From f15a3f89666ab99d76712d66672bbc897bdf01ab Mon Sep 17 00:00:00 2001
From: Ashwanth Goli <iamashwanth@gmail.com>
Date: Tue, 15 Oct 2024 11:32:43 +0530
Subject: [PATCH 1/7] Include content length in the response of Get and
 GetRange

Signed-off-by: Ashwanth Goli <iamashwanth@gmail.com>
---
 objstore.go                        | 10 ++++++++++
 providers/azure/azure.go           |  2 +-
 providers/bos/bos.go               |  2 +-
 providers/cos/cos.go               | 12 +-----------
 providers/filesystem/filesystem.go | 13 ++++++++++---
 providers/gcs/gcs.go               | 14 ++++++++++++--
 providers/obs/obs.go               |  2 +-
 providers/oci/oci.go               |  4 ++--
 providers/s3/s3.go                 |  5 ++++-
 9 files changed, 42 insertions(+), 22 deletions(-)

diff --git a/objstore.go b/objstore.go
index bfee7503..dcb65e1d 100644
--- a/objstore.go
+++ b/objstore.go
@@ -829,3 +829,13 @@ func (t *timingReaderWriterTo) WriteTo(w io.Writer) (n int64, err error) {
 	t.timingReader.updateMetrics(int(n), err)
 	return n, err
 }
+
+type ObjectSizerReadCloser struct {
+	io.ReadCloser
+	Size int64
+}
+
+// ObjectSize implement ObjectSizer.
+func (o ObjectSizerReadCloser) ObjectSize() (int64, error) {
+	return o.Size, nil
+}
diff --git a/providers/azure/azure.go b/providers/azure/azure.go
index c2f3adb5..957ccdd6 100644
--- a/providers/azure/azure.go
+++ b/providers/azure/azure.go
@@ -273,7 +273,7 @@ func (b *Bucket) getBlobReader(ctx context.Context, name string, httpRange blob.
 		return nil, errors.Wrapf(err, "cannot download blob, address: %s", blobClient.URL())
 	}
 	retryOpts := azblob.RetryReaderOptions{MaxRetries: int32(b.readerMaxRetries)}
-	return resp.NewRetryReader(ctx, &retryOpts), nil
+	return objstore.ObjectSizerReadCloser{ReadCloser: resp.NewRetryReader(ctx, &retryOpts), Size: *resp.ContentLength}, nil
 }
 
 // Get returns a reader for the given object name.
diff --git a/providers/bos/bos.go b/providers/bos/bos.go
index 74f9688e..6a111fe2 100644
--- a/providers/bos/bos.go
+++ b/providers/bos/bos.go
@@ -308,7 +308,7 @@ func (b *Bucket) getRange(_ context.Context, bucketName, objectKey string, off,
 		return nil, err
 	}
 
-	return obj.Body, nil
+	return objstore.ObjectSizerReadCloser{ReadCloser: obj.Body, Size: obj.ContentLength}, err
 }
 
 func configFromEnv() Config {
diff --git a/providers/cos/cos.go b/providers/cos/cos.go
index a8b853e3..2c1c07fe 100644
--- a/providers/cos/cos.go
+++ b/providers/cos/cos.go
@@ -320,20 +320,10 @@ func (b *Bucket) getRange(ctx context.Context, name string, off, length int64) (
 		return nil, err
 	}
 	// Add size info into reader to pass it to Upload function.
-	r := objectSizerReadCloser{ReadCloser: resp.Body, size: resp.ContentLength}
+	r := objstore.ObjectSizerReadCloser{ReadCloser: resp.Body, Size: resp.ContentLength}
 	return r, nil
 }
 
-type objectSizerReadCloser struct {
-	io.ReadCloser
-	size int64
-}
-
-// ObjectSize implement objstore.ObjectSizer.
-func (o objectSizerReadCloser) ObjectSize() (int64, error) {
-	return o.size, nil
-}
-
 // Get returns a reader for the given object name.
 func (b *Bucket) Get(ctx context.Context, name string) (io.ReadCloser, error) {
 	return b.getRange(ctx, name, 0, -1)
diff --git a/providers/filesystem/filesystem.go b/providers/filesystem/filesystem.go
index 21c70485..be49c5f3 100644
--- a/providers/filesystem/filesystem.go
+++ b/providers/filesystem/filesystem.go
@@ -150,8 +150,12 @@ func (b *Bucket) GetRange(ctx context.Context, name string, off, length int64) (
 		return nil, errors.New("object name is empty")
 	}
 
