| // 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 file. |
| |
| package cmp |
| |
| import ( |
| "bytes" |
| "fmt" |
| "reflect" |
| "strconv" |
| "strings" |
| "unicode" |
| "unicode/utf8" |
| |
| "github.com/google/go-cmp/cmp/internal/value" |
| ) |
| |
| var ( |
| anyType = reflect.TypeOf((*interface{})(nil)).Elem() |
| stringType = reflect.TypeOf((*string)(nil)).Elem() |
| bytesType = reflect.TypeOf((*[]byte)(nil)).Elem() |
| byteType = reflect.TypeOf((*byte)(nil)).Elem() |
| ) |
| |
| type formatValueOptions struct { |
| // AvoidStringer controls whether to avoid calling custom stringer |
| // methods like error.Error or fmt.Stringer.String. |
| AvoidStringer bool |
| |
| // PrintAddresses controls whether to print the address of all pointers, |
| // slice elements, and maps. |
| PrintAddresses bool |
| |
| // QualifiedNames controls whether FormatType uses the fully qualified name |
| // (including the full package path as opposed to just the package name). |
| QualifiedNames bool |
| |
| // VerbosityLevel controls the amount of output to produce. |
| // A higher value produces more output. A value of zero or lower produces |
| // no output (represented using an ellipsis). |
| // If LimitVerbosity is false, then the level is treated as infinite. |
| VerbosityLevel int |
| |
| // LimitVerbosity specifies that formatting should respect VerbosityLevel. |
| LimitVerbosity bool |
| } |
| |
| // FormatType prints the type as if it were wrapping s. |
| // This may return s as-is depending on the current type and TypeMode mode. |
| func (opts formatOptions) FormatType(t reflect.Type, s textNode) textNode { |
| // Check whether to emit the type or not. |
| switch opts.TypeMode { |
| case autoType: |
| switch t.Kind() { |
| case reflect.Struct, reflect.Slice, reflect.Array, reflect.Map: |
| if s.Equal(textNil) { |
| return s |
| } |
| default: |
| return s |
| } |
| if opts.DiffMode == diffIdentical { |
| return s // elide type for identical nodes |
| } |
| case elideType: |
| return s |
| } |
| |
| // Determine the type label, applying special handling for unnamed types. |
| typeName := value.TypeString(t, opts.QualifiedNames) |
| if t.Name() == "" { |
| // According to Go grammar, certain type literals contain symbols that |
| // do not strongly bind to the next lexicographical token (e.g., *T). |
| switch t.Kind() { |
| case reflect.Chan, reflect.Func, reflect.Ptr: |
| typeName = "(" + typeName + ")" |
| } |
| } |
| return &textWrap{Prefix: typeName, Value: wrapParens(s)} |
| } |
| |
| // wrapParens wraps s with a set of parenthesis, but avoids it if the |
| // wrapped node itself is already surrounded by a pair of parenthesis or braces. |
| // It handles unwrapping one level of pointer-reference nodes. |
| func wrapParens(s textNode) textNode { |
| var refNode *textWrap |
| if s2, ok := s.(*textWrap); ok { |
| // Unwrap a single pointer reference node. |
| switch s2.Metadata.(type) { |
| case leafReference, trunkReference, trunkReferences: |
| refNode = s2 |
| if s3, ok := refNode.Value.(*textWrap); ok { |
| s2 = s3 |
| } |
| } |
| |
| // Already has delimiters that make parenthesis unnecessary. |
| hasParens := strings.HasPrefix(s2.Prefix, "(") && strings.HasSuffix(s2.Suffix, ")") |
| hasBraces := strings.HasPrefix(s2.Prefix, "{") && strings.HasSuffix(s2.Suffix, "}") |
| if hasParens || hasBraces { |
| return s |
| } |
| } |
| if refNode != nil { |
| refNode.Value = &textWrap{Prefix: "(", Value: refNode.Value, Suffix: ")"} |
| return s |
