Move struct-handling to internal/jsonstruct

8 files changed, 66 insertions, 60 deletions

diff --git a/borrowed_misc.go b/borrowed_misc.go
index b84158b..59c49aa 100644
--- a/borrowed_misc.go
+++ b/borrowed_misc.go
@@ -8,8 +8,6 @@ package lowmemjson
 
 import (
 	"reflect"
-	"strings"
-	"unicode"
 )
 
 // isEmptyValue is borrowed from encode.go.
@@ -30,21 +28,3 @@ func isEmptyValue(v reflect.Value) bool {
 	}
 	return false
 }
-
-// isValidTag is borrowed from encode.go.
-func isValidTag(s string) bool {
-	if s == "" {
-		return false
-	}
-	for _, c := range s {
-		switch {
-		case strings.ContainsRune("!#$%&()*+-./:;<=>?@[]^_{|}~ ", c):
-			// Backslash and quote chars are reserved, but
-			// otherwise any punctuation chars are allowed
-			// in a tag name.
-		case !unicode.IsLetter(c) && !unicode.IsDigit(c):
-			return false
-		}
-	}
-	return true
-}
diff --git a/compat/json/compat_test.go b/compat/json/compat_test.go
index 4b167d1..2969107 100644
--- a/compat/json/compat_test.go
+++ b/compat/json/compat_test.go
@@ -10,11 +10,11 @@ import (
 
 	"git.lukeshu.com/go/lowmemjson"
 	"git.lukeshu.com/go/lowmemjson/internal/jsonparse"
-	"git.lukeshu.com/go/lowmemjson/internal/jsontags"
+	"git.lukeshu.com/go/lowmemjson/internal/jsonstruct"
 	"git.lukeshu.com/go/lowmemjson/internal/jsontest"
 )
 
-var parseTag = jsontags.ParseTag
+var parseTag = jsonstruct.ParseTag
 
 type scanner = lowmemjson.ReEncoderConfig
 
diff --git a/decode.go b/decode.go
index 3a9a4b1..487bce4 100644
--- a/decode.go
+++ b/decode.go
@@ -26,6 +26,7 @@ import (
 	"git.lukeshu.com/go/lowmemjson/internal/base64dec"
 	"git.lukeshu.com/go/lowmemjson/internal/fastio"
 	"git.lukeshu.com/go/lowmemjson/internal/jsonparse"
+	"git.lukeshu.com/go/lowmemjson/internal/jsonstruct"
 )
 
 // Decodable is the interface implemented by types that can decode a
@@ -532,7 +533,7 @@ func (dec *Decoder) decode(val reflect.Value, nullOK bool) {
 				dec.decodeNull()
 				return
 			}
-			index := indexStruct(typ)
+			index := jsonstruct.IndexStruct(typ)
 			var nameBuf strings.Builder
 			dec.decodeObject(typ, func() {
 				dec.posStackPush()
@@ -545,10 +546,10 @@ func (dec *Decoder) decode(val reflect.Value, nullOK bool) {
 				name := nameBuf.String()
 				dec.structStackPush(typ, name)
 				defer dec.structStackPop()
-				idx, ok := index.byName[name]
+				idx, ok := index.ByName[name]
 				if !ok {
-					for oidx := range index.byPos {
-						if strings.EqualFold(name, index.byPos[oidx].Name) {
+					for oidx := range index.ByPos {
+						if strings.EqualFold(name, index.ByPos[oidx].Name) {
 							idx = oidx
 							ok = true
 							break
@@ -562,7 +563,7 @@ func (dec *Decoder) decode(val reflect.Value, nullOK bool) {
 					dec.scan(fastio.Discard)
 					return
 				}
-				field := index.byPos[idx]
+				field := index.ByPos[idx]
 				fVal := val
 				for _, idx := range field.Path {
 					if fVal.Kind() == reflect.Pointer {
diff --git a/encode.go b/encode.go
index ca4e060..fa558b9 100644
--- a/encode.go
+++ b/encode.go
@@ -16,6 +16,8 @@ import (
 	"strconv"
 	"strings"
 	"unsafe"
+
+	"git.lukeshu.com/go/lowmemjson/internal/jsonstruct"
 )
 
