403 lines
13 KiB
Go
403 lines
13 KiB
Go
// Copyright 2019, 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 file.
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package cmp
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import (
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"bytes"
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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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"unicode/utf8"
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"github.com/google/go-cmp/cmp/internal/value"
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)
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type formatValueOptions struct {
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// AvoidStringer controls whether to avoid calling custom stringer
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// methods like error.Error or fmt.Stringer.String.
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AvoidStringer bool
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// PrintAddresses controls whether to print the address of all pointers,
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// slice elements, and maps.
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PrintAddresses bool
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// QualifiedNames controls whether FormatType uses the fully qualified name
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// (including the full package path as opposed to just the package name).
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QualifiedNames bool
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// VerbosityLevel controls the amount of output to produce.
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// A higher value produces more output. A value of zero or lower produces
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// no output (represented using an ellipsis).
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// If LimitVerbosity is false, then the level is treated as infinite.
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VerbosityLevel int
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// LimitVerbosity specifies that formatting should respect VerbosityLevel.
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LimitVerbosity bool
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}
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// FormatType prints the type as if it were wrapping s.
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// This may return s as-is depending on the current type and TypeMode mode.
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func (opts formatOptions) FormatType(t reflect.Type, s textNode) textNode {
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// Check whether to emit the type or not.
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switch opts.TypeMode {
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case autoType:
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switch t.Kind() {
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case reflect.Struct, reflect.Slice, reflect.Array, reflect.Map:
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if s.Equal(textNil) {
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return s
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}
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default:
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return s
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}
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if opts.DiffMode == diffIdentical {
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return s // elide type for identical nodes
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}
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case elideType:
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return s
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}
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// Determine the type label, applying special handling for unnamed types.
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typeName := value.TypeString(t, opts.QualifiedNames)
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if t.Name() == "" {
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// According to Go grammar, certain type literals contain symbols that
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// do not strongly bind to the next lexicographical token (e.g., *T).
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switch t.Kind() {
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case reflect.Chan, reflect.Func, reflect.Ptr:
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typeName = "(" + typeName + ")"
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}
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}
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return &textWrap{Prefix: typeName, Value: wrapParens(s)}
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}
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// wrapParens wraps s with a set of parenthesis, but avoids it if the
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// wrapped node itself is already surrounded by a pair of parenthesis or braces.
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// It handles unwrapping one level of pointer-reference nodes.
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func wrapParens(s textNode) textNode {
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var refNode *textWrap
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if s2, ok := s.(*textWrap); ok {
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// Unwrap a single pointer reference node.
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switch s2.Metadata.(type) {
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case leafReference, trunkReference, trunkReferences:
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refNode = s2
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if s3, ok := refNode.Value.(*textWrap); ok {
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s2 = s3
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}
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}
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// Already has delimiters that make parenthesis unnecessary.
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hasParens := strings.HasPrefix(s2.Prefix, "(") && strings.HasSuffix(s2.Suffix, ")")
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hasBraces := strings.HasPrefix(s2.Prefix, "{") && strings.HasSuffix(s2.Suffix, "}")
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if hasParens || hasBraces {
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return s
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}
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}
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if refNode != nil {
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refNode.Value = &textWrap{Prefix: "(", Value: refNode.Value, Suffix: ")"}
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return s
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}
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return &textWrap{Prefix: "(", Value: s, Suffix: ")"}
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}
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// FormatValue prints the reflect.Value, taking extra care to avoid descending
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// into pointers already in ptrs. As pointers are visited, ptrs is also updated.
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func (opts formatOptions) FormatValue(v reflect.Value, parentKind reflect.Kind, ptrs *pointerReferences) (out textNode) {
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if !v.IsValid() {
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return nil
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}
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t := v.Type()
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// Check slice element for cycles.
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if parentKind == reflect.Slice {
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ptrRef, visited := ptrs.Push(v.Addr())
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if visited {
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return makeLeafReference(ptrRef, false)
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}
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defer ptrs.Pop()
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defer func() { out = wrapTrunkReference(ptrRef, false, out) }()
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}
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// Check whether there is an Error or String method to call.
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if !opts.AvoidStringer && v.CanInterface() {
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// Avoid calling Error or String methods on nil receivers since many
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// implementations crash when doing so.
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if (t.Kind() != reflect.Ptr && t.Kind() != reflect.Interface) || !v.IsNil() {
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var prefix, strVal string
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func() {
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// Swallow and ignore any panics from String or Error.
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defer func() { recover() }()
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switch v := v.Interface().(type) {
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case error:
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strVal = v.Error()
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prefix = "e"
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case fmt.Stringer:
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strVal = v.String()
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prefix = "s"
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}
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}()
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if prefix != "" {
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return opts.formatString(prefix, strVal)
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}
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}
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}
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// Check whether to explicitly wrap the result with the type.