| } |
| return &textWrap{Prefix: "(", Value: s, Suffix: ")"} |
| } |
| |
| // FormatValue prints the reflect.Value, taking extra care to avoid descending |
| // into pointers already in ptrs. As pointers are visited, ptrs is also updated. |
| func (opts formatOptions) FormatValue(v reflect.Value, parentKind reflect.Kind, ptrs *pointerReferences) (out textNode) { |
| if !v.IsValid() { |
| return nil |
| } |
| t := v.Type() |
| |
| // Check slice element for cycles. |
| if parentKind == reflect.Slice { |
| ptrRef, visited := ptrs.Push(v.Addr()) |
| if visited { |
| return makeLeafReference(ptrRef, false) |
| } |
| defer ptrs.Pop() |
| defer func() { out = wrapTrunkReference(ptrRef, false, out) }() |
| } |
| |
| // Check whether there is an Error or String method to call. |
| if !opts.AvoidStringer && v.CanInterface() { |
| // Avoid calling Error or String methods on nil receivers since many |
| // implementations crash when doing so. |
| if (t.Kind() != reflect.Ptr && t.Kind() != reflect.Interface) || !v.IsNil() { |
| var prefix, strVal string |
| func() { |
| // Swallow and ignore any panics from String or Error. |
| defer func() { recover() }() |
| switch v := v.Interface().(type) { |
| case error: |
| strVal = v.Error() |
| prefix = "e" |
| case fmt.Stringer: |
| strVal = v.String() |
| prefix = "s" |
| } |
| }() |
| if prefix != "" { |
| return opts.formatString(prefix, strVal) |
| } |
| } |
| } |
| |
| // Check whether to explicitly wrap the result with the type. |
| var skipType bool |
| defer func() { |
| if !skipType { |
| out = opts.FormatType(t, out) |
| } |
| }() |
| |
| switch t.Kind() { |
| case reflect.Bool: |
| return textLine(fmt.Sprint(v.Bool())) |
| case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64: |
| return textLine(fmt.Sprint(v.Int())) |
| case reflect.Uint, reflect.Uint16, reflect.Uint32, reflect.Uint64: |
| return textLine(fmt.Sprint(v.Uint())) |
| case reflect.Uint8: |
| if parentKind == reflect.Slice || parentKind == reflect.Array { |
| return textLine(formatHex(v.Uint())) |
| } |
| return textLine(fmt.Sprint(v.Uint())) |
| case reflect.Uintptr: |
| return textLine(formatHex(v.Uint())) |
| case reflect.Float32, reflect.Float64: |
| return textLine(fmt.Sprint(v.Float())) |
| case reflect.Complex64, reflect.Complex128: |
| return textLine(fmt.Sprint(v.Complex())) |
| case reflect.String: |
| return opts.formatString("", v.String()) |
| case reflect.UnsafePointer, reflect.Chan, reflect.Func: |
| return textLine(formatPointer(value.PointerOf(v), true)) |
| case reflect.Struct: |
| var list textList |
| v := makeAddressable(v) // needed for retrieveUnexportedField |
| maxLen := v.NumField() |
| if opts.LimitVerbosity { |
| maxLen = ((1 << opts.verbosity()) >> 1) << 2 // 0, 4, 8, 16, 32, etc... |
| opts.VerbosityLevel-- |
| } |
| for i := 0; i < v.NumField(); i++ { |
| vv := v.Field(i) |
| if vv.IsZero() { |
| continue // Elide fields with zero values |
| } |
| if len(list) == maxLen { |
| list.AppendEllipsis(diffStats{}) |
| break |
| } |
| sf := t.Field(i) |
| if !isExported(sf.Name) { |
| vv = retrieveUnexportedField(v, sf, true) |
| } |
| s := opts.WithTypeMode(autoType).FormatValue(vv, t.Kind(), ptrs) |
| list = append(list, textRecord{Key: sf.Name, Value: s}) |
| } |
| return &textWrap{Prefix: "{", Value: list, Suffix: "}"} |
| case reflect.Slice: |
| if v.IsNil() { |
| return textNil |
| } |
| |
| // Check whether this is a []byte of text data. |
| if t.Elem() == byteType { |
| b := v.Bytes() |