-	file := filepath.Join(b.rootDir, name)
-	if _, err := os.Stat(file); err != nil {
+	var (
+		file = filepath.Join(b.rootDir, name)
+		stat os.FileInfo
+		err  error
+	)
+	if stat, err = os.Stat(file); err != nil {
 		return nil, errors.Wrapf(err, "stat %s", file)
 	}
 
@@ -171,7 +175,10 @@ func (b *Bucket) GetRange(ctx context.Context, name string, off, length int64) (
 		return f, nil
 	}
 
-	return &rangeReaderCloser{Reader: io.LimitReader(f, length), f: f}, nil
+	return objstore.ObjectSizerReadCloser{
+		ReadCloser: &rangeReaderCloser{Reader: io.LimitReader(f, length),
+			f: f,
+		}, Size: stat.Size()}, nil
 }
 
 // Exists checks if the given directory exists in memory.
diff --git a/providers/gcs/gcs.go b/providers/gcs/gcs.go
index b5dae200..89582774 100644
--- a/providers/gcs/gcs.go
+++ b/providers/gcs/gcs.go
@@ -226,12 +226,22 @@ func (b *Bucket) Iter(ctx context.Context, dir string, f func(string) error, opt
 
 // Get returns a reader for the given object name.
 func (b *Bucket) Get(ctx context.Context, name string) (io.ReadCloser, error) {
-	return b.bkt.Object(name).NewReader(ctx)
+	r, err := b.bkt.Object(name).NewReader(ctx)
+	if err != nil {
+		return r, err
+	}
+
+	return objstore.ObjectSizerReadCloser{ReadCloser: r, Size: r.Attrs.Size}, nil
 }
 
 // GetRange returns a new range reader for the given object name and range.
 func (b *Bucket) GetRange(ctx context.Context, name string, off, length int64) (io.ReadCloser, error) {
-	return b.bkt.Object(name).NewRangeReader(ctx, off, length)
+	r, err := b.bkt.Object(name).NewRangeReader(ctx, off, length)
+	if err != nil {
+		return r, err
+	}
+
+	return objstore.ObjectSizerReadCloser{ReadCloser: r, Size: r.Attrs.Size}, nil
 }
 
 // Attributes returns information about the specified object.
diff --git a/providers/obs/obs.go b/providers/obs/obs.go
index 7de70633..ec513f90 100644
--- a/providers/obs/obs.go
+++ b/providers/obs/obs.go
@@ -299,7 +299,7 @@ func (b *Bucket) getRange(_ context.Context, name string, off, length int64) (io
 	if err != nil {
 		return nil, errors.Wrap(err, "failed to get object")
 	}
-	return output.Body, nil
+	return objstore.ObjectSizerReadCloser{ReadCloser: output.Body, Size: output.ContentLength}, nil
 }
 
 // Exists checks if the given object exists in the bucket.
diff --git a/providers/oci/oci.go b/providers/oci/oci.go
index e2f9e98b..b5c3bed1 100644
--- a/providers/oci/oci.go
+++ b/providers/oci/oci.go
@@ -134,7 +134,7 @@ func (b *Bucket) Get(ctx context.Context, name string) (io.ReadCloser, error) {
 	if err != nil {
 		return nil, err
 	}
-	return response.Content, nil
+	return objstore.ObjectSizerReadCloser{ReadCloser: response.Content, Size: *response.ContentLength}, nil
 }
 
 // GetRange returns a new range reader for the given object name and range.
@@ -164,7 +164,7 @@ func (b *Bucket) GetRange(ctx context.Context, name string, offset, length int64
 	if err != nil {
 		return nil, err
 	}
-	return response.Content, nil
+	return objstore.ObjectSizerReadCloser{ReadCloser: response.Content, Size: *response.ContentLength}, nil
 }
 
 // Upload the contents of the reader as an object into the bucket.
diff --git a/providers/s3/s3.go b/providers/s3/s3.go
index 2f0447a7..ebed16ee 100644
--- a/providers/s3/s3.go
+++ b/providers/s3/s3.go
@@ -452,7 +452,10 @@ func (b *Bucket) getRange(ctx context.Context, name string, off, length int64) (
 		return nil, err
 	}
 
-	return r, nil
+	return objstore.ObjectSizerReadCloser{
+		ReadCloser: r,
+		Size:       0,
+	}, nil
 }
 
 // Get returns a reader for the given object name.

