From a37ed45534dd97bb11078fe6fb39b120a582b819 Mon Sep 17 00:00:00 2001
From: Alexander Neumann <alexander@bumpern.de>
Date: Sun, 7 Feb 2016 23:48:03 +0100
Subject: [PATCH 1/2] Add test for LoadAll with too large buffer

LoadAll() should not pass on io.ErrUnexpectedEOF, since the occurrence
of this error is normal.
---
 backend/test/tests.go | 11 +++++++++
 backend/utils_test.go | 52 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 63 insertions(+)

diff --git a/backend/test/tests.go b/backend/test/tests.go
index e71412381..e178d39d8 100644
--- a/backend/test/tests.go
+++ b/backend/test/tests.go
@@ -245,6 +245,17 @@ func TestLoad(t testing.TB) {
 		}
 	}
 
+	// load with a too-large buffer, this should return io.ErrUnexpectedEOF
+	buf := make([]byte, length+100)
+	n, err := b.Load(handle, buf, 0)
+	if n != length {
+		t.Errorf("wrong length for larger buffer returned, want %d, got %d", length, n)
+	}
+
+	if err != io.ErrUnexpectedEOF {
+		t.Errorf("wrong error returned for larger buffer: want io.ErrUnexpectedEOF, got %#v", err)
+	}
+
 	OK(t, b.Remove(backend.Data, id.String()))
 }
 
diff --git a/backend/utils_test.go b/backend/utils_test.go
index 98a0106ef..00d7f5cab 100644
--- a/backend/utils_test.go
+++ b/backend/utils_test.go
@@ -37,3 +37,55 @@ func TestLoadAll(t *testing.T) {
 		}
 	}
 }
+
+func TestLoadSmallBuffer(t *testing.T) {
+	b := mem.New()
+
+	for i := 0; i < 20; i++ {
+		data := Random(23+i, rand.Intn(MiB)+500*KiB)
+
+		id := backend.Hash(data)
+		err := b.Save(backend.Handle{Name: id.String(), Type: backend.Data}, data)
+		OK(t, err)
+
+		buf := make([]byte, len(data)-23)
+		buf, err = backend.LoadAll(b, backend.Handle{Type: backend.Data, Name: id.String()}, buf)
+		OK(t, err)
+
+		if len(buf) != len(data) {
+			t.Errorf("length of returned buffer does not match, want %d, got %d", len(data), len(buf))
+			continue
+		}
+
+		if !bytes.Equal(buf, data) {
+			t.Errorf("wrong data returned")
+			continue
+		}
+	}
+}
+
+func TestLoadLargeBuffer(t *testing.T) {
+	b := mem.New()
+
+	for i := 0; i < 20; i++ {
+		data := Random(23+i, rand.Intn(MiB)+500*KiB)
+
+		id := backend.Hash(data)
+		err := b.Save(backend.Handle{Name: id.String(), Type: backend.Data}, data)
+		OK(t, err)
+
+		buf := make([]byte, len(data)+100)
+		buf, err = backend.LoadAll(b, backend.Handle{Type: backend.Data, Name: id.String()}, buf)
+		OK(t, err)
+
+		if len(buf) != len(data) {
+			t.Errorf("length of returned buffer does not match, want %d, got %d", len(data), len(buf))
+			continue
+		}
+
+		if !bytes.Equal(buf, data) {
+			t.Errorf("wrong data returned")
+			continue
+		}
+	}
+}

From e9a21c1dc62b62d14abb2f1435f0a5ecf361e2a0 Mon Sep 17 00:00:00 2001
From: Alexander Neumann <alexander@bumpern.de>
Date: Thu, 4 Feb 2016 19:37:33 +0100
Subject: [PATCH 2/2] backend.LoadAll: return nil on expected error

The current code returns io.ErrUnexpectedEOF, but it is the normal,
expected behaviour of the function LoadAll() to load until the item is
completely loaded. Therefore, the io.ErrUnexpectedEOF is not returned to
the caller.
---
 backend/utils.go | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/backend/utils.go b/backend/utils.go
index c40d35e12..e1c36236b 100644
--- a/backend/utils.go
+++ b/backend/utils.go
@@ -1,7 +1,11 @@
 package backend
 
+import "io"
+
 // LoadAll reads all data stored in the backend for the handle. The buffer buf
-// is resized to accomodate all data in the blob.
+// is resized to accomodate all data in the blob. Errors returned by be.Load()
+// are passed on, except io.ErrUnexpectedEOF is silenced and nil returned
+// instead, since it means this function is working properly.
 func LoadAll(be Backend, h Handle, buf []byte) ([]byte, error) {
 	fi, err := be.Stat(h)
 	if err != nil {
@@ -13,6 +17,9 @@ func LoadAll(be Backend, h Handle, buf []byte) ([]byte, error) {
 	}
 
 	n, err := be.Load(h, buf, 0)
+	if err == io.ErrUnexpectedEOF {
+		err = nil
+	}
 	buf = buf[:n]
 	return buf, err
 }