refactor: Consolidate handling of output to stdout

Signed-off-by: Evan Lezar <elezar@nvidia.com>

Author: elezar

cmd/nvidia-ctk/cdi/generate/generate.go

@@ -20,7 +20,6 @@ import (
 	"context"
 	"errors"
 	"fmt"
-	"os"
 	"path/filepath"
 	"slices"
 	"strings"
@@ -352,14 +351,6 @@ type generatedSpecs struct {
 func (g *generatedSpecs) Save(filename string) error {
 	filename = g.updateFilename(filename)
 
-	if filename == "" {
-		_, err := g.WriteTo(os.Stdout)
-		if err != nil {
-			return fmt.Errorf("failed to write CDI spec to STDOUT: %v", err)
-		}
-		return nil
-	}
-
 	return g.Interface.Save(filename)
 }
 

cmd/nvidia-ctk/cdi/transform/root/root.go

@@ -159,13 +159,5 @@ func (o transformOptions) getContents() ([]byte, error) {
 
 // Save saves the CDI specification to the output file
 func (o transformOptions) Save(s spec.Interface) error {
-	if o.output == "" {
-		_, err := s.WriteTo(os.Stdout)
-		if err != nil {
-			return fmt.Errorf("failed to write CDI spec to STDOUT: %v", err)
-		}
-		return nil
-	}
-
 	return s.Save(o.output)
 }

pkg/nvcdi/spec/spec.go

@@ -86,11 +86,16 @@ func (t *transfromAsValidator) Validate(s *specs.Spec) error {
 
 // Save writes the spec to the specified path and overwrites the file if it exists.
 func (s *spec) Save(path string) error {
-	pathWithExtension := s.ensureExtension(path)
+	if pathWithExtension := s.ensureExtension(path); pathWithExtension != "" {
+		return producer.Save(s.Raw(), pathWithExtension,
+			s.producerOptions()...,
+		)
+	}
+	if _, err := s.WriteTo(os.Stdout); err != nil {
+		return fmt.Errorf("failed to write CDI spec to STDOUT: %w", err)
+	}
 
-	return producer.Save(s.Raw(), pathWithExtension,
-		s.producerOptions()...,
-	)
+	return nil
 }
 
 // WriteTo writes the spec to the specified writer.