First Commit

1 files changed, 138 insertions, 0 deletions

diff --git a/conn.go b/conn.go
new file mode 100644
index 0000000..d88744c
--- /dev/null
+++ b/conn.go
@@ -0,0 +1,138 @@
+package cache
+
+import (
+	"errors"
+	"os"
+	"sync"
+	"time"
+
+	"github.com/vmihailenco/msgpack"
+)
+
+type DB[K any, V any] struct {
+	file  *os.File
+	Store Store
+	stop  chan struct{}
+	wg    sync.WaitGroup
+}
+
+func OpenFile[K any, V any](filename string) (*DB[K, V], error) {
+	ret := &DB[K, V]{}
+	file, err := os.OpenFile(filename, os.O_RDWR, 0)
+	if errors.Is(err, os.ErrNotExist) {
+		file, err := os.Create(filename)
+		if err != nil {
+			return nil, err
+		}
+		ret.file = file
+		ret.SetStratergy(StrategyNone)
+		ret.Clear()
+		ret.Flush()
+	} else if err == nil {
+		ret.Clear()
+		ret.file = file
+		ret.Store.LoadSnapshot(ret.file)
+	} else {
+		return nil, err
+	}
+	ret.wg.Add(1)
+	go ret.backgroundWorker()
+	return ret, nil
+}
+
+func OpenMem[K any, V any]() *DB[K, V] {
+	ret := &DB[K, V]{}
+	ret.SetStratergy(StrategyNone)
+	ret.Clear()
+	return ret
+}
+
+func (d *DB[K, V]) SetStratergy(e EvictionPolicy) error {
+	strategy, err := e.ToStratergy(&d.Store.evict)
+	if err != nil {
+		return err
+	}
+	d.Store.strategy = strategy
+	return nil
+}
+
+func (d *DB[K, V]) SetMaxCost(e EvictionPolicy) {
+	d.Store.max_cost = d.Store.max_cost
+}
+
+func (d *DB[K, V]) backgroundWorker() {
+	defer d.wg.Done()
+	for {
+		select {
+		case <-d.stop:
+			return
+			// TODO: Do house keeping
+		}
+	}
+}
+
+func (d *DB[K, V]) Close() {
+	close(d.stop)
+	d.wg.Wait()
+	d.Flush()
+	d.Clear()
+	if d.file != nil {
+		d.file.Close()
+	}
+}
+
+func (d *DB[K, V]) Flush() error {
+	if d.file != nil {
+		return d.Store.Snapshot(d.file)
+	}
+	return nil
+}
+
+func (d *DB[K, V]) Clear() {
+	d.Store.Clear()
+}
+
+var ErrKeyNotFound = errors.New("key not found")
+
+func (h *DB[K, V]) Get(key K) (V, time.Duration, error) {
+	keyData, err := msgpack.Marshal(key)
+	if err != nil {
+		return zero[V](), 0, err
+	}
+
+	v, ttl, ok := h.Store.Get(keyData)
+	if !ok {
+		return zero[V](), 0, ErrKeyNotFound
+	}
+
+	var ret V
+	if err = msgpack.Unmarshal(v, &ret); err != nil {
+		return zero[V](), 0, err
+	}
+	return ret, ttl, err
+}
+
+func (h *DB[K, V]) Set(key K, value V, ttl time.Duration) error {
+	keyData, err := msgpack.Marshal(key)
+	if err != nil {
+		return err
+	}
+	valueData, err := msgpack.Marshal(value)
+	if err != nil {
+		return err
+	}
+	h.Store.Set(keyData, valueData, ttl)
+	return nil
+}
+
+func (h *DB[K, V]) Delete(key K) error {
+	keyData, err := msgpack.Marshal(key)
+	if err != nil {
+		return err
+	}
+	ok := h.Store.Delete(keyData)
+	if !ok {
+		return ErrKeyNotFound
+	}
+	return nil
+}