mirror of
https://github.com/letic/terraform-provider-google.git
synced 2024-09-19 17:50:00 +00:00
278 lines
7.6 KiB
Go
278 lines
7.6 KiB
Go
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// Copyright 2017, The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE.md file.
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// Package value provides functionality for reflect.Value types.
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package value
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import (
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"fmt"
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"reflect"
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"strconv"
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"strings"
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"unicode"
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)
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var stringerIface = reflect.TypeOf((*fmt.Stringer)(nil)).Elem()
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// Format formats the value v as a string.
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//
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// This is similar to fmt.Sprintf("%+v", v) except this:
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// * Prints the type unless it can be elided
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// * Avoids printing struct fields that are zero
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// * Prints a nil-slice as being nil, not empty
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// * Prints map entries in deterministic order
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func Format(v reflect.Value, conf FormatConfig) string {
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conf.printType = true
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conf.followPointers = true
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conf.realPointers = true
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return formatAny(v, conf, nil)
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}
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type FormatConfig struct {
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UseStringer bool // Should the String method be used if available?
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printType bool // Should we print the type before the value?
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PrintPrimitiveType bool // Should we print the type of primitives?
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followPointers bool // Should we recursively follow pointers?
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realPointers bool // Should we print the real address of pointers?
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}
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func formatAny(v reflect.Value, conf FormatConfig, visited map[uintptr]bool) string {
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// TODO: Should this be a multi-line printout in certain situations?
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if !v.IsValid() {
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return "<non-existent>"
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}
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if conf.UseStringer && v.Type().Implements(stringerIface) && v.CanInterface() {
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if (v.Kind() == reflect.Ptr || v.Kind() == reflect.Interface) && v.IsNil() {
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return "<nil>"
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}
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const stringerPrefix = "s" // Indicates that the String method was used
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s := v.Interface().(fmt.Stringer).String()
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return stringerPrefix + formatString(s)
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}
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switch v.Kind() {
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case reflect.Bool:
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return formatPrimitive(v.Type(), v.Bool(), conf)
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case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
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return formatPrimitive(v.Type(), v.Int(), conf)
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case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
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if v.Type().PkgPath() == "" || v.Kind() == reflect.Uintptr {
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// Unnamed uints are usually bytes or words, so use hexadecimal.
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return formatPrimitive(v.Type(), formatHex(v.Uint()), conf)
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}
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return formatPrimitive(v.Type(), v.Uint(), conf)
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case reflect.Float32, reflect.Float64:
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return formatPrimitive(v.Type(), v.Float(), conf)
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case reflect.Complex64, reflect.Complex128:
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return formatPrimitive(v.Type(), v.Complex(), conf)
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case reflect.String:
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return formatPrimitive(v.Type(), formatString(v.String()), conf)
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case reflect.UnsafePointer, reflect.Chan, reflect.Func:
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return formatPointer(v, conf)
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case reflect.Ptr:
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if v.IsNil() {
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if conf.printType {
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return fmt.Sprintf("(%v)(nil)", v.Type())
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}
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return "<nil>"
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}
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if visited[v.Pointer()] || !conf.followPointers {
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return formatPointer(v, conf)
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}
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visited = insertPointer(visited, v.Pointer())
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return "&" + formatAny(v.Elem(), conf, visited)
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case reflect.Interface:
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if v.IsNil() {
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if conf.printType {
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return fmt.Sprintf("%v(nil)", v.Type())
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}
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return "<nil>"
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}
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return formatAny(v.Elem(), conf, visited)
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case reflect.Slice:
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if v.IsNil() {
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if conf.printType {
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return fmt.Sprintf("%v(nil)", v.Type())
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}
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return "<nil>"
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}
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if visited[v.Pointer()] {
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return formatPointer(v, conf)
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}
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visited = insertPointer(visited, v.Pointer())
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fallthrough
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case reflect.Array:
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var ss []string
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subConf := conf
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subConf.printType = v.Type().Elem().Kind() == reflect.Interface
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for i := 0; i < v.Len(); i++ {
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s := formatAny(v.Index(i), subConf, visited)
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ss = append(ss, s)
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}
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s := fmt.Sprintf("{%s}", strings.Join(ss, ", "))
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if conf.printType {
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return v.Type().String() + s
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}
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return s
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case reflect.Map:
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if v.IsNil() {
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if conf.printType {
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return fmt.Sprintf("%v(nil)", v.Type())
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}
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return "<nil>"
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}
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if visited[v.Pointer()] {
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return formatPointer(v, conf)
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}
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visited = insertPointer(visited, v.Pointer())
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var ss []string
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keyConf, valConf := conf, conf
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keyConf.printType = v.Type().Key().Kind() == reflect.Interface
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keyConf.followPointers = false