From 76887a7c572dfab8e65561781724045d14f37bc1 Mon Sep 17 00:00:00 2001
From: Ashwanth Goli <iamashwanth@gmail.com>
Date: Tue, 8 Oct 2024 19:42:09 +0530
Subject: [PATCH 2/7] add for oss

Signed-off-by: Ashwanth Goli <iamashwanth@gmail.com>
---
 providers/oss/oss.go | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/providers/oss/oss.go b/providers/oss/oss.go
index 0a4cc76e..1f59d7f3 100644
--- a/providers/oss/oss.go
+++ b/providers/oss/oss.go
@@ -16,6 +16,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/aliyun/aliyun-oss-go-sdk/oss"
 	alioss "github.com/aliyun/aliyun-oss-go-sdk/oss"
 	"github.com/go-kit/log"
 	"github.com/pkg/errors"
@@ -342,12 +343,17 @@ func (b *Bucket) getRange(_ context.Context, name string, off, length int64) (io
 		opts = append(opts, opt)
 	}
 
-	resp, err := b.bucket.GetObject(name, opts...)
+	resp, err := b.bucket.DoGetObject(&oss.GetObjectRequest{ObjectKey: name}, opts)
 	if err != nil {
 		return nil, err
 	}
 
-	return resp, nil
+	size, err := clientutil.ParseContentLength(resp.Response.Headers)
+	if err == nil {
+		return objstore.ObjectSizerReadCloser{ReadCloser: resp.Response, Size: size}, nil
+	}
+
+	return resp.Response, nil
 }
 
 // Get returns a reader for the given object name.

From 7fdd46598d15d4eaa33cf057e345241b9dd205f2 Mon Sep 17 00:00:00 2001
From: Ashwanth Goli <iamashwanth@gmail.com>
Date: Tue, 8 Oct 2024 19:49:01 +0530
Subject: [PATCH 3/7] add changelog

Signed-off-by: Ashwanth Goli <iamashwanth@gmail.com>
---
 CHANGELOG.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 12375cbf..4686a470 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@ We use *breaking :warning:* to mark changes that are not backward compatible (re
 
 ## Unreleased
 - [#38](https://github.com/thanos-io/objstore/pull/38) GCS: Upgrade cloud.google.com/go/storage version to `v1.43.0`.
+- [#145](https://github.com/thanos-io/objstore/pull/145) Include content length in the response of Get and GetRange.
 
 ### Fixed
 - [#117](https://github.com/thanos-io/objstore/pull/117) Metrics: Fix `objstore_bucket_operation_failures_total` incorrectly incremented if context is cancelled while reading object contents.

From 37b701c09aaea0648bfaf6fb493008ab33657d17 Mon Sep 17 00:00:00 2001
From: Ashwanth Goli <iamashwanth@gmail.com>
Date: Wed, 9 Oct 2024 18:38:45 +0530
Subject: [PATCH 4/7] update getRange for fs

Signed-off-by: Ashwanth Goli <iamashwanth@gmail.com>
---
 providers/filesystem/filesystem.go | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/providers/filesystem/filesystem.go b/providers/filesystem/filesystem.go
index be49c5f3..423abb90 100644
--- a/providers/filesystem/filesystem.go
+++ b/providers/filesystem/filesystem.go
@@ -164,21 +164,29 @@ func (b *Bucket) GetRange(ctx context.Context, name string, off, length int64) (
 		return nil, err
 	}
 
+	var newOffset int64
 	if off > 0 {
-		_, err := f.Seek(off, 0)
+		newOffset, err = f.Seek(off, 0)
 		if err != nil {
 			return nil, errors.Wrapf(err, "seek %v", off)
 		}
 	}
 
+	size := stat.Size() - newOffset
 	if length == -1 {
-		return f, nil
+		return objstore.ObjectSizerReadCloser{
+			ReadCloser: f,
+			Size:       size,
+		}, nil
 	}
 
 	return objstore.ObjectSizerReadCloser{
-		ReadCloser: &rangeReaderCloser{Reader: io.LimitReader(f, length),
-			f: f,
-		}, Size: stat.Size()}, nil
+		ReadCloser: &rangeReaderCloser{
+			Reader: io.LimitReader(f, length),
+			f:      f,
+		},
+		Size: min(length, size),
+	}, nil
 }
 
 // Exists checks if the given directory exists in memory.