| isPrintSpace := func(r rune) bool { return unicode.IsPrint(r) || unicode.IsSpace(r) } |
| if len(b) > 0 && utf8.Valid(b) && len(bytes.TrimFunc(b, isPrintSpace)) == 0 { |
| out = opts.formatString("", string(b)) |
| skipType = true |
| return opts.FormatType(t, out) |
| } |
| } |
| |
| fallthrough |
| case reflect.Array: |
| maxLen := v.Len() |
| if opts.LimitVerbosity { |
| maxLen = ((1 << opts.verbosity()) >> 1) << 2 // 0, 4, 8, 16, 32, etc... |
| opts.VerbosityLevel-- |
| } |
| var list textList |
| for i := 0; i < v.Len(); i++ { |
| if len(list) == maxLen { |
| list.AppendEllipsis(diffStats{}) |
| break |
| } |
| s := opts.WithTypeMode(elideType).FormatValue(v.Index(i), t.Kind(), ptrs) |
| list = append(list, textRecord{Value: s}) |
| } |
| |
| out = &textWrap{Prefix: "{", Value: list, Suffix: "}"} |
| if t.Kind() == reflect.Slice && opts.PrintAddresses { |
| header := fmt.Sprintf("ptr:%v, len:%d, cap:%d", formatPointer(value.PointerOf(v), false), v.Len(), v.Cap()) |
| out = &textWrap{Prefix: pointerDelimPrefix + header + pointerDelimSuffix, Value: out} |
| } |
| return out |
| case reflect.Map: |
| if v.IsNil() { |
| return textNil |
| } |
| |
| // Check pointer for cycles. |
| ptrRef, visited := ptrs.Push(v) |
| if visited { |
| return makeLeafReference(ptrRef, opts.PrintAddresses) |
| } |
| defer ptrs.Pop() |
| |
| maxLen := v.Len() |
| if opts.LimitVerbosity { |
| maxLen = ((1 << opts.verbosity()) >> 1) << 2 // 0, 4, 8, 16, 32, etc... |
| opts.VerbosityLevel-- |
| } |
| var list textList |
| for _, k := range value.SortKeys(v.MapKeys()) { |
| if len(list) == maxLen { |
| list.AppendEllipsis(diffStats{}) |
| break |
| } |
| sk := formatMapKey(k, false, ptrs) |
| sv := opts.WithTypeMode(elideType).FormatValue(v.MapIndex(k), t.Kind(), ptrs) |
| list = append(list, textRecord{Key: sk, Value: sv}) |
| } |
| |
| out = &textWrap{Prefix: "{", Value: list, Suffix: "}"} |
| out = wrapTrunkReference(ptrRef, opts.PrintAddresses, out) |
| return out |
| case reflect.Ptr: |
| if v.IsNil() { |
| return textNil |
| } |
| |
| // Check pointer for cycles. |
| ptrRef, visited := ptrs.Push(v) |
| if visited { |
| out = makeLeafReference(ptrRef, opts.PrintAddresses) |
| return &textWrap{Prefix: "&", Value: out} |
| } |
| defer ptrs.Pop() |
| |
| // Skip the name only if this is an unnamed pointer type. |
| // Otherwise taking the address of a value does not reproduce |
| // the named pointer type. |
| if v.Type().Name() == "" { |
| skipType = true // Let the underlying value print the type instead |
| } |
| out = opts.FormatValue(v.Elem(), t.Kind(), ptrs) |
| out = wrapTrunkReference(ptrRef, opts.PrintAddresses, out) |
| out = &textWrap{Prefix: "&", Value: out} |
| return out |
| case reflect.Interface: |
| if v.IsNil() { |
| return textNil |
| } |
| // Interfaces accept different concrete types, |
| // so configure the underlying value to explicitly print the type. |
| return opts.WithTypeMode(emitType).FormatValue(v.Elem(), t.Kind(), ptrs) |
| default: |
| panic(fmt.Sprintf("%v kind not handled", v.Kind())) |
| } |
| } |
| |
| func (opts formatOptions) formatString(prefix, s string) textNode { |
| maxLen := len(s) |
| maxLines := strings.Count(s, "\n") + 1 |
| if opts.LimitVerbosity { |
| maxLen = (1 << opts.verbosity()) << 5 // 32, 64, 128, 256, etc... |
| maxLines = (1 << opts.verbosity()) << 2 // 4, 8, 16, 32, 64, etc... |
| } |
| |
| // For multiline strings, use the triple-quote syntax, |
| // but only use it when printing removed or inserted nodes since |
