feat: initial recursive archive cataloging impl

Signed-off-by: Keith Zantow <keith.zantow@anchore.com>

internal/archive/notify_test.go

@@ -0,0 +1,98 @@
+package archive
+
+import (
+	"archive/tar"
+	"bytes"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// recorder is what a consumer of these events looks like: one func, a type assertion for what it
+// cares about, and silence for everything else.
+type recorder struct {
+	overflows []EntriesOverflowed
+	other     int
+}
+
+func (r *recorder) notify(msg any) {
+	if e, ok := msg.(EntriesOverflowed); ok {
+		r.overflows = append(r.overflows, e)
+		return
+	}
+	r.other++
+}
+
+func TestNotify_reportsWhichArchiveSpilledAndWhy(t *testing.T) {
+	rec := &recorder{}
+	s := NewEntryStore(t.TempDir(), "lib/app.jar", rec.notify)
+	t.Cleanup(func() { require.NoError(t, s.Close()) })
+
+	charge := memCharge(8)
+	for _, body := range []string{"aaaa", "bbbbbb"} {
+		_, err := s.Add(regularHeader(body+".txt", int64(len(body))), bytes.NewReader([]byte(body)), charge)
+		require.NoError(t, err)
+	}
+
+	require.Len(t, rec.overflows, 1)
+	assert.Equal(t, "lib/app.jar", rec.overflows[0].Archive, "the event has to name the archive, or it says nothing actionable")
+	assert.Equal(t, MemoryLimitReached, rec.overflows[0].Reason)
+	assert.Equal(t, 2, rec.overflows[0].Entries, "a store moves everything it is holding, not just the entry that did not fit")
+	assert.Equal(t, int64(10), rec.overflows[0].Bytes)
+}
+
+func TestNotify_distinguishesPressureFromPolicy(t *testing.T) {
+	// a scan at its memory bound and a scan whose bound is zero are different findings: the first says
+	// the limit is biting, the second says nothing was ever going to be held
+	rec := &recorder{}
+	s := NewEntryStore(t.TempDir(), "app.jar", rec.notify)
+	t.Cleanup(func() { require.NoError(t, s.Close()) })
+
+	_, err := s.Add(regularHeader("a.txt", 3), bytes.NewReader([]byte("abc")), memCharge(0))
+	require.NoError(t, err)
+
+	require.Len(t, rec.overflows, 1)
+	assert.Equal(t, MemoryHoldsNothing, rec.overflows[0].Reason)
+}
+
+func TestNotify_nilHandlerIsTheNoOp(t *testing.T) {
+	s := NewEntryStore(t.TempDir(), "app.jar", nil)
+	t.Cleanup(func() { require.NoError(t, s.Close()) })
+
+	_, err := s.Add(regularHeader("a.txt", 3), bytes.NewReader([]byte("abc")), memCharge(0))
+	assert.NoError(t, err, "no handler must not mean no extraction")
+}
+
+func TestNotify_teeDeliversToEveryLiveHandler(t *testing.T) {
+	first, second := &recorder{}, &recorder{}
+	tee := Tee(nil, first.notify, nil, second.notify)
+	require.NotNil(t, tee)
+
+	tee(EntriesOverflowed{Archive: "app.jar", Entries: 1})
+
+	assert.Len(t, first.overflows, 1)
+	assert.Len(t, second.overflows, 1)
+}
+
+func TestNotify_teeOfNothingIsNil(t *testing.T) {
+	// a tee that would deliver to no one stays nil, so the guard at every call site keeps it free
+	assert.Nil(t, Tee())
+	assert.Nil(t, Tee(nil, nil))
+}
+
+func TestNotify_sendIsNilSafe(t *testing.T) {
+	var n Notify
+	n.Send(EntriesOverflowed{})
+}
+
+func TestNotify_directoryEntriesDoNotSpill(t *testing.T) {
+	// a directory carries no content, so it can never be the thing that pushes a store to disk
+	rec := &recorder{}
+	s := NewEntryStore(t.TempDir(), "app.jar", rec.notify)
+	t.Cleanup(func() { require.NoError(t, s.Close()) })
+
+	_, err := s.Add(tar.Header{Name: "lib/", Typeflag: tar.TypeDir, Mode: 0o755}, nil, memCharge(0))
+	require.NoError(t, err)
+	assert.Empty(t, rec.overflows)
+}