chore: add aria2 rpc package

pkg/aria2/rpc/proc.go

@@ -0,0 +1,42 @@
+package rpc
+
+import "sync"
+
+type ResponseProcFn func(resp clientResponse) error
+
+type ResponseProcessor struct {
+	cbs map[uint64]ResponseProcFn
+	mu  *sync.RWMutex
+}
+
+func NewResponseProcessor() *ResponseProcessor {
+	return &ResponseProcessor{
+		make(map[uint64]ResponseProcFn),
+		&sync.RWMutex{},
+	}
+}
+
+func (r *ResponseProcessor) Add(id uint64, fn ResponseProcFn) {
+	r.mu.Lock()
+	r.cbs[id] = fn
+	r.mu.Unlock()
+}
+
+func (r *ResponseProcessor) remove(id uint64) {
+	r.mu.Lock()
+	delete(r.cbs, id)
+	r.mu.Unlock()
+}
+
+// Process called by recv routine
+func (r *ResponseProcessor) Process(resp clientResponse) error {
+	id := *resp.Id
+	r.mu.RLock()
+	fn, ok := r.cbs[id]
+	r.mu.RUnlock()
+	if ok && fn != nil {
+		defer r.remove(id)
+		return fn(resp)
+	}
+	return nil
+}