gitroast/vendor/github.com/smartystreets/assertions/internal/go-render/render/render.go

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2016-11-03 22:16:01 +00:00
// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
package render
import (
"bytes"
"fmt"
"reflect"
"sort"
"strconv"
)
var builtinTypeMap = map[reflect.Kind]string{
reflect.Bool: "bool",
reflect.Complex128: "complex128",
reflect.Complex64: "complex64",
reflect.Float32: "float32",
reflect.Float64: "float64",
reflect.Int16: "int16",
reflect.Int32: "int32",
reflect.Int64: "int64",
reflect.Int8: "int8",
reflect.Int: "int",
reflect.String: "string",
reflect.Uint16: "uint16",
reflect.Uint32: "uint32",
reflect.Uint64: "uint64",
reflect.Uint8: "uint8",
reflect.Uint: "uint",
reflect.Uintptr: "uintptr",
}
var builtinTypeSet = map[string]struct{}{}
func init() {
for _, v := range builtinTypeMap {
builtinTypeSet[v] = struct{}{}
}
}
var typeOfString = reflect.TypeOf("")
var typeOfInt = reflect.TypeOf(int(1))
var typeOfUint = reflect.TypeOf(uint(1))
var typeOfFloat = reflect.TypeOf(10.1)
// Render converts a structure to a string representation. Unline the "%#v"
// format string, this resolves pointer types' contents in structs, maps, and
// slices/arrays and prints their field values.
func Render(v interface{}) string {
buf := bytes.Buffer{}
s := (*traverseState)(nil)
s.render(&buf, 0, reflect.ValueOf(v), false)
return buf.String()
}
// renderPointer is called to render a pointer value.
//
// This is overridable so that the test suite can have deterministic pointer
// values in its expectations.
var renderPointer = func(buf *bytes.Buffer, p uintptr) {
fmt.Fprintf(buf, "0x%016x", p)
}
// traverseState is used to note and avoid recursion as struct members are being
// traversed.
//
// traverseState is allowed to be nil. Specifically, the root state is nil.
type traverseState struct {
parent *traverseState
ptr uintptr
}
func (s *traverseState) forkFor(ptr uintptr) *traverseState {
for cur := s; cur != nil; cur = cur.parent {
if ptr == cur.ptr {
return nil
}
}
fs := &traverseState{
parent: s,
ptr: ptr,
}
return fs
}
func (s *traverseState) render(buf *bytes.Buffer, ptrs int, v reflect.Value, implicit bool) {
if v.Kind() == reflect.Invalid {
buf.WriteString("nil")
return
}
vt := v.Type()
// If the type being rendered is a potentially recursive type (a type that
// can contain itself as a member), we need to avoid recursion.
//
// If we've already seen this type before, mark that this is the case and
// write a recursion placeholder instead of actually rendering it.
//
// If we haven't seen it before, fork our `seen` tracking so any higher-up
// renderers will also render it at least once, then mark that we've seen it
// to avoid recursing on lower layers.
pe := uintptr(0)
vk := vt.Kind()
switch vk {
case reflect.Ptr:
// Since structs and arrays aren't pointers, they can't directly be
// recursed, but they can contain pointers to themselves. Record their
// pointer to avoid this.
