From efc7f6d94d08ad8e030cf2a705625054266fd889 Mon Sep 17 00:00:00 2001
From: Arran Walker <arran.walker@fiveturns.org>
Date: Sun, 12 Sep 2021 00:21:34 +0100
Subject: [PATCH] Fix buffer size limit

---
 archiver_options.go |  8 +++++++-
 archiver_test.go    | 47 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/archiver_options.go b/archiver_options.go
index 8bbbea4..8ef4533 100644
--- a/archiver_options.go
+++ b/archiver_options.go
@@ -4,7 +4,10 @@ import (
 	"errors"
 )
 
-var ErrMinConcurrency = errors.New("concurrency must be at least 1")
+var (
+	ErrMinConcurrency = errors.New("concurrency must be at least 1")
+	ErrMinBufferSize  = errors.New("buffer size option cannot be less than -1")
+)
 
 // ArchiverOption is an option used when creating an archiver.
 type ArchiverOption func(*archiverOptions) error
@@ -47,6 +50,9 @@ func WithArchiverConcurrency(n int) ArchiverOption {
 // written to temporary files before being written back to the zip file.
 func WithArchiverBufferSize(n int) ArchiverOption {
 	return func(o *archiverOptions) error {
+		if n < -1 {
+			return ErrMinBufferSize
+		}
 		o.bufferSize = n
 		return nil
 	}
diff --git a/archiver_test.go b/archiver_test.go
index e0d1fab..9fd2c21 100644
--- a/archiver_test.go
+++ b/archiver_test.go
@@ -301,6 +301,53 @@ func TestArchiveWithConcurrency(t *testing.T) {
 	}
 }
 
+func TestArchiveWithBufferSize(t *testing.T) {
+	testFiles := map[string]testFile{
+		"foo.go": {mode: 0666},
+		"bar.go": {mode: 0666},
+	}
+
+	tests := []struct {
+		buffersize int
+		pass       bool
+	}{
+		{-100, false},
+		{-2, false},
+		{-1, true},
+		{0, true},
+		{32 * 1024, true},
+		{64 * 1024, true},
+	}
+
+	files, dir := testCreateFiles(t, testFiles)
+	defer os.RemoveAll(dir)
+
+	for _, test := range tests {
+		func() {
+			f, err := ioutil.TempFile("", "fastzip-test")
+			require.NoError(t, err)
+			defer os.Remove(f.Name())
+			defer f.Close()
+
+			a, err := NewArchiver(f, dir, WithArchiverBufferSize(test.buffersize))
+			if !test.pass {
+				require.Error(t, err)
+				return
+			}
+
+			require.NoError(t, err)
+			require.NoError(t, a.Archive(context.Background(), files))
+			require.NoError(t, a.Close())
+
+			bytes, entries := a.Written()
+			require.EqualValues(t, 0, bytes)
+			require.EqualValues(t, 3, entries)
+
+			testExtract(t, f.Name(), testFiles)
+		}()
+	}
+}
+
 func TestArchiveChroot(t *testing.T) {
 	dir, err := ioutil.TempDir("", "fastzip-test")
 	require.NoError(t, err)