Replace mount's per-file cache by a global LRU cache

internal/fuse/fuse_test.go

@@ -20,6 +20,48 @@ import (
 	rtest "github.com/restic/restic/internal/test"
 )
 
+func TestCache(t *testing.T) {
+	var id1, id2, id3 restic.ID
+	id1[0] = 1
+	id2[0] = 2
+	id3[0] = 3
+
+	const (
+		kiB       = 1 << 10
+		cacheSize = 64*kiB + 3*cacheOverhead
+	)
+
+	c := newBlobCache(cacheSize)
+
+	addAndCheck := func(id restic.ID, exp []byte) {
+		c.add(id, exp)
+		blob, ok := c.get(id)
+		rtest.Assert(t, ok, "blob %v added but not found in cache", id)
+		rtest.Equals(t, &exp[0], &blob[0])
+		rtest.Equals(t, exp, blob)
+	}
+
+	addAndCheck(id1, make([]byte, 32*kiB))
+	addAndCheck(id2, make([]byte, 30*kiB))
+	addAndCheck(id3, make([]byte, 10*kiB))
+
+	_, ok := c.get(id2)
+	rtest.Assert(t, ok, "blob %v not present", id2)
+	_, ok = c.get(id1)
+	rtest.Assert(t, !ok, "blob %v present, but should have been evicted", id1)
+
+	c.add(id1, make([]byte, 1+c.size))
+	_, ok = c.get(id1)
+	rtest.Assert(t, !ok, "blob %v too large but still added to cache")
+
+	c.c.Remove(id1)
+	c.c.Remove(id3)
+	c.c.Remove(id2)
+
+	rtest.Equals(t, cacheSize, c.size)
+	rtest.Equals(t, cacheSize, c.free)
+}
+
 func testRead(t testing.TB, f *file, offset, length int, data []byte) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
@@ -114,10 +156,7 @@ func TestFuseFile(t *testing.T) {
 		Size:    filesize,
 		Content: content,
 	}
-	root := &Root{
-		blobSizeCache: NewBlobSizeCache(context.TODO(), repo.Index()),
-		repo:          repo,
-	}
+	root := NewRoot(context.TODO(), repo, Config{})
 
 	t.Logf("blob cache has %d entries", len(root.blobSizeCache.m))
 
@@ -163,11 +202,10 @@ func testTopUidGid(t *testing.T, cfg Config, repo restic.Repository, uid, gid ui
 	t.Helper()
 
 	ctx := context.Background()
-	root, err := NewRoot(ctx, repo, cfg)
-	rtest.OK(t, err)
+	root := NewRoot(ctx, repo, cfg)
 
 	var attr fuse.Attr
-	err = root.Attr(ctx, &attr)
+	err := root.Attr(ctx, &attr)
 	rtest.OK(t, err)
 	rtest.Equals(t, uid, attr.Uid)
 	rtest.Equals(t, gid, attr.Gid)