Merge pull request #2760 from greatroar/backend-benchmark

Fix backend benchmarks + a micro-optimization

internal/backend/test/benchmarks.go

@@ -48,17 +48,17 @@ func (s *Suite) BenchmarkLoadFile(t *testing.B) {
 			n, ierr = io.ReadFull(rd, buf)
 			return ierr
 		})
-		if err != nil {
+
+		t.StopTimer()
+		switch {
+		case err != nil:
 			t.Fatal(err)
-		}
+		case n != length:
-
-		if n != length {
 			t.Fatalf("wrong number of bytes read: want %v, got %v", length, n)
-		}
+		case !bytes.Equal(data, buf):
-
-		if !bytes.Equal(data, buf) {
 			t.Fatalf("wrong bytes returned")
 		}
+		t.StartTimer()
 	}
 }
 
@@ -85,18 +85,17 @@ func (s *Suite) BenchmarkLoadPartialFile(t *testing.B) {
 			n, ierr = io.ReadFull(rd, buf)
 			return ierr
 		})
-		if err != nil {
+
+		t.StopTimer()
+		switch {
+		case err != nil:
 			t.Fatal(err)
-		}
+		case n != testLength:
-
-		if n != testLength {
 			t.Fatalf("wrong number of bytes read: want %v, got %v", testLength, n)
-		}
+		case !bytes.Equal(data[:testLength], buf):
-
-		if !bytes.Equal(data[:testLength], buf) {
 			t.Fatalf("wrong bytes returned")
 		}
-
+		t.StartTimer()
 	}
 }
 
@@ -124,17 +123,17 @@ func (s *Suite) BenchmarkLoadPartialFileOffset(t *testing.B) {
 			n, ierr = io.ReadFull(rd, buf)
 			return ierr
 		})
-		if err != nil {
+
+		t.StopTimer()
+		switch {
+		case err != nil:
 			t.Fatal(err)
-		}
+		case n != testLength:
-
-		if n != testLength {
 			t.Fatalf("wrong number of bytes read: want %v, got %v", testLength, n)
-		}
+		case !bytes.Equal(data[testOffset:testOffset+testLength], buf):
-
-		if !bytes.Equal(data[testOffset:testOffset+testLength], buf) {
 			t.Fatalf("wrong bytes returned")
 		}
+		t.StartTimer()
 
 	}
 }

internal/backend/utils.go

@@ -32,19 +32,14 @@ func LoadAll(ctx context.Context, buf []byte, be restic.Backend, h restic.Handle
 
 // LimitedReadCloser wraps io.LimitedReader and exposes the Close() method.
 type LimitedReadCloser struct {
-	io.ReadCloser
+	io.Closer
-	io.Reader
+	io.LimitedReader
 }
 
-// Read reads data from the limited reader.
+// LimitReadCloser returns a new reader wraps r in an io.LimitedReader, but also
-func (l *LimitedReadCloser) Read(p []byte) (int, error) {
-	return l.Reader.Read(p)
-}
-
-// LimitReadCloser returns a new reader wraps r in an io.LimitReader, but also
 // exposes the Close() method.
 func LimitReadCloser(r io.ReadCloser, n int64) *LimitedReadCloser {
-	return &LimitedReadCloser{ReadCloser: r, Reader: io.LimitReader(r, n)}
+	return &LimitedReadCloser{Closer: r, LimitedReader: io.LimitedReader{R: r, N: n}}
 }
 
 // DefaultLoad implements Backend.Load using lower-level openReader func