 // Encodable is the interface implemented by types that can encode
@@ -299,7 +301,7 @@ func encode(w *ReEncoder, val reflect.Value, escaper BackslashEscaper, quote boo
 				return err
 			}
 			empty := true
-			for _, field := range indexStruct(val.Type()).byPos {
+			for _, field := range jsonstruct.IndexStruct(val.Type()).ByPos {
 				fVal, err := val.FieldByIndexErr(field.Path)
 				if err != nil {
 					continue
diff --git a/internal/jsonstruct/borrowed_misc.go b/internal/jsonstruct/borrowed_misc.go
new file mode 100644
index 0000000..3b4181e
--- /dev/null
+++ b/internal/jsonstruct/borrowed_misc.go
@@ -0,0 +1,30 @@
+// Copyright 2010 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.
+//
+// SPDX-License-Identifier: BSD-3-Clause
+
+package jsonstruct
+
+import (
+	"strings"
+	"unicode"
+)
+
+// isValidTag is borrowed from encode.go.
+func isValidTag(s string) bool {
+	if s == "" {
+		return false
+	}
+	for _, c := range s {
+		switch {
+		case strings.ContainsRune("!#$%&()*+-./:;<=>?@[]^_{|}~ ", c):
+			// Backslash and quote chars are reserved, but
+			// otherwise any punctuation chars are allowed
+			// in a tag name.
+		case !unicode.IsLetter(c) && !unicode.IsDigit(c):
+			return false
+		}
+	}
+	return true
+}
diff --git a/internal/jsontags/borrowed_tags.go b/internal/jsonstruct/borrowed_tags.go
index aa94b9b..f2ef71c 100644
--- a/internal/jsontags/borrowed_tags.go
+++ b/internal/jsonstruct/borrowed_tags.go
@@ -4,7 +4,7 @@
 //
 // SPDX-License-Identifier: BSD-3-Clause
 
-package jsontags // MODIFIED: changed package name
+package jsonstruct // MODIFIED: changed package name
 
 import (
 	"strings"
diff --git a/struct.go b/internal/jsonstruct/struct.go
index 5ccb62f..830dc80 100644
--- a/struct.go
+++ b/internal/jsonstruct/struct.go
@@ -2,17 +2,17 @@
 //
 // SPDX-License-Identifier: GPL-2.0-or-later
 
-package lowmemjson
+package jsonstruct
 
 import (
 	"reflect"
 
 	"git.lukeshu.com/go/typedsync"
-
-	"git.lukeshu.com/go/lowmemjson/internal/jsontags"
 )
 
-type structField struct {
+var ParseTag = parseTag
+
+type StructField struct {
 	Name      string
 	Path      []int
 	Tagged    bool
@@ -20,33 +20,33 @@ type structField struct {
 	Quote     bool
 }
 
-// A structIndex is used by Decoder.Decode() and Encoder.Encode() when
+// A StructIndex is used by Decoder.Decode() and Encoder.Encode() when
 // decoding-to or encoding-from a struct.
-type structIndex struct {
-	byPos  []structField
-	byName map[string]int
+type StructIndex struct {
+	ByPos  []StructField
+	ByName map[string]int
 }
 
-var structIndexCache typedsync.CacheMap[reflect.Type, structIndex]
+var structIndexCache typedsync.CacheMap[reflect.Type, StructIndex]
 
-// indexStruct takes a struct Type, and indexes its fields for use by
+// IndexStruct takes a struct Type, and indexes its fields for use by
 // Decoder.Decode() and Encoder.Encode().  indexStruct caches its
 // results.
-func indexStruct(typ reflect.Type) structIndex {
+func IndexStruct(typ reflect.Type) StructIndex {
 	ret, _ := structIndexCache.LoadOrCompute(typ, indexStructReal)
 	return ret
 }
 
