Add storage backends and safety checks

internal/storage/registry.go

@@ -0,0 +1,46 @@
+package storage
+
+import (
+	"context"
+	"sync"
+)
+
+type OpenConfig map[string]string
+
+type Opener func(context.Context, OpenConfig) (Backend, error)
+
+type Registry struct {
+	mu      sync.RWMutex
+	openers map[string]Opener
+}
+
+func NewRegistry() *Registry {
+	return &Registry{openers: make(map[string]Opener)}
+}
+
+func (r *Registry) Register(name string, opener Opener) error {
+	if name == "" || opener == nil {
+		return NewError(OpRegisterBackend, name, "", ErrInvalidPath, nil)
+	}
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	if _, exists := r.openers[name]; exists {
+		return NewError(OpRegisterBackend, name, "", ErrAlreadyExist, nil)
+	}
+	r.openers[name] = opener
+	return nil
+}
+
+func (r *Registry) Open(ctx context.Context, name string, cfg OpenConfig) (Backend, error) {
+	r.mu.RLock()
+	opener, ok := r.openers[name]
+	r.mu.RUnlock()
+	if !ok {
+		return nil, NewError(OpOpenBackend, name, "", ErrUnsupported, nil)
+	}
+	backend, err := opener(ctx, cfg)
+	if err != nil {
+		return nil, err
+	}
+	return backend, nil
+}