| // we only want the extra verbosity for those cases. |
| lines := strings.Split(strings.TrimSuffix(s, "\n"), "\n") |
| isTripleQuoted := len(lines) >= 4 && (opts.DiffMode == '-' || opts.DiffMode == '+') |
| for i := 0; i < len(lines) && isTripleQuoted; i++ { |
| lines[i] = strings.TrimPrefix(strings.TrimSuffix(lines[i], "\r"), "\r") // trim leading/trailing carriage returns for legacy Windows endline support |
| isPrintable := func(r rune) bool { |
| return unicode.IsPrint(r) || r == '\t' // specially treat tab as printable |
| } |
| line := lines[i] |
| isTripleQuoted = !strings.HasPrefix(strings.TrimPrefix(line, prefix), `"""`) && !strings.HasPrefix(line, "...") && strings.TrimFunc(line, isPrintable) == "" && len(line) <= maxLen |
| } |
| if isTripleQuoted { |
| var list textList |
| list = append(list, textRecord{Diff: opts.DiffMode, Value: textLine(prefix + `"""`), ElideComma: true}) |
| for i, line := range lines { |
| if numElided := len(lines) - i; i == maxLines-1 && numElided > 1 { |
| comment := commentString(fmt.Sprintf("%d elided lines", numElided)) |
| list = append(list, textRecord{Diff: opts.DiffMode, Value: textEllipsis, ElideComma: true, Comment: comment}) |
| break |
| } |
| list = append(list, textRecord{Diff: opts.DiffMode, Value: textLine(line), ElideComma: true}) |
| } |
| list = append(list, textRecord{Diff: opts.DiffMode, Value: textLine(prefix + `"""`), ElideComma: true}) |
| return &textWrap{Prefix: "(", Value: list, Suffix: ")"} |
| } |
| |
| // Format the string as a single-line quoted string. |
| if len(s) > maxLen+len(textEllipsis) { |
| return textLine(prefix + formatString(s[:maxLen]) + string(textEllipsis)) |
| } |
| return textLine(prefix + formatString(s)) |
| } |
| |
| // formatMapKey formats v as if it were a map key. |
| // The result is guaranteed to be a single line. |
| func formatMapKey(v reflect.Value, disambiguate bool, ptrs *pointerReferences) string { |
| var opts formatOptions |
| opts.DiffMode = diffIdentical |
| opts.TypeMode = elideType |
| opts.PrintAddresses = disambiguate |
| opts.AvoidStringer = disambiguate |
| opts.QualifiedNames = disambiguate |
| opts.VerbosityLevel = maxVerbosityPreset |
| opts.LimitVerbosity = true |
| s := opts.FormatValue(v, reflect.Map, ptrs).String() |
| return strings.TrimSpace(s) |
| } |
| |
| // formatString prints s as a double-quoted or backtick-quoted string. |
| func formatString(s string) string { |
| // Use quoted string if it the same length as a raw string literal. |
| // Otherwise, attempt to use the raw string form. |
| qs := strconv.Quote(s) |
| if len(qs) == 1+len(s)+1 { |
| return qs |
| } |
| |
| // Disallow newlines to ensure output is a single line. |
| // Only allow printable runes for readability purposes. |
| rawInvalid := func(r rune) bool { |
| return r == '`' || r == '\n' || !(unicode.IsPrint(r) || r == '\t') |
| } |
| if utf8.ValidString(s) && strings.IndexFunc(s, rawInvalid) < 0 { |
| return "`" + s + "`" |
| } |
| return qs |
| } |
| |
| // formatHex prints u as a hexadecimal integer in Go notation. |
| func formatHex(u uint64) string { |
| var f string |
| switch { |
| case u <= 0xff: |
| f = "0x%02x" |
| case u <= 0xffff: |
| f = "0x%04x" |
| case u <= 0xffffff: |
| f = "0x%06x" |
| case u <= 0xffffffff: |
| f = "0x%08x" |
| case u <= 0xffffffffff: |
| f = "0x%010x" |
| case u <= 0xffffffffffff: |
| f = "0x%012x" |
| case u <= 0xffffffffffffff: |
| f = "0x%014x" |
| case u <= 0xffffffffffffffff: |
| f = "0x%016x" |
| } |
| return fmt.Sprintf(f, u) |
| } |