == nil && v.IsValid() {
+		w.Result = v.Interface()
+	}
+}
+
+func (w *walker) replacePointerMaybe() {
+	// Determine the last pointer value. If it is NOT a pointer, then
+	// we need to push that onto the stack.
+	if !w.pointerPeek() {
+		w.valPush(reflect.Indirect(w.valPop()))
+		return
+	}
+
+	v := w.valPop()
+
+	// If the expected type is a pointer to an interface of any depth,
+	// such as *interface{}, **interface{}, etc., then we need to convert
+	// the value "v" from *CONCRETE to *interface{} so types match for
+	// Set.
+	//
+	// Example if v is type *Foo where Foo is a struct, v would become
+	// *interface{} instead. This only happens if we have an interface expectation
+	// at this depth.
+	//
+	// For more info, see GH-16
+	if iType, ok := w.ifaceTypes[ifaceKey(w.ps[w.depth], w.depth)]; ok && iType.Kind() == reflect.Interface {
+		y := reflect.New(iType)           // Create *interface{}
+		y.Elem().Set(reflect.Indirect(v)) // Assign "Foo" to interface{} (dereferenced)
+		v = y                             // v is now typed *interface{} (where *v = Foo)
+	}
+
+	for i := 1; i < w.ps[w.depth]; i++ {
+		if iType, ok := w.ifaceTypes[ifaceKey(w.ps[w.depth]-i, w.depth)]; ok {
+			iface := reflect.New(iType).Elem()
+			iface.Set(v)
+			v = iface
+		}
+
+		p := reflect.New(v.Type())
+		p.Elem().Set(v)
+		v = p
+	}
+
+	w.valPush(v)
+}
+
+// if this value is a Locker, lock it and add it to the locks slice
+func (w *walker) lock(v reflect.Value) {
+	if !w.useLocks {
+		return
+	}
+
+	if !v.IsValid() || !v.CanInterface() {
+		return
+	}
+
+	type rlocker interface {
+		RLocker() sync.Locker
+	}
+
+	var locker sync.Locker
+
+	// We can't call Interface() on a value directly, since that requires
+	// a copy. This is OK, since the pointer to a value which is a sync.Locker
+	// is also a sync.Locker.
+	if v.Kind() == reflect.Ptr {
+		switch l := v.Interface().(type) {
+		case rlocker:
+			// don't lock a mutex directly
+			if _, ok := l.(*sync.RWMutex); !ok {
+				locker = l.RLocker()
+			}
+		case sync.Locker:
+			locker = l
+		}
+	} else if v.CanAddr() {
+		switch l := v.Addr().Interface().(type) {
+		case rlocker:
+			// don't lock a mutex directly
+			if _, ok := l.(*sync.RWMutex); !ok {
+				locker = l.RLocker()
+			}
+		case sync.Locker:
+			locker = l
+		}
+	}
+
+	// still no callable locker
+	if locker == nil {
+		return
+	}
+
+	// don't lock a mutex directly
+	switch locker.(type) {
+	case *sync.Mutex, *sync.RWMutex:
+		return
+	}
+
+	locker.Lock()
+	w.locks[w.depth] = locker
+}
+
+// wrapPtr is a helper that takes v and always make it *v. copystructure
+// stores things internally as pointers until the last moment before unwrapping
+func wrapPtr(v reflect.Value) reflect.Value {
+	if !v.IsValid() {
+		return v
+	}
+	vPtr := reflect.New(v.Type())
+	vPtr.Elem().Set(v)
+	return vPtr
+}