First implementation

vendor/google.golang.org/protobuf/internal/order/order.go

@@ -0,0 +1,89 @@
+// Copyright 2020 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 order
+
+import (
+	pref "google.golang.org/protobuf/reflect/protoreflect"
+)
+
+// FieldOrder specifies the ordering to visit message fields.
+// It is a function that reports whether x is ordered before y.
+type FieldOrder func(x, y pref.FieldDescriptor) bool
+
+var (
+	// AnyFieldOrder specifies no specific field ordering.
+	AnyFieldOrder FieldOrder = nil
+
+	// LegacyFieldOrder sorts fields in the same ordering as emitted by
+	// wire serialization in the github.com/golang/protobuf implementation.
+	LegacyFieldOrder FieldOrder = func(x, y pref.FieldDescriptor) bool {
+		ox, oy := x.ContainingOneof(), y.ContainingOneof()
+		inOneof := func(od pref.OneofDescriptor) bool {
+			return od != nil && !od.IsSynthetic()
+		}
+
+		// Extension fields sort before non-extension fields.
+		if x.IsExtension() != y.IsExtension() {
+			return x.IsExtension() && !y.IsExtension()
+		}
+		// Fields not within a oneof sort before those within a oneof.
+		if inOneof(ox) != inOneof(oy) {
+			return !inOneof(ox) && inOneof(oy)
+		}
+		// Fields in disjoint oneof sets are sorted by declaration index.
+		if ox != nil && oy != nil && ox != oy {
+			return ox.Index() < oy.Index()
+		}
+		// Fields sorted by field number.
+		return x.Number() < y.Number()
+	}
+
+	// NumberFieldOrder sorts fields by their field number.
+	NumberFieldOrder FieldOrder = func(x, y pref.FieldDescriptor) bool {
+		return x.Number() < y.Number()
+	}
+
+	// IndexNameFieldOrder sorts non-extension fields before extension fields.
+	// Non-extensions are sorted according to their declaration index.
+	// Extensions are sorted according to their full name.
+	IndexNameFieldOrder FieldOrder = func(x, y pref.FieldDescriptor) bool {
+		// Non-extension fields sort before extension fields.
+		if x.IsExtension() != y.IsExtension() {
+			return !x.IsExtension() && y.IsExtension()
+		}
+		// Extensions sorted by fullname.
+		if x.IsExtension() && y.IsExtension() {
+			return x.FullName() < y.FullName()
+		}
+		// Non-extensions sorted by declaration index.
+		return x.Index() < y.Index()
+	}
+)
+
+// KeyOrder specifies the ordering to visit map entries.
+// It is a function that reports whether x is ordered before y.
+type KeyOrder func(x, y pref.MapKey) bool
+
+var (
+	// AnyKeyOrder specifies no specific key ordering.
+	AnyKeyOrder KeyOrder = nil
+
+	// GenericKeyOrder sorts false before true, numeric keys in ascending order,
+	// and strings in lexicographical ordering according to UTF-8 codepoints.
+	GenericKeyOrder KeyOrder = func(x, y pref.MapKey) bool {
+		switch x.Interface().(type) {
+		case bool:
+			return !x.Bool() && y.Bool()
+		case int32, int64:
+			return x.Int() < y.Int()
+		case uint32, uint64:
+			return x.Uint() < y.Uint()
+		case string:
+			return x.String() < y.String()
+		default:
+			panic("invalid map key type")
+		}
+	}
+)

vendor/google.golang.org/protobuf/internal/order/range.go

@@ -0,0 +1,115 @@
+// Copyright 2020 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 order provides ordered access to messages and maps.
+package order
+
+import (
+	"sort"
+	"sync"
+
+	pref "google.golang.org/protobuf/reflect/protoreflect"
+)
+
+type messageField struct {
+	fd pref.FieldDescriptor
+	v  pref.Value
+}
+
+var messageFieldPool = sync.Pool{
+	New: func() interface{} { return new([]messageField) },
+}
+
+type (
+	// FieldRnger is an interface for visiting all fields in a message.
+	// The protoreflect.Message type implements this interface.
+	FieldRanger interface{ Range(VisitField) }
+	// VisitField is called everytime a message field is visited.
+	VisitField = func(pref.FieldDescriptor, pref.Value) bool
+)
+
+// RangeFields iterates over the fields of fs according to the specified order.
+func RangeFields(fs FieldRanger, less FieldOrder, fn VisitField) {
+	if less == nil {
+		fs.Range(fn)
+		return
+	}
+
+	// Obtain a pre-allocated scratch buffer.
+	p := messageFieldPool.Get().(*[]messageField)
+	fields := (*p)[:0]
+	defer func() {
+		if cap(fields) < 1024 {
+			*p = fields
+			messageFieldPool.Put(p)
+		}
+	}()
+
+	// Collect all fields in the message and sort them.
+	fs.Range(func(fd pref.FieldDescriptor, v pref.Value) bool {
+		fields = append(fields, messageField{fd, v})
+		return true
+	})
+	sort.Slice(fields, func(i, j int) bool {
+		return less(fields[i].fd, fields[j].fd)
+	})
+
+	// Visit the fields in the specified ordering.
+	for _, f := range fields {
+		if !fn(f.fd, f.v) {
+			return
+		}
+	}
+}
+
+type mapEntry struct {
+	k pref.MapKey
+	v pref.Value
+}
+
+var mapEntryPool = sync.Pool{
+	New: func() interface{} { return new([]mapEntry) },
+}
+
+type (
+	// EntryRanger is an interface for visiting all fields in a message.
+	// The protoreflect.Map type implements this interface.
+	EntryRanger interface{ Range(VisitEntry) }
+	// VisitEntry is called everytime a map entry is visited.
+	VisitEntry = func(pref.MapKey, pref.Value) bool
+)
+
+// RangeEntries iterates over the entries of es according to the specified order.
+func RangeEntries(es EntryRanger, less KeyOrder, fn VisitEntry) {
+	if less == nil {
+		es.Range(fn)
+		return
+	}
+
+	// Obtain a pre-allocated scratch buffer.
+	p := mapEntryPool.Get().(*[]mapEntry)
+	entries := (*p)[:0]
+	defer func() {
+		if cap(entries) < 1024 {
+			*p = entries
+			mapEntryPool.Put(p)
+		}
+	}()
+
+	// Collect all entries in the map and sort them.
+	es.Range(func(k pref.MapKey, v pref.Value) bool {
+		entries = append(entries, mapEntry{k, v})
+		return true
+	})
+	sort.Slice(entries, func(i, j int) bool {
+		return less(entries[i].k, entries[j].k)
+	})
+
+	// Visit the entries in the specified ordering.
+	for _, e := range entries {
+		if !fn(e.k, e.v) {
+			return
+		}
+	}
+}