initial commit

pkg/fs/metadata.go

@@ -0,0 +1,52 @@
+// Copyright (C) 2022 Marius Schellenberger
+
+package fs
+
+import (
+	"os"
+	"sync"
+)
+
+type Metadata struct {
+	mu      sync.RWMutex `json:"-"`
+	f       *os.File     `json:"-"`
+	Size    int64        `json:"s"`
+	Chunks  Chunks       `json:"c"`
+	preload bool         `json:"-"`
+}
+
+func (md *Metadata) HasChunk(off int64, n int) bool {
+	md.mu.RLock()
+	defer md.mu.RUnlock()
+	return md.Chunks.Exists(off, n, md.Size)
+}
+
+func (md *Metadata) AddChunk(off int64, n int) {
+	md.mu.Lock()
+	defer md.mu.Unlock()
+	md.Chunks.Add(off, n)
+}
+
+func (md *Metadata) ReadAt(p []byte, pos int64) (int, error) {
+	return md.f.ReadAt(p, pos)
+}
+
+func (md *Metadata) WriteAt(data []byte, pos int64) (int, error) {
+	return md.f.WriteAt(data, pos)
+}
+
+func (md *Metadata) Preload() bool {
+	md.mu.Lock()
+	defer md.mu.Unlock()
+	if md.preload {
+		return true
+	}
+	md.preload = true
+	return false
+}
+
+func (md *Metadata) UnlockPreload() {
+	md.mu.Lock()
+	defer md.mu.Unlock()
+	md.preload = false
+}