 // indexStructReal is like indexStruct, but is the real indexer,
 // bypassing the cache.
-func indexStructReal(typ reflect.Type) structIndex {
-	var byPos []structField
+func indexStructReal(typ reflect.Type) StructIndex {
+	var byPos []StructField
 	byName := make(map[string][]int)
 
 	indexStructInner(typ, &byPos, byName, nil, map[reflect.Type]struct{}{})
 
-	ret := structIndex{
-		byName: make(map[string]int),
+	ret := StructIndex{
+		ByName: make(map[string]int),
 	}
 
 	for curPos, _field := range byPos {
@@ -56,8 +56,8 @@ func indexStructReal(typ reflect.Type) structIndex {
 		case 0:
 			// do nothing
 		case 1:
-			ret.byName[name] = len(ret.byPos)
-			ret.byPos = append(ret.byPos, _field)
+			ret.ByName[name] = len(ret.ByPos)
+			ret.ByPos = append(ret.ByPos, _field)
 		default:
 			// To quote the encoding/json docs (version 1.18.4):
 			//
@@ -106,14 +106,14 @@ func indexStructReal(typ reflect.Type) structIndex {
 					// do nothing
 				case 1:
 					if curPos == untaggedPos {
-						ret.byName[name] = len(ret.byPos)
-						ret.byPos = append(ret.byPos, byPos[curPos])
+						ret.ByName[name] = len(ret.ByPos)
+						ret.ByPos = append(ret.ByPos, byPos[curPos])
 					}
 				}
 			case 1:
 				if curPos == taggedPos {
-					ret.byName[name] = len(ret.byPos)
-					ret.byPos = append(ret.byPos, byPos[curPos])
+					ret.ByName[name] = len(ret.ByPos)
+					ret.ByPos = append(ret.ByPos, byPos[curPos])
 				}
 			}
 		}
@@ -128,7 +128,7 @@ func indexStructReal(typ reflect.Type) structIndex {
 // call itself; keeping track of stack information with `stackPath`
 // (which identifies where we are in the parent struct) and
 // `stackSeen` (which is used for detecting loops).
-func indexStructInner(typ reflect.Type, byPos *[]structField, byName map[string][]int, stackPath []int, stackSeen map[reflect.Type]struct{}) {
+func indexStructInner(typ reflect.Type, byPos *[]StructField, byName map[string][]int, stackPath []int, stackSeen map[reflect.Type]struct{}) {
 	if _, ok := stackSeen[typ]; ok {
 		return
 	}
@@ -157,7 +157,7 @@ func indexStructInner(typ reflect.Type, byPos *[]structField, byName map[string]
 		if tag == "-" {
 			continue
 		}
-		tagName, opts := jsontags.ParseTag(tag)
+		tagName, opts := parseTag(tag)
 		name := tagName
 		if !isValidTag(name) {
 			name = ""
@@ -174,7 +174,7 @@ func indexStructInner(typ reflect.Type, byPos *[]structField, byName map[string]
 			indexStructInner(t, byPos, byName, stackPath, stackSeen)
 		} else {
 			byName[name] = append(byName[name], len(*byPos))
-			*byPos = append(*byPos, structField{
+			*byPos = append(*byPos, StructField{
 				Name:      name,
 				Path:      append([]int(nil), stackPath...),
 				Tagged:    tagName != "",
diff --git a/internal/jsontags/tags.go b/internal/jsontags/tags.go
deleted file mode 100644
index 386824d..0000000
--- a/internal/jsontags/tags.go
+++ /dev/null
@@ -1,7 +0,0 @@
-// Copyright (C) 2022-2023  Luke Shumaker <lukeshu@lukeshu.com>
-//
-// SPDX-License-Identifier: GPL-2.0-or-later
-
-package jsontags
-
-var ParseTag = parseTag