feat: field mask util.
This commit is contained in:
tx7do
210
fieldmaskutil/fieldmaskutil.go
Normal file
210
fieldmaskutil/fieldmaskutil.go
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@@ -0,0 +1,210 @@
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package fieldmaskutil
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import (
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"google.golang.org/protobuf/proto"
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"google.golang.org/protobuf/reflect/protoreflect"
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)
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// Filter keeps the msg fields that are listed in the paths and clears all the rest.
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//
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// This is a handy wrapper for NestedMask.Filter method.
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// If the same paths are used to process multiple proto messages use NestedMask.Filter method directly.
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func Filter(msg proto.Message, paths []string) {
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NestedMaskFromPaths(paths).Filter(msg)
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}
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// Prune clears all the fields listed in paths from the given msg.
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//
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// This is a handy wrapper for NestedMask.Prune method.
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// If the same paths are used to process multiple proto messages use NestedMask.Filter method directly.
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func Prune(msg proto.Message, paths []string) {
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NestedMaskFromPaths(paths).Prune(msg)
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}
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// Overwrite overwrites all the fields listed in paths in the dest msg using values from src msg.
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//
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// This is a handy wrapper for NestedMask.Overwrite method.
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// If the same paths are used to process multiple proto messages use NestedMask.Overwrite method directly.
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func Overwrite(src, dest proto.Message, paths []string) {
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NestedMaskFromPaths(paths).Overwrite(src, dest)
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}
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// NestedMask represents a field mask as a recursive map.
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type NestedMask map[string]NestedMask
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// NestedMaskFromPaths creates an instance of NestedMask for the given paths.
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func NestedMaskFromPaths(paths []string) NestedMask {
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mask := make(NestedMask)
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for _, path := range paths {
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curr := mask
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var letters []rune
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for _, letter := range path {
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if letter == '.' {
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if len(letters) == 0 {
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continue
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}
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key := string(letters)
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c, ok := curr[key]
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if !ok {
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c = make(NestedMask)
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curr[key] = c
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}
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curr = c
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letters = nil
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continue
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}
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letters = append(letters, letter)
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}
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if len(letters) != 0 {
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key := string(letters)
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if _, ok := curr[key]; !ok {
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curr[key] = make(NestedMask)
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}
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}
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}
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return mask
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}
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// Filter keeps the msg fields that are listed in the paths and clears all the rest.
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//
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// If the mask is empty then all the fields are kept.
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// Paths are assumed to be valid and normalized otherwise the function may panic.
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// See google.golang.org/protobuf/types/known/fieldmaskpb for details.
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func (mask NestedMask) Filter(msg proto.Message) {
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if len(mask) == 0 {
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return
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}
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rft := msg.ProtoReflect()
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rft.Range(func(fd protoreflect.FieldDescriptor, _ protoreflect.Value) bool {
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m, ok := mask[string(fd.Name())]
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if ok {
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if len(m) == 0 {
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return true
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}
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if fd.IsMap() {
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xmap := rft.Get(fd).Map()
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xmap.Range(func(mk protoreflect.MapKey, mv protoreflect.Value) bool {
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if mi, ok := m[mk.String()]; ok {
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if i, ok := mv.Interface().(protoreflect.Message); ok && len(mi) > 0 {
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mi.Filter(i.Interface())
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}
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} else {
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xmap.Clear(mk)
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}
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return true
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})
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} else if fd.IsList() {
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list := rft.Get(fd).List()
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for i := 0; i < list.Len(); i++ {
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m.Filter(list.Get(i).Message().Interface())
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}
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} else if fd.Kind() == protoreflect.MessageKind {
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m.Filter(rft.Get(fd).Message().Interface())
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}
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} else {
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rft.Clear(fd)
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}
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return true
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})
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}
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// Prune clears all the fields listed in paths from the given msg.
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//
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// All other fields are kept untouched. If the mask is empty no fields are cleared.
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// This operation is the opposite of NestedMask.Filter.
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// Paths are assumed to be valid and normalized otherwise the function may panic.
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// See google.golang.org/protobuf/types/known/fieldmaskpb for details.
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func (mask NestedMask) Prune(msg proto.Message) {
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if len(mask) == 0 {
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return
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}
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rft := msg.ProtoReflect()
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rft.Range(func(fd protoreflect.FieldDescriptor, _ protoreflect.Value) bool {
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m, ok := mask[string(fd.Name())]
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if ok {
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if len(m) == 0 {
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rft.Clear(fd)
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return true
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}
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if fd.IsMap() {
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xmap := rft.Get(fd).Map()
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xmap.Range(func(mk protoreflect.MapKey, mv protoreflect.Value) bool {
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if mi, ok := m[mk.String()]; ok {
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if i, ok := mv.Interface().(protoreflect.Message); ok && len(mi) > 0 {
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mi.Prune(i.Interface())
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} else {
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xmap.Clear(mk)
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}
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}
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return true
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})
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} else if fd.IsList() {
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list := rft.Get(fd).List()
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for i := 0; i < list.Len(); i++ {
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m.Prune(list.Get(i).Message().Interface())
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}
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} else if fd.Kind() == protoreflect.MessageKind {
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m.Prune(rft.Get(fd).Message().Interface())
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}
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}
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return true
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})
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}
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// Overwrite overwrites all the fields listed in paths in the dest msg using values from src msg.
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//
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// All other fields are kept untouched. If the mask is empty, no fields are overwritten.
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// Supports scalars, messages, repeated fields, and maps.
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// If the parent of the field is nil message, the parent is initiated before overwriting the field
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// If the field in src is empty value, the field in dest is cleared.
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// Paths are assumed to be valid and normalized otherwise the function may panic.
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func (mask NestedMask) Overwrite(src, dest proto.Message) {
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mask.overwrite(src.ProtoReflect(), dest.ProtoReflect())
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}
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func (mask NestedMask) overwrite(src, dest protoreflect.Message) {
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for k, v := range mask {
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srcFD := src.Descriptor().Fields().ByName(protoreflect.Name(k))
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destFD := dest.Descriptor().Fields().ByName(protoreflect.Name(k))
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if srcFD == nil || destFD == nil {
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continue
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}
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// Leaf mask -> copy value from src to dest
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if len(v) == 0 {
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if srcFD.Kind() == destFD.Kind() { // TODO: Full type equality check
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val := src.Get(srcFD)
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if isValid(srcFD, val) {
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dest.Set(destFD, val)
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} else {
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dest.Clear(destFD)
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}
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}
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} else if srcFD.Kind() == protoreflect.MessageKind {
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// If dest field is nil
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if !dest.Get(destFD).Message().IsValid() {
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dest.Set(destFD, protoreflect.ValueOf(dest.Get(destFD).Message().New()))
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}
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v.overwrite(src.Get(srcFD).Message(), dest.Get(destFD).Message())
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}
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}
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}
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func isValid(fd protoreflect.FieldDescriptor, val protoreflect.Value) bool {
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if fd.IsMap() {
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return val.Map().IsValid()
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} else if fd.IsList() {
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return val.List().IsValid()
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} else if fd.Message() != nil {
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return val.Message().IsValid()
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}
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return true
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}
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