1 files changed, 97 insertions, 90 deletions

diff --git a/vendor/github.com/davecgh/go-spew/spew/bypass.go b/vendor/github.com/davecgh/go-spew/spew/bypass.go
index 792994785..8a4a6589a 100644
--- a/vendor/github.com/davecgh/go-spew/spew/bypass.go
+++ b/vendor/github.com/davecgh/go-spew/spew/bypass.go
@@ -16,9 +16,7 @@
 // when the code is not running on Google App Engine, compiled by GopherJS, and
 // "-tags safe" is not added to the go build command line.  The "disableunsafe"
 // tag is deprecated and thus should not be used.
-// Go versions prior to 1.4 are disabled because they use a different layout
-// for interfaces which make the implementation of unsafeReflectValue more complex.
-// +build !js,!appengine,!safe,!disableunsafe,go1.4
+// +build !js,!appengine,!safe,!disableunsafe
 
 package spew
 
@@ -36,49 +34,80 @@ const (
 	ptrSize = unsafe.Sizeof((*byte)(nil))
 )
 
-type flag uintptr
-
 var (
-	// flagRO indicates whether the value field of a reflect.Value
-	// is read-only.
-	flagRO flag
-
-	// flagAddr indicates whether the address of the reflect.Value's
-	// value may be taken.
-	flagAddr flag
+	// offsetPtr, offsetScalar, and offsetFlag are the offsets for the
+	// internal reflect.Value fields.  These values are valid before golang
+	// commit ecccf07e7f9d which changed the format.  The are also valid
+	// after commit 82f48826c6c7 which changed the format again to mirror
+	// the original format.  Code in the init function updates these offsets
+	// as necessary.
+	offsetPtr    = uintptr(ptrSize)
+	offsetScalar = uintptr(0)
+	offsetFlag   = uintptr(ptrSize * 2)
+
+	// flagKindWidth and flagKindShift indicate various bits that the
+	// reflect package uses internally to track kind information.
+	//
+	// flagRO indicates whether or not the value field of a reflect.Value is
+	// read-only.
+	//
+	// flagIndir indicates whether the value field of a reflect.Value is
+	// the actual data or a pointer to the data.
+	//
+	// These values are valid before golang commit 90a7c3c86944 which
+	// changed their positions.  Code in the init function updates these
+	// flags as necessary.
+	flagKindWidth = uintptr(5)
+	flagKindShift = uintptr(flagKindWidth - 1)
+	flagRO        = uintptr(1 << 0)
+	flagIndir     = uintptr(1 << 1)
 )
 
-// flagKindMask holds the bits that make up the kind
-// part of the flags field. In all the supported versions,
-// it is in the lower 5 bits.
-const flagKindMask = flag(0x1f)
-
-// Different versions of Go have used different
-// bit layouts for the flags type. This table
-// records the known combinations.
-var okFlags = []struct {
-	ro, addr flag
-}{{
-	// From Go 1.4 to 1.5
-	ro:   1 << 5,
-	addr: 1 << 7,
-}, {
-	// Up to Go tip.
-	ro:   1<<5 | 1<<6,
-	addr: 1 << 8,
-}}
-
-var flagValOffset = func() uintptr {
-	field, ok := reflect.TypeOf(reflect.Value{}).FieldByName("flag")
-	if !ok {
-		panic("reflect.Value has no flag field")
+func init() {
+	// Older versions of reflect.Value stored small integers directly in the
+	// ptr field (which is named val in the older versions).  Versions
+	// between commits ecccf07e7f9d and 82f48826c6c7 added a new field named
+	// scalar for this purpose which unfortunately came before the flag
+	// field, so the offset of the flag field is different for those
+	// versions.
+	//
+	// This code constructs a new reflect.Value from a known small integer
+	// and checks if the size of the reflect.Value struct indicates it has
+	// the scalar field. When it does, the offsets are updated accordingly.
+	vv := reflect.ValueOf(0xf00)
+	if unsafe.Sizeof(vv) == (ptrSize * 4) {
+		offsetScalar = ptrSize * 2
+		offsetFlag = ptrSize * 3
 	}
-	return field.Offset
-}()
 
