+++ /dev/null
-// Copyright 2019, The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE.md file.
-
-package cmp
-
-import (
- "fmt"
- "reflect"
-
- "github.com/google/go-cmp/cmp/internal/value"
-)
-
-// numContextRecords is the number of surrounding equal records to print.
-const numContextRecords = 2
-
-type diffMode byte
-
-const (
- diffUnknown diffMode = 0
- diffIdentical diffMode = ' '
- diffRemoved diffMode = '-'
- diffInserted diffMode = '+'
-)
-
-type typeMode int
-
-const (
- // emitType always prints the type.
- emitType typeMode = iota
- // elideType never prints the type.
- elideType
- // autoType prints the type only for composite kinds
- // (i.e., structs, slices, arrays, and maps).
- autoType
-)
-
-type formatOptions struct {
- // DiffMode controls the output mode of FormatDiff.
- //
- // If diffUnknown, then produce a diff of the x and y values.
- // If diffIdentical, then emit values as if they were equal.
- // If diffRemoved, then only emit x values (ignoring y values).
- // If diffInserted, then only emit y values (ignoring x values).
- DiffMode diffMode
-
- // TypeMode controls whether to print the type for the current node.
- //
- // As a general rule of thumb, we always print the type of the next node
- // after an interface, and always elide the type of the next node after
- // a slice or map node.
- TypeMode typeMode
-
- // formatValueOptions are options specific to printing reflect.Values.
- formatValueOptions
-}
-
-func (opts formatOptions) WithDiffMode(d diffMode) formatOptions {
- opts.DiffMode = d
- return opts
-}
-func (opts formatOptions) WithTypeMode(t typeMode) formatOptions {
- opts.TypeMode = t
- return opts
-}
-func (opts formatOptions) WithVerbosity(level int) formatOptions {
- opts.VerbosityLevel = level
- opts.LimitVerbosity = true
- return opts
-}
-func (opts formatOptions) verbosity() uint {
- switch {
- case opts.VerbosityLevel < 0:
- return 0
- case opts.VerbosityLevel > 16:
- return 16 // some reasonable maximum to avoid shift overflow
- default:
- return uint(opts.VerbosityLevel)
- }
-}
-
-const maxVerbosityPreset = 3
-
-// verbosityPreset modifies the verbosity settings given an index
-// between 0 and maxVerbosityPreset, inclusive.
-func verbosityPreset(opts formatOptions, i int) formatOptions {
- opts.VerbosityLevel = int(opts.verbosity()) + 2*i
- if i > 0 {
- opts.AvoidStringer = true
- }
- if i >= maxVerbosityPreset {
- opts.PrintAddresses = true
- opts.QualifiedNames = true
- }
- return opts
-}
-
-// FormatDiff converts a valueNode tree into a textNode tree, where the later
-// is a textual representation of the differences detected in the former.
-func (opts formatOptions) FormatDiff(v *valueNode, ptrs *pointerReferences) (out textNode) {
- if opts.DiffMode == diffIdentical {
- opts = opts.WithVerbosity(1)
- } else {
- opts = opts.WithVerbosity(3)
- }
-
- // Check whether we have specialized formatting for this node.
- // This is not necessary, but helpful for producing more readable outputs.
- if opts.CanFormatDiffSlice(v) {
- return opts.FormatDiffSlice(v)
- }
-
- var parentKind reflect.Kind
- if v.parent != nil && v.parent.TransformerName == "" {
- parentKind = v.parent.Type.Kind()
- }
-
- // For leaf nodes, format the value based on the reflect.Values alone.
- if v.MaxDepth == 0 {
- switch opts.DiffMode {
- case diffUnknown, diffIdentical:
- // Format Equal.
- if v.NumDiff == 0 {
- outx := opts.FormatValue(v.ValueX, parentKind, ptrs)
- outy := opts.FormatValue(v.ValueY, parentKind, ptrs)
- if v.NumIgnored > 0 && v.NumSame == 0 {
- return textEllipsis
- } else if outx.Len() < outy.Len() {
- return outx
- } else {
- return outy
- }
- }
-
- // Format unequal.