From ddca4de27326b4fb5958eb8ec097edc71763c545 Mon Sep 17 00:00:00 2001
From: Ashwanth Goli <iamashwanth@gmail.com>
Date: Tue, 15 Oct 2024 11:33:50 +0530
Subject: [PATCH 5/7] add acceptance test + refactor

Signed-off-by: Ashwanth Goli <iamashwanth@gmail.com>
---
 objstore.go                        |  4 ++--
 providers/azure/azure.go           |  8 +++++++-
 providers/bos/bos.go               |  7 ++++++-
 providers/cos/cos.go               |  8 ++++++--
 providers/filesystem/filesystem.go |  8 ++++++--
 providers/gcs/gcs.go               | 15 +++++++++++++--
 providers/obs/obs.go               |  7 ++++++-
 providers/oci/oci.go               | 13 +++++++++++--
 providers/oss/oss.go               |  7 ++++++-
 providers/s3/s3.go                 |  9 ++++++++-
 providers/swift/swift.go           |  6 +++++-
 testing.go                         | 20 ++++++++++++++++++++
 12 files changed, 96 insertions(+), 16 deletions(-)

diff --git a/objstore.go b/objstore.go
index dcb65e1d..116538ca 100644
--- a/objstore.go
+++ b/objstore.go
@@ -832,10 +832,10 @@ func (t *timingReaderWriterTo) WriteTo(w io.Writer) (n int64, err error) {
 
 type ObjectSizerReadCloser struct {
 	io.ReadCloser
-	Size int64
+	Size func() (int64, error)
 }
 
 // ObjectSize implement ObjectSizer.
 func (o ObjectSizerReadCloser) ObjectSize() (int64, error) {
-	return o.Size, nil
+	return o.Size()
 }
diff --git a/providers/azure/azure.go b/providers/azure/azure.go
index 957ccdd6..9a4e8518 100644
--- a/providers/azure/azure.go
+++ b/providers/azure/azure.go
@@ -273,7 +273,13 @@ func (b *Bucket) getBlobReader(ctx context.Context, name string, httpRange blob.
 		return nil, errors.Wrapf(err, "cannot download blob, address: %s", blobClient.URL())
 	}
 	retryOpts := azblob.RetryReaderOptions{MaxRetries: int32(b.readerMaxRetries)}
-	return objstore.ObjectSizerReadCloser{ReadCloser: resp.NewRetryReader(ctx, &retryOpts), Size: *resp.ContentLength}, nil
+
+	return objstore.ObjectSizerReadCloser{
+		ReadCloser: resp.NewRetryReader(ctx, &retryOpts),
+		Size: func() (int64, error) {
+			return *resp.ContentLength, nil
+		},
+	}, nil
 }
 
 // Get returns a reader for the given object name.
diff --git a/providers/bos/bos.go b/providers/bos/bos.go
index 6a111fe2..1f81e920 100644
--- a/providers/bos/bos.go
+++ b/providers/bos/bos.go
@@ -308,7 +308,12 @@ func (b *Bucket) getRange(_ context.Context, bucketName, objectKey string, off,
 		return nil, err
 	}
 
-	return objstore.ObjectSizerReadCloser{ReadCloser: obj.Body, Size: obj.ContentLength}, err
+	return objstore.ObjectSizerReadCloser{
+		ReadCloser: obj.Body,
+		Size: func() (int64, error) {
+			return obj.ContentLength, nil
+		},
+	}, err
 }
 
 func configFromEnv() Config {
diff --git a/providers/cos/cos.go b/providers/cos/cos.go
index 2c1c07fe..f88a8e76 100644
--- a/providers/cos/cos.go
+++ b/providers/cos/cos.go
@@ -320,8 +320,12 @@ func (b *Bucket) getRange(ctx context.Context, name string, off, length int64) (
 		return nil, err
 	}
 	// Add size info into reader to pass it to Upload function.
-	r := objstore.ObjectSizerReadCloser{ReadCloser: resp.Body, Size: resp.ContentLength}
-	return r, nil
+	return objstore.ObjectSizerReadCloser{
+		ReadCloser: resp.Body,
+		Size: func() (int64, error) {
+			return resp.ContentLength, nil
+		},
+	}, nil
 }
 