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valConf.printType = v.Type().Elem().Kind() == reflect.Interface
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for _, k := range SortKeys(v.MapKeys()) {
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sk := formatAny(k, keyConf, visited)
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sv := formatAny(v.MapIndex(k), valConf, visited)
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ss = append(ss, fmt.Sprintf("%s: %s", sk, sv))
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}
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s := fmt.Sprintf("{%s}", strings.Join(ss, ", "))
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if conf.printType {
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return v.Type().String() + s
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}
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return s
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case reflect.Struct:
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var ss []string
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subConf := conf
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subConf.printType = true
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for i := 0; i < v.NumField(); i++ {
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vv := v.Field(i)
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if isZero(vv) {
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continue // Elide zero value fields
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}
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name := v.Type().Field(i).Name
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subConf.UseStringer = conf.UseStringer
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s := formatAny(vv, subConf, visited)
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ss = append(ss, fmt.Sprintf("%s: %s", name, s))
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}
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s := fmt.Sprintf("{%s}", strings.Join(ss, ", "))
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if conf.printType {
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return v.Type().String() + s
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}
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return s
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default:
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panic(fmt.Sprintf("%v kind not handled", v.Kind()))
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}
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}
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func formatString(s string) string {
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// Use quoted string if it the same length as a raw string literal.
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// Otherwise, attempt to use the raw string form.
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qs := strconv.Quote(s)
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if len(qs) == 1+len(s)+1 {
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return qs
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}
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// Disallow newlines to ensure output is a single line.
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// Only allow printable runes for readability purposes.
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rawInvalid := func(r rune) bool {
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return r == '`' || r == '\n' || !unicode.IsPrint(r)
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}
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if strings.IndexFunc(s, rawInvalid) < 0 {
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return "`" + s + "`"
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}
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return qs
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}
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func formatPrimitive(t reflect.Type, v interface{}, conf FormatConfig) string {
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if conf.printType && (conf.PrintPrimitiveType || t.PkgPath() != "") {
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return fmt.Sprintf("%v(%v)", t, v)
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}
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return fmt.Sprintf("%v", v)
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}
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func formatPointer(v reflect.Value, conf FormatConfig) string {
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p := v.Pointer()
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if !conf.realPointers {
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p = 0 // For deterministic printing purposes
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}
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s := formatHex(uint64(p))
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if conf.printType {
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return fmt.Sprintf("(%v)(%s)", v.Type(), s)
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}
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return s
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}
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func formatHex(u uint64) string {
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var f string
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switch {
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case u <= 0xff:
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f = "0x%02x"
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case u <= 0xffff:
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f = "0x%04x"
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case u <= 0xffffff:
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f = "0x%06x"
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case u <= 0xffffffff:
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f = "0x%08x"
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case u <= 0xffffffffff:
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f = "0x%010x"
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case u <= 0xffffffffffff:
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f = "0x%012x"
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case u <= 0xffffffffffffff:
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f = "0x%014x"
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case u <= 0xffffffffffffffff:
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f = "0x%016x"
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}
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return fmt.Sprintf(f, u)
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}
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// insertPointer insert p into m, allocating m if necessary.
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func insertPointer(m map[uintptr]bool, p uintptr) map[uintptr]bool {
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if m == nil {
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m = make(map[uintptr]bool)
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}
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m[p] = true
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return m
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}
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// isZero reports whether v is the zero value.
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// This does not rely on Interface and so can be used on unexported fields.
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func isZero(v reflect.Value) bool {
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switch v.Kind() {
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case reflect.Bool:
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return v.Bool() == false
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case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
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return v.Int() == 0
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case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
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return v.Uint() == 0
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case reflect.Float32, reflect.Float64:
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return v.Float() == 0
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case reflect.Complex64, reflect.Complex128:
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return v.Complex() == 0
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case reflect.String:
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return v.String() == ""
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case reflect.UnsafePointer:
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return v.Pointer() == 0
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case reflect.Chan, reflect.Func, reflect.Interface, reflect.Ptr, reflect.Map, reflect.Slice:
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return v.IsNil()
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case reflect.Array:
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for i := 0; i < v.Len(); i++ {
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if !isZero(v.Index(i)) {
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return false
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}
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}
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return true
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case reflect.Struct:
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for i := 0; i < v.NumField(); i++ {
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if !isZero(v.Field(i)) {
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return false
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}
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}
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return true
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}
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return false
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}
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