- assert(opts.DiffMode == diffUnknown)
- var list textList
- outx := opts.WithTypeMode(elideType).FormatValue(v.ValueX, parentKind, ptrs)
- outy := opts.WithTypeMode(elideType).FormatValue(v.ValueY, parentKind, ptrs)
- for i := 0; i <= maxVerbosityPreset && outx != nil && outy != nil && outx.Equal(outy); i++ {
- opts2 := verbosityPreset(opts, i).WithTypeMode(elideType)
- outx = opts2.FormatValue(v.ValueX, parentKind, ptrs)
- outy = opts2.FormatValue(v.ValueY, parentKind, ptrs)
- }
- if outx != nil {
- list = append(list, textRecord{Diff: '-', Value: outx})
- }
- if outy != nil {
- list = append(list, textRecord{Diff: '+', Value: outy})
- }
- return opts.WithTypeMode(emitType).FormatType(v.Type, list)
- case diffRemoved:
- return opts.FormatValue(v.ValueX, parentKind, ptrs)
- case diffInserted:
- return opts.FormatValue(v.ValueY, parentKind, ptrs)
- default:
- panic("invalid diff mode")
- }
- }
-
- // Register slice element to support cycle detection.
- if parentKind == reflect.Slice {
- ptrRefs := ptrs.PushPair(v.ValueX, v.ValueY, opts.DiffMode, true)
- defer ptrs.Pop()
- defer func() { out = wrapTrunkReferences(ptrRefs, out) }()
- }
-
- // Descend into the child value node.
- if v.TransformerName != "" {
- out := opts.WithTypeMode(emitType).FormatDiff(v.Value, ptrs)
- out = &textWrap{Prefix: "Inverse(" + v.TransformerName + ", ", Value: out, Suffix: ")"}
- return opts.FormatType(v.Type, out)
- } else {
- switch k := v.Type.Kind(); k {
- case reflect.Struct, reflect.Array, reflect.Slice:
- out = opts.formatDiffList(v.Records, k, ptrs)
- out = opts.FormatType(v.Type, out)
- case reflect.Map:
- // Register map to support cycle detection.
- ptrRefs := ptrs.PushPair(v.ValueX, v.ValueY, opts.DiffMode, false)
- defer ptrs.Pop()
-
- out = opts.formatDiffList(v.Records, k, ptrs)
- out = wrapTrunkReferences(ptrRefs, out)
- out = opts.FormatType(v.Type, out)
- case reflect.Ptr:
- // Register pointer to support cycle detection.
- ptrRefs := ptrs.PushPair(v.ValueX, v.ValueY, opts.DiffMode, false)
- defer ptrs.Pop()
-
- out = opts.FormatDiff(v.Value, ptrs)
- out = wrapTrunkReferences(ptrRefs, out)
- out = &textWrap{Prefix: "&", Value: out}
- case reflect.Interface:
- out = opts.WithTypeMode(emitType).FormatDiff(v.Value, ptrs)
- default:
- panic(fmt.Sprintf("%v cannot have children", k))
- }
- return out
- }
-}
-
-func (opts formatOptions) formatDiffList(recs []reportRecord, k reflect.Kind, ptrs *pointerReferences) textNode {
- // Derive record name based on the data structure kind.
- var name string
- var formatKey func(reflect.Value) string
- switch k {
- case reflect.Struct:
- name = "field"
- opts = opts.WithTypeMode(autoType)
- formatKey = func(v reflect.Value) string { return v.String() }
- case reflect.Slice, reflect.Array:
- name = "element"
- opts = opts.WithTypeMode(elideType)
- formatKey = func(reflect.Value) string { return "" }
- case reflect.Map:
- name = "entry"
- opts = opts.WithTypeMode(elideType)
- formatKey = func(v reflect.Value) string { return formatMapKey(v, false, ptrs) }
- }
-
- maxLen := -1
- if opts.LimitVerbosity {
- if opts.DiffMode == diffIdentical {
- maxLen = ((1 << opts.verbosity()) >> 1) << 2 // 0, 4, 8, 16, 32, etc...
