reflect, internal/reflectlite: embed reflectlite types into reflect types

2026-08-03 02:27:48 +00:00 · 2025-03-08 12:43:53 -08:00
parent bbb2b0c95b
commit d5c70a1cd3
16 changed files with 3868 additions and 3189 deletions
@@ -4,7 +4,7 @@

 // Deep equality test via reflection

-package reflect
+package reflectlite

 import "unsafe"

@@ -15,7 +15,7 @@ import "unsafe"
 type visit struct {
 	a1  unsafe.Pointer
 	a2  unsafe.Pointer
-	typ *rawType
+	typ *RawType
 }

 // Tests for deep equality using reflected types. The map argument tracks
@@ -1,6 +1,6 @@
 //go:build mips

-package reflect
+package reflectlite

 import "unsafe"

@@ -1,6 +1,6 @@
 //go:build !mips

-package reflect
+package reflectlite

 import "unsafe"

@@ -1,6 +1,6 @@
 //go:build !avr

-package reflect
+package reflectlite

 // intw is an integer type, used in places where an int is typically required,
 // except architectures where the size of an int != word size.
@@ -1,6 +1,6 @@
 //go:build avr

-package reflect
+package reflectlite

 // intw is an integer type, used in places where an int is typically required,
 // except architectures where the size of an int != word size.
@@ -1,6 +1,6 @@
 //go:build !avr

