feat(backend): zip page index with natural sort, zip-slip rejection, content hash

backend/internal/bookfile/zip_test.go

@@ -0,0 +1,85 @@
+package bookfile
+
+import (
+	"archive/zip"
+	"bytes"
+	"testing"
+)
+
+func zipOf(t *testing.T, names ...string) *bytes.Reader {
+	t.Helper()
+	buf := &bytes.Buffer{}
+	zw := zip.NewWriter(buf)
+	for i, n := range names {
+		w, err := zw.Create(n)
+		if err != nil {
+			t.Fatal(err)
+		}
+		w.Write([]byte{byte(i)})
+	}
+	zw.Close()
+	return bytes.NewReader(buf.Bytes())
+}
+
+func TestPageIndexSortAndFilter(t *testing.T) {
+	r := zipOf(t, "page10.jpg", "page2.jpg", "page1.jpg", "cover.PNG", "meta.xml", "sub/3.webp", "readme.txt")
+	idx, err := PageIndex(r, int64(r.Len()))
+	if err != nil {
+		t.Fatal(err)
+	}
+	want := []string{"cover.PNG", "page1.jpg", "page2.jpg", "page10.jpg", "sub/3.webp"}
+	if len(idx) != len(want) {
+		t.Fatalf("got %v", idx)
+	}
+	for i := range want {
+		if idx[i] != want[i] {
+			t.Fatalf("got %v want %v", idx, want)
+		}
+	}
+}
+
+func TestPageIndexRejectsSlip(t *testing.T) {
+	for _, bad := range []string{"../evil.jpg", "/etc/passwd.jpg", "a\\..\\b.jpg"} {
+		r := zipOf(t, bad)
+		if _, err := PageIndex(r, int64(r.Len())); err == nil {
+			t.Fatalf("entry %q must be rejected", bad)
+		}
+	}
+}
+
+func TestReadEntry(t *testing.T) {
+	buf := &bytes.Buffer{}
+	zw := zip.NewWriter(buf)
+	w, _ := zw.Create("p1.jpg")
+	w.Write([]byte("jpegbytes"))
+	zw.Close()
+	r := bytes.NewReader(buf.Bytes())
+	got, err := ReadEntry(r, int64(r.Len()), "p1.jpg")
+	if err != nil || string(got) != "jpegbytes" {
+		t.Fatalf("%q %v", got, err)
+	}
+	if _, err := ReadEntry(r, int64(r.Len()), "nope.jpg"); err == nil {
+		t.Fatal("missing entry must error")
+	}
+}
+
+func TestNaturalLess(t *testing.T) {
+	pairs := [][2]string{{"2", "10"}, {"a2b", "a10b"}, {"007", "7"}, {"a", "b"}, {"A", "a"}}
+	for _, p := range pairs {
+		if !NaturalLess(p[0], p[1]) {
+			t.Errorf("NaturalLess(%q,%q) want true", p[0], p[1])
+		}
+		if NaturalLess(p[1], p[0]) {
+			t.Errorf("NaturalLess(%q,%q) want false", p[1], p[0])
+		}
+	}
+}
+
+func TestHash(t *testing.T) {
+	if Hash(100, 200) == Hash(101, 200) || Hash(100, 200) != Hash(100, 200) {
+		t.Fatal("hash broken")
+	}
+	if len(Hash(1, 2)) != 16 {
+		t.Fatal("hash length")
+	}
+}