switch v.Elem().Kind() {
case reflect.Struct, reflect.Array:
pe = v.Pointer()
}
case reflect.Slice, reflect.Map:
pe = v.Pointer()
}
if pe != 0 {
s = s.forkFor(pe)
if s == nil {
buf.WriteString("<REC(")
if !implicit {
writeType(buf, ptrs, vt)
}
buf.WriteString(")>")
return
}
}
isAnon := func(t reflect.Type) bool {
if t.Name() != "" {
if _, ok := builtinTypeSet[t.Name()]; !ok {
return false
}
}
return t.Kind() != reflect.Interface
}
switch vk {
case reflect.Struct:
if !implicit {
writeType(buf, ptrs, vt)
}
structAnon := vt.Name() == ""
buf.WriteRune('{')
for i := 0; i < vt.NumField(); i++ {
if i > 0 {
buf.WriteString(", ")
}
anon := structAnon && isAnon(vt.Field(i).Type)
if !anon {
buf.WriteString(vt.Field(i).Name)
buf.WriteRune(':')
}
s.render(buf, 0, v.Field(i), anon)
}
buf.WriteRune('}')
case reflect.Slice:
if v.IsNil() {
if !implicit {
writeType(buf, ptrs, vt)
buf.WriteString("(nil)")
} else {
buf.WriteString("nil")
}
return
}
fallthrough
case reflect.Array:
if !implicit {
writeType(buf, ptrs, vt)
}
anon := vt.Name() == "" && isAnon(vt.Elem())
buf.WriteString("{")
for i := 0; i < v.Len(); i++ {
if i > 0 {
buf.WriteString(", ")
}
s.render(buf, 0, v.Index(i), anon)
}
buf.WriteRune('}')
case reflect.Map:
if !implicit {
writeType(buf, ptrs, vt)
}
if v.IsNil() {
buf.WriteString("(nil)")
} else {
buf.WriteString("{")
mkeys := v.MapKeys()
tryAndSortMapKeys(vt, mkeys)
kt := vt.Key()
keyAnon := typeOfString.ConvertibleTo(kt) || typeOfInt.ConvertibleTo(kt) || typeOfUint.ConvertibleTo(kt) || typeOfFloat.ConvertibleTo(kt)
valAnon := vt.Name() == "" && isAnon(vt.Elem())
for i, mk := range mkeys {
if i > 0 {
buf.WriteString(", ")
}
s.render(buf, 0, mk, keyAnon)
buf.WriteString(":")
s.render(buf, 0, v.MapIndex(mk), valAnon)
}
buf.WriteRune('}')
}
case reflect.Ptr:
ptrs++
fallthrough
case reflect.Interface:
if v.IsNil() {
writeType(buf, ptrs, v.Type())
buf.WriteString("(nil)")
} else {
s.render(buf, ptrs, v.Elem(), false)
}
case reflect.Chan, reflect.Func, reflect.UnsafePointer:
writeType(buf, ptrs, vt)
buf.WriteRune('(')
renderPointer(buf, v.Pointer())
buf.WriteRune(')')
default:
tstr := vt.String()
implicit = implicit || (ptrs == 0 && builtinTypeMap[vk] == tstr)
if !implicit {
writeType(buf, ptrs, vt)
buf.WriteRune('(')
}
switch vk {
case reflect.String:
fmt.Fprintf(buf, "%q", v.String())
case reflect.Bool:
fmt.Fprintf(buf, "%v", v.Bool())
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
fmt.Fprintf(buf, "%d", v.Int())
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
fmt.Fprintf(buf, "%d", v.Uint())
case reflect.Float32, reflect.Float64:
fmt.Fprintf(buf, "%g", v.Float())
case reflect.Complex64, reflect.Complex128:
fmt.Fprintf(buf, "%g", v.Complex())
}
if !implicit {
buf.WriteRune(')')
}
}
}
func writeType(buf *bytes.Buffer, ptrs int, t reflect.Type) {
parens := ptrs > 0
switch t.Kind() {
case reflect.Chan, reflect.Func, reflect.UnsafePointer:
parens = true
}
if parens {
buf.WriteRune('(')
for i := 0; i < ptrs; i++ {
buf.WriteRune('*')
}
}
switch t.Kind() {
case reflect.Ptr:
if ptrs == 0 {
// This pointer was referenced from within writeType (e.g., as part of
// rendering a list), and so hasn't had its pointer asterisk accounted
// for.