-package reflect_test
+package reflectlite_test

 import (
 	"reflect"
@@ -1,3 +1,5 @@
+//go:build never
+
 package reflectlite

 import "reflect"
@@ -0,0 +1,347 @@
+// Copyright 2009 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 reflectlite
+
+import (
+	"unicode/utf8"
+)
+
+// errSyntax indicates that a value does not have the right syntax for the target type.
+var errSyntax = badSyntax{}
+
+type badSyntax struct{}
+
+func (badSyntax) Error() string {
+	return "invalid syntax"
+}
+
+func unhex(b byte) (v rune, ok bool) {
+	c := rune(b)
+	switch {
+	case '0' <= c && c <= '9':
+		return c - '0', true
+	case 'a' <= c && c <= 'f':
+		return c - 'a' + 10, true
+	case 'A' <= c && c <= 'F':
+		return c - 'A' + 10, true
+	}
+	return
+}
+
+const (
+	lowerhex = "0123456789abcef"
+)
+
+// unquoteChar decodes the first character or byte in the escaped string
+// or character literal represented by the string s.
+// It returns four values:
+//
+//  1. value, the decoded Unicode code point or byte value;
+//  2. multibyte, a boolean indicating whether the decoded character requires a multibyte UTF-8 representation;
+//  3. tail, the remainder of the string after the character; and
+//  4. an error that will be nil if the character is syntactically valid.
+//
+// The second argument, quote, specifies the type of literal being parsed
+// and therefore which escaped quote character is permitted.
+// If set to a single quote, it permits the sequence \' and disallows unescaped '.
+// If set to a double quote, it permits \" and disallows unescaped ".
+// If set to zero, it does not permit either escape and allows both quote characters to appear unescaped.
+func unquoteChar(s string, quote byte) (value rune, multibyte bool, tail string, err error) {
+	// easy cases
+	if len(s) == 0 {
+		err = errSyntax
+		return
+	}
+	switch c := s[0]; {
+	case c == quote && (quote == '\'' || quote == '"'):
+		err = errSyntax
+		return
+	case c >= utf8.RuneSelf:
+		r, size := utf8.DecodeRuneInString(s)
+		return r, true, s[size:], nil
+	case c != '\\':
+		return rune(s[0]), false, s[1:], nil
+	}
+
+	// hard case: c is backslash
+	if len(s) <= 1 {
+		err = errSyntax
+		return
+	}
+	c := s[1]
+	s = s[2:]
+
+	switch c {
+	case 'a':
+		value = '\a'
+	case 'b':
+		value = '\b'
+	case 'f':
+		value = '\f'
+	case 'n':
+		value = '\n'
+	case 'r':
+		value = '\r'
+	case 't':
+		value = '\t'
+	case 'v':
+		value = '\v'
+	case 'x', 'u', 'U':
+		n := 0
+		switch c {
+		case 'x':
+			n = 2
+		case 'u':
+			n = 4
+		case 'U':
+			n = 8
+		}
+		var v rune
+		if len(s) < n {
+			err = errSyntax
+			return
+		}
+		for j := 0; j < n; j++ {
+			x, ok := unhex(s[j])
+			if !ok {
+				err = errSyntax
+				return
+			}
+			v = v<<4 | x
+		}
+		s = s[n:]
+		if c == 'x' {
+			// single-byte string, possibly not UTF-8
+			value = v
+			break
+		}
+		if v > utf8.MaxRune {
+			err = errSyntax
+			return
+		}
+		value = v
+		multibyte = true
+	case '0', '1', '2', '3', '4', '5', '6', '7':
+		v := rune(c) - '0'
+		if len(s) < 2 {
+			err = errSyntax
+			return
+		}
+		for j := 0; j < 2; j++ { // one digit already; two more
+			x := rune(s[j]) - '0'
+			if x < 0 || x > 7 {
+				err = errSyntax
+				return
+			}
+			v = (v << 3) | x
+		}
+		s = s[2:]
+		if v > 255 {
+			err = errSyntax
+			return
+		}
+		value = v
+	case '\\':
+		value = '\\'
+	case '\'', '"':
+		if c != quote {
+			err = errSyntax
+			return
+		}
+		value = rune(c)
+	default:
+		err = errSyntax
+		return
+	}
+	tail = s
+	return
+}
+
+// unquote interprets s as a single-quoted, double-quoted,
+// or backquoted Go string literal, returning the string value
+// that s quotes.  (If s is single-quoted, it would be a Go
+// character literal; unquote returns the corresponding
+// one-character string.)
+func unquote(s string) (string, error) {
+	n := len(s)
+	if n < 2 {
+		return "", errSyntax
+	}
+	quote := s[0]
+	if quote != s[n-1] {
+		return "", errSyntax
+	}
+	s = s[1 : n-1]
+
+	if quote == '`' {
+		if contains(s, '`') {