 // Get returns a reader for the given object name.
diff --git a/providers/filesystem/filesystem.go b/providers/filesystem/filesystem.go
index 423abb90..2ed42ee8 100644
--- a/providers/filesystem/filesystem.go
+++ b/providers/filesystem/filesystem.go
@@ -176,7 +176,9 @@ func (b *Bucket) GetRange(ctx context.Context, name string, off, length int64) (
 	if length == -1 {
 		return objstore.ObjectSizerReadCloser{
 			ReadCloser: f,
-			Size:       size,
+			Size: func() (int64, error) {
+				return size, nil
+			},
 		}, nil
 	}
 
@@ -185,7 +187,9 @@ func (b *Bucket) GetRange(ctx context.Context, name string, off, length int64) (
 			Reader: io.LimitReader(f, length),
 			f:      f,
 		},
-		Size: min(length, size),
+		Size: func() (int64, error) {
+			return min(length, size), nil
+		},
 	}, nil
 }
 
diff --git a/providers/gcs/gcs.go b/providers/gcs/gcs.go
index 89582774..e022b14f 100644
--- a/providers/gcs/gcs.go
+++ b/providers/gcs/gcs.go
@@ -231,7 +231,12 @@ func (b *Bucket) Get(ctx context.Context, name string) (io.ReadCloser, error) {
 		return r, err
 	}
 
-	return objstore.ObjectSizerReadCloser{ReadCloser: r, Size: r.Attrs.Size}, nil
+	return objstore.ObjectSizerReadCloser{
+		ReadCloser: r,
+		Size: func() (int64, error) {
+			return r.Attrs.Size, nil
+		},
+	}, nil
 }
 
 // GetRange returns a new range reader for the given object name and range.
@@ -241,7 +246,13 @@ func (b *Bucket) GetRange(ctx context.Context, name string, off, length int64) (
 		return r, err
 	}
 
-	return objstore.ObjectSizerReadCloser{ReadCloser: r, Size: r.Attrs.Size}, nil
+	sz := r.Remain()
+	return objstore.ObjectSizerReadCloser{
+		ReadCloser: r,
+		Size: func() (int64, error) {
+			return sz, nil
+		},
+	}, nil
 }
 
 // Attributes returns information about the specified object.
diff --git a/providers/obs/obs.go b/providers/obs/obs.go
index ec513f90..cb450365 100644
--- a/providers/obs/obs.go
+++ b/providers/obs/obs.go
@@ -299,7 +299,12 @@ func (b *Bucket) getRange(_ context.Context, name string, off, length int64) (io
 	if err != nil {
 		return nil, errors.Wrap(err, "failed to get object")
 	}
-	return objstore.ObjectSizerReadCloser{ReadCloser: output.Body, Size: output.ContentLength}, nil
+	return objstore.ObjectSizerReadCloser{
+		ReadCloser: output.Body,
+		Size: func() (int64, error) {
+			return output.ContentLength, nil
+		},
+	}, nil
 }
 
 // Exists checks if the given object exists in the bucket.
diff --git a/providers/oci/oci.go b/providers/oci/oci.go
index b5c3bed1..3bdf80f3 100644
--- a/providers/oci/oci.go
+++ b/providers/oci/oci.go
@@ -134,7 +134,12 @@ func (b *Bucket) Get(ctx context.Context, name string) (io.ReadCloser, error) {
 	if err != nil {
 		return nil, err
 	}
-	return objstore.ObjectSizerReadCloser{ReadCloser: response.Content, Size: *response.ContentLength}, nil
+	return objstore.ObjectSizerReadCloser{
+		ReadCloser: response.Content,
+		Size: func() (int64, error) {
+			return *response.ContentLength, nil
+		},
+	}, nil
 }
 
 // GetRange returns a new range reader for the given object name and range.
@@ -164,7 +169,11 @@ func (b *Bucket) GetRange(ctx context.Context, name string, offset, length int64
 	if err != nil {
 		return nil, err
 	}
-	return objstore.ObjectSizerReadCloser{ReadCloser: response.Content, Size: *response.ContentLength}, nil
+	return objstore.ObjectSizerReadCloser{ReadCloser: response.Content,
+		Size: func() (int64, error) {
+			return *response.ContentLength, nil
+		},
+	}, nil
 }
 
