@@ -332,10 +332,7 @@ type encOpts struct {
332332
333333type encoderFunc func (e * encodeState , v reflect.Value , opts encOpts )
334334
335- var encoderCache struct {
336- sync.RWMutex
337- m map [reflect.Type ]encoderFunc
338- }
335+ var encoderCache sync.Map // map[reflect.Type]encoderFunc
339336
340337func valueEncoder (v reflect.Value ) encoderFunc {
341338 if ! v .IsValid () {
@@ -345,36 +342,31 @@ func valueEncoder(v reflect.Value) encoderFunc {
345342}
346343
347344func typeEncoder (t reflect.Type ) encoderFunc {
348- encoderCache .RLock ()
349- f := encoderCache .m [t ]
350- encoderCache .RUnlock ()
351- if f != nil {
352- return f
345+ if fi , ok := encoderCache .Load (t ); ok {
346+ return fi .(encoderFunc )
353347 }
354348
355349 // To deal with recursive types, populate the map with an
356350 // indirect func before we build it. This type waits on the
357351 // real func (f) to be ready and then calls it. This indirect
358352 // func is only used for recursive types.
359- encoderCache .Lock ()
360- if encoderCache .m == nil {
361- encoderCache .m = make (map [reflect.Type ]encoderFunc )
362- }
363- var wg sync.WaitGroup
353+ var (
354+ wg sync.WaitGroup
355+ f encoderFunc
356+ )
364357 wg .Add (1 )
365- encoderCache .m [ t ] = func (e * encodeState , v reflect.Value , opts encOpts ) {
358+ fi , loaded := encoderCache .LoadOrStore ( t , encoderFunc ( func (e * encodeState , v reflect.Value , opts encOpts ) {
366359 wg .Wait ()
367360 f (e , v , opts )
361+ }))
362+ if loaded {
363+ return fi .(encoderFunc )
368364 }
369- encoderCache .Unlock ()
370365
371- // Compute fields without lock.
372- // Might duplicate effort but won't hold other computations back.
366+ // Compute the real encoder and replace the indirect func with it.
373367 f = newTypeEncoder (t , true )
374368 wg .Done ()
375- encoderCache .Lock ()
376- encoderCache .m [t ] = f
377- encoderCache .Unlock ()
369+ encoderCache .Store (t , f )
378370 return f
379371}
380372
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