+			return "", errSyntax
+		}
+		if contains(s, '\r') {
+			// -1 because we know there is at least one \r to remove.
+			buf := make([]byte, 0, len(s)-1)
+			for i := 0; i < len(s); i++ {
+				if s[i] != '\r' {
+					buf = append(buf, s[i])
+				}
+			}
+			return string(buf), nil
+		}
+		return s, nil
+	}
+	if quote != '"' && quote != '\'' {
+		return "", errSyntax
+	}
+	if contains(s, '\n') {
+		return "", errSyntax
+	}
+
+	// Is it trivial? Avoid allocation.
+	if !contains(s, '\\') && !contains(s, quote) {
+		switch quote {
+		case '"':
+			if utf8.ValidString(s) {
+				return s, nil
+			}
+		case '\'':
+			r, size := utf8.DecodeRuneInString(s)
+			if size == len(s) && (r != utf8.RuneError || size != 1) {
+				return s, nil
+			}
+		}
+	}
+
+	var runeTmp [utf8.UTFMax]byte
+	buf := make([]byte, 0, 3*len(s)/2) // Try to avoid more allocations.
+	for len(s) > 0 {
+		c, multibyte, ss, err := unquoteChar(s, quote)
+		if err != nil {
+			return "", err
+		}
+		s = ss
+		if c < utf8.RuneSelf || !multibyte {
+			buf = append(buf, byte(c))
+		} else {
+			n := utf8.EncodeRune(runeTmp[:], c)
+			buf = append(buf, runeTmp[:n]...)
+		}
+		if quote == '\'' && len(s) != 0 {
+			// single-quoted must be single character
+			return "", errSyntax
+		}
+	}
+	return string(buf), nil
+}
+
+func quote(s string) string {
+	buf := make([]byte, 0, 3*len(s)/2)
+	const quote = '"'
+
+	buf = append(buf, quote)
+	for width := 0; len(s) > 0; s = s[width:] {
+		r := rune(s[0])
+		width = 1
+		if r >= utf8.RuneSelf {
+			r, width = utf8.DecodeRuneInString(s)
+		}
+		if width == 1 && r == utf8.RuneError {
+			buf = append(buf, `\x`...)
+			buf = append(buf, lowerhex[s[0]>>4])
+			buf = append(buf, lowerhex[s[0]&0xF])
+			continue
+		}
+		buf = appendEscapedRune(buf, r)
+	}
+	buf = append(buf, quote)
+	return string(buf)
+}
+
+func appendEscapedRune(buf []byte, r rune) []byte {
+
+	const quote = '"'
+
+	var runeTmp [utf8.UTFMax]byte
+	if r == rune(quote) || r == '\\' { // always backslashed
+		buf = append(buf, '\\')
+		buf = append(buf, byte(r))
+		return buf
+	}
+	if isPrint(r) {
+		n := utf8.EncodeRune(runeTmp[:], r)
+		buf = append(buf, runeTmp[:n]...)
+		return buf
+	}
+	switch r {
+	case '\a':
+		buf = append(buf, `\a`...)
+	case '\b':
+		buf = append(buf, `\b`...)
+	case '\f':
+		buf = append(buf, `\f`...)
+	case '\n':
+		buf = append(buf, `\n`...)
+	case '\r':
+		buf = append(buf, `\r`...)
+	case '\t':
+		buf = append(buf, `\t`...)
+	case '\v':
+		buf = append(buf, `\v`...)
+	default:
+		switch {
+		case r < ' ' || r == 0x7f:
+			buf = append(buf, `\x`...)
+			buf = append(buf, lowerhex[byte(r)>>4])
+			buf = append(buf, lowerhex[byte(r)&0xF])
+		case !utf8.ValidRune(r):
+			r = 0xFFFD
+			fallthrough
+		case r < 0x10000:
+			buf = append(buf, `\u`...)
+			for s := 12; s >= 0; s -= 4 {
+				buf = append(buf, lowerhex[r>>uint(s)&0xF])
+			}
+		default:
+			buf = append(buf, `\U`...)
+			for s := 28; s >= 0; s -= 4 {
+				buf = append(buf, lowerhex[r>>uint(s)&0xF])
+			}
+		}
+	}
+	return buf
+}
+
+// This is only used for struct tags.  Assume
+func isPrint(r rune) bool {
+	if r <= 0xFF {
+		if 0x20 <= r && r <= 0x7E {
+			// All the ASCII is printable from space through DEL-1.
+			return true
+		}
+		if 0xA1 <= r && r <= 0xFF {
+			// Similarly for ¡ through ÿ...
+			return r != 0xAD // ...except for the bizarre soft hyphen.
+		}
+		return false
+	}
+
+	// TinyGo: Skip all other unicode processing
+	return false
+}
+
+// contains reports whether the string contains the byte c.
+func contains(s string, c byte) bool {
+	return indexByteString(s, c) != -1
+}
+
+// Index finds the index of the first instance of the specified byte in the string.
+// If the byte is not found, this returns -1.
+func indexByteString(s string, c byte) int {
+	for i := 0; i < len(s); i++ {
+		if s[i] == c {
+			return i
+		}
+	}
+	return -1
+}
@@ -0,0 +1,40 @@
+package reflectlite
+
+import "unsafe"
+
+// Some of code here has been copied from the Go sources:
