ui/app/internal/gpu: add specialized path cache to avoid key allocations

Signed-off-by: Elias Naur <mail@eliasnaur.com>

ui/app/internal/gpu/caches.go

@@ -0,0 +1,107 @@
+package gpu
+
+import (
+	"fmt"
+
+	"gioui.org/ui"
+)
+
+type resourceCache struct {
+	res    map[interface{}]resource
+	newRes map[interface{}]resource
+}
+
+// opCache is like a resourceCache using the concrete OpKey
+// key type to avoid allocations.
+type opCache struct {
+	res    map[ui.OpKey]resource
+	newRes map[ui.OpKey]resource
+}
+
+func newResourceCache() *resourceCache {
+	return &resourceCache{
+		res:    make(map[interface{}]resource),
+		newRes: make(map[interface{}]resource),
+	}
+}
+
+func (r *resourceCache) get(key interface{}) (resource, bool) {
+	v, exists := r.res[key]
+	if exists {
+		r.newRes[key] = v
+	}
+	return v, exists
+}
+
+func (r *resourceCache) put(key interface{}, val resource) {
+	if _, exists := r.newRes[key]; exists {
+		panic(fmt.Errorf("key exists, %p", key))
+	}
+	r.res[key] = val
+	r.newRes[key] = val
+}
+
+func (r *resourceCache) frame(ctx *context) {
+	for k, v := range r.res {
+		if _, exists := r.newRes[k]; !exists {
+			delete(r.res, k)
+			v.release(ctx)
+		}
+	}
+	for k, v := range r.newRes {
+		delete(r.newRes, k)
+		r.res[k] = v
+	}
+}
+
+func (r *resourceCache) release(ctx *context) {
+	for _, v := range r.newRes {
+		v.release(ctx)
+	}
+	r.newRes = nil
+	r.res = nil
+}
+
+func newOpCache() *opCache {
+	return &opCache{
+		res:    make(map[ui.OpKey]resource),
+		newRes: make(map[ui.OpKey]resource),
+	}
+}
+
+func (r *opCache) get(key ui.OpKey) (resource, bool) {
+	v, exists := r.res[key]
+	if exists {
+		r.newRes[key] = v
+	}
+	return v, exists
+}
+
+func (r *opCache) put(key ui.OpKey, val resource) {
+	if _, exists := r.newRes[key]; exists {
+		panic(fmt.Errorf("key exists, %p", key))
+	}
+	r.res[key] = val
+	r.newRes[key] = val
+}
+
+func (r *opCache) frame(ctx *context) {
+	for k, v := range r.res {
+		if _, exists := r.newRes[k]; !exists {
+			delete(r.res, k)
+			v.release(ctx)
+		}
+	}
+	for k, v := range r.newRes {
+		delete(r.newRes, k)
+		r.res[k] = v
+	}
+}
+
+func (r *opCache) release(ctx *context) {
+	for _, v := range r.newRes {
+		v.release(ctx)
+	}
+	r.newRes = nil
+	r.res = nil
+}