-// flagField returns a pointer to the flag field of a reflect.Value.
-func flagField(v *reflect.Value) *flag {
-	return (*flag)(unsafe.Pointer(uintptr(unsafe.Pointer(v)) + flagValOffset))
+	// Commit 90a7c3c86944 changed the flag positions such that the low
+	// order bits are the kind.  This code extracts the kind from the flags
+	// field and ensures it's the correct type.  When it's not, the flag
+	// order has been changed to the newer format, so the flags are updated
+	// accordingly.
+	upf := unsafe.Pointer(uintptr(unsafe.Pointer(&vv)) + offsetFlag)
+	upfv := *(*uintptr)(upf)
+	flagKindMask := uintptr((1<<flagKindWidth - 1) << flagKindShift)
+	if (upfv&flagKindMask)>>flagKindShift != uintptr(reflect.Int) {
+		flagKindShift = 0
+		flagRO = 1 << 5
+		flagIndir = 1 << 6
+
+		// Commit adf9b30e5594 modified the flags to separate the
+		// flagRO flag into two bits which specifies whether or not the
+		// field is embedded.  This causes flagIndir to move over a bit
+		// and means that flagRO is the combination of either of the
+		// original flagRO bit and the new bit.
+		//
+		// This code detects the change by extracting what used to be
+		// the indirect bit to ensure it's set.  When it's not, the flag
+		// order has been changed to the newer format, so the flags are
+		// updated accordingly.
+		if upfv&flagIndir == 0 {
+			flagRO = 3 << 5
+			flagIndir = 1 << 7
+		}
+	}
 }
 
 // unsafeReflectValue converts the passed reflect.Value into a one that bypasses
@@ -90,56 +119,34 @@ func flagField(v *reflect.Value) *flag {
 // This allows us to check for implementations of the Stringer and error
 // interfaces to be used for pretty printing ordinarily unaddressable and
 // inaccessible values such as unexported struct fields.
-func unsafeReflectValue(v reflect.Value) reflect.Value {
-	if !v.IsValid() || (v.CanInterface() && v.CanAddr()) {
-		return v
-	}
-	flagFieldPtr := flagField(&v)
-	*flagFieldPtr &^= flagRO
-	*flagFieldPtr |= flagAddr
-	return v
-}
-
-// Sanity checks against future reflect package changes
-// to the type or semantics of the Value.flag field.
-func init() {
-	field, ok := reflect.TypeOf(reflect.Value{}).FieldByName("flag")
-	if !ok {
-		panic("reflect.Value has no flag field")
-	}
-	if field.Type.Kind() != reflect.TypeOf(flag(0)).Kind() {
-		panic("reflect.Value flag field has changed kind")
-	}
-	type t0 int
-	var t struct {
-		A t0
-		// t0 will have flagEmbedRO set.
-		t0
-		// a will have flagStickyRO set
-		a t0
+func unsafeReflectValue(v reflect.Value) (rv reflect.Value) {
+	indirects := 1
+	vt := v.Type()
+	upv := unsafe.Pointer(uintptr(unsafe.Pointer(&v)) + offsetPtr)
+	rvf := *(*uintptr)(unsafe.Pointer(uintptr(unsafe.Pointer(&v)) + offsetFlag))
+	if rvf&flagIndir != 0 {
+		vt = reflect.PtrTo(v.Type())
+		indirects++
+	} else if offsetScalar != 0 {
+		// The value is in the scalar field when it's not one of the
+		// reference types.
+		switch vt.Kind() {
+		case reflect.Uintptr:
+		case reflect.Chan:
+		case reflect.Func:
+		case reflect.Map:
+		case reflect.Ptr:
+		case reflect.UnsafePointer:
+		default:
+			upv = unsafe.Pointer(uintptr(unsafe.Pointer(&v)) +
+				offsetScalar)
+		}
 	}
-	vA := reflect.ValueOf(t).FieldByName("A")
-	va := reflect.ValueOf(t).FieldByName("a")
-	vt0 := reflect.ValueOf(t).FieldByName("t0")
-
-	// Infer flagRO from the difference between the flags
-	// for the (otherwise identical) fields in t.
-	flagPublic := *flagField(&vA)
-	flagWithRO := *flagField(&va) | *flagField(&vt0)
-	flagRO = flagPublic ^ flagWithRO
 
-	// Infer flagAddr from the difference between a value
-	// taken from a pointer and not.
-	vPtrA := reflect.ValueOf(&t).Elem().FieldByName("A")
-	flagNoPtr := *flagField(&vA)
-	flagPtr := *flagField(&vPtrA)
-	flagAddr = flagNoPtr ^ flagPtr
-
-	// Check that the inferred flags tally with one of the known versions.
-	for _, f := range okFlags {
-		if flagRO == f.ro && flagAddr == f.addr {
-			return
-		}
+	pv := reflect.NewAt(vt, upv)
+	rv = pv
+	for i := 0; i < indirects; i++ {
+		rv = rv.Elem()
 	}
-	panic("reflect.Value read-only flag has changed semantics")
+	return rv
 }