+//   https://github.com/golang/go/blob/go1.15.2/src/reflect/swapper.go
+// It has the following copyright note:
+//
+// 		Copyright 2016 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.
+
+func Swapper(slice interface{}) func(i, j int) {
+	v := ValueOf(slice)
+	if v.Kind() != Slice {
+		panic(&ValueError{Method: "Swapper"})
+	}
+
+	// Just return Nop func if nothing to swap.
+	if v.Len() < 2 {
+		return func(i, j int) {}
+	}
+
+	typ := v.typecode.Elem()
+	size := typ.Size()
+
+	header := (*sliceHeader)(v.value)
+	tmp := unsafe.Pointer(&make([]byte, size)[0])
+
+	return func(i, j int) {
+		if uint(i) >= uint(header.len) || uint(j) >= uint(header.len) {
+			panic("reflect: slice index out of range")
+		}
+		val1 := unsafe.Add(header.data, uintptr(i)*size)
+		val2 := unsafe.Add(header.data, uintptr(j)*size)
+		memcpy(tmp, val1, size)
+		memcpy(val1, val2, size)
+		memcpy(val2, tmp, size)
+	}
+}
@@ -0,0 +1,105 @@
+// Copyright 2021 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 reflectlite
+
+// VisibleFields returns all the visible fields in t, which must be a
+// struct type. A field is defined as visible if it's accessible
+// directly with a FieldByName call. The returned fields include fields
+// inside anonymous struct members and unexported fields. They follow
+// the same order found in the struct, with anonymous fields followed
+// immediately by their promoted fields.
+//
+// For each element e of the returned slice, the corresponding field
+// can be retrieved from a value v of type t by calling v.FieldByIndex(e.Index).
+func VisibleFields(t Type) []StructField {
+	if t == nil {
+		panic("reflect: VisibleFields(nil)")
+	}
+	if t.Kind() != Struct {
+		panic("reflect.VisibleFields of non-struct type")
+	}
+	w := &visibleFieldsWalker{
+		byName:   make(map[string]int),
+		visiting: make(map[Type]bool),
+		fields:   make([]StructField, 0, t.NumField()),
+		index:    make([]int, 0, 2),
+	}
+	w.walk(t)
+	// Remove all the fields that have been hidden.
+	// Use an in-place removal that avoids copying in
+	// the common case that there are no hidden fields.
+	j := 0
+	for i := range w.fields {
+		f := &w.fields[i]
+		if f.Name == "" {
+			continue
+		}
+		if i != j {
+			// A field has been removed. We need to shuffle
+			// all the subsequent elements up.
+			w.fields[j] = *f
+		}
+		j++
+	}
+	return w.fields[:j]
+}
+
+type visibleFieldsWalker struct {
+	byName   map[string]int
+	visiting map[Type]bool
+	fields   []StructField
+	index    []int
+}
+
+// walk walks all the fields in the struct type t, visiting
+// fields in index preorder and appending them to w.fields
+// (this maintains the required ordering).
+// Fields that have been overridden have their
+// Name field cleared.
+func (w *visibleFieldsWalker) walk(t Type) {
+	if w.visiting[t] {
+		return
+	}
+	w.visiting[t] = true
+	for i := 0; i < t.NumField(); i++ {
+		f := t.Field(i)
+		w.index = append(w.index, i)
+		add := true
+		if oldIndex, ok := w.byName[f.Name]; ok {
+			old := &w.fields[oldIndex]
+			if len(w.index) == len(old.Index) {
+				// Fields with the same name at the same depth
+				// cancel one another out. Set the field name
+				// to empty to signify that has happened, and
+				// there's no need to add this field.
+				old.Name = ""
+				add = false
+			} else if len(w.index) < len(old.Index) {
+				// The old field loses because it's deeper than the new one.
+				old.Name = ""
+			} else {
+				// The old field wins because it's shallower than the new one.
+				add = false
+			}
+		}
+		if add {
+			// Copy the index so that it's not overwritten
+			// by the other appends.
+			f.Index = append([]int(nil), w.index...)
+			w.byName[f.Name] = len(w.fields)
+			w.fields = append(w.fields, f)
+		}
+		if f.Anonymous {
+			if f.Type.Kind() == Pointer {
+				f.Type = f.Type.Elem()
+			}
+			if f.Type.Kind() == Struct {
+				w.walk(f.Type)
+			}
+		}
+		w.index = w.index[:len(w.index)-1]
+	}
+	delete(w.visiting, t)
+}
@@ -1,40 +1,7 @@
 package reflect