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var skipType bool
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defer func() {
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if !skipType {
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out = opts.FormatType(t, out)
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}
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}()
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switch t.Kind() {
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case reflect.Bool:
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return textLine(fmt.Sprint(v.Bool()))
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case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
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return textLine(fmt.Sprint(v.Int()))
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case reflect.Uint, reflect.Uint16, reflect.Uint32, reflect.Uint64:
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return textLine(fmt.Sprint(v.Uint()))
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case reflect.Uint8:
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if parentKind == reflect.Slice || parentKind == reflect.Array {
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return textLine(formatHex(v.Uint()))
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}
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return textLine(fmt.Sprint(v.Uint()))
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case reflect.Uintptr:
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return textLine(formatHex(v.Uint()))
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case reflect.Float32, reflect.Float64:
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return textLine(fmt.Sprint(v.Float()))
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case reflect.Complex64, reflect.Complex128:
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return textLine(fmt.Sprint(v.Complex()))
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case reflect.String:
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return opts.formatString("", v.String())
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case reflect.UnsafePointer, reflect.Chan, reflect.Func:
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return textLine(formatPointer(value.PointerOf(v), true))
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case reflect.Struct:
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var list textList
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v := makeAddressable(v) // needed for retrieveUnexportedField
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maxLen := v.NumField()
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if opts.LimitVerbosity {
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maxLen = ((1 << opts.verbosity()) >> 1) << 2 // 0, 4, 8, 16, 32, etc...
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opts.VerbosityLevel--
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}
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for i := 0; i < v.NumField(); i++ {
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vv := v.Field(i)
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if value.IsZero(vv) {
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continue // Elide fields with zero values
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}
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if len(list) == maxLen {
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list.AppendEllipsis(diffStats{})
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break
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}
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sf := t.Field(i)
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if supportExporters && !isExported(sf.Name) {
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vv = retrieveUnexportedField(v, sf, true)
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}
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s := opts.WithTypeMode(autoType).FormatValue(vv, t.Kind(), ptrs)
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list = append(list, textRecord{Key: sf.Name, Value: s})
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}
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return &textWrap{Prefix: "{", Value: list, Suffix: "}"}
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case reflect.Slice:
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if v.IsNil() {
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return textNil
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}
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// Check whether this is a []byte of text data.
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if t.Elem() == reflect.TypeOf(byte(0)) {
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b := v.Bytes()
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isPrintSpace := func(r rune) bool { return unicode.IsPrint(r) && unicode.IsSpace(r) }
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if len(b) > 0 && utf8.Valid(b) && len(bytes.TrimFunc(b, isPrintSpace)) == 0 {
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out = opts.formatString("", string(b))
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return opts.WithTypeMode(emitType).FormatType(t, out)
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}
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}
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fallthrough
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case reflect.Array:
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maxLen := v.Len()
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if opts.LimitVerbosity {
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maxLen = ((1 << opts.verbosity()) >> 1) << 2 // 0, 4, 8, 16, 32, etc...
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opts.VerbosityLevel--
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}
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var list textList
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for i := 0; i < v.Len(); i++ {
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if len(list) == maxLen {
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list.AppendEllipsis(diffStats{})
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break
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}
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s := opts.WithTypeMode(elideType).FormatValue(v.Index(i), t.Kind(), ptrs)
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list = append(list, textRecord{Value: s})
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}
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out = &textWrap{Prefix: "{", Value: list, Suffix: "}"}
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if t.Kind() == reflect.Slice && opts.PrintAddresses {
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header := fmt.Sprintf("ptr:%v, len:%d, cap:%d", formatPointer(value.PointerOf(v), false), v.Len(), v.Cap())
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out = &textWrap{Prefix: pointerDelimPrefix + header + pointerDelimSuffix, Value: out}
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}
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return out
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case reflect.Map:
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if v.IsNil() {
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return textNil
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}
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// Check pointer for cycles.
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ptrRef, visited := ptrs.Push(v)
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if visited {
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return makeLeafReference(ptrRef, opts.PrintAddresses)
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}
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defer ptrs.Pop()
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maxLen := v.Len()
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if opts.LimitVerbosity {
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maxLen = ((1 << opts.verbosity()) >> 1) << 2 // 0, 4, 8, 16, 32, etc...