- } else {
- maxLen = (1 << opts.verbosity()) << 1 // 2, 4, 8, 16, 32, 64, etc...
- }
- opts.VerbosityLevel--
- }
-
- // Handle unification.
- switch opts.DiffMode {
- case diffIdentical, diffRemoved, diffInserted:
- var list textList
- var deferredEllipsis bool // Add final "..." to indicate records were dropped
- for _, r := range recs {
- if len(list) == maxLen {
- deferredEllipsis = true
- break
- }
-
- // Elide struct fields that are zero value.
- if k == reflect.Struct {
- var isZero bool
- switch opts.DiffMode {
- case diffIdentical:
- isZero = value.IsZero(r.Value.ValueX) || value.IsZero(r.Value.ValueY)
- case diffRemoved:
- isZero = value.IsZero(r.Value.ValueX)
- case diffInserted:
- isZero = value.IsZero(r.Value.ValueY)
- }
- if isZero {
- continue
- }
- }
- // Elide ignored nodes.
- if r.Value.NumIgnored > 0 && r.Value.NumSame+r.Value.NumDiff == 0 {
- deferredEllipsis = !(k == reflect.Slice || k == reflect.Array)
- if !deferredEllipsis {
- list.AppendEllipsis(diffStats{})
- }
- continue
- }
- if out := opts.FormatDiff(r.Value, ptrs); out != nil {
- list = append(list, textRecord{Key: formatKey(r.Key), Value: out})
- }
- }
- if deferredEllipsis {
- list.AppendEllipsis(diffStats{})
- }
- return &textWrap{Prefix: "{", Value: list, Suffix: "}"}
- case diffUnknown:
- default:
- panic("invalid diff mode")
- }
-
- // Handle differencing.
- var numDiffs int
- var list textList
- var keys []reflect.Value // invariant: len(list) == len(keys)
- groups := coalesceAdjacentRecords(name, recs)
- maxGroup := diffStats{Name: name}
- for i, ds := range groups {
- if maxLen >= 0 && numDiffs >= maxLen {
- maxGroup = maxGroup.Append(ds)
- continue
- }
-
- // Handle equal records.
- if ds.NumDiff() == 0 {
- // Compute the number of leading and trailing records to print.
- var numLo, numHi int
- numEqual := ds.NumIgnored + ds.NumIdentical
- for numLo < numContextRecords && numLo+numHi < numEqual && i != 0 {
- if r := recs[numLo].Value; r.NumIgnored > 0 && r.NumSame+r.NumDiff == 0 {
- break
- }
- numLo++
- }
- for numHi < numContextRecords && numLo+numHi < numEqual && i != len(groups)-1 {
- if r := recs[numEqual-numHi-1].Value; r.NumIgnored > 0 && r.NumSame+r.NumDiff == 0 {
- break
- }
- numHi++
- }
- if numEqual-(numLo+numHi) == 1 && ds.NumIgnored == 0 {
- numHi++ // Avoid pointless coalescing of a single equal record
- }
-
- // Format the equal values.
- for _, r := range recs[:numLo] {
- out := opts.WithDiffMode(diffIdentical).FormatDiff(r.Value, ptrs)
- list = append(list, textRecord{Key: formatKey(r.Key), Value: out})
- keys = append(keys, r.Key)
- }
- if numEqual > numLo+numHi {
- ds.NumIdentical -= numLo + numHi
- list.AppendEllipsis(ds)
- for len(keys) < len(list) {
- keys = append(keys, reflect.Value{})
- }
- }
- for _, r := range recs[numEqual-numHi : numEqual] {
- out := opts.WithDiffMode(diffIdentical).FormatDiff(r.Value, ptrs)
- list = append(list, textRecord{Key: formatKey(r.Key), Value: out})
- keys = append(keys, r.Key)
- }
- recs = recs[numEqual:]
- continue
- }
-
- // Handle unequal records.