-import "unsafe"
-
-// Some of code here has been copied from the Go sources:
-//   https://github.com/golang/go/blob/go1.15.2/src/reflect/swapper.go
-// It has the following copyright note:
-//
-// 		Copyright 2016 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.
+import "internal/reflectlite"

 func Swapper(slice interface{}) func(i, j int) {
-	v := ValueOf(slice)
-	if v.Kind() != Slice {
-		panic(&ValueError{Method: "Swapper"})
-	}
-
-	// Just return Nop func if nothing to swap.
-	if v.Len() < 2 {
-		return func(i, j int) {}
-	}
-
-	typ := v.typecode.Elem()
-	size := typ.Size()
-
-	header := (*sliceHeader)(v.value)
-	tmp := unsafe.Pointer(&make([]byte, size)[0])
-
-	return func(i, j int) {
-		if uint(i) >= uint(header.len) || uint(j) >= uint(header.len) {
-			panic("reflect: slice index out of range")
-		}
-		val1 := unsafe.Add(header.data, uintptr(i)*size)
-		val2 := unsafe.Add(header.data, uintptr(j)*size)
-		memcpy(tmp, val1, size)
-		memcpy(val1, val2, size)
-		memcpy(val2, tmp, size)
-	}
+	return reflectlite.Swapper(slice)
 }
@@ -1,105 +1,7 @@
-// Copyright 2021 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 reflect

-// VisibleFields returns all the visible fields in t, which must be a
-// struct type. A field is defined as visible if it's accessible
-// directly with a FieldByName call. The returned fields include fields
-// inside anonymous struct members and unexported fields. They follow
-// the same order found in the struct, with anonymous fields followed
-// immediately by their promoted fields.
-//
-// For each element e of the returned slice, the corresponding field
-// can be retrieved from a value v of type t by calling v.FieldByIndex(e.Index).
+import "internal/reflectlite"
+
 func VisibleFields(t Type) []StructField {
-	if t == nil {
-		panic("reflect: VisibleFields(nil)")
-	}
-	if t.Kind() != Struct {
-		panic("reflect.VisibleFields of non-struct type")
-	}
-	w := &visibleFieldsWalker{
-		byName:   make(map[string]int),
-		visiting: make(map[Type]bool),
-		fields:   make([]StructField, 0, t.NumField()),
-		index:    make([]int, 0, 2),
-	}
-	w.walk(t)
-	// Remove all the fields that have been hidden.
-	// Use an in-place removal that avoids copying in
-	// the common case that there are no hidden fields.
-	j := 0
-	for i := range w.fields {
-		f := &w.fields[i]
-		if f.Name == "" {
-			continue
-		}
-		if i != j {
-			// A field has been removed. We need to shuffle
-			// all the subsequent elements up.
-			w.fields[j] = *f
-		}
-		j++
-	}
-	return w.fields[:j]
-}
-
-type visibleFieldsWalker struct {
-	byName   map[string]int
-	visiting map[Type]bool
-	fields   []StructField
-	index    []int
-}
-
-// walk walks all the fields in the struct type t, visiting
-// fields in index preorder and appending them to w.fields
-// (this maintains the required ordering).
-// Fields that have been overridden have their
-// Name field cleared.
-func (w *visibleFieldsWalker) walk(t Type) {
-	if w.visiting[t] {
-		return
-	}
-	w.visiting[t] = true
-	for i := 0; i < t.NumField(); i++ {
-		f := t.Field(i)
-		w.index = append(w.index, i)
-		add := true
-		if oldIndex, ok := w.byName[f.Name]; ok {
-			old := &w.fields[oldIndex]
-			if len(w.index) == len(old.Index) {
-				// Fields with the same name at the same depth
-				// cancel one another out. Set the field name
-				// to empty to signify that has happened, and
-				// there's no need to add this field.
-				old.Name = ""
-				add = false
-			} else if len(w.index) < len(old.Index) {
-				// The old field loses because it's deeper than the new one.
-				old.Name = ""
-			} else {
-				// The old field wins because it's shallower than the new one.
-				add = false
-			}
-		}
-		if add {
-			// Copy the index so that it's not overwritten
-			// by the other appends.
-			f.Index = append([]int(nil), w.index...)
-			w.byName[f.Name] = len(w.fields)
-			w.fields = append(w.fields, f)
-		}
-		if f.Anonymous {
-			if f.Type.Kind() == Pointer {
-				f.Type = f.Type.Elem()
-			}
-			if f.Type.Kind() == Struct {
-				w.walk(f.Type)
-			}
-		}
-		w.index = w.index[:len(w.index)-1]
-	}
-	delete(w.visiting, t)
+	return reflectlite.VisibleFields(toRawType(t))
 }