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opts.VerbosityLevel--
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}
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var list textList
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for _, k := range value.SortKeys(v.MapKeys()) {
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if len(list) == maxLen {
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list.AppendEllipsis(diffStats{})
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break
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}
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sk := formatMapKey(k, false, ptrs)
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sv := opts.WithTypeMode(elideType).FormatValue(v.MapIndex(k), t.Kind(), ptrs)
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list = append(list, textRecord{Key: sk, Value: sv})
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}
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out = &textWrap{Prefix: "{", Value: list, Suffix: "}"}
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out = wrapTrunkReference(ptrRef, opts.PrintAddresses, out)
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return out
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case reflect.Ptr:
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if v.IsNil() {
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return textNil
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}
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// Check pointer for cycles.
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ptrRef, visited := ptrs.Push(v)
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if visited {
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out = makeLeafReference(ptrRef, opts.PrintAddresses)
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return &textWrap{Prefix: "&", Value: out}
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}
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defer ptrs.Pop()
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skipType = true // Let the underlying value print the type instead
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out = opts.FormatValue(v.Elem(), t.Kind(), ptrs)
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out = wrapTrunkReference(ptrRef, opts.PrintAddresses, out)
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out = &textWrap{Prefix: "&", Value: out}
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return out
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case reflect.Interface:
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if v.IsNil() {
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return textNil
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}
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// Interfaces accept different concrete types,
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// so configure the underlying value to explicitly print the type.
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skipType = true // Print the concrete type instead
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return opts.WithTypeMode(emitType).FormatValue(v.Elem(), t.Kind(), ptrs)
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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 (opts formatOptions) formatString(prefix, s string) textNode {
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maxLen := len(s)
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maxLines := strings.Count(s, "\n") + 1
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if opts.LimitVerbosity {
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maxLen = (1 << opts.verbosity()) << 5 // 32, 64, 128, 256, etc...
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maxLines = (1 << opts.verbosity()) << 2 // 4, 8, 16, 32, 64, etc...
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}
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// For multiline strings, use the triple-quote syntax,
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// but only use it when printing removed or inserted nodes since
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// we only want the extra verbosity for those cases.
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lines := strings.Split(strings.TrimSuffix(s, "\n"), "\n")
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isTripleQuoted := len(lines) >= 4 && (opts.DiffMode == '-' || opts.DiffMode == '+')
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for i := 0; i < len(lines) && isTripleQuoted; i++ {
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lines[i] = strings.TrimPrefix(strings.TrimSuffix(lines[i], "\r"), "\r") // trim leading/trailing carriage returns for legacy Windows endline support
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isPrintable := func(r rune) bool {
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return unicode.IsPrint(r) || r == '\t' // specially treat tab as printable
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}
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line := lines[i]
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isTripleQuoted = !strings.HasPrefix(strings.TrimPrefix(line, prefix), `"""`) && !strings.HasPrefix(line, "...") && strings.TrimFunc(line, isPrintable) == "" && len(line) <= maxLen
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}
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if isTripleQuoted {
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var list textList
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list = append(list, textRecord{Diff: opts.DiffMode, Value: textLine(prefix + `"""`), ElideComma: true})
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for i, line := range lines {
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if numElided := len(lines) - i; i == maxLines-1 && numElided > 1 {
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comment := commentString(fmt.Sprintf("%d elided lines", numElided))
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list = append(list, textRecord{Diff: opts.DiffMode, Value: textEllipsis, ElideComma: true, Comment: comment})
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break
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}
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list = append(list, textRecord{Diff: opts.DiffMode, Value: textLine(line), ElideComma: true})
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}
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list = append(list, textRecord{Diff: opts.DiffMode, Value: textLine(prefix + `"""`), ElideComma: true})
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return &textWrap{Prefix: "(", Value: list, Suffix: ")"}
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}
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// Format the string as a single-line quoted string.
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if len(s) > maxLen+len(textEllipsis) {
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return textLine(prefix + formatString(s[:maxLen]) + string(textEllipsis))
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}
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return textLine(prefix + formatString(s))
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}
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// formatMapKey formats v as if it were a map key.
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// The result is guaranteed to be a single line.
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func formatMapKey(v reflect.Value, disambiguate bool, ptrs *pointerReferences) string {
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var opts formatOptions
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opts.DiffMode = diffIdentical
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opts.TypeMode = elideType
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opts.PrintAddresses = disambiguate
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opts.AvoidStringer = disambiguate
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opts.QualifiedNames = disambiguate
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opts.VerbosityLevel = maxVerbosityPreset
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opts.LimitVerbosity = true
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s := opts.FormatValue(v, reflect.Map, ptrs).String()
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return strings.TrimSpace(s)
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}
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// formatString prints s as a double-quoted or backtick-quoted string.
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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) || r == '\t')
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}
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if utf8.ValidString(s) && 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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// formatHex prints u as a hexadecimal integer in Go notation.
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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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