blob: c8090e0c547f6c6e9eed09ea8c4340bbc61cb0f2 [file] [log] [blame]
// 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
}
}
}