Restore --format table header support

Signed-off-by: Jhon Honce <jhonce@redhat.com>

2 files changed, 52 insertions, 0 deletions

diff --git a/cmd/podman/parse/template.go b/cmd/podman/parse/template.go
new file mode 100644
index 000000000..0b80f1b3a
--- /dev/null
+++ b/cmd/podman/parse/template.go
@@ -0,0 +1,22 @@
+package parse
+
+import (
+	"regexp"
+	"strings"
+)
+
+var rangeRegex = regexp.MustCompile(`{{\s*range\s*\.\s*}}.*{{\s*end\s*}}`)
+
+// TODO move to github.com/containers/common/pkg/report
+// EnforceRange ensures that the format string contains a range
+func EnforceRange(format string) string {
+	if !rangeRegex.MatchString(format) {
+		return "{{range .}}" + format + "{{end}}"
+	}
+	return format
+}
+
+// EnforceRange ensures that the format string contains a range
+func HasTable(format string) bool {
+	return strings.HasPrefix(format, "table ")
+}
diff --git a/cmd/podman/parse/template_test.go b/cmd/podman/parse/template_test.go
new file mode 100644
index 000000000..7880d9bec
--- /dev/null
+++ b/cmd/podman/parse/template_test.go
@@ -0,0 +1,30 @@
+package parse
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestEnforceRange(t *testing.T) {
+	tests := []struct {
+		input    string
+		expected string
+	}{
+		{"{{range .}}{{.ID}}{{end}}", "{{range .}}{{.ID}}{{end}}"},
+		{"{{.ID}}", "{{range .}}{{.ID}}{{end}}"},
+		{"{{ range . }}{{ .ID }}{{ end }}", "{{ range . }}{{ .ID }}{{ end }}"},
+		// EnforceRange does not verify syntax or semantics, that will happen later
+		{"{{range .}}{{.ID}}", "{{range .}}{{range .}}{{.ID}}{{end}}"},
+		{".ID", "{{range .}}.ID{{end}}"},
+	}
+
+	for _, tc := range tests {
+		tc := tc
+		label := "TestEnforceRange_" + tc.input
+		t.Run(label, func(t *testing.T) {
+			t.Parallel()
+			assert.Equal(t, tc.expected, EnforceRange(tc.input))
+		})
+	}
+}