 // Upload the contents of the reader as an object into the bucket.
diff --git a/providers/oss/oss.go b/providers/oss/oss.go
index 1f59d7f3..d6e1bbf5 100644
--- a/providers/oss/oss.go
+++ b/providers/oss/oss.go
@@ -350,7 +350,12 @@ func (b *Bucket) getRange(_ context.Context, name string, off, length int64) (io
 
 	size, err := clientutil.ParseContentLength(resp.Response.Headers)
 	if err == nil {
-		return objstore.ObjectSizerReadCloser{ReadCloser: resp.Response, Size: size}, nil
+		return objstore.ObjectSizerReadCloser{
+			ReadCloser: resp.Response,
+			Size: func() (int64, error) {
+				return size, nil
+			},
+		}, nil
 	}
 
 	return resp.Response, nil
diff --git a/providers/s3/s3.go b/providers/s3/s3.go
index ebed16ee..eac8191a 100644
--- a/providers/s3/s3.go
+++ b/providers/s3/s3.go
@@ -454,7 +454,14 @@ func (b *Bucket) getRange(ctx context.Context, name string, off, length int64) (
 
 	return objstore.ObjectSizerReadCloser{
 		ReadCloser: r,
-		Size:       0,
+		Size: func() (int64, error) {
+			stat, err := r.Stat()
+			if err != nil {
+				return 0, err
+			}
+
+			return stat.Size, nil
+		},
 	}, nil
 }
 
diff --git a/providers/swift/swift.go b/providers/swift/swift.go
index 682c494c..44fa6ed0 100644
--- a/providers/swift/swift.go
+++ b/providers/swift/swift.go
@@ -262,7 +262,11 @@ func (c *Container) get(name string, headers swift.Headers, checkHash bool) (io.
 	if err != nil {
 		return nil, errors.Wrap(err, "open object")
 	}
-	return file, err
+
+	return objstore.ObjectSizerReadCloser{
+		ReadCloser: file,
+		Size:       file.Length,
+	}, nil
 }
 
 // Get returns a reader for the given object name.
diff --git a/testing.go b/testing.go
index b8e3744c..28cbd658 100644
--- a/testing.go
+++ b/testing.go
@@ -106,6 +106,11 @@ func AcceptanceTest(t *testing.T, bkt Bucket) {
 	rc1, err := bkt.Get(ctx, "id1/obj_1.some")
 	testutil.Ok(t, err)
 	defer func() { testutil.Ok(t, rc1.Close()) }()
+
+	sz, err := TryToGetSize(rc1)
+	testutil.Ok(t, err)
+	testutil.Equals(t, int64(11), sz, "expected size to be equal to 11")
+
 	content, err := io.ReadAll(rc1)
 	testutil.Ok(t, err)
 	testutil.Equals(t, "@test-data@", string(content))
@@ -118,6 +123,11 @@ func AcceptanceTest(t *testing.T, bkt Bucket) {
 	rc2, err := bkt.GetRange(ctx, "id1/obj_1.some", 1, 3)
 	testutil.Ok(t, err)
 	defer func() { testutil.Ok(t, rc2.Close()) }()
+
+	sz, err = TryToGetSize(rc2)
+	testutil.Ok(t, err)
+	testutil.Equals(t, int64(3), sz, "expected size to be equal to 3")
+
 	content, err = io.ReadAll(rc2)
 	testutil.Ok(t, err)
 	testutil.Equals(t, "tes", string(content))
@@ -126,6 +136,11 @@ func AcceptanceTest(t *testing.T, bkt Bucket) {
 	rcUnspecifiedLen, err := bkt.GetRange(ctx, "id1/obj_1.some", 1, -1)
 	testutil.Ok(t, err)
 	defer func() { testutil.Ok(t, rcUnspecifiedLen.Close()) }()
+
+	sz, err = TryToGetSize(rcUnspecifiedLen)
+	testutil.Ok(t, err)
+	testutil.Equals(t, int64(10), sz, "expected size to be equal to 10")
+
 	content, err = io.ReadAll(rcUnspecifiedLen)
 	testutil.Ok(t, err)
 	testutil.Equals(t, "test-data@", string(content))
@@ -141,6 +156,11 @@ func AcceptanceTest(t *testing.T, bkt Bucket) {
 	rcLength, err := bkt.GetRange(ctx, "id1/obj_1.some", 3, 9999)
 	testutil.Ok(t, err)
 	defer func() { testutil.Ok(t, rcLength.Close()) }()
+
+	sz, err = TryToGetSize(rcLength)
+	testutil.Ok(t, err)
+	testutil.Equals(t, int64(8), sz, "expected size to be equal to 8")
+
 	content, err = io.ReadAll(rcLength)
 	testutil.Ok(t, err)
 	testutil.Equals(t, "st-data@", string(content))

