internal/impl: optimize reflect methods
This change performs two optimizations:
* It uses a pre-constructed rangeInfos slice to iterate over
all the fields. This is more performant since iterating over a slice
is faster than iterating over a map. Furthermore, this slice
does not contain fields that are part of a oneof. If a oneof has
N fields, the time to check presence on the oneof is now O(1)
instead of O(N).
* It uses a dense field info slice that is optmized for the common
case where the field number is relatively low and close in value
to the index itself.
We also fix a minor bug in the construction of oneofInfo where
it wasn't treating a typed nil pointer to a wrapper struct as if
it were unset. This ensures WhichOneof and Has always agree.
name old time/op new time/op delta
Reflect/Has-4 7.81µs ± 3% 6.74µs ± 3% -13.61% (p=0.000 n=9+9)
Reflect/Get-4 12.7µs ± 1% 11.3µs ± 4% -10.85% (p=0.000 n=8+10)
Reflect/Set-4 19.5µs ± 5% 17.8µs ± 2% -8.99% (p=0.000 n=10+10)
Reflect/Clear-4 12.0µs ± 4% 10.2µs ± 3% -14.86% (p=0.000 n=9+10)
Reflect/Range-4 6.58µs ± 1% 4.17µs ± 2% -36.65% (p=0.000 n=8+9)
Change-Id: I2c48b4d3fb6103ab238924950529ded0d37f8c8a
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/196358
Reviewed-by: Damien Neil <dneil@google.com>
diff --git a/internal/impl/message_reflect_gen.go b/internal/impl/message_reflect_gen.go
index 574fb4f..1c56375 100644
--- a/internal/impl/message_reflect_gen.go
+++ b/internal/impl/message_reflect_gen.go
@@ -42,10 +42,20 @@
func (m *messageState) Range(f func(protoreflect.FieldDescriptor, protoreflect.Value) bool) {
m.messageInfo().init()
- for _, fi := range m.messageInfo().fields {
- if fi.has(m.pointer()) {
- if !f(fi.fieldDesc, fi.get(m.pointer())) {
- return
+ for _, ri := range m.messageInfo().rangeInfos {
+ switch ri := ri.(type) {
+ case *fieldInfo:
+ if ri.has(m.pointer()) {
+ if !f(ri.fieldDesc, ri.get(m.pointer())) {
+ return
+ }
+ }
+ case *oneofInfo:
+ if n := ri.which(m.pointer()); n > 0 {
+ fi := m.messageInfo().fields[n]
+ if !f(fi.fieldDesc, fi.get(m.pointer())) {
+ return
+ }
}
}
}
@@ -149,10 +159,20 @@
func (m *messageReflectWrapper) Range(f func(protoreflect.FieldDescriptor, protoreflect.Value) bool) {
m.messageInfo().init()
- for _, fi := range m.messageInfo().fields {
- if fi.has(m.pointer()) {
- if !f(fi.fieldDesc, fi.get(m.pointer())) {
- return
+ for _, ri := range m.messageInfo().rangeInfos {
+ switch ri := ri.(type) {
+ case *fieldInfo:
+ if ri.has(m.pointer()) {
+ if !f(ri.fieldDesc, ri.get(m.pointer())) {
+ return
+ }
+ }
+ case *oneofInfo:
+ if n := ri.which(m.pointer()); n > 0 {
+ fi := m.messageInfo().fields[n]
+ if !f(fi.fieldDesc, fi.get(m.pointer())) {
+ return
+ }
}
}
}