From fc99a5d7869299ca4dbe4567ac521789e7f15402 Mon Sep 17 00:00:00 2001
From: John Starich <johnstarich@johnstarich.com>
Date: Thu, 25 Jun 2020 23:25:49 -0500
Subject: [PATCH 1/2] Add failing test for reading a small zip file

---
 zipfs/file_test.go       |  43 +++++++++++++++++++++++++++++++++++++++
 zipfs/testdata/small.zip | Bin 0 -> 149 bytes
 2 files changed, 43 insertions(+)
 create mode 100644 zipfs/file_test.go
 create mode 100644 zipfs/testdata/small.zip

diff --git a/zipfs/file_test.go b/zipfs/file_test.go
new file mode 100644
index 00000000..8a0aaee1
--- /dev/null
+++ b/zipfs/file_test.go
@@ -0,0 +1,43 @@
+package zipfs
+
+import (
+	"archive/zip"
+	"io"
+	"testing"
+)
+
+func TestFileRead(t *testing.T) {
+	zrc, err := zip.OpenReader("testdata/small.zip")
+	if err != nil {
+		t.Fatal(err)
+	}
+	zfs := New(&zrc.Reader)
+	f, err := zfs.Open("smallFile")
+	if err != nil {
+		t.Fatal(err)
+	}
+	info, err := f.Stat()
+	if err != nil {
+		t.Fatal(err)
+	}
+	chunkSize := info.Size() * 2 // read with extra large buffer
+
+	buf := make([]byte, chunkSize)
+	n, err := f.Read(buf)
+	if err != io.EOF {
+		t.Fatal("Failed to read file to completion:", err)
+	}
+	if n != int(info.Size()) {
+		t.Errorf("Expected read length to be %d, found: %d", info.Size(), n)
+	}
+
+	// read a second time to check f.offset and f.buf are correct
+	buf = make([]byte, chunkSize)
+	n, err = f.Read(buf)
+	if err != io.EOF {
+		t.Fatal("Failed to read a fully read file:", err)
+	}
+	if n != 0 {
+		t.Errorf("Expected read length to be 0, found: %d", n)
+	}
+}
diff --git a/zipfs/testdata/small.zip b/zipfs/testdata/small.zip
new file mode 100644
index 0000000000000000000000000000000000000000..65d45a1ce67c7b569f969545a25e354dc6f9af56
GIT binary patch
literal 149
zcmWIWW@Zs#-~d8&zzGy6&P~k8am&m}{p4}><jHW2^ZKVe8Ce(@{{Ii~X6Fc+cdc6x
msEQki1H2iTL>LezA<KbGLIrSh1H4(;KvIlAXbz-3!0G_8{};Fb

literal 0
HcmV?d00001


From e76d1f3bb566670441de86f267f82c60f0364b89 Mon Sep 17 00:00:00 2001
From: John Starich <johnstarich@johnstarich.com>
Date: Thu, 25 Jun 2020 23:27:17 -0500
Subject: [PATCH 2/2] Fix panic when not filling up zipfs's read buffer

---
 zipfs/file.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/zipfs/file.go b/zipfs/file.go
index 57d72012..355f5f45 100644
--- a/zipfs/file.go
+++ b/zipfs/file.go
@@ -61,7 +61,7 @@ func (f *File) Read(p []byte) (n int, err error) {
 	}
 	err = f.fillBuffer(f.offset + int64(len(p)))
 	n = copy(p, f.buf[f.offset:])
-	f.offset += int64(len(p))
+	f.offset += int64(n)
 	return
 }