buf.WriteRune('*')
}
writeType(buf, 0, t.Elem())
case reflect.Interface:
if n := t.Name(); n != "" {
buf.WriteString(t.String())
} else {
buf.WriteString("interface{}")
}
case reflect.Array:
buf.WriteRune('[')
buf.WriteString(strconv.FormatInt(int64(t.Len()), 10))
buf.WriteRune(']')
writeType(buf, 0, t.Elem())
case reflect.Slice:
if t == reflect.SliceOf(t.Elem()) {
buf.WriteString("[]")
writeType(buf, 0, t.Elem())
} else {
// Custom slice type, use type name.
buf.WriteString(t.String())
}
case reflect.Map:
if t == reflect.MapOf(t.Key(), t.Elem()) {
buf.WriteString("map[")
writeType(buf, 0, t.Key())
buf.WriteRune(']')
writeType(buf, 0, t.Elem())
} else {
// Custom map type, use type name.
buf.WriteString(t.String())
}
default:
buf.WriteString(t.String())
}
if parens {
buf.WriteRune(')')
}
}
type cmpFn func(a, b reflect.Value) int
type sortableValueSlice struct {
cmp cmpFn
elements []reflect.Value
}
func (s sortableValueSlice) Len() int {
return len(s.elements)
}
func (s sortableValueSlice) Less(i, j int) bool {
return s.cmp(s.elements[i], s.elements[j]) < 0
}
func (s sortableValueSlice) Swap(i, j int) {
s.elements[i], s.elements[j] = s.elements[j], s.elements[i]
}
// cmpForType returns a cmpFn which sorts the data for some type t in the same
// order that a go-native map key is compared for equality.
func cmpForType(t reflect.Type) cmpFn {
switch t.Kind() {
case reflect.String:
return func(av, bv reflect.Value) int {
a, b := av.String(), bv.String()
if a < b {
return -1
} else if a > b {
return 1
}
return 0
}
case reflect.Bool:
return func(av, bv reflect.Value) int {
a, b := av.Bool(), bv.Bool()
if !a && b {
return -1
} else if a && !b {
return 1
}
return 0
}
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
return func(av, bv reflect.Value) int {
a, b := av.Int(), bv.Int()
if a < b {
return -1
} else if a > b {
return 1
}
return 0
}
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32,
reflect.Uint64, reflect.Uintptr, reflect.UnsafePointer:
return func(av, bv reflect.Value) int {
a, b := av.Uint(), bv.Uint()
if a < b {
return -1
} else if a > b {
return 1
}
return 0
}
case reflect.Float32, reflect.Float64:
return func(av, bv reflect.Value) int {
a, b := av.Float(), bv.Float()
if a < b {
return -1
} else if a > b {
return 1
}
return 0
}
case reflect.Interface:
return func(av, bv reflect.Value) int {
a, b := av.InterfaceData(), bv.InterfaceData()
if a[0] < b[0] {
return -1
} else if a[0] > b[0] {
return 1
}
if a[1] < b[1] {
return -1
} else if a[1] > b[1] {
return 1
}
return 0
}
case reflect.Complex64, reflect.Complex128:
return func(av, bv reflect.Value) int {
a, b := av.Complex(), bv.Complex()
if real(a) < real(b) {
return -1
} else if real(a) > real(b) {
return 1
}
if imag(a) < imag(b) {
return -1
} else if imag(a) > imag(b) {
return 1
}
return 0
}
case reflect.Ptr, reflect.Chan:
return func(av, bv reflect.Value) int {
a, b := av.Pointer(), bv.Pointer()
if a < b {
return -1
} else if a > b {
return 1
}
return 0
}
case reflect.Struct:
cmpLst := make([]cmpFn, t.NumField())
for i := range cmpLst {
cmpLst[i] = cmpForType(t.Field(i).Type)
}
return func(a, b reflect.Value) int {
for i, cmp := range cmpLst {
if rslt := cmp(a.Field(i), b.Field(i)); rslt != 0 {
return rslt
}
}
return 0
}
}
return nil
}
func tryAndSortMapKeys(mt reflect.Type, k []reflect.Value) {
if cmp := cmpForType(mt.Key()); cmp != nil {
sort.Sort(sortableValueSlice{cmp, k})
}
}