From 2947125233e6b3edace706149b6862e911458058 Mon Sep 17 00:00:00 2001
From: Ashwanth Goli <iamashwanth@gmail.com>
Date: Thu, 10 Oct 2024 12:07:04 +0530
Subject: [PATCH 6/7] add size for inmem

Signed-off-by: Ashwanth Goli <iamashwanth@gmail.com>
---
 inmem.go | 32 +++++++++++++++++++++++++++-----
 1 file changed, 27 insertions(+), 5 deletions(-)

diff --git a/inmem.go b/inmem.go
index 3f6f35e9..ed256c9c 100644
--- a/inmem.go
+++ b/inmem.go
@@ -119,7 +119,12 @@ func (b *InMemBucket) Get(_ context.Context, name string) (io.ReadCloser, error)
 		return nil, errNotFound
 	}
 
-	return io.NopCloser(bytes.NewReader(file)), nil
+	return ObjectSizerReadCloser{
+		ReadCloser: io.NopCloser(bytes.NewReader(file)),
+		Size: func() (int64, error) {
+			return int64(len(file)), nil
+		},
+	}, nil
 }
 
 // GetRange returns a new range reader for the given object name and range.
@@ -136,15 +141,27 @@ func (b *InMemBucket) GetRange(_ context.Context, name string, off, length int64
 	}
 
 	if int64(len(file)) < off {
-		return io.NopCloser(bytes.NewReader(nil)), nil
+		return ObjectSizerReadCloser{
+			ReadCloser: io.NopCloser(bytes.NewReader(nil)),
+			Size:       func() (int64, error) { return 0, nil },
+		}, nil
 	}
 
 	if length == -1 {
-		return io.NopCloser(bytes.NewReader(file[off:])), nil
+		return ObjectSizerReadCloser{
+			ReadCloser: io.NopCloser(bytes.NewReader(file[off:])),
+			Size: func() (int64, error) {
+				return int64(len(file[off:])), nil
+			},
+		}, nil
 	}
 
 	if length <= 0 {
-		return io.NopCloser(bytes.NewReader(nil)), errors.New("length cannot be smaller or equal 0")
+		// wrap with ObjectSizerReadCloser to return 0 size.
+		return ObjectSizerReadCloser{
+			ReadCloser: io.NopCloser(bytes.NewReader(nil)),
+			Size:       func() (int64, error) { return 0, nil },
+		}, errors.New("length cannot be smaller or equal 0")
 	}
 
 	if int64(len(file)) <= off+length {
@@ -152,7 +169,12 @@ func (b *InMemBucket) GetRange(_ context.Context, name string, off, length int64
 		length = int64(len(file)) - off
 	}
 
-	return io.NopCloser(bytes.NewReader(file[off : off+length])), nil
+	return ObjectSizerReadCloser{
+		ReadCloser: io.NopCloser(bytes.NewReader(file[off : off+length])),
+		Size: func() (int64, error) {
+			return length, nil
+		},
+	}, nil
 }
 
 // Exists checks if the given directory exists in memory.

From dfed39a7c13e36f49ad115c92f386307c170dd09 Mon Sep 17 00:00:00 2001
From: Ashwanth Goli <iamashwanth@gmail.com>
Date: Thu, 10 Oct 2024 12:40:30 +0530
Subject: [PATCH 7/7] return err if Size is not set

Signed-off-by: Ashwanth Goli <iamashwanth@gmail.com>
---
 objstore.go | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/objstore.go b/objstore.go
index 116538ca..5bce3ef6 100644
--- a/objstore.go
+++ b/objstore.go
@@ -837,5 +837,9 @@ type ObjectSizerReadCloser struct {
 
 // ObjectSize implement ObjectSizer.
 func (o ObjectSizerReadCloser) ObjectSize() (int64, error) {
+	if o.Size == nil {
+		return 0, errors.New("unknown size")
+	}
+
 	return o.Size()
 }