- for _, r := range recs[:ds.NumDiff()] {
- switch {
- case opts.CanFormatDiffSlice(r.Value):
- out := opts.FormatDiffSlice(r.Value)
- list = append(list, textRecord{Key: formatKey(r.Key), Value: out})
- keys = append(keys, r.Key)
- case r.Value.NumChildren == r.Value.MaxDepth:
- outx := opts.WithDiffMode(diffRemoved).FormatDiff(r.Value, ptrs)
- outy := opts.WithDiffMode(diffInserted).FormatDiff(r.Value, ptrs)
- for i := 0; i <= maxVerbosityPreset && outx != nil && outy != nil && outx.Equal(outy); i++ {
- opts2 := verbosityPreset(opts, i)
- outx = opts2.WithDiffMode(diffRemoved).FormatDiff(r.Value, ptrs)
- outy = opts2.WithDiffMode(diffInserted).FormatDiff(r.Value, ptrs)
- }
- if outx != nil {
- list = append(list, textRecord{Diff: diffRemoved, Key: formatKey(r.Key), Value: outx})
- keys = append(keys, r.Key)
- }
- if outy != nil {
- list = append(list, textRecord{Diff: diffInserted, Key: formatKey(r.Key), Value: outy})
- keys = append(keys, r.Key)
- }
- default:
- out := opts.FormatDiff(r.Value, ptrs)
- list = append(list, textRecord{Key: formatKey(r.Key), Value: out})
- keys = append(keys, r.Key)
- }
- }
- recs = recs[ds.NumDiff():]
- numDiffs += ds.NumDiff()
- }
- if maxGroup.IsZero() {
- assert(len(recs) == 0)
- } else {
- list.AppendEllipsis(maxGroup)
- for len(keys) < len(list) {
- keys = append(keys, reflect.Value{})
- }
- }
- assert(len(list) == len(keys))
-
- // For maps, the default formatting logic uses fmt.Stringer which may
- // produce ambiguous output. Avoid calling String to disambiguate.
- if k == reflect.Map {
- var ambiguous bool
- seenKeys := map[string]reflect.Value{}
- for i, currKey := range keys {
- if currKey.IsValid() {
- strKey := list[i].Key
- prevKey, seen := seenKeys[strKey]
- if seen && prevKey.CanInterface() && currKey.CanInterface() {
- ambiguous = prevKey.Interface() != currKey.Interface()
- if ambiguous {
- break
- }
- }
- seenKeys[strKey] = currKey
- }
- }
- if ambiguous {
- for i, k := range keys {
- if k.IsValid() {
- list[i].Key = formatMapKey(k, true, ptrs)
- }
- }
- }
- }
-
- return &textWrap{Prefix: "{", Value: list, Suffix: "}"}
-}
-
-// coalesceAdjacentRecords coalesces the list of records into groups of
-// adjacent equal, or unequal counts.
-func coalesceAdjacentRecords(name string, recs []reportRecord) (groups []diffStats) {
- var prevCase int // Arbitrary index into which case last occurred
- lastStats := func(i int) *diffStats {
- if prevCase != i {
- groups = append(groups, diffStats{Name: name})
- prevCase = i
- }
- return &groups[len(groups)-1]
- }
- for _, r := range recs {
- switch rv := r.Value; {
- case rv.NumIgnored > 0 && rv.NumSame+rv.NumDiff == 0:
- lastStats(1).NumIgnored++
- case rv.NumDiff == 0:
- lastStats(1).NumIdentical++
- case rv.NumDiff > 0 && !rv.ValueY.IsValid():
- lastStats(2).NumRemoved++
- case rv.NumDiff > 0 && !rv.ValueX.IsValid():
- lastStats(2).NumInserted++
- default:
- lastStats(2).NumModified++
- }